Programa de Pós-graduação Em Zootecnia, Universidade do Estado de Santa Catarina, Brazil.
Programa de Pós-graduação Em Zootecnia, Universidade do Estado de Santa Catarina, Brazil; Programa de Pós-graduação Em Bioquímica Toxicologica, Universidade Federal de Santa Maria, Brazil.
Microb Pathog. 2019 May;130:131-136. doi: 10.1016/j.micpath.2019.03.004. Epub 2019 Mar 8.
The objective of this study was to evaluate the productive impact of colibacillosis on laying hens and to investigate whether energetic metabolism and oxidative stress were involved in the pathogenesis of the disease. An experimental shed containing 270 laying hens of the Hy-Line lineage (32 weeks old) presented approximately 40% daily laying, and many birds presented with diarrhea and apathy followed by death. Necropsy revealed macroscopic lesions compatible with colibacillosis and infectious agent Escherichia coli was isolated from fecal samples of all birds in the infected group, as well as from tissue (ovary, liver and peritoneum). Sixteen chickens were selected for this study, divided into two groups: Control (animals without clinical alterations) and infected (with diarrhea and apathetic). E. coli isolates were subjected to the antimicrobial susceptibility testing according to the methodology approved by CLSI, 2018. This testing showed sensitivity to gentamicin, amoxicillin, norfloxacin and colistin. It was then determined that laying hens would be treated with norfloxacin (15 mg/kg) diluted in water offered at will to the birds for three days. Blood collections were performed via brachial vein after the diagnosis of E. coli (before starting treatment) and seven days after treatment. Three debilitated chickens died on the second day after initiating therapy. Before treatment, birds with clinical signs had higher levels of lipoperoxidation (LPO) and activities of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx) than in the control group (asymptomatic animals). After treatment, LPO levels remained higher in birds that had clinical disease (infected group), whereas the activity of SOD and GPx enzymes did not differ between groups. Activity levels of creatine kinase (CK) and pyruvate kinase (PK) were higher in the group of chickens with clinical disease before treatment. Post-treatment, no differences were observed between groups in terms of CK; however, PK activity remained high in these animals. In the hens that died, there were lesions characteristic of avian colibacillosis, with ovary involvement, explaining the low laying activity of the birds at their peak of production. For 10 days after starting treatment, the percentage of laying increased to 90%. Therefore, we conclude that colibacillosis interferes with the phosphotransfer network by stimulating ATP production, in addition to causing oxidative stress of the birds during laying, that negatively affects health and productive efficiency.
本研究旨在评估大肠杆菌病对蛋鸡的生产影响，并探讨能量代谢和氧化应激是否与疾病的发病机制有关。一个包含 270 只海兰系（32 周龄）蛋鸡的实验棚，每天的产蛋率约为 40%，许多鸡出现腹泻和无精打采，随后死亡。剖检显示，病变与大肠杆菌病一致，从感染组所有鸡的粪便样本以及组织（卵巢、肝脏和腹膜）中分离出大肠杆菌。本研究选择了 16 只鸡，分为两组：对照组（无临床变化的动物）和感染组（有腹泻和无精打采）。按照 CLSI，2018 年批准的方法对大肠杆菌分离株进行了药敏试验。药敏试验显示对庆大霉素、阿莫西林、诺氟沙星和黏菌素敏感。然后，决定用诺氟沙星（15mg/kg）对蛋鸡进行治疗，将诺氟沙星稀释在水中，供鸡自由饮用，为期三天。在大肠杆菌诊断后（开始治疗前）和治疗后七天，通过肱静脉进行血液采集。在开始治疗的第二天，三只虚弱的鸡死亡。在治疗前，有临床症状的鸡的脂质过氧化（LPO）水平和抗氧化酶超氧化物歧化酶（SOD）和谷胱甘肽过氧化物酶（GPx）的活性高于对照组（无症状动物）。治疗后，临床疾病鸡（感染组）的 LPO 水平仍然较高，而 SOD 和 GPx 酶的活性在两组之间没有差异。在治疗前有临床疾病的鸡的肌酸激酶（CK）和丙酮酸激酶（PK）活性水平较高。治疗后，两组之间 CK 无差异，但这些动物的 PK 活性仍然较高。在死亡的母鸡中，有典型的禽大肠杆菌病病变，涉及卵巢，这解释了母鸡在产蛋高峰期产蛋活动减少的原因。治疗开始后 10 天，产蛋率增加到 90%。因此，我们得出结论，大肠杆菌病通过刺激 ATP 产生来干扰磷酸转移网络，此外，还会在母鸡产蛋期间引起氧化应激，这对其健康和生产效率产生负面影响。
