Polymorphism in Exons of the Myostatin Gene and Its Relationship with Body Weight Traits in the Bian Chicken

Association analysis of production traits of Japanese quail (Coturnix japonica) using restriction-site associated DNA sequencing

This study was designed to perform an association analysis and identify SNP markers associated with production traits of Japanese quail using restriction-site-associated DNA sequencing. Weekly body weight data from 805 quail were collected from hatching to 16 weeks of age. A total number of 3990 eggs obtained from 399 female quail were used to assess egg quality traits. Egg-related traits were measured at the beginning of egg production (first stage) and at 12 weeks of age (second stage). Five eggs were analyzed at each stage. Traits, such as egg weight, egg length and short axes, eggshell strength and weight, egg equator thickness, yolk weight, diameter, and colour, albumen weight, age of first egg, total number of laid eggs, and egg production rate, were assessed. A total of 383 SNPs and 1151 associations as well as 734 SNPs and 1442 associations were identified in relation to quail production traits using general linear model (GLM) and mixed linear model (MLM) approaches, respectively. The GLM-identified SNPs were located on chromosomes 1-13, 15, 17-20, 24, 26-28, and Z, underlying phenotypic traits, except for egg and albumen weight at the first stage and yolk yellowness at the second stage. The MLM-identified SNPs were positioned on defined chromosomes associated with phenotypic traits except for the egg long axis at the second stage of egg production. Finally, 35 speculated genes were identified as candidate genes for the targeted traits based on their nearest positions. Our findings provide a deeper understanding and allow a more precise genetic improvement of production traits of Galliformes, particularly in Japanese quail.

High-throughput sequencing reveals crucial miRNAs in skeletal muscle development of Bian chicken

1. Growth performance is significant for chickens. MicroRNAs (miRNAs) have been found to play important roles in the post-transcriptional regulation of skeletal muscle growth. However, the mechanism of miRNAs in this process has not been elucidated.2. This study involved collecting leg muscle from slow- and fast-growing groups of Bian chicken at 16 weeks of age for high-throughput sequencing. A total of 42 differentially expressed miRNAs (DEMs) were identified. Among them, 22 DEMs were up-regulated and 20 DEMs were down-regulated.3. Biological process terms, relating to growth, were found by GO enrichment for target genes of DEMs and KEGG pathway analysis of target genes. This revealed some significantly enriched pathways closely related to skeletal muscle development, such as the calcium signalling pathway, ECM-receptor interaction, lysine degradation, apoptosis and tight junctions. Network interaction analysis of DEMs and target genes showed that the top fifty hub genes were targeted by thirteen DEMs.4. Four important miRNAs (novel_miR_158, novel_miR_144, novel_miR_291, and miR-205a) as well as some other valuable miRNAs, such as gga-miR-214 and gga-miR-3525 were identified. The qPCR results of five DEMs were highly consistent with that of sequencing between the two groups, which proved the reliability of miRNA-seq.5. The study will help to improve the molecular mechanism of miRNAs in chickens and guide future experiments concerning miRNA function in chicken growth.

Polymorphism of the Myostatin (MSTN) Gene in Landes and Kielecka Geese Breeds

Myostatin, also known as growth differentiation factor 8 (GDF8), belongs to the TGF-β superfamily of proteins. MSTN is a highly conserved protein that acts as a negative regulator of skeletal muscle growth. Loss of myostatin functionality causes the phenotype to appear in the form of 'double musculature', among others in cattle, sheep, and house mice. The presented results of the research were carried out on two geese breeds-Landes and Kielecka. The aim of the study was to identify mutations in the MSTN gene and study their impact on body weight in both geese breeds in different periods of life. Analysis of the obtained results showed the existence of polymorphism in exon 3 (c.1231C>T) and suggested a possible association (p < 0.05) between BW and genotype in 12 weeks of life in male Kielecka geese breed. The identified polymorphism may be one of the factors important for improving body weight in the studied Kielecka breed, therefore, it is necessary to conduct further research on a larger population of geese breeds in order to more accurately estimate the effect of the identified SNP c.1231C>T on BW in geese.

In ovo L-arginine supplementation stimulates myoblast differentiation but negatively affects muscle development of broiler chicken after hatching

In this study, we tested the hypothesis that in ovo feeding (IOF) of L-arginine (L-Arg) enhances nitric oxide (NO) production, stimulates the process of myogenesis, and regulates post-hatching muscle growth. Different doses of L-Arg were injected into the amnion of chicken embryos at embryonic day (ED) 16. After hatching, the body weight of individual male chickens was recorded weekly for 3 weeks. During in vitro experiments, myoblasts of the pectoralis major (PM) were extracted at ED16 and were incubated in medium containing 0.01 mm L-Arg, 0.05 mm L-Arg, and (or) 0.05 mm L-nitro-arginine-methyl-ester (L-NAME), an inhibitor of nitric oxide synthase (NOS). When 25 mg/kg L-Arg/initial egg weight was injected, no difference was observed in body weight at hatch, but a significant decrease was found during the following 3 weeks compared to that of the non-injected and saline-injected control, and this also affected the growth of muscle mass. L-NAME inhibited gene expression of myogenic differentiation antigen (MyoD), myogenin, NOS, and follistatin, decreased the cell viability, and increased myostatin (MSTN) gene expression. 0.05 mm L-Arg stimulated myogenin gene expression but also depressed muscle cell viability. L-NAME blocked the effect of 0.05 mm L-Arg on myogenin mRNA levels when co-incubated with 0.05 mm L-Arg. L-Arg treatments had no significant influence on NOS mRNA gene expression, but had inhibiting effect on follistatin gene expression, while L-NAME treatments had effects on both. These results suggested that L-Arg stimulated myoblast differentiation, but the limited number of myoblasts would form less myotubes and then less myofibers, while the latter limited the growth of muscle mass.

Effects of polymorphisms and haplotypes within the MSTN gene on duck growth trait

Abstract 1. Polymorphisms of the duck MSTN gene were investigated in 413 individuals by DNA sequencing and polymerase chain reaction restriction fragment length polymorphism. Four single nucleotide polymorphisms (G129A, C324T, A981G and C1002A), with A981G and C1002A completely linked, were found in the coding region. 2. Association analysis showed that different genotypes of all the identified SNPs were significantly associated with duck growth rate from week 5, 6 and 2 for G129A, C324T and A981G (C1002A), respectively. The greatest difference in body weight was 180 g at week 9, 106 g at week 8 and 123 g at week 8, respectively, for the three SNP's. 3. Linkage disequilibrium (LD) analysis indicated that C324T, A981G and C1002A were in strong LD. Nine main diplotypes from the reconstructed five main haplotypes were observed, and different diplotypes were significantly associated with growth rate from week 1. Birds with the h1h1 diplotype exhibited the largest body weight from week 1 onwards. 4. It was concluded that the duck MSTN gene was associated with body weight and is an important candidate gene for duck growth. traits and marker-assisted selection.