Abstract
1. An experiment was designed to determine whether the inclusion of sodium selenite, Sel-Plex or Sel-plex + Bioplex in the diet exerted any influence on structural and functional properties of the eggshell at 22, 38, 58 and 72 weeks age.
2. Significant age effects were demonstrated for egg weight, dynamic stiffness and total shell thickness.
3. The eggshells from birds fed on the Sel-Plex + Bioplex treatment were statistically stronger than those produced by the birds on sodium selenite.
4. From mid-lay onwards the shells laid by birds fed on the Sel-Plex + Bioplex treatment displayed, at ultrastructural level, the crystal modification termed ‘confluence’ together with early fusion of the palisade columns which comprised the bulk of the shell.
5. At all periods of lay the shells of birds fed on sodium selenite, Sel-Plex and the control diet demonstrated the presence of a variety of crystalline aggregates localised between the forming palisade columns.
Acknowledgements
The authors thank Dr J.T. Pickard and Zoe Kay for co-ordinating this programme of work, Alltech® Inc. for funding the investigation and Karina McDade for her technical expertise.