Effects of Different Algae Powders on the Growth, Body Composition and Digestive Enzyme Activity of Sea Cucumber(Apostichopus japonicus)

Abstract：This study was conducted to determine the effects of several algae powders on the growth,body composition and digestive enzymes activity of sea cucumber Apostichopus japonicus.A.japonicus (8 g) were fed with different diets made of Laminaria japonica,Ulva lactuca and Gracilaria lemaneiformis powders for 60 days with its growth index and digestive physiology index determined.The results showed that the growth performance of A.japonicus fed with diet of U.lactuca was the best (P＜0.05),significantly better than other two dietst (P＜0.05).The somatic protein content of A.japonicus fed with diet of U.lactuca and G.lemaneiformis was significantly higher than those fed with the diet made of L.japonica(P＜0.05).In terms of digestive enzymes activity,trypsin activity of the intestine of the sea cucumber fed with diet of U.lactuca was the highest (P＜0.05).On amylase activity,there was no significant difference between diets made of U.lactuca and G.lemaneiformis powders;however the activity of these two diets were significantly higher than that of L.japonica diet (P＜0.05)Lipase activity in the intestine of sea cucumber was the highest when feeding the diet of G.lemaneiformis power,which was significantly higher than that of sea cucumber fed with the diets made of other two algae (P＜0.05).The enzyme activity of animals fed with diet made of L.Japonica power was slightly lower than that of those fed with diet made of U.lactuca power,but not significantly (P＞0.05).Our findings indicated that U.lactuca can be used as the main ingredient of diets to meet the nutritional requirement of A.japonicus,and G.lemaneiformis can be used as auxiliary ingredient of diets to supply more raw material resources.