Nature and Time Course of Acclimation to Aluminum in Juvenile Brook Trout (Salvelinus fontinalis). II. Gill Histology

1991 ◽  
Vol 48 (10) ◽  
pp. 2016-2027 ◽  
Author(s):  
M. E. Mueller ◽  
D. A. Sanchez ◽  
H. L. Bergman ◽  
D. G. McDonald ◽  
R. G. Rhem ◽  
...  
Keyword(s):  
Brook Trout ◽  
Time Course ◽  
Salvelinus Fontinalis ◽  
Mucous Cell ◽  
Volume Density ◽  
Cellular Level ◽  
Control Fish ◽  
Mortality Data ◽  
Mucous Cells ◽  
Exposed Fish

Gill samples from juvenile brook trout (Salvelinus fontinalis) acclimated to low-level aluminum at pH 5.2 showed severe damage by day 4, with necrosis and fusion of secondary lamellae and hyperplasia and hypertrophy of mucous cells. Over the following 20 d, there was a continual process of repair with proliferation and hypertrophy of mucous cells. Qualitative analysis of gill samples plus physiology and mortality data collected in a companion study indicated progressive development (by day 10 onward) of increasing acclimation to Al. Quantitative analysis of gill samples on day 13 showed that mucous cell volume density had tripled and mucous cell area had doubled in Al-exposed fish compared with control fish. A lamellar fusion index showed evidence of fusion in Al-exposed fish by day 4 with recovery to nearly control levels by day 13. Physiological disturbances appear to be directly related to the histological changes observed in the gill epithelium. At the cellular level, changes in either mucous cell production and secretion or changes in mucus chemistry contribute, in part, to acclimation to Al.

Experimental Plantings of Brook Trout (Salvelinus fontinalis) from Furunculosis-Infected Stock

1968 ◽  
Vol 25 (12) ◽  
pp. 2643-2649 ◽  
Author(s):  
L. A. McDermott ◽  
A. H. Berst
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Infected Fish ◽  
Aeromonas Salmonicida ◽  
Control Fish ◽  
Southern Ontario ◽  
Trout Population ◽  
Hatchery Stock ◽  
Associated Species ◽  
Made In

Preliminary sampling revealed the presence of furunculosis disease in the resident brook trout population of the southern Ontario trout stream used in this study.Two plantings of marked yearling brook trout were made in the study area in 1966; one in the spring, and the other in the fall. The spring planting consisted of 1000 brook trout with a predetermined incidence of furunculosis infection and an equal number of trout with no evidence of infection. The fall planting consisted of 2000 brook trout with a known incidence of furunculosis infection.The stream was electrofished periodically during the 2-year period after the first planting. A total of 445 brook trout (140 of the planted hatchery stock, and 305 resident trout) and 127 fish of associated species were captured and examined for the presence of Aeromonas salmonicida, causative agent of furunculosis.Recovery rates of the "infected" and "noninfected" stocks of brook trout were similar, and there was no evidence of transmission of A. salmonicida from the infected fish to the control fish, nor the resident population of brook trout and other species of fish captured.

Retardation and Recovery of Growth in Brook Trout Fry (Salvelinus fontinalis) Exposed for Various Durations to Acidified Water

1986 ◽  
Vol 43 (10) ◽  
pp. 2048-2050 ◽  
Author(s):  
W. H. Tam ◽  
P. D. Payson ◽  
R. J. J. Roy
Keyword(s):  
Growth Inhibition ◽  
Growth Rates ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Low Ph ◽  
Fish Growth ◽  
Control Fish ◽  
Treated Fish ◽  
Test Fish ◽  
Neutral Water

Brook trout fry (Salvelinus fontinalis) were exposed to pH 4.66 for various durations up to 141 d and then returned to neutral water. Growth of test fish was in general significantly lower than that of control fish for exposures up to days 45–78. In four of six groups of acid-treated fish, growth eventually recovered and the growth rates were not different from that of control fish. The results suggested that growth inhibition was induced early in the exposure to sublethally low pH and that recovery in the latter phase of the experiment occurred whether pH remained acidic or was readjusted to neutral.

