Indian Red Jungle fowl reveals a genetic relationship with South East Asian Red Jungle fowl and Indian native chicken breeds as evidenced through whole mitochondrial genome sequences.

Background: Native chickens are dispersed in a wide geographical range and have hereditary assets that are kept by farmers for various purposes. Mitochondrial DNA (mtDNA) is a widely utilized marker in molecular studies because of its quick advancement, matrilineal legacy, and simple molecular structure. Method and Results: We performed NGS sequencing to investigate mitochondrial genomes and to evaluate the hereditary connections, diversity, and measure of gene stream estimation in Indian native chicken breeds and Red Jungle fowl. The chicken breeds were genotyped using the D-loop region and 23 haplotypes were identified. When compared to Indian native breeds, more haplotypes were identified in the NADH dehydrogenase subunits, Cytochrome c oxidase, Cytochrome b, ATP synthase subunit 6, and Ribosomal RNA genes. The phylogenetic examination indicated that the analyzed chicken breeds were divided into six significant clades, namely A, B, C, D, E, and F, of which the F clade indicated the domestication of chicken breeds in India. Additionally, our work affirmed that the Indian Red Jungle Fowl is the origin for both reference Red Jungle Fowl as well as all Indian breeds, which is reflected in the dendrogram as well as network analysis based on the whole mtDNA and D-loop region. Indian Red Jungle Fowl is distributed as an outgroup, suggesting that this ancestry was reciprocally monophyletic. Conclusion: The mtDNA sequences of Indian native chickens provided novel insights into adaptation mechanisms and the significance of important mtDNA variations in understanding the maternal lineages of native birds.

Embryonic transcriptome unravels mechanisms and pathways underlying embryonic development with respect to muscle growth, egg production, and plumage formation in native and broiler chickens.

Background: Muscle development, egg production, and plumage colors are different between native and broiler chickens. The study was designed to investigate why improved Aseel (PD4) is colorful, stronger, and grew slowly compared with the control broiler (CB). Methods: A microarray was conducted using the 7th-day embryo (7EB) and 18th-day thigh muscle (18TM) of improved Aseel and broiler, respectively. Also, we have selected 24 Gallus gallus candidate reference genes from NCBI, and total RNA was isolated from the broiler, improved Aseel embryo tissues, and their expression profiles were studied by real-time quantitative PCR (qPCR). Furthermore, microarray data were validated with qPCR using improved Aseel and broiler embryo tissues. Results: In the differential transcripts screening, all the transcripts obtained by microarray of slow and fast growth groups were screened by fold change ≥ 1 and false discovery rate (FDR) ≤ 0.05. In total, 8,069 transcripts were differentially expressed between the 7EB and 18TM of PD4 compared to the CB. A further analysis showed that a high number of transcripts are differentially regulated in the 7EB of PD4 (6,896) and fewer transcripts are differentially regulated (1,173) in the 18TM of PD4 compared to the CB. On the 7th- and 18th-day PD4 embryos, 3,890, 3,006, 745, and 428 transcripts were up- and downregulated, respectively. The commonly up- and downregulated transcripts are 91 and 44 between the 7th- and 18th-day of embryos. In addition, the best housekeeping gene was identified. Furthermore, we validated the differentially expressed genes (DEGs) related to muscle growth, myostatin signaling and development, and fatty acid metabolism genes in PD4 and CB embryo tissues by qPCR, and the results correlated with microarray expression data. Conclusion: Our study identified DEGs that regulate the myostatin signaling and differentiation pathway; glycolysis and gluconeogenesis; fatty acid metabolism; Jak-STAT, mTOR, and TGF-ß signaling pathways; tryptophan metabolism; and PI3K-Akt signaling pathways in PD4. The results revealed that the gene expression architecture is present in the improved Aseel exhibiting embryo growth that will help improve muscle development, differentiation, egg production, protein synthesis, and plumage formation in PD4 native chickens. Our findings may be used as a model for improving the growth in Aseel as well as optimizing the growth in the broiler.

