The Vitamin C Requirement of the Guinea Pig

Abstract

The vitamin C requirement was determined for eighty guinea pigs weighing between 120 and 1040 gm. Each animal, while subsisting for 2 weeks on a scorbutic diet, was given a daily dose of decitrated lemon juice varying, for different individuals, from 0 to 2.2 cc. per 100 gm. of body weight, but mainly in the range of 0.5 to 1.5 cc. per 100 gm. The animals were chloroformed and the degree of protection from scurvy, as indicated by the microscopic structure of the roots of the incisor teeth, was evaluated by Key and Elphick's scale, adapted from the Höjer method. The results indicate that the vitamin C requirement of the guinea pig is directly proportional to the body weight, and is almost exactly 1 cc. of lemon juice per 100 gm. This confirms the observations of Goettsch and Key, Eddy and other investigators, for guinea pigs of about 300 gm. of body weight, and applies to a much wider range of body size. There is no evidence from these data that the young, rapidly growing guinea pig requires a proportionately greater amount of this dietary factor than the adult. This conclusion differs from that of Göthlin and his co-workers with respect to the human requirement, and may be due to a species difference. Silver nitrate staining of the adrenals was found to be of only slight value as a criterion of the degree of protection from scurvy, as compared to the more accurate technic based on the changes in the roots of the incisors. The role of the metabolic rate, which in the case of vitamin B has been found to be of equal importance to body weight as a determinant of the requirement of various species for the vitamin, appears insignificantly small so far as vitamin C is concerned.