Effects of dietary histidine on antioxidant capacity in juvenile Jian carp (Cyprinus carpio var. Jian)

In the present study, we tested the hypothesis that dietary histidine could improve antioxidant capacity of juvenile Jian carp (Cyprinus carpio var. Jian). A total of 1,200 juvenile Jian carp were fed graded levels of histidine at 2.3 (unsupplemented control), 4.4, 6.3, 8.6, 10.8 and 12.7 g/kg diet for 60 days. Results showed that the content of malondialdehyde (MDA) and protein carbonyl (PC) in serum and all tissues apparently decreased with increasing histidine levels up to an optimal level and increased thereafter. Anti-superoxide anion (ASA) capacity, glutathione peroxidase (GPX) activities and glutathione (GSH) content in serum and all tissues, anti-hydroxyl radical (a-HR) capacity, catalase (CAT) and glutathione-S-transferase (GST) activities in serum, muscle and intestine, superoxide dismutase (SOD) activities in serum and intestine, as well as glutathione reductase (GR) activity in serum, muscle and hepatopancreas were improved by dietary histidine. Fish fed diet with 8.6 g/kg histidine had lower serum glutamate-pyruvate transaminase (GPT) activity than that fed with control diet, whereas pattern of glutamate–oxaloacetate transaminase (GOT) activity was opposite. The present results suggested that histidine could improve antioxidant capacity and inhibit lipid peroxidation and protein oxidation of juvenile Jian carp.