Search Results (234)

Ruminant livestock production plays a crucial role in the agricultural systems of Sub-Saharan Africa, significantly supporting rural livelihoods through income generation, improved nutrition, and employment opportunities. Despite its importance, the sector continues to face substantial challenges, such as low feed quality, seasonal feed shortages, and climate-related stresses, all of which limit productivity and sustainability. Considering these challenges, the adoption of natural feed additives has emerged as a promising strategy to enhance animal performance, optimise nutrient utilisation, and mitigate environmental impacts, including the reduction of enteric methane emissions. This review underscores the significant potential of natural feed additives such as plant extracts, essential oils, probiotics, and mineral-based supplements such as fossil shell flour as sustainable alternatives to conventional growth promoters in ruminant production systems across the region. All available documented evidence on the topic from 2000 to 2024 was collated and synthesised through standardised methods of systematic review protocol—PRISMA. Out of 319 research papers downloaded, six were included and analysed directly or indirectly in this study. The results show that the addition of feed additives to ruminant diets in all the studies reviewed significantly (p < 0.05) improved growth parameters such as average daily growth (ADG), feed intake, and feed conversion ratio (FCR) compared to the control group. However, no significant (p > 0.05) effect was found on cold carcass weight (CCW), meat percentage, fat percentage, bone percentage, or intramuscular fat (IMF%) compared to the control. The available evidence indicates that these additives can provide tangible benefits, including improved growth performance, better feed efficiency, enhanced immune responses, and superior meat quality, while also supporting environmental sustainability by reducing nitrogen excretion and decreasing dependence on antimicrobial agents. Full article

(1) Background: The urate-lowering effects of three iridoid glycosides, which are paederosidic acid, paederosidic acid methyl ester, and paederoside, isolated from Paederia foetida and the protection they provide against hyperuricemia-induced kidney injury were investigated in a rat model. (2) Methods: A hyperuricemia (HUA) rat model was established in Sprague-Dawley (SD) rats through intraperitoneal potassium oxonate (PO) and intragastrical adenine for 2 weeks. Subsequently, rats in the pharmaceutical intervention groups received corresponding drug treatments at a concentration of 40 mg/kg/day, maintained consistently for 7 days. (3) Results: The results showed that three compounds reduced serum urate (SU), creatinine (CRE), and blood urea nitrogen (BUN) levels and that the urinary excretion levels of uric acid, urine urea nitrogen, and creatinine increased. Furthermore, the administration of three iridoid glycosides enhanced renal filtration capacity, as demonstrated by the elevated 24 h creatinine clearance rate (CCR) and 24 h uric acid clearance rate (CUA); improved the fraction excretion of uric acid (FEUA); and attenuated renal damage. Finally, three iridoid glycosides promoted uric acid excretion in HUA rats by downregulating URAT1 and GLUT9 and upregulating ABCG2, OAT1, and OAT3. Moreover, the molecular docking results further corroborated the finding that the three compounds can bind to multiple sites of the uric acid transporter via hydrogen, P-π, and hydrophobic bonds. (4) Conclusions: The three iridoid glycosides were found to lower SU levels by increasing uric acid excretion. They are promising natural products for the prevention of HUA and HUA-induced kidney injury. Full article

A reliable estimation of protein requirements in lactating dairy cows is necessary for formulating nutritionally adequate diets, improving feed efficiency, and minimizing nitrogen excretion. This study aimed to develop machine learning-based models to predict net protein requirements for maintenance (NPm) and lactation (NPl) using random forest regression (RFR) and support vector regression (SVR). A total of 1779 observations were assembled from 436 peer-reviewed publications and open-access databases. Predictor variables included farm-ready variables such as milk yield, dry matter intake, days in milk, body weight, and dietary crude protein content. NPm was estimated based on the National Academies of Sciences, Engineering, and Medicine (NASEM, 2021) equations, while NPl was derived from milk true protein yield. The model adequacy was evaluated using 10-fold cross-validation. The RFR model demonstrated higher predictive performance than SVR for both NPm (R² = 0.82, RMSEP = 22.38 g/d, CCC = 0.89) and NPl (R² = 0.82, RMSEP = 95.17 g/d, CCC = 0.89), reflecting its capacity to model the rule-based nature of the NASEM equations. These findings suggest that RFR may provide a valuable approach for estimating protein requirements with fewer input variables. Further research should focus on validating these models under field conditions and exploring hybrid modeling frameworks that integrate mechanistic and machine learning approaches. Full article

