INFLUENCE OF VITAMIN E SUPPLEMENTATION ON DERMAL WOUND HEALING IN TILAPIA, OREOCHROMIS NILOTICUS

Abstract

Aquaculture is responsible for a 20 million tonnes increase in fish production over the last decade, with an estimate of 48 million tones in 2005. The global increase in aquaculture production was made possible through the introduction of new areas, species, and practices and through increased production from existing systems. Nutrient pollution from aquaculture and intensification of fish production, in turn, may cause declines in aquaculture productivity by promoting outbreaks of disease among the fish. Antibiotics as feed additives, which played an important role for controlling diseases in the past, have been widely criticized for the negative impacts to the surround aquatic systems. The potential substitute for antibiotics are the so called nutraceuticals, multi-physiological, bioactive and pollution-free additives, acting as immuno-stimulants that improve resistance to diseases by enhancing non-specific defence mechanisms. In the present chapter we studied the effects of vitamin E supplementation in the process of induced wound healing in Nile tilapias Oreochromis niloticus. During a period of 60 days, fish (initial body weight=30g) were fed two experimental diets, supplemented (450 mg/kg diet) or not with vitamin E. Thereafter, all animals were anaesthetized and submitted to dermal wounds. The histomorphometric assessment was checked after 3, 7, 14, 21 and 28 days post-wounding. The cicatricial retraction and appearance of the wounds were monitored during the trial. Moreover, the histomorphometry of the mucous cells, chromatophores, inflammatory cells, fibroblasts, collagen fibers and scales were also used as indicators for the wound healing capacity. The rate of wound retraction was significantly higher in the vitamin E supplemented group. Such healing was a result of an increase of inflammatory cells, mucous cells, chromatophores and collagen fibers. The results indicate that fish fed vitamin E rich diet have enhanced dermal wound healing capacity.