Study On Application Effects Of Dietary Chitosan Oligosaccharide In Breeding In Sea Cucumber Apostichopus Japonicus

This study was conducted to investigate the effects of different treatments process and different feeding modes of dietary chitosan-oligosaccharides(COS)on growth,digestive enzyme,immunity and intestinal bacteria of sea cucumber(Apostichopus japonicus).Meanwhile,in order to bridge the application of COS into production better,the effect of different feed shape on the feeding with COS on growth performance and immune response of sea cucumber was further researched.On the basis,to find out the suitable program of COS application for pilot production,the feasibility of the application of COS was verified.Experimental methods for different treatment processes and different feeding modes of COS,Experimental preparation of three kinds of pellets: the basic feed,basal feed added 0.5% COS,basal feed added 1.5% coated COS,and the effective content of COS in the latter two is the same.The experiment is divided into five groups,set up two experimental designs.(1)Experiment 1,COS different treatment group settings: the basal diet was used as control group(G0);1.50% coated COS added group(G1);0.50% COS added group(G2).(2)Experiment 2,COS different modes of feeding group settings: basal feed continuous feeding(G0);0.50% COS feed continuous feeding(G2);0.50% COS fed for 5 days,basal diet fed for 10 days at intervals(G3);0.50% COS feed and basal feed interval 10 days feeding(G4).A 60-day feeding experiment was carried out the sea cucumber with the initial average weight of 2.33 g.The results showed:(1)Compared with the control group,the growth performance of the treatment group was not significantly different(P > 0.05),but the growth index of each treatment group was higher than the control group.The activity of lipase and protease in G1 group was significantly higher than that in control group(P<0.05),G2 group compared with the control group has increased but not significant(P > 0.05),there was no significant difference in amylase in each treatment group(P > 0.05).In addition to NOS,the immune parameters of G1 group were significantly higher than the control group(P<0.05).(2)Compared with the control group,there were no significant differences in the growth performance between the treatment groups(P > 0.05),but the growth indexes of the treatment groups were better than those in the control group,G2 group best.The levels of lipase and protease in G2 and G3 groups were significantly higher than those in the control group(P<0.05).There was no significant difference in the amylase in each treatment groups(P > 0.05).In addition to NOS,G2 and G3 groups were significantly higher than the control group of immune indicators(P<0.05).As a result of the experimental experiment 1 and the experiment 2,the effect of coated COS on the growth performance,digestive enzyme and non-specific immune index was the best,but comprehensive consideration,COS for continuous feeding and interval of 10 d feeding method is more appropriate.In addition,there was no significant difference with attack test in each treatment groups(P > 0.05),the lowest mortality rate in the G1 group and the highest in the control group.In summary,G1 group had the best effect of promoting growth and immunity,followed by G2 group and G3 group.The effects of COS as an immunostimulants on the intestinal flora of sea cucumber were analyzed by high throughput sequencing.The results showed: The bacterial diversity and colonyabundance of COS were higher than those in the control group.In phyla level,the dominant bacteria are all strains of Proteobacteria.Among the dominant species,the COS addition group had a great change compared with the control group,In the control group,the highest proportion was the genus planctomycete,the lowest was genus Bacillus,and added COS groups to the contrary.The results showed that COS had an effect on the composition of intestinal flora.In summary,the addition of COS in the feed can increase intestinal bacterial diversity and relative abundance and promote the proliferation of beneficial bacteria.Experiment on the addition of COS in different forms of feed.The feeding trial of different shape feed with COS lasted for 50 days.The results showed the addition of COS to different forms of feed had no significant effect on the growth(P > 0.05),the order of weight of sea cucumber showed: COS Powder group> Control powder group>COS Pellet group.The immune index of COS pellet groups were significantly higher than other groups(P<0.05),the immune index of COS powdery material groups were significantly higher than the control(P<0.05).In summary,the shape of powder with COS on the feeding is more suitable for promotion in production.Combining these results of COS,the pilot test was conducted on COS in the enterprises.The addition of COS to the feed can promote the growth performance of the sea cucumber,and can enhance the resistance of the sea cucumber.It can be seen that COS are feasible in the breeding of sea cucumber.