Control of saprolegniosis in the eel Anguilla australis Richardson, by Aeromonas media strain A199

The probiotic activity of Aeromonas media strain A 199 for the control of saprolegniosis at low water temperatures was trialled in a laboratory-based challenge using the eel, Anguilla australis Richardson. Eels were challenged in the presence of a physiological and physical stress akin to that preceding the winter outbreaks of saprolegniosis in farms. The concentration of Saprolegnia parasitica cysts was 9 +/- 1.2 cysts/ml for the initial challenge. Morbidity due to saprolegniosis was low, at 27% in A199-treated tanks, in comparison to the 44% recorded for the non-treated control tanks. The subsequent addition of live A199 cultures to the treatment tanks resulted in the recovery of fish suffering from saprolegniosis (p = 0.038), with temperature appearing to be a factor regulating the effect of A199. It was concluded that A199 is a potential agent for the management of winter outbreaks of saprolegniosis in eels. (C) 2004 Elsevier B.V. All rights reserved.