Search Results (62)

Background/Objectives: Urinary urea excretion is a marker of protein catabolism and follows circadian biological rhythms. Although small-scale studies have suggested a diurnal pattern, its population-level characterisation and determinants remain poorly defined. Methods: This cross-sectional study was conducted within the Ticino Epidemiological Stiffness Study (TEST-study), a population-based cross-sectional analysis of 1202 adults (≥18 years) recruited in the Italian-speaking region of Switzerland in 2017–2018. A final analytical sample of 859 participants provided 24 h urine collections divided into diurnal and nocturnal fractions, from which a day-to-night (Day/Night) urea excretion ratio was calculated as the primary outcome. Multivariable linear regression was used to identify independent determinants. Results: Across the cohort, a predominant nocturnal pattern of urinary urea excretion was observed, with a mean Day/Night ratio below 1. In younger women (<40 years), the ratio approached 1, indicating an attenuated Day/Night pattern, whereas older women (>65 years) displayed a significantly more pronounced nocturnal predominance. No comparable age-related trend was observed in men. In multivariable analysis, advancing age, greater nocturnal blood pressure dipping, and higher sodium excretion were independently associated with the Day/Night urea ratio. Conclusions: Urinary urea excretion, a surrogate marker of protein catabolism, exhibits a measurable Day/Night variation, associated with age, sex, and hemodynamic factors. These findings provide insights for chrononutritional strategies aimed at preserving muscle health across lifespan. Full article

The synchronization between nitrogen sources and carbohydrate fractions represents a critical factor for optimizing microbial protein synthesis and overall ruminant performance. This systematic review, conducted according to PRISMA 2020 guidelines, comprehensively evaluated the interactions between different nitrogen sources (true protein, urea, controlled-release urea, and bypass amino acids) and carbohydrate fractions (rapidly degrading soluble, slowly degrading soluble, fibrous, non-fibrous, and Van Soest fractions) in ruminant nutrition. A comprehensive search across PubMed, ScienceDirect, Web of Science, and Scopus databases identified 1855 records, of which 164 studies met the eligibility criteria for qualitative synthesis and 89 for quantitative meta-analysis. The review reveals that synchronization effectiveness varies significantly depending on the nitrogen source–carbohydrate combination, with controlled-release urea showing superior synchrony with slowly degrading carbohydrates, while conventional urea performs better with rapidly degrading sources. Meta-analytical results indicate that optimal nitrogen–carbohydrate synchronization can improve microbial protein synthesis by 18–34%, reduce urinary nitrogen excretion by 12–28%, and enhance feed efficiency by 8–15%. These findings provide evidence-based recommendations for precision nutrition strategies in ruminant production systems. Full article

Sesame meal possesses high crude protein content (40–50%), abundant methionine, and natural antioxidant components such as lignan compounds, making it a high-quality feed alternative to soybean meal in ruminant production. This study systematically evaluated the effects of completely replacing soybean meal with sesame meal in the diet on growth performance, serum biochemistry, antioxidant activity, rumen fermentation parameters, and microbial composition in finishing beef cattle. The trial employed a completely randomised design, selecting 18 Angus bulls with similar initial body weights (566.7 ± 38.1 kg). Animals were randomly assigned to the SBM group (n = 9) and SSM group (n = 9), with a 7-day pre-trial period followed by a 96-day main trial period. Results indicate that replacing soybean meal with sesame meal significantly enhances the antioxidant capacity of fattening beef cattle. Catalase (CAT) activity markedly increased (p < 0.05), while glutathione peroxidase activity showed an upward trend (0.05 < p < 0.1). This improvement was accompanied by a substantial shift in rumen microbial composition, highlighted by a marked enrichment of beneficial bacteria including p_Verrucomicrobiota, p_Spirochaetota, g_CAG_352, norank_f_Lachnospiraceae, and g_Rikenellaceae_RC9_gut_group, which collectively contributed to greater microbial complexity and stability. Regarding nitrogen metabolism, urinary nitrogen and serum urea nitrogen levels were significantly reduced in the sesame meal group (p < 0.05), indicating improved nitrogen utilization efficiency. Overall, completely replacing soybean meal with sesame meal in the diet of finishing beef cattle did not adversely affect growth and slaughter performance. It simultaneously significantly enhanced antioxidant capacity, reduced urinary nitrogen excretion, and lowered feed costs. These findings underscore the potential of sesame meal as a sustainable, nutritionally advantageous alternative for optimising beef cattle diets. Full article

