Morphological changes in rainbow trout (Oncorhynchus mykiss) gill epithelia following repeated intermittent exposure to chloramine-T

1995 ◽  
Vol 73 (1) ◽  
pp. 154-165 ◽  
Author(s):  
Mark D. Powell ◽  
David J. Speare ◽  
Glenda M. Wright
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Morphological Changes ◽  
Experimental Period ◽  
Chloride Cells ◽  
Compensatory Mechanism ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Freshwater Aquaculture ◽  
Intermittent Exposure ◽  
Chloramine T

Chloramine-T is a widely used prophylactic and therapeutic agent in freshwater aquaculture. This study examined the effects of repeated intermittent exposure of healthy rainbow trout (Oncorhynchus mykiss) fingerlings to sublethal concentrations of chloramine-T (0, 5, 10, or 20 mg/L) twice weekly in 1-h pulses at 11 °C for 4 weeks in a replicate-tank facility. Gills were excised from subsamples of fish prior to exposure and at the end of the 4-week experimental period. Tissue was fixed and processed for light microscopy and transmission and scanning electron microscopy. The gill epithelium from fish treated with 10 and 20 mg/L chloramine-T appeared swollen and vacuolated, with extensive intercellular edema. There was a significant reduction in the number of lamellar mucous cells and an apparent increase in the numbers of chloride cells. Chloride cells from both the base of the lamella and the lamellar surface of gills exposed to chloramine-T had a significant increase in the area of the apical plasmalemma after treatment with 10 and 20 mg/L, and a reduction in the thickness of the apical plasmalemma-associated glycocalyx. These morphological changes are consistent with a compensatory mechanism for the remedial uptake of ions, suggesting that chloramine-T increased epithelial ion permeability coincident with a possible influx of water leading to intercellular edema. Chloride cell proliferation and intercellular edema may also have affected gas exchange across the branchial epithelium.

Shortening of Branchial Tight Junction Acid-Exposed Rainbow Trout (Oncorhynchus mykiss)

1991 ◽  
Vol 48 (10) ◽  
pp. 2028-2033 ◽  
Author(s):  
J. Freda ◽  
D. A. Sanchez ◽  
H. L. Bergman
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Tight Junctions ◽  
Relative Magnitude ◽  
Chloride Cells ◽  
Pavement Cells ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Plasma Electrolytes ◽  
Gill Structure ◽  
Electrolyte Loss

The objective of this study was to investigate possible sites for Na+ loss in fish exposed to low environmental pH. In rainbow trout (Oncorhynchus mykiss) exposed to pH 4.0 for 1 h, a net loss of Na+ was stimulated, and changes in gill structure occurred. In addition to epithelial lifting and necrosis in the gills of acid-exposed fish, tight junctions between pavement epithelial cells and chloride cells decreased in length by 25% whereas tight junctions between adjacent pavement cells did not significantly change. In a second experiment where fish were moved from pH 4.0 or 3.5 water to pH 6.5 water, we observed that Na+ loss declined immediately and approached control levels. The reversible nature of the stimulation of Na+ loss indicates that the site of Na+ loss in the fish gill can be reversibly opened and closed, which is consistent with the known properties of tight junctions. We hypothesize that the opening of tight junctions contributes to the loss of plasma electrolytes at low environmental pH. However, the relative magnitude of electrolyte loss through the tight junctions remains unknown.

Effects of Intermittent Chloramine-T Exposure on Growth, Serum Biochemistry, and Fin Condition of Juvenile Rainbow Trout (Oncorhynchus mykiss)

1994 ◽  
Vol 51 (8) ◽  
pp. 1728-1736 ◽  
Author(s):  
Mark D. Powell ◽  
David J. Speare ◽  
Neil MacNair
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Skin Diseases ◽  
Growth Parameters ◽  
Serum Biochemistry ◽  
Control Fish ◽  
Plasma Sodium ◽  
Juvenile Rainbow Trout ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Chloramine T

Chloramine-T is a commonly used therapeutic agent for the treatment of bacterial gill and skin diseases in the intensive aquaculture of salmonids; however, little is known about its effects on healthy fish. Juvenile rainbow trout (Oncorhynchus mykiss) were exposed weekly to 5, 10, and 20 mg active chloramine-T ingredient∙L−1 in a 20-tank replicate flow-through facility. Control fish were treated with tank water only. Growth parameters and haematocrits were taken twice weekly and serum biochemistry was measured on termination of the experiment. Absolute growth rates were suppressed but only statistically significantly in fish treated with 20 mg chloramine-T∙L−1 compared with controls. Fish exposed to 10 and 20 mg chloramine-T∙L−1 showed significant predisposition to an erosive dermatitis of the caudal fin which appeared to be caused by opportunistic pathogens of the genus Pseudomonas spp. and Flavobacter spp. Haematocrits decreased in controls and ail treatments. A significant concentration-dependent decrease in plasma sodium and chloride was observed. Plasma glucose levels did not vary and were similar to those reported for unstressed trout. We recommend that care be taken when using chloramine-T prophylactically and that concentrations of less than 10 mg∙L−1 be used.

