Abstract This study compared the effects of supplementation of postnatal Holstein dairy calves with low doses of zinc-methionine (Zn-Met) or zinc oxide (ZnO) on growth performance, diarrhea incidence, and the integrity of the small intestinal epithelial barrier. Twenty-four male newborn Holstein dairy calves with similar body weight (42.0 ± 1.2 kg) received raw milk and starter containing zinc at 4.05 mg/kg and 176 mg/kg dry matter, respectively. All animals were randomly allocated to one of three groups (n = 8 per group): a control group (CON, without extra zinc supplementation), a Zn-Met group (receiving 455 mg of Zn-Met per day, equivalent to 80 mg of zinc per day), or a ZnO group (receiving 103 mg of ZnO per day, equivalent to 80 mg of zinc per day). The experiment lasted for 14 days. Zn-Met and ZnO were mixed with milk and fed to the calves. Body weight, height, length, and heart girth were measured on the morning of days 1, 7, and 15. Feed intake and fecal scores were recorded daily during the experimental period. Blood samples were collected on day 15 before morning feeding. Thereafter, the animals were euthanized and their small intestines were collected for examination of intestinal morphology and the expression levels of mRNAs encoding jejunal mucosal tight junction (TJ) proteins. The two different sources of zinc did not influence growth performance or diarrhea incidence in dairy calves during days 1–7 or 1–14 after birth. However, Zn-Met supplementation reduced the diarrhea incidence (35.7 % [Zn-Met] vs. 58.9 % [CON]) and improved the average daily gain (ADG) (500 g/d [Zn-Met] vs. 422 g/d [CON]) and feed efficiency (feed-to-gain ratio: 2.05 [Zn-Met] vs. 2.47 [CON]) significantly during the second week after birth (P

中文翻译：

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锌-蛋氨酸通过保护产后荷斯坦奶牛的肠上皮屏障作为止泻剂

摘要 本研究比较了给出生后的荷斯坦奶牛补充低剂量的蛋氨酸锌 (Zn-Met) 或氧化锌 (ZnO) 对生长性能、腹泻发生率和小肠上皮屏障完整性的影响。24 头体重相近 (42.0 ± 1.2 kg) 的雄性新生荷斯坦奶牛接受了分别含有 4.05 mg/kg 和 176 mg/kg 干物质锌的生奶和发酵剂。所有动物被随机分配到三组中的一组（每组 n = 8）：对照组（CON，没有额外补充锌），Zn-Met 组（每天接受 455 mg Zn-Met，相当于 80 mg锌每天），或 ZnO 组（每天接受 103 毫克 ZnO，相当于每天 80 毫克锌）。实验持续了14天。Zn-Met 和 ZnO 与牛奶混合并喂给小牛。在第 1、7 和 15 天的早晨测量体重、身高、身长和心脏周长。在实验期间每天记录采食量和粪便评分。在早晨进食前的第 15 天收集血样。此后，将动物安乐死并收集它们的小肠以检查肠道形态和编码空肠黏膜紧密连接 (TJ) 蛋白的 mRNA 的表达水平。在出生后第 1-7 天或第 1-14 天期间，两种不同的锌来源不影响奶牛犊的生长性能或腹泻发生率。然而，Zn-Met 补充剂降低了腹泻发生率（35.7 % [Zn-Met] 对 58.9 % [CON]）并提高了平均日增重 (ADG)（500 g/d [Zn-Met] 对 422 g/ d [CON]) 和饲料效率（饲料/增重比：2.05 [Zn-Met] vs. 2。