Use of bacterial lipopolysaccharide (LPS) as an immunostimulant for the control of Aeromonas hydrophila infections in rainbow trout Oncorhynchus mykiss (Walbaum).
OBJECTIVE
To determine the effect of lipopolysaccharide (LPS) for the prevention of infection by Aeromonas hydrophila in rainbow trout (Oncorhynchus mykiss Walbaum) fingerlings.


RESULTS
Rainbow trout fingerlings were fed with 0 mg (= controls), 1.875 mg, 3.75 mg, 7.5 mg and 15 mg of LPS per 100 g of commercial feed for 14 days before experimental challenge with A. hydrophila. The results revealed a reduction in mortalities to 5% in the two lowest doses and 15% in the group, which received 15 mg LPS per 100 g of feed, compared with 45% mortalities in the control. LPS exerted a powerful oxidative burst effect and was a potent mediator of phagocytic, lysozyme, bactericidal and antiprotease activities and total protein. However, whereas there were increases in specific growth rate (SGR), feed conversion ratio (FCR) and protein efficiency ratio (PER) in LPS-treated fish, the data were not significantly (P > 0.05) different.


CONCLUSIONS
LPS was effective at preventing disease caused by A. hydrophila and in stimulating the innate immune response of rainbow trout.


CONCLUSIONS
The results of this study highlight the role of LPS in fish disease control.
Nya
E J
EJ
School of Life Sciences, Heriot-Watt University, Edinburgh, Scotland, UK.
Austin
B
B
D000276:Adjuvants, Immunologic / Q000494:pharmacology; D016980:Aeromonas hydrophila / Q000276:immunology / Q000472:pathogenicity*; D000818:Animals; D005393:Fish Diseases / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D016905:Gram-Negative Bacterial Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D007113:Immunity, Innate; D008070:Lipopolysaccharides / Q000276:immunology / Q000494:pharmacology*; D009113:Muramidase / Q000276:immunology; D017686:Oncorhynchus mykiss / Q000254:growth & development / Q000276:immunology* / Q000382:microbiology; D016897:Respiratory Burst
D000276:Adjuvants, Immunologic; D008070:Lipopolysaccharides; D009113:Muramidase