Relationship between the expression levels of myogenic regulatory factor genes and carcass characteristics in Kivircik and Hungarian Merino lambs

This study aimed to investigate the expression profiles of the myogenic regulatory genes MYOD1, MYOG, MYF5, MYF6, and MSTN in longissimus dorsi muscle, as well as the correlation of the expression levels of these genes with carcass characteristics and growth performance in the Kivircik and Hungarian Merino sheep breeds. The expression levels of the MYF5, MYF6, and MYOG genes were found to be significantly correlated with the rib proportion, the expression level of the MYOG gene was identified as being the main determinant of variations in the rib proportion in the Kivircik lambs. The regression analysis results revealed that the expression levels of the MYF5 and MSTN genes played an essential role in determining the cold carcass dressing percentage in Hungarian Merino lambs. Further, as a result of the regression analysis, the model including the expression level of the MYF6 gene demonstrated that this gene could be responsible for 36.4% of the differences observed in cold carcass weight. In conclusion, the findings of this study suggest that the expression levels of the MYF5, MYF6, and MYOG genes were associated with various carcass traits, particularly in the Kivircik breed, and these genes hold potential as markers for enhancing breed productivity.

Association of polymorphisms in lipid and energy metabolism-related genes with fattening performance in Simmental cattle

Lipid and energy metabolism are major constituents of mammal growth and thus fattening performance of cattle. This study was designed to evaluate the effects of polymorphisms in lipid and energy metabolism-related genes including oxidized low-density lipoprotein receptor 1 (OLR1), lactoferrin (LTF), stearoyl-CoA desaturase (SCD), beta-lactoglobulin (LGB), thyroglobulin (TG), annexin A9 (ANXA9), myogenic factor 5 (MYF5), protein kinase AMP-activated non-catalytic subunit gamma 3 (PRKAG3), and pituitary-specific transcriptional factor 1 (PIT1), on fattening performance in Simmental cattle. A total of 72 purebred Simmental bulls with a similar initial age and weight were fattened on the same farm for 10 months. Association analysis was performed using linear mixed models. The OLR1 marker was significantly associated with the final weight (FW), hot carcass weight (HCW), chilled carcass weight (CCW), dressing percentage (DP), and total weight gain (TWG). SCD affected the FW, TWG, and average daily live weight gain (ADWG). The present results clearly demonstrated the significant impact of the TG marker on fattening performance. It was highly significantly associated with the FW, HCW, CCW, and TWG. The SCD × TG and the OLR1 × TG interactions had remarkable effects on the traits analyzed. The GACC and CCCC haplotypes of the SCD × TG and OLR1 × TG, respectively, were found to be powerful markers for fattening performance in Simmentals. Novel associations in this study may be useful for further genetic evaluations to improve beef cattle breeding.

Bibliometric Analysis of Research on the Main Genes Involved in Meat Tenderness

Simple Summary

A bibliometric analysis was carried out to know the evolution of research on genes associated with meat tenderness, of interest for the development of selection programs. Since 1993, studies have been limited to a few researchers in high-income countries due to the costs associated with the techniques. The main findings showed that the scientific production had a discontinuous growth because science experienced a significant change since approximately 2010. Marker-assisted selection was widely used, evaluating mainly CAPN (calpain) and CAST (calpastatin) genes for their contribution to meat tenderness, especially in cattle. However, the effects are small; therefore, genomic selection was implemented by genotyping thousands of single nucleotide polymorphisms (SNPs) for further explanation of genetic variation. The results shown are important for scholars to identify emerging methodologies and gaps in the literature and to know who the prolific authors and institutions in the field for possible collaborations, etc., are.

Abstract

Tenderness is one of the main characteristics of meat because it determines its price and acceptability. This is the first bibliometric study on the trend of research on the role of genes in meat tenderness. A total of 175 original and English-language articles published up to 2021 were retrieved from Scopus. The bibliometric analysis was carried out with VOSviewer (version 1.6.18, Eck and Waltman, Leiden, Netherlands) and complemented with the Analyze search results service from Scopus. Erroneous and duplicate data were eliminated, and incomplete information was added to standardize the results. Scientific production was evaluated by means of quantity, quality and structure indicators. As a first glance, 8.816% of authors have published more than 50% of papers mainly related to genes encoding the calpain (CAPN)-calpastatin (CAST) system and single nucleotide polymorphisms (SNPs). Among other findings, a strong link was found between the contribution of the main countries (led by the United States with) and their institutions (led by the USDA Agricultural Research Service with) to their gross domestic product. Most studies on the topic are published in the Journal of Animal Science, and other journals with high impact according to the number of citations and different metrics. Finally, when evaluating the most cited articles, the occurrence and association of the main keywords, it was confirmed that research is focused on the role of CAPN and CAST genes and of SNPs in beef tenderness. The change in science was emphasized; although marker-assisted selection is still used, genes have an infinitesimal effect on complex traits. Therefore, since about 2010, new research groups adopted genomic selection to evaluate dense panels of SNPs and better explain genetic variation in meat tenderness.

