抄録
Of the many investigations reported on the growth of fishes, a few involve measure-ments of the stimulating effect of food on metabolism, i.e. specific dynamic action (SDA). The present series of investigations deals with SDA of fishes to gain information on its growth structure.
SDA is usually measured as total extra oxygen uptake after feeding above a baseline level. In the present paper, SDA of fresh-water fishes fed with Limnodrilus and an artificial diet containing 46% of protein was measured as total extra oxygen uptake, nitrogen excre-tion and the ratio of O2/N to characterize the various aspects.
The results obtained are as follows.
1. The metabolic rate due to SDA increases up to 3-4 hours after feeding and decreases 4-5 hours after feeding. The second increase appears 5-8 hours after feeding.
2. The first increase in metabolic rate due to SDA differs from the second in the ratio of total oxygen uptake and nitrogen excretion.
3. The increase of metabolic rate due to SDA is in proportion to the amount of food intaken.
4. Total extra nitrogen excretion due to SDA decreases with starvation and total extra oxygen uptake decreases more rapidly. Accordingly, the ratio of O2/N decreases with starvation.
