Influence of dietary phytic acid on the growth, conversion efficiency, and carcass composition of mrigal Cirrhinus mrigala (Hamilton) fry

The effects of phytic acid on growth, protein efficiency, feed conversion, and carcass composition of mrigal Cirrhinus mrigala fry (2.5-3.5 cm) reared indoors at 18-22 C in 70-L flow-through (1-1.5 L/min) circular tanks were examined. Fish were fed isonitrogenous (40% crude protein) and isocaloric (4.32 kcal/g) purified test diets in the form of moist cake containing different levels (0.5, 1.0, 1.5, 2.0 and 2.5%) of phytic acid (dodecasodium salt) at a rate of 4% body weight twice daily (0800 and 1600 h). The highest weight gain (94.87%), specific growth rate (1.58%), protein efficiency ratio (2.02), and best feed conversion ratio (1.21) were observed in fish fed the control diet containing no phytic acid. Live weight gain and specific growth rate were significantly reduced by dietary phytic acid inclusion above 1%. Dietary inclusion of phytic acid markedly influenced the carcass composition of the fish. Whole body crude protein and fat content declined significantly (P < 0.05) in fish fed diets containing phytic acid, while percentage of moisture and ash in these fish was significantly (P < 0.05) higher than fish in control diets.