Effects of diets formulated with different combinations of novel feed ingredients on growth performance, apparent digestibility, digestive enzymes and gene expression activities of Pacific white shrimp, Penaeus vannamei

A feeding experiment lasting 8 weeks was conducted to assess the effects of diets formulated with different combinations of novel feed ingredients in replacing fish meal (FM) and to assess the impact on growth performances, apparent digestibility coefficients (ADC), digestive enzyme and gene expression activities (IGF-I, IGF-II) of Penaeus vannamei. Five isonitrogenous (36%) and isolipidic (6%) diets, viz. diet 1 (control diet), used FM as the main protein source; diet 2, FM was replaced by poultry by-product meal (PBM) and single-cell protein (SCP) (1:1); diet 3, FM was replaced by insect meal (IM), rapeseed meal (RM) and single-cell protein (SCP) (1:1:1); diet 4, FM was replaced by fish waste (FW), peanut meal (PM) and single-cell protein (SCP) (1:1:1) and diet 5, FM was substituted by poultry by-product meal (PBM), single-cell protein (SCP), insect meal (IM), fish waste (FW), peanut meal (PM) and rapeseed meal (RM) (1:1:1:1:1:1), were formulated and fed to Penaeus vannamei. Juvenile shrimps that had been raised in nurseries (1.05 ± 0.03 g) were put in the experimental tanks in triplicate, with 35 shrimp per tank. Among the dietary groups, significantly (p < 0.05) higher final weight and SGR were observed in shrimp fed with diet 5, which was not significantly different from diet 1 and diet 3. The lowest FCR and significantly higher PER were obtained in shrimp fed with diet 5, and it was not significantly different from diet 1. Significantly (p < 0.05) higher whole-body crude protein and whole-body crude lipid was observed in shrimp fed with diet 5. Significantly higher (p < 0.05) dry matter digestibility and crude protein digestibility was observed in diet 1 and diet 5. In the hepatopancreas of shrimp, significantly higher (p < 0.05) amylase and protease activity was observed in shrimp fed with diet 5. Similarly, in the intestine of shrimp, significantly higher amylase and lipase activity was also observed in shrimp fed with diet 5. The significantly higher IGF-I and IGF-II gene expression activity was found in shrimp fed with diet 1 and diet 5. Thus, the present study concluded that a mixture of PBM, SCP, IM, RM, PM and FW (1:1:1:1:1:1) serves as a good combination diet to totally replace FM in shrimp feed without compromising growth performance, nutrient utilization of Pacific white shrimp (P. vannamei).