Animal Nutrition and Feed Technology

Koi carp (Cyprinus carpio var. koi) were reared for 60 days in the laboratory under five dietary treatments (A, B, C, D and E) with varying crude protein levels. Diet ‘A’ was commercial pelleted feed (CP 30.30%), while diets B, C, D and E were formulated from locally available feed ingredients having CP percentage of 24.4, 27.23 35.24 and 43.00, respectively. There was significant (P<0.01) difference in body weight gain of Koi carp with values 27.55±0.03g, 28.72±0.06g, 30.7±0.2g, 33.62±0.5g and 38.0±0.04g in treatment A, B, C, D and E, respectively. The highest body weight gain was observed in treatment E (38.02±0.04g) and lowest in treatment A (27.55±0.32g). The feed conversion ratio (FCR) and specific growth rate (SGR) showed significantly (P<0.05) better performance in treatment E. Digestibility of nutrients viz; crude protein (CP) and ether extract (EE) were significantly (P<0.05) higher for diet E and D. Commercial pelleted feed (treatment A) was cost intensive compared to formulated feeds. The body composition of fish showed significant differences (P<0.05) in protein and lipid content with highest protein and lipid content in treatment E (64.84 & 23.97) and D (64.09 & 21.86). The gross energy (k cal/g) content of the body showed the same trend. The water quality parameters (temperature, pH, dissolved oxygen and total alkalinity) were within normal range. It was concluded that for growing stages of Koi carp a crude protein level of 35.44 to 43.0 percent was better for growth and carcass composition.