Consequences of Pulsed DC Electrofishing and Air Exposure to Rainbow Trout (Oncorhynchus mykiss)

1994 ◽  
Vol 51 (8) ◽  
pp. 1791-1798 ◽  
Author(s):  
C. J. A. Mitton ◽  
D. G. McDonald
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Additional Stress ◽  
Physical Damage ◽  
Early Recovery ◽  
Air Exposure ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Pulsed Dc ◽  
Fish Collection ◽  
Stimulation Of

Electrofishing, a technique widely used for fish collection, is a procedure that is often followed by handling and air exposure before fish are released. In this study the pathological and physiological consequences of capture with pulsed DC (pDC) electroshock with and without the additional disturbance of air exposure were examined on rainbow trout (Oncorhynchus mykiss). Electroshocked fish showed no evidence of direct mortality, and skeletal damage was only induced under the most severe conditions (~600-g fish, 600 V, 20 or 40 s). Physiological disturbances induced by pDC, in the absence of physical damage, consisted of lactacidosis and stimulation of the interrenal stress response. The acidosis was likely induced by tetany during immobilization and apnea during immobilization and early recovery. In fact, the physiological disturbances induced by pDC were similar in magnitude and duration to 2–3 min of exhaustive exercise and generally more severe than responses previously reported for nonpulsed (i.e., continous) DC gear. In addition, following pDC, fish appeared to experience a mild narcosis, as was evident by a reduced response to the additional stress of air exposure.

Effects of Electroshock, Air Exposure, and Forced Exercise on Swim Performance in Rainbow Trout (Oncorhynchus mykiss)

1994 ◽  
Vol 51 (8) ◽  
pp. 1799-1803 ◽  
Author(s):  
C. J. A. Mitton ◽  
D. G. McDonald
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Intracellular Ph ◽  
Physiological Effects ◽  
Air Exposure ◽  
Swim Performance ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Pulsed Dc ◽  
Identical Fashion

Swim performance of rainbow trout (Oncorhynchus mykiss) following forced exercise and pulsed DC electroshock both with and without subsequent air exposure was examined. Swim stamina was assessed by exercising fish at 39 cm/s until exhausted. Swim performance was impaired following all treatments. Increasing durations of air exposure (0–4 min) after electroshock resulted in progressively prolonged durations of swimming impairment (from 1 to 6 h). Electroshock reduced swimming stamina in a virtually identical fashion to that of 5 min of forced exercise. By comparison with the existing literature on the physiological effects of forced exercise, the impairment of swim performance most likely resulted from a reduction in intracellular pH.

Physiological Effects of Brief Air Exposure in Exhaustively Exercised Rainbow Trout (Oncorhynchus mykiss): Implications for "Catch and Release" Fisheries

1992 ◽  
Vol 49 (6) ◽  
pp. 1157-1162 ◽  
Author(s):  
R. A. Ferguson ◽  
B. L. Tufts
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Blood Gases ◽  
Control Fish ◽  
Additional Stress ◽  
Physiological Effects ◽  
Air Exposure ◽  
Catch And Release ◽  
Extracellular Acidosis ◽  
Rainbow Trout Oncorhynchus Mykiss

Rainbow trout (Oncorhynchus mykiss) which were air exposed for 60 s after exhaustive exercise initially had a much larger extracellular acidosis than trout which were only exercised. In both groups, however, plasma pH returned to normal by 4 h. Blood lactate concentrations were also greater in the air-exposed fish and continued to increase throughout the experiment. During air exposure, there was retention of carbon dioxide in the blood, and oxygen tension (Po2) and hemoglobin:oxygen carriage (Hb:O2) both fell by over 80%. After 30 min of recovery, however, blood gases resembled those in fish which were only exercised. Finally, survival after 12 h was 10% in control fish and 88% in the exercised fish but fell to 62 and 28% in fish which were air exposed for 30 and 60 s, respectively, after exercise. These results indicate that the brief period of air exposure which occurs in many "catch and release" fisheries is a significant additional stress which may ultimately influence whether a released fish survives.

