Selective breeding has substantially improved productive and reproductive traits in pigs. Yet, these traits are biologically interconnected, and selection for one often affects others in unintended wa Show more
Selective breeding has substantially improved productive and reproductive traits in pigs. Yet, these traits are biologically interconnected, and selection for one often affects others in unintended ways. While genome-wide association studies (GWAS) have uncovered many loci linked to these traits, they provide limited insight into causal mechanisms. Mendelian randomization (MR) provides a robust framework for inferring causality and identifying shared genetic determinants. Here, we integrated MR, colocalization, and functional genomics to investigate the biological links between growth, carcass composition, and reproduction in pigs. Using average daily gain (ADG) as the exposure, MR revealed potentially significant causal effects (Pā<ā0.05) of ADG on carcass composition traits, including backfat thickness (BFT: Our findings suggest a shared genetic architecture and provide potential evidence of a causal influence of ADG on carcass composition and reproductive traits in pigs. This integrative framework supports the development of multi-trait breeding strategies that enhance productivity while managing inherent trade-offs in regulating complex traits. Show less
Sulfur metabolites of methionine (Met) and vitamin E (VE) have antioxidant potential and can maintain liver health in chickens. This study explored the underlying mechanisms of Met sources, the ratio Show more
Sulfur metabolites of methionine (Met) and vitamin E (VE) have antioxidant potential and can maintain liver health in chickens. This study explored the underlying mechanisms of Met sources, the ratio of total sulfur amino acids to lysine (TSAA: Lys), and VE levels on production performances, antioxidant potential, and hepatic oxidation in aged laying hens. Eight hundred and sixty-four, Hy-Line Brown laying hens (70-week age) were divided into 12 treatment groups, each having 6 repeats and 12 birds/each repeat. The dietary treatments consisted of DL-Met (DL-Met), DL-2-hydroxy-4-(methylthio)-butanoic acid (OH-Met), 3 ratios of TSAA: Lys (0.90, 0.95, and 1.00), and 2 levels of VE (20 and 40 g/ton). Albumen height and Haugh unit significantly increased at a lower level of VE (P < 0.05). Triglycerides (TG), total cholesterol (TC), low-density lipoprotein (LDL), and very low-density lipoprotein (VLDL) in serum and superoxide dismutase (SOD) and catalase activities (CAT) in the liver significantly reduced at 0.95 TSAA: Lys ratio (P < 0.05). Fatty acid synthase (FAS), lipoprotein lipase (LPL), nuclear factor erythroid 2-related factor 2 (Nrf2), and carnitine palmitoyltransferase-1 alpha (CPT-1Ī±) also upregulated at this TSAA: Lys ratio (P < 0.05). Compared with the DL-Met group, the OH-Met group had lower Dipeptidyl Peptidase 4 (DPP4) and higher TC, LDL, and VLDL concentrations (P < 0.05).The expression of FAS,CPT-1Ī±), glutathione (GSH), glutathione disulfide (GSSG), glutathione synthetase (GSS), and Nrf2 were significantly higher in OH-Met compared with the DL-Met group (P < 0.05). OH-Met at 0.95 and DL-Met at 0.90 TSAA: Lys ratio showed higher CAT and lower aspartate aminotransferase (AST) activities. Moreover, OH-Met at 0.90 and DL-Met at 0.95 of the TSAA: Lys ratio had a significant reduction of malondialdehyde (MDA) (P < 0.05). Overall, these results suggest that OH-Met source with a lower level of VE positively influenced production performance and improved liver health in aged laying hens through improved lipid metabolism and hepatic antioxidant function. Show less