Association of μ-Calpain and Calpastatin Polymorphisms with Meat Tenderness in a Brahman-Angus Population

Genome-wide scans identify biological and metabolic pathways regulating carcass and meat quality traits in beef cattle

Genome association studies (GWAS) provides knowledge about the genetic architecture of beef-related traits that allow linking the target phenotype to genomic information aiding breeding decision. Thus, the present study aims to uncover the genetic mechanism involved in carcass (REA: rib eye area, BF: backfat thickness, and HCW: hot carcass weight) and meat quality traits (SF: shear-force, MARB: marbling score, and IMF: intramuscular fat content) in Nellore cattle. For this, 6910 young bulls with phenotypic information and 23,859 animals genotyped with 435 k markers were used to perform the weighted single-step GBLUP (WssGBLUP) approach, considering two iterations. The top 10 genomic regions explained 8.13, 11.81, and 9.58% of the additive genetic variance, harboring a total of 119, 143, and 95 positional candidate genes for REA, BF, and HCW, respectively. For meat quality traits, the top 10 windows explained a large proportion of the total genetic variance for SF (14.95%), MARB (17.56%), and IMF (21.41%) surrounding 92, 155, and 111 candidate genes, respectively. Relevant candidate genes (CAST, PLAG1, XKR4, PLAGL2, AQP3/AQP7, MYLK2, WWOX, CARTPT, and PLA2G16) are related to physiological aspects affecting growth, carcass, meat quality, feed intake, and reproductive traits by signaling pathways controlling muscle control, key signal metabolic molecules INS / IGF-1 pathway, lipid metabolism, and adipose tissue development. The GWAS results provided insights into the genetic control of the traits studied and the genes found are potential candidates to be used in the improvement of carcass and meat quality traits.

Connecting Heat Tolerance and Tenderness in Bos indicus Influenced Cattle

Bos indicus cattle are widely utilized in tropical and subtropical climates. Their heat tolerance and parasite resistance are integral for beef production in these regions; however, a reputation for excitable temperaments, slower growth, and variation in tenderness has limited their use in commercial beef production. This suggests that there is antagonism between heat tolerance and meat production traits. Meat quality characteristics are determined by the properties of skeletal muscle as well as conditions during slaughter and processing. Thus, it is possible that adaptations related to heat tolerance in the living animal affect tenderness and other meat quality attributes. Since muscle represents a large proportion of body mass, relatively small changes at the cellular level could impact overall heat production of the animal. Specifically, protein degradation and mitochondria function are aspects of organ and cellular metabolism that may help limit heat production and also have a connection to tenderness. Protein degradation postmortem is critical to structural changes that enhance tenderness whereas mitochondria may influence tenderness through their roles in energy metabolism, calcium regulation, cell death signaling, and oxidative stress. This review explores potential relationships between cellular metabolism in vivo and beef quality development in Bos indicus and Bos indicus influenced cattle.

Identification of Meat Quality Determining Marker Genes in Fibroblasts of Bovine Muscle Using Transcriptomic Profiling

In the present study, we comparatively analyzed the transcriptomic profiling of fibroblasts derived from two different muscles, biceps femoris and longissimus dorsi with significant difference in the meat quality and tenderness. EBSeq algorithm was applied to analyze the data, and genes were considered to be significantly differentially expressed if the false discovery rate value was <0.05, the P value was <0.01, and the fold change was >0.585. The results revealed that 253 genes were differentially expressed genes (DEGs) (170 genes were upregulated, and 83 were downregulated) and more than 100 DEGs were probably associated with intramuscular fat deposition, tenderness, and toughness, which are driving the meat quality and were involved in biological processes such as collagen synthesis, cell differentiation, and muscle tissue and fiber development; molecular functions such as chemokine activity and collagen activity; cellular components such as cytoplasm and myofibril; and pathways such as collagen signaling and metabolic pathways. A gene-act network and a co-expression network revealed the close relationship between intramuscular fat deposition and meat tenderness. The expressions of 20 DEGs were validated by real-time PCR, and the results suggested that the DEGs are correlated with RNA-seq data and play crucial roles in muscle growth, development processes, toughness, and tenderness of the meat. Together, the genome-wide transcriptome analysis revealed that various genes are responsible for toughness and tenderness variance in the difference muscles of beef.

