Antibiotics are generally applied for treatment or as subtherapeutic agents to overcome diseases caused by pathogenic bacteria including Escherichia coli, Salmonella and Enterococcus species in poultry. However, due to their possible adverse effects on animal health and to maintain food safety, probiotics, prebiotics, and synbiotics have been proposed as alternatives to antibiotic growth promoters (AGPs) in poultry production. In this study, the effects of prebiotics on the augmentation of broiler’s indigenous gut microbiology were studied. Day old 180 broilers chicks were divided into four treatment groups: G, L, C1, and C2. The groups G and L were fed with basal diet containing 3% dextran and 3% levan, respectively. Control groups were fed with basal diets without antibiotic (C1) and with antibiotics (C2). The experimental groups showed decreased mortality as compared to control groups. After 35 days, the chickens were euthanized and intestinal fluid was analyzed for enteric pathogens on chromogenic agar plates and by 16S rRNA gene sequencing. Inhibition of the growth of E. coli and Enterococcus was observed in groups G and L, respectively, whereas Salmonella was only present in group C1. Also, high populations of lactic acid bacteria were detected in the intestine of prebiotic fed birds as compared to controls. These results depict that dextran and levan have the potential to replace the use of antibiotics in poultry feed for inhibiting the growth of common enteric pathogens. To the best of our knowledge, this is the first study where effects of dextran and levan on intestinal microbiota of broilers have been reported.

中文翻译：

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微生物产生的葡聚糖和左旋多糖对肉鸡肠道中常见肠道病原体的生长抑制

抗生素通常用于治疗或作为亚治疗剂来克服家禽中由大肠杆菌、沙门氏菌和肠球菌等致病菌引起的疾病。然而，由于它们可能对动物健康和维持食品安全产生不利影响，益生菌、益生元和合生元已被提议作为家禽生产中抗生素生长促进剂 (AGP) 的替代品。在本研究中，研究了益生元对增强肉鸡固有肠道微生物学的影响。日龄 180 只肉鸡被分成四个处理组：G、L、C1 和 C2。G组和L组分别用含有3%右旋糖酐和3%左旋糖酐的基础饲料喂养。对照组饲喂不含抗生素 (C1) 和抗生素 (C2) 的基础日粮。与对照组相比，实验组的死亡率降低。35 天后，对鸡实施安乐死，并在显色琼脂平板上通过 16S rRNA 基因测序分析肠液中的肠道病原体。分别在 G 和 L 组中观察到大肠杆菌和肠球菌的生长受到抑制，而沙门氏菌仅存在于 C1 组中。此外，与对照组相比，在益生元喂养的鸟类的肠道中检测到大量乳酸菌。这些结果表明，葡聚糖和果聚糖有可能取代抗生素在家禽饲料中的使用，以抑制常见肠道病原体的生长。据我们所知，这是第一项报道了葡聚糖和果聚糖对肉鸡肠道微生物群影响的研究。