饲料中不同脂肪酸搭配对仿刺参幼参生长和体组分的影响

Effects of four dietary fatty acids on growth and proximate composition of juvenile sea cucumber Apostichopus japonicus

中文关键词: 仿刺参  脂肪酸  生长  消化率  体组分

英文关键词: Sea cucumber Apostichopus japonicus  Fatty acid  Growth  Digestibility  Proximate composition

中文摘要:

      在水温13.0-23.0 ℃下，将平均质量1.45 g的仿刺参Apostichopus japonicus幼参放养在容量50Ｌ(45 cm×31 cm×30 cm)的水槽中，投喂以鱼粉、虾糠和玉米蛋白为蛋白源，添加马尾藻粉、海泥、贝壳粉和黄原胶等粗蛋白1270%和粗脂肪548%的饲料。在饲料中含有不同比例的亚油酸（LA）、α-亚麻酸（LNA）、二十二碳六烯酸（22∶6n-3）（DHA）和二十碳五烯酸（20∶5n-3）（EPA），以橄榄油平衡脂肪含量，以贝壳粉平衡其他成分，配制成LA和LNA的比例分别为20∶0（S1）；20∶1（S2）；1∶2（S3）和2∶1（S4）；LA、LNA、DHA和EPA的比例分别为6∶1∶5∶0（S5）；10∶1∶30∶5（S6）和10∶5∶6∶1（S7）的膏状饲料。80d的饲养表明，幼参摄食只添加橄榄油（S1）、添加橄榄油和亚油酸（S2）的饲料时生长最慢，显著低于其他各组的幼参（P<0.05）；摄食只添加亚麻酸（S3）或亚油酸和亚麻酸（S4）的饲料时，生长较慢，二者差异不显著（P>0.05)，但均显著低于摄食添加DHA（S5）和EPA+DHA（S6）的幼参（P<0.05）；摄食添加上述4种脂肪酸（S7）饲料时，生长最快，即LA，LNA，DHA和EPA的比例为10∶5∶6∶1时，体壁最厚，肠道中淀粉酶和蛋白酶的有效活力最高，对饲料脂肪和蛋白质的消化率显著高于其他各组（P<0.05）。摄食实验饲料的仿刺参体内蛋白+脂肪+灰分的含量之和（平均85.79%）远大于初始刺参（79.70%）的相应之和，由高至低依次为：S2（90.57%）> S1（87.97%）> S3（85.78%）> S4（85.29%）> S7（84.19%）> S5（83.79%）> S6（82.97%）。仿刺参摄食后体内18碳脂肪酸含量呈负增长，而体内EPA的含量均呈正增长，且恒定变化在4.36%-6.83%之间，表明饲料中的18碳脂肪酸能转化为仿刺参体内的EPA。添加了4种脂肪酸的S4、S5、S6和S7组幼参肠过氧化氢酶的活力显著高于剩余组（P<0.05）；仿刺参生长较快时，体内过氧化氢酶活性较高，超氧化物歧化酶（SOD）则反之。

英文摘要:

      A feeding trial was carried out to evaluate the effects of dietary fatty acids on growth and proximate composition of juvenile sea cucumber Apostichopus japonicus. Juvenile sea cucumber weighing 1.45g in body weight was stocked into 42 plastic tanks of each 45 cm×31 cm×30 cm for 80 days and fed the commercial 12.70% crude protein and 5.48% crude fat diets containing various proportions of olive oil, linoleic acid (LA), linolenic acid (LNA), docosahexaenic acid (DHA), and eicosapentaenic acid (EPA) with a ratio of LA to LNA=20∶0 （S1）；20∶1（S2）；1∶2（S3）and 2∶1（S4）and with LA∶LNA∶DHA∶EPA=6∶1∶5∶0（S5）；10∶1∶30∶5（S6）and 10∶5∶6∶1（S7）at water temperature of 13.0~23.0 ℃. The sea cucumber fed the diets containing supplement of only olive oil (S1), both olive oil and LNA (S2) and LA and LNA (S3) was found to have the minimal special growth rate (SGR), significantly lower than the animals fed other diets(P < 0.05). There were significantly lower visceral-somatic ratio, and higher intestinal amylase and protease activities, and higher apparent digestibility in the juveniles fed the diet with a ratio of LA∶LNA∶DHA∶EPA= 10∶5∶6∶1（S7）(P < 0.05). Much higher total levels (85.79%) of protein, fat and ash were observed in the juveniles fed the experimental diets than in the initial juveniles(7970%), descendantly ranged as S2（90.57%）> S1（87.97%）> S3（85.78%）> S4（85.29%） > S7（84.19%） > S5（83.79%）> S6（82.97%）.While there was degrowth in LA+LNA levels in the juveniles fed the experimental diets, there was increase in EPA level, varying from 4.36%to 6.83% in the juveniles fed the experimental diets without supplementation of EPA, indicating that dietary 18-C fatty acids were to some extent converted into EPA in the juveniles. The catalase activity was significantly higher in groups S4, S5, S6 and S7 than that in other groups in the juveniles (P < 0.05). High catalase activity appeared in the sea cucumber juveniles when they grew fast, and superoxide dismutase had no apparent variations under different conditions.