Effects of enzymatic hydrolysis chicken by‐product in high plant‐based protein diet on growth performance, digestive capacity, antioxidant capacity and non‐specific immunity of juvenile turbot (Scophthalmus maximus L.). (23rd June 2021) - Zhuang, Yanwen
Abstract: A 60‐day feeding trial was conducted to investigate the effect of enzymatic hydrolysis chicken by‐product (EHC) supplementation in high plant protein diets on growth performance, digestive capacity, antioxidant capacity and non‐specific immunity of juvenile turbot ( Scophthalmus maximus L.). The diet with 620 g/kg fish meal (FM) was used as the positive control group (FM group), while the diet with 372 g/kg FM and 256 g/kg degossypolled cottonseed protein were used as the negative control group (0 g/kg EHC group). Based on the negative control diet, grade levels of EHC (10, 20, 30 and 40 g/kg) were added, respectively. Results showed that fish fed with a high plant protein diet showed significantly lower growth performance, digestive capacity, antioxidant capacity and non‐specific immunity than those of the positive control. The supplementation of 20 g/kg EHC significantly increased growth performance of fish as compared to the negative control. Furthermore, the digestive capacity of turbot fed the diet with 20 g/kg EHC was significantly improved by increasing activities of trypsin, pepsin and lipase and the expression of peptide transporter 1 ( pept1 ). The antioxidant capacity and non‐specific immunity of fish fed the diet with 20, 30 and 40 g/kg EHC were significantly improved by increasing activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), total antioxidant capacity (T‐AOC), lysozyme (LZM) and acid phosphatase (ACP) in serum, decreasing the expression of interleukin‐1β ( il‐1β ) and tumour necrosis factor‐α ( tnf‐α ) and increasing the expression of transforming growth factor‐β ( tgf‐β ). In conclusion, the adverse effect of high plant protein diet on growth performance of turbot could be improved with the supplementation of 20 g/kg EHC, which could be due to the positive effect of EHC on digestive capacity, antioxidant capacity and non‐specific immunity of juvenile turbot.