Meeting Abstract
Practices involving the experimental alteration of hormone concentrations have been widely used to study how hormones influence behavior and physiology. In birds, silastic implants are the most commonly used method of elevating circulating hormones over a long-term period. However, silastic implants have a series of drawbacks; the amount of hormone that the implant releases into the body can be inconsistent, the implantation method requires minor surgery and stitches to keep the implant in place, and the implants need to be removed from the animal when the study ends. Previous studies in quail and others suggest that made of beeswax offer a less-invasive option, as the hormone concentrations are more precise, and the implant itself melts within the body, eliminating the need to retrieve the implant at the end of a study, however these have not been tested widely in other systems or with other hormones. In this study, we aimed compared hormone concentrations in laying hens after implanting them with testosterone propionate in either beeswax or silastic implants. For the beeswax implants, we generated beeswax pellets containing 1mg, 5mg, or 10mg of testosterone propionate. For silastic implants, we filled 1/4, 1/2, or 1-inch lengths of tubing (.095 nm inner diameter) with testosterone propionate. All implants were inserted subcutaneously in the neck region of the birds. We took blood samples prior to inserting the implants and every 3d after for two weeks, and then measured testosterone concentrations via ELISA. We also recorded egg-laying patterns and overall reproductive conditions of the hens. Overall, this study yields new information on whether beeswax implants represent a more efficient alternative for experimentally elevating hormones.
