To evaluate the effects of crude protein (CP) and lactose (LAC) for weaned piglets on performance, intestinal morphology, and expression of genes related to intestinal integrity and immune system, 144 piglets with initial weight 7.17 ± 0.97 kg were allotted in a randomized design, in a 2 × 3 factorial arrangement (20.0% and 24.0% CP and 8.0%, 12.0%, and 16.0% LAC) with eight replicates. Piglets fed 20.0% CP had greater weight gain and feed intake. Including 12.0% LAC in the 20.0% CP diet provided higher villous height in the duodenum than 8.0% LAC, and 12.0% or 16.0% LAC in the 24.0% CP diet resulted in higher villous height in the jejunum and ileum, and higher villi/crypt ratio in the ileum than 8.0% LAC. No effects of CP and LAC on interleukin‐1β and tumor necrosis factor‐α mRNA were observed. The 16.0% LAC diet provided higher gene expression of transforming‐β1 growth factor. Feeding 20.0% CP resulted in better performance than 24.0% CP. The 12.0% LAC diet promoted greater genetic expression of occludin and zonula occludens. Including 12.0% LAC in the diet may improve intestinal epithelial morphology and integrity, and these improvements are more evident when piglets are fed diets with 24.0% CP.

中文翻译：

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日粮中粗蛋白和乳糖水平对断奶仔猪生长性能、肠道形态、肠道完整性和免疫系统相关基因表达的影响。

为了评估粗蛋白 (CP) 和乳糖 (LAC) 对断奶仔猪的性能、肠道形态以及与肠道完整性和免疫系统相关的基因表达的影响，将 144 头初始体重为 7.17 ± 0.97 kg 的仔猪分配到一个随机分组中设计，采用 2 × 3 因子排列（20.0% 和 24.0% CP 以及 8.0%、12.0% 和 16.0% LAC），重复八次。饲喂 20.0% CP 的仔猪增重和采食量更高。在 20.0% CP 饮食中包含 12.0% LAC 的十二指肠绒毛高度高于 8.0% LAC，而在 24.0% CP 饮食中包含 12.0% 或 16.0% LAC 导致空肠和回肠中较高的绒毛高度，以及较高的绒毛/回肠隐窝比LAC高8.0%。未观察到 CP 和 LAC 对白介素-1β 和肿瘤坏死因子-α mRNA 的影响。16。0% LAC 饮食提供了更高的转化-β1 生长因子基因表达。饲喂 20.0% CP 的性能优于 24.0% CP。12.0% LAC 饮食促进了 occludin 和 zonula occludens 的更大基因表达。在日粮中添加 12.0% LAC 可改善肠上皮形态和完整性，当仔猪饲喂 24.0% CP 日粮时，这些改善更为明显。