Poster Presentation Annual Meetings of the Endocrine Society of Australia and Society for Reproductive Biology and Australia and New Zealand Bone and Mineral Society 2016

Development of a fertility index for male dibblers (Parantechinus apicalis) through the evaluation of urine samples to determine factors associated with breeding success in captivity (#438)

Tamara Keeley 1 , Lesley Shaw 2 , Lisa Mantellato 2 , Cathy Lambert 2
  1. University of Queensland, Gatton, QLD, Australia
  2. Native Species Breeding Program, Perth Zoo, Perth, WA, Australia

The endangered dibbler (Parantechinus apicalis) is a small dasyurid (~60-100 g) restricted to small island and mainland populations in Western Australia. Although urine evaluation has been used in marsupials to confirm the presence of spermatogenesis to define seasonality or confirm spermatogenesis for breeding purposes, no qualitative evaluations of spermatorrhoea have been published. The aim of this study is to increase our understanding of male dibbler reproductive physiology towards the development of an index of fertility to facilitate the evaluation of individual variation and the subsequent effects on captive breeding success.  Urine samples were collected from male dibblers (n = 24) every 2-4 weeks (dependant on ease of collection and timing of pairings) from late January to late May over two breeding seasons. Urine samples were evaluated for volume, sperm concentration and if large enough, osmolarity, pH, creatinine and testosterone. Although urinary pH was fairly consistent (6.3 ± 0.5), the volume collected (413.3 ± 221.8 µl), osmolarity (1236.3 ± 508.0 Osm/L) and sperm concentration (12,762.7 ± 26,081.1 sperm/ml) was highly variable both between and within individual males. Overall, urinary testosterone (7.0 ± 7.8 ng/mg creatinine) peaked in mid to late February but some individual males peaked about a month later which coincided with a similar trend in spermatogenesis. The variation in the timing of the initiation and cessation of spermatogenesis between males and the variable period in which females came into oestrus (late February to mid-April ) suggests that some records of unsuccessful matings or lower litter sizes may be attributed to asynchronous reproductive fertility between male and female dibblers in captivity. The collection of urine to evaluate spermatogenesis and reproductive hormones has the potential to quantify parameters associated with variable individual male fertility towards optimizing pairing choices and the quantification of puberty and senescence for marsupial species in the future.