Intramuscular Fat Groups Research Articles

Investigation into Critical Gut Microbes Influencing Intramuscular Fat Deposition in Min Pigs.

To determine the pivotal microorganisms affecting intramuscular fat (IMF) accumulation in Min pigs and to discern the extent of the influence exerted by various intestinal segments on IMF-related traits, we sequenced 16S rRNA from the contents of six intestinal segments from a high IMF group (Group H) and a low IMF group (Group L) of Min pigs weighing 90 ± 1 kg. We then compared their diversity and disparities in bacterial genera. Group H exhibited considerably higher α diversity in the jejunum and colon than Group L (p < 0.05). When 95% confidence levels were considered, the main β diversity components for the ileum, caecum, and colon within Groups H and L exhibited absolute segregation. Accordingly, 31 differentially abundant genera across Group H were pinpointed via LEfSe and the Wilcoxon test (p < 0.05) and subsequently scrutinised based on their distribution and abundance across distinct intestinal segments and their correlation with IMF phenotypes. The abundances of Terrisporobacter, Acetitomaculum, Bacteroides, Fibrobacter, Treponema, Akkermansia, Blautia, Clostridium sensu stricto 1, Turicibacter, Subdoligranulum, the [Eubacterium] siraeum group, and dgA 11 gut groups were positively correlated with IMF content (p < 0.05), whereas those of Bacillus, the Lachnospiraceae NK4A136 group, Streptococcus, Roseburia, Solobacterium, Veillonella, Lactobacillus, the Rikenellaceae RC9 gut group, Anaerovibrio, and the Lachnospiraceae AC2044 group were negatively associated with IMF content (p < 0.05). Employing PICRUSt2 for predicting intergenic metabolic pathways that differ among intestinal microbial communities revealed that within the 95% confidence interval the colonic microbiome was enriched with the most metabolic pathways, including those related to lipid metabolism. The diversity results, bacterial genus distributions, and metabolic pathway disparities revealed the colonic segment as an influential region for IMF deposition.

Quality of muscle in the thigh predicts the prognosis in patients with non-ischemic cardiomyopathy

Abstract Background Skeletal muscle atrophy is an independent prognostic predictor for patients with chronic heart failure, and the concept of sarcopenia has garnered scientific attention. Furthermore, the importance of not only muscle mass but also quality of muscle has been pointed out. And a sarcopenia diagnosis is confirmed by the presence of low quality of muscle. However, there is a lack of consensus on the implications of ectopic fat as a quality of muscle for the prognosis in patients with non-ischemic cardiomyopathy. Purpose We investigated whether intramuscular fat (IMF) in the thigh affects the prognosis in patients with non-ischemic cardiomyopathy. Methods We recruited 250 patients who were diagnosed with non-ischemic cardiomyopathy by cardiac catheterization and echocardiographic date between September 2017 and November 2022. Finally, 223 patients enrolled in this prospective study conducted at a single center. Functional status was evaluated by using cardiopulmonary exercise test at baseline. All patients were measured quantity of the percentage of IMF (%IMF) in the thigh using computed tomography scan. Demographic, laboratory and echocardiographic date were collected from the patients’ medical records. Patients were followed up for up to 3 years. Clinical endpoints were cardiovascular death or unexpected rehospitalization because of cardiac events. Results During the follow-up 58 patients had cardiac events. The %IMF was significantly higher in the group with adverse events than without (4.49 ± 4.21 and 3.06 ± 2.39%, respectively; p = 0.001). Spearman correlation coefficient analysis showed a modest correlation between %IMF and exercise tolerance such as anaerobic threshold (Spearman r = -0.367; p &amp;lt; 0.001) and peak oxygen uptake (Spearman r = -0.382; p &amp;lt; 0.001). Patients were divided into 2 groups according to the median values of %IMF. Kaplan-Meier analysis demonstrated that events were significantly higher in the high %IMF group (log-rank p = 0.008). Furthermore, subgroup with left ventricular ejection fraction ≦ 40% or BMI ≧ 22 had a significantly greater frequency of adverse events in the high %IMF group. However, there was no significant difference in %IMF between the groups when divided into two groups at the mean age of this study. Multivariate Cox regression analysis adjusted for left ventricular ejection fraction, estimated glomerular filtration rate, hemoglobin and body mass index found %IMF as an independent factor of adverse events (hazard ratio 1.088; 95% confidential interval 1.024-1.156; p = 0.007). Conclusions In patients with non-ischemic cardiomyopathy, quality of muscle represented by %IMF in the thigh is an independent factor for predicting adverse cardiac events.

