Next Article in Journal
Metabolic Effects and Safety Aspects of Acute D-allulose and Erythritol Administration in Healthy Subjects
Previous Article in Journal
The Effect of Nerolidol Renal Dysfunction following Ischemia–Reperfusion Injury in the Rat
Previous Article in Special Issue
In-Season Consumption of Locally Produced Tomatoes Decreases Cardiovascular Risk Indices
 
 
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Review

Valorization of Chicken Slaughterhouse Byproducts to Obtain Antihypertensive Peptides

by
Francisca Isabel Bravo
,
Enrique Calvo
,
Rafael A. López-Villalba
,
Cristina Torres-Fuentes
,
Begoña Muguerza
,
Almudena García-Ruiz
* and
Diego Morales
Nutrigenomics Research Group, Department of Biochemistry and Biotechnology, Universitat Rovira i Virgili, 43007 Tarragona, Spain
*
Author to whom correspondence should be addressed.
Nutrients 2023, 15(2), 457; https://doi.org/10.3390/nu15020457
Submission received: 22 December 2022 / Revised: 9 January 2023 / Accepted: 11 January 2023 / Published: 15 January 2023

Abstract

:
Hypertension (HTN) is the leading cause of premature deaths worldwide and the main preventable risk factor for cardiovascular diseases. Therefore, there is a current need for new therapeutics to manage this condition. In this regard, protein hydrolysates containing antihypertensive bioactive peptides are of increasing interest. Thus, agri-food industry byproducts have emerged as a valuable source to obtain these hydrolysates as they are rich in proteins and inexpensive. Among these, byproducts from animal origin stand out as they are abundantly generated worldwide. Hence, this review is focused on evaluating the potential role of chicken slaughterhouse byproducts as a source of peptides for managing HTN. Several of these byproducts such as blood, bones, skins, and especially, chicken feet have been used to obtain protein hydrolysates with angiotensin-converting enzyme (ACE)-inhibitory activity and blood pressure-lowering effects. An increase in levels of endogenous antioxidant compounds, a reduction in ACE activity, and an improvement of HTN-associated endothelial dysfunction were the mechanisms underlying their effects. However, most of these studies were carried out in animal models, and further clinical studies are needed in order to confirm these antihypertensive properties. This would increase the value of these byproducts, contributing to the circular economy model of slaughterhouses.

1. Introduction

Hypertension (HTN) or high blood pressure (BP) is a severe medical condition suffered by over 1.28 billion people aged 30–79 years [1]. This chronic disease is also one of the main risk factors for cardiovascular diseases (CVD), as well as brain, heart, or kidney diseases, among others. Consequently, a reduction in its growing incidence is of great importance, targeting its reduction by 33% by 2030 [1]. Hence, there is a need for new strategies to manage HTN [2]. In this context, bioactive peptides, which are small specific protein fragments (2–20 amino-acid residues), released from the native protein via chemical or enzymatic hydrolysis, bacterial fermentation, or food processing, are of increasing interest. Thus, these functional peptides present interesting biological activities such as antioxidant, anti-inflammatory, antidiabetic, and antimicrobial [3]. Regarding HTN, there is strong evidence that they can help to prevent or ameliorate the onset or progression of this disease; at the same time, they might overcome some of the side or adverse effects of existing therapeutic treatments [4,5,6].
Among the diversity of potential dietary sources used to obtain bioactive peptides, agri-food industry byproducts have emerged as an excellent option [5,7]. In particular, those from animal origin are of special interest as they are both rich in proteins [8,9,10,11], which usually can be easily extracted, and inexpensive. In this regard, poultry slaughterhouse byproducts such as blood, feathers, soft meat, skins, or bones, mainly those generated from broilers, stand out due to their elevated generation [12]. This growing industry represented 40% of global meat production in 2020 [13]. Consequently, the management of these wastes must be improved to tackle this growing problem. Thus, the use of these products to obtain bioactive peptides would be an excellent opportunity to valorize these byproducts within the principles of the circular economy [14].
Chicken byproducts are mainly composed of collagen (abundant in bones, legs, feet, etc.) or other structural proteins such as keratin in the case of feathers [15,16]. It has been reported that collagen, from different origins, is an excellent source of peptides with a wide range of bioactivities including anti-skin aging, lipid-lowering, metal-chelating, antioxidant, antidiabetic, or immune modulation [17,18,19]. Moreover, collagen hydrolysates have demonstrated to exert both angiotensin-converting enzyme-inhibitory (ACEi) and antihypertensive activities [18,20,21]. ACE inhibition is a usual and effective methodology to search for antihypertensive peptides [5,22,23] as this enzyme plays an important role in BP regulation [24]. In fact, ACE inhibitors are first-line treatments for HTN as they effectively decrease BP [25].
Considering all these facts, the present review is focused on evaluating the potential role of broiler slaughterhouse byproducts as a source of peptides in the management of HTN.

2. Materials and Methods

Studies focused on chicken byproducts, peptides and the evaluation of their anti-hypertensive effects were searched using the database Web of Knowledge (https://www.webofscience.com/ (accessed on 8 July 2022). Combinations of several search terms such as “ACE inhibitory activity”, “antihypertensive activity/effect”, “blood”, “blood pressure”, “bone/s”, “byproduct/s“, “chicken”, “feather/s”, “foot/feet”, “leg/s”, “hydrolysate/s”, “liver”, “peptides”, “renin activity”, “residues”, “skin”, “trachea”, “viscera”, “waste/s” were applied. After the search, studies were reviewed, selected and classified according to the studied chicken byproduct, in vitro study and/or antihypertensive effect.

3. Results

3.1. Poultry Meat Industry and Chicken Byproducts

Despite the growing vegan, vegetarian, and environmental movements that encourage the consumption of a plant-based diet, the consumption of poultry meat has increased in the last decades. It is estimated that poultry farming will be the livestock sector with the highest projection until 2050 [12,26,27]. According to Food and Agriculture Organization of the United Nations, this industry represented 40% of global meat production in 2020, with chicken the majority poultry species contributing to meat production (90%) [13]. In 2021, the chicken meat production worldwide was estimated at about 80.2 million metric tons of broiler meat [28]. Moreover, about 70–75% of the live bird weight is estimated to be the yield of poultry carcass [29]. As a result, the generation of chicken slaughterhouse wastes is high and growing, making their correct management crucial. Hence, these untapped residues must be subjected to reuse strategies in line with circular economy principles, with the aim of reducing their accumulation and pollution. Moreover, this will lead to the development of new added-value products such as fertilizers [30,31], biogas [32,33], textile materials (keratin from feathers) [34], and functional foods based on chicken proteins, hydrolysates, and peptides that exert biological activities such as the ability to reduce HTN risk [35,36].
Several chicken slaughterhouse byproducts, such as legs or feet, blood, bone residues from mechanically deboned chicken meat and cartilages, skin, feathers, trachea, viscera, and combs/wattles, may have potential as a source of antihypertensive peptides given their protein content (Table 1). In this sense, feather is a major slaughterhouse byproduct, corresponding to 5–7% of an adult chicken weight [37]. It stands out for its high protein content, reaching values up to 85% [38], with keratin being the major protein component (over 90% of total protein) [39]. Antioxidant and hypocholesterolemic effects have been observed for keratin-based peptides [40,41]. Slaughterhouses also generate blood, which corresponds to 6–7.5% of live chicken weight [42]. It is mainly intended for animal feed as it comprises 80–90% protein (dry weight) (Table 1), mainly hemoglobin (over 70% of total protein) [43]. However, antioxidant peptides have been obtained from blood [44,45]. Chicken bones come from legs, necks, backs, carcasses, etc., mainly obtained when meat is deboned. Their uses are restricted to soups, broths, and animal feed but their collagen content has placed these components as interesting materials for enzymatic hydrolysis [46,47]. Related to bones, cartilages are a source of bioactive molecules such as hyaluronic acid or chondroitin sulfate that are related to anti-atherosclerotic, anti-osteoarthritis, and antiaging effects [48]. Moreover, tracheas (or windpipes), despite their lower impact as a chicken byproduct, are very rich in proteins (69% of protein (dry weight)). Moreover, the hydrolysis of their proteins led to the release of antioxidant and antihypertensive agents [49]. Another relevant slaughterhouse byproduct is chicken skin, which corresponds to over 8–20% of chicken carcass weight together visible fat [50]. It is considered underutilized since it is a source of fatty acids, as well as collagen, elastin, or gelatin that have been hydrolyzed to obtain antioxidant and antihypertensive peptides [51,52]. Poultry slaughterhouses also generate the viscera, which includes hearts, livers, and gizzards, with high-value protein content. It is consumed by some people in different countries, but it is usually discarded or directed to aquaculture feed. Specific fractions of viscera protein hydrolysates have demonstrated free-radical-scavenging and ACEi activities [53,54,55]. Chicken feet are used in some culinary preparations, mainly in Asiatic countries; however, many countries do not consume this chicken product, and great amounts of them are usually discarded. Because of their high protein (particularly collagen) content (18–23 of protein/100 g of wet feet), they are used as a source of gelatin [56]. In addition, foot hydrolysates have been utilized as fat replacers [16,57]. Lastly, many combs and wattles, which are discarded particularly from female animals, are a source of hyaluronic acid, a potent antioxidant [58].

3.2. ACEi and Antihypertensive Effects of Hydrolysates from Chicken Slaughterhouse Byproducts

Chicken slaughterhouse byproducts have been used as a source of peptides able to reduce high BP. In general, these peptides were selected in vitro according to their capacity to inhibit enzymes involved in the renin–angiotensin–aldosterone system (RAAS), mainly the ACE. RAAS is an essential system involved in the regulation of cardiovascular function and fluid homeostasis, including BP regulation (see Ibarz-Blanch et al., 2022 [76]). Briefly, the system is activated when BP drops, producing the release of renin by juxtaglomerular cells. This protease cleavages the circulating angiotensinogen, releasing the peptide angiotensin (Ang) I. Then, this peptide is hydrolyzed by ACE, generating the peptide Ang II. Ang II is a key component involved in the BP increase as it produces vasoconstriction of vascular smooth muscle cells and stimulates the release of the endothelium-derived vasoconstrictor factor endothelin-1 (ET-1) and endothelial reactive oxygen species (ROS) [77,78]. Excessive ROS leads to a decrease in the production and the bioavailability of nitric oxide (NO), the main endothelial-derived vasodilator factor, which is produced by endothelial NO synthase (eNOS) action [76]. In this regard, excessive superoxide anions can scavenge NO, as well as produce “eNOS uncoupling” [79,80]. The eNOS uncoupling refers to the condition in which eNOS produces ROS (superoxide anions) instead of NO [80] (see [76] for more details about endothelial-derived factors and their relationship). Moreover, Ang II stimulates the secretion of both aldosterone by the adrenal cortex, which increases water and sodium reabsorption and potassium excretion in nephrons, and the antidiuretic hormone by the hypothalamus, which promotes the intake of water and water reabsorption in the collecting ducts of nephrons [81,82]. Thus, ACE inhibition is crucial in BP reduction not only by decreasing the Ang II production but also because it cleaves the vasodilator bradykinin, losing its vasoactive action [83].
As aforementioned, chicken byproducts are composed of a high protein content, and they have been used as a raw material for the obtainment of ACEi and antihypertensive hydrolysates and peptides.

