Browsing Department of Biological Sciences by Author "Hansen, Tom Johnny"
Now showing items 1-18 of 18
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Atlantic salmon male post-smolt maturation can be reduced by using a 3-hour scotophase when inducing smoltification
Fraser, Thomas; Hansen, Tom Johnny; Norberg, Birgitta; Nilsen, Tom Ole; Schulz, Rüdiger W.; Fjelldal, Per Gunnar (Journal article; Peer reviewed, 2023)Photoperiod regulates the occurrence of unwanted male post-smolt maturation during the production of large (>100 g) Atlantic salmon (Salmo salar) smolts. However, the optimal daylength for triggering smoltification, but ... -
Autosomal sdY pseudogenes explain discordances between phenotypic sex and DNA marker for sex identification in Atlantic salmon
Ayllon, Fernando; Solberg, Monica Favnebøe; Besnier, Francois; Fjelldal, Per Gunnar; Hansen, Tom Johnny; Wargelius, Anna; Edvardsen, Rolf Brudvik; Glover, Kevin (Journal article; Peer reviewed, 2020)Despite the key role that sex-determination plays in evolutionary processes, it is still poorly understood in many species. In salmonids, which are among the best studied fishes, the master sex-determining gene sexually ... -
Changes in water temperature and oxygen: the effect of triploidy on performance and metabolism in large farmed Atlantic salmon
Sambraus, Florian; Remen, Mette; Olsen, Rolf Erik; Hansen, Tom Johnny; Waagbø, Rune; Torgersen, Thomas; Lock, Erik-Jan; Imsland, Albert; Fraser, Thomas W.K.; Fjelldal, Per Gunnar (Peer reviewed; Journal article, 2018)In salmon farming, the use of sterile triploids (3N) can mitigate the problem of escapees interbreeding with wild salmon. However, triploid salmon appear less tolerant to high water temperatures and low oxygen levels ... -
Chromosome aberrations in pressureinduced triploid Atlantic salmon
Glover, Kevin; Harvey, Alison C.; Hansen, Tom Johnny; Fjelldal, Per Gunnar; Besnier, Francois; Bos, J.B.; Ayllon, Fernando; Taggart, John B.; Solberg, Monica Favnebøe (Journal article; Peer reviewed, 2020)Background Triploid organisms have three sets of chromosomes. In Atlantic salmon, hydrostatic pressure treatment of newly fertilized eggs has been extensively used to produce triploids which are functionally sterile due ... -
Cloned and outbred Atlantic salmon display equal parasite dispersion when infected with the salmon louse
Glover, Kevin; Hansen, Tom Johnny; Besnier, Francois; Solberg, Monica Favnebøe; Fjelldal, Per Gunnar; Sørvik, Anne Grete Eide; Dalvin, Sussie; Nilsen, Frank (Peer reviewed; Journal article, 2017-11)The salmon louse is an ectoparasitic copepod that infects salmonids in the marine environment. This parasite causes a major economic and biological challenge to the Atlantic salmon farming industry, and efforts to increase ... -
The Distribution of IgT mRNA+ Cells in the Gut of the Atlantic Salmon (Salmo salar L.)
Castro, Pedro Luis; Barac, Fran; Hansen, Tom Johnny; Fjelldal, Per Gunnar; Hordvik, Ivar; Bjørgen, Håvard; Koppang, Erling Olaf (Journal article; Peer reviewed, 2023)The newly discovered IgT+ B cell is thought to play a dominant role in mucosal immunity, but limited studies have examined its distribution in fish species, hindering our understanding of its function. This study investigated ... -
Growth Performance, Nutrient Digestibility, and Retention in Atlantic Salmon, Salmo salar L., Fed Diets with Fermented Sugar Kelp, Saccharina latissima
Sartipiyarahmadi, Sahar; Philip, Antony Jesu Prabhu; Sveier, Harald; Steinsund, Silje; Lock, Erik Jan Robert; Madaro, Angelico; Hansen, Tom Johnny; Wiech, Martin; Strand, Øivind; Jakobsen, Jan Vidar; Van Der Heide, Marleen E.; Nørgaard, Jan Værum; Remø, Sofie C. (Journal article; Peer reviewed, 2023)Using low trophic marine resources such as sugar kelp (Saccharina latissimi) is of great interest to increase the circular food production in the ocean. Sugar kelp does, however, contain high levels of carbohydrates and ... -
Impact of Antioxidant Feed and Growth Manipulation on the Redox Regulation of Atlantic Salmon Smolts
Yin, Peng; Bjørnsson, Bjørn Thrandur; Fjelldal, Per Gunnar; Saito, Takaya; Remø, Sofie C.; Edvardsen, Rolf Brudvik; Hansen, Tom Johnny; Sharma, Sandeep; Olsen, Rolf Erik; Hamre, Kristin (Journal article; Peer reviewed, 2022-08-30)Accumulating evidence indicates a close relationship between oxidative stress and growth rate in fish. However, the underlying mechanisms of this relationship remain unclear. This study evaluated the combined effect of ... -
The influence of vgll3 genotypes on sea age at maturity is altered in farmed mowi strain Atlantic salmon
Ayllon, Fernando; Solberg, Monica Favnebøe; Glover, Kevin; Mohammadi, Faezeh; Kjærner-Semb, Erik Nordtorp; Fjelldal, Per Gunnar; Andersson, Eva; Hansen, Tom Johnny; Edvardsen, Rolf; Wargelius, Anna (Peer reviewed; Journal article, 2019-05-06)Background: In Atlantic salmon in the wild, age at maturity is strongly influenced by the vgll3 locus. Under farming conditions, light, temperature and feeding regimes are known significantly advance or delay age at maturity. ... -