Calpastatin (CAST) Gene Polymorphism in Tsigai and Merinoland Sheep Breeds Under Conditions of the Republic of Crimea

The article presents the results of studying the Calpastatin (CAST) gene polymorphism in Tsigai (n = 23) and Merinoland sheep breed (n = 13). The purpose of the research. The possibility of using PCR-RFLP analysis to detect the Calpastatin (CAST) gene polymorphism in Tsigai and Merinoland sheep was the primary objective of this ongoing study. Research methods. Calpastatin (CAST) gene polymorphism was analyzed by PCR-RFLP analysis using the MspI endonuclease restriction. Results. We revealed the diversity of genotypes and allelic variants of the Calpastatin (CAST) gene in Tsigai and Merinoland Breeds. It was found that M allele of the Calpastatin locus is the most common. Frequencies of MM, MN and NN genotypes were found to be 74, 4 and 22 % in Tsigai breed. Among the representatives of Merinoland sheep, the frequencies of MM and MN genotypes were 92 % and 8%, respectively. No animals with NN genotypes were found.

RNA-seq analysis identifies cytoskeletal structural genes and pathways for meat quality in beef

RNA sequencing (RNA-seq) has allowed for transcriptional profiling of biological systems through the identification of differentially expressed (DE) genes and pathways. A total of 80 steers with extreme phenotypes were selected from the University of Florida multibreed Angus-Brahman herd. The average slaughter age was 12.91±8.69 months. Tenderness, juiciness and connective tissue assessed by sensory panel, along with marbling, Warner-Bratzler Shear Force (WBSF) and cooking loss, were measured in longissimus dorsi muscle. Total RNA was extracted from muscle and one RNA-seq library per sample was constructed, multiplexed, and sequenced based on protocols by Illumina HiSeq-3000 platform to generate 2×101 bp paired-end reads. The overall read mapping rate using the Btau_4.6.1 reference genome was 63%. A total of 8,799 genes were analyzed using two different methodologies, an expression association and a DE analysis. A gene and exon expression association analysis was carried out using a meat quality index on all 80 samples as a continuous response variable. The expression of 208 genes and 3,280 exons from 1,565 genes was associated with the meat quality index (p-value ≤ 0.05). A gene and isoform DE evaluation was performed analyzing two groups with extreme WBSF, tenderness and marbling. A total of 676 (adjusted p-value≤0.05), 70 (adjusted p-value≤0.1) and 198 (adjusted p-value≤0.1) genes were DE for WBSF, tenderness and marbling, respectively. A total of 106 isoforms from 98 genes for WBSF, 13 isoforms from 13 genes for tenderness and 43 isoforms from 42 genes for marbling (FDR≤0.1) were DE. Cytoskeletal and transmembrane anchoring genes and pathways were identified in the expression association, DE and the gene enrichment analyses; these proteins can have a direct effect on meat quality. Cytoskeletal proteins and transmembrane anchoring molecules can influence meat quality by allowing cytoskeletal interaction with myocyte and organelle membranes, contributing to cytoskeletal structure and architecture maintenance postmortem.

Whole Genome Sequence Data Provides Novel Insights Into the Genetic Architecture of Meat Quality Traits in Beef

Tenderness is a major quality attribute for fresh beef steaks in the United States, and meat quality traits in general are suitable candidates for genomic research. The objectives of the present analysis were to (1) perform genome-wide association (GWA) analysis for marbling, Warner-Bratzler shear force (WBSF), tenderness, and connective tissue using whole-genome data in an Angus population, (2) identify enriched pathways in each GWA analysis; (3) construct a protein-protein interaction network using the associated genes and (4) perform a μ-calpain proteolysis assessment for associated structural proteins. An Angus-sired population of 2,285 individuals was assessed. Animals were transported to a commercial packing plant and harvested at an average age of 457 ± 46 days. After 48 h postmortem, marbling was recorded by graders' visual appraisal. Two 2.54-cm steaks were sampled from each muscle for recording of WBSF, and tenderness, and connective tissue by a sensory panel. The relevance of additive effects on marbling, WBSF, tenderness, and connective tissue was evaluated on a genome-wide scale using a two-step mixed model-based approach in single-trait analysis. A tissue-restricted gene enrichment was performed for each GWA where all polymorphisms with an association p-value lower than 1 × 10-3 were included. The genes identified as associated were included in a protein-protein interaction network and a candidate structural protein assessment of proteolysis analyses. A total of 1,867, 3,181, 3,926, and 3,678 polymorphisms were significantly associated with marbling, WBSF, tenderness, and connective tissue, respectively. The associate region on BTA29 (36,432,655-44,313,046 bp) harbors 13 highly significant markers for meat quality traits. Enrichment for the GO term GO:0005634 (Nucleus), which includes transcription factors, was evident. The final protein-protein network included 431 interations between 349 genes. The 42 most important genes based on significance that encode structural proteins were included in a proteolysis analysis, and 81% of these proteins were potential μ-Calpain substrates. Overall, this comprehensive study unraveled genetic variants, genes and mechanisms of action responsible for the variation in meat quality traits. Our findings can provide opportunities for improving meat quality in beef cattle via marker-assisted selection.

