Abstract: A 56-day feeding trial was conducted to evaluate the effect of xylanase on growth performance, body composition, digestive enzyme activity and immune enzyme activity of sea cucumber with initial body weight of(7.73±0.09)g. Juvenile sea cucumber were reared in cylindrical fiber glass tanks (70 cm×80 cm) at a density of 50 individuals per tank and fed six isonitrogenous and isoenergergetic diets containing 0, 0.03%, 0.06%, 0.09%, 0.12% and 0.24% xylanase with 3 replicates at water temperature of (19±1)℃. The results showed that there was significantly higher growth performance in the sea cucumber fed diets containing xylanase than that in the other groups(P<0.05), significantly higher weight gain rate (WGR) in the sea cucumber fed diets containing 0.03%-0.24% xylanase compared to control group(P<0.05). The sea cucumber fed the diet containing xylanase had significantly higher crude protein in body wall than the sea cucumber in the control group did(P<0.05). There was significantly higher crude lipid content in the sea cucumber in 0.06%-0.24% xylanase groups than that in the control group(P<0.05). The sea cucumber fed the diet containing xylanase at a rate of 0.06%-0.12% had significantly higher intestinal trypsin activities than the sea cucumber in the control group did(P<0.05). Amylase activity was found to be significantly higher in the 0.24% xylanase group than that in the other groups(P<0.05). The activities of lysozyme (LZM), catalase (CAT), glutamic-oxalacetic transaminase (AST), glutamic-pyruvic transaminase (ALT) and superoxide dismutase (SOD) were shown an increasing tendency first and then decrease with the increasing dietary xylanase, significantly higher LZM, and CAT activities in coelomic fluid of sea cucumber fed the diet containing xylanase at dose of 0.06%-0.12%(P<0.05). The findings indicate that the addition of xylanase leads to improve growth performance, body composition, digestive enzyme activity and immunity capabilities of sea cucumber, and that supplementation of xylanase at a dose of 900 mg/kg is of the optimal level for sea cucumber by Broken-line regression of WGR.
2018, Vol. 33 
