Le zinc dans l'alimentation du porc: Oligo-élément essentiel et risque potentiel pour l'environnement

Abstract

Zinc is an essential trace element which plays a role in many biological functions. Loss of appetite, diarrhoea, growth retardation or parakeratosis are symptoms of zinc deficiency that occur in pigs fed non zinc supplemented diets. Due to a lack of knowledge of both the actual zinc requirements of pigs and the factors that affect its availability in pigs, this element is often oversupplied in pig feeding. Such a practice has a direct adverse effect on the environment, particularly in areas of intensive pig farming. To overcome this problem and avoid any wastage of dietary zinc, the supply should be better adjusted to the requirements and zinc availability should be improved as much as possible. Relying on a literature review, pig zinc requirements were estimated according to body weight. The addition of phytase improves zinc bioavailability and 1000 units of microbial phytase/kg of diet were estimated to be equivalent to the addition of 24 and 19 mg/kg zinc added as zinc sulphate in the diets of piglets weighing 15 kg and 25 kg, respectively. Such estimates are worth being validated experimentally. Moreover, the actual impact of other dietary components on zinc availability remains to be assessed.