Effect of dietary replacement of fish meal protein with silkworm pupae on the growth performance, body composition, and health status of Cyprinus carpio var. specularis fingerlings

Abstract

The experiment was conducted to evaluate the effects of partial replacement of fish meal(FM)with silkworm pupae(SWP)on juvenile Cyprinus carpio var.specularis[(12.10±0.89) g].FM diet(fish meal 10%,silkworm pupae 0%,CP 36.18%,EE 5.18%)and SWP diet(fish meal 5%,silkworm pupae 5.5%,CP 35.38%,EE 5.06%)were formulated to feed the fish three times daily to visual satiety in indoor circulating water system for 61 days.The results showed that final body weight(FBW),weight gain rate(WGR),special growth rate(SGR),protein efficiency ratio(PER),feed conversion ratio(FCR),survival rate(SR)of the SWP group and FM group were not significantly different(P0.05),while no difference was found in condition factor(CF),viscerossomatic index(VI),hepatosomatic index(HI),spleen index(SI),intestine index(II),as well as the content of moisture,crude lipid,crude protein,crude ash of the fish tissue(P0.05).The contents of Lys in whole body and Tyr in muscle of SWP group were significantly lower than those in FM group(P0.05).The contents of C14∶ 0,C16∶ 1n-7 and C18∶ 1n-7 in muscle of SWP group were significantly lower than those in FM group,and the contents of C18∶ 3n-3 and ∑n-3PUFA in muscle of SWP group were significantly higher than those in FM group(P0.05).On the other hand,the contents of C18∶ 3n-3 and C22∶ 5n-3 in hepatopancreas of SWP group were significantly higher than those in FM group(P0.05).No significant difference was found in serum biochemical indices,index of atherogenicity(IA)and index of thrombogenicity(IT)between the two groups(P0.05).There are no significant differences in mucosa amount,mucosa height,mucosa width and submucosa thickness of foregut and midgut(P0.05),however,the muscular coat thickness of foregut was significantly lower in SWP group than FM group(P0.05).It is concluded that silkworm pupae is an acceptable alternative animal protein source,which can replace up to 50% of fish meal protein in C.carpio var.specularis diet without significant adverse impact on the health status,althought it affects the tissue amino acid and fatty acids profiles,and has a tendency to promote the growth performance and feed utilization.