3.2.1. Blood

Several studies have been focused on the valorization of chicken blood or its components, including corpuscle and plasma fractions or isolated red blood cells, through the generation of ACEi peptides [66,84,85,86,87] (Table 2). Results from these studies indicated that ACEi activity of the blood protein hydrolysates was deeply influenced by hydrolysis conditions and protein substrate [66,84]. As expected, the hydrolytic enzyme used was one of the factors that conditioned the bioactivity of blood protein hydrolysates obtained. In that way, under the same hydrolysis conditions, Alcalase® was the enzyme that generated the best ACEi hydrolysates from whole blood compared with Prozyme 6, Protease N, or Thermolysin®. Furthermore, a positive correlation was observed between ACEi activity and the degree of hydrolysis; a higher hydrolysis time or enzyme concentration corresponded to a higher ACEi activity [66]. Wongngam et al. (2020) also observed differences in the ACEi activity of blood-derived peptides depending on the enzyme (Alcalase®, Papain®, Pepsin, Thermolysin, and SK1-3-7), as well as on the protein substrate (whole blood, blood plasma, and blood corpuscle) employed [84]. Specifically, the most bioactive hydrolysates were those obtained by hydrolysis of blood cells with Alcalase® and Thermolysin®, being those that also showed a higher hydrolysis degree. The optimized hydrolysis conditions with Alcalase® for blood corpuscle were set to 51.1 °C for 6 h with 4% enzyme. On the other hand, the ACEi activity of this hydrolysate generated in optimum conditions increased 2.5-fold when peptides <1 kDa were obtained. Interestingly, both optimized blood corpuscle hydrolysate and its peptic fraction (<1 kDa) showed a potent antihypertensive effect in spontaneously hypertensive rats (SHR) after an acute administration. Best systolic BP (SBP) reductions were found at doses of 600 mg/kg body weight (BW) for the hydrolysate and 100–200 mg/kg BW for the fraction at 6 (57.7 mmHg) and 12 h (70.9 mmHg), respectively. The <1 kDa fraction seemed to be the best as it produced a higher and more prolonged antihypertensive effect with a lower dose than the whole hydrolysate. However, both of them showed similar BP-lowering effects in SHR administered for 4 weeks [84].
Another way to increase the ACEi activity of blood protein hydrolysates is performing the plastein reaction [86]. This effect has also been reported in the generation of soybean and casein hydrolysates [88,89]. The plastein reaction is a technique based on treating high-concentrated protein hydrolysates with proteases to form a precipitate, thixotropic colloid, or thixotropic viscous gel-like substance [90]. Peptides are released into the remaining supernatant, and it is typical to add free amino acids during the reaction [86]. In this regard, it can be noted that the ACEi activity of a hydrolysate obtained from blood plasma and trypsin (6000 U/g) at 37 °C, 5 h, and pH 8 increased through a trypsin- and papain-catalyzed plastein reaction (conditions: 15 min and 30% of hydrolysate) [86]. Moreover, a positive correlation was observed between ACEi activity and different parameters of trypsin-catalyzed plastein reaction in plasma protein including enzyme/substrate ratio (up to 6000 U/g), temperature (up to 40 °C), time (up to 5 h), and pH (up to 8). The type of exogenous amino acids added to the hydrolysate during the plastein reaction also changed the ACEi activity of the hydrolysates (leucine > tyrosine > histidine > cysteine > valine) [86].
Lastly, the effect of the type of hydrolysis (chemical or enzymatic) used for the generation of ACEi peptides from chicken blood proteins was also evaluated [87]. Hydrolysates obtained from isolated red blood cells using both types of hydrolysis, chemicals under acid conditions and enzymatic (Alcalase®), showed the same range of activity (18.7–49.4% and 14.2–47.7%, respectively). In this study, the response surface methodology was employed to optimize the hydrolysis conditions for obtaining ACEi peptides. In particular, 50 °C, 32 h, and 0.03 N HCl were established for the acid hydrolysis, whereas 60 °C, 2 h, and 2.5% Alcalase® were determined for the enzymatic hydrolysis [87]. Furthermore, it was also shown that HCl concentration and temperature, and enzyme concentration for acid and enzymatic hydrolysis, respectively, were keys for the generation of hydrolysates with higher ACEi activity [87].

3.2.2. Bones

Chicken bones are traditionally used as an economic source of calcium for mineral supplements; however, hydrolysates from chicken bone proteins have also shown ACEi activity (Table 2), even higher than carnosine, a dipeptide with known antihypertensive properties [91]. In this regard, it has been reported that, after 4 and 8 h of bone leg protein hydrolysis with Alcalase®, the obtained hydrolysates showed around 85% of ACEi activity, higher than after trypsin or pepsin hydrolysis [60]. Interestingly, the good activity in vitro of the hydrolysate was also correlated with in vivo observations, in which the 4 h hydrolysate at 50 mg/kg BW decreased the SBP of SHR after its acute administration from 2 to 8 h post administration in a similar manner to captopril at 1.5 mg/kg BW [92]. In this study, the hypotensive effect of this hydrolysate was also discarded in normotensive rats. In addition to ACEi activity, the chicken bone hydrolysate also attenuated the development of age-induced HTN and heart and vascular hypertrophy, when it was administered daily during 8 weeks [92,93]. This is of relevance as HTN was associated with the presence of cardiac hypertrophy (one of the main causes of cardiovascular mortality and morbidity), stretching of smooth muscle cells, and thickening of the vascular wall (present in several cardiovascular diseases) [94,95,96].
Table 2. Angiotensin-converting enzyme inhibitory and antihypertensive activities shown by the hydrolysates obtained from chicken byproducts.
Table 2. Angiotensin-converting enzyme inhibitory and antihypertensive activities shown by the hydrolysates obtained from chicken byproducts.
By-ProductHydrolisis ConditionsIn Vitro ACEi ActivityIn VivoReferences
GeneralComponent% *Ic50 (µg/mL)Animal ModelOral DosesPeriodEffect on BPMechanism
BloodCorpuscleAlcalase® 4%, 6 h, 51.1 °C, pH 8.037.7 (0.2 mg/mL)341SHR600 mg/kg BWSingle↓ SBP (57.7 mmHg, 6 h pa) [84]
SHR600 mg/kg BWDaily for 4 weeks↓ SBP (~60 mmHg)
↓ DBP (~30 mmHg)
Fraction < 1 KDa of hydrolysate (Alcalase® 4%, 6 h, 51.1 °C, pH 8.0) 138SHR100 mg/kg BWSingle↓ SBP (70.9 mmHg, 6 h pa)
↓ DBP (47 mmHg, 6 h pa)
-
SHR100 mg/kg BWDaily for 4 weeks↓ SBP (~60 mmHg)
↓ DBP (~30 mmHg)
-
MealAlcalase® 10%, 5 h, 50 °C, pH 8.0 340 [66]
Isolated red blood cells0.03 N HCl, 32 h, 50 °C44 (ne) [87]
Alcalase® 2.5%, 2 h, 60 °C45 (ne)
PlasmaTrypsin, 6000 U/g (E/S ratio), 5 h, 37 °C, pH 7.554 (1 mg/mL) [86]
Bones Pepsin 1:100 (w/w), 6 h, 36 °C, pH 2.0 220 [97]
LegAlcalase® 1:50 (E/S ratio) 8 h, 50 °C, pH 8.086 (ne)612 and 945 [60,92]
Alcalase® 1:50 (E/S ratio), 4 h, 50 °C, pH 8.084 (ne)545 and 1960SHR50 mg/kg BWSingle↓ SBP
(26 mmHg, 4 h pa)
Alcalase® 2% (E/S ratio), 4 h, 50 °C, pH 8.0 545 50 mg/kg BWDaily, 8 weeksAvoid increase of SBP (33 mmHg)↑ Heart weight
↓ Heart/BW ratio
↓ Wall thickness in intramyocardial coronary vessels
[92,93]
Combs and Wattles Alcalase® 5% (E/S ratio), 4 h, 50 °C, pH 8.0 134 [98]
Feet Protamex® 0.4 AU/g prot, 2 h, 50 °C, pH 7.0 27SHR55 mg/kg BWSingle↓ SBP (26.3 mmHg, 6 h pa)↓ Plasma ACE activity[99]
Protamex® 0.4 AU/g prot, 2 h, 50 °C, pH 7.0 9Diet-induced hypertensive rats55 mg/kg BWDaily for 3 weeks↓ SBP (~20 mmHg)↑ GSH levels,
Et-1,
Nox4
Sirt1
[100]
Protamex® 0.4 AU/g prot, 2 h, 50 °C, pH 7.0 27SHR85 mg/kg BWSingle↓ SBP
(30.5 mmHg, 6 h pa)
[99]
Fraction <6000 Da: Aspergillus oryzae protease 0.1% 260 [101]
Fraction <3000 Da: Aspergillus oryzae protease (0.1%) + Protease FP, 24 h, 50 °C, pH 7.0 130SHR3 g/kg wtSingle↓ SBP (~50 mmHg, 6 h pa) [101]
Fraction <3000 Da: Aspergillus oryzae protease (0.1%) + Protease FP, 24 h, 50 °C, pH 7.0 130SHR3 g/kg wtDaily for 4 weeks↓ SBP (~33 mmHg)
Fraction <3000 Da: Aspergillus oryzae protease (0.1%) + Protease FP, 24 h, 50 °C, pH 7.0 Hypertensive rats (Wistar Kyoto rats + L-NAME) 2.0 g/kgSingle ↑ Serum NO levels (1 h pa)[102]
Fraction <3000 Da: Aspergillus oryzae protease (0.1%) + Protease FP, 24 h, 50 °C, pH 7.0 Hypertensive rats (Wistar Kyoto rats + L-NAME)2.0 g/kgDaily for 8 weeks↓ SBP (~20 mmHg, 4 week pa)↓ Hypertrophy of the arterial intima and the myofibrils in thoracic aorta
↑ Vasorelaxation of thoracic aorta
↓Plasma iCAM-1 levels
Fraction <3000 Da: Aspergillus oryzae protease (0.1%) + Protease FP, 24 h, 50 °C, pH 7.0 Mildly hypertensive subjects5.2 gDaily for 4 weeks↓ SBP (11.8 mmHg, 2 weeks pa)
↓ DBP (4.1 mmHg, 2 weeks pa)
↓ Plasma renin activity (30%)
↑ EPC colonies
[103]
Fraction <3000 Da: Aspergillus oryzae protease (0.1 %) + Protease FP, 24 h, 50 °C, pH 7.0 Mildly and pre-hypertensive subjects2.9 gDaily for 12 weeks↓ SBP (5.3 mmHg)↓ Brachial–ankle pulse wave velocity (righ arm and average of both arms)[104]
Feathers Chryseobacterium sp. kr6, 24 and 48 h, 30 °C, pH 8.053 and 65 (for 24 and 48 h, respectively) (ne) [105]
SkinsThighAlcalase® 3% (w/w, protein basis), 4 h, 55 °C, pH 8.0.80 (ne)550SHR100 mg/kg BW ↓ SBP (~28–34 mmHg, 4–6 h pa) [52,106]
BreastPepsin 1% (w/w, protein basis), 2 h, 37 °C, pH 2.0 + Pancreatin
1% (w/w, protein basis), 4 h, 37 °C, pH 7.5
~78 (ne)640SHR ↓ SBP (31 mmHg, 6 h pa)
Thigh and breastMixture of two hydrolysates (1:1)
Thigh + Alcalase® 3% (w/w, protein basis), 4 h, 55 °C, pH 8.0;
Breast + pepsin 1% (w/w, protein basis), 2 h, 37 °C, pH 2.0 + Pancreatin
1% (w/w, protein basis), 4 h, 37 °C, pH 7.5
0.5%Daily for 6 weeks↓ SBP (31 mmHg)↓ Plasma ACE activity[107]
Thigh and breastMixture of two hydrolysates (1:1)
Thigh + Alcalase® 3% (w/w, protein basis), 4 h, 55 °C, pH 8.0;
Breast + pepsin 1% (w/w, protein basis), 2 h, 37 °C, pH 2.0 + Pancreatin
1% (w/w, protein basis), 4 h, 37 °C, pH 7.5
SHR1%Daily for 6 weeks↓ SBP (36 mmHg)↓ Plasma ACE activity
↑ Urine creatinine
↑ Urine L-isoleucine
↓ Urine uric acid
↓ Urine N2-acetyl-ornithine
↑ Urine N1-acetylspermidine
↓ Urine symmetric dimethylarginine
↑ Urine pentahomomethionine
↓ Urine buthionine sulfoximine
↓ Plasma tranexamic acid
↑ Plasma 13-docosenamide
↓ Plasma Vitamin E succinate
↑ Plasma PS(O-16:0/15:0)
↑ Plasma PS(O-18:0/15:0)
Trachea Alcalase® 1% (w/w protein), 1 h, 50 °C, pH 8.0 422 [49]
ResiduesMixtureAlcalase® 1%, (w/w residue), 2.5 h, 60 °C 273SHR3%Daily for 16 weeks↓ SBP (26 mmHg)↓ Aorta ACE activity[108]
VisceraIntestine, spleen, gall bladder, and connective tissuesAutolytic degradation of tissue protein (6 h, 55 °C, pH 2.8) 350–2650 [54,55]
LiverPediococcus acidilacticiN-CIM5368 24 h, 37 °C pH 4.0 or Alcalase® 2.5 L, 1.5% (v/w), 1.5 h, 45 °C Cyclophosphamide-induced anemic mice (Swiss-albino female mice)Diet deficient in iron + 1.5%, 3%, and 4.5%Daily for 4 weeksRestore BW
Restore hemoglobin levels
↑ Plasma antioxidant activity
[109]
Alcalase® 2.4 L and Flavourzyme® 500 L (1:1), 2 h, 50 °C81 (ne) [53]
Abbreviations: ACEi activity: angiotensin-converting enzyme-inhibitory activity; BP: blood pressure; BW: body weight; DBP: diastolic blood pressure; EPC: endothelial progenitor cells; Et-1; endothelin 1 gene; E/S: enzyme/substrate; GSH: reduced glutathione; L-NAME: N(ω)-nitro-L-arginine methyl ester; ne: not specified; NO: nitric oxide; Nox4: NADPH oxidase subunit 4 gene; pa: post administration; PS; phospholipids; SBP: systolic blood pressure; SHR: spontaneously hypertensive rats; Sirt1: sirtuin 1 gene; * Numbers in brackets indicate the concentration of protein for testing the ACEi activity. ↑ and ↓ indicate increase or decrease of a parameter, respectively.

