The possible effect of Tex-OE® on the pathogenesis of vibriosis in the Gilthead Sea Bream (Sparus aurata L.)

Abstract

Tex-OE® is a patented natural active ingredient derived from the epicarp of the prickly pear, Opuntia ficus-indica, that accelerates the synthesis of heat shock proteins (Hsps) thus helping the organism reduce the deleterious effects of stress and assist the rapid recovery following stress and exposure to aggressive conditions (Gutierrez et al. 2004). Experiments on the effect of Tex-OE® and stress have been carried out on a number of finfish species including guppies, Poecilia reticularia, angelfish, Pterophyllum seafare, gilthead sea bream, Sparus aurata, Atlantic salmon, Salmo salar and rainbow trout, Oncorhynchus mykiss. In this study, experiments were carried out to investigate the immunostimulatory effect of Tex-OE® on gilthead sea bream, Sparus aurata, infected with vibriosis. Particular emphasis was placed on the effects on mortalities, clinical progression of the disease process and Hsp72 levels. The results clearly show that Tex-OE significantly reduces mortalities in experimentally infected fish. This is in line with previous observations (Abela Medici, 2001; Zammit, 2006) and provides further proof of the protective nature afforded by Tex-OE against an ever increasing range of insulting agents. The markedly improved survival is also mirrored by the decreased severity of the chmcal symptoms and the marked delay in the onset of such symptoms. Furthermore, ulceration, fin necrosis and external haemorrhaging were completely avoided by Tex-OE pre-treatment. Equally relevant is the fact that surviving fish had shown symptoms of varying degrees of severity at some time or other post-injection, but the Tex-OE protection had enabled them to fight on and eventually fully recover Bacterial re-isolation is more obvious in the Tex-OE treated fish both in the case where the fish were also pre treated with heat shock as well as in the case where heat shock was not applied. The level of bacterial re-isolation was, in most cases, higher in the heat shocked fish as compared with the non-heat shocked fish. The abdominal cavity always retained the highest residual levels of bacteria.