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发表于 2021-11-5 10:49:22
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来自: 中国山东济南
常老师你好,我觉得你这样设计实验的话,实验结果很难说明问题。
要想分析受精蛋可能的污染问题(或者是造成死胚和弱雏的原因),需要对受精蛋和未受精蛋同时进行孵化处理,在19-21天内进行采样分菌,另外也要对鸡舍污染物(如粪便)、死胚、孵化出来1-7内死亡雏鸡的肝脏和卵黄囊进行采样分菌。最后进行详细的排查分析,才有可能确定主要污染源和关键污染菌。
根据国外的报道显示,种蛋的污染主要是在孵化过程中大肠杆菌的污染,而种鸡场对种蛋的污染很小。但是,到目前为止国内相关的报道不多,且实验设计不够合理。因此,国内种蛋污染或许与二者都有关系,但需要进一步的研究。
Cortés CR, Téllez Isaías G, López Cuello C, Villaseca-Flores JM, Anderson RC, Eslava Campos C. Bacterial isolation rate from fertile eggs, hatching eggs, and neonatal broilers with yolk sac infection. Rev Latinoam Microbiol. 2004;46(1-2):12-16.
文章摘要
Yolk sac infection (YSI) is a major cause of mortality of broilers during the first week post-hatching. The aim of the present-study was to analyze the possible sources of fertile egg contamination and to establish the etiology of YSI. Sixty fertile eggs, sixty sawdust samples from the nest, sixty nonfertile 19 to 21 day old incubation eggs and liver and yolk sac samples from 216 dead, 1 to 7 day old chicks, were cultured. Five hundred and eighty eight colonies were isolated and further characterized using biochemical tests. Escherichia coli was the most common bacterium recovered from all samples except the sawdust and fertile eggs collected from the nest. Fertile egg contamination at breeder farm level was found to be minimal. In broilers, both mortality and the rate of E. coli isolation were increased with the time. These results suggest that egg contamination does not occur at the breeders farm, as previously has been reported. Bacterial contamination causing YSI in vertically integrated operations can occur at a latter stage. It can be considered that the main etiologic agent of YSI is E. coli, since YSI mortality was highly correlated with E. coli isolation. |
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