Whole-Transcriptome Analysis Sheds Light on the Biological Contexts of Intramuscular Fat Deposition in Ningxiang Pigs.

The quality of pork is significantly impacted by intramuscular fat (IMF). However, the regulatory mechanism of IMF depositions remains unclear. We performed whole-transcriptome sequencing of the longissimus dorsi muscle (IMF) from the high (5.1 ± 0.08) and low (2.9 ± 0.51) IMF groups (%) to elucidate potential mechanisms. In summary, 285 differentially expressed genes (DEGs), 14 differentially expressed miRNAs (DEMIs), 83 differentially expressed lncRNAs (DELs), and 79 differentially expressed circRNAs (DECs) were identified. DEGs were widely associated with IMF deposition and liposome differentiation. Furthermore, competing endogenous RNA (ceRNA) regulatory networks were constructed through co-differential expression analyses, which included circRNA-miRNA-mRNA (containing 6 DEMIs, 6 DEGs, 47 DECs) and lncRNA-miRNA-mRNA (containing 6 DEMIs, 6 DEGs, 36 DELs) regulatory networks. The circRNAs sus-TRPM7_0005, sus-MTUS1_0004, the lncRNAs SMSTRG.4269.1, and MSTRG.7983.2 regulate the expression of six lipid metabolism-related target genes, including PLCB1, BAD, and GADD45G, through the binding sites of 2-4068, miR-7134-3p, and miR-190a. For instance, MSTRG.4269.1 regulates its targets PLCB1 and BAD via miRNA 2_4068. Meanwhile, sus-TRPM7_0005 controls its target LRP5 through ssc-miR-7134-3P. These findings indicate molecular regulatory networks that could potentially be applied for the marker-assisted selection of IMF to enhance pork quality.

Identification of potential tissue-specific biomarkers involved in pig fat deposition through integrated bioinformatics analysis and machine learning

Backfat thickness (BT) and intramuscular fat (IMF) content are closely appertained to meat production and quality in pig production. Deposition in subcutaneous adipose (SA) and IMF concerns different genes and regulatory mechanisms. And larger studies with rigorous design should be carried to explore the molecular regulation of fat deposition in different tissues. The purpose of this study is to gain a better understanding of the molecular mechanisms underlying differences in fat deposition among different tissues and identify tissue-specific genes involved in regulating fat deposition. The SA-associated datasets (GSE122349 and GSE145956) and IMF-associated datasets (GSE165613 and GSE207279) were downloaded from the Gene Expression Omnibus (GEO) as the BT and IMF group, respectively. Subsequently, the Robust Rank Aggregation (RRA) algorithm identified 27 down- and 29 up-regulated differentially expressed genes (DEGs) in the BT group. Based on bioinformatics and three machine learning algorithms, four SA deposition-related potential biomarkers, namely ACLY, FASN, ME1, and ARVCF were selected. FASN was evaluated as the most valuable biomarker for the SA mechanism. The 18 down- and 34 up-regulated DEGs in the IMF group were identified, and ACTA2 and HMGCL were screened as the IMF deposition-related candidate core genes, especially the ACTA2 may play the critical role in IMF deposition regulation. Moreover, based on the constructed ceRNA network, we postulated that the role of predicted ceRNA interaction network of XIST, NEAT1/miR-15a-5p, miR-16-5p, miR-424-5p, miR-497-5p/FASN were vital in the SA metabolism, XIST, NEAT1/miR-27a/b-3p, 181a/c-5p/ACTA2 might contribute to the regulation to IMF metabolism, which all gave suggestions in molecular mechanism for regulation of fat deposition. These findings may facilitate advancements in porcine quality at the genetic and molecular levels and assist with human obesity-associated diseases.

Proteomic analysis of the liver regulating lipid metabolism in Chaohu ducks using two-dimensional electrophoresis.

In this study, we aimed to characterize the liver protein profile of Chaohu ducks using two-dimensional electrophoresis and proteomics. The livers were quickly collected from 120 healthy, 84-day-old Chaohu ducks. The intramuscular fat (IMF) content of the left pectoralis muscle was determined using the Soxhlet extraction method. The total protein of liver tissues from the high and low IMF groups was extracted for proteomics. Functional enrichment analysis of the differentially expressed proteins (DEPs) was conducted using gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG). In total, 43 DEPs were identified. Functional enrichment analysis indicated that these DEPs were significantly related to four lipid metabolic processes: carboxylic acid metabolic process, ATP metabolic process, oxoacid metabolic process, and organic acid metabolic process. Three pathways correlated with lipid metabolism were identified using KEGG analysis: glycolysis/gluconeogenesis, pentose phosphate pathway, fructose, and mannose metabolism. Eight key proteins associated with lipid metabolism were identified: ALDOB, GAPDH, ENO1, RGN, TPI1, HSPA9, PRDX1, and GPX1. Protein–protein interaction analysis revealed that the glycolysis/gluconeogenesis pathway mediated the interaction relationship. Key proteins and metabolic pathways were closely related to lipid metabolism and showed a strong interaction in Chaohu ducks.

Comparative analysis of differentially abundant proteins between high and low intramuscular fat content groups in donkeys.

Intramuscular fat (IMF) is an important regulator that determines meat quality, and its content is closely related to flavor, tenderness, and juiciness. Many studies have used quantitative proteomic analysis to identify proteins associated with meat quality traits in livestock, however, the potential candidate proteins that influence IMF in donkey muscle are not fully understood. In this study, we performed quantitative proteomic analysis, with tandem-mass-tagged (TMT) labeling, with samples from the longissimus dorsi (LD) muscle of the donkey. A total of 585,555 spectra were identified from the six muscle samples used in this study. In total, 20,583 peptides were detected, including 15,279 unique peptides, and 2,540 proteins were identified. We analyzed differentially abundant proteins (DAPs) between LD muscles of donkeys with high (H) and low (L) IMF content. We identified 30 DAPs between the H and L IMF content groups, of which 17 were upregulated and 13 downregulated in the H IMF group. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis of these DAPs revealed many GO terms (e.g., bone morphogenetic protein (BMP) receptor binding) and pathways (e.g., Wnt signaling pathway and Hippo signaling pathway) involved in lipid metabolism and adipogenesis. The construction of protein–protein interaction networks identified 16 DAPs involved in these networks. Our data provide a basis for future investigations into candidate proteins involved in IMF deposition and potential new approaches to improve meat quality in the donkey.

Comprehensive Analysis of Differentially Expressed mRNAs, lncRNAs and circRNAs Related to Intramuscular Fat Deposition in Laiwu Pigs.

Long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) are important classes of small noncoding RNAs that can regulate numerous biological processes. To understand the role of message RNA (mRNAs, lncRNAs and circRNAs) in the regulation of intramuscular fat (IMF) deposition, in this study the expression profiles of longissimus dorsi (LD) muscle from six Laiwu pigs (three with extremely high and three with extremely low IMF content) were sequenced based on rRNA-depleted library construction. In total, 323 differentially expressed protein-coding genes (DEGs), 180 lncRNAs (DELs) and 105 circRNAs (DECs) were detected between the high IMF and low IMF groups. Functional analysis indicated that most DEGs, and some target genes of DELs, were enriched into GO terms and pathways related to adipogenesis, suggesting their important roles in regulating IMF deposition. In addition, 12 DELs were observed to exhibit a positive relationship with stearoyl-CoA desaturase (SCD), phosphoenolpyruvate carboxykinase 1 (PCK1), and adiponectin (ADIPOQ), suggesting they are highly likely to be the target genes of DELs. Finally, we constructed a source gene-circRNA-miRNA connective network, and some of miRNA of the network have been reported to affect lipid metabolism or adipogenesis. Overall, this work provides a valuable resource for further research and helps to understand the potential functions of lncRNAs and circRNAs in IMF deposition.

Integrative Analysis of Nanopore and Illumina Sequencing Reveals Alternative Splicing Complexity in Pig Longissimus Dorsi Muscle.

Alternative splicing (AS) is a key step in the post-transcriptional regulation of gene expression that can affect intramuscular fat (IMF). In this study, longissimus dorsi muscles from 30 pigs in high- and low- IMF groups were used to perform Oxford Nanopore Technologies (ONT) full-length sequencing and Illumina strand-specific RNA-seq. A total of 43,688 full-length transcripts were identified, with 4,322 novel genes and 30,795 novel transcripts. Using AStalavista, a total of 14,728 AS events were detected in the longissimus dorsi muscle. About 17.79% of the genes produced splicing isoforms, in which exon skipping was the most frequent AS event. By analyzing the expression differences of mRNAs and splicing isoforms, we found that differentially expressed mRNAs with splicing isoforms could participate in skeletal muscle development and fatty acid metabolism, which might determine muscle-related traits. SERBP1, MYL1, TNNT3, and TNNT1 were identified with multiple splicing isoforms, with significant differences in expression. AS events occurring in IFI6 and GADD45G may cause significant differences in gene expression. Other AS events, such as ONT.15153.3, may regulate the function of ART1 by regulating the expression of different transcripts. Moreover, co-expression and protein-protein interaction (PPI) analysis indicated that several genes (MRPL27, AAR2, PYGM, PSMD4, SCNM1, and HNRNPDL) may be related to intramuscular fat. The splicing isoforms investigated in our research provide a reference for the study of alternative splicing regulation of intramuscular fat deposition.

Circular RNA Profiling Identifies Novel circPPARA that Promotes Intramuscular Fat Deposition in Pigs.

Intramuscular fat (IMF) content plays an important role in pork quality. Circular RNAs (circRNAs) implicate various biological processes; however, the regulatory mechanisms and functions of circRNAs in porcine IMF remains elusive. Hence, the study assessed the circRNA expression profiling in the longissimus dorsi muscle of pigs with high (H) and low (L) IMF content to unravel their regulatory functions in improving meat quality. The RNA sequencing analysis identified 29,732 circRNAs from six sampled pigs, most of which were exon-derived. In the muscle, 336 were differentially expressed (DE) between the H and L IMF groups; 196 circRNAs were upregulated, and 140 were downregulated. Subsequent qRT-PCR validation of 10 DE circRNAs revealed expression patterns consistent with the RNA-seq data. Gene ontology and KEGG enrichment analysis revealed that most significantly enriched DE circRNAs' host genes were linked to lipid metabolism and adipogenesis processes. The circRNA-miRNA regulatory network analysis found several circRNAs targeting miRNAs associated with adipogenesis. Finally, a novel circRNA, circPPARA, was identified with the expression positively correlated with the IMF content. Detailed analysis revealed that circPPARA was formed via head-to-tail splicing and was more stable than the linear PPARA, predominantly located in the cytoplasm. Functional studies using overexpression and siRNA constructs demonstrated that circPPARA promotes differentiation and hinders the proliferation of porcine intramuscular preadipocytes. Moreover, the dual-luciferase assay revealed that circPPARA adsorbed miR-429 and miR-200b, thereby promoting intramuscular adipogenesis in pigs. Our results identified a candidate circRNA, circPPARA, that affects porcine IMF content. The study provides knowledge of the regulatory functions of circRNAs in intramuscular adipogenesis and abundant resource for future research on circRNAs in pigs.

Identification of candidate genes that specifically regulate subcutaneous and intramuscular fat deposition using transcriptomic and proteomic profiles in Dingyuan pigs

Subcutaneous fat and intramuscular fat (IMF) deposition are closely related to meat production and pork quality. Dingyuan pig, as a native pig breed in China, low selection leads to obvious genetic and phenotypic differences in the population. Individuals with extreme fat content in the population are ideal models for studying the mechanism of fat deposition. In this study, we used RNA-Seq and tandem mass tags-based (TMT) proteomics to analyze the key pathways and genes that specifically regulate subcutaneous fat and IMF deposition in Dingyuan pigs. We identified 191 differentially expressed genes (DEGs) and 61 differentially abundant proteins (DAPs) in the high and low back fat thickness (HBF, LBF) groups, 85 DEGs and 12 DAPs were obtained in the high and low intramuscular fat (HIMF, LIMF) groups. The functional analysis showed that the DEGs and DAPs in the backfat groups were mainly involved in carbohydrates, amino acids, and fatty acids metabolism, whereas the IMF groups were involved in the insulin pathway, longevity, and some disease-related pathways. We found 40 candidate genes that might tissue-specifically lipids deposition for subcutaneous and intramuscular fat. Our research provides theoretical reference materials for the improvement of fat deposition traits of local pig breeds in my country.

Identification and functional prediction of long noncoding RNAs related to intramuscular fat content in Laiwu pigs.

ObjectiveIntramuscular fat (IMF) is a critical economic indicator of pork quality. Studies on IMF among different pig breeds have been performed via high-throughput sequencing, but comparisons within the same pig breed remain unreported.MethodsThis study was performed to explore the gene profile and identify candidate long noncoding RNA (lncRNAs) and mRNAs associated with IMF deposition among Laiwu pigs with different IMF contents. Based on the longissimus dorsi muscle IMF content, eight pigs from the same breed and management were selected and divided into two groups: a high IMF (>12%, H) and low IMF group (<5%, L). Whole-transcriptome sequencing was performed to explore the differentially expressed (DE) genes between these two groups.ResultsThe IMF content varied greatly among Laiwu pig individuals (2.17% to 13.93%). Seventeen DE lncRNAs (11 upregulated and 6 downregulated) and 180 mRNAs (112 upregulated and 68 downregulated) were found. Gene Ontology analysis indicated that the following biological processes played an important role in IMF deposition: fatty acid and lipid biosynthetic processes; the extracellular signal-regulated kinase cascade; and white fat cell differentiation. In addition, the peroxisome proliferator-activated receptor, phosphatidylinositol-3-kinase-protein kinase B, and mammalian target of rapamycin pathways were enriched in the pathway analysis. Intersection analysis of the target genes of DE lncRNAs and mRNAs revealed seven candidate genes associated with IMF accumulation. Five DE lncRNAs and 20 DE mRNAs based on the pig quantitative trait locus database were identified and shown to be related to fat deposition. The expression of five DE lncRNAs and mRNAs was verified by quantitative real time polymerase chain reaction (qRT-PCR). The results of qRT-PCR and RNA-sequencing were consistent.ConclusionThese results demonstrated that the different IMF contents among pig individuals may be due to the DE lncRNAs and mRNAs associated with lipid droplets and fat deposition.

Investigation of genetic markers for intramuscular fat in the hybrid Wagyu cattle with bulked segregant analysis

ulked Segregant Analysis (BSA) is a rapid strategy for identifying genetic markers in specific regions of the phenotypical population and it has been widely used for QTLs mapping in smaller mixed F2 and F3 populations. We applied a modified BSA method to assessed genome-wide homozygous and heterozygous linkage patterns in the Chinese Wagyu Beef Cattle F2/F3 mixed population. Two overlapped regions from F2 and F3 populations on autosomes were found with high-density heterozygote alleles between high and low intramuscular fat groups. Regions from 24.8 M ~ 29.6 M of chromosome 23 were identified as most significantly correlated to the intramuscular fat in our samples. We also identified other 4 potential loci on chromosomes 5, 9, 15, and 21 correlated with Intramuscular fat. This study provided a novel low-cost method for QTLs mapping and identify molecular markers of phenotypical changes in a small mixed population.

Thigh intramuscular fat predicts the prognosis in patients in non-ischemic cardiomyopathy with reduced ejection fraction

Abstract Background Skeletal muscle atrophy is an independent prognostic predictor for patients with chronic heart failure, and the concept of sarcopenia is drawing attention. Furthermore, the importance of not only muscle mass but also intramuscular fat (IMF) has been pointed out. However, there is a lack of consensus on the implications of ectopic fat for the prognosis in patients with non-ischemic cardiomyopathy. Purpose We investigated whether ectopic fat in the thigh affects the prognosis with non-ischemic cardiomyopathy. Methods We recruited 105 patients who were diagnosed with non-ischemic cardiomyopathy by cardiac catheterization and echocardiographic date between September 2017 and November 2019. Finally 73 patients with reduced EF (EF 40% or less) enrolled in this prospective study. Functional status was evaluated by using cardiopulmonary exercise test at baseline. All patients were measured quantity of epicardial fat and thigh IMF percentage (%IMF) using computed tomography scan. Demographic, laboratory and echocardiographic date were collected from the patients' medical records. Clinical endpoints were unexpected readmission. Results During the follow-up period 18 patients had adverse events. The %IMF was significantly higher in the group with adverse events than without (5.57±5.70 and 3.02±2.44%, respectively; p&amp;lt;0.01). Spearman correlation coefficient analysis showed a modest correlation between %IMF and lower limb extension strength (Spearman r=−0.280; p=0.0315), but there was no significant correlation between %IMF and exercise tolerance such as anaerobic threshold and peak oxygen uptake. Patients were divided into 2 groups according to the median values of %IMF. Kaplan-Meier analysis demonstrated that events were significantly higher in the high %IMF group (log-rank p=0.033). Multivariate Cox regression analysis adjusted for left ventricular end-diastolic diameter and peak ventricular oxygen consumption found %IMF as an independent factor of adverse events (hazard ratio 1.545; 95% confidential interval 1.151–2.087; p=0.004). Conclusions In non-ischemic cardiomyopathy patients with reduced EF, %IMF may have important adverse consequences such as increased cardiac-related events. Kaplan-Meier curves Funding Acknowledgement Type of funding source: None

Promoter CpG methylation status affects ADRP gene expression level and intramuscular fat content in pigs

Adipose differentiation-related protein (ADRP) is a lipid droplet-associated protein that is expressed early during adipose differentiation. However, the underlying mechanism is still unclear. In this study, the porcine ADRP (pADRP) gene regulatory mechanism and its relationship to intramuscular fat (IMF) content are analysed. We investigated the characteristics of the pADRP gene prompter as well as its transcription level, core promoter and epigenetic modification status using real-time PCR, Dual-luciferase reporter assays and bisulphite sequencing. The results showed that pADRP mRNA expression in Longissimus Dorsi (LD) muscle of the low IMF (LEAN) group was lower than that in the high IMF (FAT) group (p<.01). Maximum promoter activity was found in the −926 bp to −235 bp region. The methylation level of the pADRP of this region (mainly 7th, 10th, 12th CpG sites) in the low IMF group (86.67%) was significantly higher than that in the high IMF group (46.7%) (p<.01). Our result plays an important role in pADRP transcriptional regulation and provides a good prospect for the marbling traits improvement. Highlights pADRP expression differs in divergent IMF content pigs. Promoter region located −929 to −235 bp, and its methylation contributes to gene expression.

Evaluation of the Changes in Composition of Pork Chops During Cooking

ObjectivesThe objective was to determine the change in extractable lipid concentration during cooking of boneless pork chops to different endpoint temperatures. Intramuscular fat (IMF) concentration of pork chops changes during the cooking process when chops are cooked to 63°C, water is lost thereby concentrating extractable lipid. When chops are cooked to 71°C, water is lost, but it was hypothesized that lipid is lost as well. This would result in less variability in IMF of cooked chops compared with raw chops. This reduction in variability may explain the lack of sensory perception differences between chops with substantial marbling and chops with little marbling. This is important because consumers use marbling to make purchasing decisions. The hypothesis was that the range in IMF would be lessened after cooking due to moisture loss and potentially lipid loss at higher cooking temperatures. Ultimately, the variation in IMF in cooked pork chops would be less than that of fresh pork chops.Materials and MethodsPork loins (152 total) were used by cutting 3 consecutive chops from each loin. Chop 1 was evaluated raw (not cooked), chop 2 was cooked to 63°C, and chop 3 was cooked to 71°C before evaluation for IMF. These chops were divided into 3 separate bins based on raw IMF percentages. The low group consisted of chops with an IMF percentage equal to or less than 3%, the average group consisted of IMF percentages between 3 and 4% and the high IMF group consisted of chops with an IMF greater than 4%. Moisture and IMF were determined using duplicate 10-g samples from each chop. Samples were dried and IMF was determined with the chloroform-methanol solvent method. Cook loss was calculated by weighing chops before and after cooking. Warner-Bratzler Shear Force (WBSF) was determined by shearing 5 cores from each chop. Data were analyzed using a one-way ANOVA with the fixed effect of IMF level. Means were separated using a probability of difference statement and considered significantly different at P &lt; 0.05.ResultsRaw high IMF chops (4.94%) had greater (P &lt; 0.0001) IMF than average IMF chops (3.51%). Raw average IMF chops (3.51%) had greater (P &lt; 0.0001) IMF than low IMF chops (2.47%). High IMF chops cooked to 63°C (5.59%) had greater (P &lt; 0.0001) IMF than average IMF chops cooked to 63°C (4.17%). Average IMF chops cooked to 63°C (4.17%) had greater (P &lt; 0.0001) IMF than low IMF chops cooked to 63°C (3.39%). High IMF chops cooked to 71°C (6.12%) had greater (P &lt; 0.0001) IMF than average IMF chops cooked to 71°C (4.55%). Average IMF chops cooked to 71°C (4.55%) had greater (P &lt; 0.0001) IMF than low IMF chops cooked to 71°C (3.88%). Additionally, WBSF was not different (P ≥ 0.32) among high, average or low groups when cooked to 63°C or 71°C. Cook loss was not different (P ≥ 0.31) among high, average, or low groups when cooked to 63°C or 71°C. However, WBSF (2.77 kg) and cook loss (18.70%) was less in chops cooked to 63°C than when cooked to 71°C (3.10 kg, 23.37%).ConclusionThe hypothesis was that the range and variability in IMF would be lessened after cooking due to moisture loss and potentially lipid loss at higher cooking temperatures. This was not the case and the differences in IMF percentages persisted even after cooking. Furthermore, WBSF and cook loss did not differ among chops categorized as high, average, and low IMF categories. Ultimately, IMF percentage of raw or cooked chops did not affect tenderness.

Identification of differentially expressed genes and pathways between intramuscular and abdominal fat-derived preadipocyte differentiation of chickens in vitro

BackgroundThe distribution and deposition of fat tissue in different parts of the body are the key factors affecting the carcass quality and meat flavour of chickens. Intramuscular fat (IMF) content is an important factor associated with meat quality, while abdominal fat (AbF) is regarded as one of the main factors affecting poultry slaughter efficiency. To investigate the differentially expressed genes (DEGs) and molecular regulatory mechanisms related to adipogenic differentiation between IMF- and AbF-derived preadipocytes, we analysed the mRNA expression profiles in preadipocytes (0d, Pre-) and adipocytes (10d, Ad-) from IMF and AbF of Gushi chickens.ResultsAbF-derived preadipocytes exhibited a higher adipogenic differentiation ability (96.4% + 0.6) than IMF-derived preadipocytes (86.0% + 0.4) (p < 0.01). By Ribo-Zero RNA sequencing, we obtained 4403 (2055 upregulated and 2348 downregulated) and 4693 (2797 upregulated and 1896 downregulated) DEGs between preadipocytes and adipocytes in the IMF and Ad groups, respectively. For IMF-derived preadipocyte differentiation, pathways related to the PPAR signalling pathway, ECM-receptor interaction and focal adhesion pathway were significantly enriched. For AbF-derived preadipocyte differentiation, the steroid biosynthesis pathways, calcium signaling pathway and ECM-receptor interaction pathway were significantly enriched. A large number of DEGs related to lipid metabolism, fatty acid metabolism and preadipocyte differentiation, such as PPARG, ACSBG2, FABP4, FASN, APOA1 and INSIG1, were identified in our study.ConclusionThis study revealed large transcriptomic differences between IMF- and AbF-derived preadipocyte differentiation. A large number of DEGs and transcription factors that were closely related to fatty acid metabolism, lipid metabolism and preadipocyte differentiation were identified in the present study. Additionally, the microenvironment of IMF- and AbF-derived preadipocyte may play a significant role in adipogenic differentiation. This study provides valuable evidence to understand the molecular mechanisms underlying adipogenesis and fat deposition in chickens.

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.

Gene expression profile of Musculus longissimus dorsi in bulls of a Charolais × Holstein F 2 -cross with divergent intramuscular fat content

Transcriptomes of Musculus longissimus dorsi (MLD) were compared between bulls from a F2-cross derived from Charolais and Holstein Friesian. Two groups of 10 bulls were selected which differed significantly in intramuscular fat (IMF) deposition despite standardized husbandry and feeding conditions and identical sires in both groups. Consequently, genetic factors underlying the different capability of IMF deposition should be identified. A total of 32 differentially expressed genes (DEGs) were found of which 11 were up-regulated and 21 were down-regulated in the high IMF group. Ingenuity Pathway Analysis (IPA) identified a gene network comprising DEGs with functions in carbohydrate metabolism, lipid metabolism and molecular transport. The data from this study were deposited in NCBI's Gene Expression Omnibus and are accessible through GEO Series accession number GSE75347. We provide here a dataset which is of potential value to dissect molecular pathways influencing differences in IMF deposition in crossbred cattle with standardized genetic background.

Do all the consumers accept marbling in the same way? The relationship between eating and visual acceptability of pork with different intramuscular fat content

Several reports show that intramuscular fat (IMF) and/or marbling affect the sensory acceptability of meat. The aim of the present work was to (1) investigate using Spanish consumers the eating and visual acceptability of pork with different levels of IMF, (2) understand more about this acceptability by studying segments of consumers and (3) determine which fresh pork characteristics are important at the point of purchase. Loin section (n=40) were sorted into four IMF groups: 0.96±0.30% (G1), 2.11±0.07% (G2), 3.72±0.26% (G3), and 5.78±0.19% (G4). Consumers (n=200) evaluated the acceptability, tenderness and juiciness of cooked loin chops from each IMF group and then ranked raw chops according to visual preference. Two groups of consumers — ‘lean loin lovers’ (55.5%) and ‘marbled loin lovers’ (44.5%) — were identified based on their visual preferences; however, according to their eating acceptability scores, all the consumers preferred loins with higher IMF levels. Accordingly, the minimum IMF content recommended to ensure a good taste is between 2.2% and 3.4%.

Analysis of Relationships Between Fattening and Slaughter Performance of Pigs and the Level of Intramuscular Fat (IMF) in Longissimus Dorsi Muscle

Analysis of Relationships Between Fattening and Slaughter Performance of Pigs and the Level of Intramuscular Fat (IMF) in Longissimus Dorsi MuscleThe aim of the study was to determine the level of basic fattening and slaughter traits (growth rate, level of meatiness and fatness, age at slaughter) depending on different levels of intramuscular fat that determine different sensory perceptions of consumers. Subjects were 4430 gilts from pedigree farms, which were tested in performance stations. The breed composition of the animals was as follows (head): Polish Large White - 1240, Polish Landrace - 2083, Puławska - 104, Hampshire - 35, Duroc - 152, Pietrain - 208, line 990 - 608. Animals were kept in individual pens and fed standard diets. Intramuscular fat (IMF) content of the longissimus dorsi muscle was determined by Soxhlet using the SOXTHERM SOX 406 system (Gerhardt). The level of IMF served as a basis for dividing the test animals into three groups: below 2% (group I), between 2% and 3% (group II) and above 3% (group III). Animal breed had the highest and highly significant effect on the level of all traits analysed. As regards age at slaughter and carcass meat percentage, an interaction was found between animal breed and the group factor determined based on IMF level (P≤0.001). The factor expressed as IMF group had no effect on the level of analysed traits (P&gt;0.05). Therefore, the results of this analysis concerning the parameters obtained from live evaluation do not permit these data to be used in selection for improved IMF levels. The high rate of lean deposition in the modern breeds prevented genetic differences in the level of IMF to fully manifest themselves at a slaughter weight of about 100 kg. This unfavourable information leads one to look for other factors that determine variation of this trait.