Identification of circRNA-associated ceRNA networks in the longissimus dorsi of yak under different feeding systems

BACKGROUND

Yaks (Bos grunniens), prized for their ability to thrive in high-altitude environments, are indispensable livestock in the plateau region. Modifying their feeding systems holds significant promise for improving their growth and meat quality. Tenderness, a key determinant of yak meat quality and consumer appeal, is demonstrably influenced by dietary regimen. Indoor feeding regimes have been shown to enhance tenderness by lowering shear stress and optimizing pH values. CircRNAs, well-known modulators of circulatory function, also play a crucial role in skeletal muscle development across various animal species. However, their functional significance in yak skeletal muscle remains largely unexplored.

RESULTS

In this study, we identified a total of 5,534 circRNAs within the longissimus dorsi muscle, and we found 51 differentially expressed circRNAs (20 up-regulated and 31 down-regulated) between the two feeding groups. Constructing a comprehensive ceRNA network illuminated intricate regulatory mechanisms, with PGP and circRNA_0617 converging on bta-miR-2285q, mirrored by KLF15/circRNA_0345/bta-miR-20b and CTSF/circRNA_0348/bta-miR-146a. These findings shed light on the potential of circRNAs to influence yak muscle development and meat quality, offering valuable insights for future research.

CONCLUSIONS

This investigation unraveled a complex interaction network between circRNAs、mRNAs and miRNAs in yak skeletal muscle. We further elucidated the target genes regulated by these target genes within the network, offering valuable insights into the potential regulatory mechanisms governing muscle development and meat quality-related traits in yaks.

Comparative transcriptome and proteome analyses of the longissimus dorsi muscle for explaining the difference between donkey meat and other meats

Domestic donkeys (Equus asinus) have been maintained mainly for service purposes in the past. Nowadays, there is an increasing interest in donkey milk and meat production in several countries, including China. Donkey meat is highly consumed because of its nutritional value and unique flavor. However, genomic studies on donkey meat are limited. Therefore, in this study, we aimed to examine the molecular difference of longissimus dorsi muscles of donkey, cow, and goat. RNA sequencing and Proteome sequencing technology were used to analyze the transcriptome and proteome of the longissimus dorsi muscle of donkey, cow, and goat. A total of 1338 and 1780 differentially expressed genes (DEGs) were identified in donkey meat compared with that in cow and goat meat, respectively. Most of the DEGs were involved in biological processes, including small GTPase-mediated signal transduction, protein ubiquitination, protein glycosylation, and MAP kinase tyrosine/serine/threonine phosphatase activity. Additionally, 764 and 1024 differentially expressed proteins (DEPs) were identified in cow vs. donkey, and goat vs. donkey, respectively; these DEPs were mainly involved in metabolism. Genetic variation and regulatory factors can combine as a database to provide more valuable molecular information for further analysis.

Identification of genomic regions, genetic variants and gene networks regulating candidate genes for lipid metabolism in pig muscle

The intramuscular fat content and fatty acid composition of porcine meat have a significant impact on its quality and nutritional value. This research aimed to investigate the expression of 45 genes involved in lipid metabolism in the longissimus dorsi muscle of three experimental pig backcrosses, with a 25% of Iberian background. To achieve this objective, we conducted an expression Genome-Wide Association Study (eGWAS) using gene expression levels in muscle measured by high-throughput real-time qPCR for 45 target genes and genotypes from the PorcineSNP60 BeadChip or Axiom Porcine Genotyping Array and 65 single nucleotide polymorphisms (SNPs) located in 20 genes genotyped by a custom-designed Taqman OpenArray in a cohort of 354 animals. The eGWAS analysis identified 301 eSNPs associated with 18 candidate genes (ANK2, APOE, ARNT, CIITA, CPT1A, EGF, ELOVL6, ELOVL7, FADS3, FASN, GPAT3, NR1D2, NR1H2, PLIN1, PPAP2A, RORA, RXRA and UCP3). Three cis-eQTL (expression quantitative trait loci) were identified for GPAT3, RXRA, and UCP3 genes, which indicates that a genetic polymorphism proximal to the same gene is affecting its expression. Furthermore, 24 trans-eQTLs were detected, and eight candidate regulatory genes were located in these genomic regions. Additionally, two trans-regulatory hotspots in Sus scrofa chromosomes 13 and 15 were identified. Moreover, a co-expression analysis performed on 89 candidate genes and the fatty acid composition revealed the regulatory role of four genes (FABP5, PPARG, SCD, and SREBF1). These genes modulate the levels of α-linolenic, arachidonic, and oleic acids, as well as regulating the expression of other candidate genes associated with lipid metabolism. The findings of this study offer novel insights into the functional regulatory mechanism of genes involved in lipid metabolism, thereby enhancing our understanding of this complex biological process.

