Effect of protein source on growth of early juvenile redclaw crayfish Cherax quadricarinatus (Decapoda, Parastacidae)

Abstract

We examined the effect of dietary protein sources on survival and growth of early juvenile C. quadricarinatus. Five isoproteic (35%) and isocaloric diets containing various proportions of fish meal:soybean meal as protein sources were assayed. Fishmeal was replaced by soybean meal as a protein source at 0, 25, 50, 75 or 100% of the protein content. Survival and weight gain were determined after 90 days. The content of protein and lipids in the hepatopancreas and abdominal muscle of surviving animals were determined. The highest weight gain was observed with the replacement of 50% of fish meal by soybean meal, this weight gain was significantly higher than that of diets having only one protein source. There were no significant differences in protein content for either the hepatopancreas and muscle among all diets. Diets with 50% or 25% soy meal produced higher lipid levels in the hepatopancreas, while the replacement of fish meal by soy meal in the 50% and 75% diets showed the highest lipid levels in muscle. Based on results of this study, for culture purposes, and considering the high cost of fish meal, replacing 50% of the protein content of a fish meal diet with soybean meal would yield the best growth at the lowest cost.