Key Genes Regulating Skeletal Muscle Development and Growth in Farm Animals

Simple Summary

Skeletal muscle mass is an important economic trait, and muscle development and growth is a crucial factor to supply enough meat for human consumption. Thus, understanding (candidate) genes regulating skeletal muscle development is crucial for understanding molecular genetic regulation of muscle growth and can be benefit the meat industry toward the goal of increasing meat yields. During the past years, significant progress has been made for understanding these mechanisms, and thus, we decided to write a comprehensive review covering regulators and (candidate) genes crucial for muscle development and growth in farm animals. Detection of these genes and factors increases our understanding of muscle growth and development and is a great help for breeders to satisfy demands for meat production on a global scale.

Abstract

Farm-animal species play crucial roles in satisfying demands for meat on a global scale, and they are genetically being developed to enhance the efficiency of meat production. In particular, one of the important breeders’ aims is to increase skeletal muscle growth in farm animals. The enhancement of muscle development and growth is crucial to meet consumers’ demands regarding meat quality. Fetal skeletal muscle development involves myogenesis (with myoblast proliferation, differentiation, and fusion), fibrogenesis, and adipogenesis. Typically, myogenesis is regulated by a convoluted network of intrinsic and extrinsic factors monitored by myogenic regulatory factor genes in two or three phases, as well as genes that code for kinases. Marker-assisted selection relies on candidate genes related positively or negatively to muscle development and can be a strong supplement to classical selection strategies in farm animals. This comprehensive review covers important (candidate) genes that regulate muscle development and growth in farm animals (cattle, sheep, chicken, and pig). The identification of these genes is an important step toward the goal of increasing meat yields and improves meat quality.

Identification of Genomic Regions for Carcass Quality Traits within the American Simmental Association Carcass Merit Program

USDA quality and yield grade are primary driving forces for carcass value in the United States. Carcass improvements can be achieved by making selection decisions based on the results of genetic evaluations in the form of expected progeny differences (EPD), real-time ultrasound imaging, and physical evaluation of candidate breeding animals. In an effort to advance their ability to accurately predict the breeding value of potential sires for carcass traits, the American Simmental Association launched the Carcass Merit Program as a means to collect progeny sire group carcass information. All records were extracted from the American Simmental Association database. Progeny data were organized by sire family and progeny performance phenotypes were constructed. Sire genotypes were filtered, and a multi-locus mixed linear model was used to perform an association analysis on the genotype data, while correcting for cryptic relatedness and pedigree structure. Three chromosomes were found to have genome-wide significance and this conservative approach identified putative QTL in those regions. Three hundred ninety-three novel regions were identified across all traits, as well as 290 novel positional candidate genes. Correlations between carcass characteristics and maternal traits were less unfavorable than those previously reported.

Association between polymorphisms of Myf5, MSTN and CAST genes and fattening performance in Brown Swiss and Holstein cattle breeds

This study determined the association between Myf5, CAST and MSTN genes and fattening performance traits in 228 (Holstein = 103 and Brown = 125) cattle breeds. Classification and regression tree (CART) was used to determine association between genes and fattening performance. The allele frequencies of Holstein cattle in terms of Myf5, CAST and MSTN genes were A:0.30, B:0.70; A:0.43, G:0.56; A:0.97, B:0.03, respectively, whereas in the Brown Swiss cattle were A:0.36, B:0.64; A:0.65, G:0.34; A:0.88, B:0.12 respectively. The Myf5, CAST, and MSTN genes were found to be in the Hardy-Weinberg equilibrium (p > 0.05) in both of the cattle breeds. As a result, the association between Myf5, CAST and MSTN genes and fattening performance traits were found to be significant according to CART analysis.

Genetic variants in MYF5 affected growth traits and beef quality traits in Chinese Qinchuan cattle

Myogenic factor 5 plays actively roles in the regulation of myogenesis. The aims of this study are to identify the evolution information of MYF5 protein among 10 domestic and mammalian animals, to uncover the expression patterns of MYF5 gene in calves and adults of Qinchuan cattle, and to expose the genetic variants of the MYF5 gene and explore its effect on cattle growth traits and beef quality traits in Qinchuan cattle. The bioinformatics results showed that the MYF5 proteins highly conserved in different mammalian or domestic animals apart from chicken. The expression level of MYF5 gene in the heart, muscle, lung, large intestine and liver was greater than that of other tissues. PCR amplicons sequencing identified four novel SNPs at g.5738A>G, g.5785C>T and g.5816A>G in the 3rd exon region and g.6535A>G in the 3' UTR. Genotypic frequencies of g.5785C>T was harshly deviated from the HWE (P < .05). Genetic diversity was low or intermediate for the four SNPs and those SNPs were in the weak linkage disequilibrium. Association analysis results indicated g.5785C>T, g.5816A>G and g.6535A>G significant effect on growth performance and beef quality traits of Qinchuan cattle. H1H3 diplotype had greater body size and better beef quality. All the results implicate that the MYF5 gene might be applied as a promising candidate gene in Qinchuan cattle breeding.

