Department of Animal Science, Iowa State University, Ames, IA 50011, USA.
Department of Animal Science, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, 91540-000, Brazil.
J Anim Sci. 2021 May 1;99(5). doi: 10.1093/jas/skab097.
Antibody response, measured as sample-to-positive (S/P) ratio, to porcine reproductive and respiratory syndrome virus (PRRSV) following a PRRSV-outbreak (S/POutbreak) in a purebred nucleus and following a PRRSV-vaccination (S/PVx) in commercial crossbred herds have been proposed as genetic indicator traits for improved reproductive performance in PRRSV-infected purebred and PRRSV-vaccinated crossbred sows, respectively. In this study, we investigated the genetic relationships of S/POutbreak and S/PVx with performance at the commercial (vaccinated crossbred sows) and nucleus level (non-infected and PRRSV-infected purebred sows), respectively, and tested the effect of previously identified SNP for these indicator traits. Antibody response was measured on 541 Landrace sows ~54 d after the start of a PRRSV outbreak, and on 906 F1 (Landrace × Large White) gilts ~50 d after vaccination with a commercial PRRSV vaccine. Reproductive performance was recorded for 711 and 428 Landrace sows before and during the PRRSV outbreak, respectively, and for 811 vaccinated F1 animals. The estimate of the genetic correlation (rg) of S/POutbreak with S/PVx was 0.72 ± 0.18. The estimates of rg of S/POutbreak with reproductive performance in vaccinated crossbred sows were low to moderate, ranging from 0.05 ± 0.23 to 0.30 ± 0.20. The estimate of rg of S/PVx with reproductive performance in non-infected purebred sows was moderate and favorable with number born alive (0.50 ± 0.23) but low (0 ± 0.23 to -0.11 ± 0.23) with piglet mortality traits. The estimates of rg of S/PVx were moderate and negative (-0.38 ± 0.21) with number of mummies in PRRSV-infected purebred sows and low with other traits (-0.30 ± 0.18 to 0.05 ± 0.18). Several significant associations (P0 > 0.90) of previously reported SNP for S/P ratio (ASGA0032063 and H3GA0020505) were identified for S/P ratio and performance in non-infected purebred and PRRSV-exposed purebred and crossbred sows. Genomic regions harboring the major histocompatibility complex class II region significantly contributed to the genetic correlation of antibody response to PRRSV with most of the traits analyzed. These results indicate that selection for antibody response in purebred sows following a PRRSV outbreak in the nucleus and for antibody response to PRRSV vaccination measured in commercial crossbred sows are expected to increase litter size in purebred and commercial sows.
猪繁殖与呼吸综合征病毒（PRRSV）抗体反应（以样品与阳性的比值 S/P 表示）在纯种核心群的 PRRSV 爆发后和商业杂交母猪的 PRRSV 疫苗接种后（S/PVx），分别被提出作为 PRRSV 感染的纯种母猪繁殖性能提高的遗传指标特征，以及 PRRSV 疫苗接种的杂交母猪。在这项研究中，我们分别研究了 S/POutbreak 和 S/PVx 与商业（接种杂交母猪）和核心（未感染和 PRRSV 感染的纯种母猪）水平的性能之间的遗传关系，并测试了先前针对这些指标特征确定的 SNP 的影响。在 PRRSV 爆发开始后约 54 天，对 541 头长白母猪进行了抗体反应测量，并在接种商业 PRRSV 疫苗后约 50 天，对 906 头 F1（长白猪×大白猪）后备母猪进行了抗体反应测量。在 PRRSV 爆发之前和期间，分别对 711 头长白母猪和 428 头长白母猪进行了繁殖性能记录，并对 811 头接种 F1 动物进行了繁殖性能记录。S/POutbreak 与 S/PVx 的遗传相关系数（rg）的估计值为 0.72 ± 0.18。S/POutbreak 与接种杂交母猪繁殖性能的 rg 估计值为低至中度，范围从 0.05 ± 0.23 到 0.30 ± 0.20。S/PVx 与非感染的纯种母猪繁殖性能的 rg 估计值为适度且有利（活产仔数为 0.50 ± 0.23），但与仔猪死亡率性状相关的 rg 估计值较低（0 ± 0.23 至-0.11 ± 0.23）。S/PVx 的 rg 估计值在 PRRSV 感染的纯种母猪中为中度且为负（-0.38 ± 0.21），在其他性状中为低（-0.30 ± 0.18 至 0.05 ± 0.18）。先前报道的用于 S/P 比值的 SNP（ASGA0032063 和 H3GA0020505）的几个显著关联（P0 > 0.90）被鉴定为用于 S/P 比值和非感染的纯种母猪和 PRRSV 暴露的纯种母猪和杂交母猪的性能。包含主要组织相容性复合体 II 区域的基因组区域显著影响了对 PRRSV 抗体反应与大多数分析性状的遗传相关性。这些结果表明，在核心群的 PRRSV 爆发后，对纯种母猪的抗体反应进行选择，以及在商业杂交母猪中测量对 PRRSV 疫苗的抗体反应，预计会增加纯种和商业母猪的窝产仔数。
