Milk basic protein enhances the bone strength in ovariectomized rats

We studied the effects of milk basic protein (MBP) on bone metabolism in ov ariectomized (OVX) rats. Five-week-old female Sprague-Dawley rats were ovar iectomized and fed a low-calcium diet (0.009% Ca) for 5 weeks. The OVX rats were divided into three experimental groups: Control group (20% casein), M BP-L group (19.9% casein, 0.1% MBP), and MBP-H (19% casein, 1% MBP) of six animals. The rats were fed each experimental diet for 3 weeks. The bone bre aking strength and energy of femur in the MBP-H group were significantly hi gher than those in the control group. The bone breaking energy of femur in the MBP-L group was also significantly higher than those in the control gro up. There were no differences in the amount of femoral calcium and phosphor us among the three groups, however, the amounts of femoral proline, hydroxy proline and hydroxylysine (typical amino acids of collagen) in the MBP grou ps were significantly higher than those in the control group. These data in dicate that MBP in the whey protein increases the amount of the bone collag en and enhances the bone strength.