Fat Deposition In Beef Cattle Research Articles

Transcriptomics and Lipid Metabolomics Analysis of Subcutaneous, Visceral, and Abdominal Adipose Tissues of Beef Cattle.

Fat deposition traits are influenced by genetics and environment, which affect meat quality, growth rate, and energy metabolism of domestic animals. However, at present, the molecular mechanism of fat deposition is not entirely understood in beef cattle. Therefore, the current study conducted transcriptomics and lipid metabolomics analysis of subcutaneous, visceral, and abdominal adipose tissue (SAT, VAT, and AAT) of Huaxi cattle to investigate the differences among these adipose tissues and systematically explore how candidate genes interact with metabolites to affect fat deposition. These results demonstrated that compared with SAT, the gene expression patterns and metabolite contents of VAT and AAT were more consistent. Particularly, SCD expression, monounsaturated fatty acid (MUFA) and triglyceride (TG) content were higher in SAT, whereas PCK1 expression and the contents of saturated fatty acid (SFA), diacylglycerol (DG), and lysoglycerophosphocholine (LPC) were higher in VAT. Notably, in contrast to PCK1, 10 candidates including SCD, ELOVL6, ACACA, and FABP7 were identified to affect fat deposition through positively regulating MUFA and TG, and negatively regulating SFA, DG, and LPC. These findings uncovered novel gene resources and offered a theoretical basis for future investigation of fat deposition in beef cattle.

Integrating genomics and transcriptomics to identify candidate genes for subcutaneous fat deposition in beef cattle

Fat deposition is a complex economic trait regulated by polygenic genetic basis and environmental factors. Therefore, integrating multi-omics data to uncover its internal regulatory mechanism has attracted extensive attention. Here, we performed genomics and transcriptomics analysis to detect candidates affecting subcutaneous fat (SCF) deposition in beef cattle. The association of 770K SNPs with the backfat thickness captured nine significant SNPs within or near 11 genes. Additionally, 13 overlapping genes regarding fat deposition were determined via the analysis of differentially expressed genes and weighted gene co-expression network analysis (WGCNA). We then calculated the correlations of these genes with BFT and constructed their interaction network. Finally, seven biomarkers including ACACA, SCD, FASN, ACOX1, ELOVL5, HACD2, and HSD17B12 were screened. Notably, ACACA, identified by the integration of genomics and transcriptomics, was more likely to exert profound effects on SCF deposition. These findings provided novel insights into the regulation mechanism underlying bovine fat accumulation.

Effects of Vitamin A on Yanbian Yellow Cattle and Their Preadipocytes by Activating AKT/mTOR Signaling Pathway and Intestinal Microflora.

Simple SummaryVitamin A is a fat-soluble vitamin that not only plays a role in vision, growth, and development, but also in fat production and metabolism in animals. To improve the production of high-grade beef, it is necessary to explore the molecular mechanism of intramuscular fat deposition in beef cattle through molecular biology techniques. In this study, we selected Yanbian yellow cattle, one of the five major cattle breeds in China, to investigate the effects of vitamin A and its metabolite, all-trans retinoic acid (ATRA), on the proliferation and differentiation of preadipocytes and changes in intestinal microorganisms. It was found that ATRA inhibited adipogenic differentiation of preadipocytes in Yanbian yellow cattle via the AKT/mTOR signaling pathway. This study provides insight into nutritional management and reveals the role of vitamin A in lipid metabolism in Yanbian yellow cattle.In this study, the effects of vitamin A and its metabolite, all-trans retinoic acid (ATRA), on the proliferation and differentiation of preadipocytes and the intestinal microbiome in Yanbian yellow cattle were investigated. Preadipocytes collected from Yanbian yellow cattle treated with different concentrations of ATRA remained in the G1/G0 phase, as determined by flow cytometry. Quantitative reverse-transcription polymerase chain reaction and western blotting analyses showed that the mRNA and protein expression levels of key adipogenic factors, peroxisome proliferator- activated receptor gamma (PPARγ), CCAAT enhancer-binding protein α (C/EBPα), and extracellular signal-regulated kinase 2 (ERK2), decreased. ATRA was found to regulate the mTOR signaling pathway, which is involved in lipid metabolism, by inhibiting the expression of AKT2 and the adipogenic transcription factors SREBP1, ACC, and FAS; the protein and mRNA expression levels showed consistent trends. In addition, 16S rRNA sequencing results showed that a low concentration of vitamin A promoted the growth of intestinal microflora beneficial to lipid metabolism and maintained intestinal health. The results indicated that ATRA inhibited the adipogenic differentiation of preadipocytes from Yanbian yellow cattle through the AKT/mTOR signaling pathway, and that low concentrations of vitamin A may help maintain the intestinal microbes involved in lipid metabolism in cattle.

