摘要：A rapid in vitro method was developed to predict digestibility of protein in feed ingredients for swine. A total of 72 pigs (initial wt., 25kg) were used in three conventional digestion trials to measure the protein digestibility of feed ingredients. Feed ingredients studied were corn, sorghum, alfalfa meal, wheat bran, rice bran, soybean meal, meat and bone meal, and sunflower meal. The in vitro method was based on the digestion of an 50 ml aqueous protein suspeion (93.75mg) at 37℃, pH8, with mixed enzymes of trypsin, chymotrypsin and peptidase. The pH of the protein suspeion after incubation with proteolytic enzymes was recorded. The pH of the protein suspeion after a 12-min incubation with the proteolytic enzymes correlatted well with the in vivo protein digestibility determined from the pig bioassays. The regression of in vivo digestibility (Y) on pH value (X) for nine feed ingredients was Y=361.35-40.03X(r=0.84, P0.01, RSD=6.58). Excluding alfalfa meal and wheat bran, the correlation coefficient R and residual standard deviation (RSD) were improved and the regression was Y=315.58-33.19X(r=0.98, P0.01, RSD=1.62). These results suggest that the protein digestibility of feed ingredients for swine can be predicted from a rapid enzymatic method.