饲料中添加壳寡糖对刺参肠壁菌群的影响

为研究饲料中添加壳寡糖对刺参Apostichopus japonicus肠壁菌群的影响,在刺参基础饲料中分别添加0.25%(G1)、0.50%(G2)、0.75%(G3)和1.00%(G4)的壳寡糖,另设对照组(G0),养殖50 d后采集各组刺参幼参(5.03 g±0.03 g)肠壁样品,并采用高通量测序技术分析刺参肠壁菌群结构特征。结果表明:壳寡糖添加组刺参肠壁的细菌多样性和丰度均高于对照组;各组样品肠壁优势菌门均为变形菌门和厚壁菌门;壳寡糖对刺参肠壁菌群组成产生了明显影响,对照组优势菌属为希瓦氏菌属Shewanella,而壳寡糖添加组希瓦氏菌属的相对比例均下降,对照组芽孢杆菌属Bacillus的相对比例较低,而壳寡糖添加组芽孢杆菌属的相对比例均较高或成为优势菌属;1.00%壳寡糖组各类菌属相对比例均较低,高浓度壳寡糖出现抑制现象。研究表明,饲料中添加壳寡糖可提高刺参肠壁细菌多样性和丰度,明显改善刺参肠壁菌群结构。

Effect of dietary chitosan oligosaccharide on bacterial community in intestinal wall of sea cucumber Apostichopus japonicus

The bacterial community in intestinal wall was investigated in sea cucumber Apostichopus japonicus(5. 03 g±0. 03 g) fed diets containing chitosan oligosaccharide(COS) at dose of 0(G0,as control group), 0. 25% (G1), 0. 50% (G2), 0. 75% (G3) and 1. 00% (G4) for 50 days by high-through sequencing technique in order to e-valuate the effect of dietary COS on the bacterial community structures. The results showed that there were higher bacterial diversity and abundance in the intestinal wall of the sea cucumber fed the diets containing COS than the sea cucumber fed the control diet, with dominant Proteobacteria and Firmicutes, indicating that composition of in-testinal bacteria was affected by COS. The dominant genus Shewanella was observed in the intestinal wall of the sea cucumber in the control group, while the proportion of Shewanella was found to be reduced in the intestinal wall of the sea cucumber fed the diets containing COS. It was found that Bacillus was increased in amount even became the dominant bacteria in the intestinal wall of the sea cucumber fed the diets containing COS compared with the sea cu-cumber fed the control diet. In group G4, however, there was lower relative proportion of various bacterial genera, high dose of COS showing inhibitory effect of bacterial diversity. The findings suggest that only optimal dose of diet-ary COS improve bacterial diversity and abundance in the intestinal wall of the sea cucumber.