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| 2. |
- Fjelldal, Per Gunnar, et al.
(författare)
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Exogenous growth hormone (GH) increases dimension and reduces strength of vertebrae in Atlantic salmon (Salmo salar)
- 2024
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Ingår i: AQUACULTURE. - 0044-8486 .- 1873-5622. ; 589
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Tidskriftsartikel (refereegranskat)abstract
- Growth hormone (GH) administration increases bone strength in rats, mainly through alterations of the dimensional proportions of vertebrae. However, similar knowledge is lacking in other clades. In order to pursue this, Atlantic salmon were fed diets with high or low vitamin C and E and administered a slow -release implant of bovine GH. While neither the diets or the GH treatment affected growth, GH reduced condition factor and carcass -somatic index, and increased the hepatosomatic and visceral -somatic indexes. GH had an impact on the dimensional proportions of the vertebrae and increased the relative dorso-ventral and lateral vertebra diameters. Moreover, GH decreased the mechanical strength of the vertebra, both with (modulus of elasticity, failure point) and without (stiffness) normalizing the mechanical data for the dimensions of the vertebrae. Diet did not impact on the vertebra morphometry or mechanical strength. RNA-seq of vertebra centra show that several genes associated with bone growth and remodelling were affected by GH, while there was an interactive effect between diet vitamin level and GH on several genes associated with lipid metabolism. The data may suggest that exogenous GH affects the bone cellular mechanisms of Atlantic salmon postsmolts in such a way that their vertebrae increase in diameter but not length, not disturbing growth in body length. The GH and diet effects on lipid metabolism associated genes indicate a complex regulation of the lipids stored inside the vertebral column by endocrine and nutritional factors.
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| 3. |
- Hamre, Bjørn, et al.
(författare)
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Psychiatry in the sorting of schoolchildren in Scandinavia 1920-1950 : IQ testing, child guidance clinics, and hospitalisation
- 2019
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Ingår i: Paedagogica historica. - : Taylor & Francis. - 0030-9230 .- 1477-674X. ; 55:3, s. 391-415
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Tidskriftsartikel (refereegranskat)abstract
- This article explores the role of psychiatry in the sorting of school- children in Denmark, Norway, and Sweden from 1920 to 1950. Whereas the role and rise of educational psychology and IQ-testing in the differentiation processes in schooling have been examined through earlier research, the role of psychiatry in the interprofessional collaboration has so far been largely unexplored when it comes to the Scandinavian case. In line with Michel Foucault, the article regards these professional efforts as part of the biopolitics, where psychiatry amongst other disciplines engaged in the development of means to involve strategically in the life of schoolchildren and their families, as part of shaping the future of the population. We argue that psychiatric sorting activities related to schoolchildren did not solely take place through IQ-testing in schools, but involved classification of children through a range of measures in various settings. We further argue that these processes took place due to local agents and initiatives in a broader context of interprofessional collaborations between psychia- trists, psychologists, and teachers, rather than top–down processes initiated by the state. The analysis in the article draws on different sources of the period: journals, articles, and monographs from the key- agents of the period.
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| 4. |
- Hamre, Bjørn, et al.
(författare)
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The Ascent of Educational Psychology in Denmark in the Interwar Years
- 2014
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Ingår i: Nordic Journal of Educational History. - Umeå : Umeå University Library. - 2001-7766 .- 2001-9076. ; 1:2, s. 87-111
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Tidskriftsartikel (refereegranskat)abstract
- In this article, we argue that an understanding of the interwar years and the ascent of educational psychology contribute valuable knowledge about the inner workings of modern-day education with regard to the links between society and education in general and the boundary between normality and deviation in particular. The establishment of the educational psychologist’s office at Frederiksberg in Denmark, the introduction of IQ testing, and the related psychological files of students provide an image of a period of measurement in schools during which IQ testing was decisive in decisions to transfer students to the remedial school. The testing and filing were the foremost important technologies of the period. We draw on sources that allow us to view educational psychology and testing in their local, national, and political context. The sources applied are primarily obtained from Frederiksberg City Archive that contains archives from the Educational Psychology Office.
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| 5. |
- Ydesen, Christian, et al.
(författare)
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Differentiation of Students in the Early Danish Welfare State : Professional Entanglements Between Educational Psychologists and Psychiatrists
- 2018
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Ingår i: Nordic Journal of Educational History. - Umeå : Umeå University Library. - 2001-7766 .- 2001-9076. ; 5:1, s. 73-96
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Tidskriftsartikel (refereegranskat)abstract
- Historically, numerous contextual factors have influenced the practice of differentiating students. Scholars and practitioners consider it a context-sensitive practice subject to negotiations and entanglements among various agents, groups, interests, ideas, and values. Drawing on Foucault, this article pursues the practices, negotiations, and entanglements surrounding differentiation processes and IQ testing’s use in the early Danish welfare state. We argue that the differentiating practice of IQ testing in the Danish educational system resulted from various factors, including the increasing professionalisation of the educational system. This practice entailed an increased division of labour among professional groups; debates reflecting differing ideas about eugenics, heredity, and social equality; the schooling of psychologists and psychiatrists in Denmark; and the development of psychology and psychiatry as academic disciplines. In that sense, we will demonstrate that changes in society’s understanding of intelligence incorporating a greater use of environmental explanations can be said to reflect the emerging welfare society’s security mechanisms, and a willingness to cope with and address social inequality in an evolving and supposedly universalistic Danish welfare state.
