A groundbreaking study published in the journal Fish and Shellfish Immunology has accentuated the significance of gut microorganisms and their metabolic byproducts in safeguarding the intestinal health of crustaceans on high-fat diets. Researchers from China have meticulously unravelled the physiological intricacies behind the barrier damage experienced by Macrobrachium rosenbergii when subjected to excessive fat intake, offering unprecedented insights into the nuanced interplay between diet and aquatic health.

High-Fat Diets and Crustacean Health

The study, with DOI: [10.1016/j.fsi.2024.109376], led by Xiaochuan Zheng and a team of scientists, employed phenotypic characterizations, cutting-edge 16S rDNA sequencing, and targeted metabolomics to establish a high-fat diet-induced intestinal barrier damage model in the species known commonly as the giant freshwater prawn. Over an 8-week period, the researchers observed significant degradation in the integrity of intestinal epithelial cells, tight junction structures, and permeability upon high-fat diet administration.

The Role of Gut Microbiota and Metabolic Products

Findings revealed that a high-fat diet instigated notable alterations in the gut microbiota composition. Specifically, a surge in the abundance of pathogen-related genera such as Aeromonas, Enterobacter, and Clostridium sensu stricto 3 was observed. Conversely, beneficial bacteria including Lactobacillus, Lactococcus, Bacteroides, and Ruminococcaceae UCG-010 saw a significant decline in numbers.

Crucially, metabolic products such as bile acids and short-chain fatty acids, which are pivotal for gut health, displayed marked disruptions. An increase in the presence of deoxycholic acid (DCA), 12-ketolithocholic acid (12-KetoLCA), 7,12-diketolithocholic acid (7,12-diketoLCA), and isovaleric acid was noted, alongside a noteworthy reduction in hyodeoxycholic acid (HDCA), chenodeoxycholic acid (CDCA), and acetate in the high-fat diet group.

Implications for Intestinal Barrier Function

The study’s Pearson correlation analysis elucidated a strong correlation between specific genera (Clostridium sensu stricto 3, Lactobacillus, Bacteroides) and the secondary metabolites mentioned, with a significant correlation also found between these metabolites and genes related to intestinal barrier function (Relish, ZO-1, MLCK, vitamin D receptor, and ecdysone receptor).

The disconcerting effects of high-fat intake were multifaceted, bringing to light not only the damage to the intestinal barrier but also the evident dysbiosis in the gut microbiota. This disturbance in the microbial equilibrium flagged the pressing need for precise dietary regulations and interventions in crustacean nutrition.

The research emphasizes the importance of microorganisms inhabiting the gut and their biochemical products in modulating the adverse outcomes of high-fat diets on *M. rosenbergii*. Through targeted microbiota and metabolite manipulation, the aquaculture industry may soon be able to forge innovative nutritional strategies that could underpin the wellbeing of crustaceans and, by extension, the sustainability of aquaculture practices.

Pioneering Research Spearheaded by Authorities in Aquatic Health

Led by the tenacious efforts of researchers at the Freshwater Fisheries Research Center (FFRC) of the Chinese Academy of Fishery Sciences (CAFS), Wuxi Fisheries College of Nanjing Agricultural University, and the Key Laboratory of Fish Health and Nutrition of Zhejiang Province, their collective findings present a significant stride in aquatic animal research.

The study authors – Xiaochuan Zheng, Xiaodi Xu, Mingyang Liu, Jie Yang, Meng Yuan, Cunxin Sun, Qunlan Zhou, and Jianming Chen – harnessed their collective expertise to navigate the complex nexus between dietary factors and immunobiology in crustaceans.

Transforming Aquaculture Practices and Dietary Guidelines

This research advocates for a paradigm shift in how high-fat diets are approached in commercial aquaculture, underscoring how tailored feeding practices that consider the optimal balance of lipids could promote intestinal health and enhance disease resistance in economically important crustacean species.

The study has ushered in a clarion call for additional research to further decipher the molecular mechanisms governing the gut microbiota’s response to diet alterations. The identification and targeting of key microbial players and metabolites may serve as robust biomarkers for nutritional status and health in crustaceans, solidifying the foundation for precision nutrition in aquaculture.

Future Outlook and Recommendations

As the global aquaculture industry strives to meet the rising demand for seafood sustainably, the findings from this study remind stakeholders of the pivotal role played by gut health in the productivity and welfare of aquatic livestock. Continuous advancements in our understanding of dietary effects on the microbiome stand to revolutionize the sector, ensuring both the economic viability of aquaculture operations and the protection of aquatic species.

Researchers recommend that forthcoming studies should delve into the therapeutic potentials of probiotics, prebiotics, and other gut health enhancers in mitigating the implications of high-fat diets, and how these strategies might be harnessed to reinforce the resilience of crustaceans against environmental and dietary stresses.

Keywords

1. Crustacean intestinal health
2. High-fat diet crustaceans
3. Gut microbiota aquaculture
4. Macrobrachium rosenbergii nutrition
5. Aquatic animal dietary management

References

1. Zheng, X., Xu, X., Liu, M., et al. (2024). Bile acid and short chain fatty acid metabolism of gut microbiota mediate high-fat diet induced intestinal barrier damage in Macrobrachium rosenbergii. Fish & Shellfish Immunology, 146, 109376. [https://doi.org/10.1016/j.fsi.2024.109376](https://doi.org/10.1016/j.fsi.2024.109376)
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