RESUMEN
Coccidiosis causes dramatic economic losses in the poultry industry. Next to the extensive use of anticoccidial drugs, improving genetic resistance of birds to this parasitic disease represents an attractive alternative. An experiment was run in order to identify lines of chickens resistant and susceptible to coccidiosis as a tool to search for genetic markers of resistance. Five outbred lines were used: two Egyptian lines (Mandarah and Fayoumi), a Rhode Island Red line, and two White Leghorn lines (WLB21 and WLDW). The WLDW line segregated for three MHC haplotypes, B15, B19, and B21, and for the sex-linked dwarf gene, DW. Chicks were challenged at 4 wk of age with a high dose of Eimeria tenella (150,000 oocysts) and slaughtered 8 d postinoculation. Innate resistance was assessed individually by measures of lesion score, mortality, and body weight gain at slaughter, and plasma coloration 4 d postinoculation. Large differences in resistance to E. tenella were observed between lines. The Fayoumi line appeared clearly as the most resistant line, showing no mortality, less severe lesions than other lines, and a 30% reduction of growth as compared to control birds. The WLDW line was the most susceptible, with 27% mortality and a 85% reduction in growth. No major effect of MHC or dwarfism on resistance to E. tenella was found.
Asunto(s)
Pollos/parasitología , Coccidiosis/veterinaria , Eimeria tenella/inmunología , Enfermedades de las Aves de Corral/inmunología , Animales , Peso Corporal/fisiología , Pollos/genética , Pollos/inmunología , Coccidiosis/genética , Coccidiosis/inmunología , Enanismo/genética , Enanismo/veterinaria , Femenino , Ligamiento Genético , Genotipo , Inmunidad Innata , Complejo Mayor de Histocompatibilidad/genética , Masculino , Fenotipo , Enfermedades de las Aves de Corral/genéticaRESUMEN
Contamination of a hatchery by Aspergillus fumigatus has been studied for 8 weeks from eggs to day old chicks. We have shown that the contamination of the hatchery originates on the egg shell and that each time the eggs are manipulated, spores of Aspergillus fumigatus are thrown into suspension in the air. Thus it seems necessary to bring eggs with as few as possible spores of Aspergillus fumigatus on their shell into the hatchery. Prophylaxis of aspergillosis should be foreseen from the conception of the hatchery: the ventilation system and the internal lay-out should be designed to prevent dispersion and accumulation of Aspergillus fumigatus spores during the processing of the eggs through the hatchery.