Effect of dietary fat and cholesterol on milk composition, milk intake and cholesterol metabolism in the rabbit.

Sixteen female rabbits were fed one of four diets during lactation: 1) a commercial stock diet; 2) the stock diet with 5% added lard; 3) the stock diet with 5% lard and 0.25% cholesterol; or 4) the stock diet with 15% lard and 1% cholesterol. By days 30-35 of lactation, maternal plasma cholesterol concentrations were increased approximately 10-fold in group 3 and 100-fold in group 4 does compared to does in group 1. Milk cholesterol concentration was similar over lactation for does in groups 1, 2 and 3, but was approximately 2 times higher in group 4 does. Milk triglyceride and protein concentrations and milk intake by the pups were not significantly influenced by maternal diet. Average cholesterol intake of pups nursed by group 4 does was significantly higher than that of other pups. Although plasma cholesterol concentration was significantly increased in group 2, 3 and 4 pups at weaning (age 5 weeks), there was no significant effect of maternal diet on plasma cholesterol at 6, 7 or 11 weeks of age after pups had been weaned to the stock diet. Similarly, liver cholesterol concentration was increased in pups from group 4 does at weaning, but these differences were no longer apparent at 11 weeks of age. These data suggest that severe maternal hypercholesterolemia induced by dietary fat and cholesterol in the rabbit can result in increased milk cholesterol concentration and consequent cholesterol intake by the pups. However, the associated elevations in pup plasma and liver cholesterol levels at weaning did not persist when pups were weaned to a low fat/low cholesterol diet.