Growth Inhibition, Gluconeogenesis, and Morphometric Studies of the Pituitary and Interrenal Cells of Acid-Stressed Brook Trout (Salvelinus fontinalis)

1988 ◽  
Vol 45 (7) ◽  
pp. 1197-1211 ◽  
Author(s):  
W. H. Tam ◽  
J. N. Fryer ◽  
I. Ali ◽  
M. R. Dallaire ◽  
B. Valentine
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Hormone Secretion ◽  
Acid Stress ◽  
Somatic Growth ◽  
Experimental Period ◽  
Plasma Cortisol Level ◽  
Electron Microscopic ◽  
Cell Hyperplasia ◽  
Plasma Protein Concentration

Somatic growth was stunted in yearling brook trout (Salvelinus fontinalis) maintained for up to 73 d in pH 4.5. Plasma cortisol level increased in pulses after 1.5 h (from 10 to 82.3 ng∙mL−1) on days 4 (46 ng∙mL−1) and 15–30 (20–25 ng∙mL−1) of acid treatment. Interrenal nuclear hypertrophy and cell hyperplasia occurred respectively on days 4 and 15. Electron microscopic observations revealed that the somatotropes and thyrotropes were atrophic for about half of the experimental period whereas the corticotropes displayed sustained hypertrophy. Plasma glucose and amino acid levels rose simultaneously by 300–600 and 130%, respectively, from day 4 of acid exposure. Hepatic L-alanine aminotransferase activity increased on day 30 just as plasma protein concentration began to decline. When adrenalin and cortisol acetate were administered to trout maintained in neutral pH to raise circulating cortisol levels from 10–20 to 1876 ng∙mL−1, blood glucose remained normal up to 6 d after treatment. These results suggested that acid stress suppressed somatotropin, thyrotropin, and indirectly thyroid hormone secretion but stimulated the pituitary–interrenal axis, leading to inhibition of protein synthesis and accumulation of amino acids in the circulation. The elevation of blood sugar level was caused by some as yet unidentified factors.

Modification of Carbohydrate Metabolism and Liver Vitellogenic Function in Brook Trout (Salvelinus fontinalis) by Exposure to Low pH

1987 ◽  
Vol 44 (3) ◽  
pp. 630-635 ◽  
Author(s):  
W. H. Tam ◽  
L. Birkett ◽  
R. Makaran ◽  
P. D. Payson ◽  
D. K. Whitney ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Acid Stress ◽  
Somatic Growth ◽  
Liver Weight ◽  
Liver Glycogen ◽  
Control Fish ◽  
Glucose Levels ◽  
Blood Glucose Levels

Brook trout (Salvelinus fontinalis), 1+ yr old, were exposed to pH 4.48 from February to December. Compared with control fish maintained at pH 7.34, acid-stressed fish generally had elevated blood glucose levels. Plasma cortisol concentration, measured only in males, was significantly increased in the acid-treated trout up to July. Although somatic growth decreased by about 30% by the end of the experiment, peritoneal fat was unchanged. During the reproductive season, female plasma levels of oestrogen and vitellogenin were the same at both pH levels. When immature fish were implanted with oestradiol-17β and then maintained for 21 d either in pH 7.34 (control) or 4.48, acid-treated fish again showed increased blood glucose levels. Liver weight increased at both pH levels, but liver glycogen was depleted and plasma vitellogenin was significantly increased by exogenous oesterogen only in control fish. It is postulated that before acclimation occurs, acid stress increases cortisol secretion, diverts nutrients normally used for growth to maintain a high blood sugar level, and affects the liver's ability to metabolize carbohydrates and synthesize vitellogenin.

Reduction in oocyte production and gonadotrope activity, and plasma levels of estrogens and vitellogenin, in brook trout exposed to low environmental pH

1990 ◽  
Vol 68 (12) ◽  
pp. 2468-2476 ◽  
Author(s):  
W. H. Tam ◽  
J. N. Fryer ◽  
B. Valentine ◽  
R. J. J. Roy
Keyword(s):  
Plasma Levels ◽  
Brook Trout ◽  
Acid Stress ◽  
Secretory Activity ◽  
Experimental Period ◽  
Acid Exposure ◽  
Control Fish ◽  
Cortisol Secretion ◽  
Control Value ◽  
The Mean

