1999 Volume 24 Issue 3 Pages 220-232
The purpose of this study was to invesitigate the effects of the physical consistency of the diet on the metabolites of the masseter muscle on rats fed a pelleted or a powdered diet. The effects were evaluted with 1H-NMR (nuclear magnetic resonance) spectroscopy (1H-MRS) and biochemistry. The other purpose was to examine the relationship between the each type of muscle fiber through identification by ATPase staining and of the metabolites also between the masseter muscle.
Male Wistar rats were divided into two groups, those fed a pelleted diet and those fed a powdered diet, at 3 weeks of age. Rats were fed adlibitum untill 9 or 12 weeks. The contents of the metabolites in the masseter muscle were observed by 1H-MRS. The ratio of different fiber types was determined by ATPase staining.
The following results were obtained.
1. The weight of the masseter muscle of the pelleted diet group was significantly greater than that of the powdered diet group at both 9 and 12 weeks.
2. The share of the cross-sectional area of type 2A fibers in the pelleted diet group was significantly greater than that of the powdered diet group.
3. The contents of creatine and taurine in the pellet diet group were significantly greater than in those in the powdered diet group at 9 weeks of age. The contents of creatine, taurine, anserine, and anserine+carnosine at 12 weeks of age were significantly greater than in those at 9 weeks of age in the pelleted diet group.
4. From the results of a discriminant factor analysis employing the contents of creatine, taurine, anserine and carnosine, there was 100% accuracy in predicting between the pelleted and the powdered diet group at 9 weeks. At 12 weeks there were 91.7% and 83.3% accuracy.
Consequently, it was suggested that the physical consistency of the diet might influence the contents of metabolites and the share area of the fiber type in the masseter muscle.