Integrating Genomics and Transcriptomics to Identify Candidate Genes for Subcutaneous Fat Deposition in Beef Cattle

Integrating Genomics and Transcriptomics to Identify Candidate Genes for Subcutaneous Fat Deposition in Beef Cattle

C/EBPβ converts bovine fibroblasts to adipocytes without hormone cocktail induction

Adipogenesis and fibrogenesis can be considered as a competitive process in muscle, which may affect the intramuscular fat deposition. The CCAAT/enhancer-binding protein beta (C/EBPβ) plays an important role in adipogenesis, which is well-characterized in mice, but little known in bovine so far. In this study, real-time qPCR revealed that the level of C/EBPβ was increased during the developmental stages of bovine and adipogenesis process of preadipocytes. Overexpression of C/EBPβ promoted bovine fibroblast proliferation through mitotic clonal expansion (MCE), a necessary process for initiating adipogenesis, by significantly downregulating levels of p21 and p27 ( p < 0.01). Also, the PPARγ expression was inhibited during the MCE stage ( p < 0.01). 31.28% of transfected fibroblasts adopted lipid-laden adipocyte morphology after 8 d. Real-time qPCR showed that C/EBPβ activated the transcription of early stage adipogenesis markers C/EBPα and PPARγ . Expression of ACCα , FASN , FABP4 and LPL was also significantly upregulated, while the expression of LEPR was weakened. It was concluded C/EBPβ can convert bovine fibroblasts into adipocytes without hormone induction by initiating the MCE process and promoting adipogenic genes expression, which may provide new insights into the potential functions of C/EBPβ in regulating intramuscular fat deposition in beef cattle. How to cite : Cheng G, Raza SHA, Khan R, et al. C/EBPβ converts bovine fibroblasts to adipocytes without hormone cocktail induction. Electron J Biotechnol 2021;52. https://doi.org/10.1016/j.ejbt.2021.04.008

Proteomic analysis reveals changes in energy metabolism of skeletal muscle in beef cattle supplemented with vitamin A.

Vitamin A has been reported as a factor influencing marbling deposition in meat from animals. Although the mechanisms by which vitamin A regulates lipid metabolism in mature adipocytes are already well-established, information regarding molecular mechanisms underlying the effects of vitamin A on the regulation of intramuscular fat deposition in beef cattle still remains limited. The present study aimed to assess the molecular mechanisms involved in the intramuscular fat deposition in beef cattle supplemented with vitamin A during the fattening phase using a proteomic approach. Vitamin A supplementation during the fattening phase decreased intramuscular fat deposition in beef cattle. Proteome and phospho-proteome analysis together with biological and networking analysis of the protein differentially abundant between treatments indicated that Vitamin A supplementation affects the overall energy metabolism of skeletal muscle, impairing lipid biosynthesis in skeletal muscle. Vitamin A supplementation at fattening phase impairs intramuscular fat deposition in beef cattle likely by changing the energy metabolism of skeletal muscle. The interaction of retinoic acid and heat shock 70-kDa protein may play a pivotal role in intramuscular fat deposition as a consequence of vitamin A supplementation by impairing de novo fatty acid synthesis as a result of a possible decrease in insulin sensitivity in the skeletal muscle. © 2020 Society of Chemical Industry.

349 Relationship between ruminal volatile fatty acids and microbial population with carcass and meat quality traits in beef steers.