Silencing acetyl-CoA carboxylase A and sterol regulatory element-binding protein 1 genes through RNAi reduce serum and egg cholesterol in chicken.

Cholesterol is synthesized in chicken through de novo lipid biosynthetic pathway where two most important genes viz. SREBP1 and ACACA play immense role. To minimize cholesterol synthesis, RNAi approach was adopted and accordingly, we developed transgenic chicken possessing ACACA and SREBP1 shRNA constructs, which showed lower level of ACACA and SREBP1 in serum. The serum total cholesterol, triglycerides, HDL and LDL cholesterol was significantly lower by 23.8, 35.6, 26.6 and 20.9%, respectively in SREBP1 transgenic birds compared to the control. The egg total cholesterol and LDL cholesterol content was numerically lower in both ACACA and SREBP1 transgenic birds by 14.3 and 13.2%, and 10.4 and 13.7%, respectively compared to the control. It is concluded that the protocol was perfected to develop transgenic chicken through RNAi for knocking down the expression of ACACA and SREBP1 proteins, which minimized the cholesterol and triglycerides contents in serum and eggs.

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.

Cloning, characterisation and expression of the SERPINB14 gene, and association of promoter polymorphisms with egg quality traits in layer chicken.

1. Ovalbumin (SERPINB14) is the most abundant protein present in egg white contributing about 54% of the total egg protein. In this study, the objectives were to clone and characterise the coding sequence of the SERPINB14 gene, to explore its expression profile, identify polymorphisms in the promoter of the gene and explore any association with egg quality traits in White Leghorn chickens.2. SNPs and mRNA expression of SERPINB14 in White Leghorn chicken lines were detected by PCR-single strand conformation polymorphism (SSCP) along with sequencing and qPCR. The open reading frame (ORF) was cloned in an expression plasmid vector and sequenced.3. The ORF of this gene was 1161 bp encoding a peptide of 386 amino acids. There were three SNPs observed in the coding region of the gene, one of which was of the mis-sense type, having c562G>A transition which resulted in substitution of alanine to threonine at position 188 in the protein sequence. In both the lines, an increase in expression of the gene was observed after onset of egg production with peak expression at the 40th week of age compared to before onset of lay. The SERPINB14 gene was expressed in the magnum, but not in ovary and infundibulum, tissues of each White Leghorn line. The promoter region of the gene showed SNPs with three haplotypes; H1, H2, and H3. The haplo groups were associated with the egg weight and age at sexual maturity in the IWI line and Haugh unit and albumin index in the IWK line.4. It was concluded that the ORF of SERPINB14 gene in White Leghorn chicken lines is polymorphic. The promoter region of the gene is also polymorphic and has significant (P < 0.05) association with Haugh unit and egg weight in IWK and IWI chicken lines, respectively.

Analysis of (co) variance components and estimation of breeding value of growth and production traits in Dahlem Red chicken using pedigree relationship in an animal model.

