Virulence of three Canadian poultry strains of Salmonella enteritidis, namely phagetypes (PT) 4, 8 and 13, and one Salmonella heidelberg strain was assessed in orally and intraperitoneally inoculated one-day old chickens and compared to the virulence of a human S. enteritidis PT 4 strain from the United Kingdom (UK). The two PT 4 strains were also compared in orally inoculated adult laying hens. In addition, orally inoculated Balb/c mice were used to evaluate virulence of the above strains and two strains of Salmonella typhimurium containing different plasmids. In orally inoculated one-day old chickens, the UK S. enteritidis PT 4 strain was more virulent than the Canadian PT 4 strain. The UK PT 4 strain was also more virulent and invasive in adult laying hens than the Canadian PT 4 strain. The S. enteritidis PT 8 strain and one S. typhimurium strain isolated from a chicken hatchery were the most virulent for orally inoculated Balb/c mice. This strain of S. typhimurium contained the 60 megadalton plasmid associated with virulence for Balb/c mice which was not present in the S. typhimurium strain isolated from a pig with septicemic disease.

Immunoreactivity for 28 kd vitamin D-dependent calcium-binding protein (calbindin-D28k) has been localized in the germinal epithelium and cells surrounding oogonia and oocytes (future granulosa cells) of developing and growing ovaries of chicken embryos. The protein first appeared prominently in the germinal epithelium of the developing left ovary in 8-day embryos. At the twelfth day of incubation, cells surrounding oogonia and oocytes reacted intensely for calbindin-D28k. The number and intensity of calbindin-D28k-containing cells increased in both types of cells as the embryos further developed. Calbindin-D28k remained in the germinal epithelium throughout the study period observed (up to 10 weeks). However, the protein was present transiently in the future granulosa cells. It gradually decreased after hatching, and was virtually absent from granulosa cells in a 10-week old chicken. Compared with the known process of onset of sexual development, these results indicated possible involvement of calbindin-D28k in the early phases of oogenesis in chicken ovaries.