饲料脂肪水平对中间球海胆幼胆生长、消化酶和热胁迫后抗氧化酶活力的影响

为了确定中间球海胆Strongylocentrotus intermedius幼胆饲料中适宜的脂肪水平,采用摄食生长试验探讨了饲料中脂肪水平(3%、6%、9%、12%和15%)对海胆幼胆存活、生长、消化酶和热胁迫后抗氧化酶活力的影响,试验共进行96 d。结果表明:试验结束时,6%饲料脂肪水平组海胆增重率最高,显著高于15%脂肪组(P0.05);随着饲料脂肪水平的升高,中间球海胆消化道中脂肪酶活力显著升高(P0.05),淀粉酶活力显著下降(P0.05),胃蛋白酶活力有下降趋势(P0.05);饲料脂肪水平显著影响热胁迫后海胆体腔液中抗氧化酶活力,其中热胁迫2 h后,12%脂肪组超氧化物歧化酶(SOD)活力最高,显著高于15%脂肪组(P0.05);热胁迫6 h后,海胆体腔液过氧化氢酶(CAT)活力最高值出现在6%脂肪组,且高于12%和15%脂肪组。研究表明,6%饲料脂肪水平时中间球海胆幼胆的生长速率最快,6%~12%饲料脂肪水平能够显著提高热胁迫后海胆的抗氧化能力。

Effects of dietary lipid level on growth performance,digestive enzyme activity and anti-oxidative capacity after heat stress in juvenile sea urchin Strongylocentrotus intermedius

Juvenile sea urchin Strongylocentrotus intermedius were fed diets containing 3%, 6%, 9%, 12% and 15% of lipid for 96 days to investigate the effects of dietary lipid levels on growth performance, digestive enzyme activity and anti-oxidative capacity. Results showed that there was significantly higher or the maximal weight gain rate ( WGR) in the sea urchin fed the diet containing 3% lipid than that in the sea urchin fed the diet containing 15% lipid ( P<0. 05 ) . The amylase activity was shown to be significantly lower ( P<0. 05 ) and lower in pepsin in the sea urchin juveniles fed the elevated lipid diets. Lipase activity was increased significantly with the increase in dietary lipid (P<0. 05). Relatively high dietary lipid (6%-12%) led to improve activity of superoxide dismutase ( SOD) and anti-oxidant capacity ( AOC) in the thermal stress sea urchin, with the maximal SOD activity in the sea urchin exposed to 2 and 6 hour thermal stress in the 12% dietary lipid group, and significantly higher than that in the 15% dietary lipid group (P<0. 05). The maximal catalase (CAT) activity in coelomic fluid was observed in the sea urchin exposed to 15 min and 6 hour thermal stress in the 6% dietary lipid group, significantly higher than that in the 12% and 15% dietary lipid groups, and higher than that in the 15% dietary lipid group (P<0. 05), in-dicating that 6%-12% lipid was of the optimal for improvement of anti-oxidative capacity in response to thermal stress, though 6% lipid was suggested to be optimal for the growth of sea urchin.