饲料中花生四烯酸对中间球海胆存活、生长和肠道菌群组成的影响

Effects of dietary arachidonic acid on survival and growth performance and the intestinal bacterial profile of adult sea urchin( Strongylocentrotus intermedius)

以中间球海胆(Strongylocentrotus intermedius)为研究对象,探讨饲料中不同水平(0.0、0.5%、1.0%和2.0%饲料干物质)的花生四烯酸(arachidonic acid,ARA)对其存活、生长和肠道菌群组成的影响。饲料中添加或不添加ARA饲喂56 d后统计12个网笼海胆的存活数量及体重变化,随后每个网笼随机选取10只海胆,无菌收集肠道内容物进行高通量测序分析肠道菌群组成。结果表明:饲料中不同含量水平的ARA对海胆的成活率无显著影响(P>0.05),但随着饲料中ARA添加量的升高,海胆的增重率先升后降。当饲料中添加1.0%ARA时,海胆增重率最高,且显著高于空白组和0.5%添加组(P<0.05),但与2.0%添加组差异不显著(P>0.05)。高通测序发现:肠道菌群的多样性和门水平的丰度差异不显著(P>0.05),但属水平的丰度差异显著(P<0.05)。各饲料处理组海胆肠道中变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)和厚壁菌门(Firmicutes)的丰度均较高;随着饲料中ARA水平的升高,海胆肠道中变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)有升高的趋势(P>0.05),弧菌属(Vibrio)和(Lutibacter)的丰度显著升高(P<0.05);而厚壁菌门(Firmicutes)和软壁菌门(Tenericutes)则下降,但不显著(P>0.05);芽孢杆菌属(Bacillus)和(Candidatus Hepatoplasma)的丰度显著降低(P<0.05)。因此,尽管饲料中添加ARA不影响中间球海胆的成活率,但饲料中添加1.0%~2.0%ARA较低添加量能够显著提高海胆的生长速率,且添加不同水平的ARA均显著影响了海胆肠道菌群组成,这不仅有助于明确ARA添加对中间球海胆存活、生长和肠道菌群组成的影响,也为开发适合海胆的微生态制剂提供了理论依据。

This study focused on sea urchins（ Strongylocentrotus intermedius） and the effects of different graded level of arachidonic acid（ ARA）（ 0,0. 5%,1. 0% and 2. 0% dry diet） in the feed on their survival rate（ SR）,weight gain rate（ WGR） and intestinal bacterial profile. 12 cages of urchins were calculated SR and WSR with or without graded level of ARA for 56 days. 10 urchins were randomly selected from each cage,and intestinal contents were aseptically collected using high-throughput sequencing technology to analyze bacterial profile. The results showed that graded level of ARA in diet had no significant effect on the SR of urchins（ P 0. 05）,but with the increase of ARA in feed,their WGR were first increased and then decreased. Among all the graded level of ARA,WGR of urchins was the highest when the content of ARA administration was 1. 0% compared with those of other groups（ P 0. 05）.High-throughput sequencing analysis revealed that there was no significant difference in the diversity of intestinal bacterial profile and the abundance of phylum levels（ P 0. 05）,but abundance of genus levels were showed a significant difference（ P 0. 05）. The richness of Proteobacteria,Bacteroidetes and Firmicutes in the intestinal tract were relative higher compared with other phylum; with the increase of ARA levels in feed,an upward trend was observed on richness of Proteobacteria and Bacteroidetes in urchins（ P 0. 05）. The richness of Vibrio and Lutibacter were significantly increased（ P 0. 05）,while those of Firmicutes and Tenericutes were decreased（ P 0. 05）; the abundance of Bacillus and（ Candidatus Hepatoplasma） decreased significantly（ P 0. 05）. Therefore,SR of urchins did not markedly change after the addition of ARA,but the addition of 1. 0%-2. 0% ARA could significantly increase WGR of urchins,and addition of ARA significantly could rich the abundance of Proteobacteria and Bacteroidetes.Based on these,the clarification of ARA addition on the SR,WGR,and intestinal bacterial profile of urchins might be benefit for the development of suitable microecological preparations for them.