Variance and covariance components of growth and production traits were analyzed employing REML animal model to assess the Dahlem Red (PD-3) chicken population for direct additive genetic, maternal effects and to estimate the estimated breeding value (EBV), genetic parameters, genetic trends and rate of inbreeding (ΔF) utilizing seven generation's data. The generation and hatch had significant (P≤0.01) effect on the body weight at 0 day (BW0), 2 (BW2), 4 (BW4) and 6 weeks (BW6) and shank length at six weeks of age (SL6). The average least squares means (LSM) for BW6 and SL6 were 273.93±0.62 g and 53.97±0.05 mm, respectively. All the production traits were significantly (P≤0.01) influenced by generation and hatch. The average LSM for age at sexual maturity (ASM), egg production up to 40 weeks (EP40) and egg mass up to 40 weeks (EM40) were 168.82±0.25 d, 72.60±0.41 eggs and 4.21±0.07 kg, respectively. Model 5 with additive direct, maternal genetic, maternal permanent environmental and residual variance components was the best for BW0, BW2 and BW4 based on the AIC values obtained in WOMBAT. Model 4 was the best model for BW6, SL6, ASM, EP40 and EM40 with additive direct, maternal permanent environmental and residual variance components. Maternal effects were higher during early age, decreased with age, and remained present until 20 weeks of age. The heritability (h2) estimates were low to moderate in magnitude for all the growth traits and ranged from 0.02±0.03 to 0.19±0.03. The maternal heritability was high at hatch (0.35±0.06), decreased gradually until 4th week (0.02±0.01) and ceased afterwards. The heritabilities of EP40 (0.11±0.03) and EM40 (0.12±0.04) were low. The direct additive genetic correlations (ra) between BW2, BW4, BW6 and SL6 were high and positive (P≤ 0.05). The additive genetic and maternal permanent environmental correlation between EP40 and EM40 were high and positive (P≤ 0.05). The EBV of EM40 was significant (P≤ 0.05) with 0.48 kg/generation in PD-3 chicken at the end of the seventh generation. The EBV of EP40 showed an increasing trend with a genetic gain of 1.87 eggs per generation. The average inbreeding coefficient of the population was 0.019 and average ΔF was 0.007 over the last seven generations of selection. The EBV trends for primary and associated traits showed linear trends in the desired direction and negligible inbreeding.

Backyard poultry farming for sustained production and enhanced nutritional and livelihood security with special reference to India: a review.

A comprehensive review on backyard poultry farming (BYPF) was carried out with respect to history, status, production systems, management practices, role in socio-economic development, etc., considering the Indian scenario in particular. Backyard poultry is an age-old traditional practice where small numbers of native chickens are reared with or without inputs under the free-range scavenging conditions. Currently, BYPF contributes about 17.8% (18.41 billion) of the total egg production (103.32 billion) of India. The introduction of high yielding chicken varieties, which resemble the native chicken, transformed the BYPF into a highly remunerative farming activity. The BYPF has a proven potential to alleviate poverty, eradicate malnutrition, empower women, and provide subsidiary income, and gainful employment in rural and tribal areas. In India, four types of backyard poultry farming are practiced, i.e., traditional, small-scale rural, small-scale intensive, and native chicken farming. The aspects of breeding and nutritional strategies in the nursery, and free-range conditions, besides the housing and health care practices that are followed in India, are discussed in detail. Backyard poultry farming has huge potential for further expansion as the produce from this system is preferred across the country.

Inheritance of growth traits and impact of selection on carcass and egg quality traits in Vanashree, an improved indigenous chicken.

The present study was carried out to assess the inheritance of growth traits and to study the effect of selection on carcass characteristics and egg quality traits in Vanashree, an improved indigenous chicken. Estimates of heritability were high for body weights recorded at 4, 5 and 6 weeks of age and 8th week shank length, while it was moderate for 8th week body weight. Estimates of heritability on sire component of variance declined as age increased from 4 to 8 weeks of age. The genetic and phenotypic correlations among various growth traits were positive and high in magnitude. The body weight continued to increase up to 40 weeks of age particularly in male birds, while there was little increase in shank length from 20 to 40 weeks of age particularly in hens. There was no significant change in carcass characteristics and egg quality traits except that there was some improvement in dressing percentage over the generations. Sex effect was significant on relative weights of the breast, legs, gizzard, liver and heart and abdominal fat percentage. There was increase in Haugh unit and albumen index, yolk percentage, yolk to albumen ratio and yolk colour in the present generation. The results suggest that there is adequate additive genetic variation for growth traits in the population and that Vanashree chicken could continue to be improved so as to make it a promising dual purpose purebred indigenous chicken for increasing the productivity of free range or semi-intensive systems of production.

Genetic analysis of growth and egg production traits in synthetic colored broiler female line using animal model.

Variance and genetic parameters were estimated for growth and production traits of synthetic broiler female line (PB-2) using REML animal model to delineate the population status, direct additive, maternal genetic, permanent environmental effects, besides genetic trends and performance of economic traits. The overall least squares mean (LSM) for body weights at 0 day (BW0), at 2 weeks (BW2), at 4 weeks (BW4), at 5 weeks (BW5), shank length at 5 weeks (SL5), and breast angle at 5 weeks (BA5) of age were 40.03 g, 207.40 g, 589.58 g, 828.51 g, 76.89 cm, and 80.78°, respectively. The overall LSM for egg production up to 40 weeks of age (EP40) and egg weight at 40 weeks (EW40) were 66.02 eggs and 58.23 g, respectively. The heritability estimates using the best model for BW0, BW2, BW4, BW5, SL5, and BA5 were 0.06 ± 0.03, 0.19 ± 0.03, 0.15 ± 0.03, 0.14 ± 0.02, 0.08 ± 0.02, and 0.02 ± 0.01, respectively. The heritability estimates were low to moderate in the magnitude for all early growth traits. The heritability estimate for egg production up to 40 weeks (EP40) was 0.30 ± 0.05. The heritability estimates for adult body weights at 20 and 40 weeks of age (BW 20 and BW 40), age at sexual maturity (ASM), and egg weight at 40 weeks (EW40) were 0.21 ± 0.04, 0.19 ± 0.04, 0.16 ± 0.03, and 0.33 ± 0.05, respectively, and the estimates were moderate to high in magnitude. Model 4 with additive, maternal permanent environmental, residual, and phenotypic effects was the best model for growth traits except for BW0 and BA5. The average genetic gain observed in primary trait (BW5) over the five generations was 13.62 g per each generation indicating effective selection. The animal model minimized the overestimation of genetic parameters and improved the accuracy of the BV, thus enabling the breeder to select the suitable breeding strategy for genetic improvement.

Molecular characterization and computational structure prediction of activin receptor type IIB in aseel and broiler chicken.

The present study was formulated to characterize and comprehend the molecular structural characteristics of ACTRIIB receptor in Aseel and control broiler (CB) populations. The full length coding sequence (1539 bp) of the receptor was amplified, cloned, sequenced and analyzed using bioinformatic tools. The physico chemical properties of protein and structural features like secondary structure, solvent accessibility and disorder regions were computed. The 3D structure was predicted by I-TASSER and evaluated by Ramachandran Plot and tools under Structural Analysis and Verification Server. The nucleotides differences between CB and Aseel were c. [156G > A; 210 T > C; 493C > T; c.520G > C; 665A > C; 686G > A; 937C > G; 1011A > C; 1130A > G; 1208 T > A; 1326 T > C; 1433 T > C]. The amino acid substitutions between CB and Aseel were p. [(Pro165Ser; Glu174Gln; Gln222Pro; Ser229Asn; His313Asp; Gln377Arg; Val403Asp; and Ile478Thr)]. While, the silent changes includes p. [(Lys53=; Glu71=; Leu337=; Asp442=)]. The molecular weight of mature protein was predicted to be 55.51 kDa and 57.80 kDa in Aseel and CB, respectively. The higher rank 3D model had a C-score of -1.60 in Aseel and - 1.41 in CB, while the estimated TM-score (0.54 ±â€¯0.14) and RMSD (5.8 ±â€¯1.2 Å) were found to be similar in Aseel and CB. Among the 512 residues, >90% were in favored region, 4.7% in allowed region and <1.5% in disallowed region in both Aseel and CB. The pattern of contact map was comparable in Aseel and CB. The Hydrogen bond plots of the Aseel and CB shared similar secondary structure pattern. The ACTRIIB protein was predicted to interact with ACVR1B, ACVR1C, INHBA, SMAD 1,2,5,7 & 9 and BMPR1A&B. Clustal and phylogenetic analysis implied that both the lines were closely related and formed a sub cluster with in avian cluster. The current research provides insights about structural and functional aspects of the receptor and also aids in understanding the evolutionary history of ACTRIIB.

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.

In silico prediction of short hairpin RNA and in vitro silencing of activin receptor type IIB in chicken embryo fibroblasts by RNA interference.

Gene silencing by RNA interference is extensively used reverse genetic approach to analyse the implications of any gene in mammalian systems. The silencing of the Activin type IIB receptor belonging to transforming growth factor beta superfamily has demonstrated increase in muscle growth in many species. We designed five short hairpin RNA constructs targeting coding region of chicken ACTRIIB. All the shRNAs were transfected into chicken embryo fibroblast cells and evaluated their silencing efficiency by real time PCR and western blotting. Initially the computational analysis of target region and shRNA constructs was undertaken to predict sequence based features (secondary structures, GC% and H-b index) and thermodynamic features (ΔGoverall, ΔGduplex, ΔGbreak-target, ΔGintra-oligomer, ΔGinter-oligomer and ΔΔGends). We determined that all these predicted features were associated with shRNA efficacy. The invitro analysis of shRNA constructs exhibited significant (P < 0.05) reduction in the levels of ACTRIIB at mRNA and protein level. The knock down efficiency of shRNAs varied significantly (P < 0.001) from 83% (shRNA 1) to 43% (shRNA 5). All the shRNAs up regulated the myogenic pathway associated genes (MyoD and MyoG) significantly (P < 0.05). There was significant (P < 0.05) up-regulation of IFNA, IFNB and MHCII transcripts. The ACTRIIB expression was inversely associated with the expression of myogenic pathway and immune response genes. The anti ACTRIIB shRNA construct 1 and 3 exhibited maximum knock down efficiency with minimal interferon response, and can be used for generating ACTRIIB knockdown chicken with higher muscle mass.

Polymorphisms in GnRHI and GnRHII genes and their association with egg production and egg quality traits in chicken.

1. Two candidate genes, namely, Gonadotropin releasing hormone I (GnRHI) and Gonadotropin releasing hormone II (GnRHII) play pivotal roles in ovulation and egg production in chicken. The objective of this study was to explore polymorphism in these genes and to estimate the effects of polymorphism of these two genes on egg production and egg quality traits in White Leghorn laying hens. 2. Single strand conformation polymorphism followed by sequencing was performed to detect polymorphism in these genes. 3. The coding regions of the GnRHI and GnRHII genes were found to be polymorphic. In the GnRH1 gene, 12 haplotypes were determined, of which the h1 haplotype was predominant and the h5, h9 and h11 haplotypes were the least frequent ones. In the GnRHII gene, eight haplotypes were found, of which the h1 haplotype was the most frequent and the h6 was the least frequent haplotype in the White Leghorn population. 4. The haplogroups of GnRHI had a significant effect on body weight and egg production up to 64 weeks of age, yolk content, Haugh units and egg shell parameters. The h1h2 haplogroup of the GnRHI gene showed the highest egg production, with 211.0 ± 24.3 eggs up to 64 weeks of age, while the highest yolk content and Haugh unit was found in h3h10 haplogrouped birds. The haplogroups of GnRHII had a significant effect on age at sexual maturity (ASM) where the shortest ASM was found in the h1h4 birds (147.3 ± 5.9 d) and the longest ASM was observed in the h1h3 birds (160.6 ± 23.4 d). 5. It was concluded that GnRHI and GnRHII genes are polymorphic and have a significant effect on body weight, egg production and egg quality traits in White Leghorn laying hens.

In vivo cell-mediated immune, hemagglutination inhibition response, hematological and biochemical values in native vs. exotic chicken breeds.

