Bacterial numbers from landlocked fall Chinook salmon eyed eggs subjected to various formalin treatments as determined by scanning electron microscopy and bacteriological culture methods
Bacterial numbers from landlocked fall Chinook salmon eyed eggs subjected to various formalin treatments as determined by scanning electron microscopy and bacteriological culture methods
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DOI：
10.1577/fa04-019.1
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发表时间：
2005-01-01
影响因子：
1
通讯作者：
Cordes, RJ
中科院分区：
文献类型：
--
作者：
Barnes, ME;Bergmann, D;Cordes, RJ
本研究比较了两种方法的计数细菌粘附到外部膜的内陆秋季奇努克鲑鱼Oncorhynchus tshawytscha的鸡蛋进行不同的福尔马林处理方案，从鸡蛋的眼睛，鱼苗孵化。通过扫描电子显微镜（SEM）直接计数细菌或通过提供菌落形成单位数的既定细菌培养方法记录细菌数。治疗方案包括每天暴露于500 mg/L或1，667 mg/ L福尔马林15分钟或最初不暴露于福尔马林，然后在眼睛向上后7天开始暴露于1，667 mg/L剂量。对照组在整个实验过程中不接受任何福尔马林处理。平板培养法测定的每平方毫米卵膜菌落形成单位（CFUs）数与扫描电子显微镜计数的每平方毫米细菌数之间无显着相关性。用扫描电镜测定的细菌数比平板培养的细菌数高40-120倍。SEM数与胚胎存活率相关，但CFU数与胚胎存活率无关。对于两种计数方法，未处理对照组中的细菌数量随时间推移而增加。在培养物中鉴定的三种细菌（柱状黄杆菌，鞘氨醇杆菌属，和假单胞菌属），F.专栏占主导地位。在托盘中，没有收到任何福尔马林的胚胎存活率显着低于所有其他的治疗，但有任何三个福尔马林治疗方案之间的生存没有显着差异。
This study compared two methods of enumerating bacteria adhered to the external membrane of eggs of landlocked fall Chinook salmon Oncorhynchus tshawytscha that were subjected to different formalin treatment regimes from egg eye-up to fry hatch. Bacterial numbers were recorded by either directly counting bacteria via a scanning electron microscope (SEM) or via established bacterial culture methods that provided the number of colony-forming units. Treatment regimes consisted of a daily 15-min exposure to formalin at either 500 mg/L or 1,667 mg/ L or no formalin initially followed by exposure to a 1,667-mg/L dose starting 7 d after eye-up. A control group did not receive any formalin treatments throughout the experiment. No significant correlation was observed between the number of colony-forming units (CFUs) per square millimeter of egg membrane determined by plate culture and the number of bacteria per square millimeter counted with the SEM. Bacterial numbers determined by the SEM were 40-120 times greater than those obtained by plate culture. The SEM numbers were correlated to embryo survival, but CFU numbers were not. For both counting methods, bacterial numbers among the untreated controls increased over time. Of the three species of bacteria identified in cultures (Flavobacterium columnare, Sphingobacterium spp., and Pseudomonas spp.), F. columnare was predominant. Embryo survival in the trays that did not receive any formalin was significantly less than that in all of the other treatments, but there was no significant difference in survival among any of the three formalin treatment regimes.