Shengnan Sun

Optimizing the dietary nitrogen-to-sulfur (N:S) ratio is crucial for enhancing ruminal microbial fermentation and nutrient digestibility. This study investigated the effects of different dietary N:S ratios on ruminal antioxidant indices, digestive enzyme activities, immune parameters, volatile fatty acid (VFA) profiles, microbial communities, and metabolomic profiles in plateau-type Tibetan sheep. Ninety 2-month-old male Tibetan sheep (initial body weight, 15.55 ± 0.20 kg) were randomly assigned to three dietary treatments formulated with N:S ratios of 9.5:1 (HP-H), 8.5:1 (HP-M), and 7.5:1 (HP-L). Sheep fed the HP-H diet exhibited improved ruminal antioxidant indices compared with the other treatments, with CAT and T-AOC activities being higher than those of both the HP-M and HP-L groups, while SOD and GSH-Px activities were significantly higher only compared with those in the HP-L (p < 0.05). Furthermore, ruminal cellulase activity, as well as propionate and butyrate levels, were significantly higher in the HP-H group (p < 0.05). Microbiome analysis revealed that the HP-H diet enriched the relative abundances of Candidatus Saccharimonas, the Rikenellaceae RC9 gut group, and uncultured rumen bacteria. Correspondingly, untargeted metabolomics identified higher signal intensities of 3-hydroxyphenylacetic acid, nervonic acid, arachidonic acid (peroxide-free), and calciferol in the ruminal fluid of the HP-H group relative to the other treatments. In conclusion, when the nitrogen-to-sulfur ratio was 9.5:1, ruminal antioxidant enzyme activities were increased, and the concentrations of propionic acid and butyric acid were increased. The differential microorganisms and metabolites were mainly associated with lipid metabolism, as well as cofactor and vitamin metabolism.

Introduction: Resveratrol (RES), a natural plant polyphenolic compound, can be used as a dietary supplement and has shown good application after addition to monogastric animal diets, but fewer studies have been conducted in ruminants, especially in Tibetan sheep where no deeper studies have been made. In this study, we used 16S rRNA and metabolomics systems to investigate the effects of different doses of resveratrol added to the diets of Tibetan sheep on the microbial community structure and metabolomics of their rumen. Results: The results showed a significant ( p < 0.05) increase in rumen papilla length in the H-RES group, along with elevated acetate and butyrate concentrations. Microbial analysis revealed significantly higher ( p < 0.05) relative abundance of Firmicutes in the H-RES group, including the genera Prevotella and Ruminococcus . Metabolic pathway enrichment analysis revealed significant ( p < 0.05) enrichment of amino acid metabolism-related pathways. In addition, specific microbial genera, Lactobacillus spp. and Ruminococcus spp. showed significant correlations with metabolites such as pantothenic acid and isoleucine, indicating differential regulatory effects. Conclusion: In summary, daily supplementation with 1.5 g of resveratrol (H-RES) improved rumen morphology and fermentation processes in Tibetan sheep. These improvements were closely related to changes in microbial community structure and metabolite interactions. The study of rumen microbial community structure and metabolite changes provides new ideas for regulating the rumen environment of Tibetan sheep.

Cellular senescence is a pivotal driver of aging and age-related diseases. This study aims to systematically investigate the anti-senescence effects and molecular mechanisms of a multi-component botanical complex (SBT) using both a D-galactose-induced senescence model in H9c2 cardiomyocytes and an H2O2-induced accelerated aging model in zebrafish. The SBT complex comprises Solms-laubachia eurycarpa, Bergenia purpurascens, Laccifer lacca, and Glycyrrhiza uralensis. Results demonstrated that SBT treatment significantly enhanced cell viability (increased from 52% to 85%) and reduced senescence-associated β-galactosidase (SA-β-gal) activity (from 41.2% to 20%). At the molecular level, SBT exerted bidirectional regulation of the P21/P53/SIRT1 axis, coordinately downregulating the pro-senescence proteins P53 and P21 while upregulating the longevity-associated deacetylase SIRT1. It also modulated the balance of apoptosis-related genes by suppressing Bax and enhancing Bcl-2 expression. In the zebrafish model, SBT significantly strengthened the antioxidant defense system, as indicated by increased activities of superoxide dismutase (SOD) and catalase (CAT), elevated glutathione (GSH) levels, and reduced malondialdehyde (MDA) content. These findings confirm that SBT exerts potent anti-senescence effects through bidirectional regulation of the P21/P53/SIRT1 signaling axis, enhanced antioxidant capacity, and inhibition of apoptosis, thereby providing a mechanistic foundation for the development of natural product-based interventions against aging and related diseases.

Background: Clinical data on the relationship between triglycerides (TG)/HDL ratio and insulin resistance (IR) suggest that TG/HDL ratio may be a risk factor for IR. However, there is evidence that different races have different risk of developing IR. The relationship on TG/HDL ratio and IR in various populations needs to be improved. Therefore, we investigated whether TG/HDL ratio was linked to IR in different groups in the United States after controlling for other covariates. Methods: The current research was conducted in a cross-sectional manner. From 2009 to 2018, the National Health and Nutrition Examination Survey (NHANES) had a total of 49,696 participants, all of whom were Americans. The target-independent variable was TG/HDL ratio measured at baseline, and the dependent variable was IR. Additionally, the BMI, waist circumference, education, race, smoking, alcohol use, alanine transaminase, aspartate transaminase, and other covariates were also included in this analysis. Results: The average age of the 10,132 participants was 48.6 ± 18.4 years, and approximately 4936 (48.7%) were males. After correcting for confounders, fully adjusted logistic regression revealed that TG/HDL ratio was correlated with IR (odds ratio = 1.51, 95% CI 1.42–1.59). A nonlinear interaction between TG/HDL ratio and IR was discovered, with a point of 1.06. The impact sizes and CIs on the left and right sides of the inflection point were 6.28 (4.66–8.45) and 1.69 (1.45–1.97), respectively. According to subgroup analysis, the correlation was strong in females, alcohol users, and diabetes patients. Meanwhile, the inverse pattern was observed in the aged, obese, high-income, and smoking populations. Conclusion: In the American population, the TG/HDL ratio is positively associated with IR in a nonlinear interaction pattern.