Cortisol Concentrations In Response Research Articles

Maternal childhood trauma and toddlers’ behavioural and endocrine reactions to a crying baby doll

BackgroundChildhood trauma can have long-term consequences for survivors, but also for survivors’ children. Children of childhood trauma survivors are more likely to develop aggressive and antisocial behaviour problems, indicating that parents’ childhood trauma may affect children’s social development. Less is known, however, about how maternal childhood trauma may affect positive aspects of children’s social behaviour, like their empathic and prosocial responses to witnessing others’ distress. Additionally, some studies suggest that maternal childhood trauma may also affect children’s physiology, particularly their endocrine responses to (dis)stress. We therefore examined the link between maternal childhood trauma experiences and children’s behavioural and endocrine responses to witnessing distress in others. MethodsWe recruited 75 mothers with 12-24 month-old toddlers. Mothers’ childhood trauma experiences was assessed and toddlers were exposed to a realistic-looking, crying baby doll, to assess their levels of distress, empathic concern for, and prosocial behaviour towards the doll. Saliva samples were taken two times prior to and one time 25minutes after exposing children to the crying doll, to assess toddlers’ baseline and reactivity cortisol concentrations in response to the crying doll. ResultsData analysis is still ongoing. The results contribute to understanding whether maternal childhood trauma can affect children’s behavioural and endocrine responses to others’ distress. ConclusionTo the best of our knowledge, this is the first study examining whether maternal childhood trauma can affect children’s responses – both behavioural and endocrine – to others’ distress. Our study may contribute to understand the intergenerational effects of childhood trauma on child social development.

291 Effect of Early vs. Late Maturing Sire Lines and Creep Feeding on the Stress Response, Intestinal Permeability, and Growth Performance of Nursery and Finishing Pigs

Abstract A total of 21 litters (early or late maturing Duroc × DNA 241) resulting in 247 pigs were used in a 170-day trial to determine the effect of sire lines selected for either early or late maturing growth rates and creep feeding on the stress response, intestinal permeability, and growth performance of nursery and finishing pigs. Treatments were arranged in a 2 x 2 factorial with main effect of Duroc sire line (early or late maturing) and creep feeding (with or without starting 14 d before weaning). In the nursery, there were 4 or 5 pigs per pen and 12 or 13 replications per treatment. Thirty minutes after weaning (initially 6.4 kg BW), 7 gilts per treatment were used to determine cortisol concentrations in response to weaning. Blood cortisol concentrations were increased (P < 0.01; 104.0 v. 83.5 ng/mL) in late maturing pigs compared with early maturing pigs. After almost no feed consumption by either group on d 1, late maturing pigs had decreased daily feed intake (P < 0.001) than early maturing pigs from days 2 to 14 post-weaning. Likewise, a greater percentage (P < 0.001) of late maturing pigs had BW less than their weaning weights on d 3 post-weaning compared with early maturing pigs (Table). Thus, late maturing pigs had decreased (P < 0.001) ADG and ADFI during the first 3 days in the nursery. Creep feeding had no effect on initial performance. No differences were observed in intestinal permeability between treatments. For overall nursery performance, a significant interaction was observed for ADG (P = 0.007) and ADFI (P < 0.001), with creep feeding providing a benefit in late maturing pigs, but not in early maturing pigs. Early maturing pigs had poorer G:F (P < 0.001) than late maturing pigs. At the end of the nursery, 241 pigs were transported to the finisher and randomly placed in pens based on treatment. There were 7 or 8 pigs per pen and 7 or 8 replications per treatment. For overall finishing performance, an interaction was observed for ADG (P = 0.037), with late maturing pigs that received creep feed having increased ADG compared with the other treatments. An interaction was also observed for ADFI (P = 0.007), with late maturing pigs that did not receive creep feed having decreased ADFI compared with late maturing pigs that received creep feed or early maturing pigs whether they received creep feed or not. In summary, early maturing pigs had lower stress response at weaning and improved ADG and ADFI until approximately 100 kg, at which point late maturing pigs began to exhibit greater ADG. Late maturing pigs had improved feed efficiency throughout the experiment. Creep feeding late maturing pigs resulted in improved growth performance compared with providing no creep feed, whereas creep feed did not impact early maturing pigs.

