Evaluation of formulated diets with different levels of marine protein mixtures in aquariculture of koi carp Cyprinus carpio var. koi (Linnaeus, 1758)

Abstract

A marine protein mixture of fish, squid, shrimp and clam meal in equal proportion was incorporated at different levels in the diets formulated and designated as P16, P19, P26, P33, P40, P47, P53 and P59 for koi carp. Triplicate groups of 10 fish each were fed with the experimental diets for 12 weeks and assessed for growth and body composition. On physical evaluation of the extruded feeds, above 80% dry matter retention for 4 h was evident in feeds P26 to P47. Feeds with more starch (wheat) P19 and P16 had stability of more than 90% and feeds with less starch, P53 and P59 had a stability of less than 70%. The body tissue of the experimental animals fed with P59 and P53 had significantly (p<0.05) high levels of polyunsaturated fatty acids (PUFA). Total ash in the body decreased with proportionate decrease in nutrient density. Biomass gain was similar with feeds P33, P40, P47 and P53. Growth as a function of incremental levels of marine protein mixtures in diet was linear. Diets containing 250, 300 and 350 g kg-1 protein is advocated for normal growth and 400 to 450 g kg-1 protein mixture are recommended to promote faster growth.