EGGS AND CHICKEN EMBRYOS AS POTENTIAL FLOCK AND HATCHERY HEALTH SENTINELS

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Eggs and chicken embryos as potential sentinels for flock and hatchery health

Publication . Noiva, Rute Marina Garcia da; Peleteiro, Maria da Conceição da Cunha e Vasconcelos; Shivaprasad, Hulimangala L.

Successful hatching of strong, healthy chicks with a potential for good productive and reproductive performance depends on the assurance of as normal and ideal as possible embryonic development. The latter, however, can be negatively affected by a series of factors intrinsic to either the egg, its handling, or the incubator. This project aimed at collecting and interpreting essential and extensive information regarding embryonal response to physical challenges (temperature, relative humidity and carbon dioxide concentration) in the incubation environment, to infectious challenge with vertically transmitted Salmonella serovars Enteritidis and Typhimurium and, ultimately, to apply the knowledge obtained to a field survey of a commercial hatchery. For this purpose, eggs were incubated under different, controlled environments or after infection with a vertically transmitted pathogen, and an extensive list of parameters used to monitor subsequent changes in embryonic behavior, metabolism, growth and viability. The information gathered was then applied to a sample of non-viable eggs incubated at a major hatchery. Overall, the effects of manipulating temperature were more prominent than those of manipulating humidity and carbon dioxide. The most significantly affected parameters pertained to embryo metabolism, embryo weight, mortality and malformation rates. Changes in the development of the lymphoid follicles in the bursa of Fabricius and of the glandular epithelium of the gizzard were also found. Vertical infection with Salmonella was associated with higher embryonic mortality rates. No changes in performance or growth were observed in infected but viable embryos. The results obtained during the field survey did not directly correlate to the variables studied. However, the issues detected allowed for the designation of critical control points and opportunities for performance improvement that could have otherwise gone undetected at the hatchery and at the breeder farm, highlighting the importance of embryodiagnosis in the monitoring of hatchery and flock health.

2016-04Tese de doutoramento

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Fundação para a Ciência e a Tecnologia

Número da atribuição

SFRH/BD/76371/2011