Intramuscular Fat Content Research Articles

Evaluation of coffee husks in pellet bedding, performance characteristics, footpad dermatitis scoring, and meat quality of broiler ducks

The study aimed to analyze the chemical composition of pellet bedding made of straw or coffee husks (10, 25, 50%) and the performance characteristics of broiler ducks and footpad dermatitis. During rearing, the properties of the bedding and utility features of ducks were analyzed, and the frequency of footpad dermatitis (FPD) in ducks was verified. There was a decrease in dry matter from the 28th day of rearing. The crude fiber, NDF, ADF, and nitrogen content decreased compared to fresh bedding, while phosphorus and potassium increased. The highest pH was found in the CH25 and CH50 groups in fresh bedding on day 42 and in CH50 on day 14. High adj. R2 was found due to rearing time and bedding material (0.817–0.985). The ducks’ growth rate in the CH25 group was higher at week 6 than in the other groups. In CH10 and CH25 groups, higher carcass weight was found than in group C. In group CH10, a higher weight of pectoral muscles and lower wing proportion was found than in C. In CH25, a higher remains weight was shown than in C and CH50. In CH50, lower water-holding capacity in the pectoral muscles was found than in the other groups. Considering the bedding (the content of nitrogen, phosphorus, and potassium), carcass features, and meat quality (water-holding capacity, intramuscular fat, and water content), it is possible to use 10, 25 or 50% of coffee husks in straw pellets in the rearing of broiler ducks. Due to the FPD, the moisture should be lowered.

Identification of key genes related to intramuscular fat deposition in Beijing-You chicken by mRNA and miRNA transcriptome analysis

Intramuscular fat (IMF) is an important factor affecting chicken quality. However, the age-related mechanism of IMF deposition has not yet been elucidated. In this study, the IMF, phospholipids (PL), triglycerides (TG), and fatty acid (FA) content in the breast muscle of Beijing-You chicken (BJY) at 1, 56, 98, and 120 d of age was measured, and mRNA and miRNA sequencing was integrated to explore the regulatory genes of IMF deposition. The results showed that the IMF content of BJY at 1 d of age was significantly higher than that at later stage of birth (P < 0.05). The transcriptome sequencing results showed that 7, 225 differentially expressed genes (DEGs) and 243 differentially expressed miRNAs (DE-miRNAs) were identified. The cluster analysis showed that the expression of DEGs and DE-miRNAs at 1 d of age was significantly different from that at later stages of birth. Furthermore, a potential mRNA-miRNA regulatory network related to IMF deposition was established by weighted gene co-expression network analysis (WGCNA); gga-miR-29c-3p-PIK3R1, gga-miR-6701-3p-PTEN, gga-miR-363-3p-PTEN, gga-miR-1563-WWP1, gga-miR-449c/d-5p-TRAF6, and gga-miR-6701-3p-BMPR1B were identified as key mRNA-miRNA pairs for the regulation of IMF deposition. These results will help elucidate the mechanism of IMF formation mediated by miRNAs in chickens, and provide a theoretical foundation for the genetic improvement of broiler meat quality.

Integrated Comparative Transcriptome and circRNA-lncRNA-miRNA-mRNA ceRNA Regulatory Network Analyses Identify Molecular Mechanisms Associated with Intramuscular Fat Content in Beef Cattle.

Intramuscular fat content (IMF), one of the most important carcass traits in beef cattle, is controlled by complex regulatory factors. At present, molecular mechanisms involved in regulating IMF and fat metabolism in beef cattle are not well understood. Our objective was to integrate comparative transcriptomic and competing endogenous RNA (ceRNA) network analyses to identify candidate messenger RNAs (mRNAs) and regulatory RNAs involved in molecular regulation of longissimus dorsi muscle (LDM) tissue for IMF and fat metabolism of 5 beef cattle breeds (Angus, Chinese Simmental, Luxi, Nanyang, and Shandong Black). In total, 34 circRNAs, 57 lncRNAs, 15 miRNAs, and 374 mRNAs were identified by integrating gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Furthermore, 7 key subnets with 16 circRNAs, 43 lncRNAs, 7 miRNAs, and 237 mRNAs were detected through clustering analyses, whereas GO enrichment analysis of identified RNAs revealed 48, 13, and 28 significantly enriched GO terms related to IMF in biological process, molecular function, and cellular component categories, respectively. The main metabolic-signaling pathways associated with IMF and fat metabolism that were enriched included metabolic, calcium, cGMP-PKG, thyroid hormone, and oxytocin signaling pathways. Moreover, MCU, CYB5R1, and BAG3 genes were common among the 10 comparative groups defined as important candidate marker genes for fat metabolism in beef cattle. Contributions of transcriptome profiles from various beef breeds and a competing endogenous RNA (ceRNA) regulatory network underlying phenotypic differences in IMF provided novel insights into molecular mechanisms associated with meat quality.

