One experiment was carried out to determine the lysine (Lys) and metabolyzable energy (ME) levels for breeding gilts. One hundred and eight Seghers® gilts (Large-White x Landrace/Large-White) were alloted to a complete randomized design with a 3x3 factorial design, three levels of Lys (0.55, 0.75 and 0.95%) and three levels of ME (3,100, 3,250, and 3,400 kcal ME/kg). The treatments were the same from the beginning of trial (housing) to the slaughter (30 days of gestation). There was only effect of ME on the reproductive performance, without effect of Lys or the ME x Lis interaction. The number of corpora lutea increased linearly with the highest level of ME and weigh at artificial insemination (AI-weight). Likewise, the numbers of total and live embryos increased linearly with the highest level of ME. The lowest concentration of plasma urea nitrogen was obtained with 0.55% of Lys and 3,400 kcal ME/kg. The weight and back fat thickness at AI, plasma glucose, progesterone, and insulin were not influenced by the treatments. The requirement for total lysine for breeding gilts is not higher than 0.55%. The minimum energy recommendation is of 3,400 kcal ME/kg.
corpora lutea; embryos; piglets; ovulation; plasma urea nitrogen; reproduction