You're stressing me out! Effect of interspecific competition from red deer on roe deer physiological stress response

AbstractCortisol is the main glucocorticoid hormone commonly measured to assess adrenocortical activity in vertebrates in response to potential stressors. Competition and habitat quality may act as chronic stressors leading to an increase in cortisol accumulation. Moreover, chronic cortisol concentrations may seriously hamper the reproductive potential, health status and body condition of a species. Using hair collected from the rump of 88 adult roadkill roe deer Capreolus capreolus in the north‐eastern Italy, we aimed to assess the effect of both ungulate competitor population densities and habitat suitability on the long‐term physiological stress response of roe deer, using hair cortisol as a reference parameter. Our findings revealed that roe deer showed higher cortisol concentrations in response to higher red deer Cervus elaphus population density, most likely as a consequence of direct interspecific competition. No significant cortisol changes were however recorded in response to both wild boar Sus scrofa and roe deer population densities, probably as a result of reduced competition because of abundant feeding resources, different species population densities and spatial/temporal avoidance among species. Moreover, the absence of a significant effect as far as habitat suitability is concerned, suggest that roe deer are well adapted to live even in poor quality habitats most likely as long as they are close to better quality habitats which provide access to food resources and refuge sites. Our results highlight the importance of hair cortisol as a suitable parameter to assess physiological chronic stress response towards different environmental/ecological conditions.

Counterregulatory responses to postprandial hypoglycemia after Roux-en-Y gastric bypass.

Postbariatric hypoglycemia (PBH) is a potentially serious complication after Roux-en-Y gastric bypass (RYGB), and impaired counterregulatory hormone responses have been suggested to contribute to the condition. We evaluated counterregulatory responses during postprandial hypoglycemia in individuals with PBH who underwent RYGB. University hospital. Eleven women with documented PBH who had RYGB underwent a baseline liquid mixed meal test (MMT) followed by 5 MMTs preceded by treatment with (1) acarbose 50 mg, (2) sitagliptin 100 mg, (3) verapamil 120 mg, (4) liraglutide 1.2 mg, and (5) pasireotide 300 μg. Blood was collected at fixed time intervals. Plasma and serum were analyzed for glucose, insulin, glucagon, epinephrine, norepinephrine, pancreatic polypeptide (PP), and cortisol. During the baseline MMT, participants had nadir blood glucose concentrations of 3.3 ± .2mmol/L. At the time of nadir glucose, there was a small but significant increase in plasma glucagon. Plasma epinephrine concentrations were not increased at nadir glucose but were significantly elevated by the end of the MMT. There were no changes in norepinephrine, PP, and cortisol concentrations in response to hypoglycemia. After treatment with sitagliptin, 8 individuals had glucose nadirs <3.2 mmol/L (versus 4 individuals at baseline), and significant increases in glucagon, PP, and cortisol responses were observed. In response to postprandial hypoglycemia, individuals with PBH who underwent RYGB only had minor increases in counterregulatory hormones, while larger hormone responses occurred when glucose levels were lowered during treatment with sitagliptin. The glycemic threshold for counterregulatory activation could be altered in individuals with PBH, possibly explained by recurrent hypoglycemia.

Coping style and cortisol levels in infancy predict hair cortisol following new group formation in captive rhesus macaques (Macaca mulatta).

Social instability in primate groups has been used as a model to understand how social stress affects human populations. While it is well established that individual cercopithecines have different temperaments or personalities, little is known about how temperament mediates the experience of social instability in large, naturalistic groups. Here, we report findings from a study tracking a newly formed group of captive rhesus macaques (Macaca mulatta). We examine whether inter-individual differences in temperament during infancy affect physiological responses to new group formation years later, measured through hair cortisol 9 months after the group was formed. Our results show that early life measures of temperament characteristics predict later-life hypothalamic-pituitary-adrenal activity following new group formation, though not always in the directions we predicted. Individuals with higher blood cortisol concentrations in response to a novel stressor and lower blood cortisol concentrations following a Dexamethasone Suppression Test in infancy had lower hair cortisol values following new group formation later in life. Individuals characterized in infancy as more emotional or more active exhibited lower hair cortisol profiles 9 months after group formation. We suggest that these two temperament characteristics, emotionality and activity, may represent two different mechanisms leading to low hair cortisol values. That is, the physiological measure of low hair cortisol may have two different meanings depending on temperament characteristics of the individual. Our results demonstrate that temperament and physiological responsiveness measures in infancy can predict individual responses to a new group formation years later.

