Protein requirements for the pregnant rat Besoins protéiques de la ratte gestantle Eiweissbedarf schwangerer Ratten

Abstract

Pregnant and non-pregnant rats fed on casein diets of different protein value during 20 days were used to study the effect of the protein value of the diet on the apparent Net Protein Utilization and for re-evaluating protein requirements during pregnancy. For both mother and products no nitrogen of the intake is retained as gain (apparent Net Protein Utilization equals zero) when the diet provides 4.95 Net Dietary protein Cal%. In this condition the mother delivers some of her own body nitrogen to build the products. The mother herself attains zero apparent Net Protein Utilization when the diet provides 6.1 Net Dietary protein Cal%. For the complex mother and products the end of pregnancy is attained with no gain of nitrogen when the intake, referred to kg<sup>0.78</sup>/day, equals 6.0 Net Dietary protein Cal and 122.5 Cal. To obtain no gain or loss of nitrogen in the mother’s carcass an intake of 8.3 Net Dietary protein Cal/kg<sup>0.73</sup>/day and 130.0 Cal/kg<sup>0.73</sup>/day s