Expression and polymorphism of Follistatin (FST) gene and its association with growth traits in native and exotic chicken.

Follistatin (FST), a member of the transforming growth factor beta super-family regulates body growth by inhibiting the binding of myostatin (an inhibitor of growth) with its receptor in chicken. An experiment was conducted to explore ontogenic expression of the follistatin gene, determine polymorphism at the coding region of the gene and estimate its effect on growth traits in native (Aseel) and exotic broiler (PD-1) and layer (White Leghorn) chicken. The significant differences of FST gene expression were observed among the breeds revealing significantly (p < 0.05) higher expression in PD-1 line followed by White Leghorn and Aseel breeds during both embryonic and post-hatch period. The polymorphism at the functional domain of the FST gene was identified with the presence of 4 haplotypes. The follistatin haplogroups had the significant effect on body weights (p < 0.05) at 42 days of age in the White Leghorn, PD-1 and Aseel breeds (h1h1 in PD-1, h1h4 in White Leghorn and h1h2 haplogroups in Aseel breeds had the highest body weights of 770.04 ± 12.96, 246.28 ± 7.60 and 270.00 ± 10.68 g, respectively). It is concluded that the follistatin gene expressed differently during the embryonic and post-embryonic period across the breeds and the coding region of the gene was polymorphic having significant effects on growth traits in chicken.