Selenium and Poultry Products: Nutritional and Safety Implications

Abstract

Selenium (Se) is both an essential nutrient for humans and animals and a toxicant at excess levels in foods. Its content in animal products reflects that of the feeds consumed.

In order to meet Se nutritional requirements, it is a common animal production technology to supplement livestock and poultry diets with selenium. As a consequence, supplemented animals yield animal products (e.g. milk, meat, eggs) with higher Se concentrations. Because of concern about safety of human consumers, the quantities of selenium that can be supplemented to food-producing animals are strictly regulated. Nutritional and safety implications of selenium supplementation in animal production are discussed. Many studies indicate that selenium from organic sources, e.g. from selenium-enriched yeasts, is more bioavailable compared to inorganic sources and results in more selenium deposited in animal tissues. Problems can arise from accidental overdosing or errors in formulation of Se supplements in food-producing animals, which could lead to animal toxicosis and excessive enrichment of Se in the human food chain. A study is reported in which the effects of a tenfold overdose of Se, administered through Seenriched yeast, have been examined on selenium status and on Se deposition in eggs and edible tissues in laying hens.