The effect of electric pulse stimulation to juvenile cod and cod of commercial landing size

The first pilot study on the effects of electric pulse stimulation on larger cod carried out in 2008 was based on a single nominal setting of the Verburg-Holland UK153 pulse system with the intention to determine the range of pulse characteristics with which injuries to the fish occurred. This study was designed to obtain a more detailed view on the effects of the pulse characteristics and to investigate if a specific pulse parameter has a key role in the effects. Lower pulse amplitudes with longer pulse width and higher frequency could induce different effects than pulses with higher amplitudes, shorter pulse width and lower frequency. In this way the effects can be related to a specific pulse parameter and its threshold value. Another aim of major importance is that this research also carried out on the electrically exposed fish that would normally escape through the cod-end meshes with unknown longer term effects. This was already recommended after the first experiment in 2008

Deformacije glave uzgojenog triploidnog bakalara, Gadus morhua Linnaeus, 1758 (Actinopterygii: Gadiformes: Gadidae) u Norveškoj

A farmed triploid pug-headed specimen of the Atlantic cod, Gadus morhua measuring 501 mm TL was obtained from IMR Parisvatn Field Station, Norway. The abnormal specimen had the following aberrant characters: short neurocranium and upper jaw, very short snout in comparison with the normal specimens, and asymmetrical upper and lower jaws. The right side of the head and the pre-maxilla were deformed, twisted downward and forward. The lower jaw was slightly distorted to the left. Causes for such aberrations are discussed.Uzgojeni triploidni primjerak bakalara, Gadus morhua, s deformacijom glave, ukupne duljine 501 mm je ulovljen u blizini Instituta za istraživanje mora kod Parisvatn terenske postaje u Norveškoj.Abnormalni primjerak je imao sljedeće neprirodne znakove: kratki neurokranij (koštani pokrov mozga), i gornja čeljust, vrlo kratka gubica u usporedbi s normalnim primjercima, te asimetrična gornja i donja čeljust. Desna strana glave i gornja vilica (premaxilla) su deformirani, izvrnute su prema dolje i naprijed. Donja vilica je blago iskrivljena ulijevo. U radu se raspravlja o uzrocima takvih odstupanja

Effects of laboratory salmon louse infection on osmoregulation, growth and survival in Atlantic salmon

Anadromous Atlantic salmon (Salmo salar) rely on long ocean migrations to build energy stores for maturation and spawning. In seawater, wild Atlantic salmon are threatened by high salmon lice (Lepeophtheirus salmonis) infestation levels resulting from intensive salmonid sea-cage aquaculture. Salmon lice infection can cause a stress response and an osmotic imbalance in the host. The lice infection intensity threshold values for these responses, however, remain to be identified in Atlantic salmon. In order to define this under laboratory conditions, individually tagged F1 wild origin Atlantic post-smolts (40 g) were infected with salmon lice copepodids or left as uninfected controls. Twenty-eight days post infection, infected post-smolts had a mean of 0.38 (range of 0.07–0.9) mobile lice g−1 fish weight. During this period, specific growth rates (SGRs) were lower in infected than control fish (0.4 vs 1.0% day−1). Higher plasma Na+, Cl− and osmolality in infected fish also indicate osmoregulatory impairment. SGR correlated negatively with plasma Na+, Cl−, osmolality and cortisol in the infected, but not in the control group. Infection intensity (lice g−1 fish) correlated positively with mortality rate and plasma Na+, Cl−, osmolality and cortisol and correlated negatively with SGR and condition factor. Calculated lice intensity threshold values for changes in plasma ions were 0.18 lice g−1 for plasma Cl−, and 0.22 lice g−1 for plasma Na+. Moribund infected fish occurred at infection intensities above 0.2 lice g−1, and these fish had extreme plasma Cl−, Na+, osmolality and cortisol levels. There was a positive correlation between plasma cortisol and plasma Na+, Cl− and osmolality in infected fish. This study provides vital information that can be used to define thresholds in the monitoring and conservation of wild Atlantic salmon populations affected by aquaculture-driven salmon lice infestations.publishedVersio

Environmental and Genetic (vgll3) Effects on the Prevalence of Male Maturation Phenotypes in Domesticated Atlantic Salmon

