MYTHS AND FACTS ABOUT THE EFFECTS OF NANO SELENIUM IN FARM ANIMALS – MINI-REVIEW

Abstract

Selenium plays important roles in antioxidant defence systems, prevents cell damage and is necessary for growth, fertility, and immune system in farm animals. Recently, nano-elemental Se has attracted wide spread attention due to its high bioavailability and low toxicity, because nanometer particulates exhibit novel characteristics, such as great specific surface area, high surface activity, a lot of surface active centres, high catalytic efficiency and strong adsorbing ability and over and above the character of low toxicity of Se0. Nano-Se had similar or higher bioavailability and much less toxicity in broiler chicken and goat as compared to selenite, while in contrast some studies suggested that nano-Se was more toxic than selenite to Medaka fish. Feeding trials have proven that nano-Se supplementation had a positive impact on the growth, feed efficiency of the rumen, fertility and on the antioxidant status of the animals. However, the bioactivity of nano-Se depends on the size, while heat treatment has measurable effect on the size, structure, and bioactivity of selenium nanoparticles. This suggests that if extensive heat exposure is unavoidable during the feed processing, smaller sized selenium nanoparticles should be used. A basic understanding of the absorption, distribution, and clearance and the whole metabolic pathways and mechanisms of nano-Se should be modelled and next to this the understand of negative effects should be investigated and demonstrated in parallel with the novel, promising characteristics as well before using it in common in the animal nutrition.