甘露寡糖对半滑舌鳎（Cynoglossus semilaevis Günther）稚鱼生长、肠道发育和非特异性免疫水平的影响

摘要

Mannan oligosaccharide (MOS) could promote the growth, intestinal development and non-specific immune index of some marine fishes; however, the role of MOS in the Cynoglossus semilaevis Günther postlarvae is unclear. The tongue sole postlarvae with initial length about 1.4 cm were fed Artemia, enriched by Schizochytrium with the addition (MOS group) or absence of MOS (control group) to study the effects of MOS on the growth, intestinal development and non-specific immunity. The experiments lasted for 34 days, and the samples were collected at day 17 and day 34. The results indicated that MOS significantly enhanced the body length at day 17 but it did not reach a significant effect at day 34. The MOS did not affect the growth and survival rate at both day 17 and day 34. MOS did not have a significant function on the ratios of RNA/DNA and protein/DNA at day 17 but it had a significant effect at day 34. MOS dramatically increased the amylase specific activity at day 17 and enhanced trypsin specific activity at day 34. At the end of the experiment, the superoxide dismutase, catalase, peroxidase and lysozyme activities in the MOS group were significantly higher than those of the control group (P<0.05), but the nitric oxide synthase activity was not significantly different (P>0.05) between the two groups. The microvilli length and the fold highness of the MOS group were significantly greater compared with the control group (P<0.05); the mucosal thickness between the two groups were not significantly different (P>0.05). These results indicated that MOS could improve the intestinal development and non-specific immunity of Cynoglossus semilaevis Günther postlarvae.%通过投喂经甘露寡糖强化的卤虫无节幼体，探索其对半滑舌鳎稚鱼(初始体长为1.4 cm左右)生长性能、肠道发育和非特异性免疫水平的影响。试验设两个处理组(对照组和甘露寡糖组)，分别投喂经裂壶藻或甘露寡糖+裂壶藻强化的卤虫无节幼体。试验进行34 d，每17 d取样1次。结果显示，17 d时甘露寡糖组体长显著大于对照组(P<0.05)。两组间的特定生长率和存活率无显著性差异(P>0.05)。RNA/DNA和protein/DNA的比值在17 d时两组间均无显著性差异(P>0.05)；34 d时甘露寡糖组的RNA/DNA和protein/DNA比值均大于对照组。甘露寡糖组17 d时淀粉酶比活力和34 d时胰蛋白酶比活力显著高于对照组(P<0.05)。甘露寡糖组的过氧化物歧化酶、过氧化氢酶、过氧化物酶和溶菌酶活性均显著高于对照组(P<0.05)。甘露寡糖组的微绒毛长度和皱襞高度显著大于对照组(P<0.05)；黏膜厚度大于对照组，但无显著性差异(P>0.05)。试验结果表明，甘露寡糖可以提高半滑舌鳎稚鱼肠道发育和非特异性免疫水平。