Growth and Resistance to Stress in Brook Trout Fed Sublethal Levels of DDT

1968 ◽  
Vol 25 (11) ◽  
pp. 2443-2451 ◽  
Author(s):  
Kenneth J. Macek
Keyword(s):  
Weight Gain ◽  
Water Temperature ◽  
Brook Trout ◽  
Feeding Rate ◽  
Salvelinus Fontinalis ◽  
Physiological Stress ◽  
Environmental Stresses ◽  
Exposed Fish ◽  
Cumulative Mortality ◽  
Resistance To Stress

When underyearling brook trout (Salvelinus fontinalis) were fed DDT at a rate of 2.0 mg/kg per week for 31 weeks, they exhibited greater weight gain (43.2 ± 0.8 g) during the period than did untreated fish (36.6 ± 1.1 g). When underyearling fish were fed DDT at different rates for 26 weeks and then starved or fed at a rate equivalent to 10% of the usual feeding rate, the cumulative mortality during this period was 96.2% among fish exposed to 3.0 mg/kg per week, 88.6% among fish exposed to 2.0 mg/kg per week, and 1.2% among untreated fish. Differences in the length of survival of DDT-exposed fish occurred due to dosage, sex, and type of starvation. The evidence suggests that the mortality of DDT-exposed fish was due to the interaction of DDT residues with a combination of environmental stresses, namely starvation, decreasing water temperature, and possibly the physiological stress associated with the spawning season.

Effects of Aluminum and Low pH on Net Ion Fluxes and Ion Balance in the Brook Trout (Salvelinus fontinalis)

1988 ◽  
Vol 45 (9) ◽  
pp. 1563-1574 ◽  
Author(s):  
C. E. Booth ◽  
D. G. McDonald ◽  
B. P. Simons ◽  
C. M. Wood
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Inhibitory Effect ◽  
Low Ph ◽  
Exposed Fish ◽  
Water Ph ◽  
In The Wild ◽  
Ph Dependent ◽  
Total Body ◽  
Stimulation Of

Adult brook trout (Salvelinus fontinalis) were exposed for up to 11 d to one of a matrix of 18 Al, low pH, and Ca2+ combinations, chosen as representive of acidified softwater environments in the wild. Reduction in water pH led to pH-dependent net losses of Na+ and Cl− exacerbated by the presence of Al in the water and reduced by elevating Ca2+. Any animal losing more than 4% of its total body Na+ over the first 24 h of Al exposure had a greater than 90% likelihood of eventual mortality. Na+ losses arose from inhibition of influx and stimulation of efflux. The inhibition was persistent and pH dependent. Addition of Al to acidified water had a slight further inhibitory effect on Na+ influx and a large stimulatory effect on efflux. The latter was dependent on Al concentration, was the main cause of initial ion losses and mortality, and declined with time in surviving animals. All Al-exposed fish accumulated Al on their gills, but this was apparently mainly surface or subsurface bound, since no internal Al (plasma or liver) could be detected. Nonsurviving fish had substantially higher gill Al levels than survivors.

The development and maturation of vitellogenic oocytes, plasma steroid hormone levels, and gonadotrope activities in acid-stressed brook trout (Salvelinus fontinalis)

1996 ◽  
Vol 74 (4) ◽  
pp. 587-593 ◽  
Author(s):  
W. H. Tam ◽  
Xiaomin Zhang
Keyword(s):  
Food Intake ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Ph Control ◽  
Oocyte Development ◽  
Control Fish ◽  
Control Group ◽  
Food Control ◽  
Neutral Ph ◽  
Sequence Of Events

Brook trout (Salvelinus fontinalis) were divided into a control group at neutral pH, a food-restricted control (Ph–food control) group at neutral pH, and an acid-stressed (pH 4.15) group, and were maintained under these conditions from August 14 to November 1. The food for the pH–food control group was restricted to simulate the reduced food intake of the acid-stressed fish. Throughout September, oocyte development in the acid-stressed fish was accelerated and the oocytes weighed 36–54% more than those of the pH control fish. By late September these oocytes had reached ovulatory size. Then a shift from predominantly high estrogen to high 17α,20β-dihydroxy-4-pregnen-3-one levels occurred in the circulation. Ovulation followed and by October 19 all acid-stressed trout had ovulated. The same sequence of events occurred significantly later in the pH control fish and ovulation was not complete on November 1. Although their oocytes were larger than those of pH control fish in September, hormonal changes and ovulation in pH–food control fish occurred at the same time as in pH control fish. The results suggest that while the reduced food intake during acid stress might have contributed to accelerated oocyte growth, the full effect of chronic acid exposure was responsible for advancing oocyte development, maturation, and ovulation.

