Effects of isoquinoline alkaloids on apparent ileal digestibility of amino acids, acid hydrolyzed ether extract, and starch by young growing pigs fed corn-soybean meal diets

An experiment was conducted to test the hypothesis that a preparation of isoquinoline alkaloids (IQ) obtained from Macleaya cordata and added to corn-soybean meal diets increases the apparent ileal digestibility (AID) of amino acids (AA), crude protein (CP), starch, and acid hydrolyzed ether extract (AEE) when fed to young growing pigs. Thirty-two ileal cannulated barrows (initial body weight = 12.19 ± 1.38 kg) were allotted to a randomized complete block design with four diets and eight replicate pigs per diet. Diets were supplemented with 0, 90, 180, or 360 mg/kg IQ and with 0.40% chromic oxide. Diets were fed for 27 d and ileal digesta were collected on days 13 and 14 (period 1) and on days 26 and 27 (period 2). Effects of IQ inclusions were analyzed using contrast statements, and differences between periods were analyzed using a repeated measures statement. A quadratic increase (P < 0.05) in the AID of Thr, Trp, Val, Pro, and Tyr was observed in period 1 as IQ was included in the diets, and AID of CP, Arg, His, Ile, Leu, Met, Phe, Thr, Trp, Val, Pro, and Tyr was greater in period 2 than in period 1 (P < 0.05). In period 1, a quadratic increase (P < 0.05) was observed for the AID of starch as IQ increased in the diet, but the AID of starch was less (P < 0.05) in period 2 than in period 1. No differences among treatments or periods were observed for AID of AEE. Results indicate that inclusion of approximately 90 mg/kg of IQ in diets for weanling pigs may increase the AID of starch and some AA.