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| 6. |
- Yin, Peng, et al.
(författare)
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Environmentally driven changes in Atlantic salmon oxidative status interact with physiological performance
- 2024
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Ingår i: AQUACULTURE. - 0044-8486 .- 1873-5622. ; 581
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Tidskriftsartikel (refereegranskat)abstract
- Farmed Atlantic salmon in sea cages experience natural seasonal changes in seawater temperature and photoperiod. Atlantic salmon have more oxidized tissues in spring and early summer, and this corresponds to the period of increasing day length, temperature, and growth rate. However, the molecular mechanisms underlying the redox metabolism of Atlantic salmon exposed to the interaction of seasonal cues remain unclear. This study aims to investigate the effect of seasonal changes in temperature and photoperiod on the redox metabolism at the molecular level of Atlantic salmon. Salmon reared in tanks were subjected to simulated natural (for farmed salmon in sea cages) photoperiod and temperature to mimic spring and summer (March to August). We found that the changing photoperiod and temperature, which were simulated to spring and summer conditions, influenced the redox metabolism of Atlantic salmon over the experimental period. We showed that increased utilization of tissue antioxidants such as vitamin C, vitamin E, and reduced glutathione in the spring was restored in August. The more reduced glutathione-based redox potentials and the low levels of malondialdehyde (MDA) in August in liver and muscle suggest lowered tissue oxidative activity at that time. We further revealed that the expression profiles of genes involved in growth hormone signaling and cell cycle regulation were correlated with oxidative stress patterns. Together, these promising results reveal the molecular mechanisms underlying the ecological implications of oxidative status. The study provides new insight into the possible role redox signaling plays in the growth regulation of fish to the seasonal shift in environmental factors.
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| 7. |
- Yin, Peng, et al.
(författare)
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Impact of Antioxidant Feed and Growth Manipulation on the Redox Regulation of Atlantic Salmon Smolts
- 2022
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Ingår i: Antioxidants. - : MDPI AG. - 2076-3921. ; 11:9
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Tidskriftsartikel (refereegranskat)abstract
- 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 dietary antioxidants and growth hormone (GH) on the liver and the muscle redox status of Atlantic salmon. There were two sequential experimental phases (EP) termed EP1 and EP2, each lasting for 6 weeks. In EP1, Atlantic salmon were fed either low-(L, 230 mg/kg ascorbic acid (Asc), 120 mg/kg α-tocopherol (α-TOH)), or high-(H, 380 mg/kg Asc, 210 mg/kg α-TOH)vitamin diets. The vitamins were supplemented as stable forms and the feeding was continued in EP2. In EP2, half of the fish were implanted with 3 μL per g body weight of recombinant bovine GH (Posilac®, 1 mg rbGH g BW−1) suspended in sesame oil, while the other half were held in different tanks and sham-implanted with similar volumes of the sesame oil vehicle. Here, we show that increasing high levels of vitamin C and E (diet H) increased their content in muscle and liver during EP1. GH implantation decreased vitamin C and E levels in both liver and muscle but increased malondialdehyde (MDA) levels only in the liver. GH also affected many genes and pathways of antioxidant enzymes and the redox balance. Among the most consistent were the upregulation of genes coding for the NADPH oxidase family (NOXs) and downregulation of the oxidative stress response transcription factor, nuclear factor-erythroid 2-related factor 2 (nrf2), and its downstream target genes in the liver. We verified that GH increases the growth rate until the end of the trail and induces an oxidative effect in the liver and muscle of Atlantic salmon. Dietary antioxidants do lower oxidative stress but have no effect on the growth rate. The present study is intended as a starting point to understand the potential interactions between growth and redox signaling in fish.
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| 8. |
- Yin, Peng, et al.
(författare)
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Seasonal Changes in Photoperiod: Effects on Growth and Redox Signaling Patterns in Atlantic Salmon Postsmolts
- 2023
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Ingår i: Antioxidants. - 2076-3921. ; 12:8
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Tidskriftsartikel (refereegranskat)abstract
- 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, temperature, or both. The present study examined redox processes in Atlantic salmon that were reared in indoor tanks at constant temperature (9 °C) under a simulated natural photoperiod. The experiment lasted for 6 months, from vernal to autumnal equinoxes, with the associated increase and subsequent decrease in day length. We found that intracellular antioxidants were depleted, and there was an increase in malondialdehyde (MDA) levels in the liver and muscle of Atlantic salmon with increasing day length. Antioxidant enzyme activity in liver and muscle and their related gene profiles was also affected, with a distinct upregulation of genes involved in maintaining redox homeostasis, such as peroxiredoxins in the brain in April. This study also revealed a nuclear factor-erythroid 2-related factor 2 (Nrf2)-mediated oxidative stress response in muscle and liver, suggesting that fish integrate environmental signals through redox signaling pathways. Furthermore, growth and expression profiles implicated in growth hormone (GH) signaling and cell cycle regulation coincided with stress patterns. The results demonstrate that a change in photoperiod without the concomitant increase in temperature is sufficient to stimulate growth and change the tissue oxidative state in Atlantic salmon during spring and early summer. These findings provide new insights into redox regulation mechanisms underlying the response to the changing photoperiod, and highlight a link between oxidative status and physiological function.
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