Pork Quality Research Articles

Transcriptomic profiling of backfat and muscle in Lijiang pigs with divergent body size across growth stages.

Backfat thickness is an important economic trait that affects pork quality and flavor. The Lijiang pig (LJP), a local breed in Yunnan province, China, exhibits variations in growth and body composition. However, the molecular basis for these variations is unclear. This study aimed to analyze transcriptome profiles of backfat at different growth stages in LJP with discrepant body size: two months (M2), four months, and six months. Firstly, we analyzed the gene expression differences and discovered a significantly highest number of differentially expressed genes (DEGs) at the M2 stage. Secondly, we identified four gene profiles with reverse expression trends in LJP populations with different body sizes, and the related genes mainly associated with immune response functionality. Thirdly, we observed a lower correlation in LJP with large body size at the M2 stage, with a specific enrichment of DEGs with high genetic differentiation related to neural activity. Finally, we correlated transcriptome profiles of muscle and backfat and discovered the lowest correlation at the M2 stage. Highly correlated genes exhibited more significant differences and were prominently enriched for immune response processes. This study unveils candidate genes linked to backfat growth in LJP, emphasizing the specificity of the early growth stage of backfat.

Longissimus from Berkshire pigs in a small-scale supply chain have increased oxidative metabolism, tenderness and water-holding capacity, compared with Large White × Landrace pigs in a modern commercial supply chain

Context Selection for leanness in the modern Australian pig has resulted in inconsistent quality, including a lack of pork tenderisation during ageing. Inconsistent quality is potentially a result of differences in supply chain and breed as well as the variation in muscle fibre-type proportion in pork longissimus. Aim The aim was to investigate differences in fibre-type proportion and pork quality between Large White-Landrace pigs in a large supply chain and Berkshire pigs processed in a small supply chain. Methods Pigs (n = 22) from two suppliers with different breeds (Supplier 1, Large White × Landrace, SC1-LWLR, n = 12, modern commercial pigs; Supplier 2, Berkshire, SC2-Berk, n = 10, heritage pigs) were slaughtered and samples from the longissimus were extracted at 3, 24, and 48 h postmortem for enzyme and pH analyses. Longissimus samples were subjected to ageing for either 2 or 16 days postmortem (Day 2, Day 16), assessed for colour, muscle fibre-type proportion (%), muscle fibre diameter (μm), water-holding capacity (purge, % and cook loss, %), Warner–Bratzler peak shear force (WBSF, N), and protein denaturation temperature using differential scanning calorimetry (DSC, peak temperature, °C). Key results SC1-LWLR had higher purge than SC2-Berk (2.85% and 1.83% respectively; standard error of the difference (SED) = 0.33; P = 0.003), higher cook loss on Day 16 (24.63% and 16.79% respectively; SED = 1.62; P = 0.017) and higher WBSF on Day 2 and Day 16 (Day 2, 30.9 N and 26.7 N respectively; Day 16, 28.6 N and 22.0 N respectively; SED = 0.98, interaction P = 0.003). SC1-LWLR had a lower proportion of Type I (10.1% vs 16.0%; SED = 0.51) and Type IIA (14.0% vs 22.0%; SED = 0.77) and a higher proportion of Type IIB (75.9% vs 62.0%; SED = 0.74) (P < 0.001 for all) fibres. SC1-LWLR had lower DSC temperatures for two peaks. SC2-Berk had higher citrate synthase activity (P = 0.003) and glycolytic potential (P < 0.001) than SC1-LWLR. Conclusions SC2-Berk longissimus had improved quality compared with SC1-LWLR pork, most likely owing, in part, to higher proportion of oxidative and intermediate fibres in the Berkshires. However, effects of differences in environmental conditions and/or processing conditions cannot be ruled out. Implications The experiment increased our understanding of how variation in supply chains and muscle fibre-type proportion can impact the production of consistently high-quality pork.

Low-oil corn distillers dried grains with solubles can be fed to pigs up to 16.5% without compromising growth and pork quality.

