Dietary vitamin E requirement for maximizing the growth,conversion efficiency,biochemical composition and haematological status of fingerling Channa punctatus

The effect of feeding graded levels of vitamin E (E₀, E₂₀, E₄₀, E₆₀, E₁₀₀, E₁₄₀, E₁₈₀, E₂₂₀, E₂₆₀) in nine casein–gelatin‐based isonitrogenous (450 g kg^?1 crude protein) and isoenergetic (17.97 kJ g^?1 gross energy) experimental diets was evaluated in fingerling Channa punctatus for 12 weeks. Growth, nutritional and haematological parameters were studied. Hepatic lipid peroxidation as thiobarbituric acid‐reactive substances (TBARS) was also assayed. The maximum absolute weight gain (AWG g/fish, 55), best feed conversion ratio (FCR, 1.32), protein retention efficiency (PRE, 40%) and energy retention efficiency (ERE, 76%) were achieved in fish fed on a diet supplemented with 140 mg vitamin E kg^?1 diet (E₁₄₀). A consistent decline in the hepatic TBARS concentration and an improvement in haematocrit (Hct) and haemoglobin (Hb) were displayed in fish fed on diets with increasing concentrations of vitamin E up to 140 mg kg^?1 (E₀–E₁₄₀), beyond which (E₁₈₀–E₂₆₀) a reverse trend in these parameters was evident. Based on the broken‐line regression and exponential analyses of AWG, FCR, PRE, ERE, Hb and Hct data, diets for fingerling C. punctatus should contain vitamin E in the range of 140–169 mg kg^?1 to maintain satisfactory fish performance.