Expression profile and bioinformatics analysis of circRNA and its associated ceRNA networks in longissimus dorsi from Lufeng cattle and Leiqiong cattle

This paper aims to explore the role of circRNA expression profiles and circRNA-associated ceRNA networks in the regulation of myogenesis in the longissimus dorsi of cattle breeds surviving under subtropical conditions in southern China by RNA sequencing and bioinformatics analysis. It also aims to provide comprehensive understanding of the differences in muscle fibers in subtropical cattle breeds and to expand the knowledge of the molecular networks that regulate myogenesis. With regard to meat quality indicators, results showed that the longissimus dorsi of LQC had lower pH (P < 0.0001), lower redness (P < 0.01), lower shear force (P < 0.05), and higher brightness (P < 0.05) than the longissimus dorsi of LFC. With regard to muscle fiber characteristics, the longissimus dorsi of LQC had a smaller diameter (P < 0.0001) and higher density of muscle fibers (P < 0.05). The analysis results show that the function of many circRNA-targeted mRNAs was related to myogenesis and metabolic regulation. Furthermore, in the analysis of the function of circRNA source genes, we hypothesized that btacirc_00497 and btacirc_034497 may regulate the function and type of myofibrils by affecting the expression of MYH6, MYH7, and NEB through competitive linear splicing.

Effects of Shear Stress Waves on Meat Tenderness: Ultrasonoporation

Meat is an important part of the food pyramid in Mexico, to such an extent that it is included in the basic food basket. In recent years, there has been great interest in the application of so-called emerging technologies, such as high-intensity ultrasound (HIU), to modify the characteristics of meat and meat products. The advantages of the HIU in meat such as pH, increased water-holding capacity, and antimicrobial activity are well documented and conclusive. However, in terms of meat tenderization, the results are confusing and contradictory, mainly when they focus on three HIU parameters: acoustic intensity, frequency, and application time. This study explores via a texturometer the effect of HIU-generated acoustic cavitation and ultrasonoporation in beef (m. Longissimus dorsi). Loin-steak was ultrasonicated with the following parameters: time t_HIU = 30 min/each side; frequency f_HIU = 37 kHz; acoustic intensity I_HIU = ~6, 7, 16, 28, and 90 W/cm². The results showed that acoustic cavitation has a chaotic effect on the loin-steak surface and thickness of the rib-eye due to Bjerknes force, generating shear stress waves, and acoustic radiation transmittance via the internal structure of the meat and the modification of the myofibrils, in addition to the collateral effect in which the collagen and pH generated ultrasonoporation. This means that HIU can be beneficial for the tenderization of meat.

Transcriptome-wide analysis of RNA m6A methylation regulation of muscle development in Queshan Black pigs

BACKGROUND

N⁶-methyladenosine (m⁶A) refers to the methylation modification of N⁶ position of RNA adenine, a dynamic reversible RNA epigenetic modification that plays an important regulatory role in a variety of life processes. In this study, we used MeRIP-Seq and RNA-Seq of the longissimus dorsi (LD) muscle of adult (QA) and newborn (QN) Queshan Black pigs to screen key genes with m⁶A modification involved in muscle growth by bioinformatics analysis.

