Use of a probiotic to control lactococcosis and streptococcosis in rainbow trout, Oncorhynchus mykiss (Walbaum).
From a comparison of 125 bacterial isolates recovered from the digestive tract of rainbow trout, Oncorhynchus mykiss, and carp, Cyprinus sp., a culture was obtained which was effective at preventing clinical disease caused by Lactococcus garvieae and Streptococcus iniae when used as a feed additive. The culture, Aeromonas sobria GC2, was incorporated into the feed and fed to rainbow trout (average weight = 20 g) for 14 days at a dose equivalent to 5 x 10(7) cells g(-1) of feed. Whereas the untreated controls experienced losses of 75-100% when challenged intraperitoneally with L. garvieae and S. iniae, the probiotic-treated groups remained healthy with total mortalities of only 0-6%. Formalized and sonicated preparations of GC2 and cell-free supernatant fared less well. The mode of action reflected stimulation of innate immunity, namely an increased number of leucocytes and enhanced phagocytic and respiratory burst activity.
Brunt
J
J
School of Life Sciences, Heriot-Watt University, Edinburgh, UK.
Austin
B
B
D000333:Aeromonas / Q000276:immunology*; D000821:Animal Feed / Q000382:microbiology; D000818:Animals; D017756:Aquaculture / Q000379:methods; D017931:DNA Primers; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005393:Fish Diseases / Q000382:microbiology / Q000628:therapy*; D041981:Gastrointestinal Tract / Q000382:microbiology; D007113:Immunity, Innate / Q000276:immunology*; D017045:Lactococcus / Q000235:genetics*; D017686:Oncorhynchus mykiss; D019936:Probiotics / Q000627:therapeutic use*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA / Q000662:veterinary; D013290:Streptococcal Infections / Q000628:therapy / Q000662:veterinary*; D013291:Streptococcus / Q000235:genetics*
D017931:DNA Primers; D012336:RNA, Ribosomal, 16S