Effects of marbling on physical and sensory characteristics of ribeye steaks from four different cattle breeds

OBJECTIVE

Marbling or intramuscular fat (IMF) has been widely reported to directly impact the sensory acceptance of meat. This study was carried out to determine the physical and sensory characteristics of ribeye, Longissimus dorsi steaks obtained from four different cattle breeds namely Wagyu, Angus, Brahman, and Malaysian local beef, the Kedah-Kelantan (KK).

METHODS

The degree of marbling was determined by using an established combined camera-image analysis technique while instrumental texture determination was carried out by using Warner-Bratzler shear force analysis. Sensory evaluation of the beef steaks was performed following a quantitative descriptive analysis incorporating 10 trained consumer panelists.

RESULTS

Wagyu was found to possess the highest (p<0.05) percentage of IMF at 33.90% and the lowest shear force (raw = 5.61 N/mm2; cooked = 14.72 N/mm2) followed by Angus (20.87%), Brahman (12.17%), and KK (p<0.05, 6.86%). The difference in sensory properties of the four steaks was evident, with Wagyu appearing to be highly correlated with most sensory attributes measured namely sustained buttery, tooth-packing, chewiness, juiciness, tenderness, mouthfeel, oiliness, and overall acceptability. The Malaysian local beef, KK was found to be less acceptable (p<0.05), although most of its sensory attributes were found similar (p>0.05) in appearance, aroma, texture, juiciness, and flavour to the cooked steak from Angus and Brahman.

CONCLUSION

This present study demonstrated the role of IMF in determining the quality and sensory acceptance of beef from different cattle breeds. These data have provided new information and further understanding on the physical and sensory quality of Malaysian local beef.

Single Loci and Haplotypes in CAPN1 and CAST Genes are Associated with Growth, Biometrics, and in Vivo Carcass Traits in Santa Inês Sheep

µ-calpain (CAPN1) and calpastatin (CAST) genes play key roles in protein turnover. The present study aimed to identify the variants in these genes associated with growth and ultrasound carcass traits in Santa Inês sheep. A sample of 192 no full sibling Santa Inês lambs was used. Fragments of the CAST and CAPN1 genes were amplified and next-generation sequencing was performed in the MiSeq platform. Variants in the CAPN1 and CAST sequences were then detected using bioinformatic tools. Withers and croup heights, body length, thoracic and croup widths, thoracic and leg girths, body depth, carcass fat score, rib eye area, fat thickness, body weights were recorded at weaning and at 140 days post-weaning, and average daily gain post-weaning was calculated. Both single-locus and haplotype association analyses were performed with the model as follows: farm (2 levels), year (4 levels), the month of birth (12 levels), and the covariate age of the animal. The fragments amplified included 4,514 bp between the 20th and 23rd exons of CAST as well as 3,927 bp between the 12th and 21st exons of CAPN1. In these regions, 58 (CAST) and 45 (CAPN1) variants were identified. In the CAST gene, the single-locus analysis revealed 22 suggestive additive effects (P<0.05) on several growth and carcass traits. Moreover, haplotype substitutions were associated with rib eye area (–0.689±0.290), average daily gain (–23.6±10.4), thoracic girth (–2.72±1.27), body length (–3.38±1.49), and leg girth (–2.84±1.37). Regarding the CAPN1 gene, the single-locus analysis identified seven suggestive additive effects, while only one haplotype replacement effect on fat thickness (–0.0143±0.0053) was detected. The results of the present study suggest that variants in the CAPN1 and CAST genes are associated with growth and ultrasound carcass traits in Santa Inês sheep, which may be a source of information to improve knowledge regarding the genetic control of these traits.

