Association of microbial community structure with gill disease in marine-stage farmed Atlantic salmon (Salmo salar); a yearlong study

• Published in: BMC Veterinary Research
• Main Authors: Morag Clinton, Adam J. Wyness, Samuel A. M. Martin, Andrew S. Brierley, David E. K. Ferrier
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2024
• Subjects: Fish health; Gill microbiome; Atlantic salmon aquaculture; Gill pathology; Pathobiome; Dysbiosis; Veterinary medicine; SF600-1100; Atlantic salmon; Salmo salar
• Online Access: https://doi.org/10.1186/s12917-024-04125-5; https://doaj.org/article/6b6ef8664f9147daaa8fe9005a4922df

Abstract Background Understanding the relationship between resident microbiota and disease in cultured fish represents an important and emerging area of study. Marine gill disorders in particular are considered an important challenge to Atlantic salmon (Salmo salar) aquaculture, however relatively little is known regarding the role resident gill microbiota might play in providing protection from or potentiating different gill diseases. Here, 16S rRNA sequencing was used to examine the gill microbiome alongside fish health screening in farmed Atlantic salmon. Results were used to explore the relationship between microbial communities and gill disease. Results Microbial community restructuring was observed throughout the sampling period and linked to varied drivers of change, including environmental conditions and severity of gill pathology. Taxa with significantly greater relative abundance on healthier gills included isolates within genus Shewanella, and taxa within family Procabacteriaceae. In contrast, altered abundance of Candidatus Branchiomonas and Rubritalea spp. were associated with damaged gills. Interestingly, more general changes in community richness and diversity were not associated with altered gill health, and thus not apparently deleterious to fish. Gross and histological gill scoring demonstrated seasonal shifts in gill pathology, with increased severity of gill damage in autumn. Specific infectious causes that contributed to observed pathology within the population included the gill disorder amoebic gill disease (AGD), however due to the uncontrolled nature of this study and likely mixed contribution of various causes of gill disease to observed pathology results do not strongly support an association between the microbial community and specific infectious or non-infectious drivers of gill pathology. Conclusions Results suggest that the microbial community of farmed Atlantic salmon gills undergo continual restructuring in the marine environment, with mixed influences upon this change including ...