【摘要】 为了筛选盐酸恩诺沙星颗粒治疗自然感染细菌性猪呼吸道疾病（SRD）的合理有效剂量，本试验通过临床诊断、病理剖检和细菌分离筛选150头自然感染细菌性SRD的杜长大三元杂交猪，随机分为5个组，即高剂量（HDG）组、中剂量（MDG）组、低剂量（LDG）组、药物对照（TFP）组和感染对照（ICG）组，HDG、MDG和LDG组试验猪分别口服给予10.0、7.5和5.0 mg/（kg·bw）包被的盐酸恩诺沙星颗粒，拌料给药1次，对于严重或慢性SRD病例，48 h后补充给药1次；TFP组给予延胡索酸泰妙菌素预混剂，87.5 g/1 000 kg饲料混饲，连续给药10 d;ICG组不给予任何药物。试验期间（0～24 d）每日观测各组试验猪的体重和临床症状；试验前（0 d）和试验后（24 d）检测体重，并采集鼻拭子进行细菌分离和鉴定；试验期间对病死猪进行剖检和病理学检查；分析试验后各给药组的治愈率。结果显示，所筛选的试验猪均有食欲不振、咳嗽、消瘦和体温升高等症状；与ICG组相比，各给药组试验猪体重均显著增加（P<0.05），体温均显著减低（P<0.05）；试验前各组试验猪鼻拭子均分离到了1种或多种SRD相关病原菌，包括胸膜肺炎放线杆菌、多杀性巴氏杆菌、猪链球菌和副猪格拉瑟菌等，且细菌分离率基本一致；试验后，除TFP组多杀性巴氏杆菌检出率无显著差异（P > 0.05），其余给药组猪鼻拭子中的各病原菌检出率均显著降低（P<0.05）；试验期间HDG和LDG组各死亡2头，ICG组死亡4头，MDG和TFP组无死亡，病死猪剖解后表现为严重肺炎，肺间质水肿、出血，炎性细胞浸润，肺泡代偿性扩张明显；HDG、MDG和LDG组治愈率分别为86.7%、83.3%和60.0%,TFP组为86.7%。结果表明，包被的盐酸恩诺沙星颗粒以7.5 mg/（kg·bw）剂量拌料给药，严重或慢性呼吸道疾病猪48 h后补充给药1次，对治疗自然感染细菌性SRD效果最佳。因此，包被的盐酸恩诺沙星颗粒以7.5 mg/（kg·bw）剂量作为临床推荐剂量使用，能有效治疗由细菌引起的SRD、减轻疾病造成的损失、降低死亡率和节省人力物力。更多还原

【Abstract】 To determine the optimal and effective dosage of enrofloxacin hydrochloride granules for the treatment of naturally occurring bacterial swine respiratory disease(SRD), 150 Du Changda Sanyuan hybrid pigs naturally infected with bacterial SRD were selected through clinical diagnosis, pathological necropsy, and bacterial isolation. The pigs were randomly divided into five groups: High-dose group( HDG), Medium-dose group( MDG), Low-dose group( LDG), Therapeutic control group( TFP), and Infection control group( ICG). The HDG, MDG, and LDG pigs were orally administered coated enrofloxacin hydrochloride granules at 10. 0, 7. 5, and 5. 0 mg（/kg·bw）, respectively, mixed into feed once; for severe or chronic SRD cases, a second dose was given after 48 h. The TFP group received tiamulin fumarate premix at 87. 5 g/1 000 kg feed for 10 consecutive days, while the ICG group received no medication. During the trial( day 0-24), daily monitoring of body weight and clinical signs was performed. On day 0 and day 24, body weight was recorded, and nasal swabs were collected for bacterial isolation and identification. Dead pigs during the trial were subjected to necropsy and histopathological examination. Cure rates for each treatment group were calculated after the trial. The results showed that all selected pigs exhibited symptoms such as anorexia, coughing, emaciation, and fever. Compared with the ICG group, pigs in all medicated groups had significantly increased body weight( P < 0. 05) and significantly reduced body temperature( P < 0. 05). Before treatment, nasal swabs from all groups yielded one or more SRD-associated pathogens, including Actinobacillus pleuropneumoniae, Pasteurella multocida, Streptococcus suis, and Glaesserella parasuis, with similar bacterial isolation rates among groups. After treatment, pathogen detection rates in nasal swabs were significantly reduced in all medicated groups( P < 0. 05), except for P. multocida in the TFP group( P > 0. 05). During the trial, two pigs died in the HDG and LDG groups, and four died in the ICG group, while no deaths occurred in the MDG or TFP groups. Necropsy of dead pigs revealed severe pneumonia, pulmonary interstitial edema and hemorrhage, inflammatory cell infiltration, and obvious compensatory alveolar expansion. Cure rates were 86. 7%, 83. 3%, and 60. 0% for the HDG, MDG, and LDG groups, respectively, and 86. 7% for the TFP group. In conclusion, coated enrofloxacin hydrochloride granules administered at 7. 5 mg（/kg·bw） mixed into feed, with a second dose after 48 h for severe or chronic respiratory disease cases, achieved the best therapeutic effect against naturally occurring bacterial SRD. Therefore, a dosage of 7. 5 mg（/kg·bw） is recommended for clinical use, as it effectively treats bacterial SRD, reduces losses caused by the disease, lowers mortality, and saves labor and resources.更多还原