Intramuscular Fat Content Research Articles

Single-cell transcriptome reveals three types of adipocytes associated with intramuscular fat content in pigs.

Intramuscular fat is an essential component of muscle tissue, and understanding its contribution to skeletal muscle fat infiltration and meat quality, together with the underlying genetic mechanisms, is a major topic in pig husbandry. However, the composition of cell types and gene expression profiles essential for this purpose remain largely unexplored. Here, we performed single-cell transcriptome analysis on muscle tissue from adult pigs and identified 15 cell types, including three previously uncharacterized types of adipocytes: Adipocyte 1, Adipocyte 2, and Aregs. Phenotypic analysis showed their proportions correlated closely with intramuscular fat content. Based on integrated analysis of ATAC-seq with RNA-seq data, Adipocyte 1 and Aregs have gene expression profiles and transcription factor (TF) motif enrichment typical of adipocytes. On the other hand, myogenic TF motifs were enriched in marker gene promoters in Adipocyte 2, suggesting that these cells originate from muscle cells. Moreover, the marker gene promoters and lineage-specific TF expression in these three adipocyte types were conserved between pigs and humans. These findings provide deep insights towards understanding the complexity of mammalian intramuscular adipocyte types and the gene regulation underlying their organization and function.

Effect of by-products-based diet and intramuscular fat content on volatile compounds from pork.

This study evaluated the effects of a fibre- and fat-rich by-products-based diet and the intramuscular fat (IMF) content on volatile compounds in pork. Meat samples were collected from sixteen gilts included in a feeding trial. Half of the animals were fed a conventional diet based on wheat, maize, barley and soybean meal, whereas the other half were fed a by-products-based diet that contained corn germ meal, malt sprouts, crispbread meal and proticorn, but no cereals or soya. Within each dietary treatment, four meat samples were selected from pigs in the upper quartile of IMF content (average 2.40%±0.18%, n=8) and four from the lower quartile of IMF content (average 1.45%±0.10%, n=8). SPME-GC-MS was used to evaluate the volatile profile of pork. A total of 45 volatile compounds were identified in the cooked pork samples. Aldehydes were the predominant chemical class in terms of the number of identified volatile compounds. No diet × IMF interaction was observed for the abundance of volatile compounds. Dietary treatment and IMF content significantly influenced the abundance of one and two aldehydes, respectively. Hexanal was more abundant in the meat of animals fed the conventional diet compared to the diet based on by-products. Tridecanal and tetradecanal were less abundant in pork with higher IMF levels. As precursors of volatile compounds, fatty acids were also analysed in the raw meat samples by GC. The concentrations of most fatty acids were higher in pork with higher IMF content but were not affected by diet. In conclusion, the volatile compounds profile of pork was only marginally affected by IMF content and feeding a by-products-based diet in the present study.

Genetic Polymorphisms in HMGCS1 Gene and Its Association with Slaughter Characteristics, Meat Quality, and Organ Coefficients in Guizhou White Goats.

This study aimed to identify polymorphisms in the gene encoding the 3-hydroxy-3-methylglutaryl-CoA synthase 1, HMGCS1, and analyze their association with slaughter characteristics, meat quality, and organ coefficients in Guizhou white goats. A total of 153 twelve-month-old Guizhou white goats (78 male and 75 female) were included in the study. Slaughter characteristics, meat quality, and organ coefficients were assessed. Association analyses between genotypes and phenotypic traits were conducted using a generalized linear model. Four polymorphic loci were identified, i.e., g.15523T>C, g.15530G>C, g.18413T>C, g.19711G>A in exons 5, 8, and 9 of the HMGCS1 gene. Across all polymorphic loci, males of the same genotype generally exhibited significantly better slaughter traits compared to females of the same genotype (p < 0.05). At the g.18413T>C locus, differences in shear force were observed between males and females of the same genotype and within the same sex across different genotypes (p < 0.05). Organ coefficients were significantly higher in males of the same genotype compared to females (p < 0.05). The g.15523T>C and g.15530G>C loci were found in strong linkage disequilibrium and significantly associated with intramuscular fat content (p < 0.05). Fat content in diploid Hap2/2 individuals was significantly higher than in Hap1/1 and Hap1/2 (p < 0.05). At the g.19711G>A locus, female goats with the CC genotype showed significantly higher levels of dry matter compared to male goats of the same genotype and female goats of other genotypes within the group. Organ coefficients for the liver and hooves in male goats were significantly higher than in females of the same genotype (p < 0.05). The strongly linked loci g.15523T>C and g.15530G>C were significantly associated with intramuscular fat content and could be used as molecular markers for enhancing this trait in goat breeding programs, fostering the development of goat production.

