A transcriptomic analysis of diploid and triploid Atlantic salmon lenses with and without cataracts

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, they often show differences in performance, physiology, behavior and morphology compared to diploid fish, with increased prevalence of vertebral deformities and ocular cataracts as two of the most severe disorders. Here, we investigated the mechanisms behind the higher prevalence of cataracts in triploid salmon, by comparing the transcriptional patterns in lenses of diploid and triploid Atlantic salmon, with and without cataracts. We assembled and characterized the Atlantic salmon lens transcriptome and used RNA-seq to search for the molecular basis for cataract development in triploid fish. Transcriptional screening showed only modest differences in lens mRNA levels in diploid and triploid fish, with few uniquely expressed genes. In total, there were 165 differentially expressed genes (DEGs) between the cataractous diploid and triploid lens. Of these, most were expressed at lower levels in triploid fish. Differential expression was observed for genes encoding proteins with known function in the retina (phototransduction) and proteins associated with repair and compensation mechanisms. The results suggest a higher susceptibility to oxidative stress in triploid lenses, and that mechanisms connected to the ability to handle damaged proteins are differentially affected in cataractous lenses from diploid and triploid salmon.publishedVersionUnit Licence Agreemen

A transcriptomic analysis of diploid and triploid Atlantic salmon lenses with and without cataracts

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, they often show differences in performance, physiology, behavior and morphology compared to diploid fish, with increased prevalence of vertebral deformities and ocular cataracts as two of the most severe disorders. Here, we investigated the mechanisms behind the higher prevalence of cataracts in triploid salmon, by comparing the transcriptional patterns in lenses of diploid and triploid Atlantic salmon, with and without cataracts. We assembled and characterized the Atlantic salmon lens transcriptome and used RNA-seq to search for the molecular basis for cataract development in triploid fish. Transcriptional screening showed only modest differences in lens mRNA levels in diploid and triploid fish, with few uniquely expressed genes. In total, there were 165 differentially expressed genes (DEGs) between the cataractous diploid and triploid lens. Of these, most were expressed at lower levels in triploid fish. Differential expression was observed for genes encoding proteins with known function in the retina (phototransduction) and proteins associated with repair and compensation mechanisms. The results suggest a higher susceptibility to oxidative stress in triploid lenses, and that mechanisms connected to the ability to handle damaged proteins are differentially affected in cataractous lenses from diploid and triploid salmon.info:eu-repo/semantics/publishedVersio

A comparison of triploid and diploid Atlantic salmon (Salmo salar) performance and welfare under commercial farming conditions in Norway

Avoiding genetic interactions between wild and farmed Atlantic salmon is regarded as one of the major requirements for a sustainable salmon aquaculture industry. For this reason, farming functional sterile triploids has been suggested as a possible solution. However, knowledge about how triploids cope under commercial conditions is lacking. In the present study, we compared the performance of diploid and triploid Atlantic salmon among four Norwegian aquaculture companies. Diploid and triploid groups of the same genetic line were farmed in western, mid, and northern Norway under commercial conditions from seawater transfer until slaughter.Overall, triploid salmon exhibited reduced survival, higher incidence of emaciated fish, and scored, on average, a lower quality rating during primary processing. The results highlight the need for further research on how to improve the welfare and performance of triploid salmon in commercial aquaculture operations.publishedVersio

Triploid Atlantic salmon, temperature, early development, and the potential for epigenetic programming

