Effect of fish meal replacement with toasted guar meal on growth, food conversion, digestive enzyme activity and final carcass composition of rohu,Labeo rohita

Abstract

A growth trial was conducted for 60 days in 4 × 4 m outdoor cement tanks with soil base to evaluate growth, feed conversion efficiency, carcass composition and digestive enzyme activity of rohu, Labeo rohita, fed diets incorporated with guar meal replacing fish meal. The isonitrogenous and isocaloric diets used were—a fish meal based diet (Control) and diets with fish meal replaced at 30%, 60% and 90% levels with guar meal. The growth parameters, feed conversion and protein efficiency ratio, survival and condition factors did not differ significantly among the different treatments. While the activity of the digestive enzymes in the hepatopancreas did not differ (p > 0.05) among the treatments, the activity of digestive enzymes estimated in the intestine showed reduction at higher levels of guar incorporation. Carcass composition analysis revealed the highest moisture and lowest crude protein, fat and gross energy levels in fish from 90% replacement group. Lowest moisture and highest crude protein, fat and energy levels were observed in fish from 30% replacement. The study indicated the possible use of processed guar meal as a fish meal substitute in the diet of rohu, resulting a reduction in feed cost without compromising on fish growth and quality.