Nature and Time Course of Acclimation to Aluminum in Juvenile Brook Trout (Salvelinus fontinalis). I. Physiology

1991 ◽  
Vol 48 (10) ◽  
pp. 2006-2015 ◽  
Author(s):  
D. G. McDonald ◽  
C. M. Wood ◽  
R. G. Rhem ◽  
M. E. Mueller ◽  
D. R. Mount ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Acid Content ◽  
Brook Trout ◽  
Time Course ◽  
Salvelinus Fontinalis ◽  
Sialic Acid Content ◽  
Progressive Development ◽  
The Face ◽  
Physiological Impact ◽  
Lactate Levels

Chronic exposure (up to 42 d) of juvenile brook trout (Salvelinus fontinalis) to sublethal aluminum at pH 5.2 resulted in a damage/repair acclimation phenomenon. The damage developed rapidly (within 24 h), was centered at the gills, and was characterized by substantial accumulation of Al, a corresponding reduction of gill sialic acid content (a measure of gill mucus), and inhibition of branchial Na+ transport. The corresponding internal effects of this initial damage were losses of electrolytes, hemoconcentration, and impaired tissue O2 delivery (as indicated by elevated lactate). Repair was characterized by progressive reduction of gill Al, restoration of sialic acid content, recovery of Na+ transport, and reduction in hemoconcentration and lactate levels. Accompanying the recovery was progressive development (by day 10 onwards) of increased resistance (i.e. acclimation) to acutely lethal Al. This acclimation was characterized by a reduction in both the rate of mortality and in the magnitude of physiological disturbances relative to control (i.e. Al naive) fish. The increased short-term resistance translated to greatly improved survivorship and correspondingly diminished physiological impact in the face of chronically elevated Al levels (2 wk at < 300 μg Al/L). The acclimation process clearly resulted from specific changes at the gills.

Epidermal responses of chum salmon (Oncorhynchus keta) fry to the ectoparasitic flagellate Ichthyobodo necator

1992 ◽  
Vol 70 (8) ◽  
pp. 1567-1575 ◽  
Author(s):  
Shigehiko Urawa
Keyword(s):  
Parasite Density ◽  
Chum Salmon ◽  
Periodic Acid ◽  
Mucous Cell ◽  
Major Constituent ◽  
Control Fish ◽  
Oncorhynchus Keta ◽  
Staining Procedure ◽  
Mucous Cells ◽  
Cell Secretion

The numbers of the ectoparasitic flagellate Ichthyobodo necator on chum salmon fry (Oncorhynchus keta) and the host's epidermal responses to infection were monitored for 15 weeks with light and scanning electron microscopy. Parasite density on the skin peaked at 3 weeks postinfection, at an average of 625 parasites/mm2, and then decreased to near zero by week 10. The staining procedure with Alcian blue (AB, pH 2.5) and periodic acid – Schiffs reagent (PAS) revealed dramatic changes in both the degree and histochemistry of epidermal mucus secretion during the course of the parasite infections. The numbers of mucous cells declined significantly during the first 4 weeks as parasite density increased, but thereafter rose to 2000 cells/mm2 by week 8, when mucous cells stained with PAS alone predominated. This increase occurred concomitantly with a reduction in parasite density. In the control fish, the concentration of epidermal mucous cells was stable at 400 – 800 cells/mm2 during the same period and acid mucopolysaccharides (PAS-negative, AB-positive) were a major constituent of the mucous cell secretion. It is suspected that the PAS-positive mucous cells may play an important role in the defence mechanism against the parasite infection.