Muscle proteome of crossbred cattle that received vitamin A at birth: impacts on meat quality traits

This study aimed to evaluate the skeletal muscle proteome of calves that received an intramuscular application of vitamin A at birth and its impacts on meat quality. Forty male crossbred calves were used from birth to feedlot finishing. On the day of birth, 20 calves were injected intramuscularly with a single dose of 300,000 IU of vitamin A and the other 20 animals received placebo (control). After weaning at 210 days, the animals of the two treatments were feedlot finished for 180 days. Longissimus muscle samples were collected for proteome analysis and meat quality assessment. There was a trend (P = 0.07) towards more tender meat in animals that received vitamin A compared to control (WBSF = 3.92 ± 0.16 kg vs. 4.23 ± 0.15). Meat color, pH and cooking loss were not affected (P > 0.05). Vitamin A treatment resulted in a more than 50% increase in intramuscular fat (IMF) content (P < 0.05) compared to control (4.10 ± 0.35% vs. 2.57 ± 0.27%). The intramuscular injection of vitamin A affected the post-mortem muscle proteome and the protein-protein interactions. A greater abundance of proteins involved in three main pathways were observed these being energy metabolism (GAPDH, ENO3, TPI1, CKM, and COX5A), muscle contraction (ACTB, ACTC1, ACTG1, ACTG2, ACTA1, ACTA2, ACTN1, ACTN2, ACTN3, TPM1, TPM2, TPM3, MYH1, PDLIM3, and TNNT3), protein binding, transport, and signaling (TUBA4A, VIM, TBA1B, and EEF1A2). A greater abundance of oxidative stress and cellular defense proteins (HSPA8 and DNAJC18) was specifically observed in the control treatment. Vitamin A upregulated key biological processes related to energy metabolism, which favored IMF accumulation during the finishing phase.

Fatty Acid Synthase Polymorphism of Awassi Sheep and its Impact on Fatty Acid Composition

Livestock intramuscular fat content is determined by fatty acid synthase (FASN). The fatty acid profile of the fat is of relevance to human health.  Thus, this study explores the relationship between the polymorphism of the FASN gene in Awassi sheep and its impact on fatty acid composition. The study used 100 Awassi rams, ranging in age from 1 to 2.5 years. Molecular DNA was isolated from each blood sample; genotyping, sequencing reactions, and in silico tools were subsequently used to confirm the variants in amplified fragments.  The results revealed two genotypes (GG and GA) of the ovine FASN gene (exon 2). The novel missense c.186 GA was identified in the genotype GA.  The GA genotype had significantly (P0.05) increased intramuscular fat, higher unsaturated fatty acid content, and lower saturated fatty acid content than the GG genotype. Cumulative in silico analysis indicated a detrimental effect of the SNP c.186 GA on FASN activity. The intramuscular GA genotype of Awassi sheep had a low saturated content relative to unsaturated fats. The result confirmed that the c.186 GA SNP in ovine FASN gene variation is potentially helpful in assessing carcass traits, and this might lead to a more efficient selection of animals with healthier fatty acid profiles, resulting in higher-quality meat.

Similarities and differences in skeletal muscle and body composition between sexes: an MRI study of recreational cyclists

ObjectivesThis study aims to quantitatively evaluate whether there are muscle mass differences between male and female recreational cyclists and compare muscle quality and body composition in the pelvis region between...

Transcriptomic Profiling of Meat Quality Traits of Skeletal Muscles of the Chinese Indigenous Huai Pig and Duroc Pig.

