Assisted Reproduction in Wild Animals: Advances for the Conservation of Brazilian Species
At the beginning of the XXI century, we will be able to have lost a million of more species of plants, animals and other organisms (Corson, 1996). Some of these processes of extinguishing are natural, decurrent of the proper evolution of the species. However, the main causes of the loss of the biological diversity currently are the destruction of the habitat, the introduction of exotic species and the direct hunt. The conservation of the species is intrinsically linked to the maintenance of the genetic variability. When a population is geographically isolated and is subjects to the genetic uniformity, some factors unite to unchain the extinguishing process. Between these factors are the biggest susceptibility to diseases, the increase of spermatic abnormalities, the reduction of the fertility, the endocrine reproductive hormone unbalance affecting the spermatogenesis, the ovulation and the perinatal morbidity and mortality (Wildt et al., 1987; Munson et al., 1996; Brien & Mccullogh, 1985; Eizirik et al., 2001).
Strategies of conservation objectify to keep and, if possible, to increase the biodiversity. The ideal action to reach this objective is to preserve the habitat of the species (Loi et al., 2001). However, conservation strategies in situ nor always are enough in the propagation of small populations and the maintenance of one adequate genetic variability (Comizzoli, et al., 2000). In this direction, strategies of ex situ conservation objectifies to help in the conservation of a viable population by means of strategies of assisted reproduction and cryopreservation of genetic sources (Andrabi & Maxwell, 2007). Technologies of assisted reproduction as artificial insemination, in vitro fertilization and embryo transfer become more applied each time (Swanson, 1998; Wildt & Roth, 1997). Beyond the inquiry of the reproductive potential of these animals, these technologies have as application the transport only of the genetic material isolated between free wildlife and captivity animal populations (Wildt & Roth, 1987; Swanson, 1998). They can allow the increase in the birth of offspring by selected parents of form to increase the diversity of the population and to reduce the interval between birth (Andrabi & Maxwell, 2007). The application of the artificial insemination also reduces the risks of transmission of infectious illnesses during copulation and the problems with physical injuries during copulation, in special in felids that are of course aggressive (Wildt, 1990).
By being on the top of alimentary chain the carnivores in general way are used as animal flag for conservation of the too much species. So, the projects of conservation, in special in situ, that involve these animals, has a range multiplied in sight of the necessary area for hunting and shelter. In this way there are more abundant study in assisted reproduction in felids that any another wild group. Also innumerable works are developed in domestic carnivores aiming at experimental models for application in those from the wild. Studies of animal reproduction range a diversity of areas that are interrelated, including gamete biology, embryology and endocrinology, however, the advances most significant for the attended reproduction come being observed in the cryobiology. On the other hand, the study and the preliminary propagation of the basic biological knowledge and for new technologies, are very requested, therefore there are great species-specific variations that need to be considered in the global development of protocols in assisted reproduction. Aspects as: more indicated anesthesias to each procedure, thermoresistance of gametes, electroejaculation protocols, spermatic pathologies, cooling and freezing taxes of gametes, induction of the ovarian activity, etc, are base for experimentations of in vitro fertilization, embryos transfer, etc. Thus, of all the works in literature, the spite of the great variability of species and complexity of the tried protocols, always add applicable knowledge. Ambitious projects become considered, in one of them intend it intergeneric embryos transfer.
The assisted reproduction of wild animals is in some ways a proposal controversial, a time that the ideal in conservative terms would be to indirectly act in the maintenance of the species, supplying areas with considerable abundance of foods and shelter, however, would be an utopia to wait a reversion of the negative trend of the human action in the environment. Another negative question would be the election and production of inapt animals to the natural reproduction, which had acquired na imprint of artificial behaviors and the lack of the natural election. In any way, supplying options has to be offered, and the artificial reproduction can be the only hope for some species of our Brazilian animals.
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