Altered burst swimming in rainbow trout Oncorhynchus mykiss exposed to natural and synthetic oestrogens

Abstract

Juvenile rainbow trout Oncorhynchus mykiss were exposed to two concentrations each of 17β-oestradiol (E2; natural oestrogen hormone) or 17α-ethinyl oestradiol (EE2; a potent synthetic oestrogen hormone) to evaluate their potential effects on burst-swimming performance. In each of six successive burst-swimming assays, burst-swimming speed (Uburst ) was lower in fish exposed to 0.5 and 1 µg l(-1) E2 and EE2 for four days compared with control fish. A practice swim (2 days prior to exposure initiation) in control fish elevated initial Uburst values, but this training effect was not evident in the 1 µg l(-1) EE2-exposed fish. Several potential oestrogen-mediated mechanisms for Uburst reductions were investigated, including effects on metabolic products, osmoregulation and blood oxygen-carrying capacity. Prior to burst-swimming trials, fish exposed to E2 and EE2 for 4 days had significantly reduced erythrocyte numbers and lower plasma glucose concentrations. After six repeated burst-swimming trials, plasma glucose, lactate and creatinine concentrations were not significantly different among treatment groups; however, plasma Cl(-) concentrations were significantly reduced in E2- and EE2-treated fish. In summary, E2 and EE2 exposure altered oxygen-carrying capacity ([erythrocytes]) and an osmoregulatory-related variable ([Cl(-) ]), effects that may underlie reductions in burst-swimming speed, which will have implications for fish performance in the wild.

Differences in swimming ability and its response to starvation among male and femaleGambusia affinis

“…U crit is commonly known to participate in the aerobic exercises such as cruising and finding mates (Langerhans, 2009; Sinclair et al, 2011), whereas U burst is involved during fast movement such as escaping from predator and catching preys, which is crucial for survival (Osachoff et al, 2014). Male G .…”

“…A previous study demonstrated that the amounts of PCr in muscles are stable and the storage amounts did not significantly decline after starvation (Kieffer and Tufts, 1998), which could be ascribed to stable U burst than U crit after starvation. Due to the involvement in escaping from the predators, catching prey, or passing through rapids riffles (Kieffer, 2000; Osachoff et al, 2014), U burst may be more important than U crit for survival in most fishes. Therefore, we speculate that male and female G .…”

“…The speed of swimming of fish is primarily categorized into burst swimming speed ( U burst ) and critical swimming speed ( U crit ) according to the levels of oxygen demand. Burst swimming is powered anaerobically by white muscle and is considered as the highest speed; however, it is used only for a short period (<15 or 20 s), especially while escaping from predators, catching the prey, and passing rapids, riffles, and fishways (Kieffer, 2000; Osachoff et al, 2014; Yeh et al, 2010). Critical swimming is driven by aerobic conditions using the red muscle for a prolonged period without fatigue (Brett, 1972).…”

Lethal and sublethal effects in Pink salmon (Oncorhynchus gorbuscha) following exposure to five aquaculture chemotherapeutants

“…Fish were removed, euthanized with MS 222 and wet weight (g) and fork length (cm) measured. Critical swimming speed (Ucrit) was calculated as the maximum speed attained by each sh normalized to fork length (BL/s [Osachoff et al, 2014]). The cross-sectional area of all swim-tested sh were less than 10% of swim tunnel cross-sectional area and sh density were under 0.2 g/L, therefore no correction for a solid blocking effect was needed (Webb, 1971).…”

Sustained Swimming Training Is Associated With Reversible Filet Texture Changes of European Sea Bass (Dicentrarchus labrax L.)

“…Swimming is an important aspect of the life history of most teleost fish species in aquatic environments. Teleost fish have a great capacity for both sustained (Magnoni et al, 2013; Palstra et al, 2015) and burst swimming (Tudorache et al, 2010; Osachoff et al, 2014), and high water velocities promote the growth and feed conversion efficiency of these fish (Jobling et al, 1993; Davison, 1997). This effect of high water velocity (and sustained swimming under these conditions) is believed to be the result of hyperplasia (the growth of new small fibers) and hypertrophy (the growth of existing fibers) (Li et al, 2016).…”