RESULTS

A total of 23,445 and 25,465 m⁶A peaks were found in the whole genomes of QA and QN, respectively. Among them, 613 methylation peaks were significantly different (DMPs) and 579 genes were defined as differentially methylated genes (DMGs). Compared with the QN group, there were 1,874 significantly differentially expressed genes (DEGs) in QA group, including 620 up-regulated and 1,254 down-regulated genes. In order to investigate the relationship between m⁶A and mRNA expression in the muscle of Queshan Black pigs at different periods, a combined analysis of MeRIP-Seq and RNA-Seq showed that 88 genes were significantly different at both levels. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes results showed that DEGs and DMGs were mainly involved in skeletal muscle tissue development, FoxO signaling pathway, MAPK signaling pathway, insulin signaling pathway, PI3K-Akt signaling pathway, and Wnt signaling pathway. Four DEGs (IGF1R, CCND2, MYOD1 and FOS) and four DMGs (CCND2, PHKB, BIN1 and FUT2), which are closely related to skeletal muscle development, were selected as candidate genes for verification, and the results were consistent with the sequencing results, which indicated the reliability of the sequencing results.

CONCLUSIONS

These results lay the foundation for understanding the specific regulatory mechanisms of growth in Queshan Black pigs, and provide theoretical references for further research on the role of m⁶A in muscle development and breed optimization selection.

Estrogen-mediated oar-miR-485-5p targets PPP1R13B to regulate myoblast proliferation in sheep

Ovaries are important endocrine organs in female animals that secrete various steroid hormones, which are involved in multiple physiological functions. Estrogen, one of the hormones secreted by ovaries, is essential for the overall maintenance of muscle growth and development. However, the molecular mechanisms that affect muscle growth and development in sheep following ovariectomy remain unclear. In this study, we identified 1662 differentially expressed mRNAs (DEGs) and 40 differentially expressed miRNAs (DEMs) in sheep that underwent ovariectomy compared with those that underwent sham surgery. A total of 178 DEG-DEM pairs were negatively correlated. GO and KEGG analysis showed that PPP1R13B was involved in the PI3K-Akt signaling pathway, which was essential for muscle development. Using in vitro experiments, we examined the effect of PPP1R13B on myoblast proliferation and found that overexpression or inhibition of PPP1R13B increased or decreased the expression of myoblast proliferation markers, respectively. PPP1R13B was identified as a functional downstream target of miR-485-5p. Our results suggested that miR-485-5p promoted myoblast proliferation by regulating proliferation factors in myoblasts by targeting PPP1R13B. Notably, exogenous estradiol supplementation to myoblasts regulated the expression of oar-miR-485-5p and PPP1R13B and promoted myoblast proliferation. These results provided new insights into the molecular mechanism by which ovaries influence muscle growth and development in sheep.

Skeletal muscle and adipose tissue reserves and mobilisation in transition Holstein cows: Part 1 Biological variation and affecting factors

Nutrient deficit during the periparturient period leads to mobilisation of body energy and protein reserves. Research regarding fat reserves and mobilisation is extensive, while, on the contrary, investigation of muscle mobilisation during the periparturient period is limited. The aim of this cohort study was to simultaneously investigate the biological variation of skeletal muscle and subcutaneous fat reserves together with their mobilisation in transition Holstein cows of different herds, using ultrasonography, and to assess potential affecting factors. For this purpose, ultrasound measurements of longissimus dorsi muscle thickness (LDT) and backfat thickness (BFT) from 238 multiparous cows of six dairy farms were obtained at six time points across the transition period (from 21 days pre- to 28 days postpartum). Concentrations of serum creatinine and non-esterified fatty acids were determined in order to confirm the loss of muscle mass and adipose tissue, respectively. Cases of clinical postparturient diseases and subclinical ketosis (scKET) during the first 28 days postcalving were recorded. Cows mobilised on average 32.8% and 37.3% of LDT and BFT reserves, respectively. Large between-cow variation was observed for both the onset and the degree of mobilisation. Time point, initial body condition score and parity were the most important predictors of LDT variation. Cows diagnosed with metritis (MET) had lower LDT postpartum and mobilised more muscle depth compared to cows not diagnosed with MET. Initial BCS, time point, initial BW (estimated by heart girth measurement) and parity were the most important predictors of BFT variation. Cows diagnosed with MET mobilised more backfat between -7d and 7d compared to cows not diagnosed with MET. Cows with scKET mobilised more backfat between 7- and 21 days postpartum compared to healthy ones. Variation of subcutaneous fat and skeletal muscle reserves during the transition period was large and affected by herd and several cow-level factors.

