title: Effects of dietary riboflavin levels on antioxidant defense of the juvenile grouper Epinephelus coioides.
abstract: This study was conducted to evaluate the effects of dietary riboflavin on antioxidant defense in the juvenile grouper Epinephelus coioides. Graded levels of riboflavin (0.9, 1.6, 4.4, 6.7, 12.9 and 19.4 mg kg(-1) dry diet) were fed to grouper juveniles (mean weight: 14.90 +/- 0.46 g) for 12 weeks. Higher levels of liver thiobarbituric acid reactive substances (TBARS) content were observed in grouper fed low doses (0.9 and 1.6 mg kg(-1) diet) of riboflavin. Both liver glutathione reductase (GR) activity and its activation coefficient (GR-AC) poorly responded to riboflavin deficiency. In addition, other indices of the glutathione-dependent defense system, including the activities of glutathione peroxidase (GSH-PX) and glutathione-S-transferase (GST), and the content of glutathione (GSH), were also non-significantly affected by dietary riboflavin levels. However, the activities of liver superoxide dismutase (SOD) and catalase (CAT) were significantly lower in fish fed 0.9 mg kg(-1) diet, with a positive correlation between the different groups. In conclusion, the present study indicated that the juvenile grouper fed the riboflavin-unsupplemented diet was susceptible to lipid peroxidation (LPO), with lower SOD and CAT activities in the liver. However, the glutathione-dependent defense system of grouper was not affected by dietary riboflavin levels.
authors.affiliation: Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-sen University, 135 Xingang West Street, Haizhu District, Guangzhou, 510275, Guangdong Province, People's Republic of China.
authors.forename: Junwa
authors.initials: J
authors.lastname: Huang
authors.forename: Lixia
authors.initials: L
authors.lastname: Tian
authors.forename: Xiangyun
authors.initials: X
authors.lastname: Wu
authors.forename: Huijun
authors.initials: H
authors.lastname: Yang
authors.forename: Yongjian
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D004032:Diet / Q000662:veterinary*; D019587:Dietary Supplements; D004798:Enzymes / Q000378:metabolism; D015227:Lipid Peroxidation; D008099:Liver / Q000737:chemistry / Q000201:enzymology*; D010473:Perciformes / Q000276:immunology*; D012256:Riboflavin / Q000008:administration & dosage*; D012257:Riboflavin Deficiency / Q000201:enzymology; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis
chemical_list: D000975:Antioxidants; D004798:Enzymes; D017392:Thiobarbituric Acid Reactive Substances; D012256:Riboflavin