Sialyllactose (SL) is one of the most abundant oligosaccharides present in porcine breast milk. However, little is known about its effect on growth performance and intestinal health in weaned pigs. This study was conducted to explore the protective effect of SL on intestinal epithelium in weaned pigs upon enterotoxigenic Escherichia coli (ETEC) challenge. Thirty-two pigs were randomly divided into four treatments. Pigs fed with a basal diet or basal diet containing SL (5.0 g/kg) were orally infused with ETEC or culture medium. SL supplementation elevated the average daily gain (ADG) and feed efficiency in the ETEC-challenged pigs (P < 0.05). SL also improved the digestibilities of dry matter (DM), gross energy (GE), and ash in non-challenged pigs (P < 0.05). Moreover, SL not only elevated serum concentrations of immunoglobulins (IgA, IgG, and IgM), but also significantly decreased the serum concentrations of inflammatory cytokines (TNF-α, IL-1β, and IL-6) upon ETEC challenge (P < 0.05). Interestingly, SL increased the villus height, the ratio of villus height to crypt depth (V:C), and the activities of mucosal sucrase and maltase in the jejunum and ileum (P < 0.05). SL also elevated the concentrations of microbial metabolites (e.g. acetic acid, propanoic acid, and butyric acid) and the abundance of Lactobacillus, Bifidobacterium, and Bacillus in the cecum (P < 0.05). Importantly, SL significantly elevated the expression levels of jejunal zonula occludins-1 (ZO-1), occluding, and fatty acid transport protein-4 (FATP4) in the ETEC-challenged pigs (P < 0.05). SL can alleviate inflammation and intestinal injury in weaned pigs upon ETEC challenge, which was associated with suppressed secretion of inflammatory cytokines and elevated serum immunoglobulins, as well as improved intestinal epithelium functions and microbiota.

中文翻译：

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唾液酸乳糖对产肠毒素大肠埃希菌攻击断奶仔猪生长性能和肠上皮功能的影响

唾液酸乳糖 (SL) 是猪母乳中含量最丰富的低聚糖之一。然而，关于它对断奶仔猪生长性能和肠道健康的影响知之甚少。本研究旨在探讨 SL 对产肠毒素大肠杆菌 (ETEC) 攻击的断奶仔猪肠道上皮细胞的保护作用。32头猪被随机分为4个处理。饲喂基础日粮或含 SL (5.0 g/kg) 的基础日粮的猪口服 ETEC 或培养基。SL 补充剂提高了 ETEC 攻击猪的平均日增重 (ADG) 和饲料效率 (P < 0.05)。SL 还提高了非攻击猪的干物质 (DM)、总能量 (GE) 和灰分的消化率 (P < 0.05)。此外，SL 不仅提高血清免疫球蛋白（IgA、IgG、和 IgM），但也显着降低了 ETEC 攻击后炎症细胞因子（TNF-α、IL-1β 和 IL-6）的血清浓度（P < 0.05）。有趣的是，SL增加了绒毛高度、绒毛高度与隐窝深度的比值（V:C）以及空肠和回肠黏膜蔗糖酶和麦芽糖酶的活性（P < 0.05）。SL 还提高了盲肠中微生物代谢物（例如乙酸、丙酸和丁酸）的浓度和乳酸杆菌、双歧杆菌和芽孢杆菌的丰度（P < 0.05）。重要的是，SL 显着提高了 ETEC 攻击猪的空肠小带 occludins-1 (ZO-1)、封闭蛋白和脂肪酸转运蛋白 4 (FATP4) 的表达水平 (P < 0.05)。SL 可以减轻 ETEC 攻击后断奶仔猪的炎症和肠道损伤，