Dietary histidine requirement for fingerlings of Channa punctatus (Bloch)

Abstract

To estimate the requirement of fingerling Channa punctatus (6.34 ± 0.08 g) for dietary histidine, the present study was conducted by feeding six isoproteic (450 g kg−1 CP) and isoenergetic (14.73 kJ g−1 DE) diets with six histidine levels (2.5, 5, 7.5, 10, 12.5 and 15 g kg−1 diet). The trial diets were fed for 12 weeks in a triplicate group of fish at 08:00, 12:30, and 17:30 h to apparent satiation. Absolute weight gain (AWG; 49.1 g fish−1), daily growth index (DGI, 2.34%), feed conversion ratio (FCR, 1.42), protein retention efficiency (PRE; 28.12), and histidine retention efficiency (HRE; 29.69%) improved significantly with increasing histidine from 2.5 to 12.5 g kg−1 diet. Dietary histidine concentrations considerably affected carcass protein, lipid, and moisture contents. Increment in hematocrit (Hct), hemoglobin (Hb), and red blood cell counts (RBCs) were noted with increasing histidine up to 12.5 g kg−1 after that decreased. In contrast, erythrocyte sedimentation rate (ESR) and erythrocyte osmotic fragility (EOF) showed a reverse pattern. Total Serum protein, superoxide dismutase (SOD), and catalase (CAT) activities responded positively up to 12.5 g kg−1 dietary histidine, whereas malondialdehyde (MDA) aspartate aminotransferase (AST) and alanine aminotransferase (ALT) significantly declined up to 12.5 g kg−1 of dietary histidine. Second-order regression of AWG, FCR, PRE, and HRE against different histidine concentrations showed the requirements at 12.2, 11.7, 12.3, and 11.2 g kg−1, respectively. Dietary inclusion of 12.5 g kg−1 histidine is recommended for fingerling C. punctatus for optimum growth, hematological parameters, and antioxidant activities.