Effect of two kinds of insect protein source as substitute for fish meal on growth, body composition and protease activity of juvenile yellow catfish Pseudobugrus fulvidraco.

Using yellow mealworm meal(YMM) and pupa meal(PM) as dietary protein to replace fish meal at two levels of 50%(50YMM 50PM) and 100%(100YMM 100PM),with 100% fish meal as a control group,five kinds of feeds were prepared,which were the same protein level 40%.A 36 day feeding trial was carried out to examine growth parameters and feed utilization,body composition and protease activity in the juvenile yellow catfish(initial body weight 1.52±0.29 g·fish-1) fed with those formulated feeds.The results showed that there were significant differences in protein digestibility and feed efficiency between the control group and the other groups of juvenile yellow catfish(P0.05).The weight gain ratio was significantly lower in the fish fed with the 100YMM and 100PM than the fish fed with 50YMM and 50PM.There was no significant difference in protein digestibility among the fish fed with the formulated feeds of 100YMM,50YMM and 50PM(P0.05); The fish fed with 100PM had significantly lower protein digestibility than the other groups.Excepting no significant differences in feed efficiency between fish fed with 50YMM and control group(P0.05),there were significantly higer feed efficiency in the fish fed with 100YMM,100PM and 50PM than the fish in control group(P0.05).Except the body water content,only the crude protein of fish with fed 100PM was signifcantly lower than the other groups(P0.05),but there was no significant difference among the fish with fed 50YMM and 100YMM(P0.05).The crude fat of fish fed with 100PM and 50PM was signifcantly higer than the other groups(P0.05).Excepting no significant difference in the crude ash between 50YMM and control group(P0.05),there were significant difference among the other groups(P0.05).The protease activities in hepatopancreas,stomach and intestine of yellow catfish juvenile in control group were highest among fish fed with the formulated feeds.Only pepsin activity was significantly different,but there was no significant difference between 50YMM and control group(P0.05).And the protease activity was significantly higher in hepatopancreas and intestine of fish in control group than in 50YMM and 50PM(P0.05).