The Huai pig is a well-known indigenous pig breed in China. The main advantages of Huai pigs over Western commercial pig breeds include a high intramuscular fat (IMF) content and good meat quality. There are significant differences in the meat quality traits of the same muscle part or different muscle parts of the same variety. To investigate the potential genetic mechanism underlying the meat quality differences in different pig breeds or muscle groups, longissimus dorsi (LD), psoas major (PM), and biceps femoris (BF) muscle tissues were collected from two pig breeds (Huai and Duroc). There were significant differences in meat quality traits and amino acid content. We assessed the muscle transcriptomic profiles using high-throughput RNA sequencing. The IMF content in the LD, PM, and BF muscles of Huai pigs was significantly higher than that in Duroc pigs (p < 0.05). Similarly, the content of flavor amino acids in the three muscle groups was significantly higher in Huai pigs than that in Duroc pigs (p < 0.05). We identified 175, 110, and 86 differentially expressed genes (DEGs) between the LD, PM, and BF muscles of the Huai and Duroc pigs, respectively. The DEGs of the different pig breeds and muscle regions were significantly enriched in the biological processes and signaling pathways related to muscle fiber type, IMF deposition, lipid metabolism, PPAR signaling, cAMP signaling, amino acid metabolism, and ECM-receptor interaction. Our findings might help improve pork yield by using the obtained DEGs for marker-assisted selection and providing a theoretical reference for evaluating and improving pork quality.

FOXO1 regulates the formation of bovine fat by targeting CD36 and STEAP4

Intramuscular fat content is closely related to the quality of beef, where the forkhead box protein O1 (FOXO1) is involved in adipocyte differentiation and lipid metabolism, but the specific mechanism of its involvement is still unclear. In this study, interfering with FOXO1 promoted the G1/S transformation of bovine adipocytes by enhancing the expression of proliferation marker genes PCNA, CDK1, CDK2, CCNA2, CCNB1, and CCNE2, thereby positively regulating the proliferation of bovine adipocytes. Additionally, interfering with FOXO1 negatively regulated the expression of adipogenic differentiation marker genes PPARG and CEBPA, as well as lipid anabolism marker genes ACC, FASN, SCD1, SREBP1, FABP4, ACSL1, LPL, and DGAT1, thus reducing triglyceride (TG) content and inhibiting the generation of lipid droplets in bovine adipocytes. A combination of transcriptomic and metabolomics analyses revealed that FOXO1 could regulate the lipogenesis of cattle by influencing the AMPK and PI3K/AKT pathways. Importantly, chromatin immunoprecipitation (ChIP) and site-directed mutagenesis revealed that FOXO1 could regulate bovine lipogenesis by binding to the promoter regions of the CD36 and STEAP4 genes and affecting their transcriptional activities. These results provide a foundation for studying the role and molecular mechanism of FOXO1 in the bovine adipogenesis.

Effect of the combined use of monensin with virginiamycin or bacitracin on beef cattle performance, liver gluconeogenesis, lipid metabolism and intramuscular fat content

The objective was to evaluate the combined use of monensin with virginiamycin or zinc bacitracin on performance, serum D-lactate, feeding behavior, carcass traits, and the expression of gluconeogenic and lipogenic genes over time in feedlot young bulls. Nellore × Angus (F1) young bulls (n = 72; BW 368 ± 16.3 kg) were used in a completely randomized design. Animals were stratified by BW and allotted into 18 pens with 4 animals each. Pens (6 pens per treatment) were randomly assigned to the following treatments: monensin (MON), monensin + zinc bacitracin (MONZB) and monensin + virginiamycin (MONVM). The doses of monensin, zinc bacitracin and virginiamycin were 18.9, 6.62 and 18.9 mg/kg DM of the diet, respectively. The diet consisted of 85% corn-based concentrate and 15% corn silage. The finishing phase was 109 days with the first 27 days for diet adaptation and the remaining 82 days for the finishing diet. Treatment additives did not affect body weight (BW), overall average daily gain (ADG), dry matter intake (DMI) or gain:feed (P ≥ 0.13). Animals fed MONVM had lesser (P = 0.03) intramuscular fat than those fed MON and MONZB. Serum D-lactate concentration was greater (P = 0.05) in MONVM animals than in MON and MONZB animals. In the liver, MONVM animals upregulated (P < 0.03) Pyruvate carboxylase (PC) and Lactate dehydrogenase A (LDHA) expression compared with MON and MONZB. The expression of Peroxisome proliferator-activated receptor gamma (PPARG) in LT tended to be decreased (P = 0.07) in MONVM animals than in MONZB. Animals fed MONVM downregulated (P = 0.03) Acetyl-CoA carboxylase alpha (ACACA) expression compared with those fed MON. In conclusion, these additives affect growth performance in different times during feedlot phase. The combined use of monensin and virginiamycin reduce lipogenesis and increase lipid oxidation, triggering lesser IMF deposition compared to monensin alone or combined with bacitracin.

