Manning J G, Hargis B M, Hinton A, Corrier D E, DeLoach J R, Creger C R
Department of Poultry Science, Texas A&M University, College Station 77843.
Avian Dis. 1994 Apr-Jun;38(2):256-61.
One-day-old leghorn chicks were placed in floor pens on previously used poultry litter (potentially providing exposure to normal chicken enteric flora) for 7 days and provided feed containing one of several antibiotics or anticoccidials. On day 7, all groups were challenged orally with an isolate of Salmonella enteritidis (10(6) colony-forming units) that was resistant to bacitracin, novobiocin, nalidixic acid, and nitrofurazone. All chicks were killed on day 13, and liver, spleen, and cecal tonsils were cultured. Dietary administration of novobiocin (0.385 g/kg) caused a significant increase (P < 0.05) in positive chick colonization rate (either liver and spleen or cecal tonsils) compared with the unmedicated controls. Similarly, chicks administered dietary nitrofurazone (0.3 g/kg) were infected with S. enteritidis at a significantly greater frequency than the unmedicated controls. A significant decrease in cecal volatile fatty acid concentration, previously shown to influence susceptibility to selected enteric pathogens, was observed in the novobiocin- and nitrofurazone-treated groups. Treatment with chlortetracycline (11.4 g/kg), monensin (0.91 g/kg), or nicarbazin (0.49 g/kg) had no effect on S. enteritidis invasion or colonization. Bacitracin (0.49 g/kg) significantly increased S. enteritidis cecal colonization rate when administered continuously throughout the study. These data support and extend previous investigations involving other salmonellae and indicate that selected antibiotics may increase the severity and frequency of S. enteritidis colonization and invasion rate in leghorn chicks.
将1日龄的来航鸡雏置于先前使用过的家禽垫料上的地面围栏中（可能接触正常鸡肠道菌群）7天，并提供含有几种抗生素或抗球虫药之一的饲料。在第7天，所有组均口服接种一株对杆菌肽、新生霉素、萘啶酸和呋喃西林耐药的肠炎沙门氏菌（10⁶ 菌落形成单位）。所有雏鸡在第13天处死，并对肝脏、脾脏和盲肠扁桃体进行培养。与未用药的对照组相比，日粮中添加新生霉素（0.385 g/kg）导致雏鸡阳性定植率（肝脏和脾脏或盲肠扁桃体）显著增加（P < 0.05）。同样，日粮中添加呋喃西林（0.3 g/kg）的雏鸡感染肠炎沙门氏菌的频率明显高于未用药的对照组。在新生霉素和呋喃西林处理组中，观察到盲肠挥发性脂肪酸浓度显著降低，先前已证明该浓度会影响对特定肠道病原体的易感性。用金霉素（11.4 g/kg）、莫能菌素（0.91 g/kg）或尼卡巴嗪（0.49 g/kg）处理对肠炎沙门氏菌的侵袭或定植没有影响。在整个研究过程中持续给予杆菌肽（0.49 g/kg）可显著提高肠炎沙门氏菌在盲肠的定植率。这些数据支持并扩展了先前涉及其他沙门氏菌的研究，并表明某些抗生素可能会增加来航鸡雏中肠炎沙门氏菌定植的严重程度和频率以及侵袭率。
