Effect of chronic protein-energy malnutrition on fecundability, fecundity and fertility in rats.

To assess the effect of chronic protein-energy malnutrition on fecundability (ovulation rate), fecundity (percentage of animals bred that conceived) and fertility (live fetuses at d 18 of pregnancy), 42-d-old female rats were assigned to six groups: two dietary treatment groups and, within each treatment group, three outcome groups. Rats were fed ad libitum (AL) or were chronically restricted (CR) to 50% of AL intake for 28 d before ovulation was assessed and then until implantation and fetal viability were measured. In the ovulation groups, corpora lutea were counted at estrus. In the implantation groups, blastocyst implantation sites were quantified by using Pontamine Blue dye at d 5 of pregnancy. In the viability groups, live and dead fetuses and metrial nodes were counted at d 18 of pregnancy. CR rats had 74% as many corpora lutea as AL rats; however, fecundity did not differ between dietary treatments. CR rats had 71% as many blastocyst implantation sites and 65% as many viable fetuses as AL rats. Chronic malnutrition negatively affected weight gain before and during pregnancy as well as reproductive performance. These findings help to explain why CR rats have fewer progeny.