Regulatory role of N6-methyladenosine in intramuscular fat deposition in chicken

Intramuscular fat (IMF) has a pivotal influence on meat quality, with its deposition being a multifaceted physiological interaction of several regulatory factors. N6-methyladenosine (m6A), the preeminent epigenetic alteration among eukaryotic RNA modifications, holds a crucial role in moderating post-transcriptional gene expression. However, there is a dearth of comprehensive understanding regarding the functional machinery of m6A modification in the context of IMF deposition in poultry. Our current study entails an analysis of the disparities in IMF within the breast and leg of 180-day-old Jingyuan chickens. We implemented methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) to delve into the distribution of m6A and its putative regulatory frameworks on IMF deposition in chickens. The findings demonstrated a markedly higher IMF content in leg relative to breast (P < 0.01). Furthermore, the expression of METTL14, WTAP, FTO, and ALKBH5 was significantly diminished in comparison to that of breast (P < 0.01). The m6A peaks in the breast and leg primarily populated 3'untranslated regions (3'UTR) and coding sequence (CDS) regions. The leg, when juxtaposed with the breast, manifested 176 differentially methylated genes (DMGs), including 151 hyper-methylated DMGs and 25 hypo-methylated DMGs. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed a pronounced enrichment of DMGs in the biosynthesis of amino acids, peroxisome, Fatty acid biosynthesis, fatty acid elongation, and cell adhesion molecules (CAMs) pathways. Key DMGs, namely ECH1, BCAT1, and CYP1B1 were implicated in the regulation of muscle lipid anabolism. Our study offers substantial insight and forms a robust foundation for further exploration of the functional mechanisms of m6A modification in modulating IMF deposition. This holds profound theoretical importance for improving and leveraging meat quality in indigenous chicken breeds.

A single-cell atlas of bovine skeletal muscle reveals mechanisms regulating intramuscular adipogenesis and fibrogenesis.

Intramuscular fat (IMF) and intramuscular connective tissue (IMC) are often seen in human myopathies and are central to beef quality. The mechanisms regulating their accumulation remain poorly understood. Here, we explored the possibility of using beef cattle as a novel model for mechanistic studies of intramuscular adipogenesis and fibrogenesis. Skeletal muscle single-cell RNAseq was performed on three cattle breeds, including Wagyu (high IMF), Brahman (abundant IMC but scarce IMF), and Wagyu/Brahman cross. Sophisticated bioinformatics analyses, including clustering analysis, gene set enrichment analyses, gene regulatory network construction, RNA velocity, pseudotime analysis, and cell-cell communication analysis, were performed to elucidate heterogeneities and differentiation processes of individual cell types and differences between cattle breeds. Experiments were conducted to validate the function and specificity of identified key regulatory and marker genes. Integrated analysis with multiple published human and non-human primate datasets was performed to identify common mechanisms. A total of 32708 cells and 21 clusters were identified, including fibro/adipogenic progenitor (FAP) and other resident and infiltrating cell types. We identified an endomysial adipogenic FAP subpopulation enriched for COL4A1 and CFD (log2FC=3.19 and 1.92, respectively; P<0.0001) and a perimysial fibrogenic FAP subpopulation enriched for COL1A1 and POSTN (log2FC=1.83 and 0.87, respectively; P<0.0001), both of which were likely derived from an unspecified subpopulation. Further analysis revealed more progressed adipogenic programming of Wagyu FAPs and more advanced fibrogenic programming of Brahman FAPs. Mechanistically, NAB2 drives CFD expression, which in turn promotes adipogenesis. CFD expression in FAPs of young cattle before the onset of intramuscular adipogenesis was predictive of IMF contents in adulthood (R2 =0.885, P<0.01). Similar adipogenic and fibrogenic FAPs were identified in humans and monkeys. In aged humans with metabolic syndrome and progressed Duchenne muscular dystrophy (DMD) patients, increased CFD expression was observed (P<0.05 and P<0.0001, respectively), which was positively correlated with adipogenic marker expression, including ADIPOQ (R2 =0.303, P<0.01; and R2 =0.348, P<0.01, respectively). The specificity of Postn/POSTN as a fibrogenic FAP marker was validated using a lineage-tracing mouse line. POSTN expression was elevated in Brahman FAPs (P<0.0001) and DMD patients (P<0.01) but not in aged humans. Strong interactions between vascular cells and FAPs were also identified. Our study demonstrates the feasibility of beef cattle as a model for studying IMF and IMC. We illustrate the FAP programming during intramuscular adipogenesis and fibrogenesis and reveal the reliability of CFD as a predictor and biomarker of IMF accumulation in cattle and humans.