Maturing brook trout were exposed to pH 4.5 at the beginning of the rapid oocyte development phase in mid-June. The number of atretic follicles containing vitellogenic oocytes in acid-treated trout gradually increased with time, to exceed that of control fish on day 30, reaching a maximum (22–24% of all vitellogenic oocytes) between days 45 and 60 of acid exposure, before declining on day 73. Follicular atresia reduced the number of healthy vitellogenic oocytes in the acid-stressed fish to 59% of controls by day 60. Plasma vitellogenin and estrogen levels were not consistently affected by acid exposure. During the first 45 days of acid exposure, the mean weight of the healthy vitellogenic oocytes and the plasma levels of estrogen in the acid-exposed fish were at times significantly higher than those of control trout, but after day 45 these differences were no longer observed. Ultrastructural morphometry showed that secretory activity of the gonadotropes in the female acid-stressed brook trout was suppressed. Throughout the experimental period, the acid-exposed trout showed various symptoms characteristic of acid stress, such as elevated ACTH and cortisol secretion, hyperglycemia, acidosis, and hyponatremia. Food intake was reduced to 14% of the control value. These results suggest that the disruptive physiological changes and (or) reduced nutritional status associated with acid stress are responsible for the reduction in activity of the gonadotropes and oocyte atresia.

Arginine Vasotocin, an Osmoregulatory Hormone, as a Potential Indicator of Acid Stress in Fish

1991 ◽  
Vol 48 (2) ◽  
pp. 238-242 ◽  
Author(s):  
A. Hontela ◽  
J. B. Rasmussen ◽  
D. Ko ◽  
K. Lederis ◽  
G. Chevalier
Keyword(s):  
Early Warning ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Acid Stress ◽  
Arginine Vasotocin ◽  
Lower Plasma ◽  
Demineralized Water ◽  
Early Warning Indicators ◽  
Potential Indicator ◽  
Warning Indicators

Brook trout (Salvelinus fontinalis) exposed for 1 wk to pH 5.6 (sublethal acidity) exhibited higher forebrain and pituitary arginine vasotocin (AVT) levels and lower plasma Na+ levels than fish exposed to pH 6.7 (control). Addition of 300 μg total Al/L to water at pH 5.6 did not augment the effect on either the plasma Na+ or the AVT levels. Exposure to demineralized water for 1 wk lowered the plasma Na+ and increased AVT in the forebrain but had no effect on pituitary AVT. The increased AVT levels could be used as early warning indicators of sublethal acid stress in the brook trout. Such indicators, used in wild fish, might become important tools in management of trout lakes in areas threatened by acidification.

Iodide and thyroxine metabolism in the brook trout, Salvelinus fontinalis (Mitchill), during sustained exercise

1971 ◽  
Vol 49 (9) ◽  
pp. 1255-1269 ◽  
Author(s):  
D. A. Higgs ◽  
J. G. Eales
Keyword(s):  
Thyroid Hormone ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Specific Activity ◽  
Hormone Secretion ◽  
Conversion Ratio ◽  
Limited Extent ◽  
Thyroid Activity ◽  
Individual Variations ◽  
Serum Ratio

Iodide and thyroxine metabolism were followed in exercised and non-exercised starved trout.Radioiodide (125I) parameters suggested a slight increase in thyroid activity (% dose in thyroid, thyroid/serum ratio (T/S), and conversion ratio (CR)) and an increase in extrathyroidal 125I excretion resulting from exercise.The generally high and variable serum 127I levels increased up to 496 μg% during the experiments, being consistently higher in exercised fish. Individual variations in serum 127I were related in many instances to radioiodide parameters (I125I, T/S, CR) and to a limited extent to % thyroid. This demonstrates the uncertainty of radioiodide measurements when the specific activity of circulating 125I changes and the need for assessing 127I levels in radioiodide studies.Tissue uptake of radioactivity and serum loss of protein-bound radioactivity following radiothyroxine intraperitoneal injection, as well as serum stable thyronine levels, suggested both increased biliary loss of thyroid hormones and a higher thyroid hormone secretion rate as the result of exercise.

Elevated Levels of Arginine Vasotocin in the Brain of Brook Trout (Salvelinus fontinalis) from Acid Lakes: A Field Test of a Potential Biomarker for Acid Stress

1993 ◽  
Vol 50 (8) ◽  
pp. 1717-1727 ◽  
Author(s):  
A. Hontela ◽  
J. B. Rasmussen ◽  
K. Lederis ◽  
H. V. Tra ◽  
G. Chevalier
Keyword(s):  
Body Size ◽  
Field Test ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Acid Stress ◽  
Low Ph ◽  
Arginine Vasotocin ◽  
Potential Biomarker ◽  
Different Seasons ◽  
The Relationship