3.2.3. Chicken Feet/Legs/Claws

Chicken feet, also known as legs or claws (yellow part of the legs), have been used to obtain ACEi hydrolysates (Table 2). In particular, the first study using this byproduct for this purpose was conducted in 2008 [101] and showed good ACEi activity in the fraction <6000 Da of a chicken-leg protein hydrolysate obtained with Aspergillus oryzae proteases (0.1%). Moreover, its bioactivity was increased when it was further processed with other enzymes (protease FP, protease N, or protease A amano G) or when it was subjected to a gastrointestinal digestion process using 1% pepsin and trypsin/chymotrypsin at 37 °C and pH 7.0 for 1 h [101]. In addition to ACEi, the fraction <3000 Da of the hydrolysate obtained with Aspergillus oryzae proteases and further hydrolyzed with the FP protease also showed antihypertensive effects in SHR after an acute and a long-term administration [101]. Moreover, the mechanisms involved in this antihypertensive effect were also investigated in N(ω)-nitro-L-arginine methyl ester (L-NAME)-induced hypertensive rats [102]. Concretely, animals administered with the hydrolysate showed higher serum NO levels, better aorta vasodilatation, a lower grade of aorta hypertrophy, and lower plasma intercellular adhesion molecule-1 (iCAM-1) levels than the hypertensive control group. These results reflected an improvement in the cardiovascular system, including in the endothelial functionality. In this regard, the endothelium also plays a key role in BP regulation by producing molecules with vasoactive actions, holding blood fluidity, and regulating vascular tone, vascular smooth muscle cell functionality, and immune and inflammation response [110,111]. Endothelial dysfunction has been associated with different diseases including HTN, atherosclerosis, and diabetes [112]. It is characterized by an imbalance in the proportion of endothelial-derived vasodilator (NO, prostaglandin) and vasoconstrictor (ET-1) factors, a reduction in the bioavailability of the endothelial vasodilator NO, and an increase in the vascular smooth muscle contractibility [113,114]. In that way, it is important to mention that serum levels of iCAM-1 have been associated with endothelial dysfunction and other CVD such as myocardial infarction, coronary heart disease, carotid, and some types of atherosclerosis [115,116,117,118]. iCAM-1, whose expression is upregulated by cytokines in endothelial cells, is involved in the formation and development of atherosclerotic lesions as it stimulates the adhesion of leukocytes to the endothelium and their transmigration into the subendothelial space [119]. On the other hand, the BP-lowering effects of this leg-derived hydrolysate were also validated in prehypertensive and mildly hypertensive subjects. In this regard, a significant reduction in SBP was observed in these volunteers after consuming 5.2 g/day of the hydrolysate for 2 weeks. Its effects were associated with its action on the RAAS and vascular endothelium as a strong reduction in the plasma renin activity and a significant increase in the blood endothelial progenitor cells were observed in these treated volunteers [103]. Endothelial progenitor cells are involved in vascular repair [120]. Moreover, a significant reduction in SBP was also reported after consumption of 2.9 g/day for mildly and prehypertensive subjects with respect to control volunteers [104]. The ingestion of the hydrolysate also led to a reduction in the brachial–ankle pulse wave velocity. This parameter indicates arterial stiffness and is a potential predictor of HTN and stroke development [121].
More recently, our group obtained a chicken foot hydrolysate denominated Hpp11, characterized by an excellent ACEi activity (IC50 = 27 µg/mL). The enzymatic solution Protamex® was employed for the generation of this hydrolysate [99]. A considerable reduction in SBP was shown after acute administration at 55 and 85 mg/kg BW. Specifically, the maximum effect was observed at 6 h post administration (−26.33 and −30.45 mmHg for 55 and 85 mg/kg BW, respectively). The BP-lowering effects were similar to those found with a high dose of the antihypertensive drug captopril (50 mg/kg BW) [99]. An undesirable hypotensive effect was also discarded in normotensive rats. Moreover, it is important to highlight that Hpp11 (55 mg/kg BW) showed functionality after a long-term administration (3 weeks), observing BP-lowering effects from the first week of consumption until the end of the study [100]. Its impact on BP in diet-induced hypertensive rats was associated with an improvement in both the oxidative stress, increasing hepatic reduced glutathione (GSH) levels, and in the endothelial dysfunction, downregulating Et-1 expression and upregulating Sirt-1 expression in aorta [100]. The effects of sirtuin 1 (SIRT-1) on the endothelium are linked to a vasodilator function, acting on endothelial NO production and bioavailability. Specifically, it activates eNOS by deacetylation, stimulates the transcription of eNos, and inhibits the activity of NADPH oxidase (NOX), reducing the production of ROS by NOX [76,122,123]. Lastly, Hpp11 was combined with other bioactive compounds including a grape seed proanthocyanidin extract, a berry anthocyanidin extract, and conjugated linoleic acid in order to elaborate a multifunctional product to manage metabolic syndrome [124,125,126]. This product also exerted a potent reduction in SBP in diet-induced hypertensive rats after its daily intake for 3 weeks [125].

3.2.4. Skins

The ACEi activity of skin hydrolysates is influenced by the enzyme type and concentration used in the hydrolysis process, as well as by the skin type. Thus, hydrolysis using Alcalase® produced hydrolysates with better activity than the combination of pepsin/trypsin in skin from both breast and thigh [52]. Hydrolysates from both skin breast proteins with 1% pepsin/pancreatin and skin thigh proteins with 3% Alcalase® also showed a potent antihypertensive effect that lasted until 24 h post administration [106]. When the combination of both hydrolysates was administered at 0.5% and 1% BW to SHR for 6 weeks, relevant antihypertensive effects were observed from the first week of administration, reaching a plateau at the third week of treatment. A metabolomics study indicated that this mixture of skin hydrolysates acted on the RAAS system and vascular function [107]. Additionally, a reduction in plasma ACE activity was observed, together with an increase in urine creatinine levels, which was associated with the arginine metabolism and NO production (Table 2). In contrast, a decrease in urine uric acid and plasma α-tocopherol succinate (vitamin E succinate) was also observed, which would be indicative of a reduction in oxidative stress [107]. Elevated serum uric acid levels have been related to the development of HTN as it produces oxidative stress, which would reduce the endothelial NO availability, and acts on RAAS system, increasing both intrakidney Ang activity and plasma renin activity [127]. It is known that α-tocoferol, a potent antioxidant, can modulate the activation and or transcription of several genes involved in oxidative stress including NOX, superoxide dismutase, NOS, or ciclooxigenase-2, leading to its reduction [128]. Thus, a reduction in urine α-tocoferol succinate would be indicative of increased free-radical scavenging [107]. Sarbon and colleagues also demonstrated the antihypertensive effects of peptides isolated from gelatin from chicken skin hydrolyzed with Collagenase, Alcalase®, and Pronase E. After ultrafiltration, the isolation of small-molecular-weight peptides increased the ACEi activity of the hydrolysates, which was comparable to that obtained with captopril [129]. In the in vivo study, a single administration of the peptides was more effective than losartan in reducing the SBP of SHR for 24 h.

3.2.5. Other Chicken Byproducts

Although much less studied, feather, trachea, viscera, combs, wattles, and chicken residues (unspecified residues) have also been used to obtain peptides with in vitro ACEi activity (Table 2) [49,53,98,105,108]. However, the antihypertensive effects of these hydrolysates remain unexplored. In this regard, two independent studies showed that Alcalase® was the best enzyme in producing ACEi peptides using trachea and chicken residues in comparison to the enzyme solutions Flavourzyme®, Protamex®, Papain®, Bromelain®, or Esperase® [49,108]. However, the best results in viscera were found when it was treated with Neutrase® 0.8 L, a binary mixture of Flavourzyme® 500 L and Alcalase® 2.4 L (1:1), and a ternary mixture of Flavourzyme® 500 L, Alcalase® 2.4 L, and Neutrase® 0.8 L [53]. Regarding feathers, they were fermented with Chryseobacterium sp. kr6 [105], a bacterium isolated directly from feathers, which produces four different extracellular alkaline keratinases [91]. This process helps to solubilize feather proteins, producing in turn bioactive peptides [105].

