Submitted to: Revista Latino Americana de Microbiologa
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/20/2004
Publication Date: 6/20/2004
Citation: Rosario, C.C., Tellez, I.G., Lopez, C.C., Villaseca, F.M., Anderson, R.C., Eslava, C.C. 2004. Bacterial isolation rate from fertile eggs, hatching eggs, and neonatal broilers with yolk sac infection. Revista Latino Americana de Microbiologa. 46:12-16. Interpretive Summary: Bacterial infections in hatching eggs are a major cause of death in chicks after they hatch from the egg. In order to learn which bacteria are the major cause of infections in the egg, bacteria were recovered from samples of fertile and nonfertile eggs and of nesting material. Bacteria were also recovered from the liver and yolk sac of dead chicks. Of the five hundred and eighty eight colonies that were isolated and identified, most were found to be Escherichia coli. In broilers, the numbers of chicks in the eggs that were dead was highly related to there being an E.coli infection present in the egg. Fertile egg contamination at the breeder farm level was found not to be a big problem. Rather, results suggested that egg contamination occured at a later stage. Results from this research will help poultry producers reduce contaminatation of eggs by E. coli thereby reducing the number of chicks that die. Ultimately, this research will benefit the American consumer by helping to reduce the costs of producing poultry products for their comsumption.
Technical Abstract: Yolk sac infections (YSI) are a major cause of mortality of broilers during their first week post-hatching. The aim of the present study was to analyze 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 longer egg incubation intervals. In this study, in contrast to previous reports by others, egg contamination did not occur at the breeder farm. However, bacterial contamination causing YSI in vertically integrated operations can occur at a latter stage. Since YSI mortality was highly correlated with E. coli isolation, this may be the primary causitive organism responsible for this disease.