Influence of Salinity, Temperature, and Exercise on Plasma Osmolality and Ionic Concentration in Atlantic Salmon (Salmo salar)

1972 ◽  
Vol 29 (8) ◽  
pp. 1217-1220 ◽  
Author(s):  
J. M. Byrne ◽  
F. W. H. Beamish ◽  
R. L. Saunders

In unexercised Atlantic salmon (Salmo salar), plasma osmolality and Na+ and Ca++ concentrations varied little at temperature-salinity combinations of 3, 5, 10, and 14 C and 0, 15, and 30‰. Plasma K+ tended to increase with increase in temperature. Cl− values were similar at 5 and 14 C. At 1 C and 0‰, lower plasma osmolalities indicated reduced ability to osmoregulate. At 1 C and 30‰, elevated osmolalities and ionic values and mortalities indicated severe osmotic stress.After exercise for 2 hr at 3–4 body lengths/sec at 5 and 14 C, salmon in salinities of 0 and 15‰ had osmolalities and ionic values the same as or little changed from unexercised values. There were marked increases in the values following exercise in 30‰.


1999 ◽  
Vol 56 (11) ◽  
pp. 2078-2086 ◽  
Author(s):  
Frode Kroglund ◽  
Magne Staurnes

Groups of Atlantic salmon (Salmo salar) smolts were held 1-13 days in soft water with a pH range of 5.0-6.6, concentrations of labile inorganic monomeric Al (Ali) of 10-90 µg·L-1, and 0.7-2.3 mg Ca·L-1. Fish were exposed to either naturally acidic water from a river in southwestern Norway, limed water from the same river, mixtures of acidic and limed river water, acidic river water with sulfuric acid and Al added, or limed river water with additional lime. Mortality was observed in all groups exposed to water with pH < 5.8 and containing 30-90 µg Ali·L-1. No fish died in water with pH > 5.8 and 15-20 µg Ali·L-1, but fish in water with pH 5.8-6.2 had lower plasma Cl- concentration and gill Na+,K+-ATPase activity than fish in water with pH > 6.5. Smolts exposed to pH < 5.8 were unable to survive in seawater, and smolts exposed to water with pH 5.8-6.2 had lower hypoosmoregulatory capacity than smolts exposed to water with pH > 6.5. These results show that even moderately acidified water with low Al concentrations impairs smoltification and reduces the seawater tolerance of Atlantic salmon smolts.



1990 ◽  
Vol 47 (12) ◽  
pp. 2431-2440 ◽  
Author(s):  
S. B. Brown ◽  
R. E. Evans ◽  
H. S. Majewski ◽  
G. B. Sangalang ◽  
J. F. Klaverkamp

Sexually maturing Atlantic salmon, Salmo salar, were held, in the acidic (pH range 4.7–5.2) Westfield River, Nova Scotia and in the nearby, less acidic (pH range 5.2–5.6) Medway River. Exposure to Westfield River water in 1985 (149 d) and 1986 (126 d) reduced plasma osmolality, Na+, Cl−, and Ca++ (in females only) concentrations of post-spawning fish compared to those in fish held in the Medway River. There were coincidental increases in plasma K+, glucose, and unidentified osmotic fraction (UOF). Gill tissue showed hyperplasia of primary lamellae epithelium. Together, these findings indicate compromised ionoregulatory ability. Decreased plasma T3 (3,5,3′-triiodo-L-thyronine) suggests altered thyroid function. Westfield River water did not affect plasma T4(L-thyroxine) or protein concentrations. An unintentional handling stress caused even more severely depressed plasma ions and more elevated plasma glucose in Westfield fish in 1985 relative to 1986; Medway fish largely recovered from this stress. These observations indicate that acid-exposed fish may be more sensitive to additional stressors. Limestone treatment of Westfield River water (elevating its pH to Medway values) ameliorated ionoregulatory ability but did not affect plasma T3 and Ca++ (female). A high salt diet (3% NaCl) failed to protect salmon from the effects of acidic water.



1991 ◽  
Vol 48 (2) ◽  
pp. 164-169 ◽  
Author(s):  
J. Duston ◽  
R. L. Saunders ◽  
D. E. Knox

Two-year-old (2+) Atlantic salmon (Salmo salar) raised under ambient temperature and simulated natural photoperiod (45°N) completed smolting between February and May, exhibiting significant increases in gill Na+, K+-ATPase activity and salinity tolerance (96 h, 37.5 ppt) but no significant changes in plasma osmolality. On May 2 the smolts were divided into four groups (each n = 80) and subjected to a rapid (2–3 h) increase in temperature from ambient (5 °C) to 10, 13, or 16 °C or remained ambient (control) which rose to 12 °C by the end of the experiment on June 5. In the 10, 13, and 16 °C groups, mean gill Na+, K+-ATPase activity (micromoles inorganic phosphorus per milligram protein per hour) declined significantly from 6.6 units on May 2 to 4.3, 3.6, and 2.3 units, respectively, on May 23. In the control group, Na+, K+-ATPase activity showed no significant changes during the study. Plasma osmolality was maintained in all groups between 290 and 304 mosmol∙kg−1. Salinity tolerance tests revealed a significant decline in survival in the 16 °C group from May 2 and in the 10 °C, 13 °C, and control groups from May 13, but no significant differences were observed among the three groups. The results support the hypothesis that increases in freshwater temperature accelerate the loss of hypoosmoregulatory capacity.