Epigenomics Analysis of the Suppression Role of SIRT1 via H3K9 Deacetylation in Preadipocyte Differentiation.

Sirtuin 1 (SIRT1) overexpression significantly inhibits lipid deposition during yak intramuscular preadipocyte (YIMA) differentiation; however, the regulatory mechanism remains unknown. We elucidated the role of SIRT1 in YIMA differentiation using lentivirus-mediated downregulation technology and conducted mRNA-seq and ChIP-seq assays using H3K9ac antibodies after SIRT1 overexpression in order to reveal SIRT1 targets during YIMA adipogenesis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed in order to identify the functional annotation of common genes. In addition, a potential target of SIRT1 was selected to verify its effects on the differentiation and proliferation of YIMAs. SIRT1 interfered with lipid deposition and promoted YIMA differentiation. In total, 143,518 specific peaks were identified after SIRT1 overexpression, where genes associated with downregulation peaks were enriched in transcription, gene expression, lipid-related processes, and classical lipid-related pathways. The H3K9ac signal in the whole genome promoter region (2 kb upstream and downstream of the transcription start site (TSS)) was weakened, and the peaks were distributed across all gene functional regions. Genes that lost signals in their TSS region or gene body region were enriched in both biological processes and pathways associated with lipogenesis. The ChIP-seq results revealed 714 common differential genes in mRNA-seq, which were enriched in "MAPK signaling", "lipid and atherosclerosis", "mTOR signaling", and "FoxO signaling" pathways. A total of 445 genes were downregulated in both their H3K9ac signals and mRNA expression, and one of their most significantly enriched pathways was FoxO signaling. Nine genes (FBP2, FPGT, HSD17B11, KCNJ15, MAP3K20, SLC5A3, TRIM23, ZCCHC10, and ZMYM1) lost the H3K9ac signal in their TSS regions and had low mRNA expression, and three genes (KCNJ15, TGM3, and TRIM54) had low expression but lost their H3K9ac signal in the gene body region. The interference of TRIM23 significantly inhibited fat deposition during preadipocyte differentiation and promoted cell proliferation by increasing S-phase cell numbers. The present study provides new insights into the molecular mechanism of intramuscular fat content deposition and the epigenetic role of SIRT1 in adipocyte differentiation.

Effects of the Breeding Strategy Beef-on-Dairy at Animal, Farm and Sector Levels.

The decline in farm revenue due to volatile milk prices has led to an increase in the use of beef semen in dairy herds. While this strategy ("Beef-on-dairy" (BoD)) can have economic benefits, it can also lead to unintended consequences affecting animal welfare. Semen sale trends from breeding organizations depict increasing sales of beef semen across the globe. Calves born from such breeding strategies can perform better when compared to purebred dairy calves, especially in terms of meat quality and growth traits. The Beef-on-dairy strategy can lead to unintentional negative impacts including an increase in gestation length, and increased dystocia and stillbirth rates. Studies in this regard have found the highest gestation length for Limousin crossbred calves followed by calves from the Angus breed. This increase in gestation length can lead to economic losses ranging from 3 to 5 US$ per animal for each additional day. In terms of the growth performance of crossbred animals, literature studies are inconclusive due to the vast differences in farming structure across the regions. But almost all the studies agree regarding improvement in the meat quality in terms of color, fiber type, and intra-muscular fat content for crossbred animals. Utilization of genomic selection, and development of specialized Beef-on-dairy indexes for the sires, can be a viable strategy to make selection easier for the farmers.

A Comparative Study on the Adipogenic and Myogenic Capacity of Muscle Satellite Cells, and Meat Quality Characteristics between Hanwoo and Vietnamese Yellow Steers.

Myogenesis and adipogenesis are the important processes determining the muscle growth and fat accumulation livestock, which ultimately affecting their meat quality. Hanwoo is a popular breed and its meat has been exported to other countries. The objective of this study was to compare the myogenesis and adipogenesis properties in satellite cells, and meat quality between Hanwoo and Vietnamese yellow cattle (VYC). Same 28-months old Hanwoo (body weight: 728±45 kg) and VYC (body weight: 285±36 kg) steers (n=10 per breed) were used. Immediately after slaughter, tissue samples were collected from longissimus lumborum (LL) muscles for satellite cells isolation and assays. After 24 h post-mortem, LL muscles from left carcass sides were collected for meat quality analysis. Under the same in vitro culture condition, the proliferation rate was higher in Hanwoo compared to VYC (p<0.05). Fusion index was almost 3 times greater in Hanwoo (42.17%), compared with VYC (14.93%; p<0.05). The expressions of myogenesis (myogenic factor 5, myogenic differentiation 1, myogenin, and myogenic factor 6)- and adipogenesis (peroxisome proliferator-activated receptor gamma)-regulating genes, and triglyceride content were higher in Hanwoo, compared with VYC (p<0.05). Hanwoo beef had a higher intramuscular fat and total monounsaturated fatty acids contents than VYC beef (p<0.05). Whilst, VYC meat had a higher CIE a* and total polyunsaturated fatty acids content (p<0.05). Overall, there was a significant difference in the in vitro culture characteristics and genes expression of satellite cells, and meat quality between the Hanwoo and VYC.