Performance, Carcass Traits and Meat Quality of Lambs Fed with Increasing Levels of High-Oleic Sunflower Cake

The aim of this study was to evaluate the effect of sunflower cake from high-oleic seeds on performance, carcass characteristics, meat quality, and intramuscular fatty acid composition of finishing lambs. Thirty-six crossbred ewe lambs were assigned to four treatments (nine lambs/treatment) in a completely randomized design: 0 (control), 150, 300 and 450 g/kg DM of high-oleic sunflower cake. The lambs were weighed weekly and slaughtered with 42.3 ± 0.18 kg body weight and 270 ± 10.8 days of old. The inclusion of sunflower cake did not affect weight gain, dry matter intake and metabolizable energy intake (p &gt; 0.05). There was an increase in neutral detergent fiber and EE intake (p &lt; 0.01) with the inclusion of sunflower cake in the diet of the lambs. The inclusion of sunflower cake reduced hot and cold carcass yields (p &lt; 0.01). Intramuscular fat content, L*, oleic acid, rumenic acid and EPA fatty acids linearly increased (p &lt; 0.01) with the inclusion of high-oleic sunflower cake. The inclusion of high-oleic sunflower cake reduced saturated fatty acids (p &lt; 0.01), except stearic acid, which linearly increased (p &lt; 0.01). Up to 450 g/kg DM of high-oleic sunflower cake in the diet of lambs did not affect animal performance while providing a higher deposition of fat with better fatty acid composition for human consumption.

Bta-miR-484 Inhibits Bovine Intramuscular Adipogenesis by Regulating Mitotic Clonal Expansion via the MAP3K9/JNK/CCND1 Axis.

Intramuscular fat (IMF) content is a critical indicator of the beef nutritional value and flavor. In this study, we focused on bta-miR-484, a microRNA that is differentially expressed during the adipogenic differentiation of bovine intramuscular adipocytes and is negatively correlated with the IMF content across different cattle breeds. Our findings demonstrate that bta-miR-484 inhibits adipogenic differentiation without altering the fatty acid composition of bovine intramuscular adipocytes. miRNA pull-down and dual-luciferase reporter assays confirmed that MAP3K9 is a target gene of bta-miR-484. Furthermore, bta-miR-484 suppresses the JNK signaling pathway by targeting MAP3K9, leading to decreased CCND1 expression, which impedes the mitotic clonal expansion (MCE) process and inhibits intramuscular adipocyte differentiation. In summary, this study uncovers a novel mechanism by which bta-miR-484 regulates bovine IMF content and provides the first exploration of MCE during intramuscular adipocyte adipogenic differentiation. These findings offer valuable theoretical insights into beef cattle breeding and molecular improvements.

Fermented Cassava Residue Meal Improves Meat Quality by Regulating Muscle Fiber and Enhancing Lipid Metabolism in Huanjiang Mini-Pigs.

This research investigated the effects of cassava residue meal (CRM) and fermented CRM (FCRM) on the growth performance, serum lipid indicators, carcass traits, and meat quality of Huanjiang mini-pigs. One hundred twenty Huanjiang mini-pigs with similar BW (body weight, 8.85 ± 0.64 kg) were divided into three dietary treatment groups: the CON group with a basal diet; the CRM group with a diet containing 5% CRM; and the FCRM group with a diet containing 5% FCRM. The feeding trial was conducted for 30 days. The findings revealed that dietary CRM and FCRM did not influence the growth performance and diarrhea rate of Huanjiang mini-pigs (p > 0.05). Dietary FCRM supplementation increased serum total cholesterol level compared to the CON group while decreasing serum cholinesterase level compared to the CON and CRM groups (p < 0.05). The level of serum low-density lipoprotein-cholesterol was higher (p < 0.05) in the CRM and FCRM groups in regard to the CON group. In addition, CRM and FCRM supplementation reduced (p < 0.05) the backfat thickness and carcass yield of Huanjiang mini-pigs. The meat quality analysis showed that dietary CRM and FCRM improved the meat quality by increasing the intramuscular fat content and redness (a*) value and decreasing the lightness (L*) value. Moreover, the MyHC-IIx expression in the longissimus thoracis (LT) muscle was upregulated (p < 0.05) in the CRM group, while MYHC-IIb expression displayed an increasing trend (p = 0.076) in the FCRM group relative to the CON group. The fatty acid composition in the LT muscle also revealed that the C20:0 level was lower in the CRM and FCRM groups, while the ∑SFA and ∑SFA/∑UFA were reduced (p < 0.05) in the FCRM group relative to the CON group. In summary, dietary CRM and FCRM supplementation improved the meat quality of Huanjiang mini-pigs without affecting growth performance and diarrhea rate. Notably, FCRM exhibited better effects on meat quality than CRM.

