Apparent Specific Dynamic Action Research Articles

Apparent Specific Dynamic Action of Food in the Fish Blennius pholis

Apparent Specific Dynamic Action of Food in the Fish Blennius pholis

An apparent specific dynamic action in Mytilus edulis L.

The results of experiments recorded by Bayne & Scullard (1977) confirmed earlier studies (Bayne, 1973) in describing a decline in the rate of oxygen uptake (Vo2) by Mytilus edulis during starvation, eventually reaching a steady-state value, called the standard rate of oxygen consumption. Earlier experiments had also shown that if such starved mussels were fed, oxygen uptake increased rapidly to a high level called the active rate of oxygen consumption (Thompson & Bayne, 1972; Bayne, Thompson & Widdows, 1973). Some of this increase in metabolic rate is undoubtedly due to an increased filtration rate that is stimulated by the presence of food (the ‘mechanical cost of feeding’ discussed by Bayne et al. 1976), and part is due to the ‘physiological costs of feeding’, which includes energy utilized in digestion and assimilation of the food, and energy that is lost during deamination and other catabolic processes that accompany digestion (Warren & Davis, 1967). Increases in metabolic rate associated with feeding have been called the specific dynamic action (SDA) of the ration (see Harper, 1971, for a discussion) or the apparent SDA (Beamish, 1974)5 and they have been related to aspects of protein metabolism (Krebs, 1964). This paper describes the results of some experiments designed to examine the relationships between SDA and ammonia excretion in Mytilus edulis L.

Apparent Specific Dynamic Action of Largemouth Bass, Micropterus salmoides

Oxygen consumption attributable to apparent specific dynamic action (SDA) was measured in relation to feeding level and body weight in largemouth bass, Micropterus salmoides, forced to swim at 1.7 body lengths/s (BL/s). Apparent SDA rose curvilinearly with ration size, the coefficient increasing with weight of bass. For a ration of fixed percent body weight/day, apparent SDA increased curvilinearly with weight of bass, the rate being most pronounced at higher levels of food intake. Apparent SDA expressed in energy units as a percent of ration ingested did not differ significantly with weight of fish or meal size. The overall mean apparent SDA ± SD was 14.19 ± 4.19% of the energy ingested. Time required for oxygen consumption to subside to pre-feeding levels increased with ration size and weight of bass.Over the range of swimming speeds from 1.4 to 2.5 BL/s, there were no differences in apparent SDA of similar size bass fed a ration of 4% body weight/day. Similarly, time for elevated levels of oxygen consumption to return to prefeeding rates was independent of swimming speed.