Juvenile sturgeon exhibit reduced physiological responses to exercise

Abstract

SUMMARYExperiments were conducted to determine the physiological responses to exercise of Atlantic sturgeon (Acipenser oxyrhynchus) and shortnose sturgeon (A. brevirostrum). We measured the rates of oxygen consumption and ammonia excretion in both species and a variety of physiological parameters in both muscle (e.g. lactate, glycogen, pyruvate, glucose and phosphocreatine concentrations) and blood (e.g. osmolality and lactate concentration) in juvenile shortnose sturgeon following 5 min of exhaustive exercise.In both species, oxygen consumption and ammonia excretion rates increased approximately twofold following exhaustive exercise. Post-exercise oxygen consumption rates decreased to control levels within 30 min in both sturgeon species, but post-exercise ammonia excretion rates remained high in Atlantic sturgeon throughout the 4 h experiment. Resting muscle energy metabolite levels in shortnose sturgeon were similar to those of other fish species, but the levels decreased only slightly following the exercise period and recovery occurred within an hour. Under resting conditions, muscle lactate levels were low (<1 μmol g–1) but they increased to approximately 6 μmol g–1 after exercise, returning to control levels within 6 h. Unlike similarly stressed teleost fish, such as the rainbow trout, plasma lactate levels did not increase substantially and returned to resting levels within 2 h. Plasma osmolality was not significantly affected by exercise in shortnose sturgeon.Taken together, these results suggest that shortnose and Atlantic sturgeon do not exhibit the physiological responses to exhaustive exercise typical of other fish species. They may possess behavioural or endocrinological mechanisms that differ from those of other fishes and that lead to a reduced ability to respond physiologically to exhaustive exercise.

Physiological responses to air exposure stress in Siberian sturgeon ( Acipenser baerii Brandt 1869) injected with dexamethasone

“…Hypoxia and exercise stressors can trigger the fish to increase lactate as a result of the anaerobic metabolism (Rodnick & Planas, 2016; Sheng et al, 2019). Lactate levels show different values in fish species after the stress (Brown & Kieffer, 2019; Eslamloo & Falahatkar, 2014; Jafari & Falahatkar, 2019; Kieffer et al, 2001) which is reflected in species‐specific pattern and different methods for measurement (Fanouraki et al, 2011; Kieffer et al, 2001). The results revealed an increase in lactate levels up to 1 h that reflected increase of anaerobic activity of white muscle and metabolic rate through the periods of severe exercise (Pankhurst & Dedualj, 1994).…”

Creatine: A valuable supplement in aquafeeds?

“…In Rainbow trout Oncorhynchus mykiss (Walbaum), a single tail‐flip is sufficient to decrease the phosphocreatine content of white muscle by 50% 21,85 . When fish are exercised to exhaustion for 5 min, muscle phosphocreatine concentration decrease between 50% to near depletion 86–88 . Recovery, however, may be rapid and replenishment was observed within minutes or less than 1 h post‐exercise 86,87 .…”

“…21,85 When fish are exercised to exhaustion for 5 min, muscle phosphocreatine concentration decrease between 50% to near depletion. [86][87][88] Recovery, however, may be rapid and replenishment was observed within minutes or less than 1 h post-exercise. 86,87 When exercised juvenile Rainbow trout were supplemented with creatine, endurance in a fixed velocity test increased.…”

“…[86][87][88] Recovery, however, may be rapid and replenishment was observed within minutes or less than 1 h post-exercise. 86,87 When exercised juvenile Rainbow trout were supplemented with creatine, endurance in a fixed velocity test increased. 89 Exercise itself can increase the amount of phosphocreatine in the muscles as well.…”

The role of salinity in recovery of white sturgeon (Acipenser transmontanus) from stimulated angling stress

“…Although sturgeon demonstrate the capacity to tolerate exhaustive exercise in FW ( Kieffer et al, 2001 ; Baker et al, 2005a ; Shartau et al, 2017 ; Brown and Kieffer, 2019 ; Penny and Kieffer, 2019 ; Kieffer and May, 2020 ), it remains unknown how quickly they are able to restore their acid–base status and it is uncertain if acclimation to higher salinities affects severity of, or recovery from, this challenge. To examine the effect of salinity on exhaustive exercise associated with C&R, we subjected WS to stimulated angling stress (SAS) after acclimation to either 0, 10 or 20‰ and assessed the effects using a suite of physiological indicators.…”