This study was designed to determine whether feeding an Aspergillus product would influence growth or feed utilization and intestinal mucosal cell function as indicated by uptake of methionine and glucose by isolated intestinal brush border membrane vesicles (BBMV). In Experiment 1, 24 weanling pigs were paired by sex, BW, and litter and were allotted, within pairs, to either an 18% CP corn-soy diet (control) or the same diet supplemented (.15%) with an Aspergillus product. There were no differences (P > .05) in ADG, daily feed intake, or feed/gain between the two groups. In Experiment 2, 24 weanling wether lambs were paired by BW and were randomly assigned within pair to a 14% CP diet containing 61.1 % cracked corn, 17.3% soybean meal, and 15% ground orchard grass hay (control) or the same diet fortified (.07%) with an Aspergillus product. There were no differences (P > .05) in ADG, daily feed intake, or feed/gain between the two groups. Enrichment of alkaline phosphatase in BBMV used in transport studies were 12.7-fold higher in pigs and 5.6-fold higher in lambs over the original homogenate. / Ph. D.