Research

Traits associated with innate and adaptive immunity in pigs: heritability and associations with performance under different health status conditions

Mary Clapperton¹ , Abigail B Diack² , Oswald Matika¹ , Elizabeth J Glass¹ , Christy D Gladney³ , Martha A Mellencamp⁴ , Annabelle Hoste⁵ and Stephen C Bishop¹

¹  The Roslin Institute and Royal Dick School of Veterinary Studies, University of Edinburgh, Roslin, Midlothian, EH25 9PS, UK

²  Faculty of Veterinary Medicine, University of Glasgow, G61 IQH, UK

³  Genus, De Forest, WI 53532, USA

⁴  Ralco Nutrition, Inc., 1600 Hahn Road, Marshall, MN 56258, USA

⁵  JSR Genetics Ltd, Driffield, East Yorkshire, Y025 9ED, UK

author email corresponding author email

Genetics Selection Evolution 2009, 41:54doi:10.1186/1297-9686-41-54

Published:	30 December 2009

Abstract

There is a need for genetic markers or biomarkers that can predict resistance towards a wide range of infectious diseases, especially within a health environment typical of commercial farms. Such markers also need to be heritable under these conditions and ideally correlate with commercial performance traits. In this study, we estimated the heritabilities of a wide range of immune traits, as potential biomarkers, and measured their relationship with performance within both specific pathogen-free (SPF) and non-SPF environments. Immune traits were measured in 674 SPF pigs and 606 non-SPF pigs, which were subsets of the populations for which we had performance measurements (average daily gain), viz. 1549 SPF pigs and 1093 non-SPF pigs. Immune traits measured included total and differential white blood cell counts, peripheral blood mononuclear leucocyte (PBML) subsets (CD4⁺ cells, total CD8α⁺ cells, classical CD8αβ⁺ cells, CD11R1⁺ cells (CD8α⁺ and CD8α^-), B cells, monocytes and CD16⁺ cells) and acute phase proteins (alpha-₁ acid glycoprotein (AGP), haptoglobin, C-reactive protein (CRP) and transthyretin). Nearly all traits tested were heritable regardless of health status, although the heritability estimate for average daily gain was lower under non-SPF conditions. There were also negative genetic correlations between performance and the following immune traits: CD11R1⁺ cells, monocytes and the acute phase protein AGP. The strength of the association between performance and AGP was not affected by health status. However, negative genetic correlations were only apparent between performance and monocytes under SPF conditions and between performance and CD11R1⁺ cells under non-SPF conditions. Although we cannot infer causality in these relationships, these results suggest a role for using some immune traits, particularly CD11R1⁺ cells or AGP concentrations, as predictors of pig performance under the lower health status conditions associated with commercial farms.