Gut Bacteria in Catfish and Carp: Healthy vs. Sick

Jim Crocker
16th March, 2024

Gut Bacteria in Catfish and Carp: Healthy vs. Sick

Image Source: Natural Science News, 2024

Key Findings

  • Study examined gut microbes in young and older striped pangasius catfish and catla during health and disease
  • Younger catfish had more Proteobacteria; older ones had more Firmicutes and Bacteroides
  • Findings may help develop new ways to protect fish from diseases in aquaculture
Understanding the complex world of gut microbiota—the myriad of microorganisms living in the digestive tracts of animals—has become a crucial part of modern aquaculture research. A healthy gut microbiome can protect fish from diseases, improve their growth, and even enhance their ability to utilize food. Disruptions to this delicate microbial ecosystem, however, can lead to disease and significant losses in fish farming. The recent study by the ICAR-Central Institute of Fisheries Education[1] delves into this intricate world, offering insights into how the gut microbiome of two types of fish—striped pangasius catfish and catla—changes during healthy and diseased states. The researchers collected intestinal samples from healthy fish and from fish that had been exposed to a lethal dose (LD50) of the bacterium Aeromonas hydrophila, a common pathogen in aquaculture that can cause severe infections. By using 16S metagenomic analysis, which is a method of identifying bacteria based on their genetic material, the team could compare the gut microbiota composition of these fish at different life stages and health conditions. The study found that the gut microbiome of fish varies not only with health status but also with their developmental stage. For instance, in the fingerling stage of pangasius catfish, the microbiome was dominated by Proteobacteria, a large group of microorganisms that include many pathogens. In contrast, advanced fingerlings had a higher presence of Firmicutes and Bacteroides, which are often associated with a healthy gut. The catla fish showed a predominance of Proteobacteria and Bacteroides across both healthy and diseased samples. These findings are significant because they suggest that the gut microbiome may shift naturally as fish grow, and that these shifts could influence their susceptibility to diseases. The dominance of Proteobacteria in younger fish could be a concern, as it includes many potential pathogens. However, understanding these changes can help in developing strategies to manage and manipulate the gut microbiome to improve fish health and disease resistance. The study's results also tie into previous research on the cell surface properties of intestinal bacteria in fish[2]. The ability of these bacteria to adhere to surfaces and form biofilms is critical for their survival and function within the host. The differences in microbial composition observed in the current study could be influenced by such properties, affecting how well these bacteria can colonize and protect the gut of fish at different life stages. Moreover, the study's findings echo the complex role that specific microbes like Akkermansia muciniphila play in the health of their hosts[3]. Although not explicitly mentioned in the study, the presence of beneficial microbes such as A. muciniphila, known for its positive effects on metabolism and gut health in other species, could also be influential in fish and is a potential area for further research. The impact of environmental stressors on gut microbiota, as seen in earlier studies where fish were exposed to pollutants and parasites[4], also highlights the resilience and adaptability of these microbial communities. While the current study focused on disease caused by a specific bacterium, it's clear that a multitude of factors, including environmental contaminants and parasites, can shape the gut microbiome. In conclusion, the research from the ICAR-Central Institute of Fisheries Education sheds light on the dynamic nature of the gut microbiome in fish and its implications for aquaculture. By understanding these microbial communities, we can better protect fish from diseases and improve their overall health, which is vital for the sustainability of fish farming. This study paves the way for the development of new, probiotic-based treatments that could bolster the natural disease resistance of fish, potentially reducing the need for antibiotics and other chemical treatments in aquaculture.

HealthGeneticsAnimal Science

References

Main Study

1) Comparative analysis of gut microbiome in Pangasionodon hypopthalmus and Labeo catla during health and disease.

Published 14th March, 2024

https://doi.org/10.1007/s10123-024-00494-x

Related Studies

2) Fish Probiotics: Cell Surface Properties of Fish Intestinal Lactobacilli and Escherichia coli.

https://doi.org/10.3390/microorganisms11030595

3) Akkermansia muciniphila as a Next-Generation Probiotic in Modulating Human Metabolic Homeostasis and Disease Progression: A Role Mediated by Gut-Liver-Brain Axes?

https://doi.org/10.3390/ijms24043900

4) Dysbiosis of fish gut microbiota is associated with helminths parasitism rather than exposure to PAHs at environmentally relevant concentrations.

https://doi.org/10.1038/s41598-022-15010-2


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