Evaluation of the Apparent Ileal Digestibility (AID) of Protein and Amino Acids in Nursery Diets by in Vitro and in Vivo Methods (Report‪)‬

INTRODUCTION Ileal and total tract digestibility should be measured by in vivo trial. The ileal digestibility of amino acid and nitrogen is one of the most valuable measurements for the evaluation of nursery pig diets. However, in vivo methods to evaluate of digestibility require complicated surgery and are time-consuming and costly. In 1991, a model for feed evaluation based on in vitro digestible dry matter and protein was developed by Boisen (1991). Since in vitro digestibility was not influenced by endogenous losses, Boisen and Fernandez (1995) reported that values of in vitro digestibility for protein were higher than those of apparent ileal digestibility and equation for prediction of apparent ileal digestibility of protein and amino acid for pigs diets. Recently, Huang et al. (2000) demonstrated that dialysis tubing and phosphate buffered saline (PBS) solution might be ideal materials for imitating the digestion environment of the intestinal tract. There were significant linear relationships (0.96r-values0.99) between in vivo and in vitro digestibility for amino acids. Most in vitro researches have predicted the equations for relationship and reported the digestibility of feedstuffs compared with in vivo. However, few have examined the relationship between in vitro and in vivo digestibility in modern pigs. Therefore, the objective of this study was to evaluate in vitro prediction of ileal digestibility of protein and amino acids for current nursery pig diets by using pepsin and pancreatin incubations.