Dietary pyridoxine effect on growth performance, physiological metabolic parameters, intestinal enzymatic activities and antioxidant status of juvenile yellow catfish (Pelteobagrus fulvidraco)

Abstract

The experimental trial was conducted to assess the effects of dietary pyridoxine on growth performance, physiological metabolics, intestinal enzymatic activities and antioxidant properties of Pelteobagrus fulvidraco. Six isonitrogenous and isolipidic diets (420 g/kg protein and 70 g/kg lipid) were formulated to contain 3.69 (control), 5.45, 7.31,11.17, 19.43 and 33.94 mg/kg pyridoxine. Four groups of 30 fish (3.85 ± 0.01 g) per tank (300-L cylindrical fiberglass tanks) for each diet were fed to apparent satiation twice daily for 63 days. Blood, intestine and hepatopancreas samples were obtained for metabolic, enzymatic activities and antioxidant properties analyses. The results showed that significantly higher weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER), protein retention efficiency (PRE), whole-body crude protein, intestinal protease, alkaline phosphatase, Na+/K+-ATPase, γ-glutamyl transpeptidase and significantly lower feed conversion ratio were observed in fish fed diet with 7.31 mg/kg compared to those in control group (P < 0.05). There was a significant increase of intestinal villus length, villus width and muscular thickness in fish fed 5.45 or 7.31 mg/kg pyridoxine diets compared with those in control group (P < 0.05). The fish fed with 7.31 or 11.17 mg/kg pyridoxine diets had significantly higher intestosomatic index, relative intestinal length, serum total protein, triglyceride, cholesterol, hepatic glutathione peroxidase, superoxide dismutase (SOD), aspartate aminotransferase, alanine aminotransferase and lower viscerasomatic index, serum glucose, hepatic malondialdehyde compared to those in control group (P < 0.05). Based on WG, FCR, PER, crude protein, protease and SOD activities, the optimal dietary pyridoxine requirement of yellow catfish was estimated to be 6.70 −7.42 mg/kg using broken-line regression analysis.