235CHARACTERIZATION OF FECAL TESTOSTERONE PROFILES IN VOLCANO RABBIT (Romerolagus diazi) KEPT IN CAPTIVITYThe Volcano rabitt (Romerolagus diazi) is an endemic species of Mexico, restricted to the central part of the Mexican transvolcanic belt and it is considered as a endangered species. Although they can mate all year long, reproductive activity is more intense during the summer and decrease during the winter. This study describes the pattern of fecal testosterone secretion of eleven volcano rabbits adult males kept in captivity at Chapultepec Zoo quantified by ELISA, during two periods; Fall – Winter (October to February) and Spring – Summer (march to july). The concentration of fecal testosterone of zacatuche during the evaluation period was 111.01 ± 27.31 ng/g of dry feces. With a higher secretion in the Fall – Winter period (P<0.05). It was observed that testosterone levels are variable throughout the year, but always measurable and greater than zero, so playback is not supressed and it does not show a defined reproductive stage. These findings are consistent with the values found in domestic rabbit’s blood. The findings of the present work are the first reported for the species and are a important approach to the understanding of their reproductive phisiology. Moreover, it was found that the use of non-invasive methods such as measuring fecal steroids, is a suitable technique for monitoring reproductive activity in the volcano rabbit.acordova@correo.xoc.uam.mxResearch562015Volcano rabbit,Reproduction, Sexual hormones,Fecal steroids,Testosterone,ELISA,Non-invasive tecniquesAlejandro Córdova-Izquierdo,Alberto Olascoaga Elizarraraz,José Antonio Sandoval Zárate,Abel. E. Villa-Mancera,Jaime Olivares Pérez,Pedro Sánchez Aparicio,Ma. De Lourdes Juárez Mosqueda,Juan E. Guerra LieraDepartamento de Producción Agrícola y Animal. Universidad Autónoma Metropolitana. Unidad Xochimilco. Calzada del Hueso No. 1100, Col. Villa Quietud, C.P. 04960. Del. Coyoacán. México, D.F., Gobierno del Distrito Federal. Secretaría del Medio Ambiente. Dirección General de Zoológicos y Vida Silvestre. Zoológico de Chapultepec “Alfonso L. Herrera”. Calle Chivatito s/n, 1ª. Sección del Bosque de Chapultepec, Col. San Miguel Chapultep,Universidad Nacional Autónoma de México. Facultad de Medicina Veterinaria y Zootecnia. Circuito Exterior s/n, Ciudad Universitaria, C.P. 04510, Del. Coyoacán. México, D.F., Facultad de Veterinaria. Benemérita Universidad Autónoma de Puebla, México.,Unidad Académica de Veterinaria. Universidad Autónoma de Guerrero, Ciudad Altamirano, Guerrero, México.,Faculad de Veterinaria. Universidad Autónoma del Estado de México, México.,Departamento de Morfología. FMVZ-UNAM.,Facultad de Agronomía. Universidad Autónoma de Sinaloa, México.