An initial genome-wide association study for haematological and blood clinical-biochemical parameters in Italian Duroc pigs

Blood-related traits, such as haematological and clinical-biochemical parameters, are key indicators of the physiological and health status of animals. These parameters can be considered intermediate phenotypes useful for dissecting more complex traits, such as resilience and disease resistance. In this study, we measured 15 haematological and 18 clinical-biochemical parameters in about 200 Italian Duroc pigs, using blood collected after slaughtering at the end of their production life, at 9 months of age. These pigs were also genotyped using the 60K single nucleotide polymorphism (SNP) panel. Blood parameters were first normalised using Box-Cox transformation, accounting for sex, weight and slaughtering date, as well as environmental and technical factors, which were then removed with a linear regression model. After SNP filtering and haplotype reconstruction, single-marker and haplotype genome-wide association studies were carried out. The single-marker analysis identified associations for 21 out of 33 blood traits. The most significant QTL was identified on porcine chromosome 3, associated with the level of LDL-cholesterol. This region contains the APOB gene known to affect this parameters in other pig breeds and other species. The results provide an initial genetic characterization of several blood parameters in Italian Duroc pigs. Further studies are needed to refine these results and evaluate if blood parameters can be used as proxies for other economically relevant traits. The research was supported by: (1) the Horizon Europe Re-Livestock project that has received funding from the European Union's Horizon Europe research and innovation programme under the grant agreement No. 101059609 (for the elaboration and analysis of the data); (2) the Italian PRIN2022 project FEEDTHEPIG, CUP J53D23018310001; (3) the Italian PRIN2022 HamCapture, CUP J53D23009570001; (4) the Agritech National Research Center (Agritech Spoke 1) and received funding from the European Union Next-GenerationEU (PIANO NAZIONALE DI RIPRESA E RESILIENZA (PNRR) – MISSIONE 4 COMPONENTE 2, INVESTIMENTO 1.4 – D.D. 1032 17/06/2022, CN00000022).