Comparison of vent sexing and polymerase chain reaction for reliable sex determination in guinea fowls

The guinea fowl is an important poultry species with great economic potential in Africa. It is a monomorphic bird with less conspicuous sexual dimorphism. Inability to sex birds accurately early in their life imposes multiple challenges on breeding, conservation and production of these birds. Several methods have been employed for sexing monomorphic birds each with specific advantages and disadvantages. In the present study, sexes of 215 guinea fowls were determined by Polymerase Chain Reaction (PCR), Vent Sexing and determination of gonads. PCR was used to amplify a sequence homologous to Chicken EcoR1 fragment of 0.6 kb (EE0.6) using Universal Sex Primer (USP)1 and USP3 and internal control primers. Vent sexing could only diagnose 48.7 % of males accurately while it was able to diagnose females with an accuracy of 81%. Results from PCR was in complete agreement with sex indicated by gonads. Differences in results between PCR and vent sexing were significant (p < 0.05). Vent Sexing alone is not reliable for sexing guinea fowls prior to breeding decisions. Molecular sexing using the method described is recommended for accurate sex determination for breeders and researchers while future research is necessary to develop farmer friendly guidelines for reliable sex determination of guinea fowls. Original Scientific Paper. Received18 Jul 16; revised 20 Apr 17 Introduction The helmeted guinea fowl (Numida meleagris) is an important poultry species in West Africa. It is native to Africa and derives its name from Guinea Coast where it is believed to have evolved (Crowe, 1978). In Ghana guinea fowl is widely reared in the three Northern regions where small holder farmers make greater financial gains compared to raring chicken (Teye & Gyawu, 2001; FAO, 2014). It is an important source of income and protein and plays important socio-cultural, economic and nutritional roles for its keepers (Dei & Karbo, 2004; Avornyo et al., 2013; Dei et al., 2014). Due to its West African origin the indigenous population of this species is expected to be rich in adaptive genes representing a high degree of genetic variation.Guinea fowls are hardy, disease resistant (Jacob & Pescatore, 2013) and hence suitable for low input agriculture common in tropical countries. Demand for guinea fowl meat always exceeds the supply in Ghana (Karbo & Avornyo, 2006). Therefore, development of the guinea fowl industry plays a vital role in strategies to ensure food and nutrition security particularly in the Northern part of the country. However the development of the guinea fowl industry as a Ghana Jnl Agric. Sci. 52, 17-23 sustainable means of livelihood is limited by several challenges including inability to accurately sex guinea fowls (Teye et al., 2000). Moreki & Radikara (2013), described inability to sex guinea fowls as a challenge for commercialization of guinea fowl production in Africa. The guinea fowl is a monomorphic bird with no sexually dimorphic features expressed in early stages (Awotwi, 1975; Teye et al.,2000). Inability to determine sex of monomorphic birds results in multiple challenges in breeding, breed improvement and several other points in the guinea fowl value chain. Unless the sex of parents is known, guinea fowl keepers and breeders cannot maintain a good breeding stock for selection. Teye et al., (2000), reported that the inability to sex the birds early often leaves a flock with none or few females after sexing following methods used by farmers. It becomes difficult for breeders and farmers to introduce the correct sex ratio to ensure high fertility and hatchability. Cerit & Avanus (2007b), reported that difference in care cost of male and female and time spent for reproduction causes considerable financial losses in raring monomorphic birds. Thus, it is important to develop reliable methods for early sexing that can be easily adopted by farmers. Several methods have been used to sex monomorphic birds with varying degrees of accuracy including examining the cloacal duct, endoscopy, hormone determination, and cell gene analysis (Jones et al., 1984; Cerit & Avanus, 2007b). Laparoscopy yields the most reliable results although it can be harmful or lethal to the birds (Saino et al., 1999; Cerit & Avanus, 2007a). Faecal steroid sexing is expensive, largely depends on the method used while yielding accurate results only in breeding season with mature birds (Cerit & Avanus,