Effects of dietary niacinamide and CP concentrations on the nitrogen excretion, growth performance, and meat quality of pigs.

Reducing the dietary CP concentration in the formulation of low-protein diets without adverse effects on animal growth performance and meat quality remains challenging. In this study, we investigated the effects of nicotinamide (NAM) on the nitrogen excretion, growth performance, and meat quality of growing-finishing pigs fed low-protein diets. To measure the nitrogen balance, we conducted two trials: in nitrogen balance trial 1, four crossbred (Duroc×Landrace×Large White) barrows (40±0.5kg BW) were used in a 4×4 Latin square design with four diets and periods. The diets consisted of a basal diet+30mg/kg NAM (a control dose), basal diet+90mg/kg NAM, basal diet+210mg/kg NAM, and basal diet+360mg/kg NAM. In nitrogen balance trial 2, another four barrows (40±0.5kg BW) were used in a 4×4 Latin square design. The diets consisted of a basal diet+including 30mg/kg NAM (control), basal diet+360mg/kg NAM, low-protein diet+30mg/kg NAM, and low-protein diet+360mg/kg NAM. To measure growth performance, two trials were conducted. In growth performance trial 1, 40 barrows (37.0±1.0kg) were randomly allocated to one of four dietary treatments (n=10 per group), whereas in growth performance trial 2, 300 barrows (41.4±2.0kg) were randomly allocated to one of four dietary treatments, with each dietary treatment conducted in five repetitions with 15 pigs each. The four diets in the two growth performance trials were similar to those in nitrogen balance trial 2. Supplementing the diet with 210 or 360mg/kg NAM reduced urinary nitrogen excretion and total nitrogen excretion and increased nitrogen retention comparted with the control diet (P<0.05). Compared with the control diet, the low-protein diet with 360mg/kg NAM reduced faecal, urinary, and total nitrogen excretion (P<0.05) without affecting nitrogen retention and average daily gain (P>0.05). Pigs fed the low-protein diet with 360mg/kg NAM showed a decreased intramuscular fat content in the longissimus thoracis muscle when compared with pigs fed the control diet (P>0.05). Our results suggest NAM as a suitable dietary additive to reduce dietary CP concentration, maximise nitrogen retention and growth performance, and decrease fat deposition in pigs.

Genetic dissection of 26 meat cut, meat quality and carcass traits in four pig populations

BackgroundCurrently, meat cut traits are integrated in pig breeding objectives to gain extra profit. However, little is known about the heritability of meat cut proportions (MCP) and their correlations with other traits. The aims of this study were to assess the heritability and genetic correlation of MCP with carcass and meat quality traits using single nucleotide polymorphism chips and conduct a genome-wide association study (GWAS) to identify candidate genes for MCP.ResultsSeventeen MCP, 12 carcass, and seven meat quality traits were measured in 2012 pigs from four populations (Landrace; Yorkshire; Landrace and Yorkshire hybrid pigs; Duroc, and Landrace and Yorkshire hybrid pigs). Estimates of the heritability for MCP ranged from 0.10 to 0.55, with most estimates being moderate to high and highly consistent across populations. In the combined population, the heritability estimates for the proportions of scapula bone, loin, back fat, leg bones, and boneless picnic shoulder were 0.44 ± 0.04, 0.36 ± 0.04, 0.44 ± 0.04, 0.38 ± 0.04, and 0.39 ± 0.04, respectively. Proportion of middle cuts was genetically significantly positively correlated with intramuscular fat content and backfat depth. Proportion of ribs was genetically positively correlated with carcass oblique length and straight length (0.35 ± 0.08 to 0.45 ± 0.07) and negatively correlated with backfat depth (− 0.26 ± 0.10 to − 0.45 ± 0.10). However, weak or nonsignificant genetic correlations were observed between most MCP, indicating their independence. Twenty-eight quantitative trait loci (QTL) for MCP were detected by GWAS, and 24 new candidate genes related to MCP were identified, which are involved with growth, height, and skeletal development. Most importantly, we found that the development of the bones in different parts of the body may be regulated by different genes, among which HMGA1 may be the strongest candidate gene affecting forelimb bone development. Moreover, as previously shown, VRTN is a causal gene affecting vertebra number, and BMP2 may be the strongest candidate gene affecting hindlimb bone development.ConclusionsOur results indicate that breeding programs for MCP have the potential to enhance carcass composition by increasing the proportion of expensive cuts and decreasing the proportion of inexpensive cuts. Since MCP are post-slaughter traits, the QTL and candidate genes related to these traits can be used for marker-assisted and genomic selection.

