Effects of bioactive peptides derived from cottonseed meal solid-state fermentation on the growth, metabolism, and immunity of yellow-feathered broilers.

This study investigated the effects of bioactive peptides derived from solid-state fermentation of cottonseed meal on the growth performance, apparent dietary digestibility, serum biochemical parameters, protein metabolism, antioxidant activity, and immunity in yellow-feathered broilers. A total of two hundred forty 21-days-old male broilers were randomly divided into four groups with six replicates per group. The control group received a basal diet and three experimental groups were fed diets with 1%, 2%, and 3% cottonseed meal bioactive peptides (CSBP) replacing equivalent protein of cottonseed meal in basic diet. Dietary supplementation of 2% and 3% CSBP increased the average daily weight gain, crude protein digestibility, total serum protein, and immunoglobulin (Ig) G contents in serum (P < 0.05). The 3% CSBP increased albumin, total antioxidant capacity, spleen weight/bodyweight, interleukin-6, and IgM, while reducing the feed to gain ratio, total cholesterol, urea nitrogen, total superoxide dismutase, glutathione peroxidase, and malondialdehyde contents in serum (P < 0.05). The 2% CSBP diet increased PepT1 expression in duodenum, jejunum, and ileum (P < 0.05). The 1%, 2%, and 3% CSBP diets increased S6kinase-polypeptide-1 and inositol-3-hydroxylase expression in chest and leg muscles (P < 0.05). The CSBP addition in diets can improve growth performance, nutrient digestibility, protein metabolism, antioxidant, and immune capabilities of yellow-feathered broilers.