The effects of energy and lysine intake during late gestation and lactation
on the reproductive performance of primiparous sows were evaluated using 36 gilts. Sows were allocated to six dietary
treatments according to a 32 factorial arrangement and each treatment had six replicates. Three energy levels [low (EL),
medium (EM) and high (EH)] and two lysine levels [low (LL) and high (HL)] were used. Gilts with HL intake had more
weight (P=0.004) and backfat thickness (P=0.047) gain during gestation. Similar changes in sow body conditions were
observed during lactation. HL intake resulted in higher litter birth weight (P=0.001), weaning weight (P=0.001) and
growth rate (P<0.001) and shortened wean-to-estrus interval (P=0.001). Energy intake influenced the fat and lactose content while lysine intake influenced the total solids and protein content in milk and colostrum. Gilts with HL had higher insulin and lower creatinine levels during postfarrowing and weaning, while triglyceride concentration at weaning increased with increasing of energy intake. The basal and pulses of LH were also influenced by lysine intake. In conclusion, higher lysine intake than those recommended by National Research Council (1998) could improve performance during late gestation and lactation in primiparous sows.