Skeletal muscle and adipose tissue reserves and mobilisation in transition Holstein cows: Part 2 association with postpartum health, reproductive performance and milk production

The aim of this study was, for the first time, to simultaneously assess the association of skeletal muscle and subcutaneous fat reserves and their mobilisation, measured by ultrasonography, with the incidence of specific postparturient health, reproduction, and milk production traits. For this purpose, ultrasound measurements of longissimus dorsi thickness (LDT) and backfat thickness (BFT) from 238 multiparous cows from 6 dairy farms were obtained at 6 time points during the transition period (from 21 days pre- to 28 days postpartum). In each case, LDT and BFT measurements at each time point and LDT and BFT mobilisation variables at each study period were assessed simultaneously. Cases of specific clinical postparturient diseases and subclinical ketosis were recorded. An additional disease trait was used, defined as the presence or absence of at least one clinical condition after calving (CD_1-28). The associated disease odds with LDT/BFT variables were assessed with binary logistic regression models. The associated hazard for 1st artificial insemination (AI) and for pregnancy by 150 days-in-milk (PREG_150DIM) was assessed with Cox proportional hazard models. Moreover, binary logistic models were used to assess the associated odds for pregnancy to 1^stAI (PREG_1^stAI). Finally, association with 30d, 100d and 305d milk yield was assessed with linear regression models. Increased muscle depth during transition was negatively associated with odds for metritis and CD_1-28, while associations with odds for subclinical ketosis were inconclusive. Moreover, increased LDT reserves were associated with greater hazard for 1st AI by 150 days-in-milk, but results were inconclusive regarding odds for PREG_1^stAI. Increased LDT mobilisation was associated with increased odds for metritis. Increased BFT reserves were positively associated with odds for metritis, CD_1-28 and subclinical ketosis and with decreased hazard for PREG_150DIM. Increased BFT mobilisation was associated with increased odds for subclinical ketosis and with decreased odds for PREG_1^stAI and decreased hazard for PREG_150DIM. Cows with moderate BFT reserves performed better. Finally, increased BFT mobilisation during -21d to -7d from parturition was associated with less milk by 30d and 100d. On the contrary, increased BFT mobilisation during -7d to 7d was associated with more milk by 305d. Metabolism of muscle and fat tissue during transition period was differently associated with different postparturient health, reproduction and milk production traits. In general, greater muscle mass and moderate fat reserves with limited muscle and fat mobilisation were associated with better performance.

Identification of differentially expressed genes at different post-natal development stages of longissimus dorsi muscle in Tianzhu white yak

The regulatory mechanisms controlling post-natal muscle development in the yak (Bos grunniens) are still largely unknown, yet the growth and development of muscle is a complex process that plays a crucial role in determining the yield and quality of an animal's meat. In this study, we performed a transcriptome analysis based on the RNA sequencing (RNA-Seq) of yak longissimus dorsi muscle tissue obtained from calves (6 months of age; 6 M), young adults (30 months of age; 30 M) and adult (54 months of age; 54 M) to identify which genes are differentially expressed and to investigate their temporal expression profiles. In total, 1788 differentially expressed genes (DEGs) (|log2FC| ≥ 1, P-adjusted < 0.05) were detected by pairwise comparisons between the different age groups. The expression levels of 10 of the DEGs were confirmed using reverse transcription-quantitative PCR (RT-qPCR), and the results were consistent with the transcriptome profile. A time-series expression profile analysis clustered the DEGs into four groups that could be divided into two classes (P < 0.05): class 1 profiles, which had up-regulated patterns of gene expression and class 2 profiles, which featured down-regulated patterns. Based on that cluster analysis, GO enrichment analysis revealed 1073, 127, and 184 terms as significantly enriched in biological process (BP), cellular component (CC), and molecular function (MF) categories in the class 1 profiles, while 714, 66, and 206 terms were significantly enriched in BP, CC, and MF in the class 2 profiles. A KEGG pathway analysis revealed that DEGs from the class 1 profiles were enriched in 62 pathways, with the most enriched being the phosphoinositide 3-kinase (PI3K) - protein kinase B (Akt)-signaling pathway. The DEGs from the class 2 profiles were enriched in 16 pathways, of which forkhead box protein O (FoxO) - signaling was the most enriched. Taken together, these results provide insight into the mechanisms of skeletal muscle development, as well suggesting some potential genes of importance for yak meat production.