Urea is one of the most widely used sources of non-protein nitrogen (NPN) in ruminant diets due to its low cost and high availability. However, its rapid solubilization in the rumen can result in abrupt ammonia release, leading to toxicity risks and low nitrogen utilization efficiency. In this context, slow-release technologies, particularly microencapsulation, have been developed to synchronize NPN release with fermentable carbohydrate availability, thereby enhancing microbial protein synthesis, improving animal performance, and reducing environmental impacts. This review compiles recent advances in urea microencapsulation, emphasizing different wall materials such as waxes, lipids, polysaccharides, and fatty acids, as well as drying techniques and formulation strategies. Slow-release urea (SRU) addition in small ruminants’ diet may increase nutrient intake and digestibility, improve N balance, and reduce urinary excretion losses. Regarding performance, positive responses are observed when nitrogen release is properly synchronized with energy availability, although the results may vary depending on the encapsulant type, forage-to-concentrate ratio, and ruminal passage rate. Additionally, effects on meat quality and environmental parameters indicate that this technology holds not only zootechnical but also socio-environmental potential. It is concluded that urea microencapsulation can represent a promising alternative to optimize NPN use efficiency in ruminant production systems, though greater methodological standardization, long-term evaluations, and comparative economic analyses are required to encourage its broader adoption. Full article

Background: Cardiovascular diseases are the leading cause of death globally, with hypertension and high sodium intake being major contributors. Accurate estimation of sodium intake is essential, but 24 h urine collection, the gold standard, is cumbersome and impractical for routine clinical use. Existing spot urine-based prediction formulae lack accuracy at the individual and population level. Objective: To develop and validate population-specific formulas for estimating 24 h urinary sodium excretion from spot urine samples using data from a representative Swiss adult population. Methods: Models with and without urea and potassium were developed incorporating age, sex, and anthropometry-based, population-specific, estimated urinary creatinine excretion values. Data quality was rigorously controlled, and model performance was compared to the INTERSALT, Kawasaki, and Tanaka formulae and to a nocturnal timed urine collection used to calculate hourly creatinine excretion. Results: Models based on first morning urine demonstrated improved accuracy (AUCs: Swiss anthropometric model 0.85 (95% CI: 0.80–0.90), Swiss anthropometric model with urea 0.86 (95% CI: 0.81–0.91)) and lower bias (−5.5 mmol/24 h for the Swiss anthropometric model and −2.86 mmol/24 h for the Swiss anthropometric model with urea) compared to existing equations. Performance was consistent across clinically relevant sodium intake thresholds and the models were therefore suitable for use in clinical settings. A timed nocturnal urine collection further improves accuracy. Conclusions: These new simple and reliable formulae provide a promising and practical tool for estimating sodium intake from first morning urine spot in adult European populations, and are potentially applicable in clinical settings. Full article

Hyperuricemia, characterized by elevated serum uric acid levels, is a major risk factor for gout and kidney disease. This study evaluated the antihyperuricemic effects of Cornus officinalis extract (COE) using urate transporter 1 (URAT1)-expressing oocytes and a hyperuricemia rat model. COE effectively inhibited uric acid absorption by modulating URAT1, with an IC₅₀ value of 3.24 µg/mL. In the hyperuricemia model, COE administration (100 and 200 mg/kg) significantly reduced serum uric acid levels and increased urinary uric acid excretion. The primary constituents of COE, morroniside (MO) and loganin (LO) exerted similar effects, with MO exhibiting potent inhibition of uric acid absorption even at low concentrations. Kidney tissue analysis revealed a reduction in blood urea nitrogen (BUN) levels, indicating improved renal function. Liver function parameters (ALT, AST, and LDH) remained unchanged, suggesting an absence of hepatotoxicity. Ultra-high-performance liquid chromatography with charged aerosol detection (UHPLC-CAD) analysis identified MO (17.8 mg/g), LO (9.8 mg/g), and cornin (1.4 mg/g) as the principal components of COE. These findings suggest that COE enhances uric acid excretion via URAT1 regulation and exerts renoprotective effects, highlighting its potential as an antihyperuricemic agent. Furthermore, MO and LO were identified as the primary active constituents, and COE appears to be a promising therapeutic candidate with a favorable safety profile. Full article