Volatile fatty acids (VFAs), the end products of rumen fermentation, are the principal energy source for ruminants which potentially affect carcass yield and fat deposition in beef cattle. Rumen microbiota affects lipid metabolism in ruminants which might contribute to the variation in fat deposition. In this study, rumen fluid samples were collected from 204 beef steers raised under feedlot in Roy Berg Kinsella Research Ranch, University of Alberta. Individual VFA concentrations were measured using gas chromatography, and the bacterial and archaeal abundances were estimated by measuring total copy numbers of their respective 16S rRNA genes using qPCR. Animal phenotypic measures including body weight (BW), dry matter intake (DMI), average daily gain (ADG), hot carcass weight (HCW), age at slaughter (age), ribeye area (CREA), adipose fat thickness (AFAT), lean meat yield (LMY) and marbling score (MS) were collected. The relationships among microbiota, VFAs and carcass traits were evaluated using stepwise, backward linear regression with a significant level of 0.05. The HCW was positively correlated with BW and ADG and was negatively correlated with propionate. Negative correlations were identified between age and BW, RFI, acetate, propionate, and butyrate. CREA had positive correlations with BW and DMI, and negative correlations with acetate. AFAT was positively correlated with DMI, BW and propionate while, acetate and butyrate tentatively positively correlated (P < 0.1) with AFAT. The LMY was negatively correlated with BW, DMI, acetate, propionate and butyrate. Marbling score was positively correlated with DMI, acetate, propionate and butyrate. The relationship between rumen microbial abundance and the above carcass and meat quality-related traits were not detected in this study. Our preliminary results reveal that rumen VFAs may contribute to carcass and meat quality traits in beef cattle, suggesting the potential application to improving carcass and meat quality in beef steers through manipulating rumen VFA.

Genetic, management, and nutritional factors affecting intramuscular fat deposition in beef cattle - A review.

Intramuscular fat (IMF) content in skeletal muscle including the longissimus dorsi muscle (LM), also known as marbling fat, is one of the most important factors determining beef quality in several countries including Korea, Japan, Australia, and the United States. Genetics and breed, management, and nutrition affect IMF deposition. Japanese Black cattle breed has the highest IMF content in the world, and Korean cattle (also called Hanwoo) the second highest. Here, we review results of research on genetic factors (breed and sex differences and heritability) that affect IMF deposition. Cattle management factors are also important for IMF deposition. Castration of bulls increases IMF deposition in most cattle breeds. The effects of several management factors, including weaning age, castration, slaughter weight and age, and environmental conditions on IMF deposition are also reviewed. Nutritional factors, including fat metabolism, digestion and absorption of feed, glucose/starch availability, and vitamin A, D, and C levels are important for IMF deposition. Manipulating IMF deposition through developmental programming via metabolic imprinting is a recently proposed nutritional method to change potential IMF deposition during the fetal and neonatal periods in rodents and domestic animals. Application of fetal nutritional programming to increase IMF deposition of progeny in later life is reviewed. The coordination of several factors affects IMF deposition. Thus, a combination of several strategies may be needed to manipulate IMF deposition, depending on the consumer’s beef preference. In particular, stage-specific feeding programs with concentrate-based diets developed by Japan and Korea are described in this article.

Integrative analysis of microRNAs and mRNAs revealed regulation of composition and metabolism in Nelore cattle

BackgroundThe amount of intramuscular fat can influence the sensory characteristics and nutritional value of beef, thus the selection of animals with adequate fat deposition is important to the consumer. There is growing knowledge about the genes and pathways that control the biological processes involved in fat deposition in muscle. MicroRNAs (miRNAs) belong to a well-conserved class of non-coding small RNAs that modulate gene expression across a range of biological functions in animal development and physiology. The aim of this study was to identify differentially expressed (DE) miRNAs, regulatory candidate genes and co-expression networks related to intramuscular fat (IMF) deposition. To achieve this, we used mRNA and miRNA expression data from the Longissimus dorsi muscle of 30 Nelore steers with high (H) and low (L) genomic estimated breeding values (GEBV) for IMF deposition.ResultsDifferential miRNA expression analysis between animals with extreme GEBV values for IMF identified six DE miRNAs (FDR 10%). Functional annotation of the target genes for these microRNAs indicated that the PPARs signaling pathway is involved with IMF deposition. Candidate regulatory genes such as SDHAF4, FBXO17, ALDOA and PKM were identified by partial correlation with information theory (PCIT), phenotypic impact factor (PIF) and regulatory impact factor (RIF) co-expression approaches from integrated miRNA-mRNA expression data. Two DE miRNAs (FDR 10%), bta-miR-143 and bta-miR-146b, which were upregulated in the Low IMF group, were correlated with regulatory candidate genes, which were functionally enriched for fatty acid oxidation GO terms. Co-expression patterns obtained by weighted correlation network analysis (WGCNA), which showed possible interaction and regulation between mRNAs and miRNAs, identified several modules related to immune system function, protein metabolism, energy metabolism and glucose catabolism according to in silico analysis performed herein.ConclusionIn this study, several genes and miRNAs were identified as candidate regulators of IMF by analyzing DE miRNAs using two different miRNA-mRNA co-expression network methods. This study contributes to the understanding of potential regulatory mechanisms of gene signaling networks involved in fat deposition processes measured in muscle. Glucose metabolism and inflammation processes were the main pathways found in silico to influence intramuscular fat deposition in beef cattle in the integrative mRNA-miRNA co-expression analysis.