Birds (364) of both sexes, 11-wk-old, belonging to 2 native (Brown Nicobari and Ghagus) breeds and 1 exotic breed (Dahlem Red) were evaluated for cell-mediated immune response (CMI) by phytohemagglutinin-P (PHA-P), hemagglutination inhibition (HI) assay against Newcastle disease virus (NDV) antigen (LaSota stock virus), flow cytometric analysis of CD8+ cytotoxic T lymphocytes (CTLs), and hematology and biochemical assays. The cutaneous basophil hypersensitivity response PHA-P% increase in wattle thickness (mm) was highest in Ghagus (431.14 ± 22.56) which differed significantly with that of Brown Nicobari (269.1 ± 22.66) and Dahlem Red (218.42 ± 22.30). Sex-wise observation showed that females are having significantly higher response than males. Hemagglutination inhibition test was performed to determine the serum antibodies against Newcastle disease (ND) virus. Brown Nicobari showed highest HI antibody titer than Ghagus and Dahlem Red to similar vaccination program after booster NDV dose. Flow cytometry assay revealed significantly higher CTLs proliferation in Brown Nicobari than Ghagus and Dahlem Red. Moreover, CTLs were found to be higher in control group than the treatment group. Other hematological parameters (103/µL) significant difference was found in white blood cell count between Dahlem Red (38.41 ± 1.03) with that of Brown Nicobari (35.28 ± 1.04) and Ghagus (34.57 ± 1.04) in treatment groups. Same trend was observed in the Lymphocyte treatment group. However, in Granulocyte treatment group, Brown Nicobari (11.04 ± 0.35) was found to be significantly different from Dahlem Red (8.68 ± 0.34) and Ghagus (9.27 ± 0.35). Correlations between body weight at 11 wk of age and CMI, HI, cytotoxic T cell were -0.093, 0.047, and -0.036, respectively. Egg weight was found to be positively correlated with that of chick weight. Serum biochemical values showed that Dahlem Red was having significantly higher creatinine levels compared to Ghagus. Triglycerides level was also significantly higher in Ghagus compared to Dahlem Red. No significant breed effect was observed for alkaline phosphate, aspartate transaminase, and alanine transaminase. Cholesterol and total serum protein levels were significantly higher in Dahlem Red compared to Brown Nicobari.

Molecular characterization and expression profiling of BMP 3 gene in broiler and layer chicken.

A study was carried out to characterize and explore the expression profile of BMP 3 gene in control broiler and control layer chicken. The total open reading frame of BMP 3 (1389 bp) was cloned and sequenced. The control broiler and control layer chicken showed variation at nucleotide and amino acid level with reference gene (Gallus gallus, NCBI Acc. No. NM_001034819). When compared to reference gene, the control broiler showed four nucleotide differences (c.192A>G, c.519C>T, 903G>A and 960C>G), while, control layer showed variation at c.33G>C, 192A>G, 858G>A, 904G>A, 960C>G and 1257C>T making six differences in total. However, between control broiler and control layer lines, nucleotide differences was observed at c.33G>C, 519T>C, 858G>A, 903A>G, 904G>A and 1257C>T. The change at amino acid level between reference and control broiler was p.D320N and with control layer chicken, it was p.D302N and p.D320N. On the other hand, a single amino acid difference (p.D302N) was observed between the control broiler and control layer chicken lines. The phylogenetic study displayed a close relationship between broiler and layer lines and reference gene and also with other avian species resulting in a cluster formation. These cluster in turn displayed a distant link with the mammalian species. The expression profile of BMP 3 gene exhibited a variation at different stages of embryonic development and also at post embryonic period among the lines with control layer showing higher expression than that of broiler chicken. The protein was also detected in bone marrow tissue of broiler and layer lines by western blotting. It is concluded that the BMP 3 gene sequence differed at nucleotide and amino acid level among the lines and the gene expressed differentially at different periods of embryonic development and also at post hatch period.

Pattern recognition receptor genes expression profiling in indigenous chickens of India and White Leghorn.

Pattern recognition receptors (PRR) such as Toll-like receptors, NOD-like receptors, RIG-I helicase receptors, and C-type lectin receptors play a critical role in innate immunity as a first line of defense against invading pathogens through recognition of pathogen and/or damage-associated molecular patterns. Genetic makeup of birds is known to play a role in resistance or susceptibility to various infectious diseases. Therefore, the present study was carried out to elucidate the differential expression of PRR and some of the cytokine genes in peripheral blood mononuclear cells of indigenous chicken breeds such as Ghagus and Nicobari and an exotic chicken breed, White Leghorn (WLH). The stability of expression of reference genes in peripheral blood mononuclear cells of 3 breeds was first determined using NormFinder and BestKeeper programs. NormFinder determined B2M and G6PDH reference genes as the best combination with stability value of 0.38. Out of total 14 genes studied, expression of ten genes was found to be significantly different among 3 breeds after normalization with these reference genes. Ghagus breed showed higher level of expression of TLR1LB, TLR7, NOD1, NOD5, B-Lec, IFNß, IL1ß, and IL8 genes when compared to Nicobari breed. Further, Ghagus showed higher expression of TLR1LB, MDA5, LGP2, B-Lec, IL1ß, and IL8 genes as compared to WLH breed. Higher expression of LGP2 and MDA5 genes was observed in Nicobari compared to the WLH breed while higher expression of TLR7, NOD1, NOD5, and IFNß genes was observed in WLH as compared to Nicobari breed. No difference was observed in the expression of TLR1LA, TLR3, B-NK, and IFNα genes among 3 breeds. Study revealed significant breed effect in expression profile of PRR and some of the cytokine genes and Ghagus breed seems to have better expression profile of these genes linked to the innate immunity when compared to the WLH and Nicobar breeds.

Characterization of indigenous Aseel chicken breed for morphological, growth, production, and meat composition traits from India.

Aseel is an important native chicken breed of India, known for its martial qualities (aggressive fighting abilities), pugnacity, and majestic gait. The aim of the study is to conserve and characterize the Aseel germplasm, which is considered to be endangered. The birds were maintained on deep litter under a simulated backyard type of housing having night shelter and a free-range area. A total of 313 chicks produced in the second generation from the flock collected from native tract in Andhra Pradesh was characterized for morphological, growth, production, and meat quality parameters. Aseel birds were characterized by multicolored plumage (predominantly dark brown, black, golden, etc.) with solid feather patterns and normal distribution. Ear lobes were red (92%) and small in size, while 98% of the birds had red colored pea combs with variations in intensity of color. The shank color was yellow in the majority (65%) of the birds. The skin color was white (98%) with pinkish red coloration on exposed body parts, especially on the breast. The fertility and hatchability on total eggs were 67.2 and 41.4%, respectively. Cocks were heavier (P ≤ 0.05) with distinct sexual dimorphism in Aseel. The body weight of hens and cocks was 1,704.4 ± 23.2 and 2,702.5 ± 28.1 g at 40 wk and 2,333.7 ± 26.1 and 3,793.7 ± 20.8 g at 72 wk of age, respectively. The age at sexual maturity was 214.0 ± 6.0 days. The egg production up to 40, 52, and 64 wk of age was 18.0 ± 1, 30.0 ± 2.0, and 47 ± 3 eggs, respectively. The annual egg production (72 wk) was 64 ± 6 eggs. The proximate composition of breast muscle was; protein 21.5 ± 0.5%, fat 3.4 ± 0.1%, ash 2.0 ± 0.1%, and moisture 73.3 ± 0.5%. The pH of breast muscle was 6.0 ± 0.03 and the cholesterol content was 72.5 ± 6.7 mg/100 g. Efforts are on for improving the productivity in the flock without compromising the original breed characteristics.

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.

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.

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

Myostatin is a member of TGF-ß 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.