Extrusion and expansion of cereal grains promotes variable energy yields in pigs, broiler chickens and laying hens

Maximising digestible energy (DE) yield from cereal is fundamental to optimising efficiency in pig and poultry production systems. Given the interaction between the grain structure and composition and DE (or AME) yields in monogastrics, consideration must be given to cost-effective interventions that may improve available energy supply from grains. Processing options such as extrusion and expansion have the potential to significantly disrupt cellular arrangements within a grain and gelatinize starch components, but the resulting increase in energy yield must be significant if the additional processing costs are to be justified. Such responses are poorly defined for specific cereals. The objective of this experiment was to assess the influence of extrusion of milled cereal grains and expansion of hydrated whole cereal grains on DE yield at the end of the small intestine and across the entire digestive tract in pigs, broiler chickens and laying hens. The results suggest that if energy yields from cereal grains for pigs, broiler chickens and laying hens is to be consistently improved, interventions other than extrusion or expansion are required, or a better understanding of the factors influencing specific responses to processing treatments is required. Results from the current experiment reveal that apparently similar cereal grains can respond differently when subjected to identical extrusion or expansion treatments.