Plasma corticosterone levels in laying hens from three different housing systems: preliminary results (original) (raw)
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Some opponents of cage housing for laying hens argue that nest boxes are important for hen welfare. Evidence to support this argument is that most hens choose to lay in a nest box if available (i.e. hens show preference), and hens are more active in the absence of a nest box and may perform pacing before egg laying (i.e. hens show frustration). In this experiment, in which hens were housed in groups of 2, 4 or 8 in 8-bird cages with and without a nest box, we investigated the relationship between pre-laying activity and basal stress levels, measured via corticosterone in eggs and plasma (~4-5 h post-laying). The posture and behaviour of 58 Hy-line Brown hens during 2-h pre-laying were collated from video records for a total of 135 egg-laying events. Hens that displayed more bouts of sitting posture, or that spent less time sitting, had higher plasma corticosterone concentrations. Further, hens that displayed more pre-laying activity had lower plasma corticosterone concentrations, although the occurrence of walk/run behaviour was not associated with plasma corticosterone. Lower activity, increased frequency of sitting and reduced time spent sitting prior to oviposition may reflect increased stress as indicated by the higher plasma corticosterone concentrations. While the evidence is limited, the finding that some pre-laying activities of hens were related to plasma corticosterone concentrations is contrary to expectation, and highlights a lack understanding of the relevance of pre-laying activity and sitting posture to layer hen welfare.
Physiology & Behavior, 2009
A corticosterone model was used to study the effects of chronic and repeated stress during the rearing phase on physiology, the onset of lay and performance of laying hens in the subsequent laying period. Two hundred and seventy Hy-line brown layer pullets were reared in environmentally controlled battery cages. At 7, 11, and 15 weeks of age birds were exposed for 1 week to the following treatments in drinking water: corticosterone dissolved in ethanol, ethanol, or untreated water. One week following each treatment, and at 35 weeks of age endocrine, metabolic and haematological tests were conducted. Body weight was measured throughout the study, and egg production was recorded daily throughout the laying period. Plasma corticosterone levels and heterophil to lymphocyte (H/L) ratio were increased after each corticosterone delivery, showing the effectiveness of the treatment. When corticosterone delivery was interrupted, plasma corticosterone and H/L ratio were significantly reduced. Exposing birds to repeated and long-term corticosterone treatment significantly affected BW (P b 0.01), and relative organ weights (P b 0.01). Corticosterone delivery also resulted in increased blood levels of glucose (GLU), cholesterol (CHOL), and triglyceride (TRG). Administration of corticosterone during the rearing phase delayed the onset of lay and decreased egg production at 35 weeks of age. These results demonstrate that oral corticosterone treatment affects hen physiology, reduces performance, and may model the effects of production stressors.
Poultry Science, 2020
Studies indicate that the evaluation of animal welfare in birds may be carried out with the measurement of the stress-related hormone corticosterone in feathers. However a standardized procedure for corticosterone measurements in feathers is lacking, a validation needs to be carried out for each new species before implementation. The aim of the present study was to establish a valid method to measure corticosterone concentrations in feathers of laying hens in a precise and repeatable manner using an established and commercially available ELISA. Validation was performed with feather pools of tail and interscapular feathers of commercial Lohmann Brown laying hens. Assessment groups, consisting of 5 replicates, were created. All replicates of an assessment group were processed at the same time. Each replicate was run in 4 repetitions by ELISA. Intra-assay and interassay CV was 7.5 and 6.4%, respectively. The serial dilution showed linearity and parallelism. Examining the hormone extraction efficiency by using different methanol volumes resulted in no statistical differences (P. 0.05). Pulverized feathers showed higher corticosterone values than minced feathers (P. 0.05). Differences were shown between 2 feather types (tail vs. interscapular feathers; P , 0.05), as well as between vane and rachis (P , 0.05). Performance of a freeze-thaw cycle led to a decrease of corticosterone concentrations in the samples. A possible effect of UV-A radiation on the stability of corticosterone in the feathers was not found (P. 0.05). With the present study, a valid protocol, feasible for analyzing feather pools of laying hens, was developed. It may provide fundamentals for further investigations on corticosterone in feathers as a noninvasive indicator to evaluate aspects of animal welfare.
Poultry Science, 2009
Measurements of the heterophil:lymphocyte (H/L) ratio (invasive technique) and corticosterone in yolk and albumen (noninvasive techniques) were used to measure stress in 3 commercial laying strains, Lohmann White (LW), H&N White (HN), Lohmann Brown (LB), and a noncommercial cross (CR) between Rhode Island Red (male) and Barred Plymouth Rock (female), kept in conventional cages or floor pens. All chicks were reared in their respective environments, and 450 and 432 pullets were placed at 18 and 7 wk of age in cages and floor pens, respectively. Blood from 12 hens per strain was taken at 19, 35, and 45 wk of age in each housing system. A total of 100 heterophils and lymphocytes were counted and their ratio (H/L ratio) was calculated. Corticosterone was measured in yolk and albumen from 12 hens per strain in each housing system at 22 and 45 wk of age. The H/L ratio was within the normal range. The interaction between en-vironment and strain for the H/L ratio showed that in both environments, LB and CR hens had a higher H/L ratio than LW and HN layers. In cages, there were significant differences in H/L ratios between LW and HN hens that were likely due to genetic differences. The LW hens had significantly lower corticosterone concentrations in yolk than LB hens. In cages but not floor pens, yolk corticosterone concentrations at wk 22 were significantly higher than at wk 45. In floor pens but not cages, albumen corticosterone at wk 22 was higher than at wk 45. The H/L ratios suggest that none of the hens were unduly stressed, and corticosterone levels in yolk and albumen support the suggestion that hens adapted to their environments with age. Although measurement of yolk corticosterone and the H/L ratio may be comparable, the measurement of corticosterone level in the albumen may differ because it is secreted over a short time.
Poultry Science, 2019
There is limited information on the effects of stress and/or physiological manipulation on plasma concentrations of corticosterone (CORT) in turkeys. Under basal conditions, there was evidence for episodic release of CORT in turkeys. The present studies determine the effects of handling, herding, herding, the administration of Escherichia coli endotoxin, and challenge with turkey adrenocorticotropic hormone (ACTH) on plasma concentrations of CORT in market-weight male turkeys. Plasma concentrations of CORT were increased after challenge with turkey ACTH, handling together with saline injection or herding (moving birds from one pen to another). There were no effects on plasma concentrations of CORT of the following putative stressors: handling per se, endotoxin challenge, or of placing in an inverted position on simulated shackles.
British Poultry Science, 2009
1. Previous studies have shown that more yolk corticosterone is found in the eggs of random bred Japanese quail hens implanted with corticosterone during egg formation; both unstressed and stressed quail hens selected for exaggerated (high stress) rather than reduced (low stress) plasma corticosterone response to brief restraint deposit more corticosterone into their egg yolks. The length of egg incubation is also known to be shorter in eggs laid by high than low stress hens. 2. Here we investigated the interactive effects of quail stress line (low vs. high stress) with maternal corticosterone treatment (empty implant controls vs. corticosterone-implants) during egg formation on length of egg incubation. 3. Mean (AESEM) length of egg incubation for high stress control eggs (397Á3 AE 0Á4 h) was similarly shorter (by about 4.5 h) than that found for low stress control eggs (392Á8 AE 0Á2 h). In addition, on average, the incubation length of eggs laid by corticosterone-implanted hens (392Á9 AE 0Á5 h) was nearly 3 h shorter than that found for eggs laid by control hens (395Á8 AE 0Á2 h) regardless of stress line. 4. Line  hen-implant treatment effects on mean (AESEM) length of egg incubation partitioned in rank order as follows: low stress control (397Á8 AE 0Á5 h)4low stress corticosterone-implant (395Á9 AE 0Á7 h)4high stress control (393Á8 AE 0Á3 h)4high stress corticosterone-implant (391Á2 AE 0Á4 h). 5. Our original contention that selection for exaggerated adrenocortical responsiveness is associated with a reduction in the length of egg incubation was supported. Because maternal stress-induced elevations of yolk B are known to occur, the present findings of further shortenings of the hatching times of eggs of corticosterone-treated hens of both stress lines are also important to the poultry industry because they warn producers that unless stress in hens during egg formation is minimised, abbreviated egg incubation periods may result beyond the effects that a hen's genetic predisposition to adrenocortical stress responsiveness has on the length of egg incubation.
Physiology & Behavior, 2009
The aim of the present study was to investigate the effect of brooding and group selection for low mortality on post-stress corticosterone and peripheral serotonin in laying hens. Birds in the experiment originated from the same population and were either group-selected for low mortality (low mortality line) or randomly selected (control line) for two generations. Twelve groups of seven birds from each line were used. Within each line, six groups were brooded by a foster mother and six groups were non-brooded. At 33 weeks of age, birds (n = 42/treatment) were manually restrained for 5 min, during which their behavioral response (number of struggles) was studied. Fifteen minutes after the start of the manual restraint, blood samples were drawn for assessment of plasma corticosterone and whole blood serotonin (5-HT) concentration. In the low mortality line, 80% of the birds struggled and vocalized vs. 72% in the control line (non significant). Birds from the control line had a higher plasma corticosterone concentration after manual restraint than birds from the low mortality line (7.7 vs. 6.0 nmol ml − 1 ). Furthermore, birds from the control line that were reared without a mother had a lower whole-blood 5-HT concentration than birds from the other treatments (45 vs. 48 nmol ml − 1 ). These results indicate that both brooding and selection for low mortality affect poststress corticosterone and peripheral serotonin concentration, which may result in a reduced propensity to develop feather pecking.
Impaired development of broiler chickens by stress mimicked by corticosterone exposure
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2006
The effects of corticosterone (CORT) administration on the development of muscular tissues of broiler chickens (Gallus gallus domesticus) fed with diets differing in lipid content were investigated. The experimental chickens were given one of two experimental diets: high lipid diet (9.9% crude fat) or control diet, from 21 d of age. At 28 d of age, half of the chickens in each dietary treatment were exposed to CORT treatment, supplemented with 30 mg CORT/kg diet for 12 days, while the other half continued to consume the former diet. The zootechnical parameters were recorded at 21, 28, 35 and 39 d, and a blood sample was obtained from 8 birds of each group, respectively. The growth performance of broiler chickens was significantly depressed by CORT administration, but not by dietary treatment. Corticosterone treatment resulted in enhanced energy expenditure. The results indicate that the development of breast muscle was more susceptible to stress mimicked by CORT administration. The results suggest that corticosterone administration enhanced hepatic fatty acid synthesis and resulted in the redistribution of energy to abdominal store from peripheral tissues. Diet rich in lipid content was favorable to the central fat deposit in stressed broiler chickens.