Effect of Body Size and Ration on Specific Dynamic Action in the Antarctic Plunderfish,Harpagifer antarcticusNybelin 1947

Abstract

The feeding energetics of the Antarctic spiny plunderfish (Harpagifer antarcticus) were examined with respect to the effect of both ration size and animal size. Fish of different sizes were fed single meals at one of two ration levels (2.5% wet body mass and satiation) to determine the maximum aerobic scope that could be elicited by the specific dynamic action. The excretion rates of ammonia, urea, and fluorescamine-positive substances were also monitored. Neither fish size nor ration had any effect on the factorial aerobic scope of feeding, which suggests that cellular metabolic processes associated with feeding were satiated by relatively small meals. The factorial scope in ammonia excretion was affected by both ration and fish size, indicating that respiration and excretion respond to a meal independently. The duration of the specific dynamic action response (240-390 h) increased with fish size but not ration, whereas both the time to reach the peak oxygen consumption and the duration of the ammonia response increased with ration but not fish size. The percentage of the ingested energy that was expended following feeding (the specific dynamic action coefficient) was high at low rations (approximately 56%) but lower (roughly 10%) at satiation rations. This is because the absolute energetic cost of processing a meal was largely independent of meal size. The change in O:N ratios after feeding was very ration-dependent; at low rations, O:N ratios increased, whereas at satiation rations, the O:N ratios decreased.

Elevated temperature causes metabolic trade-offs at the whole organism level in the Antarctic fish Trematomus bernacchii

“…Animals in this experiment were fed ad libitum, which resulted in a large variance in rations between individual fish (due to differences in feeding activity), which is likely to have affected variance of ammonia as well as faecal excretion in turn. Published rates of ammonia excretion of Antarctic fish are scare (Boyce and Clarke, 1997;Boyce, 1999;Brodte et al, 2006). The most comparable data are those for the energy budget of the Antarctic eelpout (Pachycara brachycephalum), where ammonia excretion is higher than in this study, accounting for about 20% of energy expenditure (Brodte et al, 2006).…”

Juvenile salmon with high standard metabolic rates have higher energy costs but can process meals faster

“…The effect of meal size on subsequent oxygen consumption rates of salmon was similar to that often observed in other animals (Secor 2009): larger meals produced a higher peak elevation and magnitude of SDA; a longer time to reach the peak oxygen consumption; and a longer duration of SDA response. Such trends occur in various species of fishes (Beamish 1974;Jobling & Davies 1980;Boyce & Clarke 1997) and other poikilotherms including snakes ( Toledo et al 2003;Zaidan & Beaupre 2003) and salamanders (Secor & Boehm 2006). More interesting were the differences in the relationship between SMR and SDA among individual salmon.…”

Aerobic scope measurements of fishes in an era of climate change: respirometry, relevance and recommendations

“…However, the exact time will vary across species and temperatures, with cold-water species typically having longer SDA (Secor, 2009). For example, in Atlantic cod (Gadus morhua) fed to satiation the SDA lasts for approximately 85h at 2°C (Perez-Casanova et al, 2010) or 72h at 10°C (Behrens et al, 2012), while in Antarctic fishes living at subzero temperatures SDA durations of 9-16days have been reported (Johnston and Battram, 1993;Boyce and Clarke, 1997). Thus, to be confident in reporting measurements of standard M O2 in animals in a non-digesting state, it is necessary to conduct longterm and uninterrupted measurements of M O2 in a subset of fish without disturbance following different periods of fasting.…”