Intramuscular fat content in meat-producing animals: development, genetic and nutritional control, and identification of putative markers

Improving traceability and quality control in the red-meat industry through computer vision-driven physical meat feature tracking

Current traceability systems rely heavily on external markers which can be altered or tampered with. We hypothesized that the unique intramuscular fat patterns in beef cuts could serve as natural physical identifiers for traceability, while simultaneously providing information about quality attributes. To test our hypothesis, we developed a comprehensive dataset of 38,528 high-resolution beef images from 602 steaks with annotations from human grading and ingredient analysis. Using this dataset, we developed a quality prediction module based on the EfficientNet model, achieving high accuracy in marbling score prediction (96.24% top-1±1, 99.57% top-1±2), breed identification (91.23%), and diet determination (90.90%). Additionally, we demonstrated that internal meat features can be used for traceability, attaining F-1 scores of 0.9942 in sample-to-sample tracing and 0.9479 in sample-to-database tracing. This approach significantly enhances fraud resistance and enables objective quality assessment in the red meat supply chain.

C-type natriuretic peptide regulates lipid metabolism through a NPRB-PPAR pathway in the intramuscular and subcutaneous adipocytes in chickens

Natriuretic peptides (NPs) have an important role in lipid metabolism in skeletal muscle and adipose tissue in animals. C-type natriuretic peptide (CNP) is an important NP, but the molecular mechanisms that underlie its activity are not completely understood. Treatment of intramuscular fat (IMF) and subcutaneous fat (SCF) adipocytes with CNP led to decreased differentiation, promoted proliferation and lipolysis, and increased the expression of natriuretic peptide receptor B (NPRB) mRNA. Silencing natriuretic peptide C (NPPC) had the opposite results in IMF and SCF adipocytes. Transcriptome analysis found 665 differentially expressed genes (DEGs) in IMF adipocytes and 991 in SCF adipocytes. Seven genes in IMF adipocytes (FABP4, APOA1, ACOX2, ADIPOQ, CD36, FABP5, and LPL) and eight genes in SCF adipocytes (ACOX3, ACSL1, APOA1, CPT1A, CPT2, FABP4, PDPK1 and PPARα) are related to fat metabolism. Fifteen genes were found to be enriched in the peroxisome proliferator-activated receptor (PPAR) pathway. Integrated analysis identified 113 intersection genes in IMF and SCF adipocytes, two of which (APOA1 and FABP4) were enriched in the PPAR pathway. In conclusion, CNP may regulated lipid metabolism through the NPRB-PPAR pathway in both IMF and SCF adipocytes, FABP4 and APOA1 may be the key genes that mediated CNP regulation of fat deposition.

Meat Quality of Dairy and Dairy × Beef Steers Reared in Two Production Systems Based on Forages and Semi-Natural Pastures

To safeguard an agricultural landscape with high biodiversity, livestock grazing on semi-natural pastures is crucial, and steers are well suited to such production systems. This study compared meat quality, including technological traits, sensory attributes, and fatty acid composition, of purebred dairy steers (D) and dairy × beef crossbreed steers (C), reared in two distinct production systems. Sixty-four steers (thirty-two per breed type) were included. Half were kept in a production system that had relatively high feed intensity (H), with one grazing summer on semi-natural pastures and slaughtered at 21 months of age. The other half were kept in a production system that had low feed intensity (L), with two grazing summers on semi-natural pastures and slaughtered at 28 months. Colour, water holding capacity, Warner-Bratzler shear force, sensory attributes, and fatty acid profiles were measured on the Musculus longissimus lumborum. Meat from L steers with two grazing seasons was darker (p = 0.003) and contained a higher proportion of unsaturated fatty acids (p = 0.006) than meat from more intensively reared H steers. Meat from C steers was perceived as having a coarser fibre structure (p = 0.022) with an acidic odour (p = 0.040) compared to D steers. Additionally, cooked meat from L steers was evaluated as having a pinker appearance by an analytical sensory panel (p = 0.008). In summary, breed type and production system had no major effect on technological and sensory attributes for forage and pasture-fed steers, but fatty acid composition was improved with more unsaturated lipids in meat from L steers.

Exploring the Dietary Strategies of Coated Sodium Butyrate: Improving Antioxidant Capacity, Meat Quality, Fatty Acid Composition, and Gut Health in Broilers

BACKGROUND/OBJECTIVES

Broiler chickens are excellent animals for protein production and play an essential role in the food industry. The purpose of this study is to investigate the effect of coated sodium butyrate (CSB) on the biochemical indices, antioxidant capacity, meat quality, fatty acid composition, and gut health of Xianju broilers.

METHODS

A total of 192 one-day-old broilers were randomly divided into four treatment groups: the basal diet (CK), the basal diet with 250 mg/kg CSB (CSB250), the basal diet with 500 mg/kg CSB500 (CSB500), and the basal diet with 1000 mg/kg CSB (CSB1000). Each group included six replicates, with eight chicks per replicate.

RESULTS

We found that CSB supplementation in the diets has no function on plasma biochemical indices; however, CSB1000 broilers exhibited markedly elevated plasma TG levels. Furthermore, CSB supplementation at different concentrations significantly increased plasma antioxidase capacity in broilers. Moreover, breast meat supplemented with CSB displayed a higher shear force, pH24h, and inosinic acid content than CK meat. Breast meat of broilers fed CSB1000 showed improved fatty acid composition, evidenced by increased levels of polyunsaturated fatty acids (C16:1, C18:2, C22:4, and C22:6). Moreover, supplementation with CSB1000 optimized the gut microbiota composition, particularly by enhancing the abundance of Firmicutes and the Firmicutes/Bacteroidetes ratio.

CONCLUSIONS

Collectively, these findings offer a basis for the extensive application of CSB as a feed addition to enhance the quality of meat in the broiler sector.

Prediction of marbling score in ribeye quartered at the 5th- 6th rib of French beef using the Q-FOM™ beef assessment camera

In the Meat Standards Australia (MSA) and Guaranteed Global Grading (3G) grading schemes, beef marbling is scored visually in the chiller by accredited graders from 100 to 1190 marble score points in increments of 10. This study aimed to evaluate a hand-held camera (Q-FOM™ Beef) for determining MSA marbling scores of carcasses quartered between the 5th and 6th rib. The carcasses were scored by two accredited graders, including an expert grader (i.e. a more experienced grader). The R2 of correlation between scores of the two graders for 377 carcasses was 0.78 with a RMSE of 47.9. The R2 of correlation between the scores of the expert grader and the Q-FOM™ for 285 carcasses was 0.75 with a RMSE of 44.9. For the grader-to-grader comparison, 75.9 %, 97.1 % and 100 % of the values were within 50, 100 and 200 marbling points, respectively. For the comparison between Q-FOM™ predictions and the expert grader, 78.6 %, 96.8 % and 99.7 % of the values were within 50, 100 and 200 marbling points, respectively. Both between visual graders and the Q-FOM™ against expert grader showed acceptable accuracy performance and fulfilled the accreditation criteria defined by AUS-MEAT in Australia. Additionally, 124 Q-FOM™ images were assessed on-screen by the expert grader. The R2 of correlation between the in-chiller and on-screen MSA marbling scores was 0.78 with a RMSEP of 48.7. Thus, on-screen assessing met requirements for accreditation, and both in-chiller and on-screen visual assessments of MSA marbling score are acceptable inputs for developing a Q-FOM™ Beef marbling model.

Genetic and functional validation of CTSS in regulating intramuscular fat content of Duroc-Landrace-Yorkshire pigs

Intramuscular fat (IMF) is an important meat quality trait and a key target for molecular breeding in pigs. Our previous genome-wide association study identified SNP rs80931414 (A>G) as a significant site associated with IMF content. In this study, we further performed genotyping and association analysis of SNP rs80931414 within a Duroc-Landrace-Yorkshire (DLY) pig population. We found that the IMF content in pigs with AA genotype was significantly higher than that in those with GG genotype. SNP rs80931414 is a genetic variation in CTSS, therefore we hypothesized that CTSS is a candidate gene for IMF content trait in DLY pig and conducted research on gene function of CTSS. Our results indicated that both the mRNA and protein expression levels of CTSS were associated with the expressions of adipogenesis-related genes in skeletal muscle. Overexpression of CTSS promoted adipogenesis in intramuscular preadipocytes, while interference with CTSS inhibited this process. Our findings showed that SNP rs80931414 (A>G), which is a genetic variation in CTSS is related to IMF content and CTSS is a candidate gene for IMF content trait in DLY pig. This study provides the first evidence of the role of CTSS in pig intramuscular preadipocytes and offers insights for the development of breeding strategies aimed at genetically improving IMF content in pork.

The impact of Sarcocystis infection on lamb flavor metabolites and its underlying molecular mechanisms

Introduction

Meat flavor is a critical factor for consumers to evaluate meat quality and a key determinant of its market value. Sarcocystis spp. are widely distributed parasitic protozoa that infect livestock, leading to reduced meat quality, fur, and fiber, and causing significant economic losses. However, most studies focus on the pathogenic mechanisms and epidemiological characteristics of Sarcocystis, with limited research on its specific impact on meat quality and flavor, particularly the underlying molecular regulatory mechanisms.

Methods

This study investigated the effects of Sarcocystis infection on meat flavor and its molecular mechanisms in Tibetan sheep using flavor metabolite analysis and transcriptomic approaches. Tibetan sheep raised under uniform conditions were divided into four groups based on infection severity: normal, low-infection, moderate-infection, and high-infection. Leg muscle samples were collected for flavor metabolite analysis and transcriptome sequencing. Differentially expressed metabolites (DEMs) and differentially expressed genes (DEGs) were identified, and KEGG pathway enrichment analysis was performed to explore how Sarcocystis infection regulates gene expression, affecting lipid, amino acid, and energy metabolism, ultimately altering the production and accumulation of flavor metabolites.

