Development of a model to study Aspergillus fumigatus proliferation on the air cell membrane of in ovo injected broiler eggs.
A model was developed to examine the proliferation of Aspergillus fumigatus on the air cell membrane of broiler hatching eggs and to assay the effectiveness of fungal control strategies that may be used in conjunction with late embryonic egg injection. Egg yolk was identified as the nutritive media required to sustain fungal growth. Incubation was required to predispose the egg to fungal infection by allowing the yolk to come into contact with the air cell membrane. Infertile eggs and eggs containing embryos that died before 4 d of incubation (early-dead) that had been subsequently incubated for 9 d or more were equally susceptible to fungal infection. In order to evaluate potential methods of control, these eggs were punched through the blunt end of the shell with a 16-gauge needle, placed into forced-air incubators (hatchers), and exposed to air-dispersed pure cultures of A. fumigatus. The frequency of eggs exhibiting mold growth on the air cell membrane 72 h after exposure was subjected to a Chi-square analysis model. The effect of egg position within an incubator flat in relationship to the A. fumigatus source culture, the variation between flats (levels) within a given hatcher, the variation between hatchers, and the variation between replicate trials were measured and found to be potential sources of experimental error that must be minimized in order to accept the results of an evaluation. A statistically valid model was developed that can be used to evaluate various types of fungicidal treatments of hatching eggs and their relative efficacy in association with egg injection.
Williams
C J
CJ
Department of Poultry Science, North Carolina State University, Raleigh 27695-7608, USA.
Murray
D L
DL
Brake
J
J
D000818:Animals; D001232:Aspergillus fumigatus / Q000254:growth & development*; D002642:Chick Embryo / Q000382:microbiology*; D004528:Egg Shell; D004530:Egg Yolk / Q000382:microbiology; D020964:Embryo Loss; D006863:Hydrogen-Ion Concentration; D009024:Morphogenesis