A total of 360 weanling barrows (Line 200 ×400, DNA, Columbus NE; initially 5.6 ± 0.03 kg) were used in a 42-d study to evaluate yeast-based pre- and probiotics (Phileo by Lesaffre, Milwaukee, WI) in diets with or without pharmacological levels of Zn on growth performance and antimicrobial resistance (AMR) patterns of fecal Escherichia coli. Pens were assigned to one of four dietary treatments with five pigs per pen and 18 pens per treatment. Dietary treatments were arranged in a 2 × 2 factorial with main effects of yeast-based pre- and probiotics (none vs. 0.10% ActiSaf Sc 47 HR+, 0.05% SafMannan, and 0.05% NucleoSaf from days 0 to 7, then concentrations were lowered by 50% from days 7 to 21) and pharmacological levels of Zn (110 vs. 3,000 mg/kg from days 0 to 7, and 2,000 mg/kg from days 7 to 21 with added Zn provided by ZnO). All pigs were fed a common diet from days 21 to 42 post-weaning. There were no yeast ×Zn interactions or effects from yeast additives observed on any response criteria. From days 0 to 21 and 0 to 42, pigs fed pharmacological levels of Zn had increased (P < 0.001) ADG and ADFI. Fecal samples were collected on days 4, 21, and 42 from the same three pigs per pen for fecal dry matter (DM) and AMR patterns of E. coli. On day 4, pigs fed pharmacological levels of Zn had greater fecal DM (P = 0.043); however, no differences were observed on day 21 or 42. Escherichia coli was isolated from fecal samples and the microbroth dilution method was used to determine the minimal inhibitory concentrations (MIC) of E. coli isolates to 14 different antimicrobials. Isolates were categorized as either susceptible, intermediate, or resistant based on Clinical and Laboratory Standards Institute (CLSI) guidelines. The addition of pharmacological levels of Zn had a tendency (P = 0.051) to increase the MIC values of ciprofloxacin; however, these MIC values were still well under the CLSI classified resistant breakpoint for ciprofloxacin. There was no evidence for differences (P > 0.10) for yeast additives or Zn for AMR of fecal E. coli isolates to any of the remaining antibiotics. In conclusion, pharmacological levels of Zn improved ADG, ADFI, and all isolates were classified as susceptible to ciprofloxacin although the MIC of fecal E. coli tended to be increased. Thus, the short-term use of pharmacological levels of Zn did not increase antimicrobial resistance. There was no response observed from live yeast and yeast extracts for any of the growth, fecal DM, or AMR of fecal E. coli criteria.

中文翻译：

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含锌和不含锌的活酵母和酵母提取物对保育猪生长性能和粪便大肠杆菌的抗菌敏感性的影响

总共 360 头断奶仔猪（品系 200 × 400，DNA，Columbus NE；最初 5.6 ± 0.03 kg）被用于一项为期 42 天的研究，以评估基于酵母的益生菌和益生菌（Lesaffre，Milwaukee，WI 的 Phileo）在含有或不含锌的药理学水平对粪便大肠杆菌生长性能和抗菌素耐药性 (AMR) 模式的饮食。围栏被分配到四种日粮处理中的一种，每栏 5 头猪，每个处理 18 头猪。饮食处理安排在 2 × 2 阶乘中，主要作用是基于酵母的益生菌和益生菌（无对比 0.10% ActiSaf Sc 47 HR+、0.05% SafMannan 和 0.05% NucleoSaf，从第 0 天到第 7 天，然后降低浓度从第 7 天到第 21 天减少 50%）和锌的药理学水平（从第 0 天到第 7 天为 110 对 3,000 mg/kg，从第 7 天到第 21 天为 2,000 mg/kg，添加的 Zn 由 ZnO 提供）。从断奶后第 21 天到第 42 天，所有猪只饲喂普通日粮。在任何响应标准下均未观察到酵母 ×Zn 相互作用或酵母添加剂的影响。从第 0 天到第 21 天和第 0 天到第 42 天，猪饲喂药理水平的锌增加了 (P < 0.001) ADG 和 ADFI。在第 4 天、第 21 天和第 42 天，从每栏相同的三头猪身上收集粪便样本，用于粪便干物质 (DM) 和大肠杆菌的 AMR 模式。第 4 天，饲喂药理水平锌的猪粪便干物质更高（P = 0.043）；然而，在第 21 天或第 42 天没有观察到差异。从粪便样本中分离出大肠杆菌，并使用微量肉汤稀释法确定大肠杆菌分离株对 14 种不同抗菌剂的最小抑菌浓度 (MIC)。分离株被归类为易感、中间、或根据临床和实验室标准协会 (CLSI) 指南产生耐药性。添加药理学水平的 Zn 有增加环丙沙星 MIC 值的趋势 (P = 0.051)；然而，这些 MIC 值仍远低于 CLSI 分类的环丙沙星耐药断点。没有证据表明酵母添加剂或 Zn 对粪便大肠杆菌分离株的 AMR 与任何其他抗生素存在差异 (P > 0.10)。总之，Zn 的药理学水平提高了 ADG、ADFI，并且所有分离株都被归类为对环丙沙星敏感，尽管粪便大肠杆菌的 MIC 趋于增加。因此，短期使用药理水平的锌不会增加抗菌素耐药性。没有观察到活酵母和酵母提取物对任何生长、粪便 DM、