Prolactin Cell Cytology, Plasma Electrolytes, and Whole-Body Sodium Efflux in Acid-Stressed Brook Trout (Salvelinus fontinalis)

1988 ◽  
Vol 45 (7) ◽  
pp. 1212-1221 ◽  
Author(s):  
J. N. Fryer ◽  
W. H. Tam ◽  
B. Valentine ◽  
R. E. Tikkala

Twelve-month-old brook trout (Salvelinus fontinalis) of both sexes were exposed to acidified water (pH 4 5) for a period of 52 d. Ultrastructural morphometric studies of the prolactin cells of the pituitaries of acid-stressed female trout revealed a reduction, after a latent period of about 1 wk, in prolactin cell area, cytoplasmic area and nuclear area which gradually recovered to control values by day 52 of acid exposure. In both male and female trout, acid exposure resulted in significant decreases in plasma osmolarity, and plasma sodium, which gradually returned to control values by day 52 of the study. Total plasma calcium was not altered by acid exposure in either male or female trout. For both male and female trout, acid exposure resulted in transient elevations in haematocrit and a prolonged suppression of blood pH. The whole-body sodium efflux for trout introduced into dechlorinated tap water or distilled water was significantly greater at pH 4.5 than at pH 7.35. Possible relationships between the acid-induced inhibition of the secretory activity of the prolactin cells and impairments in osmotic and ionic regulation observed in acid-stressed trout are discussed.


2004 ◽  
Vol 61 (4) ◽  
pp. 618-626 ◽  
Author(s):  
Katherine A Sloman ◽  
Graham R Scott ◽  
D Gordon McDonald ◽  
Chris M Wood

Competition for social status can result in physiological differences between individuals, including differences in ionoregulatory ability. Subordinate rainbow trout (Oncorhynchus mykiss) had two-fold higher uptake rates of sodium across the gill and two-fold higher whole-body sodium efflux rates than the dominant fish with which they were paired. Sodium efflux was then divided into branchial and renal components, both of which were higher in subordinates. Branchial sodium efflux accounted for 95%–98% of sodium loss. Plasma sodium concentrations were more variable, although not significantly different, in subordinate fish, suggesting that the increased loss of sodium in these trout is compensated for by an increase in uptake rates. Urine flow rates and plasma cortisol concentrations were higher in subordinate fish, but there was no difference in glomerular filtration rate between dominants and subordinates. Renal sodium reabsorption was significantly reduced in subordinates. In summary, the ionoregulation of subordinate individuals was altered, most likely occurring as a result of stress-induced changes in gill permeability, resulting in a higher throughput of water and increased branchial sodium efflux. These changes in ionoregulatory ability have many physiological implications, including the increased susceptibility of subordinates to ionoregulatory challenges and an increased metabolic cost of ionoregulation.



1990 ◽  
Vol 47 (8) ◽  
pp. 1593-1603 ◽  
Author(s):  
C. M. Wood ◽  
D. G. McDonald ◽  
C. G. Ingersoll ◽  
D. R. Mount ◽  
O. E. Johannsson ◽  
...  

Water Ca, rather than pH or Al, was the most important factor affecting whole body electrolyte levels in fry exposed from fertilization to swim-up (91 d) to 84 combinations of pH (6.5, 5.2, 4.8, 4.4, 4.0), Ca (0.5, 1, 2, 8 mg/L), and Al (0, 12, 37, 111, 333, 1000 μg/L) in flowing soft water. Aluminum accumulation occurred only at water Al levels > 111 μg/L; Al accumulation was inhibited both by increasing Ca and decreasing pH. Under control conditions (pH = 6.5, Ca = 2 mg/L, Al = 0 μg/L), whole body Na, Cl, K, and Ca levels all increased greatly during development, while Mg decreased. Body Ca levels were elevated up to 3-fold, and Na, Cl, and K up to 2-fold by increasing water Ca at the same pH and Al. Low pH had a small negative influence, intermediate levels of Al (37, 111) a slight positive influence, and higher levels of Al a negative influence on Na, Cl, K, and Ca levels. Whole body Mg showed opposite trends, reflecting delayed development under adverse conditions. At pH = 6.5, the positive influence of increasing water Ca on most whole body ions showed a clear threshold between 0.5 and 1 mg/L. At lower pH, this threshold was shifted to between 2 and 8 mg/L, indicating that Ca levels sufficient to support healthy development at circumneutral pH may prove inadequate under acidified conditions.



