Semen collection and polymerase chain reaction-based sex determination of black-headed and straw-necked ibis.

This study aimed to develop a polymerase chain reaction (PCR)-based sexing and effective semen collection methods for black-headed and straw-necked ibis species. However, most birds are not sexually dimorphic, that is, the sexes appear similar. Therefore, the gender should be determined before semen collection. DNA was extracted from the blood samples of 11 black-headed and 4 straw-necked ibis. The sex was determined after PCR amplification of the EE0.6 region of W-chromosome. The PCR products were separated using gel electrophoresis. A single band indicated the presence of the EE0.6 region and that the individual was a female, while no band indicated that the individual was a male. Further, the single bands from seven specimens were amplified. Semen collection was performed by massage or a combination of massage with electro-ejaculation and was attempted during all four seasons. The semen was successfully collected in March from male straw-necked ibis using the massage method. Limited motility, viability and concentration of straw-necked ibis sperm were observed. The sperm length was 180 μm and that of the nucleus was 30 μm with acrosome located at the tip of the nucleus. Thus, the PCR-based sexing proved to be an accurate molecular sexing method for black-headed and straw-necked ibis. Furthermore, we successfully collected semen and observed the stained sperm nucleus and acrosome of the straw-necked ibis sperm. We propose that the use of this PCR methodology can be applied as a routine method for sex determination and semen collection in ibis species for future ecological research. However, considering our limited success, further studies on semen collection method are required.