Association of CAST gene polymorphism with carcass value and meat quality in two synthetic lines of sheep

The aim of study was to estimate genotype frequencies of the polymorphism in the intron 12 of CAST gene of growing lambs, and to evaluate associations between the CAST genotype and carcass and meat traits. A total number of 317 rams representing the synthetic BCP (163) and SCP (154) meaty lines were genotyped by the RFLP/MspI/NcoI/Hin6I. Three genotypes including "aa", "ae" and "ac" with most frequencies of 0.48, 0.27 and 0.19, were observed in whole population. Lambs with the "aa" CAST genotype showed the highest muscle percentage and the lowest fat percentage in the hind legs. On the other hand, the loins of rams with "ac" genotype had the highest intramuscular fat content, indicative of beneficial health-related properties and technological usefulness. However, differences between CAST genotype stated for the sensory properties, texture and thawing and cooking losses of the meat were insignificant. Breeding efforts aimed at the improvement of lamb meat quality should prioritize the selection of the "ac" genotype.

Genome wide association and gene enrichment analysis reveal membrane anchoring and structural proteins associated with meat quality in beef

BACKGROUND

Meat quality related phenotypes are difficult and expensive to measure and predict but are ideal candidates for genomic selection if genetic markers that account for a worthwhile proportion of the phenotypic variation can be identified. The objectives of this study were: 1) to perform genome wide association analyses for Warner-Bratzler Shear Force (WBSF), marbling, cooking loss, tenderness, juiciness, connective tissue and flavor; 2) to determine enriched pathways present in each genome wide association analysis; and 3) to identify potential candidate genes with multiple quantitative trait loci (QTL) associated with meat quality.

RESULTS

The WBSF, marbling and cooking loss traits were measured in longissimus dorsi muscle from 672 steers. Out of these, 495 animals were used to measure tenderness, juiciness, connective tissue and flavor by a sensory panel. All animals were genotyped for 221,077 markers and included in a genome wide association analysis. A total number of 68 genomic regions covering 52 genes were identified using the whole genome association approach; 48% of these genes encode transmembrane proteins or membrane associated molecules. Two enrichment analysis were performed: a tissue restricted gene enrichment applying a correlation analysis between raw associated single nucleotide polymorphisms (SNPs) by trait, and a functional classification analysis performed using the DAVID Bioinformatic Resources 6.8 server. The tissue restricted gene enrichment approach identified eleven pathways including "Endoplasmic reticulum membrane" that influenced multiple traits simultaneously. The DAVID functional classification analysis uncovered eleven clusters related to transmembrane or structural proteins. A gene network was constructed where the number of raw associated uncorrelated SNPs for each gene across all traits was used as a weight. A multiple SNP association analysis was performed for the top five most connected genes in the gene-trait network. The gene network identified the EVC2, ANXA10 and PKHD1 genes as potentially harboring multiple QTLs. Polymorphisms identified in structural proteins can modulate two different processes with direct effect on meat quality: in vivo myocyte cytoskeletal organization and postmortem proteolysis.

CONCLUSION

The main result from the present analysis is the uncovering of several candidate genes associated with meat quality that have structural function in the skeletal muscle.

Structural Equation Modeling and Whole-Genome Scans Uncover Chromosome Regions and Enriched Pathways for Carcass and Meat Quality in Beef

Structural equation models involving latent variables are useful tools for formulating hypothesized models defined by theoretical variables and causal links between these variables. The objectives of this study were: (1) to identify latent variables underlying carcass and meat quality traits and (2) to perform whole-genome scans for these latent variables in order to identify genomic regions and individual genes with both direct and indirect effects. A total of 726 steers from an Angus-Brahman multibreed population with records for 22 phenotypes were used. A total of 480 animals were genotyped with the GGP Bovine F-250. The single-step genomic best linear unbiased prediction method was used to estimate the amount of genetic variance explained for each latent variable by chromosome regions of 20 adjacent SNP-windows across the genome. Three types of genetic effects were considered: (1) direct effects on a single latent phenotype; (2) direct effects on two latent phenotypes simultaneously; and (3) indirect effects. The final structural model included carcass quality as an independent latent variable and meat quality as a dependent latent variable. Carcass quality was defined by quality grade, fat over the ribeye and marbling, while the meat quality was described by juiciness, tenderness and connective tissue, all of them measured through a taste panel. From 571 associated genomic regions (643 genes), each one explaining at least 0.05% of the additive variance, 159 regions (179 genes) were associated with carcass quality, 106 regions (114 genes) were associated with both carcass and meat quality, 242 regions (266 genes) were associated with meat quality, and 64 regions (84 genes) were associated with carcass quality, having an indirect effect on meat quality. Three biological mechanisms emerged from these findings: postmortem proteolysis of structural proteins and cellular compartmentalization, cellular proliferation and differentiation of adipocytes, and fat deposition.