SALIVARY IGA AS A MARKER OF SOCIAL STRESS IN RATS

Secretory immunoglobulin A (sIgA) has been suggested to be a potential marker of stress in the human and the dog. We describe a simple metho d of saliva collection from rats for quantification of salivary sIgA i n the first study of sIgA as a possible stress marker in the rat. Thre e groups of adult male rats were housed under different conditions (si ngly housed, paired with a female, and group housed). The animals were conditioned for the saliva collection by presenting a chocolate rewar d after every session and saliva was collected by soaking filter paper discs (5 mm in diameter) with saliva directly in the rats' oral cavit y. The levels of salivary sIgA were determined by a novel paper disc r ocket immunoelectrophoresis using sheep anti rat IgA antiserum. The re sulting rockets had similar morphology as rockets in a standard rocket immunoelectrophoresis. Males housed singly showed stable sIgA levels with little variation while those housed singly with a female showed a n initial decrease in sIgA followed by a steady increase. Males housed in a group (n = 6) showed a steady decline in sIgA levels. This indic ates that sIgA levels are reduced by social stress and that this molec ule may be a useful marker for well-being in the rat.