Changes in immunity- and stress- biomarkers in saliva following treatment of pigs with meningitis due to Streptococcus suis

The aim of this research was to evaluate the possible changes in a profile of biomarkers in saliva integrated by C-reactive protein (CRP), haptoglobin (Hp), adenosine deaminase (ADA), calprotectin (S100A8/A9), alpha-amylase (sAA) and total proteins (TP) in pigs with Streptococcus suis (S. suis) infection before and after treatment. Furthermore, a secondary aim was to provide data on the analytical validation of the two methods used in this report to quantify CRP and Hp in porcine saliva based on AlphaLISA technology. CRP and Hp assays were precise and accurate. When the response of pigs with S. suis infection to treatment was evaluated, significantly lower concentrations of salivary CRP and sAA were observed in the pigs that recovered from the disease and did not present signs of illness at 3 days post-treatment in comparison to the pre-treatment sampling (p < 0.05 and p < 0.01, respectively). At 7 days after treatment, all evaluated salivary biomarkers showed a decrease in the recovered group compared to non-recovered group after treatment. In conclusion, methods developed for CRP and Hp assays in this report showed adequate analytical validation results. Furthermore, saliva could be used for treatment monitoring of S. suis infection, being the effective response to the treatment associated with a decrease in the analytes measured in this report.