Effect of genotype at a genetic marker for the GBP5 gene on resilience to a polymicrobial natural disease challenge in pigs

Authors: JEON, RL - Iowa State University; CHENG, J - Iowa State University; PUTZ, AM - Iowa State University; DONG, Q - Iowa State University; HARDING, JCS - University Of Saskatchewan; DYCK, MK - University Of Alberta; PLASTOW, GS - University Of Alberta; FORTIN, F - Quebec Pork Development Centre Inc; Lunney, Joan; ROWLAND, RRR - Kansas State University; DEKKERS, JCM - Iowa State University

Submitted to: Livestock Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/3/2021
Publication Date: 1/9/2021
Citation: Jeon, R., Cheng, J., Putz, A., Dong, Q., Harding, J., Dyck, M., Plastow, G., Fortin, F., Lunney, J.K., Rowland, R., Dekkers, J. 2021. Effect of genotype at a genetic marker for the GBP5 gene on resilience to a polymicrobial natural disease challenge in pigs. Livestock Science. 244:104399. https://doi.org/10.1016/j.livsci.2021.104399.
DOI: https://doi.org/10.1016/j.livsci.2021.104399

Interpretive Summary: Swine breeders have used a genetic marker [a single nucleotide polymorphism (SNP) for an allele of WUR0000125 (WUR)] to breed for resistance to porcine reproductive and respiratory syndrome (PRRS) virus infection. However, pigs face many more health issues. Breeders needed to determine whether this WUR marker selected for pigs with resilience to other disease challenges. This manuscript affirmed that selection for the WUR SNP is associated with resilience to a natural polymicrobial disease challenge. In fact, pigs with the favorable allele for the WUR SNP had significantly improved weight gain and health across the nursery and finisher stages. Thus, swine breeders can continue to use the WUR SNP as a marker for disease resilience to PRRS and polymicrobial diseases.

Technical Abstract: A genomic region on chromosome 4 that is tagged by single nucleotide polymorphism (SNP) WUR0000125 (WUR) was previously found to be associated with host response to porcine reproductive and respiratory syndrome (PRRS) virus infection. The objectives of this study were to 1) determine whether genotype at the WUR SNP is also associated with resilience to a natural polymicrobial disease challenge, 2) investigate the relationship of genotype at the WUR SNP with genotype at its putative causative mutation in the GBP5 gene, and 3) compare the association ofthe WUR and GBP5 SNPs with host response to PRRS virus (PRRSV) infection. Data from two studies were used: 1) Eight trials of the PRRS Host Genetic Consortium (PHGC), in which ~200 naïve crossbred nursery pigs/trial were infected with the NVSL-97-7895 strain of PRRSV to study the effects of genotype at the GBP5 and WUR SNPs on viral load and weight gain post-infection; 2) a natural disease challenge, where 3139 naïve crossbred nursery barrows were entered into a grow-finish facility that was seeded with multiple pathogens to maximize expression of disease resilience. Results from the PHGC trials showed that the WUR and GBP5 SNPs are in high but not complete linkage disequilibrium (r2=0.94). A haplotype analysis showed that discordant genotypes between the WUR and GBP5 SNPs were due to genetic recombination and not the result of genotyping errors. We were unable to determine whether GBP5 or WUR had a stronger effect on phenotype. Results from the natural disease challenge indicated that the favorable allele for the WUR SNP was significantly associated with greater average daily gain (p=0.02) and lower numbers of treatments in the challenge nursery (p=0.05) and across the nursery and finisher (p=0.01). Therefore, swine breeders can continue to use the WUR SNP not only as a marker for resilience to PRRSV infection, but also as a marker for disease resilience to a polymicrobial disease challenge.