Low-dose ACTH stimulation testing in dogs suspected of hypoadrenocorticism.

BackgroundLow‐dose ACTH stimulation testing would lower cost and may increase sensitivity for identification of partial ACTH deficiency.Hypothesis(1) The low‐dose ACTH stimulation test will provide comparable results to the standard‐dose ACTH stimulation test in dogs suspected of hypoadrenocorticism and (2) partial ACTH deficiency exists in dogs and can result in chronic, intermittent gastrointestinal signs.AnimalsThirty‐one client‐owned dogs suspected of having hypoadrenocorticism.MethodsProspective study. Dogs suspected of having hypoadrenocorticism received 1 μg/kg cosyntropin IV for the first ACTH stimulation test; the second test was performed 4 h later and dogs received 5 μg/kg cosyntropin IV. Blood samples were obtained pre‐ACTH and 1 hour post‐ACTH for each dose (4 measurements total). Samples for endogenous ACTH measurement were obtained at the time of initial blood collection.ResultsNo significant difference was observed in the basal cortisol concentration before administration of a 1 μg/kg versus before a 5 μg/kg dose of cosyntropin (P = .544). For dogs suspected of having hypoadrenocorticism, the ACTH‐stimulated cortisol concentrations in response to both doses of ACTH were equivalent (90% confidence interval [CI], 80.5‐97.2%; P = .04). No cases with partial ACTH deficiency were identified conclusively.Conclusions and Clinical ImportanceA 1 μg/kg dose of cosyntropin is equivalent to a 5 μg/kg dose of cosyntropin for screening dogs suspected of hypoadrenocorticism. The existence of partial ACTH deficiency was not identified in this small group of dogs.

Hormonal and neuromuscular responses during a singles match in male professional tennis players

We sought to measure the response of cortisol concentrations around a professional tennis match and its association with hydration status and neuromuscular performance. Nine professional male tennis players were tested in a rest day, and 2-week after, during the first match of a professional tournament played in a clay-court. Salivary concentrations of cortisol (SalCC) were measured in a resting day (9:00 am and 8:00 pm), at the match day (9:00 am and 8:00 pm) and immediately before and after the match. Hydration status was assessed before the match (urine specific gravity; USG) while fluid turnover was tracked during the match. Finally, counter movement jump (CMJ) and handgrip isometric strength (HS) were measured before and after the match. SalCC, either in the morning (P = 0.161) and afternoon (P = 0.683) was similar in rest and match days. However, SalCC increased after the match (P = 0.033). Participants started the match hypohydrated (USG = 1.026±0.002) and during the match lost 1.0±0.3% of body weight despite 1.035±0.124 L/h of fluid ingested. CMJ and HS did not change post-match (P = 0.210 and P = 0.881, respectively). Correlations between the elevations in SalCC and dehydration (% BW loss) during the match were significant (r = -0.632; P = 0.034). Professional male tennis players did not show an anticipatory increase in SalCC the day of the match and neither signs of neuromuscular fatigue after it. During the match, the mild dehydration (i.e., <1.5%) was associated with the increases in cortisol levels which suggests that dehydration may be an added stress to be considered.

Effect of testosterone replacement on feeding behaviors after acute and chronic stress in gonadectomized male NMRI mice

We study the role of gonadectomy on the response to unavoidable stress and the role of testosterone replacement on gonadectomy in the male Naval Medical Research Institute mice (30±5 g) were studied. For this purpose, the hormonal and metabolic changes were investigated. In the experimental group, the gonads were surgically removed, and a cannula was inserted into the left lateral ventricle. For acute and chronic stress induction, animals were placed in the communication box for 30 min for one day and four consecutive days, respectively. The animals received different doses of intraventricular (ICV) testosterone (0.01, 0.05, 0.1 μg/mouse) 5 minutes or intraperitoneal (IP) testosterone (0.05, 0.01, 0.1 mg/kg) 30 minutes before the stress induction. The results showed that acute and chronic stress increases plasma cortisol concentration. IP testosterone injections of testosterone did not decrease cortisol concentrations in response to acute stress, whereas ICV injections did reduce cortisol concentrations. The stress reduced anorexia time, while the administration of testosterone increased anorexia time. In addition, acute stress reduced food intake in the gonadectomized mice. IP testosterone at 0.01 and 0.05 mg/kg increased food intake. Additionally, stress in gonadectomized mice reduced water intake, while the IP injection of testosterone in chronic stress further reduced water intake. Also, stress reduced the animals’ brain/adrenal volumes, while the IP and ICVinjection of testosterone at 0.01 mg/kg inhibited this effect. The results showed that the IP (0.05, 0.01, 0.1 mg/kg) and ICV (0.01, 0.05, 0.1 μg/mouse) administration of testosterone in the gonadectomized mice can modulate hormonal and metabolic changes induced by stress.