Impact of dietary lysophospholipids supplementation on growth performance, meat quality, and lipid metabolism in finishing bulls fed diets varying in fatty acid saturation

BackgroundThe objective of this study was to evaluate the effects of dietary fatty acids (FA) saturation and lysophospholipids supplementation on growth, meat quality, oxidative stability, FA profiles, and lipid metabolism of finishing beef bulls. Thirty-two Angus bulls (initial body weight: 623 ± 22.6 kg; 21 ± 0.5 months of age) were used. The experiment was a completely randomized block design with a 2 × 2 factorial arrangement of treatments: 2 diets with FA of different degree of unsaturation [high saturated FA diet (HSFA) vs. high unsaturated FA diet (HUFA)] combined with (0.075%, dry matter basis) and without lysophospholipids supplementation. The bulls were fed a high-concentrate diet (forage to concentrate, 15:85) for 104 d including a 14-d adaptation period and a 90-d data and sample collection period.ResultsNo interactions were observed between dietary FA and lysophospholipids supplementation for growth and meat quality parameters. A greater dietary ratio of unsaturated FA (UFA) to saturated FA (SFA) from 1:2 to 1:1 led to lower DM intake and backfat thickness, but did not affect growth performance and other carcass traits. Compared with HSFA, bulls fed HUFA had greater shear force in Longissimus thoracis (LT) muscle, but had lower intramuscular fat (IMF) content and SOD content in LT muscle. Compared with HUFA, feeding the HSFA diet up-regulated expression of ACC, FAS, PPARγ, and SCD1, but down-regulated expression of CPT1B. Compared with feeding HSFA, the HUFA diet led to greater concentrations of c9-C18:1 and other monounsaturated FA in LT muscle. Feeding HUFA also led to lower plasma concentrations of cholesterol, but there were no interactions between FA and lysophospholipids detected. Feeding lysophospholipids improved growth and feed conversion ratio and altered meat quality by increasing muscle pH24h, redness values (24 h), IMF content, and concentrations of C18:3, C20:5 and total polyunsaturated fatty acids. Furthermore, lysophospholipids supplementation led to lower malondialdehyde content and up-regulated the expression of ACC, FAS, and LPL in LT muscle.ConclusionsResults indicated that supplementing a high-concentrate diet with lysophospholipids to beef bulls can enhance growth rate, feed efficiency, meat quality, and beneficial FA. Increasing the dietary ratio of UFA to SFA reduced DM intake and backfat thickness without compromising growth, suggesting potential improvements in feed efficiency.

Identification of key genes affecting intramuscular fat deposition in pigs using machine learning models.

Intramuscular fat (IMF) is an important indicator for evaluating meat quality. Transcriptome sequencing (RNA-seq) is widely used for the study of IMF deposition. Machine learning (ML) is a new big data fitting method that can effectively fit complex data, accurately identify samples and genes, and it plays an important role in omics research. Therefore, this study aimed to analyze RNA-seq data by ML method to identify differentially expressed genes (DEGs) affecting IMF deposition in pigs. In this study, a total of 74 RNA-seq data from muscle tissue samples were used. A total of 155 DEGs were identified using a limma package between the two groups. 100 and 11 significant genes were identified by support vector machine recursive feature elimination (SVM-RFE) and random forest (RF) models, respectively. A total of six intersecting genes were in both models. KEGG pathway enrichment analysis of the intersecting genes revealed that these genes were enriched in pathways associated with lipid deposition. These pathways include α-linolenic acid metabolism, linoleic acid metabolism, ether lipid metabolism, arachidonic acid metabolism, and glycerophospholipid metabolism. Four key genes affecting intramuscular fat deposition, PLA2G6, MPV17, NUDT2, and ND4L, were identified based on significant pathways. The results of this study are important for the elucidation of the molecular regulatory mechanism of intramuscular fat deposition and the effective improvement of IMF content in pigs.

