Dietary curcumin supplementation enhanced growth performance, intestinal digestion, and absorption and amino acid transportation abilities in on‐growing grass carp ( Ctenopharyngodon idella )

Abstract

This study investigated the effect of curcumin on growth performance, intestinal digestion, and absorption and amino acid transportation in on‐growing grass carp (Ctenopharyngodon idella). Curcumin at six levels (control (0), 120, 240, 360, 480 and 600 mg/kg) was included in the fish diets for 60 days. Dietary curcumin supplementation increased weight gain, final body weight, body length, percentage weight gain, specific growth rate, feed intake, feed efficiency, intestinal somatic index, intestinal protein content, intestine weight, folds height, digestion enzyme and brush border enzyme activities of the on‐growing grass carp. Notably, based on the quadratic regression of percentage weight gain, the most appropriate curcumin supplementation level was estimated to be 312.27 mg/kg in the diet of on‐growing grass carp. Curcumin diversely enhanced the mRNA abundance of neutral and cationic amino acid transporters, neutral amino acid transporters, cationic amino acid transporter, anionic amino acid transporters and peptide transporter 1 in the different segments of the fish intestine. In addition, curcumin up‐regulated the target of rapamycin (TOR) signalling pathway molecules. Therefore, curcumin was beneficial for the growth performance of fish by improving intestinal growth and development, intestinal digestion, and absorption, and amino acid transportation abilities.