3.3. ACEi and Antihypertensive Effects of Chicken Byproduct-Derived Peptides

In addition to the ACEi activity and antihypertensive effects of the hydrolysates, some studies have identified the peptides involved in the bioactivity of the hydrolysates (Table 3). Generally, the amino-acid composition of the peptides, especially at both ends of the sequence, determines their ACEi activity. In this regard, it has been observed that the presence of hydrophobic residues such as Trp, Tyr, Pro, or Phe at the C-terminal end, as well as aliphatic amino acids such as Gly, Val, Leu, and Ile at the N-terminal position, leads to higher ACE inhibitions [130,131,132]. Specifically, ACEi peptides have been identified in hydrolysates from feet, blood corpuscle, legs with claws, bone, viscera, or a mixture of combs and wattles, showing IC50 values lower than 100 µM in many cases [22,85,97,98,133]. The protein source of these peptides depends on the used byproduct. For example, in combs and wattles, the main sources of ACEi peptides were collagen and elastin [98], while, in blood corpuscle, the main sources were cytochrome Bc1, hemoglobin, and fibrinogen, among others [85]. In addition, antihypertensive effects of peptides isolated from feet, bone, and blood corpuscle hydrolysates have also been evidenced in SHR [22,97,101,134]. Concretely, these were the amino-acid sequences QVGPLIGRYCG, AVFQHNCQE, VSKRLNGDA, GAOGLOGP, and YYRA (Table 3), which had a length between four and 11 amino-acid residues. In addition, these peptides showed an excellent ACEi activity, which could be associated to the presence of Val and/or hydrophobic amino acids/Glu at their N- and C-terminal ends, respectively [22,23]. In this regard, the peptides QVGPLIGRYCG and AVFQHNCQE, isolated from a Protamex®-digested foot hydrolysate, showed antihypertensive effects in SHR (10 mg/kg BW), exerting the maximum BP reduction at 6 h post administration (−10.94 and −25.07 mmHg, respectively) [22]. Additional studies showed that AVFQHNCQE, which is hydrolyzed during gastrointestinal digestion and seems not to be absorbed by gastrointestinal tract, displays an antihypertensive action through an increase in NO levels, which is mediated by the activation of opioid receptors [135]. After the administration of this peptide, SHR also showed an improvement in endothelial dysfunction and a reduction in oxidative stress markers with respect to water controls [136]. Another example of a known bioactive peptide is the amino-acid sequence GAOGLOGP, isolated from a leg hydrolysate, which also produced a potent reduction of BP in SHR, reaching the maximum at 6 h post administration [134]. In vitro studies carried out in Caco-2 cells, which are used to simulate the intestinal barrier, showed the energy-independent paracellular transport of the intact peptide [137]. In addition, this peptide produced the release of NO and the activation of eNOS through its phosphorylation at Ser1179 when it was added to bovine aortic endothelial cells, suggesting the potential effect of this peptide in the vascular function [137]. Lastly, VSKRLNGDA is another peptide that has been widely studied to elucidate the mechanisms involved in its antihypertensive effects. This peptide, identified in a blood corpuscle hydrolysate, reduced both SBP and DBP in SHR after its acute administration at 12.5, 25, and 50 mg/kg BW [85]. Interestingly, at 12 h post administration, the dose of 50 mg/kg BW continued exerting its antihypertensive effect, especially noted in SBP (41.8 mmHg). After a prolonged administration to SHR (4 weeks), this peptide at 50 mg/kg BW also showed a potent antihypertensive effect, which was associated with its action on different RAAS system targets, e.g., downregulating the genes encoding renin (Ren1) and Ang-II type-1 receptor (Agtr1b) in kidney. Thus, the peptide would reduce the Ang-II effects on HTN acting in the Ang II-production pathway and the Ang-II receptor involved in the Ang-II effects associated with a BP increase. In addition, VSKRLNGDA also upregulated the expression of adrenoceptor β-3 (Adrb3) and peroxisome proliferator-activated receptor δ (Ppard) in kidneys of treated SHR [85], thus contributing to a BP reduction. Specifically, adrenoceptor β-3 activation has been coupled to an increase in NO levels via eNOS activation [138], and Ppard activation has been associated with a reduction in the proatherogenic, proinflammatory, and oxidative state of hypertensive rats, as well as a restoration of the vascular function and structure [139]. In contrast to the ACEi effect of the five antihypertensive amino-acid sequences isolated from chicken byproduct hydrolysates, the BP-lowering effects of these peptides could not be related to a specific amino-acid profile. Thus, their in vivo effects may be a consequence of the peptide-derived fragments released during the gastrointestinal enzymatic digestion of the chicken peptides, as seen for the amino-acid sequences AVFQHNCQE or VSKRLNGDA [85,135].

4. Conclusions

Chicken slaughterhouse byproducts are a valuable source of ACEi activity and antihypertensive effects. Among these byproducts, chicken feet hydrolysates have been the most studied, showing BP-lowering effects in both animal and human studies. Some of these hydrolysates also exerted antioxidant effects, improved HTN-associated endothelial dysfunction, and reduced ACE activity in different in vivo hypertensive models, which may contribute to their antihypertensive activity. Although some peptides have been identified in these hydrolysates, few studies have validated their in vivo effects.
Taken altogether, chicken byproducts may be excellent candidates for the management of HTN. However, further investigations in clinical studies are needed in order to confirm their beneficial effects observed in hypertensive animal models. This would lead to the possibility to increase the value of these food industry wastes contributing also to the circular economy model of slaughterhouses.

Author Contributions

Conceptualization, F.I.B., A.G.-R. and D.M.; funding acquisition, F.I.B., C.T.-F. and B.M.; supervision, A.G.-R. and D.M.; writing—original draft, F.I.B., E.C., R.A.L.-V., C.T.-F., A.G.-R. and D.M.; writing—review and editing, F.I.B., E.C., C.T.-F., B.M., A.G.-R. and D.M. All authors have read and agreed to the published version of the manuscript.

Funding

This work has been supported by grant numbers PID2020-114608RA-I00 and PDC2021-121625-I00 from Ministerio de Ciencia e Innovación.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Acknowledgments

We want to thank Ana Rivas Velasco for designing the graphical abstract. R.A.L.-V. is a recipient of a predoctoral fellowship from the Universitat Rovira i Virgili (grant number: 2020PMF-PIF-54). F.I.B. is a Serra Húnter Fellow. D.M. thanks the Ministerio de Ciencia e Innovación for grant FJC2020-044585-I (Juan de la Cierva-Formación call).