Feeding regimens affecting carcass and quality attributes of sheep and goat meat - A comprehensive review.

Sheep and goats can efficiently convert low quality forage into high-quality meat which contains specific nutrients and quality traits. Carcass traits and quality attributes of sheep and goat meat depend upon several factors and one of most effective strategies amongst these is feeding regimens. In this review, the major aspects of feeding regimens affecting growth rate, carcass traits and quality attributes of sheep and goat meat are thoroughly discussed, with a particular focus on physical-chemical composition, flavor profile, and fatty acid (FA) profile. Grazing lambs and kids receiving concentrate or under stall-feeding systems had greater average daily gain and carcass yield compared with animals reared on pasture only. However, growth rate was higher in lambs/kids grazing on pastures of improved quality. Moreover, the meat of grazing lambs receiving concentrate had more intense flavor, intramuscular fat (IMF) content, and unhealthy FA composition, but comparable color, tenderness, juiciness, and protein content compared to that of lambs grazed on grass only. In contrast, meat of concentrate-fed lambs had more intense color, greater tenderness and juiciness, IMF and protein contents, and lower flavor linked to meat. Additionally, the meat of kids grazed on concentrate supplementation had higher color coordinates, tenderness, IMF content and unhealthy FA composition, whereas juiciness and flavor protein content were similar. In contrast, kids with concentrate supplementation had superior color coordinates, juiciness, IMF content and unhealthy FA composition, but lower tenderness and flavor intensity compared to pasture-grazed kids. Thus, indoor-finished or supplemented grazing sheep/goats had higher growth rate and carcass quality, higher IMF content and unhealthy FA composition compared to animals grazed on grass only. Finally, supplementation with concentrate increased flavor intensity in lamb meat, and improved color and tenderness in kid meat, whereas indoor-fed sheep/goats had improved color and juiciness as well as reduced flavor compared to pasture-grazed animals.

Dietary Supplementation with Rutin Alters Meat Quality, Fatty Acid Profile, Antioxidant Capacity, and Expression Levels of Genes Associated with Lipid Metabolism in Breast Muscle of Qingyuan Partridge Chickens.

Consumer demand for tasty and quality meat has been quickly increasing. This study investigated how dietary supplemented rutin affects meat quality, muscle fatty acid profile, and antioxidant capacity in the Chinese indigenous Qingyuan partridge chicken. A cohort of 180 healthy 119-day-old chickens was subjected to a randomized assignment into three groups, identified as the control, R200, and R400 groups, with respective supplementation of 0, 200, and 400 mg/kg of rutin. The results revealed insignificance in growth performance, namely, average daily gain, average daily feed intake, and feed-to-gain ratio, across the various treatment groups (p > 0.05). Nevertheless, dietary rutin supplementation increased (p < 0.05) breast muscle yield and intramuscular fat content in breast muscle and decreased (p < 0.05) drip loss in breast muscle. Rutin supplementation increased (p < 0.05) the content of high-density lipoprotein but decreased (p < 0.05) the contents of glucose, triglyceride, and total cholesterol in serum. Rutin supplementation increased (p < 0.05) the levels of DHA (C22:6n-3), total polyunsaturated fatty acids (PUFAs), n-3 PUFAs, decanoic acid (C10:0), the activity of Δ5 + Δ6 (22:6 (n - 3)/18:3 (n - 3)), and the ratio of PUFA/SFA in breast muscle but decreased (p < 0.05) the level of palmitoleic acid (C16:1n-7), the ratio of n-6/n-3 PUFAs, and the activity of Δ9 (16:1 (n - 7)/16:0). Rutin treatment also reduced (p < 0.05) the contents of malondialdehyde in serum and breast muscle, and increased (p < 0.05) the catalase activity and total antioxidant capacity in serum and breast muscle and the activity of total superoxide dismutase in serum. Additionally, rutin supplementation downregulated the expression of AMPKα and upregulated the expression of PPARG, FADS1, FAS, ELOVL7, NRF2, and CAT in breast muscle (p < 0.05). Convincingly, the results revealed that rutin supplementation improved meat quality, fatty acid profiles, especially n-3 PUFAs, and the antioxidant capacity of Qingyuan partridge chickens.

