Growing pigs were used in a trial to evaluate chemical composition, physical-chemical properties, fecal digestibility of nutrients and energetic values for corn, expanded corn, soybean meal and expanded soybean meal. Proximate analyses, crude energy and specific analyses, as starch gelatinization, acid detergent insoluble nitrogen, urea activity, 0.2% KOH protein solubility and scanning electronic microscopy were performed. Twenty growing castrated pigs averaging 33.630±1.011kg of live weight were used in a digestibility assay. The pigs were allotted to different metabolic cages, in a completely randomized design with five treatments and four replicates. The energetic feed substituted 40% and the proteic feed substituted 20% of a basal diet. Laboratory evaluations showed modification patterns for expanded feed that affected the nutrient digestibility, in comparison to in natura feed. The starch gelatinization increased (P<0.05) nitrogen free extract (NFE) digestibility in expanded corn, and reduced it (P<0.05) in expanded soybean meal, due to expansion process. The expanded corn and expanded soybean meal dry mater and energy digestibility were not affected. However, the soluble protein decreased for the expanded corn, and digestible protein was significantly depressed (P<0.05), but not for expanded soybean meal (P>0.05). The expansion process acts differently on laboratorial and on estimated digestibility for expanded corn and expanded soybean meal.
swine; chemical composition; digestibility; expansion process; corn; soybean meal