Branchial Morphological and Endocrine Responses of Rainbow Trout (Oncorhynchus mykiss) to a Long-Term Sublethal Acid Exposure In Which Acclimation Did Not Occur

1993 ◽  
Vol 50 (1) ◽  
pp. 198-209 ◽  
Author(s):  
Céline Audet ◽  
Chris M. Wood
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Chloride Cell ◽  
Chloride Cells ◽  
Physiological Data ◽  
Mucous Cells ◽  
Diffusion Distance ◽  
Cell Numbers ◽  
Rainbow Trout Oncorhynchus Mykiss

Changes in branchial morphology and in plasma Cortisol, adrenaline, and noradrenaline were quantified throughout an 81 -d exposure of rainbow trout (Oncorhynchus mykiss) to sublethal acidity (pH 4.8) in artificial soft water and after a 5-h acid challenge (pH 4.0) of naive fish and 81-d acid-preexposed fish. Changes in branchial morphology at pH 4.8 were generally very mild and characterized by slight increases in filamental mucous cells and decreases in lamellar mucous cells. Chloride cell numbers and branchial Na+–K+- and total ATPase activities did not change. The filamental epithelium thickened, but the water–blood diffusion distance in the lamellae decreased during chronic exposure. Cortisol was significantly elevated throughout whereas catecholamines exhibited relatively little response. Response to acute pH 4.0 challenge was similar in naive and 81-d acid-exposed fish: epithelial damage, increase in visible mucous cells, loss of chloride cells by necrosis, and high cortisol levels but no changes in lamellar or filamental epithelial thickness, diffusion distance, ATPase activities, or catecholamine levels. Previously reported physiological data from these same trout demonstrated that sensitization rather than acclimation had occurred. Therefore, these observations support the view that acclimation does not occur in the absence of significant branchial damage and repair.

Proton Transport and Chloride Cells in the Gill of Rainbow Trout (Oncorhynchus mykiss)

1993 ◽  
Vol 50 (5) ◽  
pp. 988-995 ◽  
Author(s):  
Nils Petter Berg Justesen ◽  
Torbjørn Dall-Larsen ◽  
Leiv Klungsøyr
Keyword(s):  
Carbon Dioxide ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Proton Transport ◽  
External Medium ◽  
Control Fish ◽  
Chloride Cells ◽  
Submitochondrial Particles ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Trout Gill

Particulate preparations from freshwater rainbow trout (Oncorhynchus mykiss) gill homogenates contain an active magnesium ion activated ATPase that transports protons into the vesicles. Oligomycin at a concentration of 20 μg∙mL−1 had little effect on the proton transport, which was completely inhibited by N-ethylmaleimide. This inhibition was partly counteracted by dithiothreitol. Proton transport in freshwater trout gill submitochondrial particles was completely inhibited by oligomycin. When freshwater trout were kept for 40 min in water equilibrated with air containing 5% carbon dioxide, their gill lamellar epithelium contained many cells densely covered with erect microvilli. After changing to water bubbled with room air, the cells rapidly lost their microvilli. Control fish that were killed immediately after removal from the storage tank also had microvilli, but less erect and fewer in number. Labelled latex microspheres and dextran were used as markers for external medium uptake into gill epithelial cells. The fish were pretreated by bubbling the water by air containing 5% carbon dioxide, and the uptake took place when the water was bubbled with room air.

Acclimation of Rainbow Trout (Oncorhynchus mykiss) to Low Environmental pH Does Not Involve an Activation of the Pituitary-interrenal Axis, but Evokes Adjustments in Branchial Ultrastructure

1993 ◽  
Vol 50 (12) ◽  
pp. 2532-2541 ◽  
Author(s):  
P. H. M. Balm ◽  
T. G. Pottinger
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Acid Stress ◽  
Ultrastructural Changes ◽  
Control Fish ◽  
Chloride Cells ◽  
Additional Stress ◽  
Exposed Fish ◽  
Rainbow Trout Oncorhynchus Mykiss