Results

The results showed that Sarcocystis infection significantly altered the composition of flavor metabolites in Tibetan sheep meat as infection severity increased. Phenolic and acidic metabolites were markedly upregulated, intensifying bitterness and sourness, while ketone and lactone metabolites were downregulated, reducing fatty and creamy aromas. Transcriptomic analysis identified 574 DEGs, including upregulated genes such as MAPK12, COX6A2, and RXRA, which are involved in lipid metabolism, fatty acid oxidation, and thermogenesis, and downregulated genes such as COX2, COX3, and ADIPOQ, which are associated with mitochondrial function and energy metabolism. These gene expression changes disrupted lipid and amino acid metabolism, leading to imbalances in the synthesis and accumulation of flavor compounds.

Discussion

This study systematically revealed the significant effects of Sarcocystis infection on the meat flavor of Tibetan sheep and its underlying molecular mechanisms. The findings provide new insights into the metabolic regulation induced by parasitic infection and offer a theoretical basis for mitigating the adverse effects of Sarcocystis infection on meat quality.

Multi-omics integration identifies molecular markers and biological pathways for carcass and meat quality traits in Nellore cattle

Understanding the biological factors that influence carcass and meat quality traits in Nellore cattle requires a clear interpretation of molecular complexity and its variations at different levels of expression. Hence, this study aimed to elucidate the biological control of carcass and meat quality traits in Nellore cattle by integrating genome-wide association study (GWAS), transcriptomic, and proteomic data, focusing on identifying key genes and pathways. GWAS analysis was performed using weighted single-step GBLUP with two iterations. RNA-Seq and proteomic analyses were performed on 24 muscle samples from animals with divergent adjusted phenotypic values (12 for high and 12 for low), for meat tenderness, ribeye area (REA), marbling, and backfat thickness (BFT). The phenotypic values were adjusted for the systematic effects of contemporary groups and age. Differential expression analyses indicated that genes associated with the promotion of growth processes, such as FRZB, IGFBP5 and SEMA6C, exhibited overexpression within the group characterized by higher meat tenderness that inhibits cellular cycles and growth (RTN4 and RB1) were downregulated. Proteins related to heat shock, structural functions, and metabolic regulation also affected the higher meat tenderness group. For marbling, actin-binding proteins, microtubule-forming proteins, and structural proteins were downregulated, while genes involved in fatty acid composition and synthesis were upregulated, with the key genes and transcripts CAND1, ACTN4, FGFR2, and NCOR2 identified. For BFT, neuronal genes, transcripts, and proteins associated with actin cytoskeleton organization and microtubule formation were found. Key genes related to ubiquitination, regulation of energy metabolism, and tissue remodeling were also identified. These findings provide a better understanding of genes, transcripts, proteins, and metabolic pathways involved in carcass and meat quality traits in Nellore cattle.

LC/MS-based lipidomics and transcriptomics reveal lipid diversity and regulatory networks underlying intramuscular fat differences in Xingguo grey geese

Intramuscular fat (IMF) serves as a crucial economic indicator of meat quality. To investigate the heterogeneity of IMF composition and its regulatory mechanisms in Xingguo (XG) geese with varying IMF levels, lipidomics and transcriptomics were utilized. The analysis of lipid profiles revealed that the predominant lipids in the IMF of XG geese were glycerophospholipids (GPs), followed by glycerides (GLs). Interestingly, the low-IMF group exhibited an increase in GPs, specifically phosphatidylethanolamines (PEs) and phosphatidylcholines (PCs), while the high-IMF group showed elevated levels of triacylglycerols (TAGs). Transcriptomic analysis indicated that genes related to extracellular matrices (ECM)-receptor interactions, focal adhesion, mitogen-activated protein kinase (MAPK), and forkhead transcription factors O (FoxO) signaling pathways were upregulated in the low-IMF group. In contrast, genes involved in metabolic processes were more pronounced in the high-IMF group. A comprehensive analysis combining lipidomics and transcriptomics identified CD36, fatty acid-binding protein 5 (FABP5), troponin I2 (TNNI2), and coronin-6 isoform X1 (CORO6) as essential regulators influencing IMF accumulation in XG geese. This research emphasizes the significant lipids, genes, and signaling pathways that play roles in IMF accumulation, providing a theoretical basis for enhancing the meat quality of XG geese.

Influence of finishing systems on sensory characteristics and the mechanisms regulating tenderness formation in the longissimus lumborum of bison bulls

The objective of this study was to characterize the influence of finishing system on the sensory characteristics and mechanisms of tenderness formation in the longissimus lumborum (striploin) of bison bulls. Bison bulls (n = 196) were randomly assigned to one of two finishing treatments at approximately 25 mo of age: 1) Grain-finished (n = 98; placed in an open lot with ad libitum access to prairie hay, alfalfa hay, and whole shell corn prior to slaughter) or 2) Grass-finished (n = 98; bulls allowed to graze native pasture until slaughter). Bulls were harvested at approximately 30 mo of age and striploins were collected. Ultimate pH was recorded, and striploins were fabricated into steaks for assessment of sensory characteristics by consumer and trained sensory panels (steaks aged 14 d), and analysis of Warner-Bratzler shear force (WBSF; steaks aged 4, 7, 14 or 21 d). Additional steaks were aged for 14 d for determination of collagen content and sarcomere length. Proteolysis of desmin and troponin-T was evaluated on samples aged for 4, 7, 14, or 21 d. Consumer panel results indicate that grain-finished steaks had higher ratings for overall liking (P = 0.04) and flavor liking (P < 0.01) whereas off-flavor intensity was increased (P < 0.01) for grass-finished steaks compared to grain-finished steaks. Trained panelists indicated that grass-finished bison steaks had increased (P < 0.01) aroma and flavor intensities compared to grain-finished bison steaks and "ammonia, metallic, and gamey flavors" were associated with the grass-finished treatment. Warner-Bratzler shear force was affected by the interaction of finishing treatment with aging period (P < 0.01). Steaks from the grain-finished bulls became more tender (P ≤ 0.02) as aging time increased from 4 d to 14 d, whereas WBSF of steaks from grass-finished bulls did not differ (P ≥ 0.10) during this period. Steaks from grass-finished bulls were more tender (P ≤ 0.01) than steaks from grain-finished bulls at 4 d and 7 d but treatments were similar (P ≥ 0.61) at 14 and 21 d. Samples from grass-finished bulls had less (P < 0.01) intact desmin compared to grain-finished bulls. This study demonstrates that finishing system influences sensory attributes of steaks from bison bulls and highlights the role of proteolysis as the primary mechanism regulating tenderization of bison.

Identification of key LncRNAs and mRNAs associated with intramuscular fat in pig via WGCNA

BACKGROUND

Intramuscular fat (IMF) not only directly affects the tenderness, juiciness, and overall flavour of meat but also plays a significant role in influencing consumer preferences for pork. Therefore, exploring key biomarkers that influence IMF deposition is highly important for breeding high-quality pork. IMF is a typical quantitative trait that is regulated by the interaction of multiple coding and noncoding RNAs. Traditional differential analysis methods typically focus on individual genes, making it difficult to identify key genes and their underlying mechanisms accurately. Weighted gene coexpression network analysis (WGCNA) is an efficient and accurate method for identifying and characterizing key pathways and genes associated with complex traits. Therefore, the aim of this study was to construct an mRNA‒lncRNA coexpression network related to IMF using WGCNA to explore and identify potential candidate genes that influence IMF in pigs.

RESULTS

Full-length transcriptome sequencing was performed on 31 220-day-old Jiangquan black pigs raised in the same environment, and a gene expression matrix comprising 25,609 genes was constructed. Nine coexpression modules were identified through WGCNA, with the number of genes in these modules ranging from 33 to 3648. The magenta module (corr = 0.7, P < 0.01) and the turquoise module (corr = -0.77, P < 0.01) were significantly associated with IMF deposition. Hub genes in each module were identified on the basis of the screening criteria of GS > 0.4 and MM > 0.8. Combined with enrichment analysis and protein‒protein interaction (PPI) analysis, 18 key mRNAs potentially related to IMF were selected: CRKL, CBL, PDGFRB, DOCK1, YWHAH, HSP90AB1, LOC100524873, NDUFA1, NDUFA11, NDUFA12, NDUFA2, NDUFAB1, NDUFB10, NDUFB3, NDUFB7, NDUFS5, NDUFS6, and UQCR10. To explore the regulatory role of lncRNAs in the process of IMF deposition, we constructed an lncRNA‒mRNA‒pathway network on the basis of the relationships between lncRNAs and key mRNAs, as well as the results of Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. This network includes four key lncRNAs (TGOLN2, LOC100521518, LOC100524915, and LOC100622481) and predicts the potential mechanisms by which lncRNAs regulate IMF deposition.

CONCLUSIONS

Through WGCNA, enrichment analysis, and PPI analysis, 18 mRNAs and four lncRNAs potentially involved in IMF deposition were identified, and the lncRNA regulatory pathways were preliminarily explored. Our findings provide new insights into the regulatory mechanisms of pig IMF deposition and lay the foundation for further exploration of the molecular mechanisms underlying pig fat deposition.

Effect of different Lys/Met ratios in a low-protein diet on the meat quality of Tibetan sheep: A transcriptomics- and metabolomics-based analysis

This study integrated the the effects of dietary Lys/Met ratio in a low protein diet on the meat quality in Tibetan sheep. A total of 90 weaned Tibetan sheep, 2 months old with initial weight of 15.37 ± 0.92 kg were randomly divided into 3 treatments, which were supplemented with Lys/Met ratio at 3 (LP-H), 2 (LP-M), and 1 (LP-L) in the basal diet (10 % crude protein), respectively. After slaughter (150 days of age), the growth performances and meat quality of longissimus dorsi muscle were evaluated. The LP-L group showed significantly higher final body weight compared to the LP-M group (P < 0.05). Serum albumin and total protein levels were significantly higher in the LP-L group than in the LP-H group (P < 0.05). Furthermore, meat from the LP-L group had significantly higher protein, calcium, and vitamin E content compared to the LP-M group (P < 0.05). Transcriptomic analysis revealed 3,479 differentially expressed genes enriched in pathways related to muscle growth, energy metabolism, and signaling transduction. Metabolomic analysis identified 771 differential metabolites, significantly enriched in ABC transporters, beta-alanine metabolism, and taste transduction pathways. Integrated analysis highlighted the upregulation of the ABCD4 gene and L-valine metabolite in the LP-L group, contributing to improved phenotypic traits. These findings provide molecular insights into the regulatory mechanisms underlying the effects of dietary Lys/Met ratios on Tibetan sheep meat quality and offer a basis for developing nutritional strategies to enhance premium meat production.

