Browsing by Author "Hamre, K."
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- Dietary beauvericin and enniatin B exposure cause different adverse health effects in farmed Atlantic salmonPublication . Berntssen, M. H. G.; Fjeldal, P. G.; Gavaia, Paulo; Laizé, Vincent; Hamre, K.; Donald, C. E.; Jakobsen, J. V.; Omdal, Å.; Søderstrøm, S.; Lie, K. K.The extensive use of plant ingredients in novel aquafeeds have introduced mycotoxins to the farming of seafood. The emerging enniatin B (ENNB) and beauvericin (BEA) mycotoxins have been found in the novel aquafeeds and farmed fish. Little is known about the potential toxicity of ENNs and BEA in farmed fish and their feed-to-organ transfer. Atlantic salmon (Salmo salar) presmolt (75.3 +/- 8.10 g) were fed four graded levels of spiked chemical pure ENNB or BEA feeds for three months, in triplicate tanks. Organismal adverse health end-point assessment included intestinal function (protein digestibility), disturbed hematology (red blood cell formation), bone formation (spinal deformity), overall energy use (feed utilization), and lipid oxidative status (vitamin E). Both dietary BEA and ENNB had a low ( liver > brain > muscle), with a higher transfer for ENNB compared to BEA. BEA caused a growth reduction combined with a decreased protein digestion and feed conversion rate-ENNB caused a stunted growth, unrelated to feed utilization capacity. In addition, ENNB caused anemia while BEA gave an oxidative stress response. Lower bench-mark dose regression assessment showed that high background levels of ENNB in commercial salmon feed could pose a risk for animal health, but not in the case of BEA.
- Effects of phylloquinone on Solea senegalensis skeletogenesisPublication . Gavaia, Paulo J.; Dionísio, Gisela; Conceição, L. E. C.; Hamre, K.; Cancela, LeonorSkeletogenesis is a continuous process occurring during fish larval development that is influenced by vitamin K VK, an essential factor for the correct formation of coagulation factors and skeletal matrix proteins. High levels of skeletal deformities are recorded in most commonly cultured species like the sparids, sea bass and flatfish like the Senegalese sole. The appearance of malformations takes place during the larval stages, when skeletal structures are forming.
- Fish Larval Research: a tool for sustainable food production and understanding environmental impacts on developing organismsPublication . Pittman, K.; Rønnestad, I.; Gavaia, Paulo J.; Cancela, Leonor; Guerreiro, P. M.; Ribeiro, Laura; Aragão, C.; Hamre, K.; Moren, M.; Yúfera, M.; Conceição, L. E. C.Reliable juvenile production or recruitment requires high numbers of healthy fish larvae. Despite considerable progress in marine fish farming in the past 20 years, juvenile fish production is still fraught with problems which arise during the larval phase. In fisheries, juvenile recruitment in some populations has not recovered despite long-term moratoria on captures and protection of the broodstock. These issues highlight the growing importance of multidisciplinary fish larval research.
- Staging of Atlantic halibut (Hippoglossus hippoglossus L.) from first feeding through metamorphosis, including cranial ossification independent of eye migrationPublication . Sæle, Ø.; Solbakken, J. S.; Watanabe, K.; Hamre, K.; Power, Deborah; Pittman, K.To determine developmental stages independent of eye migration, a highly plastic feature in Atlantic halibut, 180 sibling halibut larvae reared at an average temperature of 11.9 jC from first feeding and for a further 46 days were examined, cleared and stained for ossification and the cranial development was recorded. Morphological development and cranial ossification generally coincided. The order of ossification of cranial structures was: jaw structures, hyoid arch, opercular bones and structures of the neurocranium. The Frontale exhibited torsion correlated with eye migration, but calcification began earlier and full calcification was independent of ocular displacement. The appearance of ossified elements was used to group larvae into Stages 5–9, comprising premetamorphosis to climax metamorphosis, with significant morphometric differences between stages. The trajectory of juvenile development appears fixed by Stage 8. There was a linear relationship between stage and myotome height (R2 = 0.86) and stage and standard length (R2 = 0.80). The stage definitions were validated on two groups (n = 23, n = 101) of commercially produced larvae. Because metamorphosis is protracted in halibut, use of these stages and especially myotome height should help standardize sampling and analysis between experiments and between producers.