The effect of cottonseed meal replacing soybean meal under processing techniques on the intestinal microbiota of grass carp

This study examined the effects of dietary protein source and processing on the intestinal microbiota of grass carp (Ctenopharyngodon idella). Juvenile fish were fed three different diets: a soybean meal (SBM)-based diet, an unprocessed cottonseed meal (CM)-based diet, and a hydrolyzed cottonseed meal (HCM)-based diet. The HCM was obtained by enzymatic hydrolysis of CM to improve its nutritional quality and reduce anti-nutritional factors. After the feeding trial, intestinal samples were collected and subjected to 16S rRNA gene sequencing to evaluate microbial composition and diversity. The study aims to elucidate how the replacement of SBM with CM and its hydrolyzed form affects gut microbial communities, with implications for sustainable aquafeed development.