Oral administration of formalin-inactivated cells of Aeromonas hydrophila A3-51 controls infection by atypical A. salmonicida in goldfish, Carassius auratus (L.)

There has been increasing interest in the use of probiotics in aquaculture to control fish diseases (e.g. Douillet & Langdon 1994; Gildberg, Mikkelsen, Sandaker & Ringo 1997; Kennedy, Tucker, Neidic, Vermeer, Cooper, Jarrell & Sennett 1998; DeSchrijver & Ollevier 2000; Robertson, O'Dowd, Burrells, Williams & Austin 2000), and a diverse range of Gram-positive (such as Carnobacterium inhibens) (Robertson et al. 2000) and Gram-negative bacteria, including Vibrio alginolyticus (Garriques & Arevalo 1995), have been evaluated at various times. However, the possible use of probiotics to control diseases of ornamental fish has been neglected. Consequently, following previous success with live (Irianto & Austin 2002) and inactivated probiotics in salmonids (Irianto & Austin, in press), research has focused on the usefulness of inactivated bacterial preparations for the control of atypical Aeromonas salmonicida infections in goldfish, Carassius auratus (L). Goldfish, of average 40-50 mm in length, were obtained from a commercial farm in England, and maintained in aerated re-circulating dechlorinated fresh water at 17 °C. Their health status was examined immediately upon arrival in the aquaria and at 1-2-week periods thereafter (after Austin & Austin 1989).