A WUR SNP is associated with European Porcine Reproductive and Respiratory Virus Syndrome resistance and growth performance in pigs

Abstract

Porcine reproductive and respiratory syndrome (PRRS) causes decreased reproductive performance and respiratory problems in pigs. The goals of the current study were 1) to examine whether individual variation applies to infection with PRRSV European strains and 2) to investigate the association of a single nucleotide polymorphism (SNP) WUR10000125 (WUR) at the interferon-inducible guanylate-binding protein 1 gene (GBP1) with average daily gain (ADG) in PRRSV infected and uninfected pigs. The experimental procedure consisted of two trials in which pigs from negative PRRSV farms were infected with a wild-type (n=80) or vaccinated with an attenuated European PRRS virus strain (n=40) and then monitored after infection or vaccination. Viral load and ADG were determined for each pig. In a third trial, the ADG for PRRSV-free pigs was monitored. All pigs were genotyped for WUR at the GBP1 gene (AA and AG genotype were defined). Results indicated that there was individual variation in the viral load from pigs challenged with a wild-type or low virulent European PRRSV strain. Secondly, our data showed that WUR SNP was associated to ADG in vaccinated pigs. Thus, ADG in AG pigs was significantly higher than in AA ones after vaccinating with an attenuated PRRSV strain. However, the reverse happened in a PRRSV-free environment where the AA pigs were those that grew faster. Based on these results, there is a scope for selecting pigs according to their responses to PRRS virus infection with European strains and that WUR SNP may play a role in causing PRRSV resistance.

Host genetics of response to porcine reproductive and respiratory syndrome in nursery pigs

“…Genetic analyses of the first two trials by Dunkelberger et al (2017) demonstrated a low to moderate genetic basis for host response to PRRS vaccination (PRRS VL and WG) and to co-infection (PRRS and PCV2b VL and WG with or without prior vaccination), with heritabilities ranging from 0.07 to 0.57. Genotype at the WUR SNP had a significant association with host response, both post vaccination and post coinfection: post-vaccination, AB pigs had lower vaccine virus VL and faster gain than AA pigs, confirming results by Abella et al (2016) for vaccination with an attenuated European strain of the PRRSV. Post coinfection, AB pigs had lower PRRSV VL but did not significantly differ from AA pigs in growth rate.…”

“…The smaller effects of this major gene for the KS06 strain, in particular for WG, may reflect the lower pathogenicity of the KS06 strain, consistent with the lower VL and higher WG observed for that strain compared to the NVSL strain. Abella et al (2016) recently showed that genotype at WUR was also associated with growth rate following vaccination with an attenuated European strain of the PRRSV. However, when pigs were challenged with a wild-type European PRRSV strain, genotype at WUR was not significantly associated with VL, although pigs with the AB genotype had numerically lower VL (Abella et al, 2016).…”

“…Abella et al (2016) recently showed that genotype at WUR was also associated with growth rate following vaccination with an attenuated European strain of the PRRSV. However, when pigs were challenged with a wild-type European PRRSV strain, genotype at WUR was not significantly associated with VL, although pigs with the AB genotype had numerically lower VL (Abella et al, 2016). Both these studies were, however, based on small numbers (n = 40 and 80).…”

“…Abella et al (2016), however, also found pigs with the AB genotype at the WUR SNP to have lower growth rate during the grow-finish period in the absence of PRRS, which raises concerns about selecting pigs based on AB genotype at the WUR SNP. In work in progress, we have, however, not been able to replicate this finding in other commercial lines grown in clean environments and kept until market weight (Dunkelberger et al, 2017).…”

Modified-live PRRSV subtype 1 vaccine UNISTRAIN® PRRS provides a partial clinical and virological protection upon challenge with East European subtype 3 PRRSV strain Lena

“…Therefore, it is difficult to estimate the impact of slight genetic differences on the immunogenicity of the vaccine virus and the protection upon challenge (PRRSV strains DV and Lena have an identity of 88 % whereas VP-046 BIS and Lena have an 82.5 % identity (ORF5)). The different outcomes between both studies cannot be related to the genetic background in our opinion, as the piglets came from the same farm [30,31]. The major difference between both studies was the vaccination-challenge interval.…”