Assessment of reproductive function in southern African spiny mice (<i>Acomys spinosissimus</i>) using faeces as hormone matrix

Abstract

For spiny mice, detailed long-term data on reproductive endocrine function is lacking, as limited blood volumes make frequent collections of individual plasma samples for hormone monitoring impractical. To provide the necessary tools in order to fill this gap, this study examined the suitability of two enzyme immunoassays for monitoring male and female reproductive function in the southern African spiny mouse (Acomys spinosissimus) based on faecal hormone analysis. Fourteen non-pregnant and one pregnant female and 24 male spiny mice were wild-caught and subsequently monitored under controlled conditions. Thirteen of the 14 non-pregnant females revealed elevated faecal progestagen metabolite concentrations with eight individuals showing indications of a luteal phase. Two females showed two post-ovulatory luteal phases with estimated cycle lengths of 16 and 18 days, respectively. The pregnant female had an elevated (231%) mean faecal progestagen metabolite level compared with the overall mean baseline hormone concentration determined for the 14 non-pregnant females. Males exposed to a long photoperiod, simulating summer-related breeding activity, exhibited a 47.8% increase in faecal androgen metabolite levels compared with males exposed to a short photoperiod. Collectively, the data demonstrated that reproductive endocrine function can be monitored in male and female spiny mice by measuring respective faecal hormone metabolites.

Key words: Acomys spinosissimus, southern African spiny mouse, progestagens, androgens, non-invasive hormone monitoring.