Evaluation of Effect of Dietary Supplementation with Microencapsulated Hydrolyzed Tannins on Growth, Slaughter Performance, Meat Quality, and Lipid Metabolism of Zhongshan Shelducks

This study investigated the effects of microenapsulated hydrolyzed tannins (MHTs) on the growth performance and meat quality of Zhongshan shelducks. A total of 288 healthy Zhongshan shelducks with an average initial weight of 1790.27 ± 0.14 kg were randomly divided into four groups through a 56 d experiment period and were fed a basal diet supplemented with 0 (CON), 400, 800, and 1600 mg/kg MHTs, respectively. Results showed that 400 and 800 mg/kg MHTs improved the final body weight, average daily gain, glutathione peroxidase activity, and total antioxidant capacity compared to CON (p ≤ 0.05). The diet supplemented with 400 mg/kg MHTs decreased shear force and 800 mg/kg MHTs increased the yield of pectoralis major muscle compared to CON (p ≤ 0.05). Dietary MHTs increased inosine monophosphate content and decreased percentage C14:0 content in meat; however, the b*45 min value, 48 h drip loss, and shear force were increased but the percentage intramuscular fat (IMF) content was decreased in pectoralis major muscle with the increase in MHTs (p ≤ 0.05). Compared to CON, 400 and 800 mg/kg MHTs increased the percentage content of IMF, C18:1n-9, C18:2n-6, monounsaturated fatty acids, polyunsaturated fatty acids, and unsaturated fatty acids in pectoralis major muscle (p ≤ 0.05). Furthermore, 400 and 800 mg/kg MHTs improved the lipid metabolism of IMF deposition, fatty acid uptake, and adipogenesis by activating the peroxisome proliferator-activated receptor gamma pathway to regulate fatty acid synthetase and lipoprotein lipase genes. In conclusion, diets supplemented with 400 and 800 mg/kg MHTs could improve growth, meat quality, antioxidant capacity, and lipid metabolism in Zhongshan shelducks.

Identification and Co-expression Analysis of Differentially Expressed LncRNAs and mRNAs Regulate Intramuscular Fat Deposition in Yaks at Two Developmental Stages

Intramuscular fat (IMF) content is a key indicator of yak meat quality. This study aimed to identify lncRNAs that regulate IMF deposition in yaks. Three male calf yaks (3 months) and three male adult yaks (3 years) were used in the current study. After slaughter, the tissue morphology of the longissimus dorsi (LD) muscle was assessed using a cry-sectioning technique and differentially expressed lncRNAs and mRNAs (DELs and DEMs) were identified using RNA-Seq technology. The diameter and volume of fat droplets were significantly larger and bigger, respectively, in adults than in calves (P < 0.001). A total of 37,790 genes and 16,400 lncRNAs that regulate fat deposition were identified. Among them, 2327 mRNAs and 474 lncRNAs were differentially expressed between calves and adult yaks. DEGs stearoyl-CoA desaturase (SCD), fatty acid synthase (FASN), fatty acid binding protein 4 (FABP4) and fibronectin 1 (FN1) and DELs MSTRG.15795.4 and MSTRG.35028.6 were screened. The enrichment and pathway analysis regulated by the DMEs and DELs were predicted. We found significantly enriched biological processes and pathways involved in fat deposition, including the biosynthesis of unsaturated fatty acids, fatty acid biosynthesis, fatty acid elongation, and the mTOR signaling pathway. Co-expression network of the DELs and related genes, including MSTRG.10268.1-placenta associated 8 (PLAC8), MSTRG.16223.1-galectin 3 (LGALS3), MSTRG.34732.1-glycerol-3-phosphate acyltransferase, mitochondrial (GPAM), MSTRG.11907.11-fibroblast growth factor 1 (FGF1), MSTRG.34342.1-lipase A, lysosomal acid type (LIPA), and MSTRG.1667.2-integrin subunit beta 2 (ITGB2) was constructed. RT-qPCR verified the sequence results. The molecular regulatory mechanisms of lncRNAs on intramuscular fat deposition in yak were further explored.

Genetic Parameter Estimates for Carcass and Meat Quality Traits and Their Genetic Associations With Sexual Precocity Indicator Traits in Nellore Cattle

For developing beef cattle breeding programmes, it is essential to understand the genetic basis of economically relevant traits, such as carcass, meat quality and female sexual precocity. However, the direct selection of most of these traits is a challenge for producers because of the high cost and measurement difficulty. Genetic correlation estimates between carcass and meat quality traits obtained after slaughter and sexual precocity indicator traits in Nellore are limited in the literature. Thus, this study aimed to estimate genetic parameters for longissimus muscle area (LMA), backfat thickness (BF), hot carcass weight (HCW), shear force tenderness (SF), marbling score (MARB), intramuscular fat content (IMF), age at first calving (AFC), heifer pregnancy (HP) and scrotal circumference (SC) in Nellore cattle, using pedigree and genomic information. For this, data from 6910 young bulls with phenotypic information for carcass and meat traits, 230,682 for sexual precocity indicator traits, and 17,850 animals genotyped with or imputed to the Illumina Bovine HD BeadChip were used. The (co)variance components and genetic parameters were estimated considering BLUP and single-step GBLUP (ssGBLUP) models via Bayesian inference using the GIBBSF90+ software. The multi-trait animal model included additive and residual genetic effects as random; the fixed effects of contemporary group (for all traits) and date of analysis as classes (for BF, SF and MARB); and the linear effects of age at slaughter (all carcass and meat traits) and age at yearling (YW and SC) as covariates. Heritability estimates ranged from 0.13 to 0.34 for carcass and meat quality traits, and for SC, AFC and HP, were 0.33, 0.07 and 0.29, respectively. Favourable genetic correlations were estimated between YW-HCW (0.79 ± 0.03), YW-LMA (0.28 ± 0.05), YW-SC (0.35 ± 0.03), HCW-LMA (0.44 ± 0.05), HCW-SF (-0.22 ± 0.09), HCW-SC (0.19 ± 0.05), MARB-IMF (0.90 ± 0.07), SF-IMF (-0.20 ± 0.11), BF-MARB (0.29 ± 0.08), BF-IMF (0.22 ± 0.09), BF-AFC (-0.21 ± 0.07) and BF-HP (0.24 ± 0.10). In general, the correlations between carcass traits and those of meat quality were low to moderate. Additionally, carcass and meat quality traits did not exhibit strong genetic correlations with female precocity indicators. So, to achieve significant genetic advances in female sexual indicator traits, carcass composition and meat quality, these traits must compose selection indices for Nellore cattle.

A novel protein encoded by porcine circANKRD17 activates the PPAR pathway to regulate intramuscular fat metabolism

BACKGROUND

Intramuscular fat is an important factor in evaluating pork quality and varies widely among different pig breeds. However, the regulatory mechanism of circular RNAs (circRNAs) in lipid metabolism remains largely unexplored.

RESULTS

We combined circRNA-seq and Ribo-seq data to screen a total of 18 circRNA candidates with coding potential, and circANKRD17 was found to be significantly elevated in the longissimus dorsi muscle of Lantang piglets, with a length of 1,844 nucleotides. Using single-cell sequencing, we identified 477 differentially expressed genes in IMF cells between Lantang and Landrace piglets, with enrichment in the PPAR signaling pathway. These genes included FABP4, FABP5, CPT1A, and UBC, consistent with the high levels of acylcarnitines observed in the longissimus dorsi muscles of the Lantang breed, as determined by lipidomic analysis. Further in vitro and in vivo experiments indicated that circANKRD17 can regulate lipid metabolism through various mechanisms involving the PPAR pathway, including promoting adipocyte differentiation, fatty acid transport and metabolism, triglyceride synthesis, and lipid droplet formation and maturation. In addition, we discovered that circANKRD17 has an open reading frame and can be translated into a novel 571-amino-acid protein that promotes lipid metabolism.

CONCLUSIONS

Our research provides new insights into the role of protein-coding circANKRD17, especially concerning the metabolic characteristics of pig breeds with higher intramuscular fat content.

Effect of intramuscular fat level on carcass composition, physicochemical characteristics, texture, and microstructure of breast muscle of broiler chickens

This research aimed to determine the effect of intramuscular fat (IMF) levels in m. pectoralis major on carcass weight and composition, meat of male broiler chickens. Whole eviscerated necked carcasses of Ross 308 male broiler chickens aged 42 days were purchased from a commercial poultry slaughterhouse. After the carcasses were dissected, m. pectoralis major was sampled to determine their basic chemical composition, physicochemical and sensory characteristics, texture, and microstructural characteristics. The IMF content of the m. pectoralis major evaluated male Ross 308 broiler chickens at 42 days of age ranged from 0.88 % to 4.64 %. The majority (about 66 %) carcasses contained pectoral muscle containing no more than 2.04 % IMF. Male broiler chicken carcasses differed (P < 0.05) in IMF, water, and protein content of m. pectoralis major. Breast muscles of Ross 308 chickens with the highest IMF levels (2.05-4.64 %) had significantly less water and protein compared to those of chickens with the lowest (0.88-1.60 %) and medium (1.61-2.04 %) IMF levels. IMF level had no effect on carcass weight and composition, physicochemical characteristics, texture, and microstructure of m. pectoralis major. To date, there have been no studies determining the effect of IMF level on microstructure and texture traits of m. pectoralis major (except WB shear force) and electrical conductivity in Ross 308 broiler chickens. The results obtained indicate the need for future research in this area with consideration of males and females and research material from multiple sources.