The levels of arginine vasotocin (AVT), an osmoregulatory peptide, were determined by radioimmunoassay in brain tissue of brook trout (Salvelinus fontinalis) of a wide size range (50–380 mm) from softwater Laurentian lakes ranging in pH from 5.0 to 6.9 at different seasons. Multivariate models (ANCOVA) were developed to quantify the relationship between AVT, pH, body size, and season. Brain AVT levels increased with body size, and the allometric slope was highest in the low-pH lakes (pH 5.0-5.5). Although brook trout > 150 mm had higher brain AVT levels at low pH, no significant differences were detected for brook trout < 150 mm. We hypothesize that the sensitivity of brook trout at the parr stage to acid stress may be linked to their inability to mobilize a hormonal response involving AVT. The seasonal variation in brain AVT levels was similar in all the lakes studied, summer levels being the highest. Although this field study revealed that AVT levels depend also on factors other than acid stress (body size and season), our ANCOVA models allow adjustment for the effects of these covariables. Analyses of this type can be used to field test and calibrate biomarkers for use in ecotoxicology.

scholarly journals The Effect of Non-Circadian Photoperiod on Growth and Puberty Onset of Brook Trout Salvelinus fontinalis Mitchill

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 692
Author(s):  
Katsiaryna Lundova ◽  
Jan Matousek ◽  
Vlastimil Stejskal
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Somatic Growth ◽  
Continuous Light ◽  
Control Group ◽  
Sexually Mature ◽  
Average Body ◽  
Average Body Weight

The aim of the present study was to assess the effects of a prolonged photoperiod on growth rate and sexual maturation in brook trout Salvelinus fontinalis. The task of the experiment was to determine the most effective light regimen capable to minimizing the effects of puberty, including impairment of somatic growth and further general characteristics. In this regard, the studied fish were reared under three photoperiod regimens in which fish were exposed to 24 h continuous light alternating with 24 or 48 h under the ambient photoperiod or 48 h continuous light alternating with a 24 h ambient photoperiod. A control group was reared under the natural ambient photoperiod. Four-hundred and fifty fish with an average initial body weight of 101.3 ± 1.2 g were used for each experimental group (three replicates of each treatment plus control). A statistically lower growth rate showed control groups in both sexes. At the end of the study, control males had an average body weight of 226.6 ± 39.8 g and control females a body weight of 199.8 ± 12.2 g. At the same period, a significantly higher average body weight was found in groups reared 24 h under ambient photoperiod alternating with a 48 h continuous light regime (2CP:1AP) in both sexes (296.56 ± 62.5 g—males, and 239.9 ± 19.2 g—females, respectively). A significantly higher percentage of sexually mature fish was observed in the control group (80% of males and 29% of females, respectively). We found significantly fewer sexually mature females compared to males. The lowest survival was observed in group 2CP:1AP at 92%. It was concluded that regimen under which fish was exposed to 48 h of natural ambient photoperiod alternating with 24 h of constant light (1CP:2AP) lead to the successful delay of gonad development and onset of puberty and increased somatic growth in both sexes.

Histopathological and electron microscopic studies of gills of brook trout, Salvelinus fontinalis, from acidified lakes

1985 ◽  
Vol 63 (9) ◽  
pp. 2062-2070 ◽  
Author(s):  
Gaston Chevalier ◽  
Laurent Gauthier ◽  
Guy Moreau
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Gill Tissue ◽  
Low Ph ◽  
Chloride Cells ◽  
Electron Microscopic ◽  
Secondary Lamellae ◽  
Microscopic Studies ◽  
Acidified Lakes ◽  
High Level

Histopathological and electron microscopic studies of gill tissue were carried out in brook trout, Salvelinus fontinalis, from wild populations inhabiting three acidified lakes and in others from three nonacidified lakes located in the Canadian Shield (Québec). The acidified lakes were characterized by low pH (5.5), poor buffering capacity, and low conductivity. By comparison with trout from nonacidified lakes, gills of trout from acidified lakes showed extensive epithelial damage, mainly separation of the epithelial layer from underlying tissue, deformation of secondary lamellae, and degeneration of chloride cells, which was accompanied by pronounced hyperplasia of undifferentiated epithelial cells in the primary lamellae. Histopathological changes were quantified by morphometry. Most damaged gills were also shown to contain a higher concentration of aluminum. The observed changes in gill cells and tissues are interpreted as reactions to sublethal environmental conditions adverse to the osmoregulatory balance of the fish, specifically chronic exposure to low pH and low calcium concentrations, possibly combined with a high level of aluminum.