Insulin and insulin-like growth factor I signaling pathways in rainbow trout (Oncorhynchus mykiss) during adipogenesis and their implication in glucose uptake

2010 ◽  
Vol 299 (1) ◽  
pp. R33-R41 ◽  
Author(s):  
L. Bouraoui ◽  
E. Capilla ◽  
J. Gutiérrez ◽  
I. Navarro
Keyword(s):  
Rainbow Trout ◽  
Growth Factor ◽  
Oncorhynchus Mykiss ◽  
Glucose Uptake ◽  
Signaling Pathways ◽  
Mapk Phosphorylation ◽  
Factor I ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Igf I ◽  
Stimulation Of

Primary cultures of rainbow trout ( Oncorhynchus mykiss ) adipocytes were used to examine the main signaling pathways of insulin and insulin-like growth factor I (IGF-I) during adipogenesis. We first determined the presence of IGF-I receptors (IGF-IR) and insulin receptors (IR) in trout preadipocytes ( day 5) and adipocytes ( day 14). IGF-IRs were more abundant and appeared to be in higher levels in differentiated cells than in preadipocytes, whereas IRs were detected in lower but constant levels throughout the culture. The cells were immunoreactive against ERK1/2 MAPK, and AKT/PI3K, components of the two main signal transduction pathways for insulin and IGF-I receptors. Stimulation of MAPK phosphorylation by IGF-I was higher in preadipocytes than in adipocytes, while no effects were observed in MAPK phosphorylation after incubation of cells with insulin. AKT phosphorylation increased in the presence of both insulin and IGF-I, with higher levels of stimulation in adipocytes than in preadipocytes. Activation of both pathways was blocked by the use of specific inhibitors of MAPK (PD98059) and AKT (wortmannin). We describe here, for the first time, the effects of IGF-I and insulin on 2-deoxyglucose uptake in primary culture of trout adipocytes. IGF-I was more potent in stimulating glucose uptake than insulin, and PD98059 and wortmannin inhibited the stimulation of glucose uptake by this growth factor, suggesting that IGF-I plays an important metabolic role in trout adipocytes. Our results suggest that differential activation of the MAPK and AKT pathways are involved in the IGF-I- and insulin-induced effects of trout adipocytes during the various stages of adipogenesis.

Suspended sediment pulse effects in rainbow trout (Oncorhynchus mykiss) — relating apical and systemic responses

2013 ◽  
Vol 70 (4) ◽  
pp. 630-641 ◽  
Author(s):  
Christian Michel ◽  
Heike Schmidt-Posthaus ◽  
Patricia Burkhardt-Holm
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Condition Factor ◽  
Mineral Particle ◽  
Physical Damage ◽  
Tubular Cells ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Metabolic Adaptations ◽  
Systemic Responses ◽  
Somatic Index

To provide an integrated perspective on mineral particle effects in salmonids, juvenile rainbow trout (Oncorhynchus mykiss) were exposed to daily mica particle pulses for 8 and 24 days. On day 8, increased immature erythrocyte proportions indicated a previous stress response. This response was absent on day 24, on which condition factor as well as plasma protein and aspartate aminotransferase activity decreased. The latter two related negatively to the hepato-somatic index, suggesting metabolic adaptations. The hepato-somatic index increased on days 8 and 24, while spleen-somatic index increased on day 24. No histopathological damage occurred in gills, liver, spleen, or kidney. However, splenic melano-macrophages increased on both days, and hyaline degenerations of kidney tubular cells were apparent on day 24. Overall, particle pulses affected rainbow trout more via turbidity rather than by physical damage. We conclude that (i) rainbow trout may adapt to sediment pulses as early as 8 days of exposure and (ii) particle pulses over 24 days can cause structural and metabolic changes in rainbow trout, even when gill damage is absent and apical effects on condition are moderate.

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