Dietary melatonin improves sperm motility and serum glutathione peroxidase activity: an exploratory multi-omics study in roosters.

This study investigated the effects of dietary melatonin supplementation on sperm motility and related physiological responses in Longyou Partridge Chicken roosters. A total of 107 roosters were assigned to a control group fed a basal diet or two treatment groups receiving diets supplemented with 20 or 40 mg/kg melatonin for 30 days. Sperm motility, serum antioxidant, immune, and hormone indicators, gut microbiota composition, and seminal metabolomic profiles were systematically evaluated. The results demonstrated that dietary melatonin supplementation significantly increased the total motile sperm ratio (TM), while serum glutathione peroxidase (GSH-Px) activity was significantly higher in the 40 mg/kg group. High-throughput 16S rRNA sequencing revealed exploratory treatment-associated taxonomic patterns, although no significant differences were detected in overall microbial diversity or community structure. Exploratory seminal metabolomic analysis identified 27 candidate metabolites, although none remained significant after FDR correction. Collectively, dietary melatonin supplementation improved total motile sperm ratio and serum GSH-Px activity at 40 mg/kg, whereas 16S and seminal metabolomic analyses showed exploratory trends. These findings provide preliminary evidence supporting dietary melatonin as a nutritional strategy to improve sperm motility in roosters.