This study aimed to determine the maximum inclusion rate of low-oil corn distillers dried grains with solubles (DDGS) in swine diets with a focus on growth performance and pork quality. A total of 160 crossbred pigs with an initial body weight of 25.5 kg (standard deviation = 2.5) were randomly assigned to one of 5 dietary treatments in a randomized complete block design with BW and sex as blocking factors to obtain 8 replicates and 4 pigs per pen. The low-oil corn DDGS contained 26.3% crude protein, 24.5% neutral detergent fiber, and 3.7% ether extract. Five experimental diets based on the corn, soybean meal, and wheat were formulated to contain 0, 10, 20, 30, and 40% of the low-oil corn DDGS for each of 2 phases. During the overall period, average daily gain, average daily feed intake, and gain-to-feed ratio linearly decreased (p<0.05) as the low-oil corn DDGS inclusion rate increased. A one-slope broken-line analysis showed that the maximum inclusion rate of low-oil corn DDGS in swine diets without compromising gain-to-feed ratio was 16.5% during the overall period. The carcass characteristics were not affected by the inclusion of low-oil corn DDGS up to 40%. The firmness of loin and belly linearly decreased (p<0.05) as the low-oil corn DDGS inclusion rate increased. As the inclusion rate of low-oil DDGS increased, the saturated fatty acid content in both loin and pork belly linearly decreased (p<0.001), whereas the unsaturated fatty acid content linearly increased (p<0.001). The iodine value of lard also showed a linear increase (p<0.001) with increasing the low-oil corn DDGS inclusion rate. The maximum inclusion rate of low-oil corn DDGS in growing-finishing swine diets without detrimental effects on growth performance and pork quality was 16.5%.

Impacts of carob pulp (Ceratonia siliqua L.) and vitamin E on pork colour, oxidative stability, lipid composition and microbial growth

This study aimed to evaluate the impact of the dietary by-product rich in polyphenols (Carob pulp, Cp) and supra-nutritional level of vitamin (Vit) E on pork quality and shelf-life of meat stored in modified atmosphere packaging for 15 days. A total of 44 pigs (entire males and gilts, 170 ± 4.5 days of age and 127.8 ± 3.6 kg of body weight) were randomly selected from a larger group (one pig per pen). Pigs were fed ad libitum with one of four diets in a 2 × 2 factorial arrangement, with two feed inclusion levels each for Cp (0 vs. 20 %) and Vit E (30 (Low) vs. 300 IU/kg of feed (High)) for 40 days. No interactions between Cp and Vit E were detected for most variables assessed. Meat colour attributes evolved regardless of diet or sex, although metmyoglobin formation was preserved until 13 days. The Cp diets did not affect malondialdehyde nor α-tocopherol content in meat. High Vit E limited the malondialdehyde production up to 13 days and increased 1.8-fold the muscle α-tocopherol content compared to Low Vit E. The 20 %-Cp group tended to reduce total aerobic microbial count compared to 0 %-Cp group after 15 days of storage. Including Cp slightly affected the meat fatty acid (FA) profile, whereas Vit E did not modify it. Entire males presented higher content of polyunsaturated FA than gilts. Including 20 % Cp into pigs' diets does not impair meat quality, while High Vit E reduces lipid oxidation but not meat discolouration.

Eubacterium siraeum suppresses fat deposition via decreasing the tyrosine-mediated PI3K/AKT signaling pathway in high-fat diet-induced obesity.

