Marit Skog Eriksen

Ane Skjelfjord

How does stress during pregnancy affect the offspring?

Embryonic exposure to glucocorticoids and its impact on developmental trajectories - with particular emphasis on farmed Atlantic salmon (Salmo salar)

Stressful experiences are an inevitable fact of life for most creatures. In mammals and birds a major mechanism of the stress response involves the HPA-system, or in teleosts; the equivalent HPI-axis, which may ultimately result in increased secretion of glucocorticoids. Glucocorticoids are functional in that they may prepare the organism for an energy-demanding attempt to thwart the effects of the perceived stressor and maintain homeostasis. Yet, in situations where the organism has poor or no control over its challenges, the stress response could endure, which might subsequently increase susceptibility to physiological pathologies like growth inhibition and reproductive detriments. In many farmed species the brood stock are kept under conditions that could provoke stress for the animals. During the last decades a substantial body of evidence, mainly from mammals, has demonstrated that stressors encountered during pregnancy have the capacity to exert profound and permanent impacts on various physiological, morphological and behavioural characteristics of the progeny. Maternal glucocorticoids are shown to be central in mediating the effects of prenatal stress.

In birds and fish the significance of the prenatal environment has received limited attention. Thus the primary objective of the present work was to test the hypothesis that prenatal exposure to glucocorticoids affects developmental trajectories in poultry (Gallus gallus domesticus) and farmed Atlantic salmon (Salmo salar) juveniles. We manipulated the levels of glucocorticoids in fertilized poultry eggs and in mature salmon females. Several aspects of offspring characters were studied; still, particular emphasis was put on developmental stability. In general we found that excess glucocorticoids affected survival rates, growth patterns, fluctuating asymmetry and frequency of malformations. In salmon, embryonic exposure to glucocorticoids influenced the capability to cope with an additional stressor and also impinged on the behavioural responses when exposed to a novel environment. Although the results obtained in this thesis were multifaceted, they indicate that developmental trajectories of the progeny may be significantly altered if levels of glucocorticoids are elevated in females during gametogenesis. Overall, these findings may be important both from a fundamental point of view, but also owing to their possible relevance for production animals because they unveil mechanisms that can plausibly link maternal factors to offspring viability and productivity.

ISI database key words: feather pecking; laying hens; stress; behavior; rats; instability; stability; differentiation; secretion; pollution; trout oncorhynchus-mykiss; pituitary-adrenal axis; dicentrarchus-labrax l; prenatal stress; rainbow-trout; adult-rats; reproductive-performance; plasma-corticosterone; sea bass; quality; brood stock; cortisol; hyperthermia; malformations; growth; salmon; developmental stability; prenatal stress; cortisol; aquaculture; welfare; Atlantic salmon

Nøkkelord til artikkelsøk: fjørhakking; høns; høne; rugehøne; stress; adferd; atferd; rotter; sekresjon; forurensning; kortikosteron; kortisol; vekst; dyrevelferd; velferd; fisk; ørret; laks; misdannelser; akvakultur

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Oppdatert: 19.09.06
Utskriftsvennlig versjon : Arkiv : Tips en venn