Changes in circulating insulin-like growth factor-1 and its binding proteins in yearling rainbow trout during spring under natural and manipulated photoperiods and their relationships with gill Na, K-ATPase and body size.

Smoltification in salmonids occurs during spring in response to increasing photoperiod to prepare for marine life. Smoltification is associated with increased hypo-osmoregulatory ability and enhanced growth potential, mediated by growth hormone and insulin-like growth factor (IGF)-1. Rainbow trout is uniquely insensitive to the induction of smoltification-associated changes by photoperiod, such as the activation of gill Na,K-ATPase (NKA).

Neural activation in photosensitive brain regions of Atlantic salmon (Salmo salar) after light stimulation.

Photoreceptive inputs to the teleost brain are perceived as image of the visual world and as photo-modulation of neuroendocrine and neuronal signals. The retina and pineal organ are major receptive organs with projections to various parts of the brain, but in the past decades deep brain photoreceptors have emerged as candidates for photoreceptive inputs, either independent or in combination with projections from light sensory organs. This study aimed to test the effects of narrow bandwidth light using light-emitting diodes technology on brain neural activity through putative opsin stimulation in Atlantic salmon.

Effects of environmental enrichment on forebrain neural plasticity and survival success of stocked Atlantic salmon.

Fish reared for stocking programmes are severely stimulus deprived compared with their wild conspecifics raised under natural conditions. This leads to reduced behavioural plasticity and low post-release survival of stocked fish. Environmental enrichment can have positive effects on important life skills, such as predator avoidance and foraging behaviour, but the neural mechanisms underpinning these behavioural changes are still largely unknown.

Phylogenetic Reclassification of Vertebrate Melatonin Receptors To Include Mel1d.

The circadian and seasonal actions of melatonin are mediated by high affinity G-protein coupled receptors (melatonin receptors, MTRs), classified into phylogenetically distinct subtypes based on sequence divergence and pharmacological characteristics. Three vertebrate MTR subtypes are currently described: MT1 (MTNR1A), MT2 (MTNR1B), and Mel1c (MTNR1C / GPR50), which exhibit distinct affinities, tissue distributions and signaling properties. We present phylogenetic and comparative genomic analyses supporting a revised classification of the vertebrate MTR family.

Proactive avoidance behaviour and pace-of-life syndrome in Atlantic salmon.

Individuals in a fish population differ in key life-history traits such as growth rate and body size. This raises the question of whether such traits cluster along a fast-slow growth continuum according to a pace-of-life syndrome (POLS). Fish species like salmonids may develop a bimodal size distribution, providing an opportunity to study the relationships between individual growth and behavioural responsiveness.

Transient photoreception in the hindbrain is permissive to the life history transition of hatching in Atlantic halibut.

In nonmammalian vertebrates, photoreception takes place in the deep brain already early in development, but knowledge is lacking about the functions of these nonvisual photoreceptive systems. Prior to hatching, Atlantic halibut has a transient bilateral cluster of photoreceptive cells in the hindbrain. The cluster is imbedded in a neuronal network projecting to the narrow belt of hatching glands in the yolk sac.

Allostatic Load and Stress Physiology in European Seabass ( L.) and Gilthead Seabream ( L.).

The present study aimed to compare effects of increasing chronic stress load on the stress response of European seabass () and gilthead seabream () to identify neuroendocrine functions that regulate this response. Fish were left undisturbed (controls) or exposed to three levels of chronic stress for 3 weeks and then subjected to an acute stress test (ACT). Chronic stress impeded growth and decreased feed consumption in seabass, not in seabream.

Comparison between Atlantic salmon Salmo salar post-smolts reared in open sea cages and in the Preline raceway semi-closed containment aquaculture system.

The use of closed containment (CCS) or semi-closed containment systems (S-CCS) for Atlantic salmon Salmo salar aquaculture is under evaluation in Norway. One such system is the Preline S-CCS, a floating raceway system that pumps water from 35 m depth creating a constant current through the system. Exposing fish to moderate water currents is considered aerobic exercise and it is often perceived as positive for fish welfare, growth, food utilization, muscle development and cardiac health.

Early life stress induces long-term changes in limbic areas of a teleost fish: the role of catecholamine systems in stress coping.