Effects of Long-Term Preexposure to Sublethal Concentrations of Acid and Aluminum on the Ventilatory Response to Aluminum Challenge in Brook Trout (Salvelinus fontinalis)

1991 ◽  
Vol 48 (10) ◽  
pp. 1989-1995 ◽  
Author(s):  
R. L. Walker ◽  
C. M. Wood ◽  
H. L. Bergman
Keyword(s):  
Stroke Volume ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Ventilatory Response ◽  
Lethal Dose ◽  
Control Fish ◽  
Twofold Increase ◽  
Arterial Ph ◽  
Sublethal Concentrations

Adult brook trout (Salvelinus fontinalis; 200–300 g) were preexposed for 10 wk to 75 μg Al3+∙L−1, pH = 5.2, in soft water (25 μequiv Ca2+∙L−1) and controls to the same conditions without Al3+. When challenged with a lethal dose of Al3+ (333 μg∙L−1) at the same pH (5.2) and Ca2+ (25 μequiv∙L−1), the control fish demonstrated a twofold increase in ventilation volume and ventilatory stroke volume within the first two hours, an increase in [Formula: see text], and a decrease in pHa and hemoglobin O2 saturation. These effects were not seen in the group chronically preexposed to sublethal Al, indicating that some acclimation had occurred. Although the prechallenge [Formula: see text] and [Formula: see text] were the same in the two groups, the arterial pH, plasma [HCO3−], and hemoglobin O2 saturation of the Al-preexposed fish were significantly below those of the control fish, suggesting that the acclimation was achieved at some cost. Possible mechanisms are discussed.

Influence of Fenitrothion on Swimming Velocities of Brook Trout (Salvelinus fontinalis)

1974 ◽  
Vol 31 (11) ◽  
pp. 1757-1762 ◽  
Author(s):  
R. H. Peterson
Keyword(s):  
Critical Velocity ◽  
Swimming Speed ◽  
Power Output ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Sublethal Effects ◽  
Step Test ◽  
Control Fish ◽  
Test Interval

The critical swimming velocities of brook trout (Salvelinus fontinalis) following exposure to 150, 500, and 1500 μg/liter fenitrothion were 100, 83, and 70%, respectively, of the performance of control fish. This represented 35 and 60% decrease in power output, respectively, for the two higher concentrations.At step-test intervals longer than 15 min, the critical velocity (ca 4.5–5 lengths [L]/s) was reasonably constant. At shorter step-test intervals, the critical velocity increased rapidly to exceed 7 L/s at a step-test interval of 30 s. The cruising speed of control fish was estimated at 4.5 L/s.The influence of fenitrothion exposure on swimming speed is related to previous studies on sublethal effects of fenitrothion and to concentrations in streams resulting from insecticide spraying.

Morphometric Changes in Gill Secondary Lamellae of Brook Trou (Salvelinus fontinalis) After Long-Term Exposure to Acid and Aluminum

1988 ◽  
Vol 45 (9) ◽  
pp. 1643-1648 ◽  
Author(s):  
J. E. Tietge ◽  
R. D. Johnson ◽  
H. L Bergman
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Gill Tissue ◽  
Volume Density ◽  
Low Ph ◽  
Chloride Cells ◽  
Physiological Data ◽  
Secondary Lamellae ◽  
Respiratory Efficiency

Adult brook trout (Salvelinus fontinalis) were exposed for 147 d to three different combinations of acid and Al in soft water (2 mg Ca/L). Samples of gill tissue from each of the three exposure conditions (pH 6.64 + 0 μg Al/L, pH 4.91 + 4.3 μg Al/L, and pH 4.45 + 393 μg Al/L) were examined by light microscopy using high-resolution techniques and morphometric analysis. As compared with fish in control conditions (pH 6.64 + 0 μg Al/L), exposure to pH 4.91 without Al significantly increased volume density of lamellar chloride cells. Low pH and elevated Al (pH 4.45 + 393 μg Al/L) resulted in increased diffusion distance, white blood cell infiltration of the lymphatic space of the gill tissue (an indicator of tissue damage), and a dramatic increase in lamellar dense cells. These results are consistent with the physiological data that show ionoregulatory stress and decreased respiratory efficiency as typical responses of brook trout exposed to low pH and combinations of low pH and elevated Al.

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