2005 ◽  
Vol 62 (11) ◽  
pp. 2661-2672 ◽  
Author(s):  
P Mackie ◽  
P A Wright ◽  
B D Glebe ◽  
J S Ballantyne

This study reports that families of Atlantic salmon (Salmo salar) smolts vary in their ability to osmo- and iono-regulate following abrupt transfer to cold seawater. Eleven families of Atlantic salmon 0+ smolts were held in fresh water (2.4–4 °C) or transferred to seawater (1.9–4 °C) and sampled 0 h, 24 h, 96 h, and 30 days post-transfer. Plasma osmolality was significantly different among the families after 24 h of seawater exposure. The family with the lowest osmolality at 24 h also displayed the lowest plasma Cl– concentrations as well as the highest gill Na+/K+ ATPase activity. Gill mRNA expression of the Na+/K+ ATPase α1b isoform increased following seawater exposure, whereas the α1a isoform decreased, but there was no significant difference among families. Taken together, the interfamily differences in osmoregulatory ability are correlated with gill Na+/K+ ATPase activity but not the expression of two salinity-sensitive Na+/K+ ATPase isoforms. Furthermore, the data indicate that family differences in gill Na+/K+ ATPase activity were only apparent when assayed at the sampling temperature (4 °C) and not at a higher assay temperature (10 °C).



1997 ◽  
Vol 54 (3) ◽  
pp. 503-511 ◽  
Author(s):  
M P Wilkie ◽  
M A Brobbel ◽  
K G Davidson ◽  
L Forsyth ◽  
B L Tufts

Atlantic salmon (Salmo salar) were acclimated and exhaustively exercised at 12, 18, or 23°C to determine how temperature influences the magnitude of postexercise physiological disturbances. At each temperature, exercise led to decreased white muscle ATP and phosphocreatine concentrations. Phosphocreatine was rapidly restored within 1 h at each temperature whereas ATP restoration took 1-4 h at 18 and 23°C, but considerably longer at 12°C. Exercise-induced depletions of white muscle glycogen were accompanied by elevations in muscle lactate, which contributed to 0.6 unit decreases in white muscle intracellular pH (pHi) at each temperature. Compared with rates of recovery in warmer water, glycogen resynthesis, lactate catabolism, and pHicorrection were slower at 12°C. White muscle REDOX state estimates suggested that slower postexercise recovery at 12°C was not due to oxygen delivery limitations. Marked postexercise elevations in plasma osmolality and lactate concentration were also observed and in each case correction of the disturbance took longer at 12°C. Paradoxically, significant mortality (30%) was observed only at 23°C. We conclude that while warmer water facilitates postexercise recovery of white muscle metabolic and acid-base status in Atlantic salmon, extremely high temperatures may make them more vulnerable to delayed postexercise mortality.



2001 ◽  
Vol 32 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Sjofn Sigurgisladottir ◽  
Margret S. Sigurdardottir ◽  
Helga Ingvarsdottir ◽  
Ole J. Torrissen ◽  
Hannes Hafsteinsson


2005 ◽  
Vol 68 (7) ◽  
pp. 1336-1339 ◽  
Author(s):  
L. L. NESSE ◽  
T. LØVOLD ◽  
B. BERGSJØ ◽  
K. NORDBY ◽  
C. WALLACE ◽  
...  

The objective of our experiments was to study the persistence and dissemination of orally administered Salmonella in smoltified Atlantic salmon. In experiment 1, salmon kept at 15°C were fed for 1 week with feed contaminated with 96 most-probable-number units of Salmonella Agona per 100 g of feed and then starved for 2 weeks. Samples were taken from the gastrointestinal tract and examined for Salmonella 1, 2, 8, 9, 15, and 16 days after the feeding ended. In experiment 2, Salmonella Agona and Montevideo were separately mixed with feed and administered by gastric intubation. Each fish received 1.0 × 108, 1.0 × 106, or 1.0 × 104 CFU. The different groups were kept in parallel at 5 and 15°C and observed for 4 weeks. Every week, three fish in each group were sacrificed, and samples were taken from the skin, the pooled internal organs, the muscle, and the gastrointestinal tract and examined for the presence of Salmonella. The results from the two experiments showed that the persistence of Salmonella in the fish was highly dependent on the dose administered. Salmonella was not recovered from any of the fish that were fed for 1 week with the lowest concentration of Salmonella. In the fish given the highest dose of Salmonella, bacteria persisted for at least 4 weeks in the gastrointestinal tract as well as, to some extent, the internal organs. The present study shows that under practical conditions in Norway, the risk of Salmonella in fish feed being passed on to the consumer of the fish is negligible.



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