Background/Objectives: Monitoring of 24 h urine analysis is currently used to assess diet-related stone risk factors due in most cases to low hydration and high osmole intake accounting for urine supersaturation. The aim of our study is to test whether urine conductivity could be a relevant surrogate marker of urine osmolality and a useful tool for monitoring salt and protein diets in primary care centers. Methods: 113 patients with kidney stone history referred for a routine evaluation of fasting and 24 h urine samples were included. Biochemical analysis of urine was performed, including measured osmolality (mUosm) and conductivity. Results: Among our population, 45% of patients have a low diuresis (high-risk group of stone recurrence) below the target of 2 L/day, with lower daily mUOsm and conductivity outflow compared to the low-risk patient group > 2 L/day (718 versus 852 mosm/Day, p < 0.0001, and 13,730 versus 17,890 mS/cm/day, p < 0.0001, respectively). Conversely to urine sodium and urea concentration, daily sodium and protein intake estimated by natriuresis and urea excretion are significantly lower in the high-risk group (p = 0.01 and <0.0001, respectively). In 24 h urine samples, osmolality and conductivity were strongly associated with diuresis. Moreover, a strong association between urinary osmolality and urine conductivity enables an estimated osmolality (eUosm) according to the following equation: eUosm = −41.656 + 0.057 × conductivity (r² = 0.93; p < 0.001) with a 95% limit of agreement (LoA) ranging from −7.2% to +7.3%. An eUosm threshold value < 900 mOsm/day is independently associated with sodium and protein intake targets (odd ratio: 19.2 and 6.4-fold, respectively, p < 0.0001 and 0.01). Conclusions: 24 h urine measured conductivity appears to be a reliable, easy-to-use tool for the screening and monitoring of diet-related stone patients in primary care centers. Full article

Bone marrow-derived mononuclear cells (BMMCs) have shown beneficial effects on tissue repair, largely attributed to the paracrine action of bioactive mediators such as lysophosphatidic acid (LPA). This study aimed to evaluate the effects of BMMC treatment in a rat model of renal ischemia/reperfusion (I/R) injury, focusing on LPA-related molecular pathways. Male Wistar rats were divided into three groups: control; I/R, subjected to bilateral renal artery clamping for 30 min followed by 24 h of reperfusion; and I/R + BMMC, which received 1 × 10⁶ BMMCs per kidney directly into the renal capsule post-ischemia. During reperfusion, the rats were placed in metabolic cages for urine collection, renal function and protein expression. BMMC treatment did not reverse the I/R-induced increase in urine volume or decrease in glomerular filtration rate, serum potassium, or filtered sodium load. However, it prevented proteinuria, increased blood urea nitrogen, and enhanced urinary potassium excretion. Mechanistically, BMMC treatment prevented I/R-induced upregulation of LPAR1, downregulated LPAR2 and LPAR3, restored plasma LPA levels, and reduced renal autotaxin content. These results suggest that BMMCs modulate harmful LPA-related signaling and may contribute to renal protection through paracrine mechanisms in the setting of acute I/R injury. 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

