Measurement of corticosterone in the plasma, eggs and faeces of laying hens

Abstract

Context Stress responses in chickens are commonly assessed from measurements of corticosterone in blood, but there is an increasing research effort to develop non-blood means of assessing the activity of the hypothalamo–pituitary (HPA) axis. It is common to measure corticosterone in the eggs and faeces. Aims We extended previous work by undertaking a study of caged laying hens comparing basal concentrations of corticosterone in plasma, faeces, egg albumen and egg yolk on a between-cage basis. We tested the hypothesis that there are positive relationships between corticosterone in plasma and corticosterone in each of the other matrices. Methods Blood samples were collected from each bird at a single point in time. In Experiment 1, these comparisons (between plasma concentrations of corticosterone on Day 1 and egg albumen, egg yolk and faecal concentrations of corticosterone on Days 1, 3 and 4 of the study) were made for hens of two ages under basal conditions, whereas, in Experiment 2, the comparisons (between plasma concentrations of corticosterone on Day 3 and egg albumen, egg yolk and faecal concentrations of corticosterone on Days 1 and 2 of the study) were made for hens housed at different space allowances with and without access to a nest box. The birds without a nest box had not had experience with a nest box prior to sampling. Key results There was a statistically significant (P = 0.012), but limited, positive relationship between plasma and egg albumen concentrations of corticosterone under basal conditions in Experiment 2. There were no other statistically significant (P > 0.05) relationships in either experiment. These results suggest that measures of corticosterone in the albumen, yolk and faeces of laying hens are unlikely to be robust predictors of basal concentrations of corticosterone in the blood. Conclusions Although there was some indication that concentrations of corticosterone in albumen may be related to concentrations in blood under basal conditions, based on all the results, this suggestion is made cautiously. Implications More comprehensive research is required to establish if measures of corticosterone in egg components and faeces are related to chronic basal activity of the hypothalamo–pituitary axis in laying hens. There is also a need to understand the impact of corticosterone on production, reproduction and welfare in hens from measures in both blood and non-blood matrices.

Effects of dietary protein levels on performance, nitrogen excretion, and odor emission of growing pullets and laying hens

“…Indeed, corticosterone was elevated in laying hens raised under suboptimal conditions including high stocking density, heat stress, or immune suppression ( Najafi et al, 2015 ; Nawab et al, 2020 ). Per the positive relationships between corticosterone concentration in eggs and blood samples ( Engel et al, 2022 ), our finding might indicate that laying hens fed on low CP diets were in a less stressed state. On the contrary, Lee et al (2016) reported that low CP diets (18 vs. 19% CP in diets) tended to increase serum concentration of corticosterone in broiler chickens.…”

Heat stress and poultry production: a comprehensive review

“…Hormones in egg can lead to changes in phenotype which influences physiology, behavior, and morphology ( Peixoto et al, 2020a ; Oluwagbenga et al, 2023a ). GC deposition in egg has been reported ( Love et al, 2008 ; Okuliarová et al, 2010 ; Caulfield and Padula, 2020 ; Engel et al, 2022 ; Oluwagbenga et al, 2023b ) and an increase in deposition has been reported following HS in laying hens ( Downing and Bryden, 2008 ; Kim et al, 2022a ), Japanese quails ( Pu et al, 2019 , 2020 ), and ducks ( Oluwagbenga et al, 2022 ).…”