Feeding a high oleic acid (C18:1) diet improves pleasing flavor attributes in pork

One of the main drivers in consumer meat choice is flavor with some pleasing flavor attributes associated with high oleic acid (C18:1) content in the intramuscular fat. This project aimed to produce pork with a distinctively pleasant bouquet by feeding C18:1 rich macadamia oil compared to corn oil. The project also tested three feed formulations based on cereals and pulses representing different pork producing areas: corn/soy (CS), sorghum-lupins (SL), or wheat/canola (WC). Compared to corn oil, feeding macadamia oil resulted in a significant increase in the C18:1 content in pork loin (longissimus dorsi) with the CS showing a higher impact than the WC diets. Pork loins from the two CS-based groups (CS-Corn and CS-Macadamia) were selected for a consumer sensory study involving 82 panelists (39 of Chinese background). Across ethnic backgrounds the taste of high C18:1 pork resulted in the highest hedonic values.

Effects of high-oxygen, carbon monoxide modified atmospheres and vacuum packaging on quality of Longissimus thoracis et lumborum steaks from Nellore cows during ageing

Nellore (Bos indicus) cows play an important role in Brazilian beef production. Here, we investigated whether modified atmosphere packaging (MAP) technology could contribute to improving the quality of Nellore cow steaks. To verify this, steaks obtained from Longissimus thoracis et lumborum (LTL) were stored at 2 °C for 28 days using different packaging systems, with one being vacuum and the others being three MAP systems: 75% O₂/25% CO₂ (75%O₂-MAP), 60% CO₂/0.2% CO/39.8% N₂ and 40% CO₂/0.4% CO/59.6% N₂ (0.2%CO-MAP and 0.4%CO-MAP, respectively). Steaks packaged using the CO-MAP showed improved color stability of fresh meat. In turn, the 75%O₂-MAP drastically affected the oxidative stability related to proteins and lipids compared to both anaerobic environments (CO-MAP and vacuum). The CO-MAP increased tenderization and ultrastructural changes when compared to the aerobic MAP without affecting pH, collagen or cooking loss, which were influenced by the storage time. In conclusion, MAP technology may improve the quality and appearance of fresh meat originating from Nellore cows, being a promising alternative for the Brazilian beef industry.

Effects of diet supplementation with rumen-protected betaine on carcass characteristics and fat deposition in growing lambs

This study evaluated the effects of dietary rumen-protected betaine (RPB) supplementation on the fat deposition of lambs. Sixty Hu sheep were randomly divided into 5 groups. The lambs were fed a control diet (CON) or diets supplemented with 1.1 g/d unprotected betaine (UPB), 1.1 g/d RPB, 2.2 g/d RPB or 3.3 g/d RPB for 70 days. Compared with UPB, the abdominal fat in 2.2 g/d RPB supplemented group was decreased (P < .05). Compared with CON and UPB, the fat contents in longissimus dorsi (LD) of RPB treatments were increased (P < .01). With increasing of RPB levels, the fat content in the LD was quadratically increased (P < .05). Compared with CON, genes expression of PI3K, mTOR and S6K1 in the LD of RPB treatments were up-regulated (P < .05). In conclusion, RPB supplementation decreased the abdominal fat in lambs but increased the fat content in lamb meat, and this effect might be regulated by mTOR signaling.