Obesity in humans can lead to chronic diseases such as diabetes and cardiovascular disease. Similarly, subcutaneous fat (SCF) in pigs affects feed utilization, and excessive SCF can reduce the feed efficiency of pigs. Therefore, identifying factors that suppress fat deposition is particularly important. Numerous studies have implicated the gut microbiome in pigs' fat deposition, but research into its suppression remains scarce. The Lulai black pig (LL) is a hybrid breed derived from the Laiwu pig (LW) and the Yorkshire pig, with lower levels of SCF compared to the LW. In this study, we focused on these breeds to identify microbiota that regulate fat deposition. The key questions were: Which microbial populations reduce fat in LL pigs compared to LW pigs, and what is the underlying regulatory mechanism? In this study, we identified four different microbial strains, Eubacterium siraeum, Treponema bryantii, Clostridium sp. CAG:413, and Jeotgalibaca dankookensis, prevalent in both LW and LL pigs. Blood metabolome analysis revealed 49 differential metabolites, including tanshinone IIA and royal jelly acid, known for their anti-adipogenic properties. E. siraeum was strongly correlated with these metabolites, and its genes and metabolites were enriched in pathways linked to fatty acid degradation, glycerophospholipid, and glycerolipid metabolism. In vivo mouse experiments confirmed that E. siraeum metabolites curb weight gain, reduce SCF adipocyte size, increase the number of brown adipocytes, and regulate leptin, IL-6, and insulin secretion. Finally, we found that one important pathway through which E. siraeum inhibits fat deposition is by suppressing the phosphorylation of key proteins in the PI3K/AKT signaling pathway through the reduction of tyrosine. We compared LW and LL pigs using fecal metagenomics, metabolomics, and blood metabolomics, identifying E. siraeum as a strain linked to fat deposition. Oral administration experiments in mice demonstrated that E. siraeum effectively inhibits fat accumulation, primarily through the suppression of the PI3K/AKT signaling pathway, a critical regulator of lipid metabolism. These findings provide a valuable theoretical basis for improving pork quality and offer insights relevant to the study of human obesity and related chronic metabolic diseases. Video Abstract.

Effect of Bacillus amyloliquefaciens supplementation on intramuscular fat accumulation and meat quality in finishing pigs.

This study evaluated the potential of Bacillus amyloliquefaciens to improve growth performance and meat quality in finishing pigs. Thirty-two female Landrace × Duroc pigs, 21 weeks old with initial body weight 77.45±3.29 kg, were divided into two groups: a control group (basal diet) and a probiotic group (basal diet with Bacillus amyloliquefaciens at 1×109 CFU/kg). Body weight and average daily gain (ADG) were recorded at the start and at fortnight intervals for a 56-d feeding trial. At the end of the experiment, carcass traits, meat quality and intramuscular fat related gene expression of longissimus dorsi muscle were analyzed. The probiotic group showed significantly higher final body weight and D0-D56 ADG (p < 0.05). Additionally, the probiotic group had greater carcass weight, back fat thickness and marbling score (p < 0.05), while the lean meat percentage remained unchanged. Meat quality analysis revealed that the probiotic group had a higher b* value (5.47) (p < 0.05), and a lower shear value (p < 0.001), but there was no effect on the a* value and water holding capacity. Moreover, probiotic treatment increased the gene expression of fatty acid uptake and regulator, such as LPL, CD36, and SLC27A1 (p < 0.05). Our findings suggest that the supplementation of Bacillus amyloliquefaciens not only enhanced growth performance and carcass weight in finishing pigs, but also improved marbling and tenderness in the longissimus dorsi muscle through the up-regulation of lipogenic-genes related to fat accumulation. This indicates its potential as feed additive to enhance pork quality.

Overexpression of ALDOC Promotes Porcine Intramuscular and Intermuscular Fat Deposition by Activating the AKT-mTORC1 Signaling Pathway.

Skeletal muscle fat accumulation, a common complication of obesity, has garnered increasing attention. For livestock animals, intramuscular fat content is a key determinant of meat quality and directly influences consumer preferences for different meat products. However, genes effectively regulating intramuscular and intermuscular fat (IIMF) deposition remain largely unexplored. To address this gap, we employed transcriptome sequencing of muscle from pigs with high and low IIMF contents, uncovering Aldolase C (ALDOC) as a novel key gene controlling IIMF. ALDOC overexpression significantly enhanced the IIMF content both in vivo and in vitro. Mechanistic investigations revealed that ALDOC activates the AKT-mTORC1 axis to promote lipid accumulation in myotubes and intramuscular adipocytes. Notably, the mTORC1 inhibitor rapamycin abrogated ALDOC's proadipogenic effect. Our findings establish ALDOC as a novel key gene regulating IIMF deposition and identify the ALDOC-AKT-mTORC1 signaling pathway as a promising therapeutic target for treating skeletal muscle fat infiltration and improving pork quality.

