The goals of this study were to determine the impact of maternal PRRSV infection on offspring muscle and immune development and the potential of dietary soy isoflavones to mitigate those effects. Thirteen first-parity gilts (“gilts”) were randomly allotted into one of three treatments: not infected and fed a diet devoid of isoflavones (CON), infected with porcine reproductive and respiratory syndrome virus (PRRSV) and fed the control diet (POS) or that supplemented with 1,500 mg/kg soy-derived isoflavones (ISF). Gilts were inoculated with PRRSV intranasally on gestational day (GD) 70. After farrowing (GD 114 ± 2), 1-2 offspring (“pigs”) closest to the average litter weight were selected either at birth (3 ± 2 d of age) or weaning (21 ±2 d of age) to determine body, muscle, and organ weights as well as muscle cell number and size. Four weaned pigs of average body weight within each litter were selected for postnatal immune challenge. At PND 52, pigs were injected with 5 µg/kg BW lipopolysaccharide (LPS) intraperitoneally. Serum was collected at 0, 4, and 8 h following LPS administration to analyze tumor necrosis factor alpha (TNF-α). At PND 59, pigs were administered a novel vaccine to elicit an adaptive immune response. At PND 59, 66, and 73, peripheral blood mononuclear cells were isolated and T-cell populations determined by flow cytometry. Both POS and ISF pigs exhibited persistent PRRSV infections throughout the study (PND 1-73). At PND 3, whole body, muscle, and organ weights were not different (P > 0.22) between groups, with the exception of relative liver weight, which was increased (P < 0.05) in POS compared with CON pigs. At PND 21, ISF pigs had reduced (P ≤ 0.05) whole body and muscle weights, but greater (P < 0.05) kidney weight compared with CON, and greater (P < 0.05) relative liver weight compared with CON and POS. Muscle fiber number and size were not different (P > 0.39) between groups at birth or weaning. After LPS administration, TNF-α was greatest in ISF pigs (P < 0.05) at both 0 and 8 h post-challenge. At the peak time-point of 4 h post-challenge, ISF pigs had the greatest concentration of TNF-α and CON pigs had the lowest, with POS pigs being intermediate (P = 0.01). After vaccination, ISF offspring had shifts in T-cell populations indicating an impaired immune response. These data indicate that maternal PRRSV infection may impact offspring organ growth and immune function, particularly when the dam is supplemented with isoflavones.

中文翻译：

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母体免疫激活和日粮大豆异黄酮补充剂影响猪免疫功能但不影响肌纤维形成

本研究的目的是确定母体 PRRSV 感染对后代肌肉和免疫发育的影响，以及膳食大豆异黄酮减轻这些影响的潜力。13 头母猪（“小母猪”）被随机分配到三种治疗中的一种：未感染并喂食不含异黄酮的饮食 (CON)，感染猪繁殖与呼吸综合征病毒 (PRRSV) 并喂食对照饮食 (POS) ) 或补充了 1,500 mg/kg 大豆异黄酮 (ISF)。后备母猪在妊娠第 70 天 (GD) 经鼻接种 PRRSV。分娩后 (GD 114 ± 2)，选择出生时（3 ± 2 日龄）最接近平均窝重的 1-2 头后代（“猪”） ) 或断奶（21 ±2 日龄）以确定身体、肌肉和器官的重量以及肌肉细胞的数量和大小。每窝中选择四头平均体重的断奶猪用于产后免疫攻击。在 PND 52，猪腹腔注射 5 µg/kg BW 脂多糖 (LPS)。在 LPS 给药后 0、4 和 8 小时收集血清以分析肿瘤坏死因子 α (TNF-α)。在 PND 59，给猪注射了一种新型疫苗以引发适应性免疫反应。在 PND 59、66 和 73 时，分离外周血单核细胞并通过流式细胞术测定 T 细胞群。POS 和 ISF 猪在整个研究过程中都表现出持续的 PRRSV 感染（PND 1-73）。在 PND 3 时，全身、肌肉和器官重量在各组之间没有差异 (P > 0.22)，但相对肝脏重量除外，与 CON 猪相比，POS 中的相对肝脏重量有所增加 (P < 0.05)。在 PND 21，与 CON 相比，ISF 猪的全身重量和肌肉重量降低 (P ≤ 0.05)，但肾脏重量增加 (P < 0.05)，与 CON 和 POS 相比，相对肝脏重量增加 (P < 0.05)。出生或断奶时各组之间的肌纤维数量和大小没有差异 (P > 0.39)。施用 LPS 后，ISF 猪中的 TNF-α 在攻击后 0 小时和 8 小时均最高 (P < 0.05)。在攻击后 4 小时的峰值时间点，ISF 猪的 TNF-α 浓度最高，CON 猪最低，POS 猪居中（P = 0.01）。接种疫苗后，ISF 后代的 T 细胞群发生变化，表明免疫反应受损。这些数据表明母体 PRRSV 感染可能影响后代器官生长和免疫功能，尤其是当母体补充了异黄酮时。