scholarly journals A novel emotional and cognitive approach to welfare phenotyping in rainbow trout exposed to poor water quality

2018 ◽  
Author(s):  
V Colson ◽  
A Mure ◽  
C Valotaire ◽  
JM Le Calvez ◽  
L Goardon ◽  
...  
Keyword(s):  
Water Quality ◽  
Rainbow Trout ◽  
Social Isolation ◽  
Plasma Cortisol ◽  
Fish Welfare ◽  
Cognitive Approach ◽  
Human Presence ◽  
Novel Environment ◽  
Poor Water Quality ◽  
Cortisol Levels

AbstractRecent scientific evidence for fish sentience has stressed the need for novel sentience-based detection tools of fish welfare impairment in commercial farms. In order to mimic a well-characterised stress situation, rainbow trout (Oncorhynchus mykiss) were exposed to poor water quality (hypoxia combined with high ammonia level) for three weeks (stressed group, S) and compared to a non-stressed control group (NS). After a return to water quality standard, emotional responses were assessed in fish subjected to two potentially threatening situations: (i) social isolation in a novel environment and (ii) human presence. In addition, we used an appetitive-conditioning paradigm to determine whether previous chronic deterioration of water quality disturbs cognitive abilities in fish. Spontaneous behaviour in the tanks was also recorded during the environmental challenge as a reference for fish activity. We observed that in S fish, plasma cortisol levels were increased before and after social isolation in a novel environment compared to the plasma cortisol levels in the NS group, despite the absence of a behavioural difference between the two groups. Under deteriorated water quality, fish locomotor activity was globally reduced and this reduction was correlated to increased shoaling behaviour. Farmers can use these first behavioural modifications as a sentinel detector for fish welfare impairment. More importantly, we demonstrated that reactivity to a human presence in a home-environment and food-anticipatory behaviour were both inhibited in the S group. We consider that these two sentience-based tests are highly relevant for fish welfare assessment at the group level and are easy to use in the aquaculture industry.

scholarly journals A novel emotional and cognitive approach to welfare phenotyping in rainbow trout exposed to poor water quality

2019 ◽  
Vol 210 ◽  
pp. 103-112 ◽  
Author(s):  
V. Colson ◽  
A. Mure ◽  
C. Valotaire ◽  
J.M. Le Calvez ◽  
L. Goardon ◽  
...  
Keyword(s):  
Water Quality ◽  
Rainbow Trout ◽  
Cognitive Approach ◽  
Poor Water Quality

Hatchery tank enrichment affects cortisol levels and shelter-seeking in Atlantic salmon (Salmo salar)

2013 ◽  
Vol 70 (4) ◽  
pp. 585-590 ◽  
Author(s):  
Joacim Näslund ◽  
Malin Rosengren ◽  
Diego Del Villar ◽  
Lars Gansel ◽  
Johnny R. Norrgård ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Plasma Cortisol ◽  
Natural Populations ◽  
Fish Welfare ◽  
Plastic Tube ◽  
Atlantic Salmon Salmo Salar ◽  
Basal Plasma ◽  
Cortisol Levels ◽  
The Impact

Stocking programs using hatchery-reared salmon are often implemented for augmenting natural populations. However, survival of these fish is often low compared with wild conspecifics, possibly because of genetic, physiological, and behavioural deficiencies. Here, we compared presmolt Atlantic salmon (Salmo salar) from three different environmental treatments (barren environment, plastic tube enrichment, and plastic shredding enrichment) with regard to plasma cortisol levels, shelter-seeking behaviour, and fin deterioration. Basal plasma cortisol levels were higher in barren-reared fish, indicating higher stress levels, while no differences were found in acute cortisol response after a 30 min confinement test. Shelter-seeking was higher in salmon reared in enriched tanks when tested alone, but not when tested in small groups. Barren-reared fish had higher levels of fin deterioration over winter, potentially owing to higher aggression levels. These results suggest that enrichment can reduce the impact of stressors experienced in the hatchery and thus increase fish welfare. Tank enrichment may also be used to produce salmon better adapted for the more complex environment encountered after release.

scholarly journals Elevation of plasma somatolactin concentrations during acidosis in rainbow trout (Oncorhynchus mykiss)

1996 ◽  
Vol 199 (5) ◽  
pp. 1043-1051 ◽  
Author(s):  
S Kakizawa ◽  
T Kaneko ◽  
T Hirano
Keyword(s):  
Rainbow Trout ◽  
Plasma Cortisol ◽  
Initial Level ◽  
Plasma Concentrations ◽  
Water Acidification ◽  
Acid Base ◽  
Exposed Fish ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Blood Ph ◽  
Cortisol Levels

