饲料中添加蛋氨酸硒对仿刺参幼参存活、生长及免疫指标的影响

在水温为14.0～8.0℃、盐度为31～32和pH为7.5的条件下,将初始体质量为1.30～1.68 g的仿刺参Apostichopus japonicus幼参饲养在塑料水槽（40 L）中,投喂蛋氨酸硒添加量分别为0、0.2、0.4、0.6、0.8、1.0 mg/kg的饲料60 d,每种饲料设3个重复,每个重复组放15头仿刺参。试验结束后饥饿24h,测定仿刺参体质量的特定生长率（SGR）,体腔液中过氧化氢酶（SOD）、超氧化物歧化酶（CAT）、酸性磷酸酶（ACP）的活力,体壁干物质和肠干物质中硒的含量。结果表明：各组仿刺参的成活率为100%;当蛋氨酸硒添加量为0.6 mg/kg时,仿刺参幼参的SGR最大,且显著高于对照组（P〈0.05）,当硒添加量为1.0 mg/kg时,仿刺参幼参的SGR值最小;当硒添加量为0.6 mg/kg时,仿刺参对饲料干物质和粗蛋白的表观消化率最高,且显著高于对照组（P〈0.05）;各试验组仿刺参体壁干物质中蛋白质含量均显著高于对照组（P〈0.05）,且当硒添加量为0.4 mg/kg时,蛋白质含量最高;当硒添加量为0.6 mg/kg时,幼参肠中的硒含量最高,且显著高于对照组（P〈0.05）,但当硒添加量为0.4 mg/kg时,幼参体壁中的硒含量最高,其次为0.6 mg/kg硒组;除硒添加量为1.0 mg/kg外,各试验组仿刺参体腔液中的SOD、CAT值均显著高于对照组（P〈0.05）,添加量分别为0.8 mg/kg和0.4 mg/kg时达到最高,其次是0.6 mg/kg组;各试验组仿刺参ACP的活性均显著高于对照组（P〈0.05）,硒添加量为0.4 mg/kg时达到最高。研究表明,仿刺参幼参饲料中蛋氨酸硒的适宜添加量为0.4～0.6 mg/kg。

Effects of dietary selenomethionine levels on growth and some immune indices in juvenile sea cucumber Apostichopus japonicus

Juvenile sea cucumber Apostichopus japonicus with initial body weight of 1.30-1.68 g were stocked into 40 liter plastic tanks at a rate of 15 individuals per tank and fed the diets containing selenomethionine at a rate of 0 mg/kg（control group）,0.2 mg/kg（group A）,0.4 mg/kg（group B）,0.6 mg /kg（group C）,0.8 mg/kg（group D） and 1.0 mg/kg（group E） with triplication at water temperature of 14.0-8.0 ℃,a salinity of 30-32,and pH 7.5 for 60 days.Some growth indices and enzyme indices of the sea cucumber were measured after the experimental animals were starved for 24 hours at the end of the experiment.The results showed that there was no significant difference in survival of the sea cucumber in the experiment（P0.05）.The SGR,the crude protein content in dry mater in body walls,and protein apparent digestibility（%） were also significantly higher in the sea cucumber fed the diets containing 0.6 mg/kg selenomethionine than those in the control（P0.05）,while the poor SGR was observed in the sea cucumber fed the diets containing 1.0 mg/kg selenomethionine.The maximal selenium level was found in the intestine of the sea cucumber fed the diets containing 0.6 mg/kg selenomethionine,but was observed in the body wall of the sea cucumber fed the diets containing 0.4 mg/kg selenomethionine,significantly higher than that in the control group（P0.05）.The sea cucumbers fed the diets with 0.6 mg/kg selenomethionine had the maximal SOD activity.However,the maximal CAT and ACP activities were found in the coelomic fluid of the sea cucumber fed the diets containing 0.4 mg/kg selenomethionine,significantly than those in the control group.It is suggested that the optimum dietary selenomethionine supplementation should be 0.4-0.6 mg/kg in order to increase the growth performance and immunity in the sea cucumber.