Nutritive utilization of calcium in rats: effects of dietary fat components and vitamin D3 on intestinal resected rats.

The nutritive utilization of calcium was studied in adult rats in which 50% of the distal small intestine (DSI) had been resected and in sham-operated controls one month and three months after the operation. Resection of half the DSI reduced the digestive utilization of Ca as reflected by mineral content in bone. Three months after resection, nutritive utilization of Ca had still not recovered. Feeding the resected rats with a diet in which fat content consisted of equal parts of medium-chain triglycerides (MCT), sunflower seed oil, and olive oil failed to improve nutritive utilization of Ca after one or three months in comparison with a diet containing olive oil as the only source of lipids. Supplementation with vitamin D3 (0.04 mg/100 g diet) enhanced nutritive utilization of Ca in resected rats after one month, the beneficial effect becoming much more patent after three months. At the dose used, vitamin D3 favored calcium deposition in bone tissue. Serum levels of Ca remained unchanged under all experimental conditions, both one month and three months after 50% DSI resection.