Tactical athletes and military personnel engaged in intense exercise need to consume enough quality protein in their diet to maintain protein balance and promote recovery. Plant-based protein sources contain fewer essential amino acids (EAAs), while pork loin contains a higher concentration of EAAs and creatine than most other animal protein sources. This study aimed to determine whether the ingestion of plant-based or pork-based military-style meals ready-to-eat (MREs) affects recovery from and subsequent Army Combat Fitness Test (ACFT) performance. Methods: Twenty-three (n = 23) University Corps of Cadets members participated in a randomized, double-blind, placebo-controlled, and crossover-designed study. Diets were prepared by a dietitian, food scientist, and chef to have similar taste, appearance, texture, and macronutrient content. The chef also labeled the meals for double-blind administration. Participants refrained from intense exercise for 48 h before reporting to the lab in a fasted condition with a 24 h urine sample. Participants donated a blood sample, completed questionnaires and cognitive function tests, and consumed a pre-exercise meal. After four hours, participants performed the ACFT according to military standards. Participants were fed three MREs daily while returning to the lab in a fasted condition at 0600 with 24 h urine samples after 24, 48, and 72 h of recovery. On day 3, participants repeated the ACFT four hours after consuming an MRE for breakfast. Participants resumed normal training and returned to the lab after 2–3 weeks to repeat the experiment while consuming the alternate diet. Data were analyzed using general linear model statistics with repeated measures and percent changes from baseline with 95% confidence intervals. Results: Results revealed that 3 days were sufficient for participants to replicate ACFT performance. However, those consuming the pork-based diet experienced less muscle soreness, urinary urea excretion, cortisol, inflammation, and depression scores while experiencing a higher testosterone/cortisol ratio and appetite satisfaction. There was also evidence of more favorable changes in red and white blood cells. Conversely, blood lipid profiles were more favorably changed when following a plant-based diet. Conclusions: These findings suggest that protein quality and the availability of creatine in the diet can affect recovery from intense military-style exercise. Minimally, plant-based MREs should include 6–10 g/d of EAA and 2–3 g/d of creatine monohydrate to offset dietary deficiencies, particularly in military personnel following a vegetarian diet. Registered clinical trial #ISRCTN47322504. 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 evaluated the effects of supplementing rumen-protected methionine, threonine, isoleucine, and leucine to low-protein diets on lactating dairy cow performance. Sixty Holstein cows were assigned to one of four dietary treatments in a 9-week randomized complete block design: positive control (16% crude protein diet; 16% CP), negative control (12% CP), 12% CP plus the four essential amino acids (12% CP + EAA), and 14% CP supplemented with the four EAA (14% CP + EAA). The milk protein yield was significantly decreased in the 12% CP group compared to the 16% CP group but was restored to comparable levels with EAA supplementation of both the 12% and 14% CP diets. Dietary nitrogen intake and urinary nitrogen excretion both increased with higher dietary CP levels. Nitrogen utilization efficiency in milk was significantly improved by EAA supplementation, with the highest efficiency observed in the 12% CP + EAA treatment (39.0% vs. 33.3% in the 16% CP diet). Plasma urea levels increased with elevated dietary CP and EAA supplementation. Moreover, EAA supplementation significantly elevated venous methionine levels and showed a tendency to increase venous leucine levels. Additionally, compared to the negative control, EAA supplementation increased concentrations of glucagon and prolactin (p < 0.05). EAA supplementation of low-protein diets, particularly the 14% CP diet, improved the dietary protein efficiency of lactating cows without a concomitant decrease in milk protein yield. Full article

The societal pressure on intensive pastoral dairying demands the search for strategies to reduce the amount of N flowing through and excreted by dairy cows. One of the strategies that is being currently explored focuses on the animal as a solution, as there are differences in N metabolism between cows even within the same herd. This work was conducted to explore such an approach in A1PF herds in New Zealand and the possibility of identifying A1PF cows that are divergent for milk urea nitrogen (MUN) concentration through phenotyping as a potential viable strategy to reduce N leaching and emissions from temperate dairy systems. Three herd tests were conducted to select a population sample of 200 cows (exhibiting the lowest 100 and highest 100 MUN concentrations). Milk samples were collected from the 200 cows during mid and late lactation to test for milk solids content and MUN. From the 200 cows, urine for urinary N concentration (UN), blood for plasma urea N, total antioxidants (TAS), and glutathione peroxidase (GPx) were collected from the 20 extremes (the lowest 10 and highest 10 MUN concentrations). Milk urea N was greater in cows selected as high-MUN cows (16.2 vs. 14.32 ± 0.23 mg/dL) and greater during late lactation (16.9 vs. 13.0 ± 0.19 mg/dL). Milk solids and fat content were 38% and 20% greater in cows selected as low-MUN cows than in high-MUN cows during mid lactation (p < 0.001). Low-MUN cows had lower UN than high-MUN cows during mid lactation (0.64 vs. 0.88 ± 0.11%). The N concentration in the plasma (p = 0.01) and Tas (p = 0.06) were greater during late lactation. There was a positive relationship between the MUN concentration phenotype used for selection and the MUN concentration for the trial period and MUN concentration and UN concentration during mid and late lactation (p < 0.001). Our results suggest that A1PF cows within a commercial herd can be phenotyped and selected for low-MUN, which may be potentially a viable strategy to reduce N losses to the environment and create healthier systems. Following genetic tracking, those cows can be bred to further promote low-MUN A1PF herds. Full article

