Effects Of Dietary Enzyme On Growth, Digestion And Immunity Capabilities Of Sea Cucumbers(Apostichopus Japonicus)

Part1 A 56-day feeding trial was conducted to evaluate the effect of several different enzymes on growth performance, body composition, immunity capabilities, and immune enzyme activities and heat shock protein 70 content under the stress of ammonia nitrogen of sea cucumbers with initial body weight of(4.02±0.04)g.Appropriate xylanase, cellulose, amylase and compound enzyme were added into control diet to formulate 5 experimental diets(D1, D2, D3, D4, D5, D1 as control group, without enzyme). The results showed that: growth performance was significantly improved by dietary enzyme(P< 0.05). Weight gain rate(WGR) of D2-D5 groups were increased 18.74%, 9.05%, 3.17% and 2.02% compared to D1 group, respectively. Crude protein of body wall was increased by dietary xylanase significantly, and crude protein, crude fat and crude ash were significantly improved by dietary cellulase, amylase and compound enzyme(P < 0.05). Lysozyme(LZM),superoxide dismutase(SOD) and catalase(CAT) activities of coelomic fluid were increased significantly by dietary enzyme. LZM,SOD and CAT activities of D4 group were increased 4.71%, 7.68% and 47.33%, compared with the control group,respectively. During ammonia nitrogen stress experiment of 120 h, LZM, SOD, CAT activities and HSP70 content showed a tendency of increasing first and then decreased,whereas dietary enzyme groups were higher than the control group.(conclusion)In conclusion, dietary enzyme can significantly improve the growth performance, body composition, and immunity capability and disease resistance. Additionally, xylanase improves the growth, and amylase promotes immune function more obviously.Part2 A 56-day feeding trial was conducted to evaluate the effect of xylanase on growth performance, body composition, digestive enzyme activity and immunity capabilities of sea cucumbers with initial body weight of(7.73±0.09)g. Six isonitrogenous and isoenergergetic diets were formulated by adding0,0.03%,0.06%,0.09%,0.12% and 0.24% xylanase to the basal diet. The results showed that:1) Growth performance was significantly improved by dietary xylanase(P< 0.05). Compared to control group, weight gain rate(WGR) of D0.03-D0.24 groups were increased 11.63%、22.02%、39.63%、29.31%�'� 22.43%. 2) Crude protein of body wall was increased by dietary xylanase significantly. Crude fat and were significantly improved by dietary 0.06%- 0.24% xylanase(P < 0.05). Crude ash revealed no noticeable difference among all treatments(P> 0.05). 3) Digestive enzyme activity of the intestine was increased by dietary xylanase significantly.Trypsin activities was increased by dietary 0.06%、0.09% and 0.12% xylanase significantly. Amylase activities was increased by dietary 0.24% xylanase significantly.4)LZM, SOD activities showed a tendency of increasing first and then decreased with the increasing dietary xylanase. LZM, and CAT activities of coelomic fluid were increased significantly by dietary 0.06% and 0.09% xylanase. Compared to control, CAT activities show increased but no noticeable difference by dietary xylanase.In this experiment, the addition of xylanase can improve growth performance, body composition, digestive enzyme activity and immunity capabilities of sea cucumbers. NLIN curve regression of WGR indicated that the optimal level of xylanase for sea cucumbers diets was 0.0884%.