Pre-harvest male maturation is problematic for Atlantic salmon (Salmo salar) farmers and is regulated by the environment and genetics (e.g., vgll3). Five families of all-male salmon parr (produced using YY males crossed with XX females) with different vgll3 genotypes were split between three environmental regimes in January 2018. The “advanced maturation” regime used elevated temperature (16 °C) and continuous light from January 2018 with post-smolt maturation assessed in March 2018. The “extended freshwater” regime used ambient freshwater (1–16 °C) and simulated natural photoperiod (SNP) with post-smolt maturation assessed in November 2018. The “sea transfer” regime used ambient temperatures (1–14 °C) and SNP in freshwater until May 2018 when they were transferred to 9 °C seawater with natural photoperiod for 2.5 years (final mean weight of circa. 14 kg) and assessed for post-smolt maturation, 1 sea-winter (1 SW) maturation, and 2 sea-winter (2 SW) maturation in the autumn (November/December) of 2018, 2019, and 2020, respectively. Post-smolt maturation was highest in the advanced maturation and extended freshwater regimes (39–99% depending on family) and lowest in the sea transfer regime (0–95% depending on family). In the sea transfer regime, maturity incidence increased over time (0–95% post-smolt maturation, 1–100% 1 SW, and 50–90% 2 SW maturation, depending on family). In all regimes, those homozygous for the pre-designated vgll3 “early” maturing allele had the highest incidences of maturation whilst those homozygous for the “late” allele had the lowest. A low percentage of 2 SW phenotypic and genetic females were found (0–5% depending on family), one of which was successfully crossed with an XY male resulting in progeny with an approx. 50/50 sex ratio. These results show (i) post-smolt maturation varies dramatically depending on environment although genetic regulation by vgll3 was as expected, and (ii) crossing YY sperm with XX eggs can result in XX progeny which can themselves produce viable progeny with an equal sex ratio when crossed with an XY male.publishedVersio

Logopeders erfaringer med behandlingstilnærming for personer med Exercise Induced Laryngeal Obstruction/EILO

Masteroppgave i logopedi - Nord universitet, 201

Epithelial label-retaining cells are absent during tooth cycling in <i>Salmo salar</i> and <i>Polypterus senegalus</i>

The Atlantic salmon (Salmo salar) and African bichir (Polypterus senegalus) are both actinopterygian fish species that continuously replace their teeth without the involvement of a successional dental lamina. Instead, they share the presence of a middle dental epithelium: an epithelial tier enclosed by inner and outer dental epithelium. It has been hypothesized that this tier could functionally substitute for a successional dental lamina and might be a potential niche to house epithelial stem cells involved in tooth cycling. Therefore, in this study we performed a BrdU pulse chase experiment on both species to (1) determine the localization and extent of proliferating cells in the dental epithelial layers, (2) describe cell dynamics and (3) investigate if label-retaining cells are present, suggestive for the putative presence of stem cells. Cells proliferate in the middle dental epithelium, outer dental epithelium and cervical loop at the lingual side of the dental organ to form a new tooth germ. Using long chase times, both in S. salar (eight weeks) and P. senegalus (eight weeks and twelve weeks), we could not reveal the presence of label-retaining cells in the dental organ. Immunostaining of P. senegalus dental organs for the transcription factor Sox2, often used as a stem cell marker, labelled cells in the zone of outer dental epithelium which grades into the oral epithelium (ODE transition zone) and the inner dental epithelium of a successor only. The location of Sox2 distribution does not provide evidence for epithelial stem cells in the dental organ and, more specifically, in the middle dental epithelium. Comparison of S. salar and P. senegalus reveals shared traits in tooth cycling and thus advances our understanding of the developmental mechanism that ensures lifelong replacement

An analysis of Norwegian public health nursing curricula: Where is the nursing literature?

Background - Norwegian public health nurses prevent diseases and promote health in children and young people aged 0–20 and their families. Public health nursing programs prepare students for their practical role and provide relevant theoretical knowledge. Objectives - To gain knowledge of the literature in the Norwegian public health nursing curricula, and to examine further the nursing base in these curricula. Design - An explorative and descriptive design was chosen. Sample - Reading lists based on syllabus documents from the 10 higher educational institutions in Norway offering programs in public health nursing. Measurements - A summative content analysis and a categorization of content from reading lists were performed. Results - Numerical information on the content and categorization of reading lists shows that social science and humanities literature dominates, followed by psychology and medicine. Nursing texts, theories and philosophy comprise only a minor part of the curricula. Conclusion - The paper provides valuable data on the theoretical focus in Norwegian public health nursing and raises important questions about the paucity of nursing texts in the curriculum. The imbalance in reading lists in Norway should be studied further and similar studies conducted in other countries to encourage reflection on the theoretical content of public health nursing education globally

Vertebral deformities in interspecific diploid and triploid salmonid hybrids

publishedVersio