Integrated LC/MS-based lipidomics and transcriptomics analyses revealed lipid composition heterogeneity between pectoralis intramuscular fat and abdominal fat and its regulatory mechanism in chicken

Intramuscular fat (IMF) content is conducive to multiple meat quality properties, while abdominal fat (AF) is treated as waste product in chicken industry. However, the heterogeneity and distinct regulatory mechanisms of lipid composition between the IMF and AF are still unclear. In this study, we carried out non-targeted lipidomics analyses of pectoralis IMF and AF, and detected a total of 423 differential lipid molecules (DLMs) between chicken IMF and AF, including 307 up-regulated and 116 down-regulated DLMs in pectoral IMF. These DLMs exhibited the definite alteration of lipid composition. The up-reglated DLMs in IMF were mainly glycerophospholipids (GPs), including the bulk of phosphatidylcholines (PC, PC (P) and PC (O)), phosphatidylethanolamines (PE, PE (P) and PE (O)), phosphatidylglycerols (PG) and phosphatidylinositol (PI), while the up-reglated DLMs in AF were mainly glycerolipids (GLs), including most of triacylglycerols (TG) and diacylglycerols (DG). We further identified 28 main DLMs contributing to the heterogeneous deposition of IMF and AF, including 11 TGs common to IMF and AF, 12 PCs/PC (P)s specific to IMF and 5 DGs specific to AF. Further integration of transcriptome with the main DLMs by weighted gene co-expression network analysis (WGCNA), we found five key gene sets that included 386 unique genes promoting IMF deposition in pectoralis, 213 unique genes promoting AF deposition, 6 unique genes detrimental to AF deposition, 7 common genes that promote IMF deposition in pectoralis while adversely affect AF deposition, and 28 genes that only promoted IMF deposition in pectoralis but had no effect on AF deposition. In addition, we also observed the expression characteristics of key genes in vivo and in vitro, and found that transmembrane protein family gene TMEM164 might be mainly involved in the positive regulation of intramuscular fat deposition in pectoralis and zinc finger protein family gene ZNF488 had a potential unique positive regulatory function on abdominal fat deposition. These findings provide new perspectives for understanding IMF and AF heterodeposition and will serve as a valuable information resource for improving meat quality via breeding selection in chicken.

Single-nucleus and bulk RNA sequencing reveal cellular and transcriptional mechanisms underlying lipid dynamics in high marbled pork

Pork is the most consumed meat in the world, and its quality is associated with human health. Intramuscular fat (IMF) deposition (also called marbling) is a key factor positively correlated with various quality traits and lipo-nutritional values of meat. However, the cell dynamics and transcriptional programs underlying lipid deposition in highly marbled meat are still unclear. Here, we used Laiwu pigs with high (HLW) or low (LLW) IMF contents to explore the cellular and transcriptional mechanisms underlying lipid deposition in highly-marbled pork by single-nucleus RNA sequencing (snRNA-seq) and bulk RNA sequencing. The HLW group had higher IMF contents but less drip loss than the LLW group. Lipidomics results revelled the changes of overall lipid classes composition (e.g., glycerolipids including triglycerides, diglycerides, and monoglycerides; sphingolipids including ceramides and monohexose ceramide significantly increased) between HLW and LLW groups. SnRNA-seq revealed nine distinct cell clusters, and the HLW group had a higher percentage of adipocytes (1.40% vs. 0.17%) than the LLW group. We identified 3 subpopulations of adipocytes, including PDE4D+/PDE7B+ (in HLW and LLW), DGAT2+/SCD+ (mostly in HLW) and FABP5+/SIAH1+ cells (mostly in HLW). Moreover, we showed that fibro/adipogenic progenitors could differentiate into IMF cells and contribute to 43.35% of adipocytes in mice. In addition, RNA-seq revealed different genes involved in lipid metabolism and fatty acid elongation. Our study provides new insights into the cellular and molecular signatures of marbling formation; such knowledge may facilitate the development of new strategies to increase IMF deposition and the lipo-nutritional quality of high marbled pork.