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Title: THE EFFECT OF KILLED SALMONELLA ENTERITIDIS VACCINE PRIOR TO INDUCED MOLTING ON THE SHEDDING OF S. ENTERITIDIS IN LAYING HENS

Author
item NAKAMURA, MASAYUKI - KITASATO UNIV, JAPAN
item NAGATA, TOMOSHI - KITASATO UNIV, JAPAN
item OKAMURA, SHIZUKA - KITASATO UNIV, JAPAN
item TAKEHARA, KAZUAKI - KITASATO UNIV, JAPAN
item Holt, Peter

Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/11/2003
Publication Date: 1/15/2004
Citation: Nakamura, M., Nagata, T., Okamura, S., Takehara, K., Holt, P.S. 2004. The Effect Of Killed Salmonella Enteritidis Vaccine Prior To Induced Molting On The Shedding Of S. Enteritidis In Laying Hens. Avian Diseases 48:183-188.

Interpretive Summary: Induced molting is an extremely important procedure for the table egg industry to achieve a second egg lay from aging layer flocks. It is estimated that over 70% of layer flocks are molted annually in the U.S., affecting more than 160 million hens. However, it had been shown previously that this important industry tool could cause problems with Salmonella enterica serovar Enteritidis (SE) infections so methods were examined to reduce this problem. An earlier study showed that immunizing hens with a live Salmonella vaccine actively protected hens against SE infection during molt and the current study examined whether the use of a killed SE vaccine could provide similar protection. Excretion of SE in the feces was significantly reduced in vaccinated hens at 3 and 14 days after SE challenge thereby reducing the chance for the organism to spread to other hens within the flock or to rodents within the house and reduces the load of SE in the environment which must be dealt with during disinfection and clean up of the premises at flock termination. These results indicate that immunizing hens with a killed SE vaccine prior to molting can help reduce SE problems during a molt situation.

Technical Abstract: Effects of administering killed Salmonella enterica serovar Enteritidis (SE) vaccines to laying hens prior to induced molting on egg production and on shedding of SE were investigated. Sixty hens were vaccinated with Layermune or Inactivac SE4, commercially-available SE vaccines in USA and Japan. Four weeks after vaccination, hens were molted. Four days after molting, all hens were challenged with a dose of 2.4 billion SE. For 4 weeks after vaccination, egg production in vaccinated hens showed ca. 15% decrease. After molting, egg production in molted hens ceased and then returned to the normal level after 8 or 9 weeks of vaccination. For 3 months, there were not great differences between the numbers of eggs in the unvaccinated-molted group compared with the two vaccinated-molted groups. Hens in the vaccinated-molted groups shed about 2 logs less SE than hens of the unvaccinated-molted group 3-14 days post challenge (P<0.05 or 0.01). Minimal differences in SE shedding were observed between these groups at later sampling times. While certain negative aspects of using killed SE vaccine prior to molting can be encountered, the used of killed SE vaccine should be considered in situations where the possibility of SE contamination within a flock which might be closely associated with food-borne salmonellosis.