Forced molting of laying hens increases enteric foodborne pathogens in the reproductive
tract, leading to contaminated eggs and progeny of infected hens. Currently, we lack a complete
understanding of how conditions such as molting affect the immune system. Previous reports
have shown that alfalfa is effective in inducing a molt as well as in producing protection against
Salmonella Enteritidis organ invasion. Our laboratory has also shown that immune functions
are significantly reduced during molting. The present investigation evaluates a specific parameter
of immune function, heterophil function, during an induced molt in hens fed alfalfa.
Three replicate experiments used hens older than 65 wk of age that were divided into 6 groups
of 12 hens each and placed in individual laying cages. Two weeks before dietary changes,
hens were placed on an 8L:16D photoperiod that continued for the 12-d experiment. Peripheral
blood samples were taken from hens on d 0, 2, 6, and 12 of molt. Hens were randomly
placed into 3 treatment groups: nonfed hens, fully fed hens, and alfalfa-fed hens. To evaluate
heterophil functions, the production of an oxidative burst as well as cellular degranulation assays
were performed. In addition, total and differential peripheral blood leukocyte counts were
performed. When compared with the nonfed control, alfalfa-fed birds showed significantly (P
< 0.05) higher oxidative burst and degranulation activities. The data confirm previous observations
that heterophil functions are significantly decreased in nonfed birds and the data show
that birds fed alfalfa had numerically increased heterophil functions over a 12-d molting period
when compared with heterophils of nonfed controls. Commercial integrators should consider
using alfalfa when developing new molting programs.
Forced molting of laying hens increases enteric foodborne pathogens in the reproductivetract, leading to contaminated eggs and progeny of infected hens. Currently, we lack a completeunderstanding of how conditions such as molting affect the immune system. Previous reportshave shown that alfalfa is effective in inducing a molt as well as in producing protection againstSalmonella Enteritidis organ invasion. Our laboratory has also shown that immune functionsare significantly reduced during molting. The present investigation evaluates a specific parameterof immune function, heterophil function, during an induced molt in hens fed alfalfa.Three replicate experiments used hens older than 65 wk of age that were divided into 6 groupsof 12 hens each and placed in individual laying cages. Two weeks before dietary changes,hens were placed on an 8L:16D photoperiod that continued for the 12-d experiment. Peripheralblood samples were taken from hens on d 0, 2, 6, and 12 of molt. Hens were randomlyplaced into 3 treatment groups: nonfed hens, fully fed hens, and alfalfa-fed hens. To evaluateheterophil functions, the production of an oxidative burst as well as cellular degranulation assayswere performed. In addition, total and differential peripheral blood leukocyte counts wereperformed. When compared with the nonfed control, alfalfa-fed birds showed significantly (P< 0.05) higher oxidative burst and degranulation activities. The data confirm previous observationsthat heterophil functions are significantly decreased in nonfed birds and the data showthat birds fed alfalfa had numerically increased heterophil functions over a 12-d molting periodwhen compared with heterophils of nonfed controls. Commercial integrators should considerusing alfalfa when developing new molting programs.
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