Somatolactin (SL) is a putative pituitary hormone of the growth hormone (GH)/prolactin (PRL) family in fish; its physiological function has yet to be determined. Acidosis was induced in rainbow trout (Oncorhynchus mykiss) by exposure to acidic water (pH 4.5) or by exhaustive exercise, and plasma concentrations of SL, PRL and GH as well as other plasma parameters were examined. A decrease in blood pH was observed in fish from 1 day after water acidification until the end of the experiment at day 7. Plasma SL levels in the acid-exposed fish increased, reached a peak on day 1 and then returned to the initial level by day 4. No change was seen in plasma concentrations of PRL throughout the experiment. Plasma levels of GH, in contrast, decreased in the acid-exposed fish on days 2 and 4. Plasma cortisol levels in the acid-exposed fish were higher than the control level on days 4 and 7, although plasma cortisol levels did not increase above the initial level in response to water acidification. There was no significant change in the expression of SL-, PRL- and GH-mRNA in the pituitary gland. Levels of plasma Na+ and lactate were reduced 12 h after water acidification and remained low throughout the experiment. Exhaustive exercise in shallow water at neutral pH (7.5) resulted in a transient but pronounced acidosis, associated with increases in plasma SL, cortisol, Ca2+, phosphate and lactate levels. Plasma SL levels returned to the initial level along with the recovery of blood acid-base status. In contrast, plasma cortisol levels stayed elevated even 24 h after exercise. There was no correlation between plasma PRL and GH levels and blood pH. Elevation of plasma SL levels during acidosis suggests the possible involvement of SL in acid-base regulation in rainbow trout.

Elevated dietary intake of L-tryptophan counteracts the stress-induced elevation of plasma cortisol in rainbow trout (Oncorhynchus mykiss)

2002 ◽  
Vol 205 (23) ◽  
pp. 3679-3687 ◽  
Author(s):  
Olivier Lepage ◽  
Olof Tottmar ◽  
Svante Winberg
Keyword(s):  
Rainbow Trout ◽  
Plasma Cortisol ◽  
Elevated Plasma ◽  
Monoamine Neurotransmitter ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Serotonergic Activity ◽  
Commercial Feed ◽  
Pelleted Feed ◽  
Cortisol Levels ◽  
Neuroendocrine Axis

SUMMARYJuvenile rainbow trout were isolated in individual compartments and allowed to acclimate for 1 week, during which they were fed commercial trout pellets. The feed was then replaced by pelleted feed supplemented with L-tryptophan(TRP) at two, four or eight times the concentration in the commercial feed. Fish were fed these supplemented feeds daily to satiety for 1 week, after which half of the fish were stressed, by lowering the water level for 2 h,while the remaining fish were left undisturbed. In undisturbed fish,supplementary dietary TRP resulted in slightly elevated plasma cortisol levels. In response to the stress, fish that had been fed control feed showed elevated plasma cortisol levels, but fish fed the TRP-supplemented feed displayed a significant reduction in this stress-induced elevation of plasma cortisol levels. Plasma and brain TRP levels were elevated in fish fed TRP-supplemented feed. TRP is the precursor of the monoamine neurotransmitter serotonin. Brain serotonergic activity was elevated by stress and also tended to be increased by elevated dietary TRP intake. The central serotonergic system is involved in the control of the hypothalamic—pituitary—interrenal axis, the action of serotonin being to stimulate or inhibit this neuroendocrine axis through different projections.

scholarly journals Stress elevates corticotropin-releasing factor (CRF) and CRF-binding protein mRNA levels in rainbow trout (Oncorhynchus mykiss)

2005 ◽  
Vol 186 (1) ◽  
pp. 123-130 ◽  
Author(s):  
C Doyon ◽  
V L Trudeau ◽  
T W Moon
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Plasma Cortisol ◽  
Preoptic Area ◽  
Binding Protein ◽  
Corticotropin Releasing Factor ◽  
Stress Axis ◽  
Control Group ◽  
Mrna Levels ◽  
Cortisol Levels

The objectives of this study were to characterize rainbow trout (Oncorhynchus mykiss) corticotropin-releasing factor (CRF)-binding protein (CRF-BP) cDNA and to examine the variations in CRF-BP and CRF mRNA levels in response to different intensities of stress. Trout were physically disturbed by a single or three consecutive periods of chasing until exhaustion followed by 2 h of recovery. The pituitary CRF-BP and preoptic area CRF1 mRNA contents were significantly increased only after repeated chasing events. Physical disturbance increased plasma cortisol levels with the largest change occurring in the group of trout that were exposed to repeated chasing events. Trout were also individually isolated in 120 l tanks or confined to 1.5 l boxes for 4, 24 or 72 h. CRF-BP mRNA levels in confined fish were greater than those of isolated fish at 72 h although there were no differences compared with the control group. CRF1 mRNA levels in the preoptic area were greater and remained elevated for a longer period in confined compared with isolated trout. Isolation led to a transient increase in plasma cortisol levels, but the higher cortisol values developed in the confined fish suggest that this treatment was more stressful than isolation. These results demonstrate that the intensity and duration of stress are important factors regulating CRF and CRF-BP mRNA levels in rainbow trout. We hypothesize that pituitary CRF-BP is involved in regulating the activity of the stress axis, possibly by reducing access to CRF1 receptors in the corticotropes.

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