The Assessment of the Possibility of Using Yellow Mealworm Powder in Chicken and Pork Pâté Production

Meat delicatessen products, including pâtés, are important for consumers’ daily diets. However, due to the complex recipe composition, pâtés can also contain allergens such as gluten. Simultaneously, powdered edible insects are increasingly used to reformulate food products. Therefore, the paper aimed to investigate the feasibility of replacing wheat flour (total content: 9% w/w) with yellow mealworm powder (3:0, 2:1, 1:2, and 0:3) in chicken and pork pâtés and determine its effect on their quality properties. The rheological properties of pâté batter, as well as texture, color parameters, and microbiological and sensory characteristics of pâtés, were assessed. All prepared pâté batters were identified as weak gels. Furthermore, all the examined pâtés met the microbiological quality requirements. Adding yellow mealworm powder to the formulation weakened the pâté structure, resulting in significantly lower shear force and increased spreadability. In addition, it led to a darker and more gray color of the pâtés. It may be seen as indicating no preservatives or as resembling a typical pork pâté. It has been demonstrated that the complete replacement of wheat flour with insect powder significantly reduced the sensory quality of chicken and pork pâtés.

Quality and Processability of Meat in Polish Native Pigs – A Review

Abstract The primary aim of pig breeding efforts is to produce animals characterized by outstanding performance, including also fattening and slaughter performance traits. However, improved carcass leanness and reduced carcass fatness, especially intramuscular fat content, have led to a deterioration of pork quality and processability. Due to the growing frequency of meat defects and the limited potential use of such meat in the production of premium products this constitutes a considerable problem for the meat industry. The breeds superior in terms of meat quality are native pig breeds, such as those kept in Poland, i.e. Pulawska (Pul), Zlotnicka Spotted (ZS) and Zlotnicka White (ZW) pigs. The aim of this paper is to present a review of research results concerning quality and processability of meat produced by the Polish native pig breeds. The presented results indicate that pigs of local breeds exhibit a low level of performance traits (daily gain, carcass leanness, backfat thickness) while maintaining very good parameters of meat quality and processability (muscle composition and physical properties, fatty acids profile, sensory traits). Thus, they are used as a source material for premium products. In view of the small size of local populations and higher production costs in Poland it is a niche production. Therefore, the current aim of breeding indigenous breeds is both to maintain a safe population size and genetic diversity and to increase popularity of their meat and processed meat products among consumers. This objective is attained, among other things, thanks to efforts to reduce cost of their production through optimization of environmental conditions and wider use of less expensive traditional feed formulations, which make it possible to fully utilize the potential of local pork resources.

Preparation and characterization of porous corn starch-based antibacterial sustained-release intelligent film

A novel porous corn starch-based antibacterial sustained-release intelligent film was prepared with the porous corn starch as the substrate, purple corn cob anthocyanin (PCA) as the indicator, and tangerine peel essential oil as the antibacterial agent, and its properties were studied. The results showed that the porous corn starch-based antimicrobial sustained-release indicator film had good mechanical strength, surface hydrophobicity and light transmittance. The tensile strength of the sustained-release indicator film (PLSt-12) prepared by porous corn starch with an enzymatic hydrolysis time of 12 h was 14.35 MPa and the elongation at break was 6.55 %. The water contact angle was 89.10°, and the water vapor transmittance was 6.62 × 10−4 g·mm2·s−1·Pa−1. The PLSt-12 was brown at pH 10 and had a sensitive color response. The PLSt-12 reduced the release rate of anthocyanins by 25.01 %, and the sustained-release mechanism was non-Fick diffusion. It showed a significant color change when the pork quality deteriorated, which can be used to monitor the freshness of the pork. This type of antibacterial sustained-release intelligent film had considerable application potential in indicating food freshness.

Differential chromatin accessibility and Gene Expression Associated with Backfat Deposition in pigs