Early life stress (ELS) shapes the way individuals cope with future situations. Animals use cognitive flexibility to cope with their ever-changing environment and this is mainly processed in forebrain areas. We investigated the performance of juvenile gilthead seabream, previously subjected to an ELS regime.

How do individuals cope with stress? Behavioural, physiological and neuronal differences between proactive and reactive coping styles in fish.

Despite the use of fish models to study human mental disorders and dysfunctions, knowledge of regional telencephalic responses in non-mammalian vertebrates expressing alternative stress coping styles is poor. As perception of salient stimuli associated with stress coping in mammals is mainly under forebrain limbic control, we tested region-specific forebrain neural (i.e.

The Ontogeny and Brain Distribution Dynamics of the Appetite Regulators NPY, CART and pOX in Larval Atlantic Cod (Gadus morhua L.).

Similar to many marine teleost species, Atlantic cod undergo remarkable physiological changes during the early life stages with concurrent and profound changes in feeding biology and ecology. In contrast to the digestive system, very little is known about the ontogeny and the localization of the centers that control appetite and feed ingestion in the developing brain of fish. We examined the expression patterns of three appetite regulating factors (orexigenic: neuropeptide Y, NPY; prepro-orexin, pOX and anorexigenic: cocaine- and amphetamine-regulated transcript, CART) in discrete brain regions of developing Atlantic cod using chromogenic and double fluorescent in situ hybridization.

Effects of Two Sublethal Concentrations of Mercury Chloride on the Morphology and Metallothionein Activity in the Liver of Zebrafish (Danio rerio).

Mercury (Hg) is a highly hazardous pollutant widely used in industrial, pharmaceutical and agricultural fields. Mercury is found in the environment in several forms, elemental, inorganic (iHg) and organic, all of which are toxic. Considering that the liver is the organ primarily involved in the regulation of metabolic pathways, homeostasis and detoxification we investigated the morphological and ultrastructural effects in Danio rerio liver after 96 h exposure to two low HgCl₂ concentrations (7.

A comparative study of the response to repeated chasing stress in Atlantic salmon (Salmo salar L.) parr and post-smolts.

When Atlantic salmon parr migrate from fresh water towards the sea, they undergo extensive morphological, neural, physiological and behavioural changes. Such changes have the potential to affect their responsiveness to various environmental factors that impose stress. In this study we compared the stress responses in parr and post-smolt salmon following exposure to repeated chasing stress (RCS) for three weeks.

Fatty acids linked to cardiovascular mortality are associated with risk factors.

Background: Although saturated fatty acids (FAs) have been linked to cardiovascular mortality, it is not clear whether this outcome is attributable solely to their effects on low-density lipoprotein cholesterol (LDL-C) or whether other risk factors are also associated with FAs. The Western Alaskan Native population, with its rapidly changing lifestyles, shift in diet from unsaturated to saturated fatty acids and dramatic increase in cardiovascular disease (CVD), presents an opportunity to elucidate any associations between specific FAs and known CVD risk factors.

Objective: We tested the hypothesis that the specific FAs previously identified as related to CVD mortality are also associated with individual CVD risk factors.

Stress in Atlantic salmon: response to unpredictable chronic stress.

Combinations of stressors occur regularly throughout an animal's life, especially in agriculture and aquaculture settings. If an animal fails to acclimate to these stressors, stress becomes chronic, and a condition of allostatic overload arises with negative results for animal welfare. In the current study, we describe effects of exposing Atlantic salmon parr to an unpredictable chronic stressor (UCS) paradigm for 3 weeks.

Functional divergence of type 2 deiodinase paralogs in the Atlantic salmon.

Thyroid hormone (TH) is an ancestral signal linked to seasonal life history transitions throughout vertebrates. TH action depends upon tissue-localized regulation of levels of active TH (triiodothyronine, T3), through spatiotemporal expression of thyroid hormone deiodinase (dio) genes. We investigated the dio gene family in juvenile Atlantic salmon (Salmo salar) parr, which prepare for seaward migration in the spring (smoltification) through TH-dependent changes in physiology.

Apolipoprotein E isoforms 3/3 and 3/4 differentially interact with circulating stearic, palmitic, and oleic fatty acids and lipid levels in Alaskan Natives.

