title: Changes in intestinal microbiota and humoral immune response following probiotic administration in brown trout (Salmo trutta).
abstract: We studied the effect of several lactic acid bacteria (LAB) on the humoral response of brown trout (Salmo trutta). LAB groups (Lactococcus (Lc.) lactis ssp. lactis, Lactobacillus (Lb.) sakei and Leuconostoc (Leu.) mesenteroides) were administered orally at 10(6) colony-forming units/g feed to brown trout for 2 weeks, after which fish were switched to an unsupplemented feed. Blood and intestinal samples were taken from the onset of feeding supplemented diets at 1, 2, 3 and 4 weeks. During the LAB-feeding period, Lc. lactis ssp. lactis, Lb. sakei and Leu. mesenteroides persisted in the fish intestines, but the number of LAB slowly decreased in the intestines after changing to the unsupplemented diet. Only Lb. lactis ssp. lactis and Leu. mesenteroides were detected at levels above 1 x 10(2) colony-forming units/g at the end of the fourth week. In comparison to untreated control fish, the alternative complement activity in the serum was found to be significantly greater in all LAB groups at the end of the second week. Groups supplemented with Lc. lactis ssp. lactis and Leu. mesenteroides exhibited an elevated level of lysozyme activity at the end of the third week, but the group supplemented with Lb. sakei did not exhibit any significant change in lysozyme activity. Serum immunoglobulin levels were higher compared with the control group, but there was no significant difference between the LAB and control groups.
authors.affiliation: Laboratory of Fish Pathology, University of Zaragoza, Zaragoza, Spain. balcazar@unizar.es
authors.forename: José Luis
authors.initials: JL
authors.lastname: Balcázar
authors.forename: Ignacio
authors.initials: I
authors.lastname: de Blas
authors.forename: Imanol
authors.initials: I
authors.lastname: Ruiz-Zarzuela
authors.forename: Daniel
authors.initials: D
authors.lastname: Vendrell
authors.forename: Ana Cristina
authors.initials: AC
authors.lastname: Calvo
authors.forename: Isabel
authors.initials: I
authors.lastname: Márquez
authors.forename: Olivia
authors.initials: O
authors.lastname: Gironés
authors.forename: José Luis
authors.initials: JL
authors.lastname: Muzquiz
mesh_terms: D000821:Animal Feed; D000818:Animals; D017756:Aquaculture / Q000379:methods; D001419:Bacteria / Q000254:growth & development*; D015169:Colony Count, Microbial; D003170:Complement Pathway, Alternative; D007136:Immunoglobulins / Q000096:biosynthesis / Q000097:blood*; D007422:Intestines / Q000382:microbiology*; D007778:Lactobacillus / Q000254:growth & development; D013294:Lactococcus lactis / Q000254:growth & development; D007934:Leuconostoc / Q000254:growth & development; D009113:Muramidase / Q000097:blood; D019936:Probiotics; D014337:Trout / Q000276:immunology* / Q000382:microbiology*
chemical_list: D007136:Immunoglobulins; D009113:Muramidase