Neem (Azadirachta indica) leaf and kernel and their effects on production and physiology of poultry: a review

The heavy demand for cereal grains and legumes by industries, humans and animals has given rise to increase in their prices and consequently in the costs of livestock feeds. There is a need therefore for the exploitation of other alternative noncompetitive feed resources in other to replace cereal grains and legumes in poultry diets. Many tropical plants produce leaves and seeds that are little known in poultry nutrition. The identification, processing and use of such leaves and seeds in poultry diets will go a long way in reducing the dependence on conventional feedstuffs. Neem is a tropical tree plant that yields heavily in fruits/seeds. The leaves and other parts of the plant are used in local medicine, and the leaf and seed have been reported to be moderate in protein, digestible fibre, carbohydrates and ash and could contribute significantly to the needs of poultry. The seed kernel has an amino acid profile similar to soybeans that are commonly used as protein feedstuff in poultry diets. However, neem contains a variety of toxic substances that are harmful to poultry. Efforts have been made to processed neem and remove toxic substances by toasting and autoclaving with great success. Research to date has studied the effects of neem leaf and seed on physiology and organ anatomy of poultry. The use of neem in poultry diets and their effects on blood chemistry and haematology have been reported. This review will cover the nutrient composition of neem leaf and seed meals and their effects on growth, laying performance, organ weight and blood constituents of broilers and laying birds.