Poster Abstracts — Monday, October 3, 2011

Background: Dietary fat and Vitamin D each influence adipose tissue and bone development; the present study investigated possible interactions between these factors in weanling rats.Methods: Female Sprague-Dawley rats (n=32) were divided into an HF group that consumed a high-fat (60% fat, 20% carb) diet and an LF group that consumed a low-fat (15% fat, 65% carb) diet ad libitum.Half the rats in each group received the AIN requirement for Vitamin D (+) whereas the other half received added calcium (to prevent hypocalcemia) but no Vitamin D (-).Results: After 6 wks, the four groups exhibited similar energy intakes, body weights, and % body fat.However, periovarian fat cell size and hepatic lipid content of HF-rats exceeded that of HF+ or LF rats (p<0.005).Hepatic lipid levels from individual rats paralleled concomitant values of periovarian fat cell size (p<0.05)and % body fat (p<0.05).Examination of the trabecular region of the right femur revealed that the structural model index (SMI) was lower in HF than LF rats (p<0.05),indicating a more plate-like vs. rod-like architecture.Percent bone volume, trabecular number, and trabecular thickness were all greater in HF than LF rats (p<0.05),regardless of Vitamin D intake (HF+~HF-and LF+~LF-).Conclusions: The present findings show that: 1) Vitamin D mitigated the increase in hepatic lipid and fat cell size produced by the HF diet; and 2) in contrast to young male rats, the HF diet produced a greater quantity of trabecular bone in female rats.