EFFECT OF PROTEIN SUPPLY DURING PREGNANCY ON BODY-COMPOSITION OF GILTS AND THEIR PRODUCTS OF CONCEPTION

The effect of two levels of nitrogen supply during pregnancy (treatmen t C 28.5 g N kg(-1) DM and treatment L 19.3 g N kg(-1) DM) on body com position of gilts was studied at the same level of ME intake. Body com position was analyzed at mating (n = 11) and at day 108 of pregnancy ( n = 14). From day 0 until day 85 of pregnancy 2.5 kg feed d(-1) was of fered and from day 86 until slaughter 3.0 kg d(-1). Treatments did not affect fresh weight and chemical composition of products of conceptio n (piglets, placentas, uterus and intra-uterine fluids) nor the amino acid pattern of protein of unborn piglets. Mean protein deposition in the maternal body (including the mammary glands) was 74 g d(-1) on tre atment C and 52 g d(-1) on treatment L. Mean protein deposition in the products of conception was 16 g d(-1) on both treatments. Mean matern al fat deposition was 170 g d(-1) on treatment C and 206 g d(-1) on tr eatment L. Protein content of fat-free maternal body, however, was not different between treatments and remained at the same level as observ ed at mating (220 g kg(-1)). Also water/protein ratio was similar in t he maternal body for the two treatments (3.3). Conversion efficiencies of ingested ileal digestible essential amino acids into products of c onception and maternal body, after allowance for maintenance, for lysi ne, methionine + cystine and threonine, were 0.59, 0.47 and 0.67 on tr eatment L and 0.46, 0.34 and 0.44 on treatment C, respectively. It was concluded that the development of products of conception has a higher priority than the development of maternal body.