Infectious Pancreatic Necrosis Virus and Bacterial Kidney Disease Appearing Concurrently in Populations of Salmo gairdneri and Salvelinus fontinalis

1975 ◽  
Vol 32 (1) ◽  
pp. 92-95 ◽  
Author(s):  
T. Yamamoto
Keyword(s):  
Kidney Disease ◽  
Brook Trout ◽  
Pancreatic Necrosis ◽  
Salvelinus Fontinalis ◽  
Electron Microscopic Examination ◽  
Infectious Pancreatic Necrosis Virus ◽  
Salmo Gairdneri ◽  
Electron Microscopic ◽  
Bacterial Kidney Disease ◽  
Infectious Pancreatic Necrosis

An investigation into disease problems at a hatchery revealed the coexistence of bacterial kidney disease and infectious pancreatic necrosis (IPN) virus in various lots of rainbow (Salmo gairdneri) and eastern brook (Salvelinus fontinalis) trout. During the study, increased mortality rates occurred in yearling brook trout with concurrent infections of bacterial kidney disease and IPN, but the mortality appeared to be primarily associated with the bacterial agent. Evidence is presented to indicate that infection with virus preceded the bacterial infection. Electron microscopic examination of kidney tissues showed that both agents could be found within the same cells.

Régulations aminergique et cholinergique du système caudal neurosécréteur de l'omble de fontaine, Salvelinus fontinalis, en relation avec l'osmo-iono-regulation

1983 ◽  
Vol 61 (12) ◽  
pp. 2856-2867 ◽  
Author(s):  
Laurent Gauthier ◽  
Céline Audet ◽  
Gaston Chevalier
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Light And Electron Microscopy ◽  
Neurosecretory Cells ◽  
Regulatory Function ◽  
Synthetic Activity ◽  
Neurosecretory System ◽  
Neurosecretory Material ◽  
Electron Microscopic ◽  
Caudal Neurosecretory System

The innervation of the caudal neurosecretory system of the brook trout, Salvelinus fontinalis, was studied under light and electron microscopy in order to characterize its nature, distribution, and regulatory function over the activity of the caudal neurosecretory cells. A dual innervation of the cell bodies and axons of neurosecretory cells was disclosed. One type of axosomatic connection exhibited small lucent vesicles and large dense-cored granules. These boutons were identified as monoaminergic since they appeared depleted after reserpine treatment and they were selectively labeled with 5-OH-dopamine. In fish exposed to demineralized water, reserpine induced a condition that stimulated the synthetic activity of caudal neurosecretory cells, a clear reduction of this activity, according to morphometric (cell and nucleus diameters) and ultrastructural criteria (dimensions of the Golgi complex). By comparison, no significant variation of the synthetic activity was noted in freshwater-adapted trout treated with reserpine. A second type of innervation was also identified as cholinergic by histochemical localization of acetylcholinesterase. Electron microscopic analysis also revealed axosomatic and axoaxonic cholinergic synaptic connections with characteristic small 500-Å diameter lucent vesicles. The injection of fenitrothion, an anticholinesterase agent, enhanced discharge of neurosecretory material from axonal endings of caudal cells while the synthetic activity did not appear to be modified. Our findings suggest an important role of aminergic and cholinergic controls over the response of the caudal neurosecretory system of Salvelinus fontinalis during hyperosmotic adaptation.

Blood Acid-Base Balance in Brook Trout (Salvelinus Fontinalis)

1979 ◽  
Vol 79 (1) ◽  
pp. 115-126
Author(s):  
RANDALL K. PACKER ◽  
ARTHUR L. SUNKIN
Keyword(s):  
Brook Trout ◽  
Base Excess ◽  
Salvelinus Fontinalis ◽  
Rapid Assessment ◽  
Respiratory Acidosis ◽  
Acid Base Balance ◽  
Acid Base ◽  
Plasma Protein Concentration ◽  
Base Balance ◽  
Aortic Cannula

A nomogram is presented which allows the rapid assessment of acid-base status in brook trout (Salvelinus fontinalis Mitchill) at 18 °C. Due to a PCO2 of 3.5-4.3 mmHg in the respirometer water, the fish from which data were obtained for determination of zero base excess values were suffering from slight respiratory acidosis. Trauma of surgery and anaesthetization as well as confinement in the respirometer might also have generated a slight metabolic acidosis. Base excess values for trout with a chronically implanted dorsal aortic cannula ranged from −3 to +3 m-equiv/l. Blood buffer values of d[HCO3−]/dpH = 7.50 ± 4.42 slykes and -d log10PCOCO2/d pH = 1.31 ± 0.14 were found. Mean plasma protein concentration was 3.6 ± 0.8 g/100 ml plasma and the buffering power of plasma was approximately 40% that of whole blood. Plasma proteins are more important blood buffers in fish than in humans.

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