The effects of kennel size and exercise on the behaviour and stress physiology of individually-housed greyhounds

Greyhounds are routinely bred and managed for racing and are usually housed in individual kennels. To address the question of whether greyhounds would benefit from an increase in the minimum kennel size specified in the Victorian Code of Practice, the effects of kennel size and routine exercise on dog behaviour, stress physiology and injuries were examined. A total of 36 healthy greyhounds (aged 17 months (replicate 1 and 2) and 12 months (replicate 3)) were studied in three time replicates in a 2×2factorial experiment (kennel size of 3m2 and 10m2 of floor space, and two levels of exercise (‘no exercise’ and ‘exercise’(consisting of 2×10min per day and 3 times per week chasing a lure)) over 6 weeks. During the 1st and 5th week of treatment, dog behaviours were recorded for 2days in their kennels using time-lapse video. During the 6th week, six saliva samples were collected to measure basal cortisol concentrations, an ACTH challenge test was performed and injuries were assessed. Intensity of exercise had no significant (p≫>0.05) effect on behaviour, stress physiology and injuries. In the 1st week the adult dogs in large kennels spent more time in the front of the kennels (p≪0.05), less time in the back of the kennels (p≪0.01), less time lying (p≪0.05) and more time standing (p≪0.01) than those adult dogs in the small kennels. In week 5, the younger dogs in the large kennels spent more time at the front of the kennel (p≪0.05), less time in the back (p≪0.01) and spent more of their lying down time at the front and middle of the kennel (p≪0.001) than dogs in the small kennels. No significant differences in any of the measurements were found in the adult dogs in week 5. No abnormal or stereotypic behaviour was observed in Week 1 or 5. No significant differences in injuries, saliva cortisol concentrations and maximum cortisol concentrations in response to ACTH were found. The results of this study do not provide evidence that the smaller kennels and limited exercise increase the risks to dog welfare based on behaviour, stress physiology and injuries. Nevertheless, the observation that dogs tended to spend more time in the front of the large kennels where they were in view of other dogs could indicate that larger kennels may enable better welfare by providing additional social contact.

Milk cortisol response to group relocation in lactating cows.

The aim of the study reported in this Research Communication was to analyse the variations of milk cortisol concentrations in response to the relocation of dairy cows between production groups. Milk cortisol measured during 3 consecutive days did not vary significantly in cows without environmental perturbation. However, relocation of cows caused a significant increase of cortisol in milk starting from the first milking after the group change. This suggests that cortisol in milk can be a suitable biomarker to assess the HPA response of dairy cows to a short/medium-term environmental challenge.

Serum Cortisol Concentrations in Response to Ovario-hysterectomy and Following Post-operative Analgesia with Carprofen and Meloxicam in Dogs

Serum Cortisol Concentrations in Response to Ovario-hysterectomy and Following Post-operative Analgesia with Carprofen and Meloxicam in Dogs

Cortisol stress responses and children's behavioral functioning at school

The present study investigated whether cortisol stress responses of 6‐year‐olds were associated with their behavioral functioning at school. Additionally, the moderating role of stress in the family environment was examined. To this end, 149 healthy children (M age = 6.09 years; 70 girls) participated in an age‐appropriate innovative social evaluative stress test. Saliva cortisol samples were collected six times during the stress test to calculate two indices of the cortisol stress response: cortisol stress reactivity and total stress cortisol. Teachers assessed children's internalizing, externalizing, and prosocial behaviors. Stress in the family environment was operationalized as maternally reported parenting stress. Results indicated a significant increase in cortisol concentrations in response to the stressor. No significant associations were found between cortisol stress responses and behavioral functioning at school and there was no evidence for moderation by maternal parenting stress. Potential theoretical and methodological explanations for these results are discussed.