Comparison of the effects of production and processing parameters on the eating quality of lamb

While many separate research studies have investigated the effect of production and processing factors on eating quality of lamb, the relative impact of these parameters has been difficult to ascertain. In this study, the effect of eighteen production and processing factors on the eating quality of Welsh Lamb was compared, using meat from 624 lambs and assessments by 1920 UK consumers. Four experimental trials provided a balanced assessment of production and processing factors: muscle, breed type, lamb gender, ageing, finishing diet, season, carcase hanging and packaging method. The effect of other parameters was assessed using the combined data: farm type, individual farm, liveweight gain, abattoir, slaughter date, carcase weight, carcase conformation, carcase fat grade, age at slaughter, and transport time. The Meat Standards Australia protocol for consumer panels was used to provide a consistent methodology for comparing the effect on palatability of different treatments and factors and the interactions between them. The three factors that had the most significant effect on consumer sensory quality were muscle, season and individual farm. While the differences between muscles are well known, the effects of season within the 1st year and individual farm have not been widely reported. Meat from mid-season lambs received the highest scores for sensory quality while differences in sensory quality between meat from different farms were pronounced and unexplained; further research is needed to evaluate the role of genetics and/or microflora. Younger age and higher intramuscular fat content also gave improved eating quality, with gender and conformation grade having a small effect. Of the postslaughter factors, ageing to 14 or 21 days, gave significantly better eating quality than 7 days ageing, as did hanging "cross-legged" and vacuum packing, compared with Achilles hanging and modified atmosphere packaging, respectively. There was a significant muscle × hanging method interaction, with the greatest effect of "cross-legged" hanging observed in the loin. There was no significant effect of lamb finishing diet, abattoir, preslaughter daily liveweight gain or transportation time on any of the consumer sensory scores. The main factors tested that provide practical scope for improving the eating quality of lamb were ageing of the meat, carcase hanging and meat packaging. If the reasons for inter- and intra-farm differences in lamb quality can be elucidated, this may provide further management tools for improving the quality and consistency of lamb quality.

Effects of intramuscular fat on the flavor of fresh sheep and goat meat: Recent insights into pre-mortem and post-mortem factors

Sheep and goat meat products are becoming increasingly popular among consumers due to their unique flavor derived from intramuscular fat (IMF), which contributes to formation of the distinctive odor. However, there is currently a dearth of reviews on the impact of IMF on the flavor of sheep and goat meat. The present review aims to discuss the relationships between IMF and flavor through lipid composition and fatty acid (FA) distribution, provide an overview of characteristic flavor compounds affecting the flavor of sheep and goat meat, and shed light on the impacts of pre-mortem and post-mortem factors on meat flavor attributed to changes in FAs and flavor compounds. Controlling pre-mortem practices and adjusting post-mortem harvesting methods are key factors in shaping and/or driving the flavor of sheep and goat meat products. This review enhances the comprehensive understanding of the impact of IMF on the flavor of sheep and goat meat.

Replacing yellow maize with Illipe nut (Shorea stenoptera) improves growth performance and meat quality of porker pigs

The effects of incorporating Illipe nut into the diet of pigs, in replacement of yellow maize, on their growth performance and meat quality was investigated in a 60 days feeding trial. Twenty-four male pigs were divided into two treatments and fed diets with 0% (T1) or 15% (T2) Illipe nut inclusion. Feed intake, live weight (LW) and backfat thickness (BFT) were taken and used to calculate average daily feed intake (ADFI), average daily gain (ADG), feed conversion ratio (FCR) and increase in backfat (IBF). At the end of the trial, final LW and BFT were measured. Pigs were then slaughtered and hot carcass weight (HCW), pH45mins, pH24hrs and dressing percentage (DP) were determined. Other analysis, including total moisture, thawing loss (TL), cooking loss (CL) and water holding capacity (WHC), were conducted on pork samples. Nutritional content and fatty acid (FA) composition of pork samples were analyzed, and nutritional indices were calculated. Improvements (P < 0.05) in final LW, ADG, final BFT, IBF and FCR were seen in pigs fed the T2 diet. Additionally, the T2 pork was superior (P < 0.05) in HCW, DP, pH24hrs, TL, CL, total moisture and WHC than T1 pork. The FA composition of T2 pork was also improved, with a higher (P < 0.05) PUFA:SFA ratio, indicating lower SFA and higher PUFA levels than T1 pork. Along with this, T2 pork had lower (P < 0.05) index of atheroginicity (IA) and higher (health promoting index) HPI levels, indicating that the T2 pork is a healthier choice for consumption. These findings indicate that the inclusion of 15% Illipe nut into the diet of porker pigs improved their overall growth performance and meat quality.

Transcriptome and Metabolome Insights into Key Genes Regulating Fat Deposition and Meat Quality in Pig Breeds

Meat quality is a complex trait that exhibits significant variation across pig breeds, and the regulatory mechanisms governing pork meat quality are not fully elucidated. We compared the transcriptomics and metabolomics of the longissimus dorsi (LD) muscle between the Songliao Black Pig (SBP) and Large White × Landrace Pig (LWLDP) to investigate breed-specific differences in meat quality and underlying regulatory pathways. The results showed that SBP meat had a higher marbling score and backfat thickness, a richer color, a lower shear force, and reduced drip loss. Fatty acid (FA) analysis identified 15 significant FAs in the LWLDP, with docosahexaenoic acid (DHA) in the SBP, while amino acid (AA) analysis revealed no breed-based differences. Transcriptome analysis identified 134 upregulated and 362 downregulated genes in the SBP. Protein-protein interaction (PPI) network analysis found 25 key genes, which are associated with muscle development, fat deposition, and overall meat quality, while genes in the insulin signaling pathway, such as PPP1R3B, PPARGC1A, SOCS1, EIF4E, PRKAR2A, PRKAG2, and FASN, play a crucial role in balancing fat metabolism and catabolism. Metabolomic analysis identified 89 upregulated and 10 downregulated metabolites in the SBP, primarily involved in fructose and mannose metabolism, amino acid biosynthesis, nucleotide sugar metabolism, and glucagon signaling pathways. Gene-metabolite association analysis found that the PPP1R3B gene had a strong association with Thr-Leu, Maltol, D-myo-Inositol-4-phosphate, and Fructose-6-phosphate, while MYOG correlated with Mannose-6-phosphate, Fructose-1-phosphate, Mannose-1-phosphate, and Glucose-6-phosphate. In contrast, NR4A3 and PPARGC1A showed a strong negative correlation with most upregulated metabolites. In conclusion, this study identified functional genes, elucidated the mechanisms associated with meat quality traits, and identified gene-metabolite associations involved in energy metabolism, muscle development, and fat deposition, providing valuable insights into the molecular mechanisms that regulate meat quality between pig breeds.

The chicken cecal microbiome alters bile acids and riboflavin metabolism that correlate with intramuscular fat content

Intramuscular fat (IMF) is a key indicator of chicken meat quality and emerging studies have indicated that the gut microbiome plays a key role in animal fat deposition. However, the potential metabolic mechanism of gut microbiota affecting chicken IMF is still unclear. Fifty-one broiler chickens were collected to identify key cecal bacteria and serum metabolites related to chicken IMF and to explore possible metabolic mechanisms. The results showed that the IMF range of breast muscle of Guizhou local chicken was 1.65 to 4.59%. The complexity and stability of ecological network of cecal microbiota in low-IMF chickens were higher than those in high-IMF chickens. Cecal bacteria positively related to IMF were Alistipes, Synergistes and Subdoligranulum, and negatively related to IMF were Eubacterium_brachy_group, unclassified_f_Lachnospiraceae, unclassified_f_Coriobacteriaceae, GCA-900066575, Faecalicoccus, and so on. Bile acids, phosphatidylethanolamine (Pe) 32:1 and other metabolites were enriched in sera of high-IMF chickens versus low-IMF chickens while riboflavin was enriched in sera of low-IMF chickens. Correlation analysis indicated that specific bacteria including Alistipes promote deposition of IMF in chickens via bile acids while the Eubacterium_brachy group, and Coriobacteriaceae promoted formation of riboflavin, glufosinate, C10-dats (tentative), and cilastatin and were not conducive to the IMF deposition.

Ablation of LKB1 gene changes the lipid profiles of goat intramuscular fat and enhances polyunsaturated fatty acids deposition

The content and composition of intramuscular fat (IMF) affect the cooked meat palatability such as tenderness and juiciness. Thus, elucidation of lipid deposition and its composition in goat IMF is necessary. Here, Jianzhou big-ear goats with higher IMF content is associated with lower mRNA level of LKB1 gene, compared with those of Chuannan black goats. Functionally, knockdown of LKB1 promoted intramuscular adipocyte lipid accumulation. Next, LC-MS/MS based pseudo target analysis found that 409 lipids existed in goat intramuscular adipocytes, of which polyunsaturated fatty acids accounted for most lipids. Compared with the control, 78 differential lipids were screened in the siLKB1 group, enriched in the triacylglycerols and fatty acids subclasses. The combined analysis between lipidomic and published transcriptomic data showed that siLKB1 enhanced polyunsaturated fatty acids synthesis through upregulation expression of HACD4. Finally, the promotion of lipid accumulation and polyunsaturated fatty acids synthesis in the LKB1 knockdown cells were partly rescued by ablation of HACD4. Collectively, these data provide a genetic target to produce PUFA enriched functional goat meat and expand new insights into improvement of meat quality.

