饲料中脂肪及乳化剂含量对仿刺参幼参生长和体组成的影响

Effects of dietary lipid and emulsion levels on growth and composition in juvenile sea cucumber Apostichopus japonicus

在实验室条件下研究了饲料中脂肪及乳化剂含量对仿刺参Apostichopus japonicus幼参生长和体组成的影响。试验1，在11．5—21．5℃水温下，将体质量平均为2．71g的仿刺参放养在容量为50L的水槽（45cm×31cm×30cm）中，投喂以鱼粉和玉米蛋白为蛋白源，深海鱼油为脂肪源的膏状饲料（粗蛋白质的质量分数为19．8％，粗脂肪的质量分数分别为2．80％、3．65％、4．50％、5．35％、6．20％和7．05％）。经60d饲养，结果表明，饲料中脂肪的质量分数为6．20％时，幼参的特殊生长率、表观脂肪消化率与脂肪含量的乘积及体内高度不饱和脂肪酸含量最高。二次回归拟合曲线表明，幼参饲料中脂肪的适宜质量分数为5．35％-7．05％，最适为5．88％。试验2，饲料中蛋白质和脂肪质量分数分别为24％和5．0％（大豆油作为脂肪源），在脂肪中分别加入0、5％、10％和15％的大豆卵磷脂作为脂肪乳化剂，饲养体质量平均为5．48g的仿刺参。经45d饲养，结果表明，10％的乳化剂组幼参的特殊生长率和脂肪表观消化率显著高于其他各组（P〈0．05），该浓度的乳化剂对幼参肠道萎缩的抑制性效果较好。本研究表明：饲料中适宜的脂肪含量能有效地促进仿刺参的生长，提高体内多不饱和脂肪酸的含量（特别是在适宜的温度下）；饲料中含有丰富的多不饱和脂肪酸可促进仿刺参生长，增强其体质。

Two feeding experiments were conducted to elucidate the effects of dietary lipid and emulsion levels on growth and approximate composition in juvenile sea cucumber （Apostichopus japonicus ）. In experiment 1, juvenile sea cucumber weighing 2.71 g in body weight was stocked into 24 plastic tanks of each 45 cm × 31cm × 30 cm and fed the 19.8% crude protein diets containing 2.80%, 3.65%, 4.50%, 5.35%, 6.20% and 7.05% of fat （deep sea fish oil） at 11.5 -21.5 ℃ for 60 days. The sea cucumber fed the diet containing 6.20% of oil was found to have the maximal special growth rate （SGR）, apparent digestible fatty levels and polyunsaturated fatty acid levels （ % ） in body. A second order polynomial regression model between SGR （Y） and dietary fatty levels （X） （Y= -0. 029X2 ＋0. 341X ＋ 0. 071 ） suggested that the optimal dietary fat level was recommended to vary from 5.35% to 7.05%, and the fatty level of 5.88% which corresponded to the maximum growth. In experiment 2, soybean phospholipd as emulsion was added to the diets at a rate of 0, 5%, 10% and 15% of soybean oil to prevent juvenile sea cucumber from envisceration at water temperature of 11.5 - 14.5 ℃ for 45 days. The sea cucumber fed the diet containing 10% of emulsion showed significant higher special growth rate than that in other groups and had significantly higher apparent digestibility of fatty levels than those in the other groups （P 〈 0. 05）. Soybean phospholipd was found to act as good emulsion to prevent sea cucumber from intestines atrophy.