Practical applications of agricultural wastes in poultry feeding in Mediterranean and Middle East regions. Part 1: citrus, grape, pomegranate and apple wastes

In the last few decades, there has been growing interest in the use of agricultural wastes as feed ingredients in poultry diet to maximise their potential output. Many wastes of the agroindustry (e.g. citrus, grape, pomegranate and apple processing) have significant antioxidant properties, due to their bioactive compounds (polyphenols, flavonoids). It has been reported that citrus and grape wastes can be successfully included in broilers diets up to 3%, which increases carcass and meat yield and reduces abdominal fat (by 10% on average). Pomegranate can be included up to 2% supplementation and is associated with improved feed efficiency (by 12% in broilers). Apple by-products can be formulated up to 5% in diets for meat-type broilers and up to 10% in laying hens diet to reduce oxidative stress. Therefore, the application of these by-products in poultry diets could combine the positive effects of improving the qualitative characteristics of animal products as well as human health with reducing concerns related with their disposal into the environment. In this review, the findings on the effects of some agricultural wastes, from typically-cultivated products originating in Mediterranean and Middle East regions on poultry performance, carcass characteristics, immune response, plasma constitutes, intestinal microbiota and enzyme activity are reviewed and discussed.