Sequencing and characterization of miRNAs and mRNAs from the longissimus dorsi of Xinjiang brown cattle and Kazakh cattle

Breed improvement is an important genetic process affecting meat quality. Compared with Kazakh cattle, Xinjiang brown cattle have significantly improved carcass quality and meat quality. To elucidate the molecular mechanisms underlying the improvements in Xinjiang brown cattle and the differences in beef quality between the two breeds, we used RNA-Seq to study differentially expressed genes and miRNAs and regulatory pathways related to adipogenesis, myogenesis and fibrogenesis in the longissimus dorsi muscles of Xinjiang brown cattle and Kazakh cattle. The results showed that 1669 genes were differentially expressed in the longissimus dorsi muscle tissues of Xinjiang brown cattle and Kazakh cattle; 879 genes were upregulated and 790 genes were downregulated in Xinjiang brown cattle compared to Kazakh cattle. These genes were mainly involved in PPAR signaling, unsaturated fatty acid biosynthesis and vascular smooth muscle contraction. Additionally, 346 differentially expressed miRNAs were identified, of which 265 miRNAs were downregulated and 81 miRNAs were upregulated in Xinjiang brown cattle compared to Kazakh cattle. Association analysis of the differentially expressed genes and miRNAs revealed that 86 differentially expressed miRNAs related to adipogenesis were associated with 31 differentially expressed genes, 76 differentially expressed miRNAs associated with myogenesis were associated with 28 differentially expressed genes, and 54 differentially expressed miRNAs associated with fibrogenesis were associated with 19 differentially expressed genes. miRNA-target gene networks were also constructed. Finally, the expression levels of 19 genes and miRNAs were verified by qRT-PCR. Some differentially expressed genes, including FABP4, ACTA2 and ACTG2, were shown to play an important role in beef meat quality. This is the first study to perform transcriptomic analysis of muscle tissues from Xinjiang brown and Kazakh cattle.

Deciphering the miRNA transcriptome of Rongchang pig longissimus dorsi at weaning and slaughter time points

MicroRNA (miRNA) is essential for the process of gene posttranscriptional regulation in skeletal muscle of many species, such as mice, cattle and so on. However, a little number of miRNAs have been reported in the muscle development of Chinese native pig breeds. In this study, the longissimus dorsi transcripts of Chinese native Rongchang pig at weaning and slaughter time points were analysed for miRNA-seq. The results showed that 19 novel and 186 known miRNAs involved in the Rongchang pig skeletal muscle development were identified. Based on these findings, we further confirmed that porcine miR-127, miR-299 and miR-432-5p were obviously down-expressed in adult pig (287 days of age), while miR-7134-3p and 664-5p were significantly up-expressed in weaning pig (35 days of age). In other words, these miRNAs could be the potential molecular markers and play vital roles in the muscle development process. Moreover, we found miR-127 could inhibit the proliferation and myogenesis of porcine satellite cells in longissimus dorsi muscle. Our findings will provide deep insight into miRNA function for pork quality research with Chinese indigenous pig breeds.

Evidence of marbling as a single connected entity in beef striploins

Serial sections of Angus striploins that varied in marbling were analysed in three dimensions to assess potential differences in intramuscular fat structure. The majority of the intramuscular fat appeared to be connected along the 100 mm of muscle in both the highly marbled and less marbled striploins. Thus, rather than having dispersed individual flecks of marbling, the intramuscular fat was a single entity within the striploin. The local shape patterns of this entity varied with marbling level in that the structure had an increased diameter in the highly marbled striploins. However, the amount of branching in the intramuscular fat did not vary with the level of marbling. The results suggest that marbling may occur along an internal structure, such as the vascular system or interstitium, in the longissimus muscle. It is postulated that when beef marbling increases, additional intramuscular fat is not deposited in isolated sites but along this internal structure, widening the existing entity rather than changing the shape.

