title: Effectiveness of egg yolk immunoglobulin against the intracellular salmonid pathogen Piscirickettsia salmonis.
abstract: OBJECTIVE
  To produce and characterize egg yolk immunoglobulin (IgY) against the fish intracellular pathogen Piscirickettsia salmonis as well as to evaluate the antibacterial activity of IgY in vitro and the availability in the serum of fish immunized orally.
  
  
  RESULTS
  Specific IgY was produced by immunizing hens with P. salmonis proteins. The IgY was obtained from egg yolks using the ammonium sulphate precipitation method and it was characterized by SDS-PAGE, Western-blot and ELISA, demonstrating that anti-P. salmonis IgY strongly reacted specifically against P. salmonis proteins. In an in vitro neutralization assay, IgY inhibited the growth of P. salmonis in liquid medium at concentrations ranging from 128 to 256 μg ml(-1) in a dose-dependent manner. Interestingly, IgY against P. salmonis also generates a strong protective effect on the infection of P. salmonis in salmon head kidney-1 cells. In addition, the bacteriostatic function of IgY appears to result possibly from agglutination by the interaction of IgY with surface components of the pathogen. Finally, to confirm this IgY as an alternative for salmonid treatment, Atlantic salmon (Salmo salar) specimens were orally inoculated with IgY. The analysis of the sera demonstrates that IgY was effectively transported by fish intestine and that this immunoglobulins maintains its properties and recognizes several proteins of P. salmonis up to 12 h after inoculation of IgY against P. salmonis.
  
  
  CONCLUSIONS
  Specific IgY effectively inhibited the growth of P. salmonis and this immunoglobulin can be released in the Atlantic salmon sera when administered orally to fish.
  
  
  CONCLUSIONS
  We propose that this specific IgY against this fastidious micro-organism could be a useful strategy for the treatment of piscirickettsiosis.
authors.affiliation: Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.
authors.forename: C
authors.initials: C
authors.lastname: Oliver
authors.affiliation: Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.
authors.forename: K
authors.initials: K
authors.lastname: Valenzuela
authors.affiliation: Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.
authors.forename: H
authors.initials: H
authors.lastname: Silva
authors.affiliation: Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.
authors.forename: R E
authors.initials: RE
authors.lastname: Haro
authors.affiliation: Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.
authors.forename: M
authors.initials: M
authors.lastname: Cortés
authors.affiliation: Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.
authors.forename: R
authors.initials: R
authors.lastname: Sandoval
authors.affiliation: Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.
authors.forename: J P
authors.initials: JP
authors.lastname: Pontigo
authors.affiliation: Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.
authors.forename: C
authors.initials: C
authors.lastname: Álvarez
authors.affiliation: Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.|Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile.
authors.forename: J E
authors.initials: JE
authors.lastname: Figueroa
authors.affiliation: Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile.|Laboratorio de Patología de Organismos Acuáticos y Biotecnología Acuícola, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Viña del Mar, Chile.|Centro de Investigación Marina Quintay (CIMARQ), Quintay, Chile.
authors.forename: R
authors.initials: R
authors.lastname: Avendaño-Herrera
authors.affiliation: EWOS Innovation Chile, Calbuco, Chile.
authors.forename: J M
authors.initials: JM
authors.lastname: Troncoso
authors.affiliation: Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.|Interdisciplinary Center for Aquaculture Research (INCAR), Concepción, Chile.
authors.forename: A J
authors.initials: AJ
authors.lastname: Yáñez
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D002645:Chickens / Q000276:immunology; D004530:Egg Yolk / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D005393:Fish Diseases / Q000188:drug therapy / Q000276:immunology / Q000382:microbiology*; D007136:Immunoglobulins / Q000302:isolation & purification / Q000494:pharmacology*; D053522:Piscirickettsia / Q000187:drug effects* / Q000254:growth & development; D044225:Piscirickettsiaceae Infections / Q000188:drug therapy / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D020317:Salmo salar / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; C016512:IgY; D007136:Immunoglobulins
keywords: IgY; Piscirickettsia salmonis; chicken egg yolk; growth inhibition; immunoglobulin; piscirickettsiosis