Forty crossbred sows (Landrace x Large White) from the first parturition, with average weight of 182.2 ±16.5 kg, were used to evaluate the total lysine levels (0.95, 1.03, 1.10, 1.18, and 1.25%) in the diet, maintaining the same amino acids relation, during lactation (21 days). A completely randomized blocks design, with five treatments, eight replicates, where the sow was considered the experimental unit, was used. Total feed intake did not change according to the treatments, where the sows were daily fed, in average, 4.2 kg. Lysine intake and sows weight at weaning linearly increased, according to the lysine levels in the diet. Although the sows weight variation was not significant, the sows fed diets with lysine levels equal or superior than 1.18% showed smaller absolute values of weight loss during lactation. Weight gain and weaning weight of piglets and litter, backfat thickness and the number of days to return to estrus of sows after weaning were not affected by the dietary lysine levels. It was concluded that the level of 0.95%, correspondent to a daily intake of 40 g total lysine, met the lysine requirements of lactating primiparous sows.
estrus; intake; litter; reproduction; sows; weaning