Triploidy is the only technique approved for inducing sterility in fish intended for human consumption. To increase the environmental sustainability and public perception of the aquaculture industry, scientific understanding of triploids must increase, assumptions must be challenged, and the additional costs linked with triploid production must be reduced. The gap between triploids and diploids in terms of performance is shrinking, but temperature tolerance remains a significant hurdle. In this thesis we aimed to tackle some of these issues. A suite of microsatellites was developed to verify triploidy, a protocol was established for extracting usable DNA (Deoxyribonucleic acid) from embryos between 26-78 degree days. In combination, these tools can reduce the cost and resources related with triploidy validation. The held assumption that triploids develop at the same rate as diploids during embryogenesis was validated; although differences in the timing of hatch were observed, with triploids hatching earlier. Optimal cleaning solution was determined, providing a useful tool for further studies. Triploidy was shown to have no significant negative impact on health or performance after thermal shocks at around 360 degree days, providing more support for the acceptance of triploids. Triploids performed well incubated at 4°C till eyeing and 6°C until hatch, with only a slight differential in radiological vertebral abnormalities found and no ploidy difference in mortalities or other malformations. Transcriptomic analysis after embryonic thermal shock and during thermal challenge later in life improved scientific understanding of triploids, revealing slight the differences between ploidy. Epigenetic analysis revealed triploids increased variability in the case of DNA methylation patterns. The potential of thermal programming to improve temperature tolerance was first demonstrated in a fish species, with shocked triploids experiencing increased growth under thermal stress. Raising the exciting prospect of not only removing a major barrier in triploid acceptance, but also providing a vital tool as the aquaculture industry faces rising temperatures worldwide

Biological availability of different commercially available histidine products in feed for Atlantic salmon smolt

Postponed access: the file will be accessible after 2022-06-01A comparative nutritional study with post-smolt Atlantic salmon (Salmo salar L.) was performed over six weeks to investigate similarities between three suppliers of synthetic His at two dietary levels in a formulated extruded pellet for salmon, and how they affected feed utilization, fish performance, cataract development, digestibility, and biological efficacy. His source or dietary level of His did not affect feed utilization. Digestibility was similar between all experimental groups and the control group. No difference were found in organ indexes for His source, but the dietary level of His showed reduced growth in organ indexes for high supplementation level versus medium and control. Differences existed between experimental groups and the control group for fish performance, but these were assumed to be non-related to nutrition due to their inconsistency. His supplementation reduced cataract severity, while no difference was found between His sources. Tissue levels of His, anserine and NAH concentrations were similar between His sources.Masteroppgave i fiskehelseFISK399MAMN-FIS

Long term biological effects of ionizing radiation on the eye development in gamma-irradiated Atlantic salmon embryos