Lifestyle changes in Alaskan Natives have been related to the increase of cardiovascular disease and metabolic syndrome in the last decades. Variation of the apolipoprotein E (Apo E) genotype may contribute to the diverse response to diet in lipid metabolism and influence the association between fatty acids in plasma and risk factors for cardiovascular disease. The aim of this investigation was to analyze the interaction between Apo E isoforms and plasma fatty acids, influencing phenotypes related to metabolic diseases in Alaskan Natives.

The effects of environmental enrichment and age-related differences on inhibitory avoidance in zebrafish (Danio rerio Hamilton).

The inhibitory avoidance paradigm allows the study of mechanisms underlying learning and memory formation in zebrafish (Danio rerio Hamilton). For zebrafish, the physiology and behavior associated with this paradigm are as yet poorly understood. We therefore assessed the effects of environmental enrichment and fish age on inhibitory avoidance learning.

Early steps in the European eel (Anguilla anguilla)-Vibrio vulnificus interaction in the gills: role of the RtxA13 toxin.

Vibrio vulnificus is an aquatic gram-negative bacterium that causes a systemic disease in eels called warm-water vibriosis. Natural disease occurs via water born infection; bacteria attach to the gills (the main portal of entry) and spread to the internal organs through the bloodstream, provoking host death by haemorrhagic septicaemia. V.

Unpredictable chronic stress decreases inhibitory avoidance learning in Tuebingen long-fin zebrafish: stronger effects in the resting phase than in the active phase.

Zebrafish (Danio rerio Hamilton) are increasingly used as a model to study the effects of chronic stress on brain and behaviour. In rodents, unpredictable chronic stress (UCS) has a stronger effect on physiology and behaviour during the active phase than during the resting phase. Here, we applied UCS during the daytime (active phase) for 7 and 14 days or during the night-time (resting phase) for 7 nights in an in-house-reared Tuebingen long-fin (TLF) zebrafish strain.

Exorhodopsin and melanopsin systems in the pineal complex and brain at early developmental stages of Atlantic halibut (Hippoglossus hippoglossus).

The complexity of the nonvisual photoreception systems in teleosts has just started to be appreciated, with colocalization of multiple photoreceptor types with unresolved functions. Here we describe an intricate expression pattern of melanopsins in early life stages of the marine flat fish Atlantic halibut (Hippoglossus hippoglossus), a period when the unpigmented brain is directly exposed to environmental photons. We show a refined and extensive expression of melanopsins in the halibut brain already at the time of hatching, long before the eyes are functional.

Atlantic salmon (Salmo salar L.) smolts require more than two weeks to recover from acidic water and aluminium exposure.

The detrimental effects of acid rain and aluminium (Al) on salmonids have been extensively studied, yet knowledge about the extent and rate of potential recovery after exposures to acid and Al episodes is limited. Atlantic salmon smolts in freshwater (FW) were exposed for 2 and 7-day episodes (ACID2 and ACID7, respectively) to low pH (5.7±0.

Environmental enrichment promotes neural plasticity and cognitive ability in fish.

Different kinds of experience during early life can play a significant role in the development of an animal's behavioural phenotype. In natural contexts, this influences behaviours from anti-predator responses to navigation abilities. By contrast, for animals reared in captive environments, the homogeneous nature of their experience tends to reduce behavioural flexibility.

Isolation and characterization of melanopsin photoreceptors of Atlantic salmon (Salmo salar).

Melanopsins constitute a recently described group of vertebrate opsin photoreceptors that are involved in nonvisual photoreception. Here we describe the identification of six melanopsin genes of Atlantic salmon (Salmo salar), a valuable teleost model for studying nonvisual photoreception and the basis of photoperiodism. The results show that genes belonging to two different groups, the mammalian-like (Opn4m) and the Xenopus-like (Opn4x) melanopsins have been duplicated in teleosts.

Heart rate is associated with markers of fatty acid desaturation: the GOCADAN study.

Objectives: To determine if heart rate (HR) is associated with desaturation indexes as HR is associated with arrhythmia and sudden death.

Study Design: A community based cross-sectional study of 1214 Alaskan Inuit.

Methods: Data of FA concentrations from plasma and red blood cell membranes from those ≥35 years of age (n = 819) were compared to basal HR at the time of examination.