A GREAT new piece of technology has been developed at the University of New England that Poultry Hub Australia Director Tamsyn Crowley would like to share. Assoc Prof Wu and his team have developed a fast and accurate sexing method to sex chickens using feather crude DNA.
In recent years, researchers have found it difficult to source sexed day-old broiler chicks for research purposes. This was due to the change in genetics of current commercial broiler breeds resulting in feather sexing no longer being available. This has forced many researchers to use parent lines or as-hatched commercial broilers to study their nutritional needs and health.
However, issues would arise as parent lines may not respond to nutritional treatments and disease challenge in exactly the same way as commercial broilers. Vent sexing is being used as an alternate method to feather sexing, yet this method – though fast and accurate – requires highly trained and experienced personnel. In addition, most hatcheries were reluctant to allow vent sexers to sex a small number of birds on a regular basis for researchers due to biosecurity concerns.
Other sexing methods include in-ovo sexing, such as near-infrared fluorescence, Ramen spectroscopy oestrogen radio-immune assays and genetic engineering modification. These methods are technically complex and not feasible for research purposes where in-house hatching is not available for in-ovo sexing, and an engineered strain is not applicable. Therefore, a fast and relatively larger-scale sexing approach for research purposes was required.
Molecular sexing methods have shown the most promise in meeting these requirements. The method they developed is based on the fact that female birds are heterogametic (ZW), and males are homogametic (ZZ). The quick DNA extraction and fast PCR run makes it possible to sex birds quickly with the protocol including labelling the chicks, processing the samples and accurate call of genotypes. The DNA extraction procedure takes around 30 minutes with the basal part of chicken feathers, and the PCR procedure takes about 70 minutes for 100 birds.
The fact that they were able to successfully extract and use the crude DNA from feathers also makes this method favourable because it is a less invasive technique than extracting blood. The assay was validated and the accuracy confirmed by the HRM-sexing of 1318 broiler chicks that were used for nutritional and disease challenge trials performed at the University of New England, and the results were then verified by examining the sex of each bird upon dissection once the trials had been completed. The cost of this DNA sexing method was also minimal with an estimate of approximately $1 per bird for reagents and lab consumables.
Overall, Assoc Prof Wu and his team have developed a sexing protocol that can be used to sex chickens in a cost effective, accurate and fast way. This method can be implemented practically for large-scale use where hundreds of birds are needed, such as in nutrition and disease challenge trials. It is estimated that 500 to 800 birds can be DNA sexed within a day using this procedure and will provide researchers with the ability to make use of sexed birds in their trials. This will help to decrease the variation in experiments, resulting in a higher power to detect responses of the birds to the treatments under investigation.