|Nisbet, David - Dave|
Submitted to: Southern Poultry Science Society Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 1/20/2003
Publication Date: N/A
Technical Abstract: Spent laying hens often are subjected to forced molt in order to prolong their laying status. One popular method of forced molt involves the removal of access to feed during periods of reduced light. A negative result of total feed withdrawal is increased susceptibility to colonization and infection by enteropathogens. An alternative method to molt induction by total feed withdrawal is to provide hens access to feed containing high levels of zinc, which limits calcium availability. In the current study, a 16S rDNA PCR-based technique, denaturing gradient gel electrophoresis (DGGE), was used to visualize changes in crop and cecal bacterial populations in spent laying hens resulting from total feed withdrawal and the provision in the feed of 10,000 mg/kg of zinc, administered as zinc acetate or zinc propionate. Providing hens with zinc from both sources resulted in crop bacterial DGGE patterns with greater similarity to control patterns than those patterns resulting from complete feed removal. Comparisons of cecal bacterial DGGE patterns indicated that hens provided with dietary zinc acetate or zinc propionate had similarity coefficients 80% or greater. However, DGGE patterns for the hens given dietary zinc shared less than 80% similarity coefficients with bacterial populations from hens given access to feed or subjected to total feed removal. Results from other experiments have shown that hens provided with dietary zinc acetate continue to be resistant to enteropathogen colonization. However, results from the current study indicated that providing hens with dietary zinc from either source resulted in crop and cecal bacterial populations very different from those found in normally fed hens or hens deprived of feed.