An investigation on the relationship among marbling features, physiological age and Warner-Bratzler Shear force of steer longissimus dorsi muscle

Researchers nowadays have paid much attention to the relationships between tenderness and marbling, or physiological age. While the marbling was mainly evaluated qualitatively with scores or grades, and rarely related with physiological age. Present study was carried out to analyze the marbling features of longissimus dorsi muscle between the 12th and 13th ribs from 18, 36, 54 and 72 months old Simmental steers were quantitatively described with area and perimeter using computer vision technique. Relationship between Warner-Bratzler Shear force (WBSF), physiological age and the marbling features were examined performing regression analysis. The results revealed that WBSF positively correlated with physiological age, but negatively with marbling area and perimeter. Regression analysis showed that the relationship between the shear force and the steers' age was more close to the quadratic curve (R² = 0.996) and exponential curve (R² = 0.957). It was observed during study that marbling grew with steers age. Marbling features were in linear correlation with the steers' age, with R² = 0.927 for marbling area and R² = 0.935 for marbling perimeter. The industries in future may speculate beef tenderness and physiological age based on the marbling features (area and perimeter), which can be determined through the online image acquisition system and image processing.

Effects of age on slaughter performance and meat quality of Binlangjang male buffalo

Twelve representative buffalo were selected from 22 suckling calves, 41 weaned calves, 57 reserve bulls and 20 adult bulls for slaughter. The study aims to assess the effect of age on dressing percentage, meat percentage and carcass meat yield and physico-chemical properties of longissimus dorsi and biceps femoris, and to evaluate the correlation between live weight and marbling, backfat thickness, rib eye area. The results showed that the slaughter performance and meat quality of Binlangjang male buffalo showed an obvious change with age. The dressing percentage decreased from 54.93% to 51.22% with the increase of age, while meat percentage and carcass meat yield increased gradually with age, which were 34.58–38.59%, 62.95–75.34%; Marbling, backfat thickness and rib eye area increased with age, and there was significant difference between the situation before 3 months and after 12 months of age (P < 0.05). The moisture content was maximum at birth, which then gradually decreased, but the difference was insignificant (P > 0.05). The levels of fat, protein, cholesterol and inosine acid were significantly different before 3 months of age from those after 12 months (P < 0.05). Cholesterol content was negatively correlated with age, the minimum was 80.25 mg/100 g; Inosine acid content increased with age, reaching 133.11 mg/100 g. Marbling, backfat thickness, rib eye area had a high correlation with live weight, with correlation coefficients respectively at 0.9096, 0.9291, 0.9551. Based on the prediction model of live weight, Buffaloes was suitable for slaughtering for superior slaughter performance and meat quality after 24 months of age.

Omics integrating physical techniques: aged Piedmontese meat analysis

Piedmontese meat tenderness becomes higher by extending the ageing period after slaughter up to 44 days. Classical physical analysis only partially explain this evidence, so in order to discover the reason of the potential beneficial effects of prolonged ageing, we performed omic analysis in the Longissimus thoracis muscle by examining main biochemical changes through mass spectrometry-based metabolomics and proteomics. We observed a progressive decline in myofibrillar structural integrity (underpinning meat tenderness) and impaired energy metabolism. Markers of autophagic responses (e.g. serine and glutathione metabolism) and nitrogen metabolism (urea cycle intermediates) accumulated until the end of the assayed period. Key metabolites such as glutamate, a mediator of the appreciated umami taste of the meat, were found to constantly accumulate until day 44. Finally, statistical analyses revealed that glutamate, serine and arginine could serve as good predictors of ultimate meat quality parameters, even though further studies are mandatory.