BackgroundBackfat serves as a vital fat reservoir in pigs, and its excessive accumulation will adversely impact pig growth performance, farming efficiency, and pork quality. The aim of this research is to integrate assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) and RNA sequencing (RNA-seq) to explore the molecular mechanisms underlying porcine backfat deposition.ResultsATAC-seq analysis identified 568 genes originating from 698 regions exhibiting differential accessibility, which were significantly enriched in pathways pertinent to adipocyte differentiation and lipid metabolism. Besides, a total of 283 transcription factors (TFs) were identified by motif analysis. RNA-seq analysis revealed 978 differentially expressed genes (DEGs), which were enriched in pathways related to energy metabolism, cell cycle and signal transduction. The integration of ATAC-seq and RNA-seq data indicates that DEG expression levels are associated with chromatin accessibility. This comprehensive study highlights the involvement of critical pathways, including the Wnt signaling pathway, Jak-STAT signaling pathway, and fatty acid degradation, in the regulation of backfat deposition. Through rigorous analysis, we identified several candidate genes (LEP, CTBP2, EHHADH, OSMR, TCF7L2, BCL2, FGF1, UCP2, CCND1, TIMP1, and VDR) as potentially significant contributors to backfat deposition. Additionally, we constructed TF-TF and TF-target gene regulatory networks and identified a series of potential TFs related to backfat deposition (FOS, STAT3, SMAD3, and ESR1).ConclusionsThis study represents the first application of ATAC-seq and RNA-seq, affording a novel perspective into the mechanisms underlying backfat deposition and providing invaluable resources for the enhancement of pig breeding programs.

A review of porcine skeletal muscle plasticity and implications for genetic improvement of carcass and meat quality*

Skeletal muscle is characterized by a remarkable plasticity to adapt to stimuli such as contractile activity, loading conditions, substrate supply or environmental factors. The existing knowledge of muscle plasticity along with developed genetic and genomic technologies, have enabled creating animal breeding strategies and allowed for implementing agriculturally successful porcine genetic improvement programs. The primary focus of this review paper is on pig skeletal muscle plasticity as it relates to genetic improvement of desirable carcass composition and pork quality traits. Biological constraints between practically realized breeding objectives, pig skeletal muscle biology, and pork quality are also discussed. Future applications of genetic and genomic technologies and plausible focus on new breeding objectives enhancing pork production sustainability are proposed as well.

DIFFERENCES IN CARCASS COMPOSITION OF MALE, CASTRATED, AND IMMUNOCASTRATED PIGS: A narrative literature review

The quality of pork is dependent on factors of retail and consumer interest, including appearance, shelf life, as well as tenderness and flavor. One of the factors determining the quality of the animal concerns its castration. Castration of pigs is a procedure carried out to control the odor of the meat and to guarantee the complete quality of the animal for consumption. Therefore, understanding its effects on pig production is essential to have a quality animal and increasingly higher production levels. In this sense, the general objective of this study is to carry out an analysis of the differences in the composition of the pig carcass: male, castrated and immunocastrated through a bibliographical review. The specific objectives were to elucidate the carcass characteristics of male, castrated and immunocastrated pigs and verify the impact of castration on the quality of the animal carcass. Through this study it was possible to conclude that immunocastrated pigs stand out in terms of carcass yield compared to surgically castrated males and intact males, due to the sexual odor, the quality of the meat, the thickness of the bacon and in its entirety.

Genome-Wide Analysis Reveals Copy Number Variant Gene TGFBR3 Regulates Pig Back Fat Deposition.

BFT is closely related to meat quality and lean meat percentage in pigs. The BFT traits of European LW pigs significantly differ from those of Chinese indigenous fatty MZ pigs. CNV is a prevalent genetic variation that plays an important role in economically important traits in pigs. However, the potential contribution of CNV to BFT in LW and MZ pigs remains unclear. In this study, whole-genome CNV detection was performed using next-generation sequencing data from LW and MZ pigs, and transcriptome data from back fat tissue of 180-day-old LW and MZ pigs were integrated for expression quantitative trait loci (eQTL) analysis. We identified a copy number variation in the TGFBR3 gene associated with BFT, showing a dose effect between the genome and transcriptome levels of the TGFBR3 gene. In porcine preadipocytes, TGFBR3 expression continuously increased during differentiation. Knockdown of TGFBR3 using specific siRNA inhibited preadipocyte differentiation and proliferation. Our study provides insights into the genetic regulation of pork quality and offers a theoretical basis for improving carcass quality by modulating BFT in pigs.

