SALMONELLA-ENTERITIDIS IN EGGS, CLOACAL SWAB SPECIMENS, AND INTERNAL ORGANS OF EXPERIMENTALLY INFECTED WHITE LEGHORN CHICKENS

Objective-To investigate prevalence of Salmonella enteritidis-positive eggs, excretion of the organism in fecal droppings, and infection of internal organs after oral inoculation of White Leghorn hens with S en teritidis phage type 8. Animals-30 White Leghorn laying hens. Procedur e-At 25 weeks of age, hens were each inoculated orally with 10(10) col ony-forming units of S enteritidis, then were observed for 8 weeks. Re sults-Salmonella enteritidis Y-8P2 did not cause any clinical signs of disease or decrease in egg production. However, at 1 week after inocu lation, 63.9% of the eggs collected from inoculated hens were culture positive for S enteritidis. The organism was isolated from the shell w ashings, egg shells, yolk, and albumen. A total of 592 eggs from S ent eritidis-inoculated hens were examined. Of these eggs, 157 (26.5%) wer e positive for S enteritidis on external shell washings alone, 17 (2.9 %) were positive for S enteritidis internally, and 44 (7.4%) were posi tive for S enteritidis externally and internally. The percentage of cu lture-positive eggs gradually decreased between postinoculation weeks 2 and 5, then gradually increased to a high of 76% at week 8. At 3, 7, and 10 days after S enteritidis inoculation, cloacal swab specimens f rom 3 hens were positive for S enteritidis. Salmonella enteritidis was recovered from ovary, oviduct, liver, and cecal junction from S enter itidis-inoculated hens. Conclusions-Our results indicated that birds i nfected with this isolate produced S enteritidis-positive eggs at high frequencies initially, that decreased over time. When S enteritidis a ntibody began to decrease, reaching geometric mean titer less than or equal to 40, the frequency of S enteritidis-positive eggs increased.