An assessment of immune and stress responsiveness in Holstein-Friesian cows selected for high and low feed conversion efficiency

The objective of this study was to assess the immune and stress responsiveness of cows identified as extremely high and low feed conversion efficiency phenotypes. The study utilised 16 Holstein-Friesian cows in their third to fourth lactation, and identified as having either extremely high (n = 8) or extremely low (n = 8) feed conversion efficiency. A commercial vaccine was used to induce measurable antibody- and cell-mediated adaptive immune responses and assess general immune responsiveness. Stress responsiveness was assessed by measuring changes in plasma cortisol concentrations in response to yarding and handling. No significant differences in antibody- or cell-mediated immune responsiveness were observed between the extreme high and low feed conversion efficiency phenotypes (P = 0.343 and 0.546, respectively). However, results suggested that plasma cortisol concentrations trended higher in the low feed conversion efficiency phenotype cows than their high feed conversion efficiency counterparts (P = 0.079) 48 h post-yarding and handling. A significant negative correlation was observed between antibody-mediated immune responsiveness and stress responsiveness (r = –0.44, P = 0.043) but not with cell-mediated immune responsiveness (r = 0.135, P = 0.309). This study provides preliminary evidence that cows selected for feed conversion efficiency may have improved stress-coping abilities and immune responsiveness.

Extending the recovery window: Effects of trait rumination on subsequent evening cortisol following a laboratory performance stressor

Mental rehearsal of past stressors through rumination may extend the physiological stress response and exposure to stress-related physiological mediators, such as cortisol. If repeated over time, this prolonged activation may contribute to a number of chronic health conditions. Findings from the emerging literature on the tendency to ruminate and its association with cortisol have been somewhat mixed. In the present study, we tested whether trait rumination predicted elevated cortisol concentrations in response to a performance stressor, and whether this association varied by the social-evaluative context of the stressor and gender. We also examined whether associations persisted into the evening of the stressor. Participants (50% female; mean age=19.83, SD=1.62) were randomly assigned to complete a laboratory speech stressor either in a social-evaluative (SET; n=86) or non-evaluative context (non-SET; n=58). Salivary cortisol concentrations were measured throughout the laboratory visit and later that evening. There was a main effect of trait rumination on greater total cortisol exposure into the evening of the stressor. In addition, trait rumination interacted with stressor context to predict cortisol declines: on the night of the SET stressor, high trait ruminators did not exhibit typical declines in cortisol. Different cortisol patterns emerged for men and women with tendencies to ruminate: women with higher rumination scores had flatter cortisol slopes with greater evening cortisol, whereas men with higher trait rumination scores had greater initial cortisol reactivity to the stressor. Together, these findings suggest that the relationship between the tendency to ruminate and cortisol concentrations is qualified by individual differences (gender) and stressor characteristics (social-evaluative threat).

Blunting of Exercise-Induced Salivary Testosterone in Elite-Level Triathletes With a 10-Day Training Camp

This study examined the influence of 10 days of intensified training on salivary cortisol and testosterone responses to 30-min, high-intensity cycling (55/80) in a group of male elite triathletes. Seven elite male triathletes (age 19 ± 1 y, VO2max 67.6 ± 4.5 mL · kg-1 · min-1) completed the study. Swim distances increased by 45%. Running and cycling training hours increased by 25% and 229%, respectively. REST-Q questionnaires assessed mood status before, during, and after the training period. Unstimulated saliva samples were collected before, after, and 30 min after a continuous, high-intensity exercise test. Salivary cortisol and testosterone concentrations were assessed. Compared with pretraining, blunted exercise-induced salivary testosterone responses to the posttraining 55/80 were found (P = .004). The absolute response of salivary testosterone concentrations to the 55/80 decreased pretraining to posttraining from 114% to 85%. No changes were found in exercise-induced salivary cortisol concentration responses to the 55/80. REST-Q scores indicated no changes in the participants' psychological stress-recovery levels over the training camp. The blunted exercise-induced salivary testosterone is likely due to decreased testicular testosterone production and/or secretion, possibly attributable to hypothalamic dysfunction or reduced testicular blood flow. REST-Q scores suggest that the triathletes coped well with training-load elevations, which could account for the finding of no change in the exercise-induced salivary cortisol concentration. Overall, these findings suggest that the 55/80 can detect altered exercise-induced salivary testosterone concentrations in an elite athletic population due to increased training stress. However, this alteration occurs independently of a perceived elevation of training stress.