FNDC5 IS THE KEY MOLECULE TO INHIBIT MUSCLE FIBER DEVELOPMENT IN TIBETAN PIGS

Differences in muscle fiber development between Tibetan and Yorkshire pigs determine their performance in terms of meat quality, taste, and food value. To investigate the molecular regulation of muscle fiber development by fibronectin type III domain-containing protein 5 (FNDC5), a preliminary study of FNDC5 gene expression in the longissimus dorsi muscle and Leg muscle tissues of Tibetan and Yorkshire Pigs was conducted using RT–qPCR and western blotting. Muscle tissues were sectioned and stained to observe the muscle fiber diameter and area under a microscope. The mRNA and protein expression levels of FNDC5, and the diameter and area of muscle fibers in the longissimus dorsi muscle and Leg muscle tissues of Tibetan pigs were significantly lower than those in Yorkshire Pigs. The results imply that FNDC5 negatively regulates muscle fiber diameter in pigs. The role of FNDC5 in pork quality has important implications for improving pork production efficiency, pork quality, and the sustainable development of the livestock industry. Keywords: Pig; FNDC5; Gene expression.

Effects of maternal contact and positive human contact during lactation on pork quality: Positive human contact to piglets during lactation improves pork loin muscle pH

Enhancing stress resilience through the early life period in pigs could potentially improve pork quality. It was hypothesised that pigs receiving maternal contact or positive human contact during lactation would have improved carcass and pork quality. Seventy-nine mixed-sex pigs were selected from a 2 × 2 factorial randomised block design for treatments maternal contact (MC+) / reduced maternal contact (MC-); and positive human contact (HC+) / control (HC-). Modified farrowing crates were utilised to reduce maternal contact (MC-). Litters in the HC+ treatment received five minutes of daily positive human interaction (stroking). Treatments ceased at 22 days of age (weaning) and pigs were slaughtered after 21 weeks of age. The m. longissimus thoracis et lumborum pH was higher in HC+ than HC- pigs (P < 0.05) during chilling, from 90 min post slaughter. No HC effects (P > 0.05) were observed for cortisol or haptoglobin concentration, hot carcass weight, P2 backfat, carcass scratches, colour, drip loss, cook loss and shear force. MC+ tended (P < 0.086) to increase carcass weight, P2 and carcass scratch score compared to MC-, but no further impacts were observed. The impact of positive human contact during early life was observed 20+ weeks after treatment with reduced pH decline, potentially indicating a reduction in pre-slaughter stress, however there were no further impacts on pork quality. There is evidence that maternal contact is important for lifetime growth performance of pigs but the impacts on stress resilience are less apparent.

Effect of the addition of different forms of rosemary (Rosmarinus officinalis L.) on the quality of vacuum-packed minced pork

Abstract Introduction Apart from their antioxidant activity, plant-derived bioactive compounds can also positively affect the quality of meat and meat products by improving their sensory and microbiological properties and preventing discolouration. The aim of this study was to determine how the addition of different forms of rosemary improved the quality of pork. Material and Methods Minced pork samples were divided into a control sample without additives (C) and three experimental samples with certified additives (15 mg/kg of meat each), i.e. rosemary oleoresin (ROL), extract (REX) and essential oil (REO). Each was further divided into three subsamples; the first was evaluated before storage, and the second and third were evaluated after respective 7- and 14-day vacuum-packed storage at 2°C. The TBARS value was expressed as mg of malondialdehyde (MDA) per kg of meat. Colour was determined based on the values of the standard colour space values of L* (lightness), a* (redness) and b* (yellowness) as well as C* (chroma) and h° (hue angle). Sensory attributes of the samples were evaluated on a nine-point scale. The pour-plating procedure was used for the enumeration of Pseudomonas, mesophilic lactic acid bacteria, psychrotrophic bacteria and rods of the Enterobacteriaceae family. Within each bacterial group, the most common colonies were identified by matrix-assisted laser desorption and ionization (MALDI). Results Lipid oxidation was most effectively inhibited by REO. The addition of ROL and REO to pork lightened its colour. Meat with REO had stronger redness, whereas meat with ROL had stronger yellowness. The addition of REX affected the sensory properties of pork most beneficially. Neither Enterobacteriaceae nor Pseudomonas spp. were detected in REO pork, which also contained lower counts of lactic acid bacteria than group C pork. Conclusion The results of this study indicate that rosemary has antioxidant and antimicrobial properties, and may improve the colour and sensory attributes of pork. The effect exerted by rosemary on meat quality may vary depending on the physical form of the additive.

