Abstract:
Intensive pig management involves in a commercial setting the housing and implementation
of certain procedures, such as castration and tail docking, which may be stressful for the animal.
Good farming practices include the reduction of stress due to management processes,
but assessing the level of stress perceived entirely through behavioural observations can be
challenging. The monitoring stress-related physiological markers, like glucocorticoids (GC),
can be an accurate alternative that would presumably be more objective. In order to avoid
an additional stressor by taking blood, a non-invasive approach is advisable. We used an
adrenocorticotropic hormone (ACTH) stimulation test and the effect of transport to examine
the suitability of different enzyme immunoassays (EIAs) for monitoring adrenocortical function
in domestic pigs using saliva and faeces as sample matrices. An assay measuring faecal
glucocorticoid metabolites (fGCMs) with a 3ß,11ß-diol group has proven suited to
determine adrenocortical activity, showing an overall increase of 180% in fGCM concentrations
related to ACTH administration and of 70% related to transport, respectively. A cortisol
EIA was used to detect salivary glucocorticoid (sGC) concentrations, revealing a 1100%
increase in sGC concentrations after ACTH administration. The stability of fGCM concentrations
post-defecation was determined to assess possible changes in measured fGCM concentrations
in unpreserved faecal material over time, with fGCM concentrations being
relatively stable (maximal 12% change) under natural conditions for approximately two days
after defecation. This implicates that untreated faecal material from pigs can be analysed for up to two days after collection without appreciable level of depreciation in fGCM concentrations.
Being able to assess the physiological stress response of domestic pigs non-invasively
can help to improve the well-being of commercially reared pigs.
