Sixty pluriparous sows (average of four farrowing) from commercial line, with initial weight of 262.7 ± 22.50 kg, were used to evaluate the effect of digestible threonine levels on productive and reproductive performance during 16.02 ± 1.17 days of lactation. The animals were distributed to a completely randomized design, with 4 diets and 15 replications, considering the sow the experimental unit. The diets were formulated with four levels of digestible threonine (0.608, 0.646, 0.684 or 0.722%), the corresponding to 64, 68, 72 and 76% respectively, with digestible lysine ratio). Digestible threonine levels did not influence feed consumption, which were 4.7 kg/anim.day. The individual daily digestible threonine consumption ranged from a linear fashion among the threonine levels. There was no effect of dietary digestible threonine levels on productive and reproductive performance of lactating sows. The level of 0.608%, corresponding to digestible threonine: digestible lysine ratio of 64%, meets the digestible requirements of threonine of sows in the lactating period.
amino acids; nutritional requirements; pigs
