Conservation program
The poultry research facility “El Encín” belongs to the Department of Animal Breeding of INIA-CSIC. Created in 1957, the initial objective was the maintenance of commercial stocks of white egg layers and meat strains. When local breeds became progressively replaced by commercial hybrid lines, in 1975, the current Genetic Resources Conservation and Investigation Program of Spanish chicken breeds was initiated.
The objectives of this program are the conservation and genetic study of local breeds, and the expansion of local breed genetic resources to local producers that are interested in obtaining resilient animals highly adapted to the local Mediterranean climate. Currently, the “in vivo” conservation program includes 12 Spanish breeds of laying hens. (dual purpose)
Natural matings are performed with a ratio of one rooster to five hens, and roosters are rotated to guarantee an effective population size of approximately 100 to 300 depending on the breed. Eggs are collected in trap-nests.
Genetic studies carried out
The genetic studies carried out on these breeds are the following
- Genetic sexing of one-day-old chicks. Three synthetic chicken lines were created that express sex-linked genes that result in different patterns or colours in male and female chicks: barring, silver, and dermal melanin.
- External and internal egg quality. The conservation program has chicken breeds with low-cholesterol egg yolks, high shell strength, or dark shell colour with a low incidence of blood spots in yolks.
- Evaluation of stress resistance. Three welfare indicators are evaluated: tonic immobility, heterophil to lymphocyte ratio, and fluctuating bilateral asymmetry.
- Evaluation of genetic diversity, breed assignment and detection of crossbreeding or introgression events using molecular markers. Genes associated with plumage colour, and genetic markers for egg quality and resistance to stress are characterized.
Breeds included in the conservation program
Currently, twelve Spanish chicken breeds are included in the Genetic Resources Conservation and Investigation Program at the Experimental Station “El Encín”. The breeds are kept in free-range systems for the production of white, tinted, brown and dark brown eggs:
- White egg layer
Castellana Negra, Andaluza Azul, Andaluza Perdiz, Andaluza Franciscana, Española Cara Blanca.
- Tinted egg layer
Prat roja, Prat blanca, Pardo león, Castellana codorniz, Castellana codorniz silver.
- Brown egg layer
Vasca barrada y Villafranquina o Penedesenca roja.
The growing importance of alternative production systems has led to the recovery of indigenous breeds best adapted to the traditional production systems and the local environment, for which multinational companies do not offer a defined product.