Enterotoxigenic Escherichia coli (ETEC), being the major cause of post-weaning diarrhoea (PWD) in newly weaned piglets, induces poor performance and economic losses in pig production. This functional in vitro screening study investigated probiotic strains for use in suckling piglets as a prophylactic strategy towards PWD. Nine strains were evaluated based on their ability to: enhance intestinal epithelial barrier function, reduce adherence of ETEC F18 to intestinal cells, inhibit growth of ETEC F18, and grow on porcine milk oligosaccharides. Strains included in the screening were of the species Lactobacillus, Enterococcus, Bifidobacterium and Bacillus. Our in vitro screening demonstrated genus-, species and strain-specific differences in the mode of action of the tested probiotic strains. Some of the tested bifidobacteria were able to grow on the two porcine milk oligosaccharides, 3′-sialyllactose sodium salt (3’SL) and Lacto-N-neotetraose (LNnT), whereas most lactic acid bacteria strains and both Bacillus subtilis strains failed to do so. All probiotic strains inhibited growth of ETEC F18 on agar plates. All but the bifidobacteria reduced binding of ETEC F18 to Caco-2 cell monolayers, with the Enterococcus faecium strain having the most profound effect. All three lactic acid bacteria and Bifidobacterium animalis subsp. lactis counteracted the ETEC F18-induced permeability across Caco-2 cell monolayers with the E. faecium strain exhibiting the most pronounced protective effect. The findings from this in vitro screening study indicate that, when selecting probiotic strains for suckling piglets as a prophylactic strategy towards PWD, it would be advantageous to choose a multi-species product including strains with different modes of action in order to increase the likelihood of achieving beneficial effects in vivo.

产肠毒素大肠杆菌(ETEC) 是新断奶仔猪断奶后腹泻 (PWD) 的主要原因，会导致生猪生产性能不佳和经济损失。这项功能性体外筛选研究调查了用于哺乳仔猪的益生菌菌株，作为预防 PWD 的策略。根据以下能力对九种菌株进行了评估：增强肠上皮屏障功能、减少 ETEC F18 对肠细胞的粘附、抑制 ETEC F18 的生长以及在猪乳寡糖上生长。筛选中包括的菌株是乳杆菌属、肠球菌属、双歧杆菌属和芽孢杆菌属。我们的体外筛选证明了所测试益生菌菌株的作用方式存在属、种和菌株特异性差异。一些被测试的双歧杆菌能够在两种猪乳低聚糖、3'-唾液酸乳糖钠盐 (3'SL) 和乳-N-新四糖 (LNnT) 上生长，而大多数乳酸菌菌株和两种枯草芽孢杆菌菌株均未能这样做。所有益生菌菌株均抑制 ETEC F18 在琼脂平板上的生长。除双歧杆菌外，所有细菌都降低了 ETEC F18 与 Caco-2 细胞单层的结合，其中屎肠球菌菌株具有最深远的影响。所有三种乳酸菌和动物双歧杆菌亚种。乳酸菌抵消了 ETEC F18 诱导的 Caco-2 细胞单层渗透性，其中屎肠球菌菌株表现出最显着的保护作用。这项体外筛选研究的结果表明，当为哺乳仔猪选择益生菌菌株作为 PWD 的预防策略时，选择包括具有不同作用模式的菌株在内的多物种产品以增加感染的可能性将是有利的。在体内取得有益效果。