Comparative Toxicology and Wildlife Health
Research on Non-human Primates
Feeding Competition and Reproductive Condition in Free-ranging Female White-faced Sakis in Venezuela (Susan Shideler, Marilyn Norconk).
This study is still in progress and involves the study of free-ranging monkeys in Venezuela in order to understand female interactions in small to medium sized groups. We are performing fecal steroid hormone analyses in samples obtained from free-ranging saki monkeys in South America. These studies are extensions of our earlier studies that validated these assays with captive sakis from Roger Williams Park Zoo. Like the tamarin studies, it was one of the first studies to use fecal steroid analyses to evaluate reproductive function in free-ranging individual animals. The following questions are being assessed: a) how do females in the same group differ in their ability to gain access and to ingest food items; b) do differences in feeding rates among females translate into differences in nutritional intake; and c) how do these two variables impact reproduction?
Research on Other Mammals
The Efficacy of Different Presentations of PZP as an Immunocontraceptive and/or Immunosterilant in black-tailed and fallow deer (Bill Lasley and Susan Shideler).
This study tests the efficacy of a single shot vaccine using different peptides. These results from a single treatment will be compared to those of the double shot approach. Ovarian tissues taken from animal subjects in this study will be analyzed for gross pathology and by immunohistochemistry to see what types of pZP are found in these tissues. It is anticipated that the data provided by these studies will help protect and preserve a unique and delicate habitat by facilitating progress toward utilizing immunocontraception /sterilization as a means of population control --a preferred management strategy that is not only consistent with management policies, guidelines, regulations, and public sentiment, but which will ensure the continued ecosystem health and viability in a closed system
Developing Immunosterilants for Wildlife Population Control (Bill Lasley).
While immunocontraception has been useful to slow the rate of growth in free-ranging populations, this approach is not effective in reducing or eliminating unwanted groups of animals. To address this problem we have developed and field-tested immunological methods for immunosterilization of non-domestic ungulates. Using native porcine zona pellucida (pZP) and synthetic peptides that combine both "B" and "T" cell epitopes, we have immunized captive deer and are in the process of evaluating changes in ovarian tissues that would indicate a sterilizing effect.
Research on Birds
Endocrine Disruption of Avian Species (Bill Lasley and Beckye Stanton).
Environmental hazards, particularly endocrine disruptors, have been reported to have had profound adverse effects on wildlife. Amphibians, fish and avian species have been observed to have developmental defects and reduced reproduction, and it is speculated that these are a result of exposure to persistent organochlorine pollutants (POPs). Despite these observations there is a lack of consensus regarding the role of POPs in wildlife toxicology. To address some of these questions we used the chicken as a laboratory model and subsequent studies will investigate non-domestic bird species using the same methods. The results have demonstrated that dioxin has many of the same adverse effect in chickens as we had previously observed in mammalian laboratory models. However, in sharp contrast to mammals, which exhibit an increased sensitivity of the male to dioxin, the chicken model revealed an increased sensitivity of the female. More importantly, we have identified specific adverse effects of dioxin in blocking the ability of estrogen to increase individual fatty acids. We therefore can propose that developmental defects that have previously been observed but not explained, may be the results of environmental toxicants, particularly POPs, acting in conjunction with estrogen to prevent the production of key fatty acids that are essential for neural development.