Progeny born to primiparous sows (gilt progeny; GP) have lower birth, weaning and slaughter weights than sow progeny (SP). GP also have reduced gastrointestinal tract (GIT) development, as evidenced by lower organ weights. Therefore, the aim of this experiment was to quantify changes in GIT barrier function that occur birth and weaning, representing two major challenges to the young piglet. The effects of parity (GP vs SP) in GIT barrier integrity function was quantified at four timepoints: birth (~0 h), 24 hours after birth (24 h), 1-day pre-weaning (PrW) and 1-day post-weaning (PoW) in commercially reared piglets. Due to inherent differences between newborn and weanling pigs the results were analyzed in two cohorts, birth (0 vs. 24 h, n = 31) and weaning (PrW vs. PoW, n = 40). Samples of the stomach, jejunum, ileum and colon were excised after euthanasia and barrier integrity was quantified by measuring transepithelial resistance (TER), macromolecular permeability, the abundance of inflammatory proteins (IL-8, IL-1β, TNF-α) and tight junction proteins (claudin-2 and -3). Papp was characterised using a dual tracer approach comprising 4 KDa fluorescein isothiocyanate (FD4) and 150 kDa tetramethyl rhodamine isothiocyanate (T150)-labelled dextrans. Characteristic effects of the initiation of feeding and weaning were observed on the GIT with the initiation of feeding, such as increasing TER and reducing Papp at 24 h, consistent with mucosal growth (p = 0.058) This was accompanied by increased cytokine abundance as evidenced by elevations in TNF-α and IL-1β. However, GP had increased IL-8 abundance (p = 0.011 and 0.063 for jejunum and ileum respectively) at birth than 24 h overall. In the weaning cohort, jejunal and ileal permeability to FD4 was higher in GP (p = 0.05 and 0.022, respectively) while only higher ileal T150 was observed in GP (p = 0.032). Ileal claudin-2 abundance tended to be higher in SP overall (p = 0.063), but GP ileal claudin-2 expression was upregulated weaning while no change was observed in SP (p = 0.043). Finally, other than a higher jejunal TNF-α abundance observed in SP (p = 0.016), no other effect of parity was observed on inflammatory markers in the weaning cohort. The results from this study indicate that the GIT of GP have poorer adaptation to early life events, with the response to weaning, being more challenging which is likely to contribute to poorer post-weaning growth.

中文翻译：

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后备母猪与母猪后代出生和断奶时胃肠道屏障功能和免疫标志物的比较分析

初产母猪所生的后代（后备母猪后代；GP）的出生体重、断奶体重和屠宰体重均低于母猪后代（SP）。GP 还降低了胃肠道 (GIT) 的发育，器官重量降低就证明了这一点。因此，本实验的目的是量化出生和断奶时胃肠道屏障功能的变化，这是幼仔面临的两大挑战。在四个时间点量化胎次（GP 与 SP）对 GIT 屏障完整性功能的影响：出生（~0 小时）、出生后 24 小时（24 小时）、断奶前 1 天（PrW）和断奶后 1 天-商业饲养仔猪的断奶（PoW）。由于新生猪和断奶仔猪之间存在固有差异，因此在出生（0 vs. 24 小时，n = 31）和断奶（PrW vs. PoW，n = 40）这两个队列中对结果进行了分析。安乐死后切除胃、空肠、回肠和结肠的样本，并通过测量跨上皮阻力（TER）、大分子通透性、炎症蛋白（IL-8、IL-1β、TNF-α）的丰度和紧密度来量化屏障完整性。连接蛋白（claudin-2 和 -3）。使用双示踪剂方法对 Papp 进行表征，该方法包含 4 KDa 异硫氰酸荧光素 (FD4) 和 150 kDa 四甲基罗丹明异硫氰酸酯 (T150) 标记的葡聚糖。随着开始喂养，观察到开始喂养和断奶对 GIT 的特征性影响，例如 24 小时时 TER 增加和 Papp 减少，这与粘膜生长一致 (p = 0.058) 这伴随着细胞因子丰度的增加，如下所示： TNF-α 和 IL-1β 升高。然而，出生后 24 小时内，GP 的 IL-8 丰度有所增加（空肠和回肠分别 p = 0.011 和 0.063）。在断奶队列中，GP 中空肠和回肠对 FD4 的渗透性较高（分别为 p = 0.05 和 0.022），而 GP 中仅观察到回肠 T150 较高（p = 0.032）。SP 中回肠claudin-2 丰度总体较高（p = 0.063），但断奶后GP 回肠claudin-2 表达上调，而SP 中未观察到变化（p = 0.043）。最后，除了在 SP 中观察到较高的空肠 TNF-α 丰度（p = 0.016）外，在断奶队列中没有观察到胎次对炎症标志物的其他影响。这项研究的结果表明，GP的胃肠道对早期生活事件的适应能力较差，对断奶的反应更具挑战性，这可能导致断奶后生长较差。