Research progress in pork quality and resistance to porcine reproductive and respiratory syndrome in south China and creation of germplasm resources

Research progress in pork quality and resistance to porcine reproductive and respiratory syndrome in south China and creation of germplasm resources

Muscle growth differences in Lijiang pigs revealed by ATAC-seq multi-omics.

As one of the largest tissues in the animal body, skeletal muscle plays a pivotal role in the production and quality of pork. Consequently, it is of paramount importance to investigate the growth and developmental processes of skeletal muscle. Lijiang pigs, which naturally have two subtypes, fast-growing and slow-growing, provide an ideal model for such studies by eliminating breed-related influences. In this study, we selected three fast-growing and three slow-growing 6-month-old Lijiang pigs as subjects. We utilized assay for transposase-accessible chromatin with sequencing (ATAC-seq) combined with genomics, RNA sequencing, and proteomics to screen for differentially expressed genes and transcription factors linked to increased longissimus dorsi muscle volume in Lijiang pigs. We identified 126 genes through ATAC-seq, including PPARA, TNRC6B, NEDD1, and FKBP5, that exhibited differential expression patterns during muscle growth. Additionally, we identified 59 transcription factors, including Foxh1, JunB, Mef2 family members (Mef2a/b/c/d), NeuroD1, and TEAD4. By examining open chromatin regions (OCRs) with significant genetic differentiation, genes such as SAV1, CACNA1H, PRKCG, and FGFR4 were found. Integrating ATAC-seq with transcriptomics and transcriptomics with proteomics, we identified differences in open chromatin regions, transcription, and protein levels of FKBP5 and SCARB2 genes in fast-growing and slow-growing Lijiang pigs. Utilizing multi-omics analysis with R packages, we jointed ATAC-seq, transcriptome, and proteome datasets, identifying enriched pathways related to glycogen metabolism and skeletal muscle cell differentiation. We pinpointed genes such as MYF6 and HABP2 that exhibit strong correlations across these diverse data types. This study provides a multi-faceted understanding of the molecular mechanisms that lead to differences in pig muscle fiber growth.

Organic rearing of non-castrated male pigs: welfare indicators, carcass traits, pork quality and boar taint in Duroc and Pietrain crossbreds

The main principles of organic farming as presented by the European organisation for organic food and farming are health, ecology, fairness and care, but the intrinsic quality of products is also important for consumers. Pig genotype was tested as a lever to improve animal welfare and pork quality (meat tenderness, processing ability) of organic, non-castrated males while controlling the risk for boar taint. Non-castrated Large White × Duroc (D, n = 47) or Large White × Pietrain NN (P, n = 34) males were involved in two batches, each including one group of pigs per genotype. Each group was reared in a pen from the same building on deep straw bedding (1.3 m2/pig), with a feeding zone (0.2 m2/pig) and an outdoor area (1.0 m2/pig), from 28 kg BW until slaughter at ca. 125 kg BW. All pigs received ad libitum the same growing and finishing diets, and hay. Overall, health and welfare indicators showed few problems, but the proportions of pigs with skin scratches, and tail lesions at the end of the finishing period, were lower in D than in P pigs (P < 0.05). Growth rate and final BW did not differ between genotypes. The D pigs had lower carcass lean meat content (P < 0.001) and relative proportions of ham and loin (P ≤ 0.01), and higher proportions of belly and backfat (P ≤ 0.001) than P pigs. Compared to P, loin (Longissimus muscle) of D pigs was less light and exudative and had higher chroma (P < 0.05), but pH 24 h and glycolytic potential did not differ. Loin meat of D pigs had higher intramuscular fat content (P < 0.001) and tended to have a lower shear force (P = 0.09), but cooking loss did not differ. In the ham muscles, D pigs had higher chroma than P pigs in the Gluteus medius, whereas pH 24 h did not differ in the Gluteus medius and Semimembranosus. D pigs had higher backfat concentrations of androstenone (P < 0.001), and skatole and indole (P < 0.05) than P pigs, suggesting a higher risk of rejection by consumers due to boar taint. However, only one D carcass was detected as tainted by human nose test. Altogether, organic farming of non-castrated Duroc crossbred males appears to be favourable for animal welfare, technological and several sensory pork properties provided that the risk of undesirable odours is limited through management practices.