Response of salivary haptoglobin and serum amyloid A to social isolation and short road transport stress in pigs

The possible use of serum amyloid A and haptoglobin (Hp) determination in saliva as stress markers in swine was investigated in this study. Firstly, a model of social isolation was followed. Significantly higher serum amyloid A concentrations were obtained in isolated animals (n = 10) compared to grouped animals (n = 10; P = 0.036), in agreement with cortisol levels (P = 0.015), while haptoglobin levels did not significantly change. Secondly, animals were subjected to short road transport. Cortisol and serum amyloid A levels significantly increased following road transport. Serum amyloid A levels were significantly high on arrival at the slaughterhouse and maximal at 30 and 60 min lairage (P < 0.0001). Cortisol levels were only significantly elevated on arrival at the slaughterhouse (P < 0.0001). These results indicate that salivary serum amyloid A (and not haptoglobin) determination is a potential biomarker for the assessment of complex stress in pigs, and that it has a more prolonged response than cortisol.