Genetic resistance to mortality of day-old chicks and carrier-state of hens after inoculation with Salmonella enteritidis

The heritability of resistance of poultry to Salmonella enteritidis (SE) was investigated. Three measurements of resistance were made: survival after intramuscular inoculation of 419 day-old chicks, absence versus presence of Salmonella in spleens and caeca 4 weeks after oral inoculation of 304 hens at peak of laying, and antibody response of 228 hens following two inoculations of an aroA mutant of this serotype, In the first two models of infection, resistance appeared to be heritable. The heritability was estimated from the sire and dam components, respectively, at 0.14+/-0.10 and 0.62+/-0.16 for chick mortality, 0.47+/-0.21 and 0.13+/-0.26 for resistance to spleen contamination, and 0.24+/-0.15 and 0.53+/-0.26 for resistance to caecal contamination in laying hens. By contrast the estimated heritability of antibody response was very low (0.03+/-0.08 and 0.10+/-0.08 when estimated from the sire and dam components, respectively). These results suggest that a selection for increased resistance to SE may be efficient.