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

Abstract:

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 16S 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.