To analyze the intestinal microbiota diversity of several important economic fishes in the Loudi area and its correlation with the microbiota of water environment, the high-throughput sequencing based on the bacteria 16S rRNA was used to analyze the intestinal microbiota diversity in fish intestines and water. The results revealed that half of the OTUs in the water sample could be detected in the fish intestine, the proportion of shared OTUs in the intestines of Hypophthalmichthys molitrix and water samples was only 22%, and the unique OTU in the LC group was relatively the highest in the fish intestinal group. It can be seen from the analysis in NMDS analysis, the distance between Hypophthalmichthys molitrix group and water group is relatively farthest. Ctenopharyngodon idellus has the highest microbiota richness and diversity (P < 0.05), while the water samples have the lowest microbiota richness (P < 0.05). Firmicutes, Methylocaldum and Bacillus are the prevalent taxonomic unit in the Aristichthys nobilis and Carassius auratus groups, Anaerospora is the prevalent genera in the Hypophthalmichthys molitrix group, Proteobacteria and Cyanobacteria have a high relative abundance ratio in the Ctenopharyngodon idellus group, and the prevalent taxonomic unit in the water sample group are Phenylobacterium, Bacteroidetes and Actinobacteria. In conclusion, fish species have different prevalent microbiota. There are a strong correlation between fish intestinal microbiota and the water environment, and the fish with a weak correlation is Hypophthalmichthys molitrix. Results of this study will contribute to the prevention and treatment of fish diseases and the fish ecological culturing in Loudi area.

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AimTo confirm the effects of Debaryomyces hansenii on intestinal microecology in mice with antibiotic-associated diarrhea (AAD).MethodsThis study took the mucosal microecology as the entry point and an antibiotic mixture was used to induce diarrhea in mice. D. hansenii suspension was used to treat the mice and the bacterial communities of mucosa was analyzed using high-throughput sequencing.ResultsThe Shannon-Wiener index indicated that the sequencing depth is reasonable and reflected the majority of microbial information. The principal coordinate analysis results showed that mice in the treatment group and the normal group had a similar microbial community structure, while differences in microbial community structure were observed between the model group and the treatment group. The inter-group bacterial structures were analyzed at the phylum level and genus level. The results revealed that antibiotic treatment increased the proportion of Proteobacteria and decreased the proportion of Bacteroides, while D. hansenii treatment inhibited the increase in Proteobacteria. Linear discriminant analysis coupled with effect size measurements (LEfSe) suggested d that the beneficial bacteria Candidatus Arthromitus were the only common bacteria in the normal group (P<0.05).ConclusionThe treatment with D.hansenii could contribute to the maintenance of the structure of the mucosal microbiota in comparison with the normal group and inhibit the proliferation of opportunistic bacteria. However, high-dose antibiotic treatment causes mucosal dysbiosis and the proliferation of opportunistic bacteria during the self-recovery period, such as Pseudoalteromonas, Alteromonas, Vibrio.

Adwmces in Biochemical Engineering/Biotechnology reviews actual trends in modern biotechnology. Its aim is to cover all aspects of this interdisciplinary technology where knowledge, methods and expertise are required for chemistry, biochemistry, microbiology, genetics, chemical engineering and computer science. Special volumes are dedicated to selected topics which focus on new biotechnological products and new processes for their synthesis and purification. They give the state-of-the-art of a topic in a comprehensive way thus being a valuable source for the next 3-5 years. It also discusses new discoveries and applications.In general, special volumes are edited by well known guest editors. The managing editor and publisher will however always be pleased to receive suggestions and supplementary information. Manuscripts are accepted in English.In references Advances in Biochemical Engineering/Biotechnology is abbreviated asAdv Biochem Engin/Biotechnol as a journal.