Increased HPA axis response to psychosocial stress in remitted depression: the influence of coping style

The aim of the study was to examine the modulating effects of coping style on the response to psychosocial stress in remitted major depression (MD) and healthy controls. Thirty-three participants with a lifetime history of MD, who were in remission, and 32 age- and gender-matched healthy controls were recruited from a longitudinal-epidemiological study, in which the presence or absence of mental disorders was prospectively ascertained. Participants (aged 30–41 years) underwent two consecutive Trier Social Stress Tests (TSSTs). Subjects with a lifetime history of MD showed larger plasma ACTH and cortisol concentrations in response to both TSSTs, confirming a disturbed hypothalamic-pituitary-adrenal (HPA) axis regulation. Moreover, the MD group reported less positive, adaptive coping strategies and more negative, maladaptive strategies than the control group. The amount of negative coping predicted the size of the plasma cortisol response in the combined group. Our results demonstrate the importance of psychological coping strategies for the investigation of HPA axis response in depression.

Individual differences in foraging behavior and cortisol levels in recently emerged brook charr (Salvelinus fontinalis)

Recently emerged brook charr (Salvelinus fontinalis) foraging in still-water pools along the sides of streams tend to be either sedentary, feeding from the lower portion of the water column (a sit-and-wait tactic), or very active, feeding from the upper portion of the water column (an active search tactic). We tested whether the individual differences in foraging behavior were associated with baseline concentrations and responses of cortisol, a steroid hormone linked to personality differences in a variety of animals including fishes. We quantified the proportion of time spent on moving by focal charr in the field and then capturing them. Captured individuals were either (i) sacrificed immediately to quantify baseline cortisol concentrations, (ii) held in an unfamiliar field environment for 15 min and then sacrificed to quantify cortisol concentrations in response to handling and holding in a novel field environment, or (iii) held in an unfamiliar field environment with a white Plexiglas base (stressor) for 15 min to quantify cortisol concentrations in response to a novel object. Eleven statistical models relating cortisol concentrations to the proportion of time individuals spent on moving while searching for prey were compared using multi-model inferencing. Cortisol concentrations were higher for charr that spent a lower proportion of time on moving in the field than for charr that spent a higher proportion of time on moving. For a given proportion of time spent on moving, mean cortisol concentrations between baseline and experimental treatments, our measure of cortisol response, did not differ markedly. Our findings suggest that the foraging tactics displayed by wild brook charr in the field could reflect differences in how individuals perceive their environment.

Inoculation of dogs with a recombinant ACTH vaccine

To determine whether inoculation of healthy dogs with a recombinant peptide containing 3 copies of ACTH would result in the production of antibodies against ACTH and whether this would affect pituitary-adrenocortical function. 8 healthy dogs. A recombinant peptide consisting of 3 copies of ACTH fused to a T-helper cell epitope was produced in Escherichia coli. The protein was inoculated into 4 dogs at 4-week intervals (total of 3 inoculations/dog). Four control dogs received inoculations of PBS solution mixed with adjuvant. Blood samples were collected for determination of antibody titers against ACTH and for measurement of basal and ACTH-stimulated plasma cortisol concentrations. Inoculation with the ACTH vaccine resulted in production of anti-ACTH antibodies in all 4 dogs. Titers were initially high but declined by 15 weeks after the initial inoculation. Basal cortisol concentrations were unaffected by inoculation with the ACTH vaccine. Plasma cortisol concentrations in response to ACTH stimulation were reduced at 12 weeks, but not at 15 weeks, after the first inoculation. Inoculation of dogs with a recombinant ACTH vaccine resulted in the production of antibodies against the hormone. Anti-ACTH titers were initially high but were not sustained. The only detectable endocrine effect in treated dogs was a reduction in cortisol concentration in response to ACTH stimulation in 2 of 4 dogs at 12 weeks after the first inoculation. The effect of vaccine administration on the pituitary-adrenal system was subtle and transient.

