Study of Polymorphism in Exon 1 and Exon 2 Ghrelin Gene and its Association with Growth Traits in Broiler Chickens

Ghrelin is a peptide hormone that is composed of 26 amino acids and leads to a positive energy balance and obesity through stimulation of releasing growth hormone, and increasing food intake and body weight. The purpose of this study was to determine and evaluate the association between the ghrelin gene polymorphism and growth traits in Ross and Cobb broiler chickens. Blood samples were collected from one hundred Ross and sixty Cobb chickens and their DNA was extracted using the modified salting-out chloroform method. Polymerase chain reaction (PCR) was carried out by specific primer pairs to amplify a 423bp fragment from a part of exon one and exon two of the ghrelin gene. The pattern of all samples was determined through single stranded conformation polymorphism (SSCP) analyses by Acrylamide gel using silver staining. Three different patterns were found in each strain. A, B, and C patterns with the frequencies of 0.2903, 0.4839 and 0.2258, and D, E and F patterns with the frequencies of 0.2889, 0.1333 and 0.5778 were found in Ross and Cobb strains, respectively. The associations between polymorphisms and the growth traits were evaluated using the GLM procedure of the SAS software. There was no significant association between the patterns and the growth traits