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.

Transcriptomic and metabolomic-based revelation of the effect of fresh corn extract on meat quality of Jingyuan chicken.

To investigate the effect of fresh corn extract (FCE) on chicken meat quality, 135-day-old Jingyuan chicken hens were fed diets containing different doses of FCE (CON, 0.3% FCE, 0.6% FCE and 0.9% FCE) until 180 day-old in this study. Meat performance measurements showed that the 0.6% FCE group of Jingyuan chickens had higher intramuscular fat (IMF), pressing loss (PL), amino acid and fatty acid contents (P < 0.05). Their breasts were collected for transcriptomic and metabolomic analyses (n=8), and 210 Differentially expressed genes (DEGs) and 29 Differentially expressed genes (DEMs) were obtained. Gene Ontology (GO) analyses of DEGs indicate multiple entries involved in IMF synthesis such as skeletal system development and cellular response to amino acid stimulation. Kyoto Encyclopedia of Genes and Genomes (GSEA-KEGG) analysis identified sphingolipid_metabolism and multiple genes affecting IMF deposition including SPHK1, CERS1, CERS6, GLB1L, SGMS2, UGT8, and UGCG. KEGG and metabolite correlation analyses of DEMs identified Aspartate, PI 38:5; PI(18:1/20:4), PI 36:3; PI(18:1/18:2), PI 36:2; PI(18:0/18:2), and PI 34:1; PI(16:0/18:1) as the likely major influences on IMF deposition in the DEMs. Correlation analysis revealed that shear force (SF) was significantly and positively correlated with Aspartate and CERS6; PL was significantly and positively correlated with SPHK1 and UGCG (P < 0.05). IMF was significantly and positively correlated with PI 34:1; PI (16:0/18:1), SPHK1 and UGCG; and flesh colour yellowness b* was significantly and positively correlated with SGMS2 (P < 0.05). The above results indicate that feeding a basal diet containing 0.6% FCE can improve the meat quality of Jingyuan chicken, which provides a theoretical basis for improving the meat quality of Jingyuan chicken.

Effect of hay type and breed on the fattening, centesimal and fatty acid composition of Nigerian sheep.

This study aimed to evaluate the intake, performance, quality, and fatty acids (FA) composition of the meat of three Nigerian sheep breeds (Balami, Uda, and Yankasa) fed two different hays, Brachiaria decumbens or Digitaria smutsii. A total of sixty sheep, twenty from each breed, Balami, Uda, and Yankasa, were used, with average body weights of 24.7 ± 3.5kg, 25.5 ± 3.6kg, and 25.5 ± 3.5kg, respectively. The sheep were arranged in a factorial 2 (hay types) × 3 (breeds) design within a completely randomized setup, totalling ten experimental units per treatment. There was no significant (p > 0.05) interaction effect between breed and hay type on any variables. Sheep-fed D. smutsii hay presented higher (p ≤ 0.05) DM intake from the concentrate, hay, total feed, final BW, ADG, intramuscular fat, and FA contents than sheep-fed B. decumbens, except for 18:1n-9, where sheep fed B. decumbens presented higher (p ≤ 0.05) concentration. Balami sheep presented higher (p ≤ 0.05) total weight gain than the Uda breed and once performed better than the Yankasa breed, without difference (p > 0.05) to feed efficiency. Longissimus lumborum of the Yankasa breed presented lower concentrations (p ≤ 0.05) of total polyunsaturated FA (PUFA) than Balami and Uda sheep. The content of n-3 and n-6 PUFA (linolenic, EPA, DPA, and DHA), n-6/n-3 ratio, and EPA + DHA were higher in the Balami sheep than in the Uda sheep. Balami breed had the highest carcass weight and meat protein content but had a lower (p ≤ 0.05) moisture content than other breeds. Uda and Yankasa sheep presented similar moisture content (p ≤ 0.05). However, the carcass weight, protein, and fat content of the longissimus lumborum were higher (p ≤ 0.05) in Uda compared to Yankasa sheep. Nigerian sheep fed D. smutsii hay compared to B. decumbens hay to provide greater DM intake, improving fattening and meat fat and increasing all fatty acids in the longissimus lumborum. Balami breed presented greater DM intake, performance, and carcass weight, and consequently higher intramuscular fat deposition and concentration of most fatty acids in the longissimus lumborum than the breeds Uda and Yankasa.

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.

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 21days, gave significantly better eating quality than 7days 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.

Residual Feed Intake in Hereford Steers: Is It Associated with Carcass and Meat Quality Characteristics?

Carcass and meat quality traits were evaluated on 136 Hereford steers categorized according to their residual feed intake (RFI): high RFI (HRFI), medium RFI (MRFI), and low RFI (LRFI). Steers from the 3 groups of RFI did not differ (P &amp;gt; 0.05) on final live weight, hot carcass weight, carcass yield, marbling scores, ribeye area, and subcutaneous fat thickness. No differences (P &amp;gt; 0.05) were observed in the weights of tenderloin, strip loin, bottom round, knuckle, and tri-tip among RFI groups; however, steers from LRFI and MRFI had heavier (P &amp;lt; 0.05) top sirloins than HRFI animals and inside rounds from more efficient animals (LRFI) were heavier (P &amp;lt; 0.05) than HRFI steers. Steers from HRFI showed a greater (P &amp;lt; 0.05) proportion of intramuscular fat (IMF) than LRFI animals. Longissimus muscles from HRFI steers presented greater (P &amp;lt; 0.05) concentrations of saturated (SFA), monounsaturated, and polyunsaturated fatty acids (PUFA) than those from MRFI and LRFI animals. The PUFA/SFA ratio of IMF did not differ (P &amp;gt; 0.05) between LRFI and HRFI steers and neither between LRFI and MRFI. In addition, the omega 6:omega 3 fatty acids ratio did not differ (P &amp;gt; 0.05) among the 3 RFI groups. Consumer's panel acceptability scores for tenderness, flavor, and overall liking were not significantly different (P &amp;gt; 0.05) among meat samples from LRFI, MRFI, and HRFI steers. Our findings indicated that RFI would not be associated with carcass traits and meat quality of Hereford steers, except for the IMF content and fatty acids concentrations. Therefore, end-product quality would be only marginally affected when RFI characteristic is included in a Hereford breeding program.

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.

Alternative polyadenylation landscape of longissimus dorsi muscle with high and low intramuscular fat content in cattle.

Intramuscular fat content is one of the most important factors affecting beef quality. However, the role of alternative polyadenylation (APA) in intramuscular fat deposition remains unclear. We compared APA events in muscle samples from high and low intramuscular fat (IMF) cattle, based on RNA-seq data. A total of 363 significant APAs were identified. Notably, the number of shortened 3'UTR events exceeded the number of lengthened 3'UTR events, and genes associated with shortened 3'UTR events were enriched in fatty acid metabolism-related pathways. Most APA events had alternative 3'UTR (aUTR) lengths of 200 to 300bp. As the 3'UTR lengthened, the aUTR also lengthened (R2 = 0.79). These findings indicate that genes with longer 3'UTRs are more likely to be regulated by APA in the muscle of cattle with high IMF. To determine whether the identified APA events drove alterations in the expression of fat deposition-related genes, we analyzed the relationship between APA events and differentially expressed genes and identified several genes critical for fat deposition (e.g., PFKL and SLC1A5). Since miRNAs usually bind to the 3'UTR region of protein-coding genes and affect gene expression, we constructed an miRNA-APA network to detect several key miRNAs that may regulate fat deposition. We identified 10 important miRNAs that affect changes in IMF content, which may be gained (gained miRNA-binding sites) or lost (lost miRNA-binding sites) owing to 187 differential APA events. Our study characterized the APA profiles of cattle with high and low intramuscular fat content and provided further insights into the relationship between APA, miRNA, and fat deposition.

Nutritional Processing Quality of Sika Deer (Cervus nippon) Venison in Different Muscles.