Effect of Dietary Supplementation of Blood Meal and Additional Magnesium on Carnosine and Anserine Concentrations of Pig Muscles

The objective of this study was to investigate the effect of dietary supplementation of blood meal as a source of L-histidine, and the addition of magnesium (Mg) as a catalyst of carnosine synthetase for the carnosine and anserine concentrations of pig muscles (longissimus dorsi, LD and vastus intermedius, VI). A total of twenty-four pigs with an average body weight of 60.2±4.2 kg were randomly allotted to one of three dietary treatments (eight replicates), during 56 d of the feeding trial. Dietary treatments included: (1) Basal: basal diet; (2) BM: 95% basal diet + 5% blood meal; and (3) BM+Mg: 94.8% basal diet + 5% blood meal + 0.2% MgO (60% Mg). Results indicated that drip loss in the LD was less (p<0.05) for meat with BM+Mg treatment than that with Basal treatment, but the values for BM treatment did not differ from those of the other two treatment groups. The concentrations of carnosine in the LD were increased by 10.0% in both BM and BM+Mg treatment groups over the Basal treatment group (significance not verified). The concentrations of carnosine and anserine in the VI were not affected by the dietary treatments. Inclusion of additional Mg in diets had no effect on carnosine and anserine concentrations in the LD and VI. In conclusion, dietary supplementation of blood meal could be a potential method of fortifying the pork with carnosine. Inclusion of additional Mg in the diets containing blood meal had no benefit on carnosine and anserine depositions in pig muscles.

Fatty acid composition differences between adipose depot sites in dairy and beef steer breeds

The objective of the study was to compare fatty acid composition of longissimus dorsi (LD) and kidney fat (KF) in Holstein steers (HS), Simmental steers (SS) and Chinese LongDong Yellow Cattle steers (CLD). All steers received the same nutrition and management but in different locations. Cattle were harvested at approximately 550 kg and fatty acid composition of longissimus dorsi and kidney fat was analyzed in samples taken after 3 days of aging. There was evidence (P < 0.05) that C18:3n6 was greater in KF than LD in CLD cattle but not in HS or SS cattle. Percentage C18:1n9, C18:2n6, C18:3n3, and n6 fatty acids were greater in LD than KF for all breeds (P < 0.05), but the difference between fat sources for n6 in CLD cattle was smaller than the other two breeds. The LD had greater percentage of polyunsaturated fatty acids (PUFA), monounsaturated fatty acids (MUFA), and a greater ratio of n6:n3 PUFAs compared to the KF in each breed (P < 0.05). The △(9)-desaturase catalytic activity index was greater in LD than in KF in each breed group (P < 0.05). Percentage cis-9, trans-11 CLA was greater in KF than LD in HS (P < 0.05) but not SS or CLD cattle. These results indicate fatty acid percentages generally differed between longissimus dorsi fat and kidney fat. Further, there was some indication that some of these differences between fatty acid deposition sites were not consistent across breed group.

Fatty acid and transcriptome profiling of longissimus dorsi muscles between pig breeds differing in meat quality

Fat and lean pig breeds show obvious differences in meat quality characteristics including the fatty acid composition of muscle. However, the molecular mechanism underlying these phenotypes differences remains unknown. This study compared meat quality traits between Lantang (a Chinese indigenous breed) and Landrace (a typical lean breed). The Lantang pigs showed higher L* values and intramuscular fat content, lower pH_45min, pH_24h and shear force in longissimus dorsi (LD) muscle than Landrace (P < 0.05). Fatty acid analysis demonstrated the lower monounsaturated fatty acids (MUFA) and higher polyunsaturated fatty acids (PUFA) percentage in Lantang LD than that in Landrace LD (P < 0.05). To further identify candidate genes for fatty acid composition, the transcriptome of LD muscle from the two breeds were measured by microarrays. There were 586 transcripts differentially expressed, of which 267 transcripts were highly expressed in Lantang pigs. After the validation by real-time quantitative PCR, 13 genes were determined as candidate genes for fatty acid composition of muscle, including Stearoyl-CoA desaturase (SCD). Then, a SCD over-expression plasmid was transfected into C2C12 cells to reveal the effect of SCD on the fatty acid composition in vitro. The results showed that SCD over-expression significantly increased PUFA proportion, while reduced that of saturated fatty acids (SFA) in C2C12 cells (P < 0.05). In summary, this study compared the differences of fatty acid composition and transcriptome in two breeds differing in meat quality, and further identified the novel role of SCD in the regulation of PUFA deposition.