AUTHOR=Qiu Jianqiang , Huang Wen , Cao Junming , Zhao Hongxia , Chen Bing , Jiun-Yan Loh , Peng Kai 

TITLE=Dietary hydrolyzable tannins reduce growth performance and induce histological damage of Chinese seabass (Lateolabrax maculatus)

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 10 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2023.1183438

DOI=10.3389/fmars.2023.1183438

ISSN=2296-7745

ABSTRACT=Chinese seabass (Lateolabrax maculatus) is a popular carnivorous fish with delicious taste. Although the feed value of condensed tannins has been well documented for L. maculatus, information about the effects of hydrolysable tannins (HT) on growth and health of L. maculatus is limited. This study was conducted to assess the effects of dietary HT on growth performance, body composition, intestinal digestive enzyme activities, serum metabolites, antioxidant and immune response, and intestine and liver morphology of L. maculatus. A total of 640 fish were randomly divided into 4 groups with 4 replicates per group and 40 fish per replicates. Four diets were prepared to contain 0 (G0), 1 (G1), 2 (G2) and 4 (G4) g/kg of HT. Fish were fed to apparent satiation twice a day during the 56-d feeding trial. Results showed that the final body weight, weight gain rate, specific growth rate and feed intake were linearly decreased (P < 0.001) as dietary HT increasing. All fish had similar (P > 0.05) whole body compositions. Fish fed G2 and G4 had lower (P < 0.05) intestinal trypsin and lipase activities than those fed G0 and G1, whereas G4 had higher (P < 0.05) aspartate aminotransferase and alanine aminotransferase activities than G0. Serum total antioxidant capacity and lysozyme were linearly decreased (P < 0.01) but the malondialdehyde concentration was linearly increased (P < 0.01) as dietary HT increasing. Intestinal villi in G2 and G4 showed increased deformation, and the vacuolation of liver cells began to appear in G1 and were aggravated as dietary HT increasing. This study showed that use of HT should be cautious due to their growth-inhibiting effect and the dietary HT level for L. maculatus is recommended to be less than 1 g/kg.