A key factor in calculating dairy cows’ nitrogen (N) excretion is knowing the amount of daily excreted urine. The present study aimed to investigate two methods to calculate the daily urine volume (UV) excreted using spot urine samples. Data were obtained from nine balance experiments involving 47 lactating and seven non-lactating German Holstein cows, with an average body weight (BW) of 620 ± 95 kg and an average age of 5.6 ± 1.4 years. Daily urinary creatinine (Cr) and UVs were known for all animals. The first method was developed by linearly regressing the daily excreted amount of Cr in urine against BW (p < 0.001; R² = 0.51; RSE: 2.8). The slope of the regression was used to calculate UV. The second method includes a non-linear regression of UV on Cr concentration in urine, allowing direct estimation of UV without knowledge of BW (p < 0.001; RSE: 8.13). Both estimation methods were compared to the standard method to determine UV from balance trials using Lin’s concordance correlation coefficient (CCC) and Bland–Altman plots. The first method had a CCC of 0.81, and the second method had a CCC of 0.85. Both methods can confidently be applied to calculate UV. Therefore, the second method is usable if BW is unavailable. Full article

The objective of this study was to evaluate the effects of various feed additives on odor emissions, gut health, and stress responses in laying hens fed low-protein diets. Four commercially available functional feed additives (Bacillus subtilis, protease, saponin, and thyme-based essential oil) were selected for this study. A total of 288 Hy-Line brown laying hens aged 49 weeks were randomly fed on one of six experiment diets: a 16% standard crude protein diet, a 12% low-crude-protein (LCP) diet, and LCP diets supplemented with Bacillus-based probiotic, protease, saponin, or thyme-based essential oils prepared for 8 weeks. Each treatment had eight replicates with six birds per replicate. Lowering crude protein levels affected the laying performance, nitrogen balance, odor production (i.e., ammonia), and nutrient digestibility but did not alter eggshell quality or fecal short-chain fatty acids. Dietary additives added into the LCP diet did not affect the laying performance, egg qualities, and nitrogen balance but increased crude ash digestibility compared with the LCP-diet-fed laying hens. Branched-chain fatty acids tended to be higher in all laying hens fed low-CP diets, irrespective of feed additives. Notably, low vs. standard protein diets tended to increase yolk corticosterone levels, which is an indicator of stress responses in chickens. This low-CP-mediated increase in yolk corticosterone was partially decreased by 20.8–48.6% on average, depending on the additives used. Our study suggests that low-protein diets could effectively lower nitrogen excretion and odor emissions. However, adding dietary additives into low-protein diets has minimal effects on low-CP-diet-fed laying hens, which needs further studies to clarify the role of low-crude-protein diets and dietary additives in modulating hindgut fermentation via shaping the gut microbiota and stress responses of laying hens. Full article

Chitosan and technical cashew nutshell liquid (CNSLt) have emerged as promising natural compounds due to their antimicrobial, immunomodulatory, and fermentation-modulating properties. This study aimed to evaluate the inclusion of chitosan and CNSLt as potential substitutes for the ionophore monensin on feed intake, ruminal fermentation, nitrogen balance, and microbial protein synthesis in steers. Five crossbred steers (Bos taurus), 18 months old with an average body weight of approximately 350 kg and fitted with permanent ruminal cannulas, were assigned to a 5 × 5 Latin square design. The experimental diets consisted of: (1) control (CON), (2) monensin (MON; 25 mg/kg of dry matter [DM]), (3) chitosan (CHI; ≥850 g/kg deacetylation degree, 375 mg/kg DM), (4) CNSLt (500 mg/kg DM), and (5) CNSLt + CHI (500 + 375 mg/kg DM). Supplementation with CHI or CNSLt + CHI reduced the intake of dry matter, crude protein, and neutral detergent fiber. Additionally, fecal excretion of whole corn kernels increased in these treatments. Ruminal fermentation parameters were affected, with the CNSLt + CHI treatment promoting higher molar proportions of propionate and acetate, along with reduced estimated methane emissions. However, purine derivatives, microbial protein synthesis, and nitrogen balance were not significantly affected by any of the treatments. These results suggest that CNSLt and CHI, particularly when combined, may serve as effective natural alternatives to monensin in high-grain diets for ruminants. Full article

