Evaluation of standardized ileal digestibility of amino acids in corn, barley, wheat bran fed to primiparous sows during gestation, lactation, and post-weaning period.

This study determined the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA) of corn, barley, and wheat bran in primiparous sows. Four physiological stages of primiparous sows were examined: a gestation stage where sows were restricted-fed, a lactation stage where sows were fed ad libitum, and then two post-weaning stages, an ad libitum-fed phase followed by a restricted-fed phase. A total of 8 primiparous sows fitted with T-cannulas in the distal ileum were assigned to an 8 × 3 Youden square design with 4 diets (corn, barley, wheat bran, and nitrogen [N]-free diet) and three periods, resulting in a total of 6 replicates per treatment. The basal endogenous losses of CP and AA were determined after feeding an N-free diet. For barley, the AID of His, Ile, Lys, and Thr was higher in gestating sows compared to restricted-fed post-weaning sows. For wheat bran, the AID of Ile, Leu, Thr, Val, Ala, Asp, Glu, Gly, Ser, and Tyr was higher in lactating sows compared to gestating sows (P < 0.05). For corn, the AID of CP and most AA did not differ across physiological states. Regarding the SID of barley in gestating sows, only the SID of His was higher than in lactating sows and restricted-fed post-weaning sows (P < 0.01), and the SID of Gly was higher than in lactating sows (P < 0.05). For wheat bran, the SID of Glu, Ser, and Tyr in gestating sows was lower than in lactating sows (P < 0.01). The SID of Val and Tyr in lactating sows was higher than in ad libitum access post-weaning sows (P < 0.05). For corn, the SID of Lys, Ala, and Gly in gestating sows was higher than in lactating sows (P < 0.05). The SID of Ile, Lys, Phe, Thr, and Ala in gestating sows was higher than in ad libitum post-weaning sows (P < 0.05). The findings indicate that similar SID values are found for barley in different physiological stages of primiparous sows under the same diet and feed regime, whether ad libitum or restricted. However, for wheat bran, which has a high fiber content, lactating sows exhibited higher AID values and SID values compared to gestating sows for part of AA. For corn, which has a low fiber content, gestating sows exhibited higher SID values compared to lactating sows and ad libitum post-weaning sows.