title: Pseudomonas M162 confers protection against rainbow trout fry syndrome by stimulating immunity.
abstract: OBJECTIVE
  To evaluate the antagonistic effect of Pseudomonas M162 against Flavobacterium psychrophilum.
  
  
  RESULTS
  The antagonistic activity of M162 was tested in vivo and in vitro, and its mode of action examined by siderophore production and immunological responses of rainbow trout (Oncorhynchus mykiss) fry. Pseudomonas M162 inhibited the growth of Fl. psychrophilum in vitro and increased the resistance of the fish against the pathogen, resulting in a relative per cent survival (RPS) of 39·2%. However, the siderophores produced by M162 did not have an inhibitory effect on Fl. psychrophilum. In fish fed with M162, the probiotic colonized the gastrointestinal tract and stimulated peripheral blood leucocyte counts, serum lysozyme activity and total serum immunoglobulin levels after 3 weeks from the start of feeding.
  
  
  CONCLUSIONS
  This study showed the potential of Pseudomonas M162 as a probiotic by reducing the mortalities that occurred during an experimental Fl. psychrophilum infection, resulting mainly through the immunostimulatory effects of the bacterium.
  
  
  CONCLUSIONS
  Rainbow trout fry syndrome (RTFS) causes high mortalities during the early life stages of the fish's life cycle, partly because their adaptive immunity has not yet fully developed. Thus, immunomodulation by probiotics could be an effective prophylactic method against RTFS.
authors.affiliation: Institute of Aquaculture, University of Stirling, Stirling, UK. tiina.korkea-aho@evira.fi
authors.forename: T L
authors.initials: TL
authors.lastname: Korkea-aho
authors.forename: A
authors.initials: A
authors.lastname: Papadopoulou
authors.forename: J
authors.initials: J
authors.lastname: Heikkinen
authors.forename: A
authors.initials: A
authors.lastname: von Wright
authors.forename: A
authors.initials: A
authors.lastname: Adams
authors.forename: B
authors.initials: B
authors.lastname: Austin
authors.forename: K D
authors.initials: KD
authors.lastname: Thompson
mesh_terms: D000821:Animal Feed; D000818:Animals; D000898:Antibiosis; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology; D005393:Fish Diseases / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control; D045826:Flavobacteriaceae Infections / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D005417:Flavobacterium / Q000254:growth & development / Q000276:immunology / Q000472:pathogenicity*; D056724:Immunity, Humoral; D007113:Immunity, Innate; D007075:Immunoglobulin M / Q000097:blood / Q000276:immunology; D056747:Immunomodulation; D007422:Intestines / Q000382:microbiology; D017686:Oncorhynchus mykiss / Q000276:immunology* / Q000382:microbiology; D019936:Probiotics / Q000008:administration & dosage; D011549:Pseudomonas / Q000276:immunology*; D017262:Siderophores / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D007075:Immunoglobulin M; D017262:Siderophores