Extreme weather events such as heavy rainfall significantly reduce surface salinity in coastal waters, presenting considerable challenges to the aquaculture of Japanese scallops (Mizuhopecten yessoensis) in shallow cage systems. This study investigated the effects of chronic low-salinity stress on the growth performance, antioxidant capacity, and gene expression profile of M. yessoensis using a 60-day salinity gradient experiment. S33 represents the control treatment with normal seawater salinity (33‰), while S30, S28, and S26 represent experimental groups with progressively lower salinities of 30‰, 28‰, and 26‰, respectively. A decline in salinity was accompanied by an increase in oxygen consumption. The S26 group exhibited a higher ammonia excretion rate (2.73 μg/g·h) than other groups, indicating intensified nitrogen metabolism. Growth was inhibited under low-salinity conditions. The S33 group exhibited greater weight gain (16.7%) and shell growth (8.4%) compared to the S26 group (11.6% and 6%), which also showed a substantially higher mortality rate (46%) compared to the control (13%). At 28‰, antioxidant enzyme activities (T-AOC, SOD, CAT, POD) were elevated, indicating a moderate level of stress. However, at the lowest salinity (26‰), these indicators decreased, reflecting the exhaustion of the antioxidant systems and indicating that the mollusks’ adaptive capacity had been exceeded, leading to a state of stress fatigue. NAD-MDH activity was elevated in the S26 group, reflecting enhanced aerobic metabolism under stress. Transcriptome analysis revealed 564 differentially expressed genes (DEGs) between the S33 and S26 groups. Functional enrichment analysis indicated that these DEGs were mainly associated with immune and stress response pathways, including NF-κB, TNF, apoptosis, and Toll/Imd signaling. These genes are involved in key metabolic processes, such as alanine, aspartate, and glutamate metabolism. Genes such as GADD45, ATF4, TRAF3, and XBP1 were upregulated, contributing to stress repair and antioxidant responses. Conversely, the expressions of CASP3, IKBKA, BIRC2/3, and LBP were downregulated, potentially mitigating apoptosis and inflammatory responses. These findings suggest that M. yessoensis adapts to chronic low-salinity stress through the activation of antioxidant systems, modulation of immune responses, and suppression of excessive apoptosis. This study provides new insights into the molecular mechanisms underlying salinity adaptation in bivalves and offers valuable references for scallop aquaculture and selective breeding programs. Full article

Environmental pollution remains a significant challenge in animal production. The “ideal protein” concept refers to an amino acid profile that precisely meets the animal’s nutritional requirements, optimizing nutrient utilization and minimizing waste excretion. This study applied untargeted metabolomics to explore metabolic changes induced by limiting AA. Two experimental diets were used in 47-day-old growing rabbits: Met+ (with a methionine level balanced to its optimal utilization) and Met− (with a methionine level that was clearly limiting). A total of 68 blood samples were taken for untargeted metabolomics analysis and 88 were taken for targeted plasmatic urea nitrogen analysis, collected at 08:00 (in ad libitum feeding animals) and 21:00 (after a feeding event in 10 h fasting animals). Our results revealed that both sampling time and diet (at each time point) exerted a significant modulatory influence on the metabolome. Interestingly, the difference between the metabolomes obtained with the different diets was less pronounced at 08:00, likely due to the caecotrophy effect, compared to 21:00, when higher intake and lower caecotrophy frequency were observed. This study identifies pseudourine, citric acid, pantothenic acid, and enterolactone sulfate as promising metabolites that could be targeted in order to refine the ideal protein concept, thus improving nutrient efficiency and reducing the environmental impact of animal production. Full article

Hyperuricemia (HUA) is a metabolic disorder characterized by excessive uric acid (UA) production and impaired excretion. Goji, as a representative medicinal food, holds significant research and development value, while probiotic fermentation technology is finding increasingly widespread applications in the functional food sector. This study developed a novel goji fermented with three probiotic strains (Lactoplantibacillus plantarum CGMCC8198, Lactococcus lactis LTJ28, and Lactocaseibacillus casei YR2-2) and investigated its anti-HUA effects. Optimal fermentation conditions (7.913 material–liquid ratio, 3.92% inoculation, 7.49 h at 37 °C with 1:1:2 strain ratio) yielded a beverage with enhanced flavor profiles (19 aroma compounds) and high viable counts. In HUA cell models, the 15% fermented goji juice significantly reduced UA levels by 56% (p < 0.01). In potassium oxonate-induced HUA mice, the beverage effectively lowered serum UA, xanthine oxidase activity, and renal function markers (blood urea nitrogen and creatinine, p < 0.0001) while improving hepatic parameters (alanine aminotransferase, aspartate Aminotransferase). The goji-fermented juice significantly reduced the expression of renal UA transporters GLUT9 and URAT1 (p < 0.0001) while improving gut microbiota composition, as evidenced by increased beneficial SCFAs (acetic acid, butyric acid, p < 0.0001) and elevated Lactobacillus abundance 2.14-fold. Our findings demonstrate that this triple-probiotic-fermented goji beverage represents an effective dietary strategy for HUA management by simultaneously inhibiting UA production, enhancing excretion, and restoring gut microbiota homeostasis, providing a scientific basis for developing probiotic-based functional foods against HUA. Full article

A meta-regression was conducted on studies published from 2018 to 2023 to explore the effects of nutrient intakes from alfalfa (ALF) and corn silage (CS) on milk yield (MY), energy-corrected milk yield (ECM), N efficiency (N_EFF), milk urea nitrogen (MUN), and manure nitrogen excretion (N_MANURE) in Holstein lactating cows. The analysis included 193 studies with 698 individual treatment means. Multiple models were developed for each response variable using a backward stepwise approach and cross-evaluated against the database. Nutrient intake from both CS and ALF influenced MY and ECM, with ALF generally having a positive effect. The N_EFF was also affected by nutrient intakes from both forages. Generally, greater protein intake reduced N_EFF, whereas greater MY was associated with improved N_EFF. An increase in the rumen-degradable protein intake (RDPI), especially from ALF, increased MUN. However, no significant effect of protein intake from CS on MUN was observed. Additionally, an increase in crude protein intake and RDPI, regardless of source (CS or ALF), led to an increase in g/d of N_MANURE. Our results indicate that nutrient intakes from ALF and CS have different effects on production, excretion, and nitrogen efficiency, supporting their use in targeted nutrient and waste management strategies. Full article

This study evaluated the effects of dietary lysine supplementation in low-protein diets on nutrient digestibility, nitrogen metabolism, growth performance, serum biomarkers, and pelt quality in female blue foxes (Alopex lagopus) during the fur-growing period. A total of 105 18-week-old female blue foxes were randomly assigned to seven groups (n = 15 per group). The control group received a standard-protein diet (28% dry matter, DM), while six experimental groups were fed low-protein diets (26% DM) supplemented with 0%, 0.2%, 0.4%, 0.6%, 0.8%, and 1.0% lysine, corresponding to total lysine levels of 0.75%, 0.95%, 1.15%, 1.35%, 1.55%, and 1.75% DM, respectively. Lysine supplementation at 1.35% and 1.55% DM significantly improved the digestibility of ether extract and amino acids, including aspartic acid, glycine, methionine, isoleucine, and tyrosine (p < 0.05). Nitrogen retention increased accordingly, indicating enhanced dietary utilization (p < 0.05). Daily weight gain, particularly from day 15 to day 30, was significantly higher in 1.15–1.55% lysine groups compared to low-lysine groups (p < 0.05), achieving growth performance comparable to the control (p > 0.05). Serum total protein and albumin concentration were significantly improved with increasing lysine levels in low-protein groups (p < 0.01), aligning with those of the control group (p > 0.05). Furthermore, high lysine supplementation significantly improved pelt quality, as evidenced by the increased underfur length and decreased guard hair/underfur in 1.35–1.75% DM (p < 0.05). These findings suggest that lysine supplementation in low-protein diets supports nutrient utilization, growth performance, and metabolic health status while reducing dietary protein content. The optimal dietary lysine range is 1.15% to 1.55% DM (corresponding to 0.4% to 0.8% in air-dry basis), with 1.35% DM (corresponding to 0.6% in air-dry basis) identified as the most suitable level for balancing growth, nitrogen excretion, and pelt quality in fur-growing female blue foxes. Full article

In recent years, much attention has been paid to environmental protection, not only by reducing emissions of harmful gases from industry, but also by reducing the excretion of biogenic compounds or ammonia emissions from agriculture, including animal production. The aim of this study was to determine the effects of complete diets with reduced inclusion levels of crude protein and limiting essential amino acids, fed to pigs in two- and three-phase feeding systems, and the feeding system on crude protein digestibility, nitrogen retention and utilization, fecal and urinary pH, fecal and urinary nitrogen and ammonia levels, and nitrogen excretion. Digestibility-balance trials were performed on 24 growing–finishing pigs housed in individual metabolism crates, in three groups, in two- and three-phase feeding systems. The pigs were fed the following diets: C-control diet; L-low-protein diet where the levels of crude protein and essential amino acids (lysine, methionine + cystine, threonine, and tryptophan) were reduced by 15% relative to diet C; L+AA-low-protein diet supplemented with crystalline lysine, methionine, threonine, and tryptophan to the standard levels (as in diet C). Diets L fed to pigs in two- and three-phase feeding systems significantly decreased crude protein digestibility and nitrogen retention, particularly in the three-phase system. The supplementation of diets L+AA with crystalline essential amino acids improved crude protein digestibility and nitrogen retention and utilization, especially in the two-phase system. Reduced concentrations of crude protein and essential amino acids in diets L contributed to a significant increase in feces and urine acidity in both two- and three-phase feeding systems. The supplementation of diets L+AA with essential amino acids resulted in a significant increase in urinary pH and a non-significant increase in fecal pH. This experimental factor had no effect on fecal ammonia concentration in group L+AA. The values of pH and total fecal nitrogen were somewhat higher in the two-phase system than in the three-phase system. Fecal ammonia concentration was similar in both systems. The three-phase feeding system contributed to a decrease in urinary pH and total urinary nitrogen. The analyzed feeding systems had no significant effect on urinary ammonia concentration. It was estimated that a reduction in crude protein (by 20–25 g/kg) and essential amino acid levels in pig diets, relative to the standard levels, reduced nitrogen excretion by 18.7% and 15.6% in two- and three-phase feeding systems, respectively. The supplementation of low-protein diets (L) with lysine, methionine, threonine, and tryptophan induced a further reduction in nitrogen excretion. A comparison of the effects of feeding systems (two-phase system vs. three-phase system) on crude protein digestibility and nitrogen retention and utilization revealed that better results were obtained in the two-phase feeding system. Full article