A single nucleotide polymorphism possibly associated with fat deposition is methylated in the bovine TFAM promoter

Mitochondrial transcription factor A (TFAM) is a nuclear-encoded mitochondrial protein that plays an important role in energy metabolism and is a candidate gene for fat deposition in cattle and human. In the present study, we characterized the methylation status of bovine TFAM promoter flanking the single nucleotide polymorphism (SNP) rs42159487C&gt;T, previously reported to affect fat deposition. Our results showed that the cytosine at this SNP position is methylated and therefore results in gain/loss of the functional CpG locus (5mC&gt;T). Promoter constructs developed based on three TFAM SNPs showed that the C/C/C haplotype associated with fat deposition in beef cattle had lower promoter function/activity than A/T/T haplotype. Our results imply that genetic variability underlying gain/loss of the CpG sites in the nuclear-encoded mitochondrial proteins might be good candidate loci for fat deposition phenotypes.

Effect of β-carotene supplementation on the expression of lipid metabolism-related genes and the deposition of back fat in beef cattle

To evaluate the effects of β-carotene (βC) supplementation on lipid metabolism in the back fat of beef cattle, 120 continental crossbred (Simmental × local Luxi yellow cattle) steers were selected randomly from feedlots and allotted to four groups. Each steer was supplemented with 0, 600, 1200, or 1800 mg/day of βC for 90 days, and then received no βC for 60 days (depletion period). The βC levels significantly increased in steers supplemented with βC (P &lt; 0.01), and then decreased to the control level by Day 150. Back fat thickness decreased slightly with increasing βC supplementation, and significantly differed among groups after supplementation ceased (P &lt; 0.01 on Day 120, P &lt; 0.05 on Day 150). Significant regression relationships between βC supplement level and both βC content in back fat tissue on Day 90 and back fat thickness on Days 90, 120, and 150 were established (P &lt; 0.01). No significant differences in the dry matter intake or average daily gain were detected, but higher net meat percentages were observed in the 1200 and 1800 mg/day βC-supplemented groups compared with the control (P &lt; 0.05). The mRNA expression of two fat synthesis-related genes, acetyl-CoA carboxylase and fatty acid synthase, were downregulated during the supplementation period, but upregulated during the next 60 days when the steers received no βC supplementation. In contrast, the expression of two fat hydrolysis-related genes, hormone-sensitive lipase and adipose triglyceride lipase, were upregulated during the supplementation period and downregulated in the subsequent 60 days. The results showed that βC supplementation suppresses back fat deposition in beef cattle by inhibiting fat synthesis and enhancing fat hydrolysis.

Association between Single Nucleotide Polymorphisms in the Dgat2 Gene and Beef Carcass and Quality Traits in Commercial Feedlot Steers

