Formulation of Poultry Diet to Improve Immune Response: A Review

Abstract

Early in the past, poultry diet was mainly formulated to meet maintenance and production requirements, so the focus was on productive performance, and health of birds expected to be involved within these requirements. Thereafter the use of antibiotics as feed additives at subtherapeutic dose was introduced to increase productivity by reducing bacterial colony count in the gut and improving gut equilibrium. That means more concern about health of birds. Recently, arises of poultry welfare concern in addition to the ban of the use of antibiotics as feed additives by European Union from 2006, rushed producers and nutritionists into more concentration on health of birds and immunity when they formulate poultry diets. Hence two ways were adopted to improve bird health and immunity by feed formulation without supplementation of antibiotics as growth promoters. The first one is by using antibiotic alternatives as growth promoters. The other one, which emerges recently, is formulation of feed to meet the needs of cells of the immune system. This means studying its needs for nutrients such as protein, energy, amino acids, vitamins and minerals. There is also, feeding of infected birds when the diet should be formulated in a way to avoid exacerbating the condition by feeding microorganisms and help them to proliferate. This review aims to discuss the role of nutrients and feed formulation in improving poultry health and immunity either through meeting requirements of cells of the immune system or through antibiotic alternatives supplementation or even as modified diet during infections