1955 年 21 巻 3 号 p. 197-200
By measuring vitamin B12 amounts of gastric and intestinal contents for various species of fish according to the bioassay using Euglena gracilis the following results were obtained:
1. In case of fishes listed in Table 2, vitamin B12 level of intestinal contents is much higher than that of gastric contents, suggesting that bacteria synthesize vitamin B12 in intestnal tract. The intestinal contents of such high B12 values may be considered as an important B12 source in manufacturing fish solubles from these fishes.
2. The intestinal contents of the fishes shown in Table 3 reveal no singificant increase in B12 level as compared with the gastric contents. It is presumed that vitamin B12 synthetic activities of the intestinal bacteria are only weak or absent in these fishes.