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. World Health Organization (WHO). Hypertension. Available online: https://www.who.int/news-room/fact-sheets/detail/hypertension (accessed on 11 September 2022).
  2. Hajat, C.; Stein, E. The global burden of multiple chronic conditions: A narrative review. Prev. Med. Rep. 2018, 12, 284–293. [Google Scholar] [CrossRef] [PubMed]
  3. Mora, L.; Gallego, M.; Toldrá, F. ACEI-inhibitory peptides naturally generated in meat and meat products and their health relevance. Nutrients 2018, 10, 1259. [Google Scholar] [CrossRef]
  4. Rezvankhah, A.; Yarmand, M.S.; Ghanbarzadeh, B.; Mirzaee, H. Generation of bioactive peptides from lentil protein: Degree of hydrolysis, antioxidant activity, phenol content, ACE-inhibitory activity, molecular weight, sensory, and functional properties. J. Food Meas. Charact. 2021, 15, 5021–5035. [Google Scholar] [CrossRef]
  5. Margalef, M.; Bravo, F.I.; Arola-Arnal, A.; Muguerza, B. Natural angiotensin converting enzyme (ACE) inhibitors with antihypetensive properties. In Natural Products Targeting Clinically Relevant Enzymes; Andrade, P., Valentao, P., Pereira, D.M., Eds.; Wiley-VCH Verlag GmbH & Co.: Weinheim, Germany, 2017; pp. 45–67. [Google Scholar]
  6. Ajeigbe, O.F.; Ademosun, A.O.; Oboh, G. Relieving the tension in hypertension: Food–drug interactions and anti-hypertensive mechanisms of food bioactive compounds. J. Food Biochem. 2021, 45, e13317. [Google Scholar] [CrossRef] [PubMed]
  7. López-Fernández-Sobrino, R.; Torres-Fuentes, C.; Bravo, F.I.; Muguerza, B. Winery by-products as a valuable source for natural antihypertensive agents. Crit. Rev. Food Sci. Nutr. 2022, 1–14. [Google Scholar] [CrossRef] [PubMed]
  8. Bechaux, J.; Gatellier, P.; Le Page, J.-F.; Drillet, Y.; Sante-Lhoutellier, V. A comprehensive review of bioactive peptides obtained from animal byproducts and their applications. Food Funct. 2019, 10, 6244–6266. [Google Scholar] [CrossRef]
  9. Le Gouic, A.V.; Harnedy, P.A.; FitzGerald, R.J. Bioactive peptides from fish protein by-products. In Bioactive Molecules in Food; Reference Series in Phytochemistry; Mérillon, J., Ramawat, K., Eds.; Springer: Cham, Switzerland, 2018; pp. 1–35. [Google Scholar]
  10. Mora, L.; Reig, M.; Toldrá, F. Bioactive peptides generated from meat industry by-products. Food Res. Int. 2014, 65, 344–349. [Google Scholar] [CrossRef]
  11. Lafarga, T.; Hayes, M. Bioactive protein hydrolysates in the functional food ingredient industry: Overcoming current challenges. Food Rev. Int. 2017, 33, 217–246. [Google Scholar] [CrossRef]
  12. Kanani, F.; Heidari, M.D.; Gilroyed, B.H.; Pelletier, N. Waste valorization technology options for the egg and broiler industries: A review and recommendations. J. Clean. Prod. 2020, 262, 121129. [Google Scholar] [CrossRef]
  13. Food and Agriculture Organization of the United Nations. Gateway to poultry production and products. In Animal Welfare; Food and Agriculture Organization of the United Nations: Rome, Italy, 2022. [Google Scholar]
  14. Valta, K.; Damala, P.; Orli, E.; Papadaskalopoulou, C.; Moustakas, K.; Malamis, D.; Loizidou, M. Valorisation opportunities related to wastewater and animal by-products exploitation by the Greek slaughtering industry: Current status and future potentials. Waste Biomass Valorization 2015, 6, 927–945. [Google Scholar] [CrossRef]
  15. Adler, S.A.; Slizyte, R.; Honkapää, K.; Løes, A.K. In vitro pepsin digestibility and amino acid composition in soluble and residual fractions of hydrolyzed chicken feathers. Poult. Sci. 2018, 97, 3343–3357. [Google Scholar] [CrossRef] [PubMed]
  16. Araújo, Í.B.S.; Lima, D.A.S.; Pereira, S.F.; Madruga, M.S. Quality of low-fat chicken sausages with added chicken feet collagen. Poult. Sci. 2019, 98, 1064–1074. [Google Scholar] [CrossRef]
  17. Fu, Y.; Therkildsen, M.; Aluko, R.E.; Lametsch, R. Exploration of collagen recovered from animal by-products as a precursor of bioactive peptides: Successes and challenges. Crit. Rev. Food Sci. Nutr. 2019, 59, 2011–2027. [Google Scholar] [CrossRef] [PubMed]
  18. Cao, S.; Wang, Y.; Hao, Y.; Zhang, W.; Zhou, G. Antihypertensive effects in vitro and in vivo of novel angiotensin-converting enzyme inhibitory peptides from bovine bone gelatin hydrolysate. J. Agric. Food Chem. 2020, 68, 759–768. [Google Scholar] [CrossRef]
  19. Cao, C.; Xiao, Z.; Tong, H.; Liu, Y.; Wu, Y.; Ge, C. Oral intake of chicken bone collagen peptides anti-skin aging in mice by regulating collagen degradation and synthesis, inhibiting inflammation and activating lysosomes. Nutrients 2022, 14, 1622. [Google Scholar] [CrossRef] [PubMed]
  20. Zhuang, Y.; Sun, L.; Zhang, Y.; Liu, G. Antihypertensive effect of long-term oral administration of Jellyfish (Rhopilema esculentum) collagen peptides on renovascular hypertension. Mar. Drugs 2012, 10, 417–426. [Google Scholar] [CrossRef] [PubMed]
  21. Cai, S.; Pan, N.; Xu, M.; Su, Y.; Qiao, K.; Chen, B.; Zheng, B.; Xiao, M.; Liu, Z. ACE inhibitory peptide from skin collagen hydrolysate of Takifugu bimaculatus as potential for protecting HUVECs injury. Mar. Drugs 2021, 19, 655. [Google Scholar] [CrossRef] [PubMed]
  22. Bravo, F.I.; Mas-Capdevila, A.; Margalef, M.; Arola-Arnal, A.; Muguerza, B. Novel antihypertensive peptides derived from chicken foot proteins. Mol. Nutr. Food Res. 2019, 63, 1801176. [Google Scholar] [CrossRef]
  23. Bravo, F.I.; Mas-Capdevila, A.; López-Fernández-Sobrino, R.; Torres-Fuentes, C.; Mulero, M.; Alcaide-Hidalgo, J.M.; Muguerza, B. Identification of novel antihypertensive peptides from wine lees hydrolysate. Food Chem. 2022, 366, 130690. [Google Scholar] [CrossRef]
  24. Torres-Fuentes, C.; Suárez, M.; Aragonès, G.; Mulero, M.; Ávila-Román, J.; Arola-Arnal, A.; Salvadó, M.J.; Arola, L.; Bravo, F.I.; Muguerza, B. Cardioprotective properties of phenolic compounds: A role for biological rhythms. Mol. Nutr. Food Res. 2022, 66, 2100990. [Google Scholar] [CrossRef] [PubMed]
  25. Chen, R.; Suchard, M.A.; Krumholz, H.M.; Schuemie, M.J.; Shea, S.; Duke, J.; Pratt, N.; Reich, C.G.; Madigan, D.; You, S.C.; et al. Comparative first-line effectiveness and safety of ACE (angiotensin-converting enzyme) inhibitors and angiotensin receptor blockers: A multinational cohort study. Hypertension 2021, 78, 591–603. [Google Scholar] [CrossRef] [PubMed]
  26. Laca, A.; Laca, A.; Diaz, M. Environmental impact of poultry farming and egg production. In Environmental Impact of Agro-Food Industry and Food Consumption; Charis, M.G., Ed.; Academic Press: Cambridge, MA, USA, 2021; pp. 81–100. [Google Scholar]
  27. Li, Y.; Arulnathan, V.; Heidari, M.D.; Pelletier, N. Design considerations for net zero energy buildings for intensive, confined poultry production: A review of current insights, knowledge gaps, and future directions. Renew. Sustain. Energy Rev. 2022, 154, 111874. [Google Scholar] [CrossRef]
  28. Shahbandeh, M. Global Chicken Meat Production 2021 & 2022, by Selected Country. Available online: https://www.statista.com/statistics/237597/leading-10-countries-worldwide-in-poultry-meat-production-in-2007/ (accessed on 10 December 2022).
  29. Food and Agriculture Organization of the United Nations. Poultry Development Review; FAO: Rome, Italy, 2013. [Google Scholar]
  30. Izydorczyk, G.; Mikula, K.; Skrzypczak, D.; Witek-Krowiak, A.; Mironiuk, M.; Furman, K.; Gramza, M.; Moustakas, K.; Chojnacka, K. Valorization of poultry slaughterhouse waste for fertilizer purposes as an alternative for thermal utilization methods. J. Hazard. Mater. 2022, 424, 127328. [Google Scholar] [CrossRef] [PubMed]
  31. Chiarelotto, M.; Restrepo, J.C.P.S.; Lorin, H.E.F.; Damaceno, F.M. Composting organic waste from the broiler production chain: A perspective for the circular economy. J. Clean. Prod. 2021, 329, 129717. [Google Scholar] [CrossRef]
  32. Arshad, M.; Bano, I.; Khan, N.; Shahzad, M.I.; Younus, M.; Abbas, M.; Iqbal, M. Electricity generation from biogas of poultry waste: An assessment of potential and feasibility in Pakistan. Renew. Sustain. Energy Rev. 2018, 81, 1241–1246. [Google Scholar] [CrossRef]
  33. Siddiki, S.Y.A.; Uddin, M.N.; Mofijur, M.; Fattah, I.M.R.; Ong, H.C.; Lam, S.S.; Kumar, P.S.; Ahmed, S.F. Theoretical calculation of biogas production and greenhouse gas emission reduction potential of livestock, poultry and slaughterhouse waste in Bangladesh. J. Environ. Chem. Eng. 2021, 9, 105204. [Google Scholar] [CrossRef]
  34. Mi, X.; Li, W.; Xu, H.; Mu, B.; Chang, Y.; Yang, Y. Transferring feather wastes to ductile keratin filaments towards a sustainable poultry industry. Waste Manag. 2020, 115, 65–73. [Google Scholar] [CrossRef] [PubMed]
  35. Casanova-Martí, À.; Bravo, F.I.; Serrano, J.; Ardévol, A.; Pinent, M.; Muguerza, B. Antihyperglycemic effect of a chicken feet hydrolysate: Via the incretin system: DPP-IV-inhibitory activity and GLP-1 release stimulation. Food Funct. 2019, 10, 4062–4070. [Google Scholar] [CrossRef]
  36. Romero-Garay, M.G.; Montalvo-González, E.; Hernández-González, C.; Soto-Domínguez, A.; Becerra-Verdín, E.M.; De Lourdes García-Magaña, M. Bioactivity of peptides obtained from poultry by-products: A review. Food Chem. 2022, 13, 100181. [Google Scholar] [CrossRef]
  37. Nagal, S.; Jain, P.C. Feather degradation by strains of Bacillus isolated from decomposing feathers. Brazilian J. Microbiol. 2010, 41, 196–200. [Google Scholar]
  38. Fakhfakh, N.; Ktari, N.; Haddar, A.; Mnif, I.H.; Dahmen, I.; Nasri, M. Total solubilisation of the chicken feathers by fermentation with a keratinolytic bacterium, Bacillus pumilus A1, and the production of protein hydrolysate with high antioxidative activity. Proc. Biochem. 2011, 46, 1731–1737. [Google Scholar] [CrossRef]
  39. Sinkiewicz, I.; Śliwińska, A.; Staroszczyk, H.; Kołodziejska, I. Alternative methods of preparation of soluble keratin from chicken feathers. Waste Biomass Valorization 2017, 8, 1043–1048. [Google Scholar] [CrossRef]
  40. Callegaro, K.; Brandelli, A.; Daroit, D.J. Beyond plucking: Feathers bioprocessing into valuable protein hydrolysates. Waste Manag. 2019, 95, 399–415. [Google Scholar] [CrossRef] [PubMed]
