Reduced dietary protein levels do not impair growth and muscle composition in juvenile red swamp crayfish,Procambarus clarkii(Girard, 1852): Implications for pond culture in China

Abstract

High dietary protein input in aquaculture leads to suboptimal growth and increased production costs. Limited knowledge on dietary protein requirements of Procambarus clarkii in pond culture has hindered the scientific expansion of optimum feeding strategies. We evaluated the effects of reduced dietary protein levels (from 30% to 26%) on the growth performance (weight, length, GSI, HSI, SGRw, SGRL and muscle weight) and muscle composition (crude protein, lipid, ash and moisture) of juveniles in eight concrete ponds cultured with Hydrilla verticillata. No significant differences were observed in the growth performance between the two treatments. P. clarkii fed a diet containing 26% protein had significantly higher crude protein and ash contents, whereas no significant differences existed in the lipid contents. The δ13C and δ15N values of P. clarkii and its food resources were not significantly affected by dietary protein levels. However, the Bayesian mixing model identified the mean contribution of H. verticillata in P. clarkii growth increased from 37.34% to 41.93% when dietary protein levels decreased from 30% to 26%. Considering the significant contribution of natural foods, we encourage the reduction in dietary protein levels from 30% to 26% in ponds to further reduce the production costs.