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At least 19 recordsLinked to original sources
PubMed2026

Comparative transcriptome analysis of Qinchuan and Wagyu cattle reveals lnc11599 as a negative regulator of intramuscular fat deposition.

BACKGROUND: Intramuscular fat (IMF) content is a critical factor determining beef quality, influenced by various factors including breed and age. However, the regulatory role of long non-coding RNAs (lncRNAs) in IMF deposition remains unclear. METHODS: This study investigated IMF deposition in the longissimus dorsi muscle of one- and two-year-old Qinchuan and Wagyu cattle through histological examination and fat content measurement. Based on transcriptome sequencing data of intramuscular fat tissue, differential expression analysis and weighted gene co-expression network analysis (WGCNA) were performed to identify lncRNAs associated with IMF deposition. The effects of a key candidate lncRNA on the adipogenic differentiation of cattle intramuscular preadipocytes were further examined. RESULTS: Results showed that Wagyu cattle exhibited stronger IMF deposition capacity than Qinchuan cattle across all age groups, with IMF content increasing with age in both breeds. We identified 7,910 lncRNAs from intramuscular fat tissue transcriptome data, including 6,455 novel lncRNAs. Through integrated differential expression analysis and WGCNA, 88 lncRNAs closely associated with IMF deposition were screened from two-year-old Qinchