Polymorphism of Prolactin and Prolactin Promoter Genes and Its Association with Broodiness and Body Weight in Indonesian Chicken Lines

In the world of poultry farming, female chicken positioned as parent stock must exhibit excellent laying performance without broodiness and inherit body weight related traits to her offspring. Prolactin is widely accepted to have an important role in the onset and maintenance of broodiness event. The aim of this study is to identify a valuable genetic marker for studying the polymorphism of prolactin (Prl) and prolactin promoter (Prl-P) in Indonesian chicken lines using morphology and molecular data. Experimental chicken lines were produced from broiler (non-broodiness chicken line) and pelung (Indonesian native chicken; broodiness chicken line) selective breeding for five generations. The broodiness event and body weight of each generation of chicken lines were observed and compared with Brown Leghorn as a non-broodiness outgroup. The body weight of chickens were measured weekly from hatch to 49 days of age. Molecular data were archived using restriction fragment length polymorphism (RLFP) and single-strand conformation polymorphism (SSCP). After five generations of genetics selection, at 49 days, the body weight of experimental chicken lines and growth rate were decreased, while broody behavior occurrence was diminished. RFLP and SSCP analysis failed to differentiate broody to non-broody genotype and excellent to poor body weight in each generation due to the non-specific primer. Our conclusion is that broodiness is a recessive trait and can be eliminated by selective breeding