Evaluation of new biomarkers of stress in saliva of sheep

Abstract

Some routine handling procedures can produce stress in farm animals, and an adequate control of these stressors is important to avoid the negative effects on animal health and production. The measurement of biomarkers in saliva can be a suitable tool for the evaluation and control of stress. In this report, lipase, butyrylcholinesterase (BChE), total esterase (TEA) and adenosine deaminase (ADA) activities in the saliva of sheep were evaluated as biomarkers of stress. For this purpose, they were measured after inducing stress by facing a dog (experiment 1) and shearing (experiment 2), and comparing them to other stress salivary biomarkers such as α-amylase (sAA) and cortisol, as well as heart rate (HR). Each analyte was measured at the basal time, and during and just after the end of the stressful stimulus, and at various times for the first hour after the period of stress induction. Values were compared with those obtained from a control group. Lipase was the only analyte that showed significant changes between the stress and the control group in both experiments. Although TEA and ADA increased after stress, no significant differences were seen compared with the control group. Lipase was correlated highly with sAA and HR, in experiment 1; and correlated moderately with cortisol and HR in experiment 2. Lipase showed the greatest percentage increase after the stressful stimuli and less overlap with the control group in the two experiments. From the results of this study it can be concluded that lipase, TEA, BChE and ADA are enzymes present in the saliva of sheep and that they can be measured by using simple and fast colorimetric methods. Further studies should be undertaken with regard to the possible application of lipase as a biomarker of stress in sheep.

Characterization of total adenosine deaminase activity (ADA) and its isoenzymes in saliva and serum in health and inflammatory conditions to four different species: an analytical and clinical validation pilot study

“…In animals, increased tADA activity in saliva has been described in bitches with pyometra [32] and pigs with lameness [26], probably due to the presence of a systemic in ammatory process. Recently, tADA has been measured in saliva from sheep, cow, and horses [33,34,35].…”

Identification of possible new salivary biomarkers of stress in sheep using a high-resolution quantitative proteomic technique

“…Details describing sheep model, in which salivary biomarkers of stress were evaluated, was published in a recent paper (Contreras-Aguilar et al, 2018).…”

“…The animals were removed from the flock one at a time and the stress stimulus implemented, which consisted of being sheared with a shearing machine for approximately five minutes. The samples collected just after shearing were used in the proteomic study, and the samples were selected on the basis of significant increases of salivary biomarkers (cortisol, alpha-amylase and lipase) showed by Contreras et al (2018). Saliva samples were obtained using placing a sponge in the mouth.…”

“…When sponges were thoroughly moist, they were placed in plastic tubes (Salivette; Sarstedt, Aktiengesellschaft & Co., Nümbrecht, Germany), centrifuged (3,000 g for 10 min, 4°C), and the supernatant was aliquoted and kept at −80°C until analysis. The results of salivary biomarkers from freshly obtained saliva samples were reported in the previous study (Contreras-Aguilar et al, 2018). The aliquots of samples were stored, approximately for a year, at -80°C until proteomic analysis (Internal Disease Clinic, Faculty of Veterinary Medicine, University of Zagreb in Zagreb, Croazia).…”

“…Despite this lack of published research, in the last several years, there has been increasing interest in the measurement of saliva biomarkers to evaluate stress in sheep, and analytes such as cortisol, alpha-amylase, and lipase have been assayed to determine their increase in concentration after different stressful stimuli (Fuentes et al, 2016;Mesori et al, 2017;Contreras-Aguilar et al, 2018). The insight in various biological pathways in saliva induced by stress as well the identification of new proteins that can change in stressful situations can help researchers to gain knowledge about the status of salivary secretory proteome components and to identify new possible biomarkers that may be helpful to prevention of the stress situations.…”