T.K. Bhattacharya

Gene Expression and Polymorphism of Myostatin Gene and its Association with Growth Traits in Chicken

ABSTRACT Myostatin is a member of TGF-β super family and is directly involved in regulation of body growth through limiting muscular growth. A study was carried out in three chicken lines to identify the polymorphism in the coding region of the myostatin gene through SSCP and DNA sequencing. A total of 12 haplotypes were observed in myostatin coding region of chicken. Significant associations between haplogroups with body weight at day 1, 14, 28, and 42 days, and carcass traits at 42 days were observed across the lines. It is concluded that the coding region of myostatin gene was polymorphic, with varied levels of expression among lines and had significant effects on growth traits. The expression of MSTN gene varied during embryonic and post hatch development stage.

Activin receptor 2A and activin receptor 2B genes in chicken: effect on carcass traits

ABSTRACT Carcass traits are of immense importance in chicken as some parts of the carcass particularly breast muscle and legs are mostly preferred by the consumers with good market price while the remaining parts have a lower price. Carcass traits primarily depend on the growth of the birds, which are controlled by the candidate genes. Activin receptor type 2A and 2B act as receptors for binding with the members of transforming growth factor superfamily like myostatin to expedite its biological functions. We analysed exon2 and exon4 of activin receptor type 2A and 2B genes in six chicken populations. Both the genes revealed the presence of four haplotypes in these chicken populations. Association studies revealed a significant effect of genotypes and haplotypes on certain carcass traits such as carcass weight, dressing %, back and neck weight, giblet weights, etc. It is concluded that the exons of ACVR2A and ACVR2B genes were polymorphic and potentially associated with certain carcass traits in chicken.

Polymorphism and expression of insulin-like growth factor 1 (IGF1) gene and its association with growth traits in chicken

Abstract 1. The objectives of the study were to detect polymorphism in the coding region of the IGF1 gene, explore the expression profile and estimate association with growth traits in indigenous and exotic chickens. 2. A total of 12 haplotypes were found in Cornish, control layer and Aseel breeds of chicken in which the h1 haplotype was most frequent. 3. Nucleotide substitutions among haplotypes were found at 21 positions in the IGF1 gene in which 4 substitutions resulted in non-synonymous mutations in the receptor binding domain of the IGF1 protein. 4. The haplogroup showed a significant effect on body weight at 24 and 42 d of age in the control layer line, body weight at 42 d and daily weight gain between 29 and 42 d in the control broiler line, daily weight gain between 29 and 42 d in Cornish, and body weights at 42 d as well as daily weight gain between 29 and 42 d in Aseel birds. 5. IGF1 expression varied among the breeds during embryonic and post-hatch periods. The expression among the haplogroups varied in different chicken tissues. The effect of haplogroup on myofibre number in pectoral muscle was non-significant, although there was significant variation in numbers between d 1 and d 42, and between broiler and layer lines. 6. It was concluded that the coding region of the IGF1 gene was polymorphic, expressed differentially during the pre-hatch and post-hatch periods, and haplogroups showed significant association with growth traits in chicken.

Knock down of the myostatin gene by RNA interference increased body weight in chicken.

Myostatin is a negative regulator of muscular growth in poultry and other animals. Of several approaches, knocking down the negative regulator is an important aspect to augment muscular growth in chicken. Knock down of myostatin gene has been performed by shRNA acting against the expression of gene in animals. Two methods of knock down of gene in chicken such as embryo manipulation and sperm mediated method have been performed. The hatching percentage in embryo manipulation and sperm mediated method of knock down was 58.0 and 41.5%, respectively. The shRNA in knock down chicken enhanced body weight at 6 weeks by 26.9%. The dressing percentage and serum biochemical parameters such as SGPT and alkaline phosphatase differed significantly (P<0.05) between knock down and control birds. It is concluded that knocking down the myostatin gene successfully augmented growth in chicken.

Gene expression and silencing of activin receptor type 2A (ACVR2A) in myoblast cells of chicken

Abstract Activin receptor type 2A (ACVR2A) acts as receptor for myostatin (MSTN) protein involved in inhibiting satellite cell proliferation and differentiation. The importance of the ACVR2A gene during embryonic and post-hatch periods in broiler and layer chicken was studied in an in vitro cell culture system. The expression pattern of the ACVR2A gene during embryonic stages was similar in broiler and layer lines. Post-hatch expression of the ACVR2A gene varied significantly between broiler and layer lines. Five shRNA molecules were designed to knockdown expression of the ACVR2A gene in chicken myoblast cells. The silencing of the ACVR2A gene in a cell culture system varied from 60% to 82%. It is concluded that between broiler and layer lines, there were no significant changes in expression of the ACVR2A gene during embryonic stages but it varied significantly during the post-hatch period. The shRNA showed silencing of the ACVR2A gene under an in vitro cell culture system.

Role and Present Status of Biotechnology in Augmenting Poultry Productivity in India

India although has achieved self sufficiency in food grains, it has to solve the problems of protein-energy malnutrition for millions of people. Presently, poultry industry has emerged as a big hope, which can meet not only the protein requirement to millions but can provide employment and thereby, livelihood security. India is the 3rd largest producer of eggs and holds 5th position in poultry meat production in the world. Developments like emergence of molecular markers, structural and functional genomics, bioinformatics etc. in the field of the biotechnology have provided ample opportunity to peep into the molecular architecture of the individual birds. Improvement of poultry birds all together can be achieved through conventional breeding approach, but amalgamation of conventional and molecular approach can generate further improvement of birds in sustainable manners, which in turn augment productivity of the poultry very rapidly and efficiently bypassing the impact of climate change being faced by the whole world today.