In order to investigate the nutritional processing quality of sika deer (Cervus nippon) venison at different sites, the pH24 h, tenderness, pressurized water loss rate, meat color, intramuscular fat, moisture, protein, amino acid, fatty acid and squalene contents of sika deer venison were determined in twelve sites: foreleg, hind leg, outer tenderloin, rump, neck meat, chest meat, deer flank, abdominal rib, high rib, tenderloin, anterior tendon and posterior tendon. The results showed that the pH24 h of sika deer venison at different sites was 5.49~5.78; the tenderness of outer tenderloin (31.71 N) was the lowest, and the neck meat (68.53 N) was the highest; the squeezing moisture of tenderloin (28.12%) was the largest, and the foreleg (12.34%) was the smallest; the brightness of outer tenderloin L* (29.68) was the lowest, and the redness a* and yellowness b* of deer flank were the highest; the intramuscular fat and moisture were 0.66~4.97% and 71.00~73.78%, respectively; and the protein content of outer tenderloin (23.44%) and rump (24.02%) was high. The venison meat contained 17 kinds of amino acids, and the total amount was 63.87~79.33 g/100 g. It was rich in essential amino acids, mainly lysine and leucine, accounting for 64.29~65.39% of non-essential amino acids, which was close to the ideal protein composition. Palmitoleic acid and oleic acid were the main monounsaturated fatty acids in venison, and the contents of abdominal ribs were the highest, 16,875.33 mg/kg and 31,772.73 mg/kg, respectively. The contents of essential fatty acids were also the highest in abdominal ribs (11,225.37 mg/kg); forelegs, hind legs, outer tenderloins, rumps, neck meat, chest meat, high rib, tenderloins, anterior tendons and posterior tendons were all good sources of polyunsaturated fatty acids. Squalene content was highest in the abdominal rib (100.85 mg/kg). The nutritional processing quality of sika deer venison in different muscles is significantly different, and this study can provide a data basis for the evaluation and processing of sika deer venison quality.

Effects of partial replacement of soybean meal with hemp seed (Cannabis sativa L.) cake on the growth and meat quality in female three-yellow chickens

Hemp seed cake (HSC) (Cannabis sativa L.) is a high-quality plant-derived protein source rich in polyunsaturated fatty acid (PUFA). To assess the effects of HSC addition in diets on the growth and meat quality in broiler chicken, a total of 240 female three-yellow chickens (50 days of age) were randomly assigned to four groups and fed with varying levels of HSC (0% (HSC0), 5% (HSC5), 10% (HSC10), and 20% (HSC20)) for 9 weeks. As a result, the daily feed intake, weight gain and feed conversion efficiency were significantly increased in the HSC20 group. Moreover, the meat quality traits, including the meat colour, water-holding capacity, intramuscular fat content, and proportion of n-3 PUFA significantly improved, and the expression of lipid synthesis genes, were increased in the HSC20 group. Meanwhile, the development of immune organs and the anti-inflammatory capabilities were enhanced in the HSC20 group. In addition, the blood lipid of chicken was reduced by improving the lipid metabolism in the HSC20 group. Therefore, adding 20% HSC in the feed had a notable effect on the growth, antioxidant and immune capabilities, blood lipid metabolism, and meat performance of the female three-yellow chickens. These findings provide significant information for improving the production performance of broiler chickens through the effective utilization of HSC.

Characterization of methanolysis products from plasmalogenic lipids in horse muscle tissue

Muscle tissue is known to contain plasmalogenic lipids. Traditional methodologies for the analysis of lipids in muscle consists of methanolysis followed by gas chromatography (GC). The resultant dimethylacetals (DMA) are difficult to resolve because of extensive overlap with fatty acid methyl esters. In this study a new two-step procedure was applied to isolate DMAs from FAMEs from methanolysed horse muscle lipids (n=48) after saponification and solvent partitioning. Both total and isolated DMAs were analysed by GC and the extent of overlap was evident. The total methylated mixture was also analyzed using GC with online reduction (GC-OR x GC) which confirmed the identity of the FAME, DMA and aldehyde products. The DMA content in horse muscle tissue was found to be 55.7 mg DMAs in 100 g of meat, or 3.10 % of total lipids. The saturates 16:0 and 18:0 were the predominant DMA isomers, and 18:3n-3 and 18:2n-6 DMA were identified in this tissue. Samples with a higher (> 3 g/100 g of meat) intramuscular fat (IM) content showed a lower (p ≤ 0.05) absolute content of the DMAs compared to samples with lower IM fat content (15.3 vs 29.3 mg/g of fat, respectively).