Effect of Type of Carbohydrate on Vitamins B and G Potency of Feces Voided by Rats. ∗

Abstract

Summary

Data are presented which indicate that the type of carbohydrate used in vitamin B and G deficient diets is an important factor in determining whether or not coprophagy will vitiate results when accurate assays of vitamins B and G are desired. Coprophagy appears to be of little consequence when sucrose is used as the sole source of carbohydrate, while dextrinized corn starch offers the possibility of introducing serious errors and incorrect conclusions if rats resort to coprophagy when this carbohydrate is used.

Experiments are now in progress in which an attempt is being made to find an explanation for the results described, and the study is being extended to include other types of carbohydrates.

In a previous publication from this laboratory 1 the danger of coprophagy, as it affects the assay of vitamins B and G, was discussed. Similar observations had been reported by Roscoe. 2 More recently Booher and Kaneko 3 have submitted data which led them to conclude that their assays for vitamin B (B₁) were not vitiated by coprophagy. The last mentioned investigators used raw corn starch as the source of carbohydrate. Since Roscoe had reported that she was unable to obtain characteristic growth responses from coprophagous rats when raw corn starch served as the source of carbohydrate, it seemed highly probable that the type of carbohydrate might be an important factor worthy of further study. This possibility has been further suggested by data obtained in this laboratory during a somewhat related investigation in which it was found that the quantity of vitamins B and G required to produce a unit increment of growth was considerably greater when sucrose was fed as the source of carbohydrate than it was when dextrinized corn starch was used.

The experiments here described were initiated to determine the extent to which growth responses in coprophagous rats could be affected by substituting carbohydrates of various types in the usual basal ration deficient in vitamins B and G. Among the carbohydrates under investigation at present are: corn starch, dextrinized corn starch, glucose, sucrose, and lactose. While the results to date are insufficient for a complete statement, the differences obtained with diets containing sucrose and corresponding diets containing dextrinized corn starch are sufficiently marked to justify a preliminary note at this time.