Physiology and Endocrinology: Nutritional Regulation of Reproduction

cass traits as barrows fed the C-SBM diet (P > 0.10). In Exp. 2, 60 barrows (initial and final BW of 74.6 and 104.5 kg, respectively) were used to estimate the dTrp requirement. The levels of dTrp used in Exp. 2 were 0.06, 0.08, 0.10, 0.12, or 0.14%. Response variables were growth performance, PUN concentrations, carcass traits, and pork quality. The dTrp requirement was estimated to be 0.102%. In Exp. 3, 4, and 5, barrows (n = 60, 60, or 80, respectively) were allotted to five dietary treatments supplemented with crystalline L-Trp, and PUN concentration was the response variable. The levels of dTrp in Exp. 3 (BW was 30.9 kg) were 0.13, 0.15, 0.17, 0.19, or 0.21%. The dTrp requirement was estimated to be 0.167%. The levels of dTrp in Exp 4 (BW was 51.3 kg) were 0.09, 0.11, 0.13, 0.15, or 0.17%. The dTrp requirement was estimated to be 0.134%. The levels of dTrp in Exp. 5 (BW was 69.4 kg) were 0.07, 0.09, 0.11, 0.13, or 0.15%. The dTrp requirement was estimated to be 0.096%. These data indicate that the dTrp requirements of barrows weighing 30.9, 51.3, 69.4, and 74.6 to 104.5 are 0.167, 0.134, 0.096, and 0.102%, respectively.