• Asian-Australasian Journal of Animal Sciences
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• v.20 no.8
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• pp.1266-1271
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• 2007

This study examined effects of calcium supplemented milk on bone loss in ovariectomized rats. Twenty four Sprague-Dawley female rats, 7 weeks-old, were divided into 4 groups, ovariectomized and fed diets containing: 1) control, no Ca supplemented milk, 2) ovx 1, Ca carbonate supplemented milk, 3) ovx 2, ionized Ca supplemented milk, and 4) ovx 3, nano Ca supplemented milk. All rats were fed 1 ml of milk containing 20 mg supplemented Ca. After 18 wk feeding, body weight gain and food efficiency ratio were significantly different between ovx 1 and ovx 3. Serum concentration of calcium and phosphorus were not different among groups. However, there was a significant difference in calcium content of dry femoral weight in ovx 3 compared with the control and ovx 2. In addition, femoral bone mineral density ($g/cm^2$) was significantly greater in ovx 3 than in other groups (p<0.05). The ovx 3 group showed the highest stiffness (N/mm), maximum energy (N) in femur and trabecular bone area (%). The present study indicated that nano Ca supplementation in milk may be an effective way to enhance bone calcium metabolism for ovariectomized rats.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.3
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• pp.454-458
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• 2014

In this study, we examined the ionization rate and permeability of nanocalcium prepared from oyster shells with various particle sizes. Four particle sizes of the calcium samples were prepared by centrifugation according to their density disparity in alcoholic solution: NC (normal calcium), C-1 (supernatant of 1,000 rpm), C-2 (supernatant of 2,000 rpm), and C-3 (supernatant of 3,000 rpm). Particle sizes of NC, C-1, C-2, and C-3 were $2,280.3{\pm}64.3nm$, $521.3{\pm}83.3nm$, $313.9{\pm}29.5nm$, and $280.0{\pm}3.4nm$, respectively. C-3 showed a slight increase in ionization rate compared with the other calcium samples, but their differences were not significant. Dialysis membrane-employed analysis showed that nanocalcium permeability increased as its particle size smaller; 32% of C-3 nanocalcium was transported to the outside of the membrane, whereas C-1 showed a 25% transport rate. We determined the permeability of the nanocalciums by using rat intestinal sacs, in order to provide different intestinal environments depending on pH level. Nanocalcium generally showed a higher permeability at pH 7, which represents an ileum environments compared to the duodenum and jejunum environments at pH 4.2 and pH 6.2, respectively. However, C-3 calcium showed the highest permeability, followed by C-2, C-1 and NS calciums. This result shows that the size of calcium positively affected its permeability in the intestinal sac. Taken together, nano-sized calcium derived from discarded oyster shell shows improved permeability in intestinal environments.