Dietary condensed tannins improved growth performance and antioxidant function but impaired intestinal morphology of Litopenaeus vannamei

Abstract Although effects of dietary condensed tannins (CT) on growth and health of fish have been evaluated, limited information is available on shrimp. This study investigated the effects of CT on growth, nutrient digestibility, antioxidant response and intestinal histomorphology of Litopenaeus vannamei. A 56-day feeding trial was conducted by randomly distributing 600 shrimp into 15 tanks with 40 shrimp per tank and fed five diets containing 0 (G0), 0.5 (G0.5), 1 (G1), 2 (G2) and 4 (G4) g/kg of grape seed CT respectively. Shrimp were fed to apparent satiation during the entire feeding trial and feces were collected daily for the last 14 days to determine nutrient digestibilities. Hepatopancreas and intestine samples were collected to analyze antioxidant-related genes expression and histomorphology. Results indicated that dietary CT linearly increased final body weight, weight gain rate and specific growth rate (0.05   0.05). As compared with G0, dietary CT increased superoxide dismutase (G0.5, G1 and G2), glutathion peroxidase (G1 and G2) and nuclear factor erythroid 2-related factor 2 (G0.5, G1, G2 and G4) mRNA levels (P