RIBOFLAVIN CONTENTS IN THE LIVER OF FISH

1. Individual variations in riboflavin contents in the liver of fish have been assessed with respects to about twenty different species of fish made available since 1941. It has been found that among the same species of fish large and apparently old individuals do not always contain a greater amount of riboflavin in their liver than smaller ones. This phenomenon is partly different from the previous findings by Higashi et al (1942). Generally speaking, the variation between the minimum and maximum contents remained within the range of three times. An extreme case, however, was with “aodai”, Paracaesio caeruleus. Among individuals of this species discrepancy of the riboflavin contents was about seven times. Higashi et al (1942) reported the discrepancy much greater than in the present works. 2. Riboflavin contents in the liver have been compared among different species of fish with respect to the weight ratio of the liver to the body. In some kinds of fish such as sharks, which showed the ratio higher than the other species, the riboflavin content was not found so high as the latter group of fish. The level of their riboflavin content was lower than 3 γ/g. (Fig. 1). 3. Another group of fish showed a tendency where the greater the weight ratio of the liver to thebody, the lower was the riboflavin contents in different individuals of the same species. They were common mackerel, skipjack, Alaska pollack and red salmon (Figs. 2-4).