Gender influence on the salivary protein profile of finishing pigs

A study on gender differences in the normal range of biomarkers in porcine saliva samples has the scope for further attention. In the present study, the salivary protein profiles of age-matched healthy male and female finishing pigs were compared. The levels of salivary adenosine deaminase (ADA) activity, haptoglobin (Hp) and C-reactive protein (CRP) have been quantified in 32 male and 32 female pigs to ensure the presence of gender effect on the median levels of salivary biomarkers. Moreover, the total salivary protein content was quantified and compared. The overall salivary protein distribution was compared with SDS-PAGE in 14 male and 14 female pigs and the possible gender influence in the salivary protein profile was analysed by 2DE in 6 male and 6 female pigs. Statistically significant differences were observed in the median values of Hp, CRP, and ADA between male and female pigs (p < 0.005). Although the total salivary protein content was not different between the sexes, the salivary protein distribution and profile showed specific gender differences in three proteins of the lipocalin family: the odorant-binding protein, salivary lipocalin and lipocalin 1. These proteins have been related to animal immune status and should be further explored as possible porcine salivary biomarkers. Significance: The biological relevance of the reported research is based on the possible gender influence on the discovery of salivary biomarkers in porcine production. As differences have been reported in the salivary protein distribution in male pigs in comparison to that of female pigs, the normal-range values, according to gender, of the newly discovered biomarkers should be explored and defined prior to its application in the porcine production system. A hormonal sexual influence is highly hypothesized.