A human reproductive approach to the study of infertility in chimpanzees: An experience at Leon's Zoological Park, Mexico

Great apes are mammals close to humans in their genetic, behavioral, social and evolutionary characteristics and new genomic information is revolutionizing our understanding of evolution in primates. However, all these species are endangered. While there are many global programs to protect these species, the International Union for Conservation of Nature (IUCN) projects that in a near future the wild populations will decrease significantly. Nowadays, the relevance of captive populations of great apes is becoming critical for research and understanding of pathophysiology of diseases. In this report, the evaluation of infertility in a group of captive chimpanzees maintained at Leon’s Zoological Park using a human infertility protocol is described. Our results suggested that infertility in this group was due to low hormonal levels and sperm alterations in the male characterized by hormonal assessment and a sperm sample obtained by electroejaculation and cryopreserved using human protocols. In the females, it was demonstrated that it is possible to follow the follicular cycle using non-invasive methods based on morphological changes in genitalia, detection of blood in urine and measurement of hormones in saliva samples; concluding that fertility in females was normal. Also, we demonstrate that human artificial insemination procedures may be applied. Our human approach was successful in finding the infertility cause in this group of captive chimpanzees. In countries with limited resources, collaboration of zoos with human infertility clinics can be beneficial for research and management of reproductive aspects of great apes.