The effect of replacing fish meal with fermented meal mixture of silkworm pupae, rapeseed and wheat on growth, body composition and health of mirror carp (Cyprinus carpio var. Specularis)

Abstract

To investigate the effect of fermented meal mixture of silkworm pupae, rapeseed and wheat (FMM) on growth and health of juvenile mirror carp (Cyprinus carpio var. specularis), fish meal (FM) was replaced with FMM where FMM was increasingly added in the diets by 0, 40, 80, 120, 160 g kg−1 and FM decreased accordingly to form five isonitrogenous (365 g kg−1 crude protein) and isolipidic (60 g kg−1 crude lipid) diets, being FM, T1, T2, T3 and T4 groups. 270 mirror carp (9.70 ± 1.02 g) were randomly divided into five groups (each group having three replicates) and fed for 58 days. Following termination of the experiment, the fish growth, body composition and health status were analysed. Growth, feed utilization and crude lipid content were negatively correlated with FMM levels in the diet. Increasing the FMM levels led to decreased serum TG, total cholesterol, LDL-c, MDA and SOD, while GOT and GPT increased. Relative expression of TNF-α1 and IL-6 genes in hepatopancreas increased in the T3 and T4 groups and the spleen index showed significant differences in the T2 and T3 groups. In conclusion, 40 g kg−1 FMM can be included into diets of juvenile mirror carp, while 80–160 g kg−1 FMM inclusion adversely affects the growth and health status of the fish.