1978 ◽  
Vol 35 (8) ◽  
pp. 1084-1088 ◽  
Author(s):  
Wilbur L. Mauck ◽  
Paul M. Mehrle ◽  
Foster L. Mayer

Eyed eggs of brook trout (Salvelinus fontinalis) were exposed to Aroclor® 1254 (0.43–13 μg/L) for 10 d before hatching and the fry for 118 d after hatching. Median hatching time, egg hatchability, and sac fry survival were not affected by Aroclor 1254. At 48 d after hatching, growth was significantly (P < 0.05) decreased by Aroclor 1254 concentrations ≥ 1.5 μg/L, but no significant differences in growth of surviving fry were observed at the end of the 118-d exposure. Mortality occurred in fry exposed to 13 μg/L within 48 d of exposure, and after 118 d of exposure significant mortality occurred in the three highest concentrations. Biochemical constituents in brook trout fry related to growth and development were affected by Aroclor 1254. Hydroxyproline and vitamin C concentrations in sac fry (38 d old) were decreased by ≥ 3.1 μg/L. Backbone development in fry exposed for 118 d was significantly altered. Collagen was significantly decreased in the backbone as was the phosphorous concentration, while the calcium concentration increased. Hydroxyproline concentration in collagen isolated from the backbone was also decreased. The no-effect exposure concentration on backbone composition was < 0.43 μg/L. Whole body residues in fry exposed for 118 d were 40 000 to 47 000 times the concentration in water. Key words: brook trout, Salvelinus fontinalis, Aroclor® 1254, polychlorinated biphenyls, PCB, growth, bone development, vitamin C, collagen



1975 ◽  
Vol 32 (5) ◽  
pp. 609-613 ◽  
Author(s):  
Paul M. Mehrle ◽  
Foster L. Mayer Jr.

Twenty-two days before hatching, eyed eggs of brook trout (Salvelinus fontinalis) were placed in a flow-through system and continuously exposed to toxaphene (0, 39, 68, 139, 288, and 502 ng/liter) until they hatched and the resulting fry were exposed for a further 90 days. Hatchability was not affected by toxaphene, but all of the fry exposed to 502 and 288 ng/liter of toxaphene died by 30 and 60 days after hatch, respectively. Growth of fry was significantly depressed at the 139 and 288 ng/liter concentrations 30 days after hatch and at all concentrations after 60 and 90 days of toxaphene exposure.Whole body collagen of fry, as estimated by hydroxyproline, was significantly decreased in the four higher concentrations of toxaphene within 7–15 days after hatch. Backbone collagen was significantly decreased (P < 0.05) in 30-, 60-, and 90-day-old fry exposed to toxaphene, whereas calcium and phosphorus concentrations in the backbone were increased (P < 0.05). The mineral: collagen ratio was significantly increased by toxaphene. The whole body collagen of sac-fry was a good predictor of later growth and development of brook trout.



1988 ◽  
Vol 45 (9) ◽  
pp. 1587-1596 ◽  
Author(s):  
C. M. Wood ◽  
D. G. McDonald ◽  
C. E. Booth ◽  
B. P. Simons ◽  
C. G. Ingersoll ◽  
...  

Brook trout (Salvelinus fontinalis) adapt to chronic sublethal acid/Al stress. The accompanying acclimation confers greater resistance to short-term increases in Al and acidity. Adult trout were exposed in flowing soft water to eight combinations of pH (6.5, 5.2) × Ca2+ (25, 400 μequiv/L) × Al (0, 75, 150 μg/L = 0, 2.8, 5.6 μmol/L). After 10 wk, blood sampling by caudal puncture revealed no significant variations in osmolality, plasma protein, or hemoglobin and only minor differences [Formula: see text] in plasma Na+ and Cl−. Overall, most electrolytes were higher in fish exposed to higher water Al and/or Ca2+; only plasma Ca2+ was directly depressed by low pH. Hematocrit was raised by both low pH and elevated Al. When trout naive to both acid and Al were challenged with pH = 4.8, Al = 333 μg/L under flow-through conditions, there were large negative whole-body Na+ fluxes and marked depressions of plasma Na+ and Cl−, hemoconcentration, and substantial mortality over 48 h. Prior exposure for 10 wk to pH = 5.2 plus either 75 or 150 μg Al/L prevented mortality and ameliorated or abolished these effects through a more rapid recovery of net Na+ balance. Prior exposure to pH = 5.2 alone ameliorated these effects only slightly.



