English
norskBlar i forfatter "Tveiten, Helge"
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Cold seawater induces early sexual developmental stages in the BPG axis of European eel males
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-22)<i>Background</i>: The impossibility of closing the life cycle of the European eel (<i>Anguilla anguilla</i>) in captivity troubles the future of this critically endangered species. In addition, the European eel is a highly valued and demanded resource, thus the successful closing of its life cycle would have a substantial economic and ecological impact. With the aim of obtaining the highest ... -
Development of Atlantic Salmon (Salmo salar L.) Under Hypoxic Conditions Induced Sustained Changes in Expression of Immune Genes and Reduced Resistance to Moritella viscosa
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-02)Atlantic salmon is characterized with high sensitivity to low dissolved oxygen (DO) levels. Hypoxia can affect diverse biological processes with consequences that can be manifested immediately or with delay. Effects of hypoxia on the immune system and the resistance to a bacterial pathogen were investigated. Two groups were reared at, respectively, normal (NO, 80–100%) and low (LO, 60%) levels of ... -
Effects of weathered polyethylene microplastic ingestion on sexual maturation, fecundity and egg quality in maturing broodstock Atlantic cod Gadus morhua
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-01-09)Microplastics (MPs) have become a global issue as they are omnipresent in the ocean. Fish ingesting MPs through feed could be affected in their physiological function, e.g., disrupted enzyme production and function, reduction of feeding and reproductive failure. This study assessed the effects of feed containing naturally weathered MPs from the Oslofjord (Norway) on the reproductive physiology of ... -
Evaluering av helse, velferd og tilvekst hos steril laks etter embryonal blokkering av kimcellene
(Research report; Forskningsrapport, 2022-04)Oppdrett av steril laks vil kunne redusere de negative interaksjonene mellom rømt oppdrettslaks og villaks, og dessuten forbedre fiskens velferd og kvalitet. Prosjektets hovedmål har vært å evaluere viktige produksjonsegenskaper hos steril laks etter å ha fjernet de embryonale kimcellene. Inaktivering av kimcellefaktoren Deadend ga livsvarig tap av kjønnsceller hos både hann- og hunnfisk. Steril ... -
Impacts of Early Life Stress on the Methylome and Transcriptome of Atlantic Salmon
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-10)Exposure to environmental stressors during early-life stages can change the rate and timing of various developmental processes. Epigenetic marks affecting transcriptional regulation can be altered by such environmental stimuli. To assess how stress might affect the methylome and transcriptome in salmon, fish were treated using cold-shock and air-exposure from the eye-stage until start-feeding. ... -
Molecular transfer to Atlantic salmon ovulated eggs using liposomes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-15)The delivery of exogenous biomolecules into teleost eggs is currently mostly relying on the manual microinjection methods, which, due to their high costs and low throughput, are not economically feasible for large-scale aquaculture applications. The main objective of this study was to develop a convenient, simple immersion delivery model for unfertilized Atlantic salmon (Salmo salar L.) eggs using ... -
Optimizing intensive culture protocols for Atlantic cod (Gadus morhua) larvae
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-22)Larval cod require live prey as food, and prey concentration (PC) and feeding frequency (FF) often afect their growth and survival. Apart from this, water exchange rates/water fow (WER/WF) and water current (WC) also afect the prey resident time in the tank and larval/early juvenile behaviour, respectively. High water current is also known to induce stress in fnfsh larvae, and this stress response ... -
Production of sterile Atlantic salmon by germ cell ablation with antisense oligonucleotides
(Journal article; Tidsskriftartikkel, 2023)Cultivation of sterile-only fish in aquaculture offers multiple benefits of environmental, economical, and social value. A reliable method for efficient sterilization without affecting fish welfare and performance traits would have significant impact on fish production practices. Here, we demonstrate sterilization of Atlantic salmon embryos by targeting the dead end gene with antisense oligonucleotides. ... -
Sex steroid dynamics and mRNA transcript profiles of growth- and development-related genes during embryogenesis following induced follicular maturation in European eel
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-15)Hormones and mRNA transcripts of maternal origin deposited in the egg may affect early embryonic development in oviparous species. These hormones include steroids, such as estradiol-17β (E2), testosterone (T), 11-ketotestosterone (11-kt), 17α,20ß-dihydroxy-4-pregnen-3-one (DHP), and cortisol, which also play an important role in fish reproduction. In European eel, <i>Anguilla anguilla</i>, which ... -
Ultrasonic imaging as a means of monitoring gonadal development in lumpfish (Cyclopterus lumpus)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-21)The commercial farming of juvenile lumpfish requires monitoring of gonadal development to achieve synchronized production. Conventional methods such as gonadosomatic index (GSI), sex hormone analyses, gonadal histology, endoscopy, and gene expression analyses are costly, invasive, and often involve sacrificing the fish. We assessed the efficiency of ultrasound as a non-invasive method for monitoring ...
