Amino Acid Availabilities in Soybean Meal, Sunflower Meal, Fish Meal and Meat and Bone Meal Fed to Growing Pigs1

Eight barrows (40 kg initial weight) fitted with simple T-cannulae 5 cm from the ileocecal junction were used in a replicated 4 × 4 Latin square design experiment to determine the ileal and fecal availabilities of amino acids (AA) in cornstarch-based diets formulated to contain 14% crude protein by supplementation with soybean meal (SBM), sunflower meal (SFM), fish meal (FM) or meat and bone meal (MBM). Average ileal availabilities of the indispensable AA were highest for SBM (79.7), followed by FM (77.8), SFM (75.5) and MBM (71.7%). Of the indispensable AA, threonine was lowest in ileal availability in SBM (71.6), SFM (68.6) and MBM (63.4%), while phenylalanine had the lowest ileal availability in FM (68.3%). In general, fecal AA availabilities were higher than ileal AA availabilities. These differences were largest for threonine and smallest for methionine. Fecal digestibilities of dry matter and protein in FM were 3 percentage units higher when determined with the total collection method compared with chromic oxide or dysprosium. With the remainder of the protein supplements, there were no significant differences in digestibility due to method of determination. Method of preparation of feces before N analysis (oven dried vs freeze-dried vs wet feces) did not affect protein digestibility measurements.