The requirements of lactating sows for total lysine and metabolyzable energy (ME) to support subsequent reproduction performance were evaluated. One hundred and twenty sows were used. The treatments were constituted of eight diets (factorial arrangement of four levels of total lysine: 0.75, 0.90, 1.05 and 1.20%, and two levels of ME: 3,250 and 3,400 kcal ME/kg). There was interaction between lysine and ME on the plasma urea nitrogen (PUN), with linear decrease effect on level of 3,250 kcal ME/kg, and quadratic effect on level of 3,400 kcal ME/kg, with the lowest level of PUN with 1.06% lysine. The reproductive performance in the subsequent farrowing was not affected by the lysine levels and ME, hence, neither the total born nor the born alive differed among the treatments. There was no convincing information to support that the requirements of total lysine and ME for lactating sows were higher than 0.75% and 3,250 kcal/kg.
Feed intake; litter; plasma urea nitrogen; weaning-to-estrus interval