Neonatal vitamin A but not retinoic acid administration increases intramuscular adipocyte number in sheep by promoting vascularization

This study investigated whether vitamin A (VA) administration during the neonatal stage could increase the number of intramuscular adipocytes in Hu sheep by promoting vascularity. A total of 56 newborn male Hu sheep were divided into four groups and received intramuscular injections of either 0, 7500 IU retinoic acid (RA), 7500 IU VA, or a combination of 7500 IU VA and 5 mg SU5416 (an angiogenic inhibitor), at 1, 7, 14, and 21 days of age. At 15 days of age, 6 sheep from each group were randomly selected and sacrificed for intramuscular adipogenic capacity analysis. The remaining 8 sheep in each group were raised until they were 8 months old. VA-treated sheep exhibited an increase in preadipocytes, elevated expression of adipogenic genes (CCAAT enhancer binding protein alpha [CEBPA] and CCAAT enhancer binding protein beta [CEBPB]) and angiogenic genes (vascular endothelial growth factor A [VEGFA]), and stromal vascular fraction cells in the longissimus dorsi (LD) muscle with enhanced adipogenic capacity (P ＜ 0.05). These effects were entirely negated by SU5416. Upon slaughter, VA increased final weight, carcass weight, and average daily gain (P ＜ 0.05) but did not affect feed intake at 21 to 32 weeks (P = 0.824). VA increased the number of intramuscular adipocytes in the LD and semitendinosus (ST) muscle (P ＜ 0.05) without changing the adipocyte number of the omentum, perirenal and subcutaneous fats (P ＞ 0.05). VA injections also increased intramuscular triglyceride (TG) content (P = 0.016) without changing the omentum fat weight or subcutaneous fat thickness (P ＞ 0.05), but it did increase the perirenal fat weight (P = 0.011). Consistently, SU5416 mitigated the effects of VA on intramuscular TG content and adipocyte count, correlating with a decrease in vascularity. In contrast, RA injections didn't affect the intramuscular fat (P = 0.744) but reduced the TG content of the omentum and perirenal fat (P ＜ 0.05). In conclusion, intramuscular injections of VA but not RA at the neonatal stage improved the growth performance of Hu sheep, increasing the number of intramuscular adipocytes and marbling by promoting angiogenesis.

A New Perspective on Pig Genetics and Breeding: microRNA

microRNA (miRNA) is a class of small non-coding RNA molecules that are widely expressed in organisms and play an important role in the regulation of gene expression at the post-transcriptional level. In recent years, researchers have begun to explore its effects on the development of domestic animals and have begun to think about its potential role in modern molecular breeding. Increasing evidence shows that miRNA play a central role in the regulation of pig fertility, pork product quality and disease resistance. Understanding the physiological mechanism of miRNA will be able to better guide future breeding work. In this paper, we will review the research progress of the function and mechanism of miRNA in combination with the above economic characteristics of pigs. The reported miRNA and their target genes were sorted out to evaluate their potential role in improving economic traits such as pig fertility, meat quality and disease resistance, to provide a reference for modern pig molecular breeding.

IGFBP7 promotes the proliferation and differentiation of primary myoblasts and intramuscular preadipocytes in chicken

Though it is well known that insulin-like growth factor (IGF) binding protein 7 (IGFBP7) plays an important role in myogenesis and adipogenesis in mammals, its impact on the proliferation, differentiation, and lipid deposition in chicken primary myoblasts (CPM) and intramuscular preadipocytes remains unexplored. In the present study, we firstly examined the correlation between SNPs within the genomic sequence of the IGFBP7 gene and carcass and blood chemical traits in a F2 resource population by genetic association analysis, and found that a significant correlation between the SNP (4_49499525) located in the intron region of IGFBP7 and serum high-density lipoproteins (HDL). We then examined the expression patterns of IGFBP7 across different stages of proliferation and differentiation in CPMs and intramuscular preadipocytes via qPCR, and explored the biological functions of IGFBP7 through gain- and loss-of-function experiments and a range of techniques including qPCR, CCK-8, EdU, flow cytometry, Western blot, immunofluorescence, and Oil Red O staining to detect the proliferation, differentiation, and lipid deposition in CPMs and intramuscular preadipocytes. We ascertained that the expression levels of the IGFBP7 gene increased as cell differentiation progresses in CPMs and intramuscular preadipocytes, and that IGFBP7 promotes the proliferation and differentiation of these cells, as well as facilitates intracellular lipid deposition. Furthermore, we investigated the regulatory mechanism of IGFBP7 expression by using co-transfection strategy and dual-luciferase reporter assay, and discovered that the myogenic transcription factors (MRF), myoblast determination factor (MyoD) and myogenin (MyoG), along with the adipocyte-specific transcription factor (TF) CCAAT/enhancer-binding protein α (C/EBPα), can bind to the core transcription activation region of the IGFBP7 promoter located 500 bp upstream from the transcription start site, thereby promoting IGFBP7 transcription and expression. Taken together, our study underscores the role of IGFBP7 as a positive regulator for myogenesis and adipogenesis, while also elucidating the functional and transcriptional regulatory mechanisms of IGFBP7 in chicken skeletal muscle development and intramuscular adipogenesis.

Genotype-by-environment interactions in beef and dairy cattle populations: A review of methodologies and perspectives on research and applications

Modern livestock production systems are characterized by a greater focus on intensification, involving managing larger numbers of animals to achieve higher productive efficiency and animal health and welfare within herds. Therefore, animal breeding programs need to be strategically designed to select animals that can effectively enhance production performance and animal welfare across a range of environmental conditions. Thus, this review summarizes the main methodologies used for assessing the levels of genotype-by-environment interaction (G × E) in cattle populations. In addition, we explored the importance of integrating genomic and phenotypic information to quantify and account for G × E in breeding programs. An overview of the structure of cattle breeding programs is provided to give insights into the potential outcomes and challenges faced when considering G × E to optimize genetic gains in breeding programs. The role of nutrigenomics and its impact on gene expression related to metabolism in cattle are also discussed, along with an examination of current research findings and their potential implications for future research and practical applications. Out of the 116 studies examined, 60 and 56 focused on beef and dairy cattle, respectively. A total of 83.62% of these studies reported genetic correlations across environmental gradients below 0.80, indicating the presence of G × E. For beef cattle, 69.33%, 24%, 2.67%, 2.67%, and 1.33% of the studies evaluated growth, reproduction, carcass and meat quality, survival, and feed efficiency traits, respectively. By contrast, G × E research in dairy cattle populations predominantly focused on milk yield and milk composition (79.36% of the studies), followed by reproduction and fertility (19.05%), and survival (1.59%) traits. The importance of G × E becomes particularly evident when considering complex traits such as heat tolerance, disease resistance, reproductive performance, and feed efficiency, as highlighted in this review. Genomic models provide a valuable avenue for studying these traits in greater depth, allowing for the identification of candidate genes and metabolic pathways associated with animal fitness, adaptation, and environmental efficiency. Nutrigenetics and nutrigenomics are emerging fields that require extensive investigation to maximize our understanding of gene-nutrient interactions. By studying various transcription factors, we can potentially improve animal metabolism, improving performance, health, and quality of products such as meat and milk.

CRISPR-edited, cell-based future-proof meat and seafood to enhance global food security and nutrition

Food security is a major concern due to the growing population and climate change. A method for increasing food production is the use of modern biotechnology, such as cell culture, marker-assisted selection, and genetic engineering. Cellular agriculture has enabled the production of cell-cultivated meat in bioreactors that mimic the properties of conventional meat. Furthermore, 3D food printing technology has improved food production by adding new nutritional and organoleptic properties. Marker-assisted selection and genetic engineering could play an important role in producing animals and crops with desirable traits. Therefore, integrating cellular agriculture with genetic engineering technology could be a potential strategy for the production of cell-based meat and seafood with high health benefits in the future. This review highlights the production of cell-cultivated meat derived from a variety of species, including livestock, birds, fish, and marine crustaceans. It also investigates the application of genetic engineering methods, such as CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein), in the context of cellular agriculture. Moreover, it examines aspects such as food safety, regulatory considerations, and consumer acceptance of genetically engineered cell-cultivated meat and seafood.

Integration of ATAC-Seq and RNA-Seq Reveals VDR-SELENBP1 Axis Promotes Adipogenesis of Porcine Intramuscular Preadipocytes

Intramuscular fat (IMF) content plays a crucial role in determining pork quality. Recent studies have highlighted transcriptional mechanisms controlling adipogenesis in porcine IMF. However, the changes in chromatin accessibility during adipogenic differentiation are still not well understood. In this study, we performed the assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) and transcriptome sequencing (RNA-Seq) analyses on porcine intramuscular preadipocytes to explore their adipogenic differentiation into mature adipocytes. We identified a total of 56,374 differentially accessible chromatin peaks and 4226 differentially expressed genes at day 0 and day 4 during adipogenic differentiation. A combined analysis of the ATAC-seq and RNA-seq data revealed that 1750 genes exhibited both differential chromatin accessibility and differential RNA expression during this process, including selenium-binding protein 1 (SELENBP1), PLIN1, ADIPOQ, and FASN. Furthermore, we found that vitamin D receptor (VDR) could bind to the promoter region of the SELENBP1 gene, activate SELENBP1 transcription, and ultimately promote lipid accumulation during adipogenic differentiation. This study provides a detailed overview of chromatin accessibility and gene expression changes during the adipogenic differentiation of porcine intramuscular preadipocytes. Moreover, we propose a novel regulatory mechanism involving the VDR-SELENBP1 signaling axis in adipogenic differentiation.

Effects of an extra-high slaughter weight and a low-lysine diet on growth and meat quality of finishing gilts

The present study aimed to find out the feasibility of increasing the meat quality of finishing gilts by increasing their slaughter weight (SW) to an extra-high (XH) level and also by using a low-lysine (lys) diet in XH-weight pig production. Twenty-four gilts and eights barrows were divided into four treatments (T) by gender, SW, and diet: T1 (barrow; 116-kg SW; Medium [Med]-lys [0.80%] diet), T2 (gilt; 116-kg SW; Med-lys), T3 (gilt; XH [150 kg] SW; Med-lys), and T4 (gilt; XH SW, Low-lys [0.60%]). Growth performance from 85 kg of body weight to SW was measured only for T3 and T4. All animals were slaughtered at their target SW, followed by physicochemical analyses and sensory evaluation on the Longissimus lumborum muscle (LL). Average daily gain did not differ between T3 and T4. Dressing percentage was greater for T3 vs. T2. Backfat thickness was greater for T1 vs. T2 and T3 vs. T2, not being different between T3 and T4. The LL pH was lower and Warner-Bratzler Shear force value was greater for T3 vs. T2. Other physicochemical measurements including the intramuscular fat content were not different or different narrowly if different at all (p < 0.05) between T3 and T2 or T4, but not between T1 and T2. The percentages of major fatty acids including 16:0, 18:0, 18:1, and 18:2 in LL, which did not differ between T2 and T3, differed between T3 and T4 apparently resulting from a difference in composition of the ingredients of the two diets. The sensory texture score was greater for T3 vs. T2 in fresh LL; in cooked LL, juiciness and umami scores were greater for T3 vs. T2, flavor score being less for T4 vs. T3. The gender effects on physicochemical and sensory pork quality were small, if any. Overall, the meat quality of finishing gilts could be improved by increasing the SW to the XH level, but not by using the Low-lys diet, suggesting that it will be feasible to produce XH-weight market gilts if the increased meat quality can make up for the expected decrease in production efficiency accompanying the increased SW.