Expression patterns and genetic variation of the ovine skeletal muscle transcriptome of sheep from five Spanish meat breeds

The goal of the current study is to analyse the gene expression profile of the ovine skeletal muscle as well as to characterize the genetic variation of transcripts expressed in such tissue. This aim has been achieved by sequencing the longissimus dorsi transcriptomes of 50 sheep distributed in five pools representing the Canaria de Pelo, Roja Mallorquina, Gallega, Xisqueta and Ripollesa Spanish autochthonous breeds. Approximately, 363 million reads per pool have been produced and 71.9–82.9% have been successfully mapped to the ovine genome in a paired-end mode (2 × 75 bp). The 200 most expressed muscle transcripts (≈1% of the total transcript count) account for 51% (Canaria de Pelo) to 67% (Gallega) of the total ovine skeletal muscle mRNA expression. These highly expressed genes play key roles in pathways related with striated muscle contraction, gluconeogenesis, glycolysis, citric acid cycle and respiratory electron transport. RNA-Sequencing of muscle transcripts has also revealed that ~72% of the SNPs detected with this approach are shared by at least two pools, and 10% of them segregate in the five pools under analysis. Most of the substitutions detected by RNA-Seq are synonymous or missense and only a minority are predicted to have consequences on protein function.

A comparison of statistical associations between oedema in the lumbar fat on MRI, BMI and Back Fat Thickness (BFT)

Purpose

To compare the relationship between obesity markers Body Mass Index (BMI) and Back Fat Thickness (BFT) and oedema in the lumbo-sacral subcutaneous adipose tissue.

Patients and methods

A retrospective study was performed of consecutive Magnetic Resonance Imaging examinations on 149 adults (95 females and 54 males) scanned at 1.5T between October 1 and December 31, 2010. The extent of oedema was graded from 1 to 8 based on the number of involved anatomical segments on the Fat Sat sequence. A vertebra and the disc immediately inferior or any of the upper, middle or lower third of the sacrum was assigned 1 unit. BFT was measured superiorly at the upper border of L1 (BFT L1) and inferiorly at the lower border of L5 (BFT L5) on the T1 weighted image. BMI was computed at the time of the examination. The data were analysed using StatPlus 2009. The association between variables was evaluated using univariate and multivariate regression.

Results

68 patients (45.6%), 50 females (33.6%) and 18 males (12.0%) were found to have oedema. Weight (p = 0), BMI (p < 0.001), BFT L1 (p < 0.001), BFT L5 (p < 0.001) and age (p = .01) were significantly associated with oedema. On forward stepwise multiple regression significant independent variables predicting oedema were found to be BMI, BFT L1 and Age. ANOVA indicated that BMI explained 23.6% (F = 45.5, p = 0), BFT L1 22.7% (F = 43.2, p = 0) and age 4.7% (F = 7.4, p = 0.007) of the variance of oedema.

Conclusions

Obesity markers BMI and BFT L1 are significant independent variables predicting oedema. Oedema is predicted to a variable extent by fat at different sites. The oedema may be, in part, a consequence of obesity.

Modeling tenderness for genetic and quantitative trait loci analyses

Tenderness is the one of the most important attributes of beef with regards to the intent of consumers to repurchase. Beef tenderness is frequently measured objectively as Warner-Bratzler shear force. However, to better understand the genetics underlying tenderness, better descriptors were derived herein. Two traits, adjusted shear force and aging rate, were calculated to incorporate measures of Warner-Bratzler shear force repeated over aging time of 2 muscles, longissimus dorsi (LD) and semitendinosus (ST). Analysis of these traits indicated that the shear forces of the 2 muscles are lowly correlated and aging rate, as calculated, was not correlated with adjusted shear force. Breed, SNP, and QTL effects were analyzed for the 4 traits (2 traits × 2 muscles). For adjusted shear force, the QTL were located on cattle chromosomes BTA 5, 18, 25, and 29. With the exception of the QTL on BTA 5, the adjusted shear force QTL were observed for either the LD or the ST but not both muscles. The QTL for aging rate were located on BTA 1, 4, 7, 11, 13, 19, and 20.