  41. Alahyaribeik, S.; Nazarpour, M.; Tabandeh, F.; Honarbakhsh, S.; Sharifi, S.D. Effects of bioactive peptides derived from feather keratin on plasma cholesterol level, lipid oxidation of meat, and performance of broiler chicks. Trop. Anim. Health Prod. 2022, 54, 271. [Google Scholar] [CrossRef]
  42. Kelly, L.M.; Alworth, L.C. Techniques for collecting blood from the domestic chicken. Lab Anim. 2013, 42, 359–361. [Google Scholar] [CrossRef] [PubMed]
  43. Sorapukdee, S.; Narunatsopanon, S. Comparative study on compositions and functional properties of porcine, chicken and duck blood. Korean J. Food Sci. Anim. Resour. 2017, 37, 228–241. [Google Scholar] [CrossRef]
  44. Cheng, F.Y.; Lai, I.C.; Lin, L.C.; Sakata, R. The in vitro antioxidant properties of alcalase hydrolysate prepared from silkie fowl (Gallus gallus) blood protein. Anim. Sci. J. 2016, 87, 921–928. [Google Scholar] [CrossRef]
  45. Zheng, Z.; Si, D.; Ahmad, B.; Li, Z.; Zhang, R. A novel antioxidative peptide derived from chicken blood corpuscle hydrolysate. Food Res. Int. 2018, 106, 410–419. [Google Scholar] [CrossRef] [PubMed]
  46. Cansu, Ü.; Boran, G. Optimization of a multi-step procedure for isolation of chicken bone collagen. Korean J. Food Sci. Anim. Resour. 2015, 35, 431–440. [Google Scholar] [CrossRef] [PubMed]
  47. Polyanskikh, S.V.; Danyliv, M.M.; Dubrovina, U.R.; Ozherelyeva, O.N.; Vasilenko, O.A. The technology of dehydrated soup base from poultry meat and bone residue. In Proceedings of the IOP Conference Series: Materials Science and Engineering, Barnaul, Russia, 26–27 June 2020; IOP Publishing Ltd.: Bristol, UK, 2020; Volume 941. [Google Scholar]
  48. Stiborova, H.; Kronusova, O.; Kastanek, P.; Brazdova, L.; Lovecka, P.; Jiru, M.; Belkova, B.; Poustka, J.; Stranska, M.; Hajslova, J.; et al. Waste products from the poultry industry: A source of high-value dietary supplements. J. Chem. Technol. Biotechnol. 2020, 95, 985–992. [Google Scholar] [CrossRef]
  49. Pramualkijja, T.; Pirak, T.; Euston, S.R. Valorization of chicken slaughterhouse by-products: Production and properties of chicken trachea hydrolysates using commercial proteases. Int. J. Food Prop. 2021, 24, 1642–1657. [Google Scholar] [CrossRef]
  50. Heydarpour, F.; Amini, B.; Kalantari, S.; Sadraddin; Akbari, A.; Heydarpour, P. Mean percentage of skin and visible fat in 10 chicken carcass weight. Int. J. Poult. Sci. 2006, 6, 43–47. [Google Scholar] [CrossRef]
  51. Nadalian, M.; Kamaruzaman, N.; Yusop, M.S.M.; Babji, A.S.; Yusop, S.M. Isolation, purification and characterization of antioxidative bioactive elastin peptides from poultry skin. Food Sci. Anim. Resour. 2019, 39, 966–979. [Google Scholar] [CrossRef]
  52. Onuh, J.O.; Girgih, A.T.; Aluko, R.E.; Aliani, M. Inhibitions of renin and angiotensin converting enzyme activities by enzymatic chicken skin protein hydrolysates. Food Res. Int. 2013, 53, 260–267. [Google Scholar] [CrossRef]
  53. Gonçalves dos Santos Aguilar, J.; Santos de Souza, A.K.; Soares de Castro, R.J. Enzymatic hydrolysis of chicken viscera to obtain added-value protein hydrolysates with antioxidant and antihypertensive properties. Int. J. Pept. Res. Ther. 2020, 26, 717–725. [Google Scholar] [CrossRef]
  54. Jamdar, S.N.; Rajalakshmi, V.; Sharma, A. Antioxidant and ace inhibitory properties of poultry viscera protein hydrolysate and its peptide fractions. J. Food Biochem. 2012, 36, 494–501. [Google Scholar] [CrossRef]
  55. Mane, S.; Jamdar, S.N. Purification and identification of Ace-inhibitory peptides from poultry viscera protein hydrolysate. J. Food Biochem. 2017, 41, e12275. [Google Scholar] [CrossRef]
  56. Santana, J.C.C.; Gardim, R.B.; Almeida, P.F.; Borini, G.B.; Quispe, A.P.B.; Llanos, S.A.V.; Heredia, J.A.; Zamuner, S.; Gamarra, F.M.C.; Farias, T.M.B.; et al. Valorization of chicken feet by-product of the poultry industry: High qualities of gelatin and biofilm from extraction of collagen. Polymers 2020, 12, 529. [Google Scholar] [CrossRef]
  57. Araújo, Í.B.D.S.; Bezerra, T.K.A.; Nascimento, E.S.D.; Gadelha, C.A.D.A.; Santi-Gadelha, T.; Madruga, M.S. Optimal conditions for obtaining collagen from chicken feet and its characterization. Food Sci. Technol. 2018, 38, 167–173. [Google Scholar] [CrossRef]
  58. Severo da Rosa, C.; Hoelzel, S.C.; Viera, V.B.; Barreto, P.M.; Beirão, L.H. Atividade antioxidante do ácido hialurônico extraído da crista de frango. Ciência Rural 2008, 38, 2593–2698. [Google Scholar] [CrossRef]
  59. Londoño-Zapata, L.; Franco-Cardona, S.; Restrepo-Manotas, S.; Gomez-Narvaez, F.; Suarez-Restrepo, L.; Nuñez-Andrade, H.; Valencia-Araya, P.; Simpson, R.; Vega-Castro, O. Valorization of the by-products of poultry industry (bones) by enzymatic hydrolysis and glycation to obtain antioxidants compounds. Waste Biomass Valorization 2022, 13, 4469–4480. [Google Scholar] [CrossRef]
  60. Cheng, F.-Y.; Liu, Y.-T.; Wan, T.-C.; Lin, L.-C.; Sakata, R. The development of angiotensin I-converting enzyme inhibitor derived from chicken bone protein. Anim. Sci. J. 2008, 79, 122–128. [Google Scholar] [CrossRef]
  61. Kettawan, A.; Sungpuag, P.; Sirichakwal, P.; Chavasit, V. Chicken bone calcium extraction and its application as a food fortificant. Mater. Sci. 2002, 34, 163–180. [Google Scholar]
  62. Tesfaye, T.; Sithole, B.; Ramjugernath, D.; Chunilall, V. Valorisation of chicken feathers: Characterisation of chemical properties. Waste Manag. 2017, 68, 626–635. [Google Scholar] [CrossRef] [PubMed]
  63. Ben Hamad Bouhamed, S.; Krichen, F.; Kechaou, N. Feather protein hydrolysates: A study of physicochemical, functional properties and antioxidant activity. Waste Biomass Valorization 2020, 11, 51–62. [Google Scholar] [CrossRef]
  64. Prajapati, S.; Koirala, S.; Anal, A.K. Bioutilization of chicken feather waste by newly isolated keratinolytic bacteria and conversion into protein hydrolysates with improved functionalities. Appl. Biochem. Biotechnol. 2021, 193, 2497–2515. [Google Scholar] [CrossRef]
  65. da Silva Bambirra Alves, F.E.; Carpiné, D.; Teixeira, G.L.; Goedert, A.C.; de Paula Scheer, A.; Ribani, R.H. Valorization of an abundant slaughterhouse by-product as a source of highly technofunctional and antioxidant protein hydrolysates. Waste Biomass Valorization 2021, 12, 263–279. [Google Scholar] [CrossRef]
  66. Huang, S.-C.; Liu, P.-J. Inhibition of angiotensin I-Converting enzymes by enzymatic hydrolysates from chicken blood. J. Food Drug Anal. 2010, 18, 459–463. [Google Scholar] [CrossRef]
  67. González-Noriega, J.A.; Valenzuela-Melendres, M.; Hernández–Mendoza, A.; Astiazarán-García, H.; Mazorra-Manzano, M.Á.; Peña-Ramos, E.A. Hydrolysates and peptide fractions from pork and chicken skin collagen as pancreatic lipase inhibitors. Food Chem. 2022, 13, 100247. [Google Scholar] [CrossRef] [PubMed]
  68. Choi, Y.S.; Han, D.J.; Choi, J.H.; Hwang, K.E.; Song, D.H.; Kim, H.W.; Kim, Y.B.; Kim, C.J. Effect of chicken skin on the quality characteristics of semi-dried restructured jerky. Poult. Sci. 2016, 95, 1198–1204. [Google Scholar] [CrossRef] [PubMed]
  69. Safar Razavizadeh, R.; Farmani, J.; Motamedzadegan, A. Enzyme-assisted extraction of chicken skin protein hydrolysates and fat: Degree of hydrolysis affects the physicochemical and functional properties. J. Am. Oil Chem. Soc. 2022, 99, 621–632. [Google Scholar] [CrossRef]
  70. Potti, R.; Fahad, M. Extraction and Characterization of Collagen from Broiler Chicken Feet (Gallus gallus domesticus)—Biomolecules from Poultry Waste. J. Pure Appl. Microbiol. 2017, 11, 315–322. [Google Scholar] [CrossRef]
  71. Yuliatmo, R.; Fitriyanto, N.A.; Bachruddin, Z.; Erwanto, Y. Increasing of angiotensin converting enzyme inhibitory derived from Indonesian native chicken leg protein using Bacillus cereus protease enzyme. Int. Food Res. J. 2017, 24, 1799–1804. [Google Scholar]
  72. Hashim, P.; Ridzwan, M.S.M.; Bakar, J. Isolation and characterization of collagen from chicken feet. World Acad. Sci. Eng. Technol. Int. J. Bioeng. Life Sci. 2014, 8, 250–254. [Google Scholar]
  73. Jamdar, S.N.; Harikumar, P. A rapid autolytic method for the preparation of protein hydrolysate from poultry viscera. Bioresour. Technol. 2008, 99, 6934–6940. [Google Scholar] [CrossRef] [PubMed]
  74. Rivera, J.A.; Sebranek, J.G.; Rust, R.E.; Tabatabai, L.B. Composition and protein fractions of different meat by-products used for petfood compared with mechanically separated chicken (MSC). Meat Sci. 2000, 55, 53–59. [Google Scholar] [CrossRef] [PubMed]
  75. Shin, S.; You, S.J.; An, B.K.; Kang, C.W. Study on extraction of mucopolysaccharide-protein containing chondroitin sulfate from chicken keel cartilage. Asian-Australas. J. Anim. Sci. 2006, 19, 601–604. [Google Scholar] [CrossRef]
  76. Ibarz-Blanch, N.; Morales, D.; Calvo, E.; Ros-Medina, L.; Muguerza, B.; Bravo, F.I.; Suárez, M. Role of chrononutrition in the antihypertensive effects of natural bioactive compounds. Nutrients 2022, 14, 1920. [Google Scholar] [CrossRef]
  77. Pueyo, M.E.; Michel, J.-B. Angiotensin II receptors in endothelial cells. Gen. Pharmacol. Vasc. Syst. 1997, 29, 691–696. [Google Scholar] [CrossRef] [PubMed]
  78. Touyz, R.M.; Chen, X.; Tabet, F.; Yao, G.; He, G.; Quinn, M.T.; Pagano, P.J.; Schiffrin, E.L. Expression of a functionally active gp91phox-containing neutrophil-type NAD(P)H oxidase in smooth muscle cells from human resistance arteries. Circ. Res. 2002, 90, 1205–1213. [Google Scholar] [CrossRef]
  79. Rubanyi, G.M.; Vanhoutte, P.M. Superoxide anions and hyperoxia inactivate endothelium-derived relaxing factor. Am. J. Physiol. Circ. Physiol. 1986, 250, H822–H827. [Google Scholar] [CrossRef]
  80. Łuczak, A.; Madej, M.; Kasprzyk, A.; Doroszko, A. Role of the eNOS uncoupling and the nitric oxide metabolic pathway in the pathogenesis of autoimmune rheumatic diseases. Oxid. Med. Cell. Longev. 2020, 2020, 1417981. [Google Scholar] [CrossRef]
  81. Patel, S.; Rauf, A.; Khan, H.; Abu-Izneid, T. Renin-angiotensin-aldosterone (RAAS): The ubiquitous system for homeostasis and pathologies. Biomed. Pharmacother. 2017, 94, 317–325. [Google Scholar] [CrossRef]
  82. Osborn, J.W.; Foss, J.D. Renal nerves and long-term control of arterial pressure. Compr. Physiol. 2017, 7, 263–320. [Google Scholar] [CrossRef]