A review of emerging technologies, nutritional practices, and management strategies to improve intramuscular fat composition in beef cattle

The flavour, tenderness and juiciness of the beef are all impacted by the composition of the intramuscular fat (IMF), which is a key determinant of beef quality. Thus, enhancing the IMF composition of beef cattle has become a major area of research. Consequently, the aim of this paper was to provide insight and synthesis into the emerging technologies, nutritional practices and management strategies to improve IMF composition in beef cattle. This review paper examined the current knowledge of management techniques and nutritional approaches relevant to cattle farming in the beef industry. It includes a thorough investigation of animal handling, weaning age, castration, breed selection, sex determination, environmental factors, grazing methods, slaughter weight and age. Additionally, it rigorously explored dietary energy levels and optimization of fatty acid profiles, as well as the use of feed additives and hormone implant techniques with their associated regulations. The paper also delved into emerging technologies that are shaping future beef production, such as genomic selection methods, genome editing techniques, epigenomic analyses, microbiome manipulation strategies, transcriptomic profiling approaches and metabolomics analyses. In conclusion, a holistic approach combining genomic, nutritional and management strategies is imperative for achieving targeted IMF content and ensuring high-quality beef production.

Acetate cellulose fibrous scaffold is suitable for cultivated fat production

Fat is an essential component of meat which contributes to its sensory characteristics. Therefore, producing cultivated fat is essential to replicate the texture, flavor, and juiciness of conventional meat. One of the challenges in obtaining cultivated fat is that once adipocytes reach differentiation in culture, they tend to float. In this study, we tested whether immortalized pre-adipocytes could be viable, grow, and differentiate when cultivated onto a fibrous scaffold produced by the electrospun of cellulose acetate. Our results demonstrated that the cells attach, proliferate, colonize, and differentiate into mature adipocytes in the three-dimensional fibrous structure during the culture period. Moreover, when layers of the scaffold containing differentiated cells were stacked, it acquired a characteristic similar to conventional animal fat. Therefore, this research suggests that fibrous scaffolds produced using cellulose acetate are a promising substrate for producing cultivated fat.

Effects of Acorns on Meat Quality and Lipid Metabolism-Related Gene Expression in Muscle Tissues of Yuxi Black Pigs

OBJECTIVES

The aim of this study was to investigate the effects of acorn diets on the composition of fatty acid (FA) and the intramuscular fat (IMF) content in Yuxi black pigs.

METHODS

Ninety Yuxi black pigs with similar body weight (99.60 ± 2.32 kg) were randomly divided into five groups. The control group was fed a basal diet, and the AD20, AD30, AD40, and AD50 groups were fed experimental diets which contained 20%, 30%, 40%, and 50% acorns, respectively. The feeding experiment lasted for 120 days.

RESULTS

The results showed that compared with the control group, the content of SFA in longissimus dorsi and biceps femoris tissues in the AD30 group decreased by 8.57% and 20.10%, and the content of MUFA increased by 5.40% and 15.83%, respectively, while the PUFA content of biceps femoris increased by 5.40% (p < 0.05). Meanwhile, the IMF content of the AD30 group was significantly higher than that of the control group in the longissimus dorsi and biceps femoris. In addition, the mRNA expression levels of the ATGL, PPARγ, and FABP4 genes in longissimus dorsi (p < 0.05) were up-regulated, and HSL were down-regulated (p < 0.05) in the AD30 group. In the biceps femoris of the AD30 group, it was observed that the expression levels of the ACC and FAS genes were up-regulated (p < 0.05), while HSL and ATGL genes were down-regulated (p < 0.05).

CONCLUSIONS

These results demonstrated that the addition of appropriate amounts of acorn to the diet (a 30% acorn diet) could improve the nutritional value of pork.

Transcriptome analysis reveals the effects of Schizochytrium sp. on the meat quality attributes of Tan lambs

Schizochytrium sp., a feed additive, positively affects the quality of animal meat. In this study, the molecular mechanisms through which dietary Schizochytrium sp. affects the meat quality characteristics of Tan lambs were investigated using transcriptomic techniques. The findings demonstrate that the lambs supplemented with Schizochytrium sp. had a larger loin eye area and a higher average daily gain and intramuscular fat content (P < 0.05). They also had lower drip loss (at 24 and 48 h) and shear force (P < 0.05). Further, 745 genes were differentially expressed between lambs supplemented with Schizochytrium and the control group. Moreover, KEGG pathway analysis showed that the ECM-receptor interaction pathway, which is related to muscle generation and intramuscular fat deposition, was significantly enriched in the lambs administered a diet containing Schizochytrium sp. Herein, we identified some pivotal genes linked to muscular system development and lipid metabolism. Thus, using Schizochytrium sp. may boost the meat quality of Tan lambs by modifying the expression of genes related to hub pathways. The results supply a new basis to determine the molecular mechanisms through which Schizochytrium sp. supplementation regulates the meat quality characteristics of sheep.

Relationships between European carcass evaluation and Meat Standards Australia grading scheme applied to young beef cattle

The European carcass grading scheme (EUROP) places large emphasis on meat yield and therefore on quantitative traits such as carcass conformation and superficial fat coverage. However, it falls short in considering sensory properties and consumer satisfaction. In contrast, the Meat Standards Australia (MSA) grading scheme considers, among others, animals' ossification, marbling, and ultimate pH as primary indicators of beef eating quality. This study aims to characterize MSA carcass grading scheme applied to the Italian beef production system, considering its significant role in European beef market. The study involved 3204 Charolais, Limousin, and crossbred young bulls and heifers slaughtered in a commercial Italian abattoir. Data collection spanned a broad range of variables, including animal characteristics, MSA traits, and EUROP carcass grading traits. Regardless of the sex of the animal, no significant relationship was observed between MSA traits and EUROP carcass grading scores. Factors such as sex, age, and arrival season at the fattening unit significantly affected most of MSA traits. Females had significantly higher marbling score, and lower ossification score and hump height than males. Animals imported in autumn and winter had significantly lower marbling score, but similar ossification score compared to those imported in spring and summer. Older females had the highest marbling scores. While further research is needed to assess whether the MSA grading scheme can be adapted to all different European rearing systems, results of this study are a prelude to the potential benefits that the MSA grading scheme can bring to the European beef industry.

A narrative review: 3D bioprinting of cultured muscle meat and seafood products and its potential for the food industry

The demand for meat and seafood products has been globally increasing for decades. To address the environmental, social, and economic impacts of this trend, there has been a surge in the development of three-dimensional (3D) food bioprinting technologies for lab-grown muscle food products and their analogues. This innovative approach is a sustainable solution to mitigate the environmental risks associated with climate change caused by the negative impacts of indiscriminative livestock production and industrial aquaculture. This review article explores the adoption of 3D bioprinting modalities to manufacture lab-grown muscle food products and their associated technologies, cells, and bioink formulations. Additionally, various processing techniques, governing the characteristics of bioprinted food products, nutritional compositions, and safety aspects as well as its relevant ethical and social considerations, were discussed. Although promising, further research and development is needed to meet standards and translate into several industrial areas, such as the food and renewable energy industries. In specific, optimization of animal cell culture conditions, development of serum-free media, and bioreactor design are essential to eliminate the risk factors but achieve the unique nutritional requirements and consumer acceptance. In short, the advancement of 3D bioprinting technologies holds great potential for transforming the food industry, but achieving widespread adoption will require continued innovation, rigorous research, and adherence to ethical standards to ensure safety, nutritional quality, and consumer acceptance.

microRNA Temporal-Specific Expression Profiles Reveal longissimus dorsi Muscle Development in Tianzhu White Yak

As a class of regulatory factors, microRNAs (miRNAs) play an important role in regulating normal muscle development and fat deposition. Muscle and adipose tissues, as major components of the animal organism, are also economically important traits in livestock production. However, the effect of miRNA expression profiles on the development of muscle and adipose tissues in yak is currently unknown. In this study, we performed RNA sequencing (RNA-Seq) on Tianzhu white yak longissimus dorsi muscle tissue obtained from calves (6 months of age, M6, n = 6) and young (30 months of age, M30, n = 6) and adult yak (54 months of age, M54, n = 6) to identify which miRNAs are differentially expressed and to investigate their temporal expression profiles, establishing a regulatory network of miRNAs associated with the development of muscle and adipose. The results showed that 1191 miRNAs and 22061 mRNAs were screened across the three stages, of which the numbers of differentially expressed miRNAs (DE miRNAs) and differentially expressed mRNAs (DE mRNAs) were 225 and 450, respectively. The expression levels of the nine DE miRNAs were confirmed using a reverse transcription quantitative PCR (RT-qPCR) assay, and the trend of the assay results was generally consistent with the trend of the transcriptome profiles. Based on the expression trend, DE miRNAs were categorized into eight different expression patterns. Regarding the expression of DE miRNAs in sub-trends Profile 1 and Profile 2 (p < 0.05), the gene expression patterns were upregulated (87 DE miRNAs). Gene ontology (GO) and Kyoto Encyclopedia of Genes Genomes (KEGG) analyses showed that the identified DE miRNAs and DE mRNAs were enriched in pathway entries associated with muscle and intramuscular fat (IMF) growth and development. On this basis, we constructed a DE miRNA-mRNA interaction network. We found that some DE mRNAs of interest overlapped with miRNA target genes, such as ACSL3, FOXO3, FBXO30, FGFBP4, TSKU, MYH10 (muscle development), ACOX1, FADS2, EIF4E2, SCD1, EL0VL5, and ACACB (intramuscular fat deposition). These results provide a valuable resource for further studies on the molecular mechanisms of muscle tissue development in yak and also lay a foundation for investigating the interactions between genes and miRNAs.

