Does aquaculture turn your stomach? Fish too!

This study focuses on the intestinal microbiota of the fine flounder (Paralichtys adspersus), a flatfish of commercial interest that is native to the Chilean coast. Intestinal microbiota is involved in a wide range of internal processes, such as modulating the immune system and providing nutrition. The societal value of the fine flounder has encouraged the development of aquaculture activities and stock enhancement, making it a species of interest when exploring . Knowledge of microbiota may aid in improving the cultivation of this species and so this study aimed to evaluate the intestinal microbiota community in farmed versus wild fishes.

Contents from the intestines of wild and reared fish were collected and DNA was extracted and then the V3-region of 16S rRNA was PCR amplified and sequenced using the Ion Torrent platform. The compositions of microbiota found in each group of specimens showed important distinctions between reared fish and wild fish. In wild flounder, the most abundant phylum was Proteobacteria which was found in far lower abundances in the reared flounder. Contrastingly, in the reared flounder, the most abundant phylum was Firmicutes, which was much less common in the wild flounder.

A total of four genera were identified between the two conditions and Bacillus and Pseudomonas being highly represented in the reared flounder and Athrobacter and Psychrobacter being highly represented in the wild flounder. These results show that, though in both cases, metabolic pathways indicated that the microbiota compositions found would have beneficial effects for the host, but wild flounder showed more remarkable pathways.

I personally found this paper to be very interesting, perhaps because it feels very current and important. There are mixed opinions on various aspects of aquaculture, such as the ethical treatment of livestock and thus the quality of the product, and the implications to the immediate and extended environment. This paper is one of the only studies I have come across where the actual individual organisms are assessed for the impact of aquaculture rather than looking at the bigger picture, showing that the effects of this type of agricultural practice has impacts on all scales. The only criticism I have is that it tends to get a little repetitive in parts. 

Reference: Ramírez, C. and Romero, J. (2017). Fine Flounder (Paralichthys adspersus) Microbiome Showed Important Differences between Wild and Reared Specimens. Frontiers in Microbiology, 08.