Semen analysis and successful artificial insemination in the St. Vincent amazon (Amazona guildingii)
The St. Vincent amazon (Amazona guildingii) is an endemic parrot on the Carribean island St Vincent. Due to poaching, trade, natural events such as hurricanes and habitat loss the species declined severely throughout the 20th century to a total number of 487 adult individuals and is currently regarded as vulnerable by IUCN. Captive breeding is attempted in terms of species conservation, but reproduction rates have been low due to reproductive problems such as mate aggression, asynchronous reproductive activity and infertile eggs. The aims of the present study were; firstly, to evaluate whether semen analysis might help to assess the fertility of males and to detect potential reasons for infertile eggs; secondly, to increase the number of offspring using artificial insemination, and as a future effect, to increase the presence of genetically valuable males in the ex-situ breeding population. For semen collection electric stimulation was used in 15 mature and healthy St. Vincent amazons with a success rate of 89% (202/227 attempts) in 14/15 males. Quality assessment of the semen included the evaluation of volume, pH, color, consistency and contaminations of the ejaculate, as well as estimation of motility, viability, morphology, concentration and total count of spermatozoa. Semen pH ranged from 6.7 to 7.5. Median sperm motility was 50% and median progressively forward motility 40%. Mean sperm concentration (x¯ ± SD) was 21,313.5 ± 22,408.8 spermatozoa/μl and mean sperm viability 66 ± 16%. Semen samples contained on average 20.5% morphologically normal spermatozoa and sperm malformations were detected mainly in the head (x¯ = 47.6%) and the tail regions (x¯ = 27.7%). Interestingly round bodies were detected in the ejaculates with a mean ratio of 0.6 round bodies per sperm. Semen analysis proved to be very useful to identify males with poor semen quality. Artificial insemination was performed 46 times in 9 females with either individual or pooled semen samples and 13 eggs from 7 females were laid afterwards. In 3 eggs, embryonic development was detected and 1 chick hatched successfully. Paternity testing confirmed the fatherhood of a one-winged semen donor male, a bird which was not able to copulate naturally. The results are very promising and underline that assisted reproduction techniques are a suitable tool for species conservation in captive breeding programs for psittacines.
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