APC Europe, S.L.U., Granollers, Spain; IRTA, Centre de Recerca en Sanitat Animal (CRESA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
APC Europe, S.L.U., Granollers, Spain.
Vet Microbiol. 2019 Dec;239:108450. doi: 10.1016/j.vetmic.2019.108450. Epub 2019 Oct 12.
Liquid porcine plasma is an animal origin raw material for the manufacturing process of spray-dried porcine plasma that is used in pig nutrition worldwide. In previous studies we found that the application of ultraviolet light C (UV-C) in liquid plasma that was inoculated with a variety of bacteria or viruses of importance in the swine industry can be considered as redundant safety steps because in general achieve around 4 logs reduction for most of these pathogens. However, the final validation of the UV-C light as safety feature should be conducted with commercial liquid plasma and using the pig bioassay model. As a first objective, the potential infectivity of a raw liquid plasma product collected from an abattoir was tested by means of a swine bioassay. We used Porcine circovirus 2 (PCV-2), a ubiquitous virus that has been systematically detected by PCR in porcine plasma at abattoirs as selection criteria for commercial liquid plasma lot. As a second aim of the study, the effects of different doses of UV-C irradiation on the selected raw liquid plasma were assayed in the animal bioassay. Moreover, other swine infecting agents, including Porcine reproductive and respiratory syndrome virus (PRRSV), were also determined in the original plasma and monitored in the inoculated animals. Pigs negative for PCV-2 and PRRSV genome and antibodies were allotted to one of five groups (6 to 8 pigs/ group) and injected intra-peritoneally with 10 mL of their assigned inoculum at 50 d of age. Negative control pigs (group 1) were injected with PBS. Positive control pigs (group 5) were injected with a PCV-2 inoculum. Groups 2, 3 and 4 were injected with liquid porcine plasma that had been subjected to 0 (raw plasma), 3000 or 9000 J/L UV-C irradiation, respectively. Group 2 pigs (0 J/L UV-C) got infection by PRRSV but no PCV-2 infection or seroconversion. However, one pig from group 2 seroconverted to Rotavirus A (RVA) and Hepatitis E virus (HEV) and three group 2 pigs seroconverted to Porcine parvovirus (PPV). Groups 1, 3 and 4 pigs showed no evidence of infection or seroconversion associated with the tested viruses or any other pathogens found in the liquid plasma before UV-C irradiation. Group 5 pigs developed PCV-2 infectivity as expected. UV-C irradiation of liquid plasma at 3000 and 9000 J/L was effective in preventing PRRSV and other pathogens transmission. Moreover, raw liquid plasma was non-infectious for PCV-2 in naïve pigs.
液态猪血浆是一种动物源性原料，用于制造喷雾干燥猪血浆，这种血浆在全球范围内用于猪的营养。在以前的研究中，我们发现，用紫外线 C（UV-C）处理接种了猪业中重要的各种细菌或病毒的液态血浆，可以被认为是多余的安全步骤，因为通常对于大多数这些病原体来说，UV-C 处理可实现约 4 个对数级的减少。然而，紫外线 C 光作为安全特性的最终验证应该使用商业液态血浆，并使用猪生物测定模型进行。作为第一个目标，我们使用猪圆环病毒 2（PCV-2）作为选择商业液态血浆批次的标准，通过猪生物测定来测试从屠宰场收集的原始液态血浆产品的潜在传染性。该病毒是一种普遍存在的病毒，在屠宰场的猪血浆中已通过 PCR 系统检测到。作为研究的第二个目标，我们在动物生物测定中检测了不同剂量的 UV-C 照射对所选原始液态血浆的影响。此外，还在原始血浆中确定了其他感染猪的病原体，包括猪繁殖与呼吸综合征病毒（PRRSV），并在接种的动物中进行了监测。将未感染 PCV-2 和 PRRSV 基因组和抗体的猪分配到五个组之一（每组 6 至 8 头猪），并在 50 日龄时通过腹膜内注射 10 mL 分配的接种物。阴性对照猪（第 1 组）注射 PBS。阳性对照猪（第 5 组）注射 PCV-2 接种物。第 2、3 和 4 组分别注射未经 UV-C 照射的液态猪血浆（原始血浆）、3000 或 9000 J/L UV-C 照射的液态猪血浆。第 2 组猪（0 J/L UV-C）感染了 PRRSV，但未感染 PCV-2 或发生血清转化。然而，第 2 组的一头猪血清转化为轮状病毒 A（RVA）和戊型肝炎病毒（HEV），三组 2 头猪血清转化为细小病毒（PPV）。第 1、3 和 4 组猪未显示出与测试病毒或在 UV-C 照射之前在液态血浆中发现的任何其他病原体相关的感染或血清转化证据。第 5 组猪如预期那样产生了 PCV-2 感染性。3000 和 9000 J/L 的液态血浆 UV-C 照射可有效防止 PRRSV 和其他病原体的传播。此外，原始液态血浆对 PCV-2 对天真猪无传染性。
