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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.
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