Decreased dietary protein or energy intake and plasma growth hormone levels of the pregnant pig, its fetuses and developing progeny.

The effects of low protein diets on plasma growth hormone were studied in pregnant pigs, fetuses and the developing progeny. Pregnant pigs were fed 18%, 3% or 0.5% protein diet throughout the gestation period. At 10, 13 and 15 week of gestation, fetuses were removed from the uterus after the dam had been bled to death. Plasma samples were used for growth hormone determinations. In a second experiment, 2-day old pigs from another set of pregnant pigs fed the diet containing 18%, 3% or 0.5% protein during gestation were cross-fostered to control nursing dams and weaned at 4 weeks of age to a standard diet. Plasma obtained at regular intervals was used for growth hormone determination. Plasma growth hormone was significantly higher in dams fed 0.5% protein after week 13 of gestation. High growth hormone (ten times the dam GH level) was observed in all fetuses irrespective of maternal dietary manipulation. Offspring of severely protein deprived pits (0.5% protein) had significantly elevated growth hormone levels up to 12 weeks of age in spite of cross fostering to a control dam after birth. The data suggest that there is little or no effect of maternal protein restriction on fetal growth hormone levels but the persistent high growth hormone levels in the progeny of severely malnourished pigs indicate a possible impairment of the production, release or catabolism of growth hormone and/or its releasing factor.