Two strains of rainbow trout (Oncorhynchus mykiss) were exposed to soft water at pH 4.0 for 14 days, after ambient pH was reduced gradually. Several parameters, either indicators of acid stress, or reportedly involved in the adaptive response to low pH, were monitored. No mortality occurred during the exposure period; feeding behavior, haematocrit, and plasma protein levels were not affected. A transient depression of leucocrit was observed. A minor, but significant, hypochloremia and perturbations in plasma glucose levels occurred in acid-exposed fish from one strain only. There was no evidence of activation of the pituitary-interrenal axis in acid-exposed fish. Baseline plasma ACTH and Cortisol levels were indistinguishable from those of control fish, and there was no evidence of sensitization to additional stress in acid-exposed fish, in vitro baseline and ACTH-stimulated Cortisol secretion was not significantly different in the two groups. Ultrastructural evidence indicated an increased turnover rate of chloride cells and leucocyte infiltration in gills of acid-exposed fish. These results suggest that interrenal activation and catastrophic ion loss are not inevitable consequences of exposure of rainbow trout to pH 4.0 and that ultrastructural changes in the gills indicate locally regulated adaptive mechanisms.

Effects of an experimental rainbow trout (Oncorhynchus mykiss) farm on invertebrate community compositionThis paper is part of the series “Forty Years of Aquatic Research at the Experimental Lakes Area”.

2009 ◽  
Vol 66 (11) ◽  
pp. 1949-1964 ◽  
Author(s):  
Rebecca C. Rooney ◽  
Cheryl L. Podemski
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Rank Correlation ◽  
Organic Loading ◽  
Experimental Lakes Area ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Northwestern Ontario ◽  
Freshwater Aquaculture ◽  
Invertebrate Abundance ◽  
Production Cycles

We examined the development of changes in the zoobenthos along a transect from an experimental rainbow trout ( Oncorhynchus mykiss ) farm in Lake 375, Experimental Lakes Area, northwestern Ontario, Canada. After 2 months, invertebrate abundance was reduced under the fish cage (2542 ± 569 individuals·m–2) compared with samples collected 45 m away (16 137 ± 2624 individuals·m–2). Taxa richness was also depressed, but changes in biomass were variable. Reductions in abundance and richness at high organic loading levels are consistent with earlier models developed for the marine environment of responses to organic loading in marine systems. After two production cycles, the significant principal components axis explaining 76% of total variance in abundance was correlated with distance from the cage (Spearman rank correlation, r = –0.775, p = 0.014) and with chemical variables recommended for freshwater aquaculture monitoring (Pearson’s correlation coefficient, r = 0.78, 0.76, and 0.75 with p = 0.013, 0.018, and 0.020 for pore-water ammonia and sediment Cu and Zn, respectively). The effects of farming were localized, dissipating within 15 m of the cage edge. Invertebrate abundance demonstrated the most potential for incorporation into monitoring schemes at new farms. At established farms, richness may be a valuable monitoring metric.

The response of zooplankton in a whole-lake experiment on the effects of a cage aquaculture operation for rainbow trout (Oncorhynchus mykiss)

2010 ◽  
Vol 67 (11) ◽  
pp. 1852-1861 ◽  
Author(s):  
Michael J. Paterson ◽  
Cheryl L. Podemski ◽  
Wilhelmina J. Findlay ◽  
David L. Findlay ◽  
Alex G. Salki
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Egg Production ◽  
Crustacean Zooplankton ◽  
Zooplankton Community Structure ◽  
Ecosystem Impacts ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Freshwater Aquaculture ◽  
Multiple Variables ◽  
Cage Aquaculture

There is hope that increased development of aquaculture will help meet future global needs for protein. The growth of the freshwater aquaculture industry in Canada, however, has been hampered by insufficient information on environmental impacts. We examined the effects of an experimental cage aquaculture operation for rainbow trout ( Oncorhynchus mykiss ) on planktonic Crustacea and rotifers using 6 years of precage and 7 years of postcage data. Following the initiation of aquaculture, total crustacean and rotifer biomass, egg production, and depth distributions did not change significantly when compared with data from three nearby unimpacted lakes. We found statistically detectable increases in densities of Bosmina  cf.  longirostris and Diacyclops thomasi and an overall change in crustacean zooplankton community structure using correspondence analysis. The response of zooplankton was less than we expected because comparatively large changes were observed in phytoplankton biomass, hypolimnetic O2, and densities of invertebrate ( Mysis diluviana ) and fish predators. Our study emphasizes the need to monitor multiple variables when assessing the ecosystem impacts of potential stressors such as aquaculture.

Sign in / Sign up

Export Citation Format

Share Document