LAUSR

Male 5-week-old F344 rats were fed four types of experimental diet with different Ca and protein sources for 30 days, and the effect of feeding retort-treated herring bone on Ca absorption and bone metabolism were examined. The experimental diets were as follows: AIN-93G (casein-based standard breeding diet) containing 0.5% Ca from CaCO3 (C); modified AIN-93G containing 0.25% Ca from CaCO3 (L); retorted herring meat with bone containing 0.25% Ca from edible bones (PHB); and retorted deboned herring meat containing 0.06% and 0.19% Ca from retorted bones and CaCO3 (PH). There was no difference in weight increase among the groups during the feeding period. The Ca absorption rate (CAR) in the PHB and PH groups after 4 weeks was slightly lower than that of L, whereas CAR did not differ between PHB and PH. Furthermore, the involvement of absorbed calcium in bone metabolism, as assessed using the bone turnover markers, did not differ between the PHB, PH, and L groups. In conclusion, fish bones rendered edible after retort treatment are a good source of Ca, the nutritional value of which is similar to that of CaCO3, indicating that retort treatment is a suitable cooking method for using fish as a Ca source.