  83. Watanabe, T.; Barker, T.A.; Berk, B.C. Angiotensin II and the endothelium. Hypertension 2005, 45, 163–169. [Google Scholar] [CrossRef]
  84. Wongngam, W.; Mitani, T.; Katayama, S.; Nakamura, S.; Yongsawatdigul, J. Production and characterization of chicken blood hydrolysate with antihypertensive properties. Poult. Sci. 2020, 99, 5163–5174. [Google Scholar] [CrossRef]
  85. Wongngam, W.; Roytrakul, S.; Mitani, T.; Katayama, S.; Nakamura, S.; Yongsawatdigul, J. Isolation, identification, and in vivo evaluation of the novel antihypertensive peptide, VSKRLNGDA, derived from chicken blood cells. Proc. Biochem. 2022, 115, 169–177. [Google Scholar] [CrossRef]
  86. Gao, D.; Guo, P.; Cao, X.; Ge, L.; Ma, H.; Cheng, H.; Ke, Y.; Chen, S.; Ding, G.; Feng, R.; et al. Improvement of chicken plasma protein hydrolysate angiotensin I-converting enzyme inhibitory activity by optimizing plastein reaction. Food Sci. Nutr. 2020, 8, 2798–2808. [Google Scholar] [CrossRef]
  87. Nikhita, R.; Sachindra, N.M. Optimization of chemical and enzymatic hydrolysis for production of chicken blood protein hydrolysate rich in angiotensin-I converting enzyme inhibitory and antioxidant activity. Poult. Sci. 2021, 100, 101047. [Google Scholar] [CrossRef]
  88. Gao, B.; Zhao, X.-H. Modification of soybean protein hydrolysates by Alcalase-catalyzed plastein reaction and the ACE-inhibitory activity of the modified product In Vitro. Int. J. Food Prop. 2012, 15, 982–996. [Google Scholar] [CrossRef]
  89. Wei, X.; Li, T.-J.; Zhao, X.-H. Coupled neutrase–catalyzed plastein reaction mediated the ACE-inhibitory activity In Vitro of casein hydrolysates prepared by Alcalase. Int. J. Food Prop. 2013, 16, 429–443. [Google Scholar] [CrossRef]
  90. Yamashita, M.; Arai, S.; Tsai, S.-J.; Fujimaki, M. Plastein reaction as a method for enhancing the sulfur-containing amino acid level of soybean protein. J. Agric. Food Chem. 1971, 19, 1151–1154. [Google Scholar] [CrossRef] [PubMed]
  91. Riffel, A.; Daroit, D.J.; Brandelli, A. Nutritional regulation of protease production by the feather-degrading bacterium Chryseobacterium sp. kr6. New Biotechnol. 2011, 28, 153–157. [Google Scholar] [CrossRef]
  92. Cheng, F.Y.; Wan, T.C.; Liu, Y.T.; Lai, K.M.; Lin, L.C.; Sakata, R. A study of in vivo antihypertensive properties of enzymatic hydrolysate from chicken leg bone protein. Anim. Sci. J. 2008, 79, 614–619. [Google Scholar] [CrossRef]
  93. Cheng, F.Y.; Wan, T.C.; Liu, Y.T.; Lai, K.M.; Lin, L.C.; Sakata, R. Attenuating development of cardiovascular hypertrophy with hydrolysate of chicken leg bone protein in spontaneously hypertensive rats. Asian-Australas. J. Anim. Sci. 2008, 21, 732–737. [Google Scholar] [CrossRef]
  94. Kuneš, J.; Vaněčková, I.; Kadlecová, M.; Behuliak, M.; Dobešová, Z.; Zicha, J. Cardiac hypertrophy in hypertension. In Cardiac Adaptations; Springer: New York, NY, USA, 2013; pp. 251–267. [Google Scholar]
  95. Burke, G.L.; Evans, G.W.; Riley, W.A.; Sharrett, A.R.; Howard, G.; Barnes, R.W.; Rosamond, W.; Crow, R.S.; Rautaharju, P.M.; Heiss, G. Arterial wall thickness is associated with prevalent cardiovascular disease in middle-aged adults. Stroke 1995, 26, 386–391. [Google Scholar] [CrossRef] [PubMed]
  96. Corinaldesi, G.; Corinaldesi, C. Arterial Wall Thickness: Marker of Atherosclerosis or Risk Factor for Thrombosis. Blood 2008, 112, 5470. [Google Scholar] [CrossRef]
  97. Nakade, K.; Kamishima, R.; Inoue, Y.; Ahhmed, A.; Kawahara, S.; Nakayama, T.; Maruyama, M.; Numata, M.; Ohta, K.; Aoki, T.; et al. Identification of an antihypertensive peptide derived from chicken bone extract. Anim. Sci. J. 2008, 79, 710–715. [Google Scholar] [CrossRef]
  98. Alencar-Bezerra, T.K.; Gomes de Lacerda, J.T.J.; Ramos-Salu, B.; Vilela-Oliva, M.L.; Juliano, M.A.; Bertoldo-Pacheco, M.T.; Suely-Madruga, M. Identification of angiotensin I-converting enzyme-inhibitory and anticoagulant peptides from enzymatic hydrolysates of chicken combs and wattles. J. Med. Food 2019, 22, 1294–1300. [Google Scholar] [CrossRef]
  99. Mas-Capdevila, A.; Pons, Z.; Aleixandre, A.; Bravo, F.I.; Muguerza, B. Dose-related antihypertensive properties and the corresponding mechanisms of a chicken foot hydrolysate in hypertensive rats. Nutrients 2018, 10, 1295. [Google Scholar] [CrossRef]
  100. Mas-Capdevila, A.; Iglesias-Carres, L.; Arola-Arnal, A.; Suarez, M.; Muguerza, B.; Bravo, F.I. Long-term administration of protein hydrolysate from chicken feet induces antihypertensive effect and confers vasoprotective pattern in diet-induced hypertensive rats. J. Funct. Foods 2019, 55, 28–35. [Google Scholar] [CrossRef]
  101. Saiga, A.; Iwai, K.; Hayakawa, T.; Takahata, Y.; Kitamura, S.; Nishimura, T.; Morimatsu, F. Angiotensin I-converting enzyme-inhibitory peptides obtained from chicken collagen hydrolysate. J. Agric. Food Chem. 2008, 56, 9586–9591. [Google Scholar] [CrossRef]
  102. Zhang, Y.; Kouguchi, T.; Shimizu, M.; Ohmori, T.; Takahata, Y.; Morimatsu, F. Chicken collagen hydrolysate protects rats from hypertension and cardiovascular damage. J. Med. Food 2010, 13, 399–405. [Google Scholar] [CrossRef]
  103. Saiga-Egusa, A.; Koji, I.; Hayakawa, T.; Takahata, Y.; Morimatsu, F. Antihypertensive effects and endothelial progenitor cell activation by intake of chicken collagen hydrolysate in pre- and mild-hypertension. Biosci. Biotechnol. Biochem. 2009, 73, 422–424. [Google Scholar] [CrossRef]
  104. Kouguchi, T.; Ohmori, T.; Shimizu, M.; Takahata, Y.; Maeyama, Y.; Suzuki, T.; Morimatsu, F.; Tanabe, S. Effects of a chicken collagen hydrolysate on the circulation system in subjects with mild hypertension or high-normal blood pressure. Biosci. Biotechnol. Biochem. 2013, 77, 691–696. [Google Scholar] [CrossRef]
  105. Fontoura, R.; Daroit, D.J.; Correa, A.P.F.; Meira, S.M.M.; Mosquera, M.; Brandelli, A. Production of feather hydrolysates with antioxidant, angiotensin-I converting enzyme- and dipeptidyl peptidase-IV-inhibitory activities. New Biotechnol. 2014, 31, 506–513. [Google Scholar] [CrossRef] [PubMed]
  106. Onuh, J.O.; Girgih, A.T.; Malomo, S.A.; Aluko, R.E.; Aliani, M. Kinetics of in vitro renin and angiotensin converting enzyme inhibition by chicken skin protein hydrolysates and their blood pressure lowering effects in spontaneously hypertensive rats. J. Funct. Foods 2015, 14, 133–143. [Google Scholar] [CrossRef]
  107. Onuh, J.O.; Girgih, A.T.; Nwachukwu, I.; Ievari-Shariati, S.; Raj, P.; Netticadan, T.; Aluko, R.E.; Aliani, M. A metabolomics approach for investigating urinary and plasma changes in spontaneously hypertensive rats (SHR) fed with chicken skin protein hydrolysates diets. J. Funct. Foods 2016, 22, 20–33. [Google Scholar] [CrossRef]
  108. Chen, Y.H.; Liu, Y.H.; Yang, Y.H.; Feng, H.H.; Chang, C.T.; Chen, C.C. Antihypertensive effect of an enzymatic hydrolysate of chicken essence residues. Food Sci. Technol. Res. 2002, 8, 144–147. [Google Scholar] [CrossRef]
  109. Chakka, A.K.; Ramanatikara, J.; Zituji, S.P.; Pedda, M.S.; Narayan, B. In-vivo anti-anaemic effects of bioactive compounds prepared from chicken liver using biotechnological tools. Waste Biomass Valorization 2021, 12, 6699–6708. [Google Scholar] [CrossRef]
  110. Grassi, D.; Desideri, G.; Ferri, C. Cardiovascular risk and endothelial dysfunction: The preferential route for atherosclerosis. Curr. Pharm. Biotechnol. 2011, 12, 1343–1353. [Google Scholar] [CrossRef] [PubMed]
  111. Incalza, M.A.; D’Oria, R.; Natalicchio, A.; Perrini, S.; Laviola, L.; Giorgino, F. Oxidative stress and reactive oxygen species in endothelial dysfunction associated with cardiovascular and metabolic diseases. Vascul. Pharmacol. 2018, 100, 1–19. [Google Scholar] [CrossRef]
  112. Sun, H.-J.; Wu, Z.-Y.; Nie, X.-W.; Bian, J.-S. Role of endothelial dysfunction in cardiovascular diseases: The link between inflammation and hydrogen sulfide. Front. Pharmacol. 2020, 10, 1568. [Google Scholar] [CrossRef] [PubMed]
  113. Hadi, H.A.R.; Carr, C.S.; Al Suwaidi, J. Endothelial dysfunction: Cardiovascular risk factors, therapy, and outcome. Vasc. Health Risk Manag. 2005, 1, 183–198. [Google Scholar] [PubMed]
  114. Yanai, H.; Tomono, Y.; Ito, K.; Furutani, N.; Yoshida, H.; Tada, N. The underlying mechanisms for development of hypertension in the metabolic syndrome. Nutr. J. 2008, 7, 10. [Google Scholar] [CrossRef]
  115. Lawson, C.; Wolf, S. ICAM-1 signaling in endothelial cells. Pharmacol. Rep. 2009, 61, 22–32. [Google Scholar] [CrossRef]
  116. Hwang, S.-J.; Ballantyne, C.M.; Sharrett, A.R.; Smith, L.C.; Davis, C.E.; Gotto, A.M.; Boerwinkle, E. Circulating Adhesion Molecules VCAM-1, ICAM-1, and E-selectin in Carotid Atherosclerosis and Incident Coronary Heart Disease Cases. Circulation 1997, 96, 4219–4225. [Google Scholar] [CrossRef]
  117. Luc, G.; Arveiler, D.; Evans, A.; Amouyel, P.; Ferrieres, J.; Bard, J.-M.; Elkhalil, L.; Fruchart, J.-C.; Ducimetiere, P. Circulating soluble adhesion molecules ICAM-1 and VCAM-1 and incident coronary heart disease: The PRIME Study. Atherosclerosis 2003, 170, 169–176. [Google Scholar] [CrossRef]
  118. Gross, M.D.; Bielinski, S.J.; Suarez-Lopez, J.R.; Reiner, A.P.; Bailey, K.; Thyagarajan, B.; Carr, J.J.; Duprez, D.A.; Jacobs, D.R. Circulating soluble intercellular adhesion molecule 1 and subclinical atherosclerosis: The coronarya artery risk development in young adults study. Clin. Chem. 2012, 58, 411–420. [Google Scholar] [CrossRef] [PubMed]
  119. Springer, T.A. Traffic signals on endothelium for lymphocyte recirculation and leukocyte emigration. Annu. Rev. Physiol. 1995, 57, 827–872. [Google Scholar] [CrossRef]
  120. Zhang, M.; Malik, A.B.; Rehman, J. Endothelial progenitor cells and vascular repair. Curr. Opin. Hematol. 2014, 21, 224–228. [Google Scholar] [CrossRef]
  121. Tomiyama, H.; Ohkuma, T.; Ninomiya, T.; Nakano, H.; Matsumoto, C.; Avolio, A.; Kohro, T.; Higashi, Y.; Maruhashi, T.; Takase, B.; et al. Brachial-ankle pulse wave velocity versus its stiffness index β-transformed value as risk marker for cardiovascular disease. J. Am. Heart Assoc. 2019, 8, e013004. [Google Scholar] [CrossRef]