Organisms are at their most sensitive to ionizing radiation during the embryonic life stage, and the eye is one of the most sensitive tissues. High proliferation-rate, cell-differentiation and embryonic development depend on intact DNA and other biomolecules. In the present study, eyes of Atlantic salmon (Salmo salar) were studied at the stage of transition between alevin and fry, after a three-month recovery period from exposure to γ-radiation at dose-rates of 1, 10, and 20 mGy/h during the entire embryonic development. Long-term effects on development of eyes were assessed through histological methods, and molecular responses were investigated through immunofluorescence. In addition, effect of ionizing radiation on development of cataract was investigated by use of molecular marker responses. Whole eyes from non-irradiated salmon parr were also dissected and analyzed for documentation of potential effects associated with formalin fixation and its implications for histochemical analysis of eye-globes. Histological analysis of heads from Salmon fry using 3.5 μm thick hematoxylin-eosin (HE) stained sections revealed no significant differences in tissue structure between exposed individuals and the control group, regardless of dose-rate. Extended storage on formalin did not have a negative effect on the outcome of HE-staining, and the tissue showed no apparent artefacts after dissection and dehydration. Prolonged fixation of salmon alevin did not impact the reactivity with immunofluorescent labels. Molecular effects were investigated by staining 3.5 μm paraffin sections with primary antibodies and a rhodamine red fluorescent secondary antibody. Autophagy in the eye was investigated by labeling with microtubule associated protein 1 light chain 3 (LC3), but the marker revealed no significant effect from radiation. Apoptosis and cell-proliferaion were investigated by labeling with Caspase-3, Ki-67 and Anti-Proliferating Cell Nuclear Antigen (PCNA) antibodies respectively, but none of the markers gave detectable levels, most likely due to incompatibility between the antibodies used and Salmo salar as a species. Fibrosis was investigated using α-Smooth Muscle Actin (α-SMA), and despite no visible fibrotic tissue in the eye, elevated levels of the enzyme was found as a response to doses above 10 mGy/h. Oxidative DNA damage was investigated by labeling with 8-hydroxy-2’-deoxyguanosine (8OHdG), 8-oxoguanine-DNA glycosylase (OGG1), Apurinic/apyrimidinic endonuclease 1 (APE1) and anti-DNA polymerase-β for detection of base excision repair (BER) activity. No persistent damage to nuclear DNA was found 3 months after exposure, although detection of cytoplasmic 8OHdG and APE1 suggests damage to mRNA and mitochondrial DNA (mtDNA) independent of dose. Slightly elevated levels of DNA-pol β in the nuclei could be seen in irradiated fish in a dose-dependent manner. Although clinical cataract was not directly assessed, mechanisms associated with developing cataracts were identified. Detection of markers for fibrotic tissue and oxidative damage in the lens and lens-epithelial cells (LECs) increased in a dose dependent manner after exposure to γ-radiation and may suggest a future development of cataracts.Organismer er på sitt mest sårbare for ioniserende stråling i det embryonale livsstadiet, og øyet er et av de mest sensitive organene. Høy celleproliferasjon, celledifferensiering og embryonal utvikling er avhengig av intakt DNA og andre biomolekyler. I det nåværende studiet ble øyer fra atlantisk laks (Salmo salar) studert ved overgangen fra plommesekkyngel til yngel, etter en tre måneders restitueringsperiode fra eksponering med γ-stråling ved doseratene 1, 10 og 20 mGy/h under den embryonale utviklingen. Langtidseffekter på utvikling av øyet ble vurdert gjennom histologiske metoder, og molekylære responser ble undersøkt gjennom immunfluorescens. I tillegg ble effekter knyttet til ioniserende stråling og utvikling av katarakt undersøkt ved bruk av molekylære markører. Hele øyne fra ikke-bestrålte lakse-parr ble også dissekert og undersøkt for dokumentasjon av mulige effekter forbundet med formalin-fiksering og implikasjonene for histokjemisk analyse av øye-globen. Histologisk undersøkelse av hoder fra lakseyngel ved bruk av 3,5 μm tykke haematoxylin-eosine (HE) fargede snitt avslørte ingen signifikante forskjeller i vevsstrukturer mellom eksponerte individer og kontrollgruppen, uavhengig av doserate. Lang lagring på formalin hadde ingen negativ effekt på utfallet av HE-fargningen, og vevet viste ingen åpenbare artefakter etter disseksjon og dehydrering. Forlenget fiksering av lakseyngel hadde heller ingen effekt på reaktiviteten til immunfluoriserende markører. Molekylære effekter ble undersøkt ved å farge 3,5 μm tykke parafinsnitt med primære antistoffer og et rhodamin-rødt fluoriserende sekundært antistoff. Autofagi i øyet ble undersøkt ved merking med mikrotubuli-assosiert protein lettkjede 3 (LC3), men markøren viste ingen signifikant effekt fra stråling. Apoptose og celleproliferasjon ble undersøkt med henholdsvis caspase-3, Ki-67 og antiprolifererende nukleært antigen (PCNA), men ingen av markørene viste sporbare nivåer, mest sannsynlig et resultat av manglende kompatibilitet mellom antistoff og Salmo salar som art. Fibrose ble undersøkt med α-glatt muskel aktin (α-SMA), og økte nivåer av enzymet ble funnet som et resultat av stråling til tross for at fibrose ikke ble observert. Oksidativ DNA-skade ble undersøkt ved å merke prøvene med henholdsvis 8-hydroxy-2’-deoxyguanosie (8OHdG), 8-oxoguanin-DNA glykosylase (OGG1), Apurinisk/apyrimidinsk endonuklease 1 (APE1) og anti-DNA-polymerase β (DNA-pol β) for deteksjon av base-eksisjons-reparasjon (BER) aktivitet. Ingen persistent skade i nukleært DNA ble funnet 3 måneder etter eksponering, men deteksjon av cytoplasmisk 8OHdG og APE1 indikerer skade på mRNA og mitokondrielt DNA (mtDNA) uavhengig av stråledose. Noe forhøyde nivåer av DNA-pol β i cellekjernen kunne observeres i et dose-avhengig forhold i eksponert fisk. Selv om klinisk katarakt ikke ble vurdert direkte, ble mekanismer forbundet med utvikling av katarakt identifisert. Deteksjon av markører for fibrose og oksidativ skade i linsen og linses epitelceller (LECs) økte på en doseavhengig måte etter eksponering med γ-stråling, og kan indikere en fremtidig utvikling av katarakt.M-K

