水解单宁对凡纳滨对虾生长性能和肠道微生物的影响

为分析水解单宁对凡纳滨对虾生长及其肠道微生物菌群结构的影响,以基础饲料为空白组,在基础饲料中分别添加0.1%、0.2%和0.3%的水解单宁作为实验组,进行为期60 d的养殖实验后,统计生长性能,并取其肠道内容物提取DNA,用Illumina MiSeq测序平台进行16S rDNA基因V3～V4区高通量测序,检测对虾肠道内菌群结构及变化情况。结果表明:(1) 3个水解单宁添加组的增重率、特定生长率和肥满度与对照组相比均显著升高(P0.05),肝体比均显著降低(P0.05)。(2)4组样品中共获得206192条优化序列,操作分类单元(OUT)总数达542个。对照组凡纳滨对虾肠道微生物以变形菌门和蓝细菌门为主,其次是放线菌门和拟杆菌门;试验组肠道主要菌群为变形菌门、软壁菌门。试验组与对照组相比,蓝细菌门、放线菌门和拟杆菌门的比例降低,变形菌门、软壁菌门和厚壁菌门比例增加。(3)Rank-Abundance曲线和多样性指数结果可见,实验组的物种丰度和均匀度大体上均高于对照组。PCoA分析发现, 0.1%和0.3%添加组的微生物群落较为接近,而与0.2%添加组差别较大,结合生长性能指标可知,饲料中水解单宁的最适添加量为0.1%。以上研究表明,饲料添加水解单宁可显著改变对虾肠道的微生物组成,提高对虾生长速度,影响凡纳滨对虾的生长性能。

Effects of hydrolyzable tannins on growth performance and intestinal microflora in Litopenaeus vannamei

To study the effect of hydrolyzable tannins (HT) on the growth performance and intestinal microflora of Litopenaeus vannamei, HT was added to basic feed at concentrations of 0.1%, 0.2%, and 0.3%. After a 60-day feeding test, the growth performance of L. vannamei was determined and high-throughput sequencing was used to analyze the composition and variation of gut microbiota. The results showed that:(1) the rate of weight gain, specific growth rate, and condition factor of three experimental groups were significantly higher than those of the control group (P<0.05), whereas the hepatosomatic indices were significantly lower (P<0.05). (2) In total, 206192 optimized sequences were obtained from the four samples, with 542 operational taxonomic units. The intestinal microflora of L. vannamei in the control group contained a high proportion of Proteobacteria and Cyanobacteria, followed by Actinobacteria and Bacteroidetes. The dominant phyla in the experimental groups were Proteobacteria and Tenericutes. Compared to the control group, the proportion of Cyanobacteria, Actinobacteria, and Bacteroidetes decreased, whereas the proportion of Proteobacteria, Tenericutes, and Firmicutes increased in the experimental groups. (3) Rank-abundance curve and diversity analysis revealed that the species abundance and species evenness were higher in the experimental groups than in the control group. PCoA analysis showed that the microbial communities in the 0.2% and 0.3% groups were similar, but significantly different from those of the 0.1% group. Combined with growth performance indicators, we concluded that adding 0.1% HT to the diet might be most economical. In conclusion, dietary HT could significantly affect the intestinal microflora of L. vannamei and enhance its growth performance.