Objectives: This study investigated the effects and mechanisms of electrolyzed alkaline water (EAW), a type of drinking water, on hyperuricemia (HUA) in mice. Methods: A hyperuricemia model was established by intraperitoneal injection of potassium oxonate and free access to a high-purine diet. EAW was provided ad libitum for 21 days. Results: The results showed that EAW had little impact on the levels of blood urea nitrogen, alanine aminotransferase, aspartate aminotransferase, albumin, or xanthine oxidase in mice (p > 0.05). Interestingly, EAW ingestion induced significant reductions in uric acid and creatinine levels (p < 0.05), along with increased urinary uric acid excretion (p < 0.05) and less renal pathological changes in mice. Additionally, EAW upregulated GLUT9 gene expression (p > 0.05) and downregulated URAT1 protein expression. Conclusions: In conclusion, this study demonstrates that EAW promotes uric acid excretion by downregulating URAT1 and GLUT9 protein expression, resulting in a significant reduction in uric acid levels. Full article

This study investigated the effects of dietary carbohydrate levels (control 8.13%, HG1 12.03%, and HG2 14.15%) on growth performance and glutamate metabolism in Chinese perch (S. chuatsi) (initial weight: 39.12 ± 0.25 g) reared at 12–15 °C. Diets were isonitrogenous (49% protein). After 8 weeks, the HG1 group optimized weight gain rate (WGR), specific growth rate (SGR), and protein efficiency ratio (PER), while reducing feed conversion ratio (FCR). HG1 and HG2 groups reduced liver glutamate/glutamine levels while downregulating the expression of key ammonia-metabolizing genes (gs, gdh, and ampd), collectively suppressing glutamate-mediated ammonia excretion. HG1 and HG2 groups enhanced glycolysis (upregulated gk and pk) coupled with suppressed gluconeogenesis (decreased PEPCK and G6Pase activities) in the liver. Concurrent downregulation of proteolytic markers (mafbx and murf1) in the muscle indicated improved protein conservation efficiency in the HG1 and HG2 groups. The HG1 diet optimally enhances growth by promoting glycolysis, reducing ammonia excretion, and improving feed efficiency. The insights gained from this research will be used to refine the low-temperature culture feed for Chinese perch, aiming to decrease ammonia and nitrogen emissions, thereby advancing the practice of low-ammonia emission culture for this species. Full article

Italian pigs for slaughter weigh between 150 and 170 kg, and their breeding is strictly regulated by the Protected Designation of Origin. Intensive production raises environmental concerns, in particular, nitrogen (N) emissions. To address these issues, low-crude-protein diet strategies have been proposed. However, few experiments have tested the effects of very low crude protein levels on performance and nitrogen efficiency, above all, in heavy pigs. The aim of our study was to explore new feeding solutions, compared to traditional ones, in accordance with PDO regulations, from 50 kg live weight to slaughtering: (1) traditional diet based on soy and maize; (2) iso-protein diet protein that is pea-based; and (3) low-crude-protein (−24.5% vs. C and T1 diets) diet that is cereal-based. Our results show that the use of different protein sources and the very low crude protein levels did not influence the technical efficiency and quality parameters; instead, a highly significant difference (p < 0.01) was recorded in the nitrogen efficiency of the cereal-based diet both in terms of nitrogen excretion and efficiency, achieving −28% and +21%, respectively. These results open up very interesting scenarios regarding the future feeding of heavy pigs and the cropping systems on which this is based. Full article