Study of the genetics of the porcine acute phase proteins

The principle aims of the work presented in this thesis were to further investigate the porcine acute phase proteins (APP) and determine the factors influencing the baseline concentrations of haptoglobin (Hp), C-reactive protein (CRP), Pig major acute phase protein (Pig-MAP) and transthyretin (TTR). The APP are used as markers of inflammation and sub-clinical disease and are considered potential biomarkers for pig health and welfare. They have also been identified as a possible means of breeding for disease resistance, however little is known about the genetics of the porcine APP. This study investigated associations between the APP genes and baseline concentrations and the heritability of those concentrations. An enzyme linked immunosorbent assay (ELISA) was developed for the measurement of porcine CRP, in-house methods were used for the determination of Hp and TTR and a commercial assay was used in the measurement of Pig-MAP. A population of pure line high health boars (n=~345) from 7 lines was used in the initial study each of which had an archived DNA sample and serum samples available for use. Baseline herd concentrations of the 4 APP were determined and correlations between Hp and CRP, Hp and Pig-Map and CRP and Pig-MAP were identified. Significant differences were found between the 7 breeding lines in CRP, Pig-MAP and TTR concentrations, indicating that selective breeding for performance traits may also have affected innate immune traits such as APP concentrations. Single nucleotide polymoiphisms (SNP) were identified in the 4 APP genes and 17 were genotyped across the boar population with line differences apparent in their allele frequencies for CRP, Pig-MAP and TTR. Statistical analysis showed that there were significant associations between 3 of the SNP located in the Hp gene and Hp baseline concentrations (p