Quantitative Trait Loci Affecting Response to Crowding Stress in an F2 Generation of Rainbow Trout Produced Through Phenotypic Selection

Selective breeding programs for salmonids typically aim to improve traits associated with growth and disease resistance. It has been established that stressors common to production environments can adversely affect these and other traits which are important to producers and consumers. Previously, we employed phenotypic selection to create families that exhibit high or low plasma cortisol concentrations in response to crowding stress. Subsequent crosses of high × low phenotypes founded a multigenerational breeding scheme with the aim of dissecting the genetic basis for variation underlying stress response through the identification of quantitative trait loci (QTL). Multiple methods of QTL analyses differing in their assumptions of homozygosity of the causal alleles in the grandparental generation yielded similar results in the F1 generation, and the analysis of two stress response phenotype measurement indexes were highly correlated. In the current study, we conducted a genome scan with microsatellites to detect QTL in the F2 generation of two families created through phenotypic selection and having larger numbers of offspring than families screened in the previous generation. Seven suggestive and three significant QTL were detected, seven of which were not previously detected in the National Center for Cool and Cold Water Aquaculture germplasm, bringing the total number of chromosomes containing significant and suggestive stress response QTL to 4 and 15, respectively. One significant QTL which peaks at 7 cM on chromosome Omy12 spans 12 cM and explains 25 % of the phenotypic variance in family 2008052 particularly warrants further investigation. Five QTL with significant parent-of-origin effects were detected in family 2008052, including two QTL on Omy12. The 95 % confidence intervals for the remaining QTL we detected were broad, requiring validation and fine mapping with other genotyping approaches and mapping strategies. These results will facilitate identification of potential casual alleles that can be employed in strategies aimed at better understanding the genetic and physiological basis of stress responses to crowding in rainbow trout aquaculture production.

Prenatal stress and ketamine affect the behavioral and physiological responsiveness of early adolescent pigs to a novel arena and social confrontation test

Elevated maternal glucocorticoid concentrations during gestation can affect how the offspring respond, both behaviorally and physiologically, to a challenge later in life. The objectives of this study were to first, determine if elevated maternal glucocorticoid concentrations during late gestation affect the behavioral and physiological response of the female offspring to a challenge during early adolescence, and secondly, determine if giving ketamine (an anxiolytic drug) effects these behavioral and physiological responses. During late gestation (d 76 until 115) sows were either repeatedly injected with ACTH (n=7) or control handled (n=7). Three female offspring from each sow were used in the study. A back test was performed on all experimental pigs during the first week of life. Pigs were tested in a novel arena (n=21/treatment) and social confrontation test (n=10/treatment) at 25 and 28 wk of age respectively, to assess anxiety-like behaviors. Two h prior to testing in the novel arena and social confrontation tests, pigs were given either ketamine (KET) or saline (SAL). The same pigs were then re-tested 7 d later and given the alternative drug treatment. Hypothalamic-pituitary adrenal function in response to an ACTH challenge and a social confrontation test was assessed. ACTH sows tended to have fewer (P=0.057) stillborn pigs than controls (0.4 and 0.0±0.14 pigs, respectively). In response to the novel arena test, ACTH pigs tended (P=0.056) to cross fewer squares than controls (77.2±6.71 and 93.5±93.5 squares, respectively), and pigs given ketamine spent less (P<0.05) time performing escape behaviors compared to pigs given saline (log-transformed, 0.0 and 0.3±0.11, respectively). In a social confrontation test, ACTH pigs spent more (P<0.05) time performing mounting behaviors than control pigs (log-transformed, 1.3 and 0.5±0.41, respectively). Furthermore, ACTH pigs given ketamine spent more (P<0.05) time nudging their pen-mate than ACTH pigs given saline (log-transformed, 3.9±0.29 and 2.9±0.27, respectively). Plasma cortisol concentrations in response to the social confrontation test were lower (P<0.05) in ACTH pigs given ketamine than ACTH pigs given saline (log-transformed, 1.9±0.37 and 2.7±0.23, respectively). These results suggest that exposure to elevated maternal glucocorticoids and ketamine can affect the behavioral and physiological reactivity of pigs in response to a challenge during early adolescence, and ketamine effects behavioral reactivity of control and prenatally stressed pig's differentially.