Effects of replacing fish meal with soybean meal on growth, body composition and digestive enzyme activities of juvenile Chinese sucker,<i>Myxocyprinus asiaticus</i>

TLDR

Six isonitrogenous diets with soybean meal replacing fish meal from 0 % to 100 % were fed to juvenile Chinese sucker for 8 weeks to evaluate growth and digestive enzyme responses. Replacing up to 40 % of fish meal protein with soybean meal did not impair growth or protein utilization, whereas higher replacement levels reduced growth performance, lowered body lipid content, and altered digestive enzyme activities.

Abstract

Six isonitrogenous diets (420 g kg−1 crude protein on dry matter basis) with six levels of soybean meal (SBM) inclusion (0, 112, 225, 336, 449 and 560 g kg−1) in substitution of fish meal (0%, 20%, 40%, 60%, 80% and 100%) were evaluated in Chinese sucker of 1.81 ± 0.01 g initial weight for 8 weeks. There existed a significant difference (P < 0.001) in fish weight gain, feed conversion ratio, feed intake, protein efficiency ratio and specific growth rate when the replacement level for fish meal protein was increased from 40% to 60%, indicating that up to 40% of fish meal protein could be replaced with SBM protein without causing reduction in growth and protein utilization. Lipid contents in the Chinese sucker body decreased significantly (P < 0.001) as dietary SBM increased. Digestive enzyme activities in the intestine and hepatopancreas of the fish were significantly different (P < 0.001) as the SBM protein replacement level was increased. Results of the present study appear to indicate that 40% FM can be replaced by SBM in practical feeds of Chinese sucker.