In the first experiment, the young carps (four weeks old) were fed on the all vegetable ration (Table 1) and, in the second experiment, the one-age carps on the soybean meal protein and the silkworm pupa protein diets (Table 3). These basal diets were supplemented respectively with vitamin B12 and antibiotics (Table 2 and 4).
The results obtained may be summarized as follows:
1) No growth response was observed on the carps fed vitamin B12, and the carps fed no vitamin B12 supplement contained an ordinary level of the vitamin in their bodies. The fact may indicate that carps are able to supply vitamin B12 for themselves, perhaps by the aid of intestinal microorganisms.
2) Antibiotics tested, both alone and together with vitamin B12, showed no remarkable growth stimulation for carps, differing from the case of chicks and other domestic animals.
3) It was revealed that the quite another APF factor differing from vitamin B12 seems to be necessary for carps.