Goods and Services of Marine Bivalves

The aim of this book is to review and analyse the goods and services of bivalve shellfish. How they are defined, what determines the ecological functions that are the basis for the goods and services, what controversies in the use of goods and services exist, and what is needed for sustainable exploitation of bivalves from the perspective of the various stakeholders. The book is focused on the goods and services, and not on impacts of shellfish aquaculture on the benthic environment, or on threats like biotoxins; neither is it a shellfish culture handbook although it can be used in evaluating shellfish culture. The reviews and analysis are based on case studies that exemplify the concept, and show the strengths and weaknesses of the current applications. The multi-authored reviews cover ecological, economic and social aspects of bivalve goods and services. The book provides new insights for scientists, students, shellfish producers, policy advisors, nature conservationists and decision makers. This book is open access under the CC BY license.publishedVersio

A transcriptomic analysis of diploid and triploid Atlantic salmon lenses with and without cataracts

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, they often show differences in performance, physiology, behavior and morphology compared to diploid fish, with increased prevalence of vertebral deformities and ocular cataracts as two of the most severe disorders. Here, we investigated the mechanisms behind the higher prevalence of cataracts in triploid salmon, by comparing the transcriptional patterns in lenses of diploid and triploid Atlantic salmon, with and without cataracts. We assembled and characterized the Atlantic salmon lens transcriptome and used RNA-seq to search for the molecular basis for cataract development in triploid fish. Transcriptional screening showed only modest differences in lens mRNA levels in diploid and triploid fish, with few uniquely expressed genes. In total, there were 165 differentially expressed genes (DEGs) between the cataractous diploid and triploid lens. Of these, most were expressed at lower levels in triploid fish. Differential expression was observed for genes encoding proteins with known function in the retina (phototransduction) and proteins associated with repair and compensation mechanisms. The results suggest a higher susceptibility to oxidative stress in triploid lenses, and that mechanisms connected to the ability to handle damaged proteins are differentially affected in cataractous lenses from diploid and triploid salmon

A transcriptomic analysis of diploid and triploid Atlantic salmon lenses with and without cataracts

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, they often show differences in performance, physiology, behavior and morphology compared to diploid fish, with increased prevalence of vertebral deformities and ocular cataracts as two of the most severe disorders. Here, we investigated the mechanisms behind the higher prevalence of cataracts in triploid salmon, by comparing the transcriptional patterns in lenses of diploid and triploid Atlantic salmon, with and without cataracts. We assembled and characterized the Atlantic salmon lens transcriptome and used RNA-seq to search for the molecular basis for cataract development in triploid fish. Transcriptional screening showed only modest differences in lens mRNA levels in diploid and triploid fish, with few uniquely expressed genes. In total, there were 165 differentially expressed genes (DEGs) between the cataractous diploid and triploid lens. Of these, most were expressed at lower levels in triploid fish. Differential expression was observed for genes encoding proteins with known function in the retina (phototransduction) and proteins associated with repair and compensation mechanisms. The results suggest a higher susceptibility to oxidative stress in triploid lenses, and that mechanisms connected to the ability to handle damaged proteins are differentially affected in cataractous lenses from diploid and triploid salmon

Training Manual In the frame work of the project: DBT sponsored Three Months National Training in Molecular Biology and Biotechnology for Fisheries Professionals 2015-18

This is a limited edition of the CMFRI Training Manual provided to participants of the “DBT sponsored Three Months National Training in Molecular Biology and Biotechnology for Fisheries Professionals” organized by the Marine Biotechnology Division of Central Marine Fisheries Research Institute (CMFRI), from 2nd February 2015 - 31st March 2018