Feed processing: a review of the impacts of conditioning time and temperature on feed quality and broilers performance

The most common heat treatment in the poultry feed production industry is pelleting. The purpose of pelleting is to condense smaller feed particles into larger particles in order to increase economic profit by increasing feed consumption and as a result growth performance. From the point of view of feed processing science, as the particle size decreases, the efficiency of mixing and homogenisation of feed improves, and as a result, the efficiency and quality of produced pellets increases. From the point of view of nutrition science, the smaller the feed particles, the greater their contact surface and due to the greater contact of substrates with digestive enzymes, the digestibility of nutrients ameliorates. The presence of heat, moisture and mechanical pressure during pelleting creates chemical and physical changes that may cause alterations in the feed components, growth and health of the bird. The quality of steam and the retention time in the conditioner are important indicators affecting the quality of the produced pellets. The quality of steam is related to the parameters of temperature and humidity inside the conditioner. In addition, increasing the retention time in the conditioner may enhance starch gelatinisation and protein denaturation. Various studies in the field of investigating the effects of conditioning temperature (Ctem) and time (Cti) on the pellet quality and broilers health have provided different results. Therefore, this review will discuss the studies that have been done on the effects of these factors on the pellet quality, broilers performance, gut development and health and nutrient digestibility.