Growth hormone transgenesis and polyploidy increase metabolic rate, alter the cardiorespiratory response and influence HSP expression in response to acute hypoxia in Atlantic salmon ( Salmo salar ) yolk-sac alevins
Growth hormone (GH)-transgenic Atlantic salmon display acceleratedgrowth rates compared with non-transgenics. GH-transgenic fish alsodisplay cardiorespiratory and metabolic modifications that accompanythe increased growth rate. An elevated routine metabolic rate hasbeen described for pre- and post-s...
| Published in: | Journal of Experimental Biology |
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| Main Authors: | , , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Company Of Biologists Ltd
2014
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| Subjects: | |
| Online Access: | https://doi.org/10.1242/jeb.098913 http://www.ncbi.nlm.nih.gov/pubmed/24675560 http://ecite.utas.edu.au/98698 |
| Summary: | Growth hormone (GH)-transgenic Atlantic salmon display acceleratedgrowth rates compared with non-transgenics. GH-transgenic fish alsodisplay cardiorespiratory and metabolic modifications that accompanythe increased growth rate. An elevated routine metabolic rate hasbeen described for pre- and post-smolt GH-transgenic salmon thatalso display improvements in oxygen delivery to support theincreased aerobic demand. The early ontogenic effects of GHtransgenesis on the respiratory and cellular physiology of fish,especially during adverse environmental conditions, and the effect ofpolyploidy are unclear. Here, we investigated the effects of GHtransgenesis and polyploidy on metabolic, heart and ventilation ratesand heat shock protein (HSP) levels after exposure to acute hypoxiain post-hatch Atlantic salmon yolk-sac alevins. Metabolic ratedecreased with decreasing partial pressures of oxygen in allgenotypes. In normoxia, triploid transgenics displayed the highestmass-specific metabolic rates in comparison to diploid transgenicsand non-transgenic triploids, which, in contrast, had higher rates thandiploid non-transgenics. In hypoxia, we observed a lower massspecificmetabolic rate in diploid non-transgenics compared with allother genotypes. However, no evidence for improved O 2 uptakethrough heart or ventilation rate was found. Heart rate decreased indiploid non-transgenics while ventilation rate decreased in bothdiploid non-transgenics and triploid transgenics in severe hypoxia.Regardless of genotype or treatment, inducible HSP70 was notexpressed in alevins. Following hypoxia, the constitutive isoform ofHSP70, HSC70, decreased in transgenics and HSP90 expressiondecreased in all genotypes. These data suggest that physiologicalchanges through GH transgenesis and polyploidy are manifestedduring early ontogeny in Atlantic salmon. |
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