|Lowry, Virginia - TEXAS A&M UNIVERSITY|
|Bowden, Lacy - TEXAS A&M UNIVERSITY|
|Genovese, Kenneth - TEXAS A&M UNIVERSITY|
Submitted to: Comparative Immunology Microbiology and Infectious Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 2, 1997
Publication Date: N/A
Interpretive Summary: Over the past 10 years, many studies have shown a large percentage of poultry products are contaminated with salmonellae. The objective of this experiment was to determine the role of a specific white blood cell (heterophil) and it's ability to engulf and kill Salmonella enteritidis in baby turkeys. It is believed that baby turkeys are very susceptible to salmonellae infections during the first 7 days after they hatch, because their white blood cells cannot efficiently engulf and kill the invading bacteria. We isolated a particular white blood cell, the heterophils, and incubated these in a test tube with salmonellae. The results from these experiments showed the heterophils from baby turkeys do not engulf and kill the salmonellae until the birds are 7 days old. This information is useful to the poultry industry because we have shown that a mature natural immune system in the baby turkey is vital for the resistance to salmonellae.
Technical Abstract: Turkey poults are extremely susceptible to Salmonella enteritidis (SE) during the first 7 days after hatch. Previous studies from our laboratory have shown heterophils isolated from turkeys 2 to 3 weeks of age efficiently phagocytize and kill SE. However, no studies have evaluated the functional activity of heterophils from young birds as a means of describing the association between innate immunity and susceptibility to early salmonellae infections. The objective of our study was to evaluate the proficiency of heterophils from turkey poults during the first 7 days of life to phagocytize and kill SE. Our results show heterophil phagocytosis increased significantly with age (day 1 - 37%, day 4 - 51%, and day 7 - 84%). Heterophils from 1-day-old and 4-day-old poults killed only 28 and 38% SE, respectively; whereas, heterophils from 7 day-old poults killed 71% SE, in vitro. These results strongly suggest phagocytosis and killing of SE by heterophils from turkey poults are age dependent events. Based on these results we conclude 1-to-4 day-old poults are more susceptible to SE infection, potentially due to the immature functional activity of the heterophil.