1. The present study focused on the potential effects of antibiotics on intestinal digestion and integrity in broilers in terms of disaccharidase activity, electrophysiological properties and morphology.

2. One-day-old Arbour Acres birds were randomly allocated to one of four treatment groups for 42 days; control, colistin (20 mg/kg), tylosin (55 mg/kg) or chlortetracycline (CTC, 55 mg/kg) groups. Colistin and tylosin supplementation, but not CTC supplementation, caused an increase in body weight gain.

3. Colistin and tylosin elevated the activities of maltase and sucrase in the mucosa of the jejunum on d 42. Age caused a gradual decrease in the short-circuit current (Isc) and conductance (Gt) of the ileum, as a measure of permeability. The Isc and Gt of the ileum were higher in the colistin-supplemented broilers than in the control birds on d 42. Tylosin- and CTC-supplemented birds displayed Isc and Gt values similar to those of the control birds.

4. Colistin supplementation increased the villus area in the jejunum and thinned the muscularis mucosae in the ileum compared with the control group. Tylosin supplementation decreased the thickness of the muscularis mucosae and the depth of crypt in the jejunum. CTC thickened the muscularis mucosae in the jejunum and ileum.

5. Colistin and tylosin exhibited a beneficial effect on intestinal digestion and integrity by enhancing disaccharidase activities and improving gut morphology and permeability.

1. 本研究重点关注抗生素对肉鸡肠道消化和完整性的潜在影响，包括双糖酶活性、电生理特性和形态。

2. 一天大的 Arbor Acres 鸡被随机分配到四个治疗组之一，持续 42 天；对照组、粘菌素 (20 mg/kg)、泰乐菌素 (55 mg/kg) 或金霉素 (CTC, 55 mg/kg) 组。补充粘菌素和泰乐菌素，而不是补充 CTC，导致体重增加。

3. 粘菌素和泰乐菌素在第 42 天提高了空肠黏膜中麦芽糖酶和蔗糖酶的活性。年龄导致回肠短路电流 (Isc) 和电导 (Gt) 逐渐降低，作为通透性的衡量标准. 在第 42 天，添加粘菌素的肉鸡回肠的 Isc 和 Gt 高于对照鸡。添加泰乐菌素和 CTC 的鸡的 Isc 和 Gt 值与对照鸡相似。

4.与对照组相比，补充粘菌素增加了空肠绒毛面积，使回肠黏膜肌层变薄。泰乐菌素补充剂降低了黏膜肌层的厚度和空肠隐窝的深度。CTC 使空肠和回肠的黏膜肌层增厚。

5. 粘菌素和泰乐菌素通过增强双糖酶活性和改善肠道形态和通透性，对肠道消化和完整性具有有益作用。