Isoleucine requirement of fingerling Channa punctatus (6.74 ± 0.09 g) was estimated by feeding seven trial diets (450 g/kg CP, 14.73 kJ/g DE) containing 3.8, 7.5, 11.3, 15.1, 19.3, 23.2 and 27.4 g/kg of isoleucine for 12 weeks. Growth and haematological parameters increased with the increasing concentrations of dietary isoleucine up to 16 g/kg. Carcass protein and fat increased significantly with the increasing concentrations of dietary isoleucine up to 16 g/kg and then stabilized. Moisture content showed reverse trend to that of carcass fat. Hepatosomatic index was found to be highest at 4 g/kg of dietary isoleucine. Viscerosomatic index and condition factor increased significantly with increasing levels of isoleucine up to 16 g/kg dry diet. Serum protein, lysozyme and superoxide dismutase activities were also found to increase significantly up to 16 g/kg dry diet. Significant reduction in alanine aminotransferase and aspartate aminotransferase activities was observed by increasing concentrations of dietary isoleucine up to 16 g/kg. Based on quadratic regression analysis of absolute weight gain, feed conversion ratio, protein retention and isoleucine retention efficiencies against varying concentrations of isoleucine, the optimum isoleucine requirement ranging between 17.95 and 18.39 g/kg dry diet, corresponding to 39.88–40.86 g/kg dietary protein, is recommended for maximizing growth of C. punctatus.

No abstract

Availability of species-specific nutritionally balanced feeds is the crucial player in determining the economic success and sustainable aquaculture operation. The nutritionally balanced meal must contain an adequate amount to meet the requirement of the species under culture (Ebeneezar et al., 2019). Dietary protein is the most valuable source of essential amino acids (EAAs) required for growth and tissue building (Luo et al., 2006). The inclusion of an optimized amount of quality protein in diets and its deposition in fish could reduce nitrogen waste and production costs (Ebeneezar et al., 2019;Thoman et al., 1999). Although most of the protein of diet is used for growth and development, it is essential to synthesize hormones, antibodies, enzymes and tissues. The quality of dietary protein depends on amino acid composition and utilization. Amino acids are indispensable to protein synthesis (Adesola et al., 2018;Wu et al., 2013). The growth and feed efficiency ratio depends on how close the dietary amino acids are to the requirement. The lack of essential amino acid results in improper utilization of protein and consequently reduces the growth and feed conversion efficiency (Anderson et al., 1995;Dairiki et al., 2007). Hence, information about the dietary amino acids needs is a prerequisite to the formulation of amino acid balanced diets to maximize fish production and prevent the deficiency sign (Glencross et al., 2007).

No abstract

No abstract