Methodologies to identify, evaluate and conserve poultry genetic resources

An increasing loss of genetic diversity has been observed for all agriculturally used species, and poultry genetic resources are considered to be one of the most endangered. Conservation of domestic animal diversity must encompass identifying, characterising and monitoring genetic resources for their best short-term use, whilst ensuring their long-term ready availability. As an important first step to describe the existent resources, country surveys were done as initiated by FAO, and these data were collected in the FAO Global Data Bank for Farm Animal Genetic Resources. Efficient methods have been developed to quantify genetic structure of genetic resource populations. Thereby, biodiversity can be described at several levels, from phenotypic observations to molecular data. Recently, molecular techniques have become available, and the most widely used technique is currently the genetic characterisation of populations at a range of microsatellite loci. Single nucleotide polymorphism (SNP) in genes and non-coding parts of the genome is considered as a worthwhile tool for the biodiversity assessment. A significant methodological way in studying poultry breed biodiversity is thought to be the system approach in planning experiments and analysing results. Another important step for the sustainable management of genetic resources is the establishment of conservation measures in situ as living populations or ex situ as cryopreserved material. The conservation methodologies seem to be especially critical in the third world countries where losses of native genetic resources may have a dramatic impact on sustainable development of animal production. By 2000, 118 active conservation programs were listed by FAO for the five major avian species. Technologies for storage of frozen semen in chicken and turkey have been under development for decades, but their large-scale application in conservation measures of poultry genetic resources has not yet taken place. Cryopreservation of chicken and turkey semen as partly used by commercial breeders are of considerable interest in preserving genetic diversity, even fertilising ability obtained from frozen-thawed poultry spermatozoa is limited compared to mammalian species, in particular cattle, and varies obviously between breeds. Laboratory techniques to preserve other avian cells, such as somatic cells and primordial germ cells, are under investigation, but cryopreservation of embryos seems not to be successful.