title: Parasitism perturbs the mucosal microbiome of Atlantic Salmon.
abstract: Interactions between parasite, host and host-associated microbiota are increasingly understood as important determinants of disease progression and morbidity. Salmon lice, including the parasitic copepod Lepeophtheirus salmonis and related species, are perhaps the most important problem facing Atlantic Salmon aquaculture after feed sustainability. Salmon lice parasitize the surface of the fish, feeding off mucus, scales and underlying tissue. Secondary bacterial infections are a major source of associated morbidity. In this study we tracked the diversity and composition of Salmo salar skin surface microbiota throughout a complete L. salmonis infection cycle among 800 post-smolts as compared to healthy controls. Among infected fish we observed a significant reduction in microbial richness (Chao1, P = 0.0136), raised diversity (Shannon, P < 7.86e-06) as well as highly significant destabilisation of microbial community composition (Pairwise Unifrac, beta-diversity, P < 1.86e-05; P = 0.0132) by comparison to controls. While undetectable on an individual level, network analysis of microbial taxa on infected fish revealed the association of multiple pathogenic genera (Vibrio, Flavobacterium, Tenacibaculum, Pseudomonas) with high louse burdens. We discuss our findings in the context of ecological theory and colonisation resistance, in addition to the role microbiota in driving primary and secondary pathology in the host.
authors.affiliation: School of Life Sciences, University of Glasgow, Glagsow, UK.
authors.forename: M S
authors.initials: MS
authors.lastname: Llewellyn
authors.affiliation: St Andrew's Marine Station, Department of Fisheries and Oceans, New Brunswick, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Leadbeater
authors.affiliation: Universite Laval, Quebec, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Garcia
authors.affiliation: Universite Laval, Quebec, Canada.
authors.forename: F-E
authors.initials: FE
authors.lastname: Sylvain
authors.affiliation: Universidade Federale do Rondonia, Porto Vehlo, Brazil.
authors.forename: M
authors.initials: M
authors.lastname: Custodio
authors.affiliation: Cooke Aquaculture, Canada.
authors.forename: K P
authors.initials: KP
authors.lastname: Ang
authors.affiliation: Cooke Aquaculture, Canada.
authors.forename: F
authors.initials: F
authors.lastname: Powell
authors.affiliation: Marine and Fisheries Genetics Laboratory, University of Wales, Bangor, Wales, UK.
authors.forename: G R
authors.initials: GR
authors.lastname: Carvalho
authors.affiliation: Marine and Fisheries Genetics Laboratory, University of Wales, Bangor, Wales, UK.
authors.forename: S
authors.initials: S
authors.lastname: Creer
authors.affiliation: Cooke Aquaculture, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Elliot
authors.affiliation: Universite Laval, Quebec, Canada.
authors.forename: N
authors.initials: N
authors.lastname: Derome
mesh_terms: D000818:Animals; D017756:Aquaculture; D033342:Copepoda / Q000472:pathogenicity* / Q000502:physiology; D005393:Fish Diseases / Q000382:microbiology / Q000469:parasitology*; D005417:Flavobacterium / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity; D014644:Genetic Variation; D006790:Host-Parasite Interactions; D054884:Host-Pathogen Interactions; D006801:Humans; D064307:Microbiota / Q000235:genetics; D009092:Mucous Membrane / Q000382:microbiology / Q000469:parasitology*; D011549:Pseudomonas / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity; D020317:Salmo salar / Q000382:microbiology / Q000469:parasitology*; D012867:Skin / Q000382:microbiology / Q000469:parasitology; D060493:Tenacibaculum / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity; D014733:Vibrio / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity