Post-weaned piglets suffer from F18+ Escherichia coli (E. coli) infections resulting in post-weaning diarrhoea or oedema disease. Frequently used management strategies, including colistin and zinc oxide, have contributed to the emergence and spread of antimicrobial resistance. Novel antimicrobials capable of directly interacting with pathogens and modulating the host immune responses are being investigated. Lactoferrin has shown promising results against porcine enterotoxigenic E. coli strains, both in vitro and in vivo. We investigated the influence of bovine lactoferrin (bLF) on the microbiome of healthy and infected weaned piglets. Additionally, we assessed whether bLF influenced the immune responses upon Shiga toxin-producing E. coli (STEC) infection. Therefore, 2 in vivo trials were conducted: a microbiome trial and a challenge infection trial, using an F18+ STEC strain. BLF did not affect the α- and β-diversity. However, bLF groups showed a higher relative abundance (RA) for the Actinobacteria phylum and the Bifidobacterium genus in the ileal mucosa. When analysing the immune response upon infection, the STEC group exhibited a significant increase in F18-specific IgG serum levels, whereas this response was absent in the bLF group. Taken together, the oral administration of bLF did not have a notable impact on the α- and β-diversity of the gut microbiome in weaned piglets. Nevertheless, it did increase the RA of the Actinobacteria phylum and Bifidobacterium genus, which have previously been shown to play an important role in maintaining gut homeostasis. Furthermore, bLF administration during STEC infection resulted in the absence of F18-specific serum IgG responses.

中文翻译：

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探索牛乳铁蛋白对健康和产志贺毒素大肠杆菌攻击的断奶仔猪微生物组和免疫反应的调节作用

断奶后仔猪遭受 F18+ 大肠杆菌 (E. coli) 感染，导致断奶后腹泻或水肿病。经常使用的管理策略，包括粘菌素和氧化锌，导致了抗菌素耐药性的出现和传播。能够直接与病原体相互作用并调节宿主免疫反应的新型抗菌剂正在研究中。乳铁蛋白在体外和体内均显示出对抗猪产肠毒素大肠杆菌菌株的良好效果。我们研究了牛乳铁蛋白 (bLF) 对健康和受感染断奶仔猪微生物组的影响。此外，我们还评估了 bLF 是否影响产志贺毒素大肠杆菌 (STEC) 感染时的免疫反应。因此，进行了 2 项体内试验：微生物组试验和攻击感染试验，使用 F18+ STEC 菌株。BLF 不影响α-和β-多样性。然而，bLF 组在回肠粘膜中显示出较高的放线菌门和双歧杆菌属的相对丰度（RA）。在分析感染后的免疫反应时，STEC 组表现出 F18 特异性 IgG 血清水平显着增加，而 bLF 组则没有这种反应。综上所述，口服 bLF 对断奶仔猪肠道微生物群的 α 和 β 多样性没有显着影响。尽管如此，它确实增加了放线菌门和双歧杆菌属的 RA，此前已证明它们在维持肠道稳态中发挥着重要作用。此外，STEC 感染期间施用 bLF 导致 F18 特异性血清 IgG 反应缺失。