Gaunt Patricia S, Endris Richard, McGinnis Anissa, Baumgartner Wes, Camus Alvin, Steadman James, Sweeney Diane, Sun Fangshi
Thad Cochran National Warmwater Aquaculture Center, College of Veterinary Medicine, Mississippi State University, 127 Experiment Station Road, Stoneville, Mississippi 38776, USA.
J Aquat Anim Health. 2010 Sep;22(3):158-66. doi: 10.1577/H09-044.1.
A dose titration study was conducted to determine the dosage of florfenicol (FFC) in feed to control Streptococcus iniae-associated mortality in Nile tilapia Oreochromis niloticus. Six tanks were assigned to each of five treatments: (1) not challenged with S. iniae and fed unmedicated feed; (2) challenged with S. iniae by injection and fed unmedicated feed; (3) challenged with S. iniae and given FFC at 5 mg/kg of body weight (bw) in medicated feed; (4) challenged with S. iniae and given 10 mg FFC/kg bw; and (5) challenged with S. iniae and given 15 mg FFC/kg bw. Treatment was initiated the day after inoculation, and feed was administered for 10 d. Cumulative mortality was 0% in the unchallenged, untreated group; 35.8 +/- 4.4% (mean +/- SE) in the challenged, unmedicated group; 19.2 +/- 2.7% in the 5-mg/kg treated group, 12.5 +/- 3.8% in the 10-mg/kg group, and 2.5 +/- 1.1% in the 15-mg/kg group. The cumulative mortality was significantly less in each challenged, FFC-treated group than in the challenged, unmedicated controls (5 mg/ kg: P = 0.0156; 10 mg/kg: P = 0.0007; 15 mg/kg: P < 0.0001). The efficacy of the 10- and 15-mg/kg FFC dosages was studied in a separate dose confirmation study. Fish in all tanks were injected with S. iniae. At 4 h postinoculation, 10 tanks were assigned to each of three feed treatments: (1) unmedicated feed; (2) 10 mg FFC/kg bw; and (3) 15 mg FFC/kg bw. Cumulative mortality was 20.5 +/- 2.0% in the challenged, unmedicated group; 11.0 +/- 2.1% in the 10-mg/kg group; and 5.5 +/- 2.4% in the 15-mg/kg group. Mortality was significantly less in the medicated groups than in the challenged, unmedicated control group (10 mg/kg: P = 0.0270; 15 mg/kg: P = 0.0007). Fish in both studies were necropsied, cultured for bacteria, and examined for gross lesions. The minimum inhibitory concentration of FFC against S. iniae in both studies ranged from 0.5 to 1.0 microg/mL. Florfenicol was palatable, safe, and efficacious for control of Nile tilapia mortality due to S. iniae infection.
进行了一项剂量滴定研究，以确定饲料中氟苯尼考（FFC）的剂量，用于控制尼罗罗非鱼奥利亚罗非鱼中与海豚链球菌相关的死亡率。将六个水箱分配给五种处理中的每一种：（1）不接种海豚链球菌并投喂未加药的饲料；（2）通过注射接种海豚链球菌并投喂未加药的饲料；（3）接种海豚链球菌并在加药饲料中给予5毫克/千克体重（bw）的FFC；（4）接种海豚链球菌并给予10毫克FFC/千克bw；（5）接种海豚链球菌并给予15毫克FFC/千克bw。接种后第二天开始处理，并投喂饲料10天。未接种、未处理组的累积死亡率为0%；接种、未加药组为35.8±4.4%（平均值±标准误）；5毫克/千克处理组为19.2±2.7%，10毫克/千克组为12.5±3.8%，15毫克/千克组为2.5±1.1%。每个接种、FFC处理组的累积死亡率均显著低于接种、未加药对照组（5毫克/千克：P = 0.0156；10毫克/千克：P = 0.0007；15毫克/千克：P < 0.0001）。在一项单独的剂量确认研究中研究了10毫克/千克和15毫克/千克FFC剂量的疗效。所有水箱中的鱼均接种海豚链球菌。接种后4小时，将10个水箱分配给三种饲料处理中的每一种：（1）未加药的饲料；（2）10毫克FFC/千克bw；（3）15毫克FFC/千克bw。接种、未加药组的累积死亡率为20.5±2.0%；10毫克/千克组为11.0±2.1%；15毫克/千克组为5.5±2.4%。用药组的死亡率显著低于接种、未加药对照组（10毫克/千克：P = 0.0270；15毫克/千克：P = 0.0007）。两项研究中的鱼均进行了尸检、细菌培养并检查了大体病变。两项研究中FFC对海豚链球菌的最低抑菌浓度范围为0.5至1.0微克/毫升。氟苯尼考对于控制尼罗罗非鱼因海豚链球菌感染引起的死亡率而言适口性好、安全且有效。
