Impact of feed processing technology on nutritional value of pigs feed: A review

Feed industries are seeking new ways to cope with increased raw material costs, and one approach is application of feed processing technology for physical and chemical changes of the feed ingredients and to improve the nutrient quality, stability and hygiene. During last few decades, feed processing has evolved from simple "grind and mix" to more advanced thermal processes such as pelleting, expanding, and extruding which involves mechanical and thermal processing of feed ingredients. Feed processing results in physical and chemical changes of the feed ingredients such as particle size and molecular structure of feed components, which may increase or decrease the nutritional value of the feed ingredients. Thermal processing generally improves starch gelatinization and utilization, protein denaturation, fiber solubalization and improves the nutrient digestibility and performance of pigs. However, processing at high temperature and longer duration also have negative impacts such as Maillard reactions, oxidation of lipids, loss of vitamins and supplemented feed additives, which results into reduced nutritive quality of processed feeds. Therefore, feed miller should consider the interaction between processing and animal nutrition prior to creating formal recommendations for processing parameters. Present review highlights the most commonly used feed processing technology in modern feed industry and its impact on nutritional quality of swine feed.