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- Ellis, T, et al.
(author)
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Non-invasive measurement of cortisol and melatonin in tanks stocked with seawater Atlantic salmon
- 2007
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In: Aquaculture. - : Elsevier BV. - 0044-8486. ; 272:1-4, s. 698-706
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Journal article (peer-reviewed)abstract
- This study examined the potential for non-invasive assessment of cortisol and melatonin status of seawater Atlantic salmon, by measurement of hormone release into the water using methodology developed recently for freshwater rainbow trout. Validation experiments demonstrated good recoveries of spiked cortisol (ca. 95%) and melatonin (ca. 85%) from seawater, that oxygenation of seawater did not affect recovery, and that only small losses occurred during freeze storage of samples. When groups of seawater Atlantic salmon were transferred to experimental tanks, water cortisol concentrations reduced over the first few days — indicating an acclimation response. Subsequent exposure to a handling stress caused a rapid 50-fold increase in water cortisol concentration, followed by a decrease. In a separate experiment, water cortisol levels were elevated in tanks of fish previously exposed to infectious pancreatic necrosis virus, and cortisol release rate was correlated to plasma cortisol level. Water sampling from tanks holding seawater salmon showed that water melatonin concentrations were elevated at night, conforming to expectation. These experiments demonstrate that the cortisol and melatonin status of seawater Atlantic salmon in tanks can be monitored non-invasively by water sampling, with the particular advantage that hormonal status can be tracked over time as the fish are not disturbed by sampling.
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| 3. |
- Sundh, Henrik, 1976, et al.
(author)
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Environmental salinity regulates production rates of the antagonizing calciumreguatory hormones 1,25-dihydroxyvitamin D3 and 24,25- dihydroxyvitamin D3 in rainbow trout, Oncorhynchus mykiss
- 2007
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In: General and Comparative Endocrinology. - : Elsevier BV. - 0016-6480. ; 152:2-3, s. 252-258
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Journal article (peer-reviewed)abstract
- Previous studies have shown that specific binding of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) to enterocyte basolateral membranes (BLM), as well as circulating concentrations, is affected in response to changes in environmental salinity. It is not known if the production of 1,25(OH)2D3 and 24,25(OH)2D3 is affected by environmental salinity. The aim of the present study was to measure the in vitro production of [3H]-1,25(OH)2D3 and [3H]-24,25(OH)2D3 in fresh water (FW) and after 1, 2, 3, and 7 days after transfer to seawater (SW). Pooled sub-cellular fractions (mitochondria and microsomes) from liver or kidney was incubated with [3H]-25(OH)D3 and the produced metabolites were separated using HPLC. Hepatic production of [3H]-1,25(OH)2D3 was decreased after 24 h in SW. This was followed by an up-regulation after 48 h and a second, slower decrease in production rate which leveled out after 7 days in SW. The production rate in SW was lower than the original rate in FW-adapted fish. For hepatic [3H]-24,25(OH)2D3 production the pattern was reversed. Renal production of [3H]-24,25(OH)2D3 increased significantly during the period of SW acclimation. These results suggest that environmental salinity regulates the production rate of the two antagonizing calcium regulatory hormones; 1,25(OH)2D3 and 24,25(OH)2D3. This gives further evidence to the hypothesis that there is a physiological regulation and a differentiated importance of 1,25(OH)2D3 and 24,25(OH)2D3 in relation to environmental calcium concentrations.
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