Nutritive value of vegetable protein diets for broiler chickens and selection of diets containing different vegetable or animal proteins

Vegetable protein (VP) diets, i.e. diets based entirely on plant material, are increasingly used by the poultry industry around the world for a variety of reasons, including cost, ingredient availability and growth of the organic product sector. However, VP diets are difficult to formulate because of potential nutrient imbalances, and VP sources can contain anti-nutritive factors, which necessitates processing and nutrient supplementation. In a series of research trials at the University of New England, the nutritive value of VP diets was assessed, in which soybean and canola meals partially or completely replaced fishmeal or meat meal. Diets containing soybean meal or canola meal as protein sources were slightly inferior to diets containing fishmeal but similar to diets containing meat meal. The digestibility of amino acids and minerals was greater for diets containing animal protein sources, but carcass fat content was also higher in birds fed diets containing fish meal. Leg bone development was superior in chicks on diets containing fish meal. The quality of the VP diets was improved through supplementation with carbohydrase and phytase. In feed selection tests, birds preferred diets containing canola meal to diets containing soybean meal, although productivity on the latter was superior. Birds also consumed more of the diet containing meat meal than the VP diets.