A strain-specific eating pattern as a factor limiting the transmissibility of caries activity in rats.

Abstract In Experiment I the caries activity of the Osborne-Mendel (O-M) and the NIH Black rat (BR) were compared under identical environmental conditions and it was shown that the low activity of the BRs was not due to the lack of implantation of a specific cariogenic oral microflora or to the inadequacy of the caries test diets used. The results of recording food intake of these free-fed rats showed that the O-Ms consumed more food and took more frequent meals than the BRs. In Experiment II the same high-frequency eating pattern (36 meals per day) was imposed on the BRs and O-Ms with the aid of an automatic programmed-feeding machine. The significant increase of caries activity in the BRs on this regime is in keeping with the hypothesis that the inborn habit of short and infrequent eating in the BRs, resulting in infrequent presence of substrate for cariogenic micro-organisms, may be one of the major factors responsible for the low level of caries activity of free-fed BRs.