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海洋与湖沼 2012
EFFECTS OF DIETARY CHITOSAN ON GROWTH PERFORMANCE, BODY COMPOSITION AND NON-SPECIFIC IMMUNITY OF JUVENILE ONCORHYNCHUS MYKISS
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Abstract:
Rainbow trout was cultured widespread all around the world, but the healthy of rainbow trout was generally inhibited by high-density culture. A 50-d feeding trial was carried out to investigate the effects of dietary chitosan on growth performance, body composition and non-specific immunity of juvenile Oncorhynchus mykiss (98.26±0.25)g]. Five isonitrogenous and isoenergetic diets were formulated by adding 0% (D0, control group), 0.25% (D1), 0.50% (D2), 1.00% (D3) and 2.00% (D4) chitosan to the basal diet, in which casein and fish meal were used as the protein source and fish oil as the lipid source, respectively. Results showed that: weight gain rate (WGR) and specific growth rate (SGR) increased whereas feed conversion ratio (FCR) decreased significantly (P<0.05) with chitosan addition No significant differences were found among chitosan-supplemented groups (P>0.05). Viscerosomatic index (VSI) decreased (P<0.05) with dietary chitosan supplementation (P<0.05). However, there were no statistical differences in hepatosomatic index (HSI), spleensomatic index (SSI), condition factor (CF) or survival ratio (SR) (P>0.05). Lipid content in whole fish, muscle and liver were decreased obviously by dietary chitosan (P<0.05) , while no change existed in moisture and protein contents (P>0.05). Alkaline phosphatase (ALP) activity in serum of D3 and D4 groups was decreased significantly (P<0.05) and there were no differences among other groups (P>0.05). Serum acid phosphatase (ACP) activity decreased as dietary chitosan supplementation level increased (P<0.05), while lysozyme (LZM) activity was increased (P<0.05). Total antioxidant capacity (T-AOC) of D4 group was significantly higher than that of the control and D1 group (P<0.05) and no differences were found among other groups (P>0.05). Superoxide dismutase (SOD) was not affected by dietary chitosan (P>0.05).
