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Both fish gills and guts can support lots of microbiota that play important roles in the health and growth of hosts. Although the microbiota of silver carp has been widely studied, the data on microbial variation according to fish tissues and local habitats are lacking. In this study, the microbes in the guts and gills of silver carp (Hypophthalmichthys molitrix) from the hydrophyte-dominated region (zone H) and the algae-dominated region (zone A) of Taihu Lake in autumn were analyzed. Proteobacteria, Cyanobacteria, and Firmicutes were the dominant bacteria in silver carp. The microbial diversity was higher in the gills than that in the intestines, and higher in fish from zone H than that from zone A. Beta diversity analysis revealed significant differences in microbial community structures between gill and guts, and between fish from the two habitats. Gills had a higher abundance of phyla Actinobacteria, Bacteroidetes, and Deinococcus-Thermus, and a lower abundance of verrucomicrobia than the intestine. Both tissues possessed indicator taxa, while many indicator taxa in the gill were conditional pathogens. Compared to fish from zone H, fish from zone A had more abundant Cyanobacteria, and less abundant Proteobacteria and Bacteroidetes. PICRUSt2 analysis revealed that fish microbial functions were mainly associated with metabolism, replication, repair, folding, sorting, and degradation. These results showed that the microbial community of silver carp from Taihu Lake varied according to tissues and habitats.

The Yangtze finless porpoise (Neophocaena asiaeorientalis) is the sole freshwater subspecies of Neophocaenaphocaenoides, and there is a lack of data on its transcriptome. In this study, we applied RNA-seq technology to assemble, de novo, a transcriptome and analyzed differential expressed genes (DEGs). About 6 Gb of clean data was generated for the Yangtze finless porpoise blood (n = 6) through de novo sequencing. In total, 151,211 unigenes were generated and a total of 119,039 of these unigenes (78.72%) were functionally annotated when searched for within the NCBI Nr, SwissProt, GO, COG, and KEGG databases. Diverse and extensive expressed gene catalogs were sampled for the Yangtze finless porpoise. DESeq2 was used to analyze the differential expression genes (DEGs) obtained from the assembled transcriptome. The results indicated that DEGs have close relationships with the Yangtze finless porpoise’s development, evolution and adaptation. Further, we found that genes involved in cetacean TAG synthesis might directly explain the molecular basis of cetacean blubber thickening. These transcriptome data will assist in understanding molecular mechanisms of Yangtze finless porpoise adaptation.