Information on the gut microbiome composition of different mammals could provide novel insights into the evolution of mammals and succession of microbial communities in different hosts. However, there is limited information on the gut microbiome composition of marine mammals, especially cetaceans because of sampling constraints. In this study, we investigated the diversity and composition of microbial communities in the stomach, midgut, and hindgut of 2 stranded short‐finned pilot whales (Globicephala macrorhynchus) and hindgut of a stranded pygmy sperm whale (Kogia breviceps) by using 16S rRNA gene amplicon sequencing technology. On the basis of the 50 most abundant operational taxonomic units, principal coordinate analysis, and non‐metric multidimensional scaling analysis, we confirmed that the gut microbial communities of the 3 whales were different. Our results revealed that the gut microbiome of 1 stranded short‐finned pilot whale GM16 was dominated by Firmicutes (mainly Clostridium) and Fusobacteria; whereas that of the other pilot whale GM19 was composed of Gammaproteobacteria and Bacteroidetes (mainly Vibrio and Bacteroides, respectively), probably caused by intestinal disease and antibiotic treatment. The gut microbiome of the pygmy sperm whale was dominated by Firmicutes and Bacteroidetes. Moreover, different gastrointestinal tract regions harbored different microbial community structures. To our knowledge, this is the first report of the gut microbiome of short‐finned pilot whales, and our findings will expand our current knowledge on microbial diversity and composition in the gastrointestinal tract of cetaceans.

中文翻译：

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两条搁浅的短鳍领航鲸 (Globicephala macrorhynchus) 和一头侏儒抹香鲸 (Kogia breviceps) 的胃肠道微生物多样性和结构

关于不同哺乳动物肠道微生物组组成的信息可以为哺乳动物的进化和不同宿主中微生物群落的演替提供新的见解。然而，由于采样限制，关于海洋哺乳动物，尤其是鲸类的肠道微生物组组成的信息有限。在这项研究中，我们调查了 2 条搁浅的短鳍领航鲸 ( Globicephala macrorhynchus ) 和搁浅的抹香鲸 ( Kogia breviceps )的胃、中肠和后肠中微生物群落的多样性和组成。) 通过使用 16S rRNA 基因扩增子测序技术。基于 50 个最丰富的操作分类单元、主坐标分析和非度量多维尺度分析，我们确认 3 头鲸鱼的肠道微生物群落不同。我们的研究结果表明，1 条搁浅的短鳍领航鲸 GM16 的肠道微生物群以厚壁菌门（主要是梭菌）和梭杆菌门为主；而另一头领航鲸 GM19 则由 Gammaproteobacteria 和 Bacteroidetes 组成（主要是Vibrio和Bacteroides，分别），可能是由肠道疾病和抗生素治疗引起的。侏儒抹香鲸的肠道微生物群以厚壁菌门和拟杆菌门为主。此外，不同的胃肠道区域具有不同的微生物群落结构。据我们所知，这是关于短鳍领航鲸肠道微生物组的第一份报告，我们的研究结果将扩展我们目前对鲸目动物胃肠道微生物多样性和组成的了解。