Abstract: The objective of this study was to determine enzyme activity in the digesta from the small intestine of growing pigs and develope an in vitro evaluation system for feed bioavailability using artificial small intestinal juice. Ten pigs (22.77±0.89 kg and fitted with a simple T-cannula at the jejunum) were used in a doubly 5x5 Latin square design. In each period, pigs were offered one of five diets differing in nutrient level for 14 days. The Standard diet (ST) contained 3400 kcal kg-1 of Digestible Energy value (DE) and 17% Crude Protein (CP). The DE for the other four diets was 3600, 3200, 3600 and 3200 kcal kg-1, respectively while the CP level was 21, 13, 13 and 21%, respectively. The small intestinal digesta was collected for determining digestive enzyme activity. Meanwhile, feces were collected for determining in vivo feed digestibility. The results showed that the range of amylase, trypsin, chymotrypsin and lipase activities in the intestinal fluid of growing pigs was 15.52-251.43, 21.24-67.39, 3.45-19.17 and 0.02-3.59 U mL-1, respectively. To establish an in vitro evaluation system for feed bioavailability, Artificial Small Intestinal Juice (ASIJ) was prepared with mixed enzyme reagents based on the mean activities of amylase, trypsin, chymotrypsin and lipase in the digesta used to evaluate the five diets by three-stage enzymatic incubation. By comparing the DE of the five feedstuffs from the in vivo method and the digestibility of the feedstuffs from the in vitro ASIJ analysis, mathematical models for predicting in vivo DE of In Vitro Dry Matter (IVDM), Organic Matter (IVOM) and DE (IVDE) was established (DE = 0.1076xIVDM+0.3741, R2 = 0.34; DE = 0.1276xIVOM+1.6486, R2 = 0.31; DE = 0.4625xIVDE+7.2065, R2 = 0.71). There were no significant differences between the in vitro evaluation results and the developed in vitro method. Therefore, the system in this study based on ASIJ is a convinent and reasonably accurate method for in vitro evaluation of feed bioavailability.
Luoyun Fang, Hongfu Zhang, Feng Zhao, Junjun Wang and Defa Li, 2012. Determination of Digestive Enzyme Activity in the Digesta from the Small Intestinal of Growing Pigs and Development of in vitro Evaluation System for Feed Bioavailability Using Artificial Small Intestinal Juice. Journal of Animal and Veterinary Advances, 11: 1819-1826.