Diacylglycerol acyltransferase (DGAT) is a key enzyme that catalyzes the final and rate-limiting step of triglyceride synthesis. Both DGAT1 and DGAT2 genes code proteins with DGAT activity. Studies have shown DGAT1 polymorphisms associate with intramuscular fat deposition in beef cattle, but fewer associations between DGAT2 and beef cattle economic traits have been reported. The objective of this study was to investigate single nucleotide polymorphism (SNP) in intron3 of bovine DGAT2 and evaluate the associations of that with carcass, meat quality, and fat yield traits. Test animals were 157 commercial feedlot steers belonging to 3 Chinese native breeds (22 for Luxi, 24 for Jinnan, and 23 for Qinchuan), 3 cross populations (20 for CharolaisxFuzhou, 18 for Limousin xLuxi, and 17 for Simmental×Jinan) and 1 Taurus pure breed population (16 Angus steers). In the current study, 15 SNP were discovered in intron3 and exon4 of DGAT2 at positions 65, 128, 178, 210, 241, 255, 270, 312, 328, 334, 365, 366, 371, 415, and 437 (named as their positions in PCR amplified fragments). Only 7 of them (128, 178, 241, 270, 312, 328, and 371) were analyzed, because SNP in three groups (65-128-255, 178-210-365 and 241-334-366) were in complete linkage disequilibrium within the group, and SNP 415 was a deletion and 437 was a null mutation. Frequencies for rare alleles in the 3 native breed populations were higher than in the 3 cross populations for 178 (p = 0.04), 270 (p = 0.001), 312 (p = 0.03) and 371 (p = 0.002). A general linear model was used to evaluate the associations between either SNP genotypes or allele substitutions and the measured traits. Results showed that SNP 270 had a significant association with the fat yield associated with kidney, pelvic cavity, heart, intestine, and stomach (KPHISY). Animals with genotype CC and CT for 270 had less (CC: -7.71±3.3 kg and CT: -5.34±2.5 kg) KPHISY than animals with genotype TT (p = 0.02). Allele C for 270 was associated with an increase of -4.26±1.52 kg KPHISY (p = 0.006) and -0.92±0.45% of retail cuts weight percentage (NMP, Retail cuts weight/slaughter body weight) (p = 0.045); allele G for 312 was associated with an increase of -5.45±2.41 kg KPHISY (p = 0.026). An initial conclusion was that associations do exist between DGAT2 gene and carcass fat traits. Because of the small sample size of this study, it is proposed that further effort is required to validate these findings in larger populations.

Hot Topic: An Association Between a Leptin Single Nucleotide Polymorphism and Milk and Protein Yield

Allelic variation (C to T transition that results in an Arg25Cys) in the leptin gene has been associated with increased fat deposition in beef cattle. We report that this same genetic variant is also present in dairy breeds. Body fat reserves play an important role in sustaining high milk production in early lactation, when energy intake is limited. To test for an association between the leptin single nucleotide polymorphism and milk productivity, we genotyped 416 Holstein cows and compared lactation performance data using a mixed model. Animals homozygous for the T allele produced more milk (1.5kg/d vs. CC animals) and had higher somatic cell count linear scores, without significantly affecting milk fat or protein percent over the entire lactation. The increase in milk yield is most prominent in the first 100 d of lactation (2.44kg/d), declining to 1.74kg/d between 101 and 200 d in lactation. The milk yield advantage, observed in cows homozygous for the T allele, could represent a major economic advantage to dairy producers.

Relationship of fatty acid composition to intramuscular fat content in beef from crossbred Wagyu cattle.

The deposition of i.m. fat, or marbling, in cattle is recognized as a desirable carcass trait in North American beef grading schemes. In order to investigate the relationship between degree of marbling and fatty acid composition of whole bovine muscle, we extracted the total lipid from pars costalis diaphragmatis (PCD) (n = 23) and longissimus (n = 36) muscles from Wagyu crossbred cattle that were assigned Canadian Grading Agency marbling scores ranging from 1 to 8 on an inverse 10-point scale (i.e., a score of 1 indicated "very abundant" marbling and a score of 10 would be assigned to a carcass "devoid" of marbling). Fatty acid methyl esters (FAME) of the total lipid and triacylglycerol fractions were resolved and quantified through GLC. Marbling scores were negatively associated with total lipid from both PCD (r = -.57, P < .01) and longissimus (r = -.80, P < .001). Differences between PCD and longissimus were found for almost all FAME studied from both lipid fractions, but no differences (P > .05) were seen when the monounsaturated:saturated fatty acid (MUFA/SFA) ratios were compared. Heifers had higher (P < .05) oleic acid content and lower (P < .05) palmitic acid content in lipid extracted from both muscles, resulting in higher (P < .05) MUFA/SFA ratios than those for steers. The relative amount of myristic acid increased as the lipid content (total lipid and triacylglycerol) increased in either longissimus (r values from .48 to .55; n = 36; P < .01) or PCD muscles (r from .67 to .76; n = 23; P < .001). The relative amount of linoleic acid (cis-9, cis-12 isomer) from total lipid was negatively associated with all chemical measurements of lipid from the longissimus (r from -.52 to -.64; n = 36; P < .001) and PCD muscles (r from -.75 to -.85; n = 23; P < .001). This association was not significant (P > .1) for either muscle when linoleic acid from the triacylglycerol fraction was examined, suggesting the negative association between this fatty acid and lipid content was due to a dilution of membrane phospholipids with increasing triacylglycerol. Indices of fatty acid elongase activity, calculated from FAME data, implicated the balance between this enzyme activity and fatty acid synthase as a source of variation between animals displaying various degrees of marbling and worthy of further investigation to better understand the process of marbling fat deposition in beef cattle.