  122. Zarzuelo, M.J.; López-Sepúlveda, R.; Sánchez, M.; Romero, M.; Gómez-Guzmán, M.; Ungvary, Z.; Pérez-Vizcaíno, F.; Jiménez, R.; Duarte, J. SIRT1 inhibits NADPH oxidase activation and protects endothelial function in the rat aorta: Implications for vascular aging. Biochem. Pharmacol. 2013, 85, 1288–1296. [Google Scholar] [CrossRef] [PubMed]
  123. Mattagajasingh, I.; Kim, C.-S.; Naqvi, A.; Yamamori, T.; Hoffman, T.A.; Jung, S.-B.; DeRicco, J.; Kasuno, K.; Irani, K. SIRT1 promotes endothelium-dependent vascular relaxation by activating endothelial nitric oxide synthase. Proc. Natl. Acad. Sci. USA 2007, 104, 14855–14860. [Google Scholar] [CrossRef] [PubMed]
  124. Martín-González, M.Z.; Palacios-Jordan, H.; Ibars, M.; Ardid-Ruiz, A.; Gibert-Ramos, A.; Rodríguez, M.A.; Suárez, M.; Muguerza, B.; Aragonès, G. A novel dietary multifunctional ingredient reduces body weight and improves leptin sensitivity in cafeteria diet-fed rats. J. Funct. Foods 2020, 73, 104141. [Google Scholar] [CrossRef]
  125. Martín-González, M.Z.; Palacios-Jordan, H.; Mas-Capdevila, A.; Rodríguez, M.A.; Bravo, F.I.; Muguerza, B.; Aragonès, G. A multifunctional ingredient for the management of metabolic syndrome in cafeteria diet-fed rats. Food Funct. 2021, 12, 815–824. [Google Scholar] [CrossRef]
  126. Gibert-Ramos, A.; Martín-González, M.Z.; Crescenti, A.; Salvadó, M.J. A mix of natural bioactive compounds reduces fat accumulation and modulates gene expression in the adipose tissue of obese rats fed a cafeteria diet. Nutrients 2020, 12, 3251. [Google Scholar] [CrossRef]
  127. Sanchez-Lozada, L.G.; Rodriguez-Iturbe, B.; Kelley, E.E.; Nakagawa, T.; Madero, M.; Feig, D.I.; Borghi, C.; Piani, F.; Cara-Fuentes, G.; Bjornstad, P.; et al. Uric Acid and Hypertension: An Update With Recommendations. Am. J. Hypertens. 2020, 33, 583–594. [Google Scholar] [CrossRef]
  128. Tucker, J.M.; Townsend, D.M. Alpha-tocopherol: Roles in prevention and therapy of human disease. Biomed. Pharmacother. 2005, 59, 380–387. [Google Scholar] [CrossRef]
  129. Sarbon, N.; Howell, N.; Wan Ahmad, W.A.N. Angiotensin-I converting enzyme (ACE) inhibitory peptides from chicken skin gelatin hydrolysate and its antihypertensive effect in spontaneously hypertensive rats. Int. Food Res. J. 2019, 26, 903–911. [Google Scholar]
  130. Kapel, R.; Rahhou, E.; Lecouturier, D.; Guillochon, D.; Dhulster, P. Characterization of an antihypertensive peptide from an Alfalfa white protein hydrolysate produced by a continuous enzymatic membrane reactor. Proc. Biochem. 2006, 41, 1961–1966. [Google Scholar] [CrossRef]
  131. Murray, B.; FitzGerald, R. Angiotensin converting enzyme inhibitory peptides derived from food proteins: Biochemistry, bioactivity and production. Curr. Pharm. Des. 2007, 13, 773–791. [Google Scholar] [CrossRef] [PubMed]
  132. Li, G.-H.; Le, G.-W.; Shi, Y.-H.; Shrestha, S. Angiotensin I–converting enzyme inhibitory peptides derived from food proteins and their physiological and pharmacological effects. Nutr. Res. 2004, 24, 469–486. [Google Scholar] [CrossRef]
  133. Iwai, K.; Saiga-Egusa, A.; Hayakawa, T.; Shimizu, M.; Takahata, Y.; Morimatsu, F. An angiotensin I-converting enzyme (ACE)-inhibitory peptide derived from chicken collagen hydrolysate lowers blood pressure in spontaneously hypertensive rats. J. Jpn. Soc. Food Sci. Technol. 2008, 55, 602–605. [Google Scholar] [CrossRef]
  134. Iwai, K.; Zhang, Y.; Kouguchi, T.; Saiga-Egusa, A.; Shimizu, M.; Ohmori, T.; Takahata, Y.; Morimatsu, F. Blood concentration of food-derived peptides following oral intake of chicken collagen hydrolysate and its angiotensin-converting enzyme inhibitory activity in healthy volunteers. J. Jpn. Soc. Food Sci. Technol. 2009, 56, 326–330. [Google Scholar] [CrossRef]
  135. Mas-Capdevila, A.; Iglesias-Carres, L.; Arola-Arnal, A.; Aragonès, G.; Muguerza, B.; Bravo, F.I. Implication of opioid receptors in the antihypertensive effect of a novel chicken foot-derived peptide. Biomolecules 2020, 10, 992. [Google Scholar] [CrossRef] [PubMed]
  136. Mas-Capdevila, A.; Iglesias-Carres, L.; Arola-Arnal, A.; Aragonès, G.; Aleixandre, A.; Bravo, F.I.; Muguerza, B. Evidence that nitric oxide is involved in the blood pressure lowering effect of the peptide AVFQHNCQE in spontaneously hypertensive rats. Nutrients 2019, 11, 225. [Google Scholar] [CrossRef] [PubMed]
  137. Shimizu, K.; Sato, M.; Zhang, Y.; Kouguchi, T.; Takahata, Y.; Morimatsu, F.; Shimizu, M. The bioavailable octapeptide Gly-Ala-Hyp-Gly-Leu-Hyp-Gly-Pro stimulates nitric oxide synthesis in vascular endothelial cells. J. Agric. Food Chem. 2010, 58, 6960–6965. [Google Scholar] [CrossRef]
  138. Galougahi, K.K.; Liu, C.; Garcia, A.; Gentile, C.; Fry, N.A.; Hamilton, E.J.; Hawkins, C.L.; Figtree, G.A. β3 adrenergic stimulation restores nitric oxide/redox balance and enhances endothelial function in hyperglycemia. J. Am. Heart Assoc. 2016, 5, e002824. [Google Scholar] [CrossRef] [PubMed]
  139. Zarzuelo, M.J.; Jiménez, R.; Galindo, P.; Sánchez, M.; Nieto, A.; Romero, M.; Quintela, A.M.; López-Sepúlveda, R.; Gómez-Guzmán, M.; Bailón, E.; et al. Antihypertensive Effects of Peroxisome Proliferator-Activated Receptor-β Activation in Spontaneously Hypertensive Rats. Hypertension 2011, 58, 733–743. [Google Scholar] [CrossRef]
Table 1. Composition of chicken byproducts (% wet basis).
Table 1. Composition of chicken byproducts (% wet basis).
Chicken
By-Products
Protein
(%)
Ash
(%)
Moisture
(%)
Fat
(%)
Carbohydrate
(%)
Mineral
(%)
Fiber
(%)
References
Bones15.6–23.5811.80–12.3553.2–57.518.4–9.52114.7–15.9-[46,59,60,61]
Feathers80–85.310.69–0.832.03–10.062–3.92-1.2<1[38,62,63,64]
Blood14.46–20.550.81–3.7475–820.033–1.690.363--[43,65,66]
Skin8.5–15.210.64–0.943.70–54.2231.44–41.4---[67,68,69]
Feet/legs18.10–22.917.94–8.1658.02–65.083.90–6.2---[70,71,72]
Viscera11.2–12.81.1–1.7669.64–76.56.9–16.93---[73,74]
Trachea *69.71--16.53---[49]
Crest--84----[58]
Cartilages11.781.2182.850.293.87--[75]
* % (g/100 g dry byproduct).
Table 3. Angiotensin-converting enzyme-inhibitory and antihypertensive activities shown by the peptides identified in hydrolysates obtained from chicken byproducts.
Table 3. Angiotensin-converting enzyme-inhibitory and antihypertensive activities shown by the peptides identified in hydrolysates obtained from chicken byproducts.
By-ProductHydrolisis ConditionsAmino Acid SequenceNative ProteinACEi Activity (µM)ModelDose (mg/kg BW)PeriodEffect on BPMechanismReference
FeetProtamex® 0.4 AU/g prot, 2 h, 50 °C, pH 7.0LGIHPDWQFVne>137.6 [22]
LSETVVne>515.4
LSGPVKFne80.9
AVKILPne7.1
VRWEPAPGPVne>150.0
VGKPGARAPmYne29.7
QVGPLIGRYCGne11.0SHR10Single↓ SBP (10.9 mmHg, 6 h pa)
AVFQHNCQEne44.8SHR10Single↓ SBP (25.1 mmHg, 6 h pa)
↓ DBP (17.7 mmHg, 2 h pa)
Implication of NO
Nox4
Et-1
↑ GSH levelsActivation opiod receptors
[22,135,136]
Blood corpuscleAlcalase® 4% enzyme, 6 h, 51.1 °C, pH 8.0VNEDSGPFEDSTGATSChain I, cytochrome Bc1 complex from chicken with designed inhibitor bound35.56 [85]
VSKRLNGDAChain B, R-state form of chicken hemoglobin D34.48SHR12.5, 25 and 50Single↓ SBP
↓ DBP
SHR50Daily for 4 weeks↓ SBP (83.1 mmHg)
↓ DBP
↓ Ren1
↓ Agtr1b
↑ Adrb3
↑ Ppard
MMTCLAGMPNLFChain C, cytochrome Bc1 complex from chicken40.64
ELNNLLNPALFFSAChain D, chicken cytochrome Bc1 complex inhibited by an iodinated analog of the polyketide crocacin-d34.48
ARCGSHCDYIKHWPChain B, chicken cytochrome Bc1 complex inhibited by an iodinated analog of the polyketide crocacin-d29.17
NVSTVLTMKKFChain A, R-state form of chicken hemoglobin D40.64
CSFDVPTGWASWTPLChain A, two fibronectin type iii domain segment from chicken tenascin39.24
FPLCTPAFMTVChain I, cytochrome Bc1 complex from chicken29.17
NCVWSGSTFGNPRYSIGChain A, crystal structure of native chicken fibrinogen31.60
VMKKSSRCTGFERLAGFNRNFEFAChain G, chicken cytochrome Bc1 complex inhibited by an iodinated analog of the polyketide crocacin-d51.73
Leg with clawsAspergillus oryzae protease (0.1%) + Protease FP, 24 h, 50 °C, pH 7.0GAOGLOGPCollagen α129.4SHR4.5 mg/kg BWSingle↓SBP (~38 mmHg, 6 h pa) [101,133]
Bovine aortic endothelial cells (BAECs)10 µM ↑ NO levels
↑ Phosphorylation of eNOS at Ser1179
[137]
GAOGPAGPGGIOGERGCollagen α245.6 [101]
GLOGSRGERGLOGCollagen α260.8
GIOGERGPVGPSGCollagen α243.4
BonePepsin 1:100 (w/w), 6 h, 36 °C, pH 2.0YYRAg heavy chain V region33.9SHR10 mg/kgSingle↓ SBP (~18 mmH, 3–6 h pa) [97]
Combs and WattlesAlcalase 5% (E/S ratio), 4 h, 50 °C, pH 8.0APGLPGPR 53 [98]
Piro-GPPGPT 88
FPGPPGP 38
Viscera Autolytic degradation of tissue protein (6 h, 58 °C, pH 2.8)ARIYHPeripheral myelin protein 22a13.6 [55]
LRKGNLEBasic leucine zipper and W2 domain-containing protein 210.8 ± 0.5
RVWCPNADH dehydrogenase [ubiquinone] 1 alpha subcomplex assembly factor 4 isoform X27.5 ± 0.3
Abbreviations: ACEi activity: angiotensin-converting enzyme inhibitory activity; Adrb3: adrenoceptor beta 3 gene; Agtr1b: angiotensin II receptor type 1 b gene; BP: blood pressure; BW: body weight; DBP: diastolic blood pressure; eNOS: endothelial nitric oxide synthase; Et-1: endothelin 1 gene; E/S: enzyme/substrate; GSH: reduced glutathione; ne: not specified; NO: nitric oxide; Nox4: NADPH oxidase subunit 4 gene; pa: post administration; Ppard: peroxisome proliferator-activated receptor delta gene; SBP: systolic blood pressure; SHR: spontaneously hypertensive rats; Ren1: renin gene. ↑ and ↓ indicate increase or decrease of a parameter, respectively.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Bravo, F.I.; Calvo, E.; López-Villalba, R.A.; Torres-Fuentes, C.; Muguerza, B.; García-Ruiz, A.; Morales, D. Valorization of Chicken Slaughterhouse Byproducts to Obtain Antihypertensive Peptides. Nutrients 2023, 15, 457. https://doi.org/10.3390/nu15020457

AMA Style

Bravo FI, Calvo E, López-Villalba RA, Torres-Fuentes C, Muguerza B, García-Ruiz A, Morales D. Valorization of Chicken Slaughterhouse Byproducts to Obtain Antihypertensive Peptides. Nutrients. 2023; 15(2):457. https://doi.org/10.3390/nu15020457

Chicago/Turabian Style

Bravo, Francisca Isabel, Enrique Calvo, Rafael A. López-Villalba, Cristina Torres-Fuentes, Begoña Muguerza, Almudena García-Ruiz, and Diego Morales. 2023. "Valorization of Chicken Slaughterhouse Byproducts to Obtain Antihypertensive Peptides" Nutrients 15, no. 2: 457. https://doi.org/10.3390/nu15020457

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop