Abstract
The effect of plant estrogens (genistin and alfalfa-extract) on the body weight, feed consumption, litter weight gain, mammary weight and mammary nucleic acid contents (DNA, RNA) of lactating hamster was investigated. Genistin (G) was isolated from defatted soybean flakes, and alfalfa-extract (A1-E) was prepared from alfalfa meal by extraction with acetone and ethylether. Genistin and A1-E were added to the estrogen-free basal diet at the level of 1, 5, 10 (for G) and 8.3 (for A1-E)mg/g of diet and fed to the lactating hamster from the 2nd to 12th day after parturition. Addition of G and A1-E decreased feed consumption, had little effect on the litter weight gain and mammary nucleic acid content, and increased feed efficiency for milk production. In the restricted feeding groups, the feed consumption of the estrogen-free basal diet was restricted to about the same amount as the consumption of the G or A1-E administered group. The restricted feeding brought the decreases of the litter weight gain, mammary weight and mammary nucleic acid content in the lactating hamster. The evidence obtained supports the suggestion that plant estrogen may be effective to improve the lactational performance of the hamster after parturition.