The Use of Horse and Donkey Meat to Enhance the Quality of the Traditional Meat Product (Kaddid): Analysis of Physico-Chemical Traits

The aim of this study was to evaluate the use of horse and donkey meat in the production of kaddid-a traditional dish typically not made with these meats-from a physical and chemical perspective. The results showed that both meats exhibit similar water retention during cooking, contributing to comparable tenderness and juiciness, with no significant differences in pH values, indicating similar quality (p > 0.05). However, their amino acid profiles differ: horse meat contains lower levels of glutamate (p < 0.05), methionine (p < 0.01), isoleucine (p < 0.05), and leucine (p < 0.05), but higher levels of proline (p < 0.05), histidine (p < 0.01), and lysine (p < 0.001) compared to donkey meat. Both meats provide essential amino acids. Horse meat is richer in saturated and monounsaturated fatty acids (32.44% and 39.58%, respectively), while donkey meat has a higher content of polyunsaturated fatty acids (31.51%), with a more favorable PUFA/SFA ratio, suggesting better cardiovascular health benefits. In terms of dried meat, donkey kaddid has a higher protein (17.45 g/100 g) and lower fat content (2.1 g/100 g) compared to horse kaddid (16.7 g/100 g, and 3.5 g/100 g, respectively) (p < 0.05). These findings inform consumer choices and production practices, promoting the use of horse and donkey meat for kaddid production.

The Impact of Genetic and Non-Genetic Factors on Lamb Loin Shear Force

Shear force is commonly used to evaluate tenderness, one of the most crucial eating quality aspects of sheep meat. The effect size of various factors on tenderness is still unknown. Studies have suggested that both genetic and environmental factors contribute to the variation in meat tenderness, and there are possible interactions between these factors. An extensive data set (n = 23,696) was analyzed to examine genetic and non-genetic influences on the shear force at 5 days postmortem (SF5). SF5 was measured on lamb loins (Longissimus lumborum) taken from lambs reared over 12 years at eight sites across Australia. The results showed that all carcass traits had a significant (p < 0.001) impact on SF5, with the largest effect on SF5 associated with intramuscular fat (IMF %) (f = 1035). There was also a significant effect of sex, cold shortening at 18 °C, sire type and cohort on SF5 (p < 0.001), with a large variation observed between the minimum cohort at 15.9 ± 1.5 N and maximum at 51.2 ± 2.1 N. In conclusion, a complex matrix of production, processing and genetic factors impact lamb tenderness as measured by shear force. This experiment helps identify the size of the contribution of these factors towards lamb tenderness, enabling the sheep industry to enhance consumers' satisfaction.

Transcriptome-metabolome reveals the molecular changes in meat production and quality in the hybrid populations of Sichuan white goose

Hybrid breeding has proven to enhance meat quality and is extensively utilized in goose breeding. Nevertheless, there is a paucity of research investigating the molecular mechanisms that underlie the meat quality of hybrid geese. In this study, we employed the Sichuan White Goose as the maternal line for hybridization with the Zhedong White Goose and Tianfu Meat Goose P3 line. We assessed the growth and slaughter meat quality performance of 10-wk-old hybrid offspring in comparison to Sichuan white goose purebred offspring. The results indicate that hybrid geese have significantly improved performance in growth and slaughter meat quality. Furthermore, we conducted a comprehensive analysis of the chest muscles of hybrid offspring through transcriptomics and metabolomics to unravel the effects of hybrid breeding on growth and meat quality. A total of 673 differentially expressed genes (DEGs), and 93 differentially expressed metabolites were identified. The joint analysis highlighted the significant enrichment of DEGs AMPD1, AMPD3, RRM2, ENTPD3, and the metabolite UMP in the nucleotide metabolism pathway. These findings underscore the crucial role of these genetic and metabolic factors in regulating muscle growth and meat quality in hybrid populations.

Activation of skeletal carbohydrate-response element binding protein (ChREBP)-mediated de novo lipogenesis increases intramuscular fat content in chickens

The intracellular lipids in muscle cells of farm animals play a crucial role in determining the overall intramuscular fat (IMF) content, which has a positive impact on meat quality. However, the mechanisms underlying the deposition of lipids in muscle cells of farm animals are not yet fully understood. The purpose of this study was to determine the roles of carbohydrate-response element binding protein (ChREBP) and fructose in IMF deposition of chickens. For virus-mediated ChREBP overexpression in tibialis anterior (TA) muscle of chickens, seven 5-d-old male yellow-feather chickens were used. At 10 d after virus injection, the chickens were slaughtered to obtain TA muscles for analysis. For fructose administration trial, sixty 9-wk-old male yellow-feather chickens were randomly divided into 2 groups, with 6 replicates per group and 5 chickens per replicate. The chickens were fed either a basal diet or a basal diet supplemented with 10% fructose (purity ≥ 99%). At 4 wk later, the chickens were slaughtered, and breast and thigh muscles were collected for analysis. The results showed that the skeletal ChREBP mRNA levels were positively associated with IMF content in multiple species, including the chickens, pigs, and mice (P < 0.05). ChREBP overexpression increased lipid accumulation in both muscle cells in vitro and the TA muscles of mice and chickens in vivo (P < 0.05), by activation of the de novo lipogenesis (DNL) pathway. Moreover, activation of ChREBP by dietary fructose administration also resulted in increased IMF content in mice and notably chickens (P < 0.05). Furthermore, the lipidomics analysis revealed that ChREBP activation altered the lipid composition of chicken IMF and tented to improve the flavor profile of the meat. In conclusion, this study found that ChREBP plays a pivotal role in mediating the deposition of fat in chicken muscles in response to fructose-rich diets, which provides a novel strategy for improving meat quality in the livestock industry.

MiR-196a Promotes Lipid Deposition in Goat Intramuscular Preadipocytes by Targeting MAP3K1 and Activating PI3K-Akt Pathway

Meat quality in goats is partly determined by the intramuscular fat (IMF) content, which is associated with the proliferation and differentiation of intramuscular preadipocytes. Emerging studies have suggested that miRNA plays a crucial role in adipocyte proliferation and differentiation. In our recent study, we observed the expression variations in miR-196a in the longissimus dorsi muscle of Jianzhou goats at different ages. However, the specific function and underlying mechanism of miR-196a in IMF deposition are still unclear. This study demonstrated that miR-196a significantly enhanced adipogenesis and apoptosis and reduced the proliferation of preadipocytes. Subsequently, RNA-seq was employed to determine genes regulated by miR-196a, and 677 differentially expressed genes were detected after miR-196a overexpression. The PI3K-Akt pathway was identified as activated in miR-196a regulating intramuscular adipogenesis via Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and further verified via Western blot and rescue assays. Lastly, using RT-qPCR, Western blot, dual-luciferase, and rescue assays, we found that miR-196a promoted adipogenesis and suppressed the proliferation of intramuscular preadipocytes by the downregulation of MAP3K1. In summary, these results suggest that miR-196a regulates IMF deposition by targeting MAP3K1 and activating the PI3K-Akt pathway and provide a theoretical foundation for improving goat meat quality through molecular breeding.

Leveraging Functional Genomics for Understanding Beef Quality Complexities and Breeding Beef Cattle for Improved Meat Quality

Consumer perception of beef is heavily influenced by overall meat quality, a critical factor in the cattle industry. Genomics has the potential to improve important beef quality traits and identify genetic markers and causal variants associated with these traits through genomic selection (GS) and genome-wide association studies (GWAS) approaches. Transcriptomics, proteomics, and metabolomics provide insights into underlying genetic mechanisms by identifying differentially expressed genes, proteins, and metabolic pathways linked to quality traits, complementing GWAS data. Leveraging these functional genomics techniques can optimize beef cattle breeding for enhanced quality traits to meet high-quality beef demand. This paper provides a comprehensive overview of the current state of applications of omics technologies in uncovering functional variants underlying beef quality complexities. By highlighting the latest findings from GWAS, GS, transcriptomics, proteomics, and metabolomics studies, this work seeks to serve as a valuable resource for fostering a deeper understanding of the complex relationships between genetics, gene expression, protein dynamics, and metabolic pathways in shaping beef quality.

Evaluation of carcass traits, meat quality and the expression of lipid metabolism-related genes in different slaughter ages and muscles of Taihang black goats

OBJECTIVE

This study was conducted to investigate the effect of slaughter age on carcass traits, meat quality, and the relative mRNA levels of lipid metabolism-related genes in different muscles of Taihang black goats.

METHODS

In this study, the triceps brachii (TB), longissimus dorsi (LD) and gluteus (GL) muscles of 15 grazing Taihang black goats slaughtered at the age of 2, 3, and 4 (designated as 2-year-old, 3-year-old, and 4-year-old, respectively) were collected. The differences in carcass shape, meat quality, amino acid composition and lipid metabolism gene expression among Taihang black goats of different ages and from different plant parts were compared.

RESULTS

Compared with goats at other ages, goats slaughtered at the age of 4 had greater live and carcass weights, meat weights, bone weights and skin areas (p<0.05). LD in the 4-years-old had the lowest cooking loss and moisture content. The crude protein content in the LD of 2-year-old was significantly greater than that in the other age group, and at the age of 2, the LD had the highest crude protein content than TB and GL. The highest fat content was in LD, followed by TB, for goats slaughtered at the age of 4. Eight out of 9 essential amino acids had higher content in the TB compared with other muscles, regardless of age. The total essential amino acid content was highest in the 4-year-old and lowest in the GL muscle at the age of 3. The sterol regulatory element-binding protein-1c (SREBP-1c) and adipose triglyceride lipase (ATGL) genes were significantly more abundant in the TB muscle than in the other muscles for goats slaughtered at the age of 2. At the age of 4, the ATGL and peroxisome proliferator-activated receptor γ (PPARγ) genes were significantly more abundant in the GL than in the LD, while the fatty acid synthase (FAS) genes were significantly less abundant in the GL than in the other muscles. Similarly, compared with those in goats of other ages, the relative mRNA expression levels of the FAS and heart-type fatty acid binding protein (H-FABP) genes in goats slaughtered at the age of 4 were the highest, and the relative mRNA expression of the PPARγ gene was the lowest (p<0.05). The relative mRNA expression of the H-FABP and FAS genes was positively correlated with the intramuscular fat (IMF) content, while the relative mRNA expression levels of the PPARγ and ATGL genes was negatively correlated with the IMF content.

