The effect of TEX-OE® in feed during handling and transport of salmon smolt (Salmo salar L.). A preliminary study of the extract from Opuntia sp. (TEX-OE®) effects on primary, secondary and tertiary stress responses

The purpose of this preliminary study was to determine the effect of TEX-OE®, given prior to stressors as tagging, crowding and transfer to seawater. Levels of blood heat shock proteins (hsps) was assessed and related to levels of plasma cortisol, plasma ions, growth and mortality (post seawater transfer). The result shows a positive effect on survival and osmoregulation in the experimental group post-tagging, and could be an effect of the elevated hsp 70 levels. However, as in corresponding studies, osmotic challenges and handling stress has to be severe, exaggerated, or employed on a suspected frail group of fish, to show significant benefits from pre-stress hsp activation. These plausible beneficial effects of TEX-OE after transport and handling of salmon smolt should therefore be further evaluated and documented prior to implementing this concept into commercial salmon production.