This study tested the ISL against renal damage induced by a high-fat diet (HFD) and explored its underlying mechanisms. Adult male rats were assigned to four groups: (1) control on a standard diet (STD), (2) ISL on STD (30 mg/kg), (3) HFD, and (4) HFD + ISL (30 mg/kg). After 12 weeks of dietary intervention, ISL treatment led to significant reductions in body weight gain, visceral fat, and glucose and insulin levels in HFD-fed rats. Notably, ISL decreased serum urea and creatinine, increased serum albumin, and improved urinary profiles by lowering the urinary albumin and the albumin/creatinine ratio. Histological analyses revealed that ISL enhanced the glomerular structure and mitigated tubular damage, as evidenced by reduced urinary excretion of the kidney injury markers NGAL and KIM-1. Additionally, ISL significantly lowered cholesterol, triglycerides, and free fatty acids in both the control and HFD groups while also decreasing oxidized low-density lipoproteins (ox-LDLs) and malondialdehyde (MDA). Importantly, ISL enhanced renal antioxidant levels, increasing glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT). Moreover, ISL downregulated mRNA levels of MD-2, Toll-like receptor-4 (TLR-4), and NF-κB, leading to reduced NF-κB p65 levels in renal tissues. In conclusion, ISL offers substantial protection against HFD-induced renal toxicity through mechanisms that attenuate metabolic stress, enhance antioxidant defenses, and inhibit the MD-2/TLR4/NF-κB inflammatory pathway. Full article

This study investigated the effects of replacing maize silage (MZS) with high-sugar sorghum silage (HSS) or forage sorghum silage (FSS) without additional grain supplement in the diets of dairy cows on nutrient digestibility, milk composition, nitrogen (N) use, and rumen fermentation. Twenty-four Chinese Holstein cows (545 ± 42.8 kg; 21.41 ± 0.62 kg milk yield; 150 ± 5.6 days in milk) were randomly assigned to three dietary treatments (n = 8 cows/treatment). The cows were fed ad libitum total mixed rations containing (dry matter basis) either 40% MZS (MZS-based diet), 40% HSS (HSS-based diet), or 40% FSS (FSS-based diet). The study lasted for 42 days, with 14 days devoted to adaptation, 21 days to daily feed intake and milk production, and 7 days to the sampling of feed, refusals, feces, urine, and rumen fluid. Milk production was measured twice daily, and digestibility was estimated using the method of acid-insoluble ash. The data were analyzed using a one-way ANOVA in SPSS 22.0 according to a completely randomized design. Dietary treatments were used as fixed effects and cows as random effects. The results indicate that MZS and HSS had greater crude protein but less neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), and a lower pH than FSS (p ≤ 0.04). High starch contents in MZS and water-soluble carbohydrate (WSC) contents in HSS were observed (p < 0.01). While the highest starch intake was observed for the MZS-based diet, the highest WSC intake was noted for the HSS-based diet, and the highest NDF, ADF, ADL intake was observed for the FSS-based diet (p ≤ 0.05). The diets, including MZS and HSS, had greater digestibility than that of FSS (p ≤ 0.03). Feeding MZS- and HSS-based diets increased the yield, fat, and protein content of the milk, as well as feed conversion efficiency (p ≤ 0.03). However, feeding the MZS- and HSS-based diets decreased the contents of milk urea N, urinary urea N, and urinary N excretion more than the FSS-based diet (p ≤ 0.05). The N use efficiency tended to increase relative to diets containing MZS and HSS compared with FSS (p = 0.06 and p = 0.09). Ruminal ammonia-N and pH were lower, but total volatile fatty acids, acetate, and propionate were higher in cows fed the HSS- and MZS-based diets compared to those fed the FSS-based diet (p ≤ 0.03). It appears as though replacing MZS with HSS in the diet of cows without additional grain supplements has no negative influence on feed intake, milk yield, N utilization, or ruminal fermentation. Full article