CONCLUSION

Overall, a better nutritional value was obtained for TB from 4-year-old goats, in which the total essential amino acid and fat contents were greater than those of other muscles. The comprehensive action of lipid metabolism genes was consistent with that of the IMF content, among which the FAS, H-FABP, PPARγ, and ATGL genes had positive and negative effects on the process of IMF deposition in Taihang black goats.

LEP inhibits intramuscular adipogenesis through the AMPK signaling pathway in vitro

Leptin can indirectly regulate fatty-acid metabolism and synthesis in muscle in vivo and directly in incubated muscle ex vivo. In addition, non-synonymous mutations in the bovine leptin gene (LEP) are associated with carcass intramuscular fat (IMF) content. However, the effects of LEP on lipid synthesis of adipocytes have not been clearly studied at the cellular level. Therefore, this study focused on bovine primary intramuscular preadipocytes to investigate the effects of LEP on the proliferation and differentiation of intramuscular preadipocytes, as well as its regulatory mechanism in lipid synthesis. The results showed that both the LEP and leptin receptor gene (LEPR) were highly expressed in IMF tissues, and their mRNA expression levels were positively correlated at different developmental stages of intramuscular preadipocytes. The overexpression of LEP inhibited the proliferation and differentiation of intramuscular preadipocytes, while interference with LEP had the opposite effect. Additionally, LEP significantly promoted the phosphorylation level of AMPKα by promoting the protein expression of CAMKK2. Meanwhile, rescue experiments showed that the increasing effect of AMPK inhibitors on the number of intramuscular preadipocytes was significantly weakened by the overexpression of LEP. Furthermore, the overexpression of LEP could weaken the promoting effect of AMPK inhibitor on triglyceride content and droplet accumulation, and prevent the upregulation of adipogenic protein expression (SREBF1, FABP4, FASN, and ACCα) caused by AMPK inhibitor. Taken together, LEP acted on the AMPK signaling pathway by regulating the protein expression of CAMKK2, thereby downregulating the expression of proliferation-related and adipogenic-related genes and proteins, ultimately reducing intramuscular adipogenesis.

Unraveling the flavor profiles of chicken meat: Classes, biosynthesis, influencing factors in flavor development, and sensory evaluation

Chicken is renowned as the most affordable meat option, prized by consumers worldwide for its unique flavor, and universally recognized for its essential savory flavor. Current research endeavors are increasingly dedicated to exploring the flavor profile of chicken meat. However, there is a noticeable gap in comprehensive reviews dedicated specifically to the flavor quality of chicken meat, although existing reviews cover meat flavor profiles of various animal species. This review aims to fill this gap by synthesizing knowledge from published literature to describe the compounds, chemistry reaction, influencing factors, and sensory evaluation associated with chicken meat flavor. The flavor compounds in chicken meat mainly included water-soluble low-molecular-weight substances and lipids, as well as volatile compounds such as aldehydes, ketones, alcohols, acids, esters, hydrocarbons, furans, nitrogen, and sulfur-containing compounds. The significant synthesis pathways of flavor components were Maillard reaction, Strecker degradation, lipid oxidation, lipid-Maillard interaction, and thiamine degradation. Preslaughter factors, including age, breed/strain, rearing management, muscle type, and sex of chicken, as well as postmortem conditions such as aging, cooking conditions, and low-temperature storage, were closely linked to flavor development and accounted for the significant differences observed in flavor components. Moreover, the sensory methods used to evaluate the chicken meat flavor were elaborated. This review contributes to a more comprehensive understanding of the flavor profile of chicken meat. It can serve as a guide for enhancing chicken meat flavor quality and provide a foundation for developing customized chicken products.

Single-nucleus RNA sequencing and lipidomics reveal characteristics of transcriptional and lipid composition in porcine longissimus dorsi muscle

BACKGROUND

Global per capita meat consumption continues to rise, especially pork. Meat quality is influenced by the content of intramuscular fat (IMF) as a key factor. The longissimus dorsi muscle of Dahe pigs (DHM, IMF: 7.98% ± 1.96%) and Dahe black pigs (DHBM, IMF: 3.30% ± 0.64%) was studied to explore cellular heterogeneity and differentially expressed genes (DEGs) associated with IMF deposition using single-nucleus RNA sequencing (snRNA-seq). The lipid composition was then analyzed using non-targeted lipidomics.

RESULTS

A total of seven cell subpopulations were identified, including myocytes, fibroblast/fibro/adipogenic progenitors (FAPs), satellite cells, endothelial cells, macrophages, pericytes, and adipocytes. Among them, FAPs and adipocytes were more focused because they could be associated with lipid deposition. 1623 DEGs in the FAPs subpopulation of DHBM were up-regulated compared with DHM, while 1535 were down-regulated. These DEGs enriched in the glycolysis/gluconeogenesis pathway. 109 DEGs were up-regulated and 806 were down-regulated in the adipocyte subpopulation of DHBM compared with DHM, which were mainly enriched in the PPAR signaling pathway and fatty acid (FA) biosynthesis. The expression level of PPARG, ABP4, LEP, and ACSL1 genes in DHM was higher than that in DHBM. Lipidomics reveals porcine lipid composition characteristics of muscle tissue. A total of 41 lipid classes and 2699 lipid species were identified in DHM and DHBM groups. The top ten relative peak areas of lipid classes in DHM and DHBM were triglyceride (TG), phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), diglyceride (DG), cardiolipin (CL), ceramides (Cer), Simple Glc series (Hex1Cer), sphingomyelin (phSM), and phosphatidylinositol (PI). The relative peak areas of 35 lipid species in DHM were lower than DHBM, and 28 lipid species that were higher. There was a significant increase in the TG fatty acyl chains C6:0, C17:0, and C11:4, and a significant decrease in C16:0, C18:1, C18:2, and C22:4 in DHBM (p < 0.05).

CONCLUSIONS

C16:0 FA may downregulate the expression level of PPARG gene, which leads to the downregulation of fat metabolism-related genes such as ACSL, PLIN2, and FABP4 in DHBM compared with DHM. This may be the reason that the lipid deposition ability of Dahe pigs is stronger than that of Dahe black pigs, which need further investigation.

Polymorphisms of the SCD1 Gene and Its Association Analysis with Carcass, Meat Quality, Adipogenic Traits, Fatty Acid Composition, and Milk Production Traits in Cattle

Stearoyl-CoA desaturase-1 (SCD1) is a key enzyme in the biosynthesis of monounsaturated fatty acids and is considered a candidate gene for improving milk and meat quality traits. Sanger sequencing was employed to investigate the genetic polymorphism of the fifth exon and intron of bovine SCD1, revealing four SNPs, g.21272246 A>G, g.21272306 T>C, g.21272422 C>T, and g.21272529 A>G. Further variance analysis and multiple comparisons were conducted to examine the relationship between variation sites and economic traits in Chinese Simmental cattle, as well as milk production traits in Holstein cows. The findings revealed these four loci exhibited significant associations with carcass traits (carcass weight, carcass length, backfat thickness, and waist meat thickness), meat quality (pH value, rib eye area, and marbling score), adipogenic traits (fat score and carcass fat coverage rate), and fatty acid composition (linoleic acid and α-linolenic acid). Furthermore, these loci were additionally found to be significantly associated with average milk yield and milk fat content in cows. In addition, a haplotype analysis of combinations of SNPs showed that H2H3 has a significant association with adipogenic traits and H2H2 was associated with higher levels of linoleic acid and α-linolenic acid than the other combinations. These results suggest that the four SNPs are expected to be prospective genetic markers for the above economic traits. In addition, the function of SNPs in exon 5 of SCD1 on gene expression and protein structure needs to be explored in the future.

Unraveling the Genetic Foundations of Broiler Meat Quality: Advancements in Research and Their Impact

As societal progress elevates living standards, the focus on meat consumption has shifted from quantity to quality. In broiler production, optimizing meat quality has become paramount, prompting efforts to refine various meat attributes. Recent advancements in sequencing technologies have revealed the genome's complexity, surpassing previous conceptions. Through experimentation, numerous genetic elements have been linked to crucial meat quality traits in broiler chickens. This review synthesizes the current understanding of genetic determinants associated with meat quality attributes in broilers. Researchers have unveiled the pivotal insights detailed herein by employing diverse genomic methodologies such as QTL-based investigations, candidate gene studies, single-nucleotide polymorphism screening, genome-wide association studies, and RNA sequencing. These studies have identified numerous genes involved in broiler meat quality traits, including meat lightness (COL1A2 and ACAA2), meat yellowness (BCMO1 and GDPD5), fiber diameter (myostatin and LncIRS1), meat pH (PRDX4), tenderness (CAPN1), and intramuscular fat content (miR-24-3p and ANXA6). Consequently, a comprehensive exploration of these genetic elements is imperative to devise novel molecular markers and potential targets, promising to revolutionize strategies for enhancing broiler meat quality.

Preliminary genetic parameter estimates of meat quality traits in Hu sheep

Because substantial numbers of Chinese consumers are prepared to pay for tender and quality lamb, meat quality traits are becoming more relevant for breeding programs for Chinese sheep breeds. The current study estimated heritabilities and genetic correlations for 13 meat quality traits recorded on lamb loins from Hu sheep. Heritability estimates ranged from 0.04 ± 0.06 for meat redness at 45 min to 0.57 ± 0.10 for drip loss, with most of the meat quality traits having moderate heritabilities. Positive genetic correlations were observed among meat color traits. Intramuscular fat (IMF) was genetically correlated with most meat quality traits, indicating that increasing IMF can favor meat pH, color, and tenderness, but would lead to increased cooking loss. Direct selection to increase IMF of loins is recommended to be included in breeding programs for Hu sheep, as it was more efficient than indirect selection on the other meat quality traits. The genetic parameters presented in this preliminary study provide valuable genetic information needed to design a breeding program aimed at improving the quality of lamb meat from Hu sheep.