PROJECT SUMMARY/ABSTRACT
The goal is to establish a state-of-the-art vivarium, which will be dedicated exclusively to the UTRGV Laboratory
Opossum (Monodelphis domestica) Research Resource, and which will provide expanded opportunities for
biomedical research with this unique laboratory animal to investigators and students at UTRGV and other
institutions. This resource is the only large research colony of any marsupial species, and it contains the only
genetic stocks and inbred strains that have been developed for any marsupial species. The resource is widely
shared with investigators from other institutions, and it serves as the only readily accessible source of research
animals, breeding nuclei, and biological materials from this species, and of opportunities for investigators from
other institutions to conduct hands-on (or remote) research with this species without establishing their own
colonies. State funds were secured for construction of the building that will contain the new vivarium, and the
building will be ready for occupancy early in 2024. Use of the funds was restricted to the building and fixed
equipment; the funds could not be used for caging. To fill the gap in funding, the single specific aim of this
proposal is to purchase and install ten racks of a state-of-the-art IVC system. Sixteen racks currently in
use are available to be moved to the new vivarium. The complete caging system will include 13 Optimice racks
(1,300 cages) for individually housed opossums and 13 Optirat racks (546 cages) for mated pairs, mothers with
litters, and groups of littermates. Six racks of each type will be installed in each of two breeding/holding rooms;
and one rack of each type will be installed in a smaller room for research with infectious agents or for quarantine
purposes. The breeding/holding rooms will house the 20 genetic stocks and inbred strains that comprise the
breeding colony, as well as animals used in research that does not involve infectious agents. The current
opossum resource has a steady state of 1,200 animals, which are housed in an overcrowded vivarium with many
deficiencies. The new vivarium and caging system will enable the steady state of the colony to increase to 1,726
animals, which will be maintained under optimal conditions for animal welfare and for financial and operational
efficiency. That number of animals will be sufficient in the intermediate-term future for maintaining the 20
breeding groups and providing sufficient animals and research capacity to meet the national need. The IVCs will
provide maximal protection from the transmission of infectious diseases, high air quality for the animals, and
minimal exposure of staff to allergens that emanate from the animals. Moreover, the selected caging system is
the ultimate in green technology design; it depends on filtered room exhaust air being pulled through the cages
and out of the building by the HVAC system, rather than on motors and blowers. The overarching outcome
will be to establish an efficient, high-quality, high-capacity laboratory opossum research resource that
is capable of meeting current demand for laboratory opossums for biomedical research, and of fulfilling
the increasing institutional and national need for this species well into the future.