Changes in oxytocin concentrations in saliva of pigs after a transport andduring lairage at slaughterhouse

Abstract

Oxytocin is associated with reproductive physiology but also with welfare and positive emotions. In this study,oxytocin was measured in saliva samples of 45 pigs that were collected before being transported to theslaughterhouse, at the time of arrival and 4 h after arrival to the slaughterhouse. Two previously validatedassays, one that measures free oxytocin and other that measures oxytocin linked to proteins, were used. Inaddition, cortisol, salivary alpha-amylase (sAA), total esterase activity (TEA), butyrylcholinesterase (BChE) andlactate dehydrogenase (LDH), which are biomarkers associated with stress and pain in pigs, were measured. Theresults showed a decrease in free and protein-linked oxytocin concentrations at 4 h after transport comparedwith the time before transport, while cortisol, sAA, TEA, BChE and LDH showed an increase at 4 h after transportcompared with the time before transport. Based on these results it can be concluded that the transport andlairage at slaughterhouse in the conditions of this study produce a decrease in oxytocin in the saliva of pigs thatcould indicate a reduced emotional well-being