Effect of combined fish meal : soybean meal ratio, vitamin C and fish oil supplementations in diet on the growth and reproduction of red swamp crayfish, Procambarus clarkii (Crustacea: Decapoda)

Fish meal (FM), vitamin C (VC) and fish oil (FO) play important roles in the growth and reproduction in aquatic animals. To determine the optimum dietary combinations of FM:SM (soybean meal) ratio, VC and FO supplementations for the growth and reproduction of female crayfish Procambarus clarkii, we used the L9 (33) orthogonal array, which arranged three factors varied at three levels (FM:SM at 1:3, 1:2 and 1:1.5; VC supplementation at 0.02%, 0.04% and 0.06%; FO inclusion at 1.90%, 2.85% and 3.80%). Range analysis showed that the highest weight gain (WG) of the crayfish occurred at FM:SM of 1:1.5, VC supplementation of 0.04% and FO inclusion of 1.90%, and the maximum gonadosomatic index (GSI), egg laying amount (ELA) and spawning rate (SR) were obtained at FM:SM 1:1.5, VC supplementation 0.06% and FO inclusion 3.80%. Analysis of variance indicated that all the three factors had no significant effects on WG. Fish oil supplementation significantly affected GSI, ELA and SR (P < 0.05), while FM:SM did not significantly influence any of these indicators. Taking the cost into consideration, we suggest that a dietary FM:SM of 1:3, VC supplementation 0.06% and FO inclusion 3.80% might be the optimal combinations for the reproduction of P. clarkii.