The Effects Of Enzymatic Hydrolysates Of Sea Cucumber Gonads On Intestinal Microbiota Of Iaboratory Animals

The gonads of sea cucumber contains a variety of active substances,such as polysaccharide,polypeptide and saponins and so on.All of these were important active substances for the human body.Intestinal microorganisms were an important part of the host.Studies have shown that the intake of polysaccharides would help to improve and regulate the relationship between the intestinal microbes and the host.In this study,experimental animals were fed with sea cucumber gonad enzymolysis products.Total microbial DNA was extracted from feces and intestinal tract of experimental animals.The dynamic changes of intestinal microflora in experimental animals were analyzed using DGGE and Illumina Miseq sequencing technologies.From the point of view of gut microbiota,we studied the effects of sea cucumber gonad enzymolysis products(mainly polysaccharides and peptides)on the host.The results were as follows:1.PCR-DGGE and Illumina Miseq sequencing were used to study the effects of enzymatic hydrolysates of sea cucumber gonads on the microbial community structure and dynamic changes in mouse feces.The results indicated that:(1)At the phylum level,Bacteroidetes was the predominant group in mouse feces.Proteobacteria were the subdominant bacterial group.In the ceca of mice,the dominant bacteria group was Firmicutes.Bacteroidetes was the second dominant group.At the genus level,many unclassified and uncultured bacterial clones were detected in mouse feces.In the ceca of mice,norank_f_S24-7 was the dominant genus.The norank_f__Lachnospiraceae and the Blautia were the subdominant.(2)Feeding with sea cucumber gonad hydrolysates increased the microbial diversity index in the feces and ceca of mice.The DGGE clustering and Beta diversity analysis showed that,the administration of sea cucumber gonad enzymolysis products had a significant effect on the bacterial composition in feces and ceca of mice.(3)Feeding with sea cucumber gonad enzymolysis products increased the abundance of Bacteroidetes and Candidate_division_TM7 in the ceca of mice and reduced the abundance of Firmicutes.medium-dose treatment increased the abundance of δ-Proteobacteria.Compared with the control,the relative abundance of the following genera increased in the sea cucumber gonad hydrolysates feeding group: Parabacteroides and Ruminococcus etc.On the contrary,compared with the control,the abundance decreased genera were: Mucispirillum etc.2.Illumina Miseq sequencing was used to study the effects of sea cucumber flower hydrolysate on intestinal microbial community structure of tilapia.The results showed:(1)At the phylum level,the dominant bacterial groups were Fusobacteria and Proteobacteria(γ-,α-,β-,and δ-proteobacteria).At the genus level,Cetobacterium was the dominant genus in most tilapia intestine samples.In the aquaculture water,Bacteroidetes was the dominant phylum,and Proteobacteria was the subdominant phylum.At the genus level,Flectobacillus is the dominant genus.(2)Feeding with sea cucumber gonad hydrolysate increased the specific growth rate and weight gain rate of tilapia.In addition,the diversity index of tilapia intestine samples increased.Clustering analysis indicated that sea cucumber gonad enzymolysis products had significant effects on the composition of tilapia gut microbiota at phylum,genus and OTU levels.(3)sea cucumber gonad hydrolysates increased the abundance of Proteobacteria,Microcystis,and Chlamydia in the intestine of tilapia.Reduces the abundance of Bacteroidetes,Fusobacteriaceae,and actinomycetes.At the genus level,the relative abundances of the genera Aeromonas,Enterobacter,Rhizobium,and Cetobacterium increased in abundance compared to the control group were Pseudomonas and Vogesella.