Genomic Regions Associated with Host Response to Porcine Reproductive and Respiratory Syndrome Vaccination and Co-Infection in Nursery Pigs

November 15, 2017 — 

The WUR1000125 (WUR) single nucleotide polymorphism (SNP) can be used as a genetic marker for host response to porcine reproductive and respiratory syndrome (PRRS), PRRS vaccination, and co-infection with porcine circovirus type 2b (PCV2b). Objectives of this study were to identify genomic regions other than WUR associated with host response to PRRS vaccination and PRRSV/PCV2b co-infection and regions with a different effect on host response to co-infection, depending on previous vaccination for PRRS.

METHODS:
Commercial crossbred nursery pigs were pre-selected for WUR genotype (n = 171 AA and 198 AB pigs) where B is the dominant and favorable allele. Half of the pigs were vaccinated for PRRS and 4 weeks later, all pigs were co-infected with PRRS virus and PCV2b. Average daily gain (ADG) and viral load (VL) were quantified post vaccination (Post Vx) and post co-infection (Post Co-X). Single-SNP genome-wide association analyses were then conducted to identify genomic regions associated with response to vaccination and co-infection.

RESULTS:
Multiple SNPs near the major histocompatibility complex were significantly associated with PCV2b VL (-log 10 P ≥ 5.5), regardless of prior vaccination for PRRS. Several SNPs were also significantly associated with ADG Post Vx and Post Co-X. SNPs with a different effect on ADG, depending on prior vaccination for PRRS, were identified Post Vx (-log 10 P = 5.6) and Post Co-X (-log 10 P = 5.5). No SNPs were significantly associated with vaccination VL (-log10 P ≤ 4.7) or PRRS VL (-log10 P ≤ 4.3). Genes near SNPs associated with vaccination VL, PRRS VL, and PCV2b VL were enriched (P ≤ 0.01) for immune-related pathways and genes near SNPs associated with ADG were enriched for metabolism pathways (P ≤ 0.04). SNPs associated with vaccination VL, PRRS VL, and PCV2b VL showed overrepresentation of health QTL identified in previous studies and SNPs associated with ADG Post Vx of Non-Vx pigs showed overrepresentation of growth QTL.

CONCLUSIONS:
Multiple genomic regions were associated with PCV2b VL and ADG Post Vx and Post Co-X. Different SNPs were associated with ADG, depending on previous vaccination for PRRS. Results of functional annotation analyses and novel approaches of using previously-reported QTL support the identified regions.

Dunkelberger JR, Serão NVL, Weng Z, Waide EH, Niederwerder MC, Kerrigan MA, Lunney JK, Rowland RRR, Dekkers JCM; Genomic Regions Associated with Host Response to Porcine Reproductive and Respiratory Syndrome Vaccination and Co-Infection in Nursery Pigs; BMC Genomics. 2017 Nov 13;18(1):865. doi: 10.1186/s12864-017-4182-8.

Read the complete article here: 10.1186/s12864-017-4182-8