A potential association between the BM 1500 microsatellite and fat deposition in beef cattle.

The obese gene was hypothesized as a candidate gene for fat characteristics in beef cattle. The BM 1500 microsatellite, near the obese gene, was characterized in 158 purebred beef bulls for which carcass trait information was available. Four breeds were included in the analyses-Angus, Charolais, Hereford, and Simmental. Four alleles were found. Lengths were approximately 138, 147, 149, and 140 bp with genotypic frequencies of 0.47, 0.44, 0.09, and 0.003 respectively. The carcass traits %rib fat, %rib lean, average fat, and grade fat were found to be significantly associated with the different alleles. The presence of the 138-bp allele in the genotype of an animal is correlated with higher levels of fat, whereas the 147-bp allele has the opposite effect. The 149-bp allele was found in low numbers, and a homozygote was never identified. Hereford and Angus bulls had the greatest frequencies of 138-bp alleles (Hereford = 0.57, Angus = 0.59), while Charolais and Simmental had a greater proportion of 147-bp alleles (Charolais = 0.54, Simmental = 0.58). This information may aid cattle producers in selecting cattle for markets that differ in the amount of fat required.

Effect of forage:concentrate ratio in the diet on concentrations of IGF-1, insulin, glucagon and volatile fatty acids appearing across the splanchnic tissues of steers

Steen (1992) demonstrated that grass silage diets sustained lower carcass lean gain per MJ digestible energy (DE) intake than diets of low forage: concentrate ratios (F:CR), at equal levels of DE intake. Jugular concentrations of IGF-1, insulin and glucagon were significantly elevated in animals offered the latter diets while rumen VFA were unaffected (Thorp et al1994). Both IGF-1 and insulin stimulate protein synthesis (Abdul-Razzaq and Bickerstaffe 1989, Douglas et al1991) and it is generally accepted that insulin and glucagon influence carbohydrate metabolism in the ruminant. Plasma propionate and butyrate stimulate insulin and glucagon secretion (Harmon 1991). This experiment was part of a series designed to investigate the control of lean and fat deposition in beef cattle and aimed to determine concentrations of IGF-1, insulin, glucagon and VFA appearing across the splanchnic tissues.

Effect of forage:concentrate ratio in the diet on concentrations of IGF-1, insulin, glucagon and volatile fatty acids appearing across the splanchnic tissues of steers

Steen (1992) demonstrated that grass silage diets sustained lower carcass lean gain per MJ digestible energy (DE) intake than diets of low forage: concentrate ratios (F:CR), at equal levels of DE intake. Jugular concentrations of IGF-1, insulin and glucagon were significantly elevated in animals offered the latter diets while rumen VFA were unaffected (Thorp et al1994). Both IGF-1 and insulin stimulate protein synthesis (Abdul-Razzaq and Bickerstaffe 1989, Douglas et al1991) and it is generally accepted that insulin and glucagon influence carbohydrate metabolism in the ruminant. Plasma propionate and butyrate stimulate insulin and glucagon secretion (Harmon 1991). This experiment was part of a series designed to investigate the control of lean and fat deposition in beef cattle and aimed to determine concentrations of IGF-1, insulin, glucagon and VFA appearing across the splanchnic tissues.