Abstract：
In this study, we compared the impacts of Bacillus subtilis PB6 (BS) and bacitracin methylene disalicylate (BMD) on the growth performance, intestinal morphology, expression of tight connection protein, and cecal microbiota community of male ducks through a 42-d trial. Three-hundred and sixty male Cherry Valley meat-type ducklings (1-day-old) were distributed into 3 groups of 6 replicates: CON group (control, basal diet), BMD group (basal diet + 45 mg/kg BMD, active ingredient dose in the feed), and BS group (basal diet + 2 × 107 CFU/kg BS in the feed). Results showed that supplementing the diet with BS reduced the average daily feed intake (ADFI) during d 15 to 42 and d 1 to 42 compared with the CON group (P = 0.032). It also reduced feed conversion ratio (FCR) during d 15 to 42 and d 1 to 42 (P < 0.05) relative to the other groups. The ileal villus height (VH) and villus height /crypt depth ratio (V/C) were increased (P < 0.05) in both the BS and BMD groups, and the jejunal VH and V/C ratio were increased in the BS group (P < 0.05). Relative to the CON, BS supplementation was associated with numerical augmentation of goblet cells in the jejunal mucosa and upregulation of jejunal zonula occludens (ZO-1) and ileal mucin2 (P < 0.05) mRNA levels. Analysis showed a negative correlation between FCR (d 0-42) and VH, V/C, and the number of goblet cells in the jejunum (P < 0.05). Additionally, BMD or BS supplementation altered the alpha diversity of colonic microbiota (P < 0.05). Correlation analysis revealed that Butyricimonas, Enterobacteriaceae, Clostridiaceae, and Tannerellaceae were positively associated with the acetic acid and butyrate concentrations (P < 0.05). Taken together, the supplementation of BS in the diet of male ducks was conducive to reducing FCR by meliorating intestinal morphology, upregulating ZO-1 and mucin2 mRNA levels, regulating the abundance of microbiota, and metabolites, and having a greater effect than BMD supplementation.
摘要：
在这项研究中,我们比较了枯草芽孢杆菌PB6（BS）和杆菌肽亚甲基二水杨酸（BMD）对生长性能的影响，肠道形态学,紧密连接蛋白的表达，通过42天的试验，雄性鸭子的盲肠微生物群落。将三百六十个雄性樱桃谷肉型鸭（1日龄）分为3组，每组6个重复：CON组（对照组，基础饮食)，BMD组（基础饮食+45mg/kgBMD，饲料中的活性成分剂量)，和BS组(基础日粮+2×107CFU/kg饲料中的BS)。结果表明，与CON组相比，在第15至42天和第1至42天，饲粮中添加BS降低了平均日采食量（ADFI）（P=0.032）。相对于其他组，它还降低了d15至42和d1至42期间的饲料转化率（FCR）（P<0.05）。BS组和BMD组回肠绒毛高度（VH）和绒毛高度/隐窝深度比（V/C）均增加（P<0.05）。BS组空肠VH和V/C比值升高(P<0.05)。相对于CON,补充BS与空肠粘膜杯状细胞的数量增加以及空肠闭塞性带（ZO-1）和回肠粘蛋白2（P<0.05）mRNA水平的上调有关。分析显示FCR(D0-42)与VH呈负相关,V/C,空肠杯状细胞数(P<0.05)。此外,补充BMD或BS改变了结肠微生物群的α多样性(P<0.05)。相关分析表明,肠杆菌科,梭菌科，和制革菌与乙酸和丁酸浓度呈正相关(P<0.05)。一起来看,在雄鸭的日粮中补充BS有利于通过改善肠道形态来降低FCR，上调ZO-1和粘蛋白2mRNA水平，调节微生物群的丰度，和代谢物，具有比BMD补充更大的效果。
