Amino acid fortification of bread fed at varying levels during gestation and lactation in rats.

The effects of protein quality improvement of white bread fed to female rats during pregnancy and lactation, under varying degrees of adequacy in food energy, on growth and brain development of the offspring have been studied. Weaning weight and the weight, protein and DNA of whole brain and major regions of the brain at weaning were determined. Lysine addition significantly increased all parameters, and threonine addition gave additional significant increments. Restricting energy intake decreased most parameters independent of protein quality. Brain cellularity was significantly higher in offspring of dams fed lysine and threonine fortified bread than in offspring of dams fed casein. All parameters measured in the offspring of dams fed lysine and threonine fortified bread at 70% ad libitum consumption were significantly increased over the values obtained in the offspring of dams fed unfortified bread ad libitum even though they had consumed 13% less protein and dietary energy during the pregnancy and lactation period. The implications of these findings for practical problems in human nutrition are considered.