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Serial ultrasound examination of four mature female sevengill sharks (Notorynchus cepedianus) was carried out over 18 months. Monitoring the reproductive cycle and development of follicles and fetuses in sharks in a noninvasive manner using this technique has not been reported previously. Sharks were caught out of the "Oceanarium" tank by divers using a specially made catch-out bag, and brought to a holding area for examination. A behavior scoring system was used to monitor the impact of regular handling on the well-being of the animals. Ultrasound showed the growth and regression of follicles in sevengill ovaries, and allowed an approximation of the reproductive stage of these sharks. Monitoring behavior at five time points during the procedure showed that regular handling of sharks for clinical studies could be done with minimal impact on animal welfare. The ability to follow reproductive events in elasmobranches using ultrasonography is an important step in the application of assisted reproductive technology in these species. Assisted reproductive technology, such as monitoring female reproductive cycles and artificial insemination, could potentially be used to maintain genetic diversity and compliment aquaria-based breeding programs for endangered species such as the gray nurse shark (Carcharias taurus). Zoo Biol 26:383-395, 2007. (c) 2007 Wiley-Liss, Inc.

Non-invasive techniques were used to investigate the reproductive biology of captive squirrel gliders (Petaurus norfolcensis) for 3 months during the breeding season. The squirrel glider is a medium-sized marsupial glider of eastern Australia and is currently listed as a threatened species as a result of habitat destruction and fragmentation. Urinary cytology was used to determine the timing of oestrus, and the presence of sperm confirmed mating. Progesterone and oestradiol-17β were identified in faecal samples via thin-layer chromatography, and were used to characterise the reproductive cycle. Reproductive activity was observed in three of four females, with births occurring during June and July. A preoestrus increase in faecal oestradiol-17β was detected in a single female, whilst significant increases occurred post partum (±2 days) in two of four females, suggesting that the squirrel glider may undergo a postpartum oestrus. Faecal progesterone profiles showed low concentrations before oestrus and significantly elevated concentrations after oestrus, which were maintained throughout pregnancy. Parturition coincided with a decrease in progesterone concentrations (±1 day). This study successfully used non-invasive monitoring of urinary cytology and faecal steroids to define luteal and gestational length as 16–17 days, a previously unpublished detail.

Tetraploid bovine blastocysts were produced experimentally by electrofusion of in vitro matured and fertilized, zona‐enclosed two‐cell embryos (33–35 hr after initiation of sperm–egg incubation) using three fusion protocols. Field strengths of 1.0, 1.4, and 2.4 kV/cm were tested and the rate of fusion, subsequent cleavage, and blastocyst development were measured for each. High rates of fusion (76.5% ± 2.8%), cleavage (72.5% ± 7.4%) and blastocyst development (56.1% ± 6.4%) were achieved with the application of 1.4 kV/cm as a single 100‐μs pulse. Embryos were scored 30 and 60 min after stimulation for fusion. No time effect for fusion, cleavage, or blastocyst development was observed. Chromosome preparations of day 7 blastocysts revealed 12.5% of fused embryos were tetraploid. This is a significant increase from that found in nonfused embryos where spontaneous tetraploidy did not occur. An electrical stimulus of 1.0 kV/cm applied as two 50‐μs pulses produced significantly less one‐cell embryos (64.2% ± 3.0%) compared to 1.4 kV/cm while cleavage (79.9% ± 3.4) and blastocyst development (44.6% ± 4.0%) were not different from that for unexposed control embryos (89.5% ± 2.3% and 57.2% ± 3.2%, respectively). Embryos fused at 2.4 kV/cm applied as a single 30‐μs pulse (69.7% ± 5.7%) showed significantly lower cleavage (72.1% ± 3.7%) and blastocyst rates (40.2% ± 4.6%) compared to the unexposed control. Mol. Reprod. Dev. 56:372–377, 2000. © 2000 Wiley‐Liss, Inc.

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