1974 ◽  
Vol 60 (2) ◽  
pp. 267-273
Author(s):  
WARREN R. FLEMING ◽  
JAMES NICHOLS ◽  
W. T. W. POTTS

1. Transfer of Fundulus kansae from 80 % sea water to a low-calcium water containing 0.4 mm/1 Ca2+ caused a sharp rise in sodium efflux and a change in the kinetic pattern of efflux. 2. A transient drop in whole-body sodium levels occurred within 1-2 days after transfer. Both sodium and potassium levels were normal after 9 days exposure to low-calcium saline. 3. Transfer into low-calcium sea water increased the rate of incorporation of radio-phosphorus into gill RNA. 4. Actinomycin-D blocked the stimulation of sodium turnover after transfer into low-calcium sea water. It did not affect the whole-body sodium or potassium levels of long-term sea-water adapted animals. 5. Actinomycin-D reduced the sodium efflux of short-term sea-water adapted animals regardless of the environmental calcium concentration. The antibiotic also upset the balance of sodium fluxes in those animals held in low-calcium sea water. 6. It is suggested that in addition to the generalized effect of calcium on permeability to monovalent ions and water, calcium serves to inhibit some of the synthetic processes involved in regulating sodium metabolism, and also serves to stabilize the metabolic machinery already present.



1963 ◽  
Vol 20 (4) ◽  
pp. 859-897 ◽  
Author(s):  
Nancy E. Henderson

Brook trout were exposed to photoperiods ranging from 4 to 20 hours per day and were held either at 8.5 °C or at 16°. The average diameter of the ova was used as an index of ovarian development while testicular maturation was determined from histological preparations.The gonadal cycles of both male and female trout were markedly affected by different photoperiodic regimes. The influence of long or short photoperiods depends upon the phase of gametogenesis in progress at the time and on the photoperiod in effect during earlier stages of the gonadal cycle. Evidence is presented which suggests that the maturation cycle of the gonads may be regulated by the normal seasonal changes of day length.An accelerated light regime can hasten the time of functional maturity in adult trout, but is without effect when applied to maturing fish in which gametogenesis is taking place for the first time. It is suggested that a stimulative effect of environmental factors is dependent upon maturation of the hypothalamic-hypophyseal mechanism.The rate of gonadal development is the same at 16° as it is at 8.5° provided the fish are exposed to natural day lengths. If fish are subjected to long or to short photoperiods, the gonadal response at 16° is quite different from that at 8.5°.



1989 ◽  
Vol 46 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Lawrence R. Curtis ◽  
Wayne K. Seim ◽  
Lisbeth K. Siddens ◽  
Debra A. Meager ◽  
Richard A. Carchman ◽  
...  

Acidification of streams and rivers associated with rainstorm or snowmelt events is often episodic as are many environmental introductions of toxic substances. We examined the toxicity of continuous or intermittent exposures to sulfuric acid (H+) to brook trout (Salvelinus fontinalis) embryos, alevins, and fry. Acute toxicity tests were conducted with juvenile rainbow trout (Salmo gairdneri). These studies permitted evaluation of key components of intermittent exposures (toxicant concentration, exposure duration, and recovery period) on mortality, reduced growth, and perturbed electrolyte balance. Lethality of H+ markedly changed with developmental stage of brook trout. Resistance of the chorion to H+ penetration probably protected embryonic fish, while hatching and onset of active swimming exacerbated H+ toxicity. Response surface methods demonstrated that between pH 4 and 7, time–concentration relationships for H+ toxicity were greatly influenced by exposure duration and peak concentration but little by length of recovery period. Daily pulses at pH 4 with duration as short 4.5 h produced marked mortality after 90 d. This did not occur after 4–60 d of testing. Whole-body Na+, K+, and Ca2+ concentrations of brook trout were negatively correlated with mean H+ concentrations after 90 d of exposure. Cation depletion appeared to be a more sensitive index of chronic, sublethal H+ toxicity than reduced growth.



1987 ◽  
Vol 44 (1) ◽  
pp. 99-104 ◽  
Author(s):  
Darrel Jon Laurén ◽  
D. G. McDonald

Juvenile rainbow trout (Salmo gairdneri) were exposed to 55 μg copper∙L−1 for 28 d and then transferred to uncontaminated water for 7 d. Whole body sodium concentration and sodium uptake (Jin) were measured at weekly intervals; Jin was measured at various Na+ concentrations and kinetic parameters estimated. After 24 h of copper exposure, the maximum rate of sodium uptake (Jmax) was inhibited by 55%, the affinity for sodium (Km) reduced by 49%, and whole body Na+ decreased by about 12.5%. After 7 d of exposure, whole body Na+ had returned to control values, but Jmax was still inhibited by 41%. Recovery of whole body Na+ occurred largely by a reduction of sodium efflux (Jout). Both Jmax and Km continued to recover until day 28, at which time Jin had returned to control values. We conclude that acclimation to sublethal copper depends on changes in both Na+ transport and permeability.



Sign in / Sign up

Export Citation Format

Share Document