ASAS/ADSA Midwest Meeting Abstract
Two studies were conducted with crossbred pigs to determine the ratio of digestible threonine (T) and total sulfur amino acids (TSAA) to digestible lysine (L) in corn-based and pearl millet-based diets for growing and finishing pigs. The treatments arranged as a 2x2 factorial consisted of corn-based or pearl millet-based diets and T and TSAA at 65 and 60 % or 70 and 65 % of L. For the growing period (20-50 kg) diets were formulated to contain 16% CP, 3.5 Mcal DE/kg, 0.84% L and 0.15% digestible tryptophan (dT). For the early finishing period (50-80 kg) diets were formulated to contain 13% CP, 3.55 Mcal DE/kg, 0.67% L and 0.13% dT. For the late finishing period (80-110 kg) diets were formulated to contain 10% CP, 3.6 Mcal DE/kg, 0.54% L and 0.1% dT. In the growth study, the body weights and feed intakes of 48 20-kg pigs (24 barrows and 24 gilts) were monitored bi-weekly until the pigs reached 110 kg live weight. Corn-based diet fed pigs had higher (P< .05) ADG and ADF in the growing period but similar (P>.05) ADG in the early and late finishing periods compared to the pearl millet-based diet fed pigs. In all three periods, ADG, ADF and G/F were unaffected (P>.05) by T and TSAA to L ratios. In the 10-d nitrogen and energy balance study, 24 20-kg barrows were assigned to the growing period diets and fed at 5% of BW per day. Pigs fed corn-based diets with T and TSAA at 65 and 60 % of L had a higher (P< .05) energy digestibility. Nitrogen utilization was similar regardless of ratio of amino acids to lysine and grain base. The results indicate that pigs perform equally on corn-based or pearl millet-based diets and increasing the ratio of T and TSAA to L had no effect on pig performance during the growing and finishing periods.
Key Words: Pigs, Pearl Millet, Amino Acids.