The Effects of Dietary Vitamin C Sources and Levels on Immunity of Juvenile Sea Cucumber(Apostichopus japonicus)
WANG Ji-qiao1,SU Jiu-wang1,ZHANG Kun1,JIANG Yu-sheng1,ZHANG Jian-cheng2,LIANG Zhi-jun3(1.Life Science and Technology Institute,Dalian Fisheries University,Dalian 116023,China;2.Dalian Pacific Seafood Co.,LtD,Dalian 116045,China;3.Liaoning Bureau of Fishery Port Supervision,Dalian 116000,China)
Few studies have been reported on effects of dietary vitamin C sources and levels on growth and immunity of juvenile sea cucumber(Apostichopus japonicus),though vitamin C as an essential micronutrition for animals is widely added to feed in fish and shrimp.The sea cucumber juveniles averaging 2.29 g in body weight were randomly stocked into 39 plastic tanks of each 45 cm×31 cm×30 cm at rate of 15 individuals per tank and fed formulated feed containing 7.63% crude protein(corn gluten as only protein source)and 3.89% crude fat supplemented with 5 levels(0,500,1000,2000 and 4000 mg/kg diet)of L-ascorbyl-2-polyphosphate(LAPP),L-ascorbyl palmitate(LAP)or L-ascorbyl-2-monophosphate-magnesium(APM)to investigate the effects of dietary vitamin C sources and levels on immunity of the juveniles with triplication at a water temperature of 11.0～14.0 ℃ for 90 days.Higher superoxide dismutase(SOD)and lysozyme(LS)activities were found in the juveniles fed the diets supplemented with the vitamin C than those in the juveniles in the control groups(P0.05).The juveniles fed the diets supplemented with LAPP had the maximal SOD activity(0.514 U/ml),followed by the juveniles fed the diets supplemented with APM(0.458 U/ml)and the next in the juveniles fed the diets supplemented with LAP(0.438 U/ml),30.18%,17.31% and 12.21% higher than those in the control groups.There were the maximal LS activity in the juveniles fed the diets supplemented with LAPP(5.435 U/ml),followed by the juveniles fed the diets supplemented with APM(5.297 U/ml)and the next in the juveniles fed the diets supplemented with LAP(4.161 U/ml),101.39%,96.29% and 54.17% higher than those in the control groups(2.699 U/ml).The stability to lysosome membrane was in a descendent order arranged for the vitamin C as the following:LAPPLAPAPM.Second-degree polynomial regression revealed that the maximal stability to lysosome membrane,and lysozyme and SOD activities were observed in the juveniles fed the diets supplemented with LAPP at a rate of 2233~3125 mg/kg,APM of 1677~2425 mg/kg and LAP of 2500~2600 mg/kg.The results come to the conclusion from the improvement of immunity in the sea cucumber that the optimal dietary vitamin C micronutrition is of LAPP.
【Fund】： 辽宁省教育厅计划项目(20060186);; 辽宁省海洋与渔业厅项目
【CateGory Index】： S917.4
【CateGory Index】： S917.4