Comparative analysis of silencing expression of myostatin (MSTN) and its two receptors (ACVR2A and ACVR2B) genes affecting growth traits in knock down chicken

Myostatin (MSTN), a growth differentiation factor-8 regulates muscular development through its receptors, ACVR2A (Activin receptor type IIA) and ACVR2B (Activin receptor type IIB) by inhibiting cellular differentiation of developing somites during embryonic stage and diminishing myofibriller growth during post-embryonic period. The objective of this study was to compare the effect of knockdown of expression of myostatin, ACVR2A and ACVR2B genes on growth traits in chicken. The shRNAs for Myostatin, ACVR2A and ACVR2B genes were designed, synthesized and cloned in DEST vector. The recombinant molecules were transfected into the spermatozoa and transfected spermatozoa were inseminated artificially to the hens to obtain fertile eggs. The fertile eggs were collected, incubated in the incubator and hatched to chicks. Silencing of ACVR2B gene showed significantly higher body weight than other single, double and triple knock down of genes in transgenic birds. The carcass traits such as dressing%, leg muscle%, and breast muscle% were found with the highest magnitudes in birds with silencing of the ACVR2B gene as compared to the birds with that of other genes and control group. The lowest serum cholesterol and HDL content was found in ACVR2B silencing birds. The total RBC count was the highest in this group though the differential counts did not differ significantly among various silencing and control groups of birds. It is concluded that silencing of only one receptor of MSTN particularly, ACVR2B may augment the highest growth in chicken during juvenile stage. Our findings may be used as model for improving growth in other food animals and repairing muscular degenerative disorders in human and other animals.