Doctoral Dissertations

Date of Award

6-1985

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Human Ecology

Major Professor

Jane R. Savage

Committee Members

Polly G. Martin, Frances E. Andrews, Marjorie P. Penfield, Bert H. Erickson

Abstract

Weanling female rats were fed diets containing one of three levels of Ca (0.3, 0.6 or 0.9%) and one of four levels of Cd (0, 1, 5 or 10 ppm) in the drinking water. One half of each group was bred first as adolescents (55 days) and the other half as mature (110 days) females. Approximately 10 animals from each group were sacrificed after the first pregnancy and the remaining animals after the fourth pregnancy. Reproductive performance, plasma and bone Ca and P and bone density and strength were measured.

After the first pregnancy, offspring of dams treated with 5 or 10 ppm Cd were smaller at birth than offspring of dams treated with 0 or 1 ppm Cd. After the fourth pregnancy, the decreased birth weight was evident only in offspring of dams treated with 10 ppm Cd. Offspring of dams fed 5 or 10 ppm Cd or the 0.3% Ca diet had decreased weaning weight regardless of parity. A 0.3% Ca diet superimposed upon a 5 or 10 ppm Cd intake decreased weaning weight of the male offspring after the first, but not the fourth, pregnancy with the offspring of adolescent dams affected more than those of mature dams. Offspring of dams fed the 0.9% Ca diet did not differ in weaning weight from the offspring of dams fed the 0.6% Ca diet.

Cadmium treatment had no effect on the plasma Ca or the Ca-P ratio. At Cd levels of 5 or 10 ppm the plasma P was increased. The 0.3% Ca diet depressed the plasma Ca the 0.9% Ca diet elevated the plasma Ca and depressed the plasma P when compared to the 0.6% diet. Parity did not affect plasma Ca but, after four pregnancies, plasma P was decreased. Plasma Ca of mature dams was higher than that of adolescent dams but plasma P was unaffected. Bone mineral, density and strength were decreased by the 0.3% Ca diet especially when Cd levels reached 10 ppm. Increasing dietary Ca above normal increased femur Ca of dams fed 1 ppm Cd but did not increase the Ca of the femur of dams given higher levels of Cd. After the first pregnancy, femur Ca of mature dams was greater than that of adolescent dams. After the fourth pregnancy, femurs of mature dams were less strong than those of adolescent dams; however, the density was the same. Increasing dietary Ca above 0.6% lessened the detrimental effects of 5 ppm Cd ingestion on bone density. Mature dams were less affected by the 0.3% Ca 10 ppm Cd treatment than were adolescent dams.

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