Effects of maternal stress and cortisol exposure at the egg stage on learning, boldness and neophobia in brook trout

Behaviour ◽  
2016 ◽  
Vol 153 (13-14) ◽  
pp. 1639-1663 ◽  
Author(s):  
Sergio Cortez Ghio ◽  
Antoine Boudreau Leblanc ◽  
Céline Audet ◽  
Nadia Aubin-Horth

The environment experienced by females can have long-lasting effects on offspring phenotype. The objective of this study was to determine if maternal stress-induced behaviour reprogramming in offspring is found in brook char and to test whether cortisol is the main mediator, by separating the potential effects of cortisol from that of other potential maternal factors. We exposed female brook trout (Salvelinus fontinalis) to different parallel treatments during the oogenesis period: undisturbed as controls (1) fed cortisol through food (2) or physically stressed by handling once a week (3). Additionally, we exposed half of the control eggs to a cortisol suspension before fertilisation (4). Cortisol consumption and handling did not elevate either maternal plasma or egg cortisol, although egg cortisol level was significantly increased when eggs were bathed in the suspension. We measured spatial learning and memory, boldness and neophobia in 6 month-old offspring and found no effects of treatments on learning, memory or behaviour. Our results suggest that the relationship between maternal stress, circulating and egg cortisol levels, other maternal factors, and behavioural reprogramming is context and species-specific.

1993 ◽  
Vol 50 (8) ◽  
pp. 1717-1727 ◽  
Author(s):  
A. Hontela ◽  
J. B. Rasmussen ◽  
K. Lederis ◽  
H. V. Tra ◽  
G. Chevalier

The levels of arginine vasotocin (AVT), an osmoregulatory peptide, were determined by radioimmunoassay in brain tissue of brook trout (Salvelinus fontinalis) of a wide size range (50–380 mm) from softwater Laurentian lakes ranging in pH from 5.0 to 6.9 at different seasons. Multivariate models (ANCOVA) were developed to quantify the relationship between AVT, pH, body size, and season. Brain AVT levels increased with body size, and the allometric slope was highest in the low-pH lakes (pH 5.0-5.5). Although brook trout > 150 mm had higher brain AVT levels at low pH, no significant differences were detected for brook trout < 150 mm. We hypothesize that the sensitivity of brook trout at the parr stage to acid stress may be linked to their inability to mobilize a hormonal response involving AVT. The seasonal variation in brain AVT levels was similar in all the lakes studied, summer levels being the highest. Although this field study revealed that AVT levels depend also on factors other than acid stress (body size and season), our ANCOVA models allow adjustment for the effects of these covariables. Analyses of this type can be used to field test and calibrate biomarkers for use in ecotoxicology.


2016 ◽  
Vol 283 (1823) ◽  
pp. 20152601 ◽  
Author(s):  
Daniel E. Ruzzante ◽  
Gregory R. McCracken ◽  
Samantha Parmelee ◽  
Kristen Hill ◽  
Amelia Corrigan ◽  
...  

The relationship between the effective number of breeders ( N b ) and the generational effective size ( N e ) has rarely been examined empirically in species with overlapping generations and iteroparity. Based on a suite of 11 microsatellite markers, we examine the relationship between N b , N e and census population size ( N c ) in 14 brook trout ( Salvelinus fontinalis ) populations inhabiting 12 small streams in Nova Scotia and sampled at least twice between 2009 and 2015. Unbiased estimates of N b obtained with individuals of a single cohort, adjusted on the basis of age at first maturation ( α ) and adult lifespan (AL), were from 1.66 to 0.24 times the average estimates of N e obtained with random samples of individuals of mixed ages (i.e. ). In turn, these differences led to adjusted N e estimates that were from nearly five to 0.7 times the estimates derived from mixed-aged individuals. These differences translate into the same range of variation in the ratio of effective to census population size within populations. Adopting as the more precise and unbiased estimates, we found that these brook trout populations differ markedly in their effective to census population sizes (range approx. 0.3 to approx. 0.01). Using A ge N e , we then showed that the variance in reproductive success or reproductive skew varied among populations by a factor of 40, from V k / k ≈ 5 to 200. These results suggest wide differences in population dynamics, probably resulting from differences in productivity affecting the intensity of competition for access to mates or redds, and thus reproductive skew. Understanding the relationship between N e , N b and N c , and how these relate to population dynamics and fluctuations in population size, are important for the design of robust conservation strategies in small populations with overlapping generations and iteroparity.


1966 ◽  
Vol 44 (2) ◽  
pp. 173-190 ◽  
Author(s):  
Donal A. Hurley ◽  
Kenneth C. Fisher

A study of the external membranes of the developing oocyte of the brook trout, Salvelinus fontinalis, was made by means of electron microscopy. The membrane, zona radiata, which becomes "hardened" in mature eggs after they are shed into water, was observed to begin development at the bases of microvilli which project from the surface of the oocyte. This membrane grows until in the mature egg it is about 50 μ thick. The zona radiata is completely permeated by numerous pore canals. In immature oocytes, the pore canals contain microvilli which arise from the surface of the oocyte. The microvilli make contact with the follicular cells surrounding the developing oocyte. Morphological changes which occur in the zona radiata and the other layers of developing oocytes are described at several stages of development. The relationship between morphological changes in the membranes and the transport of nutrients to the developing oocyte is discussed.The nomenclature of the membranes of the mature trout egg is discussed in relation to the findings of the present study. It is concluded that primary membranes and perhaps secondary membranes are present in the mature trout egg.


2021 ◽  
Vol 2 ◽  
Author(s):  
Alina C. Stimmell ◽  
Zishen Xu ◽  
Shawn C. Moseley ◽  
Sarah D. Benthem ◽  
Diana M. Fernandez ◽  
...  

In early Alzheimer's disease (AD) spatial navigation is one of the first impairments to emerge; however, the precise cause of this impairment is unclear. Previously, we showed that, in a mouse model of tau and amyloid beta (Aβ) aggregation, getting lost represents, at least in part, a failure to use distal cues to get oriented in space and that impaired parietal-hippocampal network level plasticity during sleep may underlie this spatial disorientation. However, the relationship between tau and amyloid beta aggregation in this brain network and impaired spatial orientation has not been assessed. Therefore, we used several approaches, including canonical correlation analysis and independent components analysis tools, to examine the relationship between pathology profile across the parietal-hippocampal brain network and spatial reorientation learning and memory performance. We found that consistent with the exclusive impairment in 3xTg-AD 6-month female mice, only 6-month female mice had an ICA identified pattern of tau pathology across the parietal-hippocampal network that were positively correlated with behavior. Specifically, a higher density of pTau positive cells predicted worse spatial learning and memory. Surprisingly, despite a lack of impairment relative to controls, 3-month female, as well as 6- and 12- month male mice all had patterns of tau pathology across the parietal-hippocampal brain network that are predictive of spatial learning and memory performance. However, the direction of the effect was opposite, a negative correlation, meaning that a higher density of pTau positive cells predicted better performance. Finally, there were not significant group or region differences in M78 density at any of the ages examined and ICA analyses were not able to identify any patterns of 6E10 staining across brain regions that were significant predictors of behavioral performance. Thus, the pattern of pTau staining across the parietal-hippocampal network is a strong predictor of spatial learning and memory performance, even for mice with low levels of tau accumulation and intact spatial re-orientation learning and memory. This suggests that AD may cause spatial disorientation as a result of early tau accumulation in the parietal-hippocampal network.


2013 ◽  
Vol 70 (2) ◽  
pp. 280-293 ◽  
Author(s):  
Theodore Castro-Santos ◽  
Francisco Javier Sanz-Ronda ◽  
Jorge Ruiz-Legazpi

Sprinting behavior of free-ranging fish has long been thought to exceed that of captive fish. Here we present data from wild-caught brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta), volitionally entering and sprinting against high-velocity flows in an open-channel flume. Performance of the two species was nearly identical, with the species attaining absolute speeds > 25 body lengths·s−1. These speeds far exceed previously published observations for any salmonid species and contribute to the mounting evidence that commonly accepted estimates of swimming performance are low. Brook trout demonstrated two distinct modes in the relationship between swim speed and fatigue time, similar to the shift from prolonged to sprint mode described by other authors, but in this case occurring at speeds > 19 body lengths·s−1. This is the first demonstration of multiple modes of sprint swimming at such high swim speeds. Neither species optimized for distance maximization, however, indicating that physiological limits alone are poor predictors of swimming performance. By combining distributions of volitional swim speeds with endurance, we were able to account for >80% of the variation in distance traversed by both species.


1991 ◽  
Vol 48 (11) ◽  
pp. 2152-2162 ◽  
Author(s):  
Arunas P. Liskauskas ◽  
Moira M. Ferguson

The relationship between enzyme heterozygosity and several components of fitness (size and survival) was examined in a naturalized population of brook trout (Salvelinus fontinalis) from Algonquin Provincial Park, Ontario. Significant differences in allele frequency and the number of heterozygous loci per individual were found among five age classes spanning most of the life history stages of brook trout in this population. A young of the year (YOY) cohort sampled after a period of high natural mortality had significantly greater numbers of heterozygous loci per individual than YOY sampled shortly after emergence from redd sites. A positive association between heterozygosity and size was only found in YOY sampled in June and not in the other age classes in which sexual maturity was not a complicating factor. The association between heterozygosity and size was affected by the onset of sexual maturity. Significant negative regressions between multilocus or single locus heterozygosity and size were found in mature males whereas heterozygosity was positively associated with size in females. These dissimilarities may be the result of differences in growth rates prior to sexual maturation and differential allocation of energy towards gametic and somatic tissue.


1988 ◽  
Vol 45 (9) ◽  
pp. 1606-1613 ◽  
Author(s):  
D. G. McDonald ◽  
C. L. Millsgan

This study examined the effects of prolonged exposure [Formula: see text] to low Ca2+ (25 versus 400 μequiv/L), low pH (pH 5.2 versus 6.5) with and without Al (150 μg/L) on Na+ uptake in adult brook trout (Salvelinus fontinalis). Na+ uptake (JinNa+) was assessed by measuring radiotracer disappearance from the medium at ambient Na+ (79 μequiv/L) and in response to acute increases in ambient Na+. The relationship between JinNa+ and [Na+] was best described by a linear model with the slope of the line a measure of transport activity. Transport activity increased as a result of prolonged low Ca2+ exposure at pH 6.5, but declined in fish maintained at pH 5.2. These fish showed no compensation in response to low pH; there was no recovery in transport activity when pH was acutely raised to 6.5, and lower pH's further inhibited uptake. In contrast, the Na+ transport activity of fish maintained at pH 5.2 and 150 μg Al/L was significantly greater than that of fish acclimated to pH 5.2 alone and indeed greater than pH 6.5 controls. This indicates that Al exposure induced a compensatory mechanism in the gills that was not seen with low pH exposure alone.


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