Objective The aims of this experiment was to investigate the effects of inulin on the growth performance, digestive enzyme activity, metabolic function and non-specific immunity of juvenile Siniperca chuatsi.
Methods A total of 360 juvenile S. scherzeri with initital body mass of (7.40 ± 0.07) g were selected and randomly divided into 4 groups with 3 replicates per group and 30 fish per replicate. Using crushed expanded feed for mandarin fish as the experimental basal diet, four types of diets were prepared with inulin addition levels of 0% (control group), 0.5%, 1.0%, and 1.5%, respectively. The trial lasted for 60 days.
Results 1) The optimal growth performance of juvenile Siniperca chuatsi was observed at a dietary inulin level of 0.5%. At this level, final body mass (FBM), weight gain rate (WGR), and specific growth rate (SGR) significantly increased (P<0.05), while feed conversion ratio (FCR) decreased significantly (P<0.05). 2) The intestinal digestive enzyme activity of juvenile Siniperca chuatsi was imptoved at a dietary inulin level of 0.5%. The intestinal amylase (AMS) activity was significantly increased compare to control group (P<0.05), the intestinal lipase (LPS) and intestinal trypsin (TPS) activity was increased compare to control group(P>0.05). 3) Adding inulin to feed can promotes the serum lipid metabolism in juvenile Siniperca chuatsi. The setum triglyceride (TG) content significantly decreased at a dietary inulin level of 1.5%, the serum cholesterol (CHO) and low-density lipoprotein cholesterol (LDL-C) levels at a dietary inulin level of 0.5% were significantly reduced compared with control group, the serum high-density lipoprotein cholesterol (HDL-C) content at a dietary inulin lecel of 1.0~1.5% was significantly elevated compared with control group. 4)Juvenile Siniperca chuatsi showed the highest protein metabilism at a dietary inulin level of 0.5%. At this level, The alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity significantly decreased. 5)Adding inulin to feed can promotes the non-specific immunity in juvenile Siniperca chuatsi. The serum malondialdehyde (MDA) content of L2, L3 and L4 were significantly lower than that of control group (P<0.05). The serum alkaline phosphatase (ALP) and acid phosphatase (ACP) activities significantly increased at a dietary inulin level of 0.5% (P<0.05).
Conclusions Under the conditions of this experiment, Adding appropriate amounts of inulin to feed can promote the growth, digestion, metabolism and immunity of juvenile Siniperca scherzeri, and 0.5% inulin supplementation has a better effect.
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