title: Dietary taurine can improve the hypoxia-tolerance but not the growth performance in juvenile grass carp Ctenopharyngodon idellus.
abstract: This study was conducted to evaluate the effects of dietary taurine, as a feed additive, on the hypoxia-tolerance and growth performance of the juvenile grass carp Ctenopharyngodon idellus, one of the most important and intensively cultured freshwater fish, with the largest production in China. Graded levels of taurine (0, 0.5, 1, 1.5, 2 and 2.5 g kg(-1) dry diet) were fed to grass carp juveniles (mean weight: 5.26 ± 0.03 g) for 8 weeks. The survival time during acute hypoxia increased as dietary levels of taurine increased, with the highest dose of taurine resulting in the best acute hypoxia-tolerance. The erythrocyte osmotic fragility in grass carp was significantly improved when dietary taurine level was at least 1.5 g kg(-1) diet and can be improved much more when dietary taurine level was up to 2.5 g kg(-1) diet. A significant correlation between hemolysis rate of the erythrocyte osmotic fragility test and the survival time of acute hypoxia (r = -0.873, P = 0.023 < 0.05) strongly suggested that the biomembrane stabilization function of taurine may contribute to its role of enhancing acute hypoxia-tolerance in grass carp. Dietary taurine cannot improve growth performance of grass carp, but it can increase the value of mesenteric fat index, indicating that dietary taurine influences the lipid metabolism. This study provides valuable information to improve hypoxia-tolerance of grass carp.
authors.affiliation: Guangdong Provincial Key Laboratory for Aquatic Economic Animals, Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China.
authors.forename: Huijun
authors.initials: H
authors.lastname: Yang
authors.forename: Lixia
authors.initials: L
authors.lastname: Tian
authors.forename: Junwa
authors.initials: J
authors.lastname: Huang
authors.forename: Guiying
authors.initials: G
authors.lastname: Liang
authors.forename: Yongjian
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects*; D000704:Analysis of Variance; D000818:Animals; D002347:Carps / Q000254:growth & development* / Q000378:metabolism; D019587:Dietary Supplements; D000860:Hypoxia / Q000378:metabolism*; D050356:Lipid Metabolism / Q000187:drug effects; D008566:Membranes / Q000187:drug effects; D009996:Osmotic Fragility / Q000187:drug effects; D013654:Taurine / Q000494:pharmacology*
chemical_list: D013654:Taurine