The Effects Of Chitosan-oligosaccbarides On The Growth Performances, Non-pecitify Enzymes And Intestinal Bacteria Flora Of Takifugu Rubripes

This study was conducted to investigate the effects of chitosan-oligosaccharides(COS) on growth, digestive enzyme and intestinal bacteria flora of tiger puffer(Takifugu rubripes). Four experimental diets were formulated by supplementing the basal diet with COS(0.0%, LC0; 0.05%, LC1; 0.1%, LC2; and 0.2%, LC3). After 56-day feeding trial, the result illustrated that: Significant effects were found on growth parameters such as weight gain(WG), specific growth rate(SGR), intestinal-somatic index(ISI) and feed conversion ratio(FCR) of various groups of tiger puffer, growth parameters of fish fed with LC3 was significantly higher than other groups while FCR was significantly lower than others(P < 0.05). This study found no significant difference in condition factor(CF), hepatosomatic index(HIS), viscerosomatic index(VSI), survival rate, muscle moisture, crude protein, crude lipid and ash of tiger puffer among all treatment groups(P > 0.05).The feeding trial lasted for 56 days. The results showed as follows : Dietary supplementation of chito-oligosaccharides significantly improved the contents of blood platelet(P < 0.05); The activity of each group is increased with the chitosan-oligosaccharides increased, dietary supplementation of chitosan-oligosaccharides improved the activities of alkaline phosphatase, lysozyme, cata-lase and superoxide dismutase in serum(P < 0.05);Dietary supplementation of chitosan-oligosaccharides remarkable improved the contents of the cata-lase and superoxide, the activity of malondialdehyde was significantly lower(P < 0.05)with the contrastdismutase and malondialdehyde activity in livewith the contrast(P < 0.05).After 56-day feeding trial, the result illustrated that: The amylase activity of intestine showed no significant differences(P>0.05), but protease and lipase were significant differences(P < 0.05), dietary supplementation of COS significant increased the intestinal protease and lipase activity of tiger puffer(P < 0.05). The intestinal bacterial flora was used high-through sequencing technique. The results showed that the intestinal bacterial flora Shannon index in control was significantly higher than LC1, LC2 and LC3(P < 0.05). In phyla level, the Proteobacteria ratio in LC3 was significantly higher than other groups, and the percent of Bacteroidetes, Acidobacteria and Firmicutes in LC3 were significantly lower than other groups(P < 0.05). In the genus level, the percentage of Aliivibrio and Bacillus in LC3 was significantly higher than other groups, the percentage of Faecalibacterium and Escherichia and Bacteroides was significantly lower than other groups(P < 0.05).In conclusion, results suggested that dietary intake containing chitosan-oligosaccharides could enhance the growth performance, non-specific immunity function, improve intestinal digestive enzymes activity and improve intestinal bacterial flora composition of tiger puffers.