Effects of dietary docosahexaenoic acid(DHA)content on growth performance and nutrient composition in body wall of adult sea cucumber Apostichopus japonicus
1.Key Laboratory of Mariculture&Stock Enhancement in North China's Sea,Ministry of Agriculture,Dalian Ocean University,Dalian 116023,China;2.Liaoning Province Marine Environmental Forecasting Center,Shenyang 110001,China;3.The National Fisheries Techonology Extension Center,China Fisheries Society,Beijing 100125,China
Abstract: Adult sea cucumber Apostichopus japonicus with body weight of(73.49±1.26)g were reared in a 100 L tanks at stocking density of 20 individuals and fed diets containing 0.02%,0.30%,0.60%and 1.20%of docosahexaenoic acid(DHA)at water temperature of(12±2)℃for 121 d to investigate the effects of dietary DHA levels on growth performance and nutrient composition in body wall of sea cucumber.The maximal weight gain rate (WGR)was observed in the sea cucumber fed diets containing 0.60%DHA,significantly higher than that in the animals fed diet containing 0.02%DHA(P＜0.05).Dietary DHA levels led to affect composition in body wall of sea cucumber,significantly higher eicosapentaenoic acid(EPA),DHA and n-3 polyunsaturated fatty acid(n-3 PUFA)concentrations in sea cucumber fed diets containing 0.30%-1.20%DHA than that in sea cucumber fed diets containing 0.02%DHA(P＜0.05).The EPA/DHA and n-3/n-6 PUFA were significantly elevated with dietary DHA level increase(P＜0.05).The maximal phenylalanine(Phe),tyrosine(Tyr),isoleucine(Ile),valine (Val),methionine(Met)and total essential amino acids(TEAAs)contents were observed in body wall of sea cucumber fed diet containing 0.30%DHA,significantly higher than that in sea cucumber fed diet containing 0.02% DHA(P＜0.05),without significant differences in the ratio of TEAA to total nonessential amino acids(TNEAAs) among the four groups.It is recommended that optimal DHA requirement be 0.30%-0.60%dry diet in adult sea cucumber,since 0.60%dietary DHA results in the maximal WGR and deposition of essential fatty acids and amino acids in sea cucumber.
2017, Vol. 32 