No environmental effect on vaccine-induced reduced growth in Atlantic salmon Salmo salar smolts
Fraser, Thomas; Fjelldal, Per Gunnar; Sommerset, Ingunn; Søfteland, Tina; Høstmark, Ole; Powell, Mark; Heen, Vegar; Hansen, Tom Johnny (Journal article; Peer reviewed, 2020)Oil-adjuvanted vaccines reduce long-term growth in farmed Atlantic salmon Salmo salar, possibly via an increase in metabolic rate due to the energetic demands of the immune system. We tested this hypothesis by comparing ... -
Ploidy elicits a whole-genome dosage effect: growth of triploid Atlantic salmon is linked to the genetic origin of the second maternal chromosome set
Harvey, Alison C.; Fjelldal, Per Gunnar; Solberg, Monica Favnebøe; Hansen, Tom Johnny; Glover, Kevin (Peer reviewed; Journal article, 2017-04-11)Background: The Atlantic salmon aquaculture industry is investigating the feasibility of using sterile triploids to mitigate genetic interactions with wild conspecifics, however, studies investigating diploid and triploid ... -
Production and verification of the first Atlantic salmon (Salmo salar L.) clonal lines
Hansen, Tom Johnny; Penman, David J.; Glover, Kevin; Fraser, Thomas; Vågseth, Tone; Thorsen, Anders; Sørvik, Anne Grete Eide; Fjelldal, Per Gunnar (Journal article; Peer reviewed, 2020)Background In several fish species homozygous and heterozygous clonal lines have been produced using gynogenetic and androgenetic techniques. These lines are standardized and can be reproduced over generations. In rainbow ... -
Seasonal Changes in Photoperiod: Effects on Growth and Redox Signaling Patterns in Atlantic Salmon Postsmolts
Yin, Peng; Saito, Takaya; Fjelldal, Per Gunnar; Björnsson, Björn Thrandur; Remø, Sofie C.; Hansen, Tom Johnny; Sharma, Sandeep; Olsen, Rolf-Erik; Hamre, Kristin (Journal article; Peer reviewed, 2023)Farmed Atlantic salmon reared under natural seasonal changes in sea-cages had an elevated consumption of antioxidants during spring. It is, however, unclear if this response was caused by the increase in day length, ... -
A transcriptomic analysis of diploid and triploid Atlantic salmon lenses with and without cataracts
Olsvik, Pål Asgeir; Finn, Roderick Nigel; Remø, Sofie C.; Fjelldal, Per Gunnar; Chauvigné, Francois; Glover, Kevin; Hansen, Tom Johnny; Waagbø, Rune (Journal article; Peer reviewed, 2020)To avoid negative environmental impacts of escapees and potential inter-breeding with wild populations, the Atlantic salmon farming industry has and continues to extensively test triploid fish that are sterile. However, ... -
Triploid Atlantic salmon and triploid Atlantic salmon × brown trout hybrids have better freshwater and early seawater growth than diploid counterparts
Fraser, Thomas; Lerøy, Hilde; Hansen, Tom Johnny; Skjæraasen, Jon Egil; Tronci, Valentina; Pinto Pedrosa, Cindy; Fjelldal, Per Gunnar; Nilsen, Tom Ole (Journal article; Peer reviewed, 2021)The use of reproductively sterile triploid salmonids would enhance the environmental sustainability of the aquaculture industry by preventing genetic exchange between escapees and wild conspecifics. To this end, we assessed ... -
Triploidy leads to a mismatch of smoltification biomarkers in the gill and differences in the optimal salinity for post-smolt growth in Atlantic salmon
de Fonseka, Raneesha; Fjelldal, Per Gunnar; Sambraus, Florian; Nilsen, Tom Ole; Remø, Sofie C.; Stien, Lars Helge; Reinardy, Helena; Madaro, Angelico; Hansen, Tom Johnny; Fraser, Thomas (Journal article; Peer reviewed, 2022)Sterile triploid Atlantic salmon (Salmo salar) show inconsistent seawater grow-out, but the reason why remains unclear. The purpose of this study was to determine the salinity optima of triploid post-smolts. Diploids and ... -
Vgll3 and the Hippo pathway are regulated in Sertoli cells upon entry and during puberty in Atlantic salmon testis
Kjærner-Semb, Erik Nordtorp; Ayllon, Fernando; Kleppe, Lene; Sørhus, Elin; Skaftnesmo, Kai Ove; Furmanek, Tomasz; Segafredo, Frida Thyri; Thorsen, Anders; Fjelldal, Per Gunnar; Hansen, Tom Johnny; Taranger, Geir Lasse; Andersson, Eva; Schulz, Rüdiger W.; Wargelius, Anna; Edvardsen, Rolf (Peer reviewed; Journal article, 2018-01-30)Vgll3 is linked to age at maturity in Atlantic salmon (Salmo salar). However, the molecular mechanisms involving Vgll3 in controlling timing of puberty as well as relevant tissue and cell types are currently unknown. Vgll3 ... -
Water temperature and dietary histidine affect cataract formation in Atlantic salmon (Salmo salar L.) diploid and triploid yearling smolt
Sambraus, Florian; Fjelldal, Per Gunnar; Remø, Sofie C.; Hevrøy, Ernst Morten; Nilsen, Tom Ole; Thorsen, Anders; Hansen, Tom Johnny; Waagbø, Rune (Peer reviewed; Journal article, 2017-09)The aim of the present study was to investigate cataract development in diploid (2N) and triploid (3N) Atlantic salmon smolts and post-smolts at two water temperatures (10 and 16 °C) given diets with different histidine ...