饲料喷涂光合细菌对凡纳滨对虾肠道微生物多样性的影响

Effect of different photosynthetic bacteria coating diets on intestinal microbial diversity of white shrimp, Litopenaeus vannamei

以商品饲料为对照组(A组)、喷涂市售光合细菌菌液(B组)、红假单胞菌菌液(C组)和红螺菌菌液(D组)饲料为试验组,研究饲料喷涂不同光合细菌对凡纳滨对虾幼虾[(1.21±0.24) g]生长、肝胰腺消化酶活性及肠道微生物群落组成的影响。结果显示:光合细菌处理组(B、C和D组)的增重率高于对照组,但差异不显著(P>0.05);C组和D组对虾肝胰腺淀粉酶活力显著高于对照组(P<0.05);B、C和D组对虾肝胰腺脂肪酶活性均高于对照组(P<0.05),肝胰腺蛋白酶活性在各组间无显著性差异(P>0.05)。高通量测序结果表明,随着对虾的生长,其肠道微生物丰富度和多样性均提高。摄食喷涂光合细菌饲料后对虾肠道γ-变形细菌纲所占百分比减少,其中C组和D组γ-变形细菌纲比例显著低于对照组(P<0.05)。各组对虾肠道中检测到的占比大于0.5%的主要微生物属有9个,分别为希瓦氏菌属(Shewanella)、气单胞菌属(Aeromonas)、嗜冷菌属(Algoriphagus)、纤维弧菌属(Cellvibrio)、GpXIII、小梨形菌属(Pirellula)、浮霉状菌属(Planctomyces)、假单胞菌属(Pseudomonas)和红细菌属(Rhodobacter)。使用光合细菌没有显著改变对虾肠道微生物群落的整体丰富度和多样性,但在一定程度上丰富对虾肠道微生物属水平的组成。

In order to evaluate the effect of different dietary photosynthetic bacteria on growth,digestive enzymes and intestinal microbiota of white shrimp Litopenaeus vannamei,four diets(A:control diet;B:Commercial PSB coating diet;C:Rhodopeseudomonas coating diet;and D:Rhodospirillum coating diet)were fed to juvenile shrimp[(1.21±0.24)g]for 2 weeks,respectively.The results showed that:the weight gain rates of the photosynthetic bacteria treatment groups(B,C and D)were slightly higher than that of the control group without significant difference(P>0.05);the amylase activities in hepatopancreas of the shrimp in C and D treatments were significantly higher than that in A treatment(P<0.05);the lipase activities in hepatopancreas of the shrimp in B,C and D treatments were significantly higher than that in A treatment(P<0.05);and there was no significant difference in protease activity among the treatments(P>0.05).The results on sequencing the 16 S RNA genes of microbiota through high-throughput sequencing showed that the diversity and abundance of intestinal microbiota increased along with the shrimp growth.The shrimp fed diets coated with photosynthetic bacteria displayed a reduced proportion on intestinal Gammaproteobacteria accounting for intestinal microflora,the proportion on intestinal Gammaproteobacteria accounting for intestinal microflora of C and D treatments were significantly lower than that of control(P<0.05).Nine main genera(percentage>0.5%)intestinal microbiota,including Shewanella,Aeromonas,Algoriphagus,Cellvibrio,GpXⅢ,Pirellula,Planctomyces,Pseudomonas and Rhodobacter,coexisted in all the 4 treatments.It therefore suggests that the dietary photosynthetic bacteria application does not significantly alter the overall abundance and diversity of the intestinal microflora,but it enriches the genus composition of the main intestinal flora to a certain extent.