Abstract
This work involves the development and validation of an enzyme immunoassay technique (EIA) for the measurement of the cortisol concentration in cattle saliva. Saliva samples present several advantages over plasma samples in animal welfare studies. Saliva collection avoids venipuncture as a stress factor. Also, saliva components do not affect EIA as plasma components do. At present, there is no validated commercial method for saliva cortisol determination in cattle. Commercially available radioimmunoassay kits for human plasma (detection range: 10-100 ng ml-1) are not sensitive enough for animals with low concentrations of salivary cortisol (< 4 ng ml-1). Thus, EIA is the method of choice in cattle. Sensitivity, specificity, precision and accuracy EIA tests showed this method to be suitable and reliable. The detection limit was found to be 0.024 ng ml-1, representing an improvement on previously described techniques. Intra-assay and inter-assay variation coefficients were 1.47-7.30% and 2.40-9.78%, respectively. The recovery rates for cortisol added to saliva samples were 91.36-126.5%. Parallelism tests showed that saliva cortisol levels can be determined in cattle samples without extraction. The correlation between saliva and plasma cortisol was positive (r = 0.75) and the saliva/plasma cortisol ratio was around 10%. Therefore, saliva samples are a suitable alternative to plasma samples in bovine HPA (hypothalamic-pituitary-adrenal) axis evaluation.
Highlights
Cortisol is a glucocorticoid hormone synthesized by the adrenal cortex
Cortisol concentrations rise in situations of stress and this parameter is considered to be an indicator of animal welfare (Cook et al, 1996; Ekkel et al, 1997)
Traditionally cortisol concentrations have been determined in plasma or serum, their determination in other fluids or organic tissues can be of interest in animal welfare studies of different species (Cooper et al, 1989; Fritsche and Steinhart, 1998; Verkerk et al, 1998; Cirimele et al, 1999; Fritsche et al, 1999; Antignac et al, 2000; Morrow, 2000; Palme et al, 2000)
Summary
Cortisol is a glucocorticoid hormone synthesized by the adrenal cortex. Its production, regulated by the corticotropic axis can be altered in different circumstances. Cortisol concentrations rise in situations of stress and this parameter is considered to be an indicator of animal welfare (Cook et al, 1996; Ekkel et al, 1997). Traditionally cortisol concentrations have been determined in plasma or serum, their determination in other fluids or organic tissues (saliva, milk, muscle, urine, faeces and hair) can be of interest in animal welfare studies of different species (Cooper et al, 1989; Fritsche and Steinhart, 1998; Verkerk et al, 1998; Cirimele et al, 1999; Fritsche et al, 1999; Antignac et al, 2000; Morrow, 2000; Palme et al, 2000). Salivary cortisol is a better indicator of the possible effects of the corticotropic axis on the animal organism than plasma cortisol. Blood extraction always produces stress in the animal that can cause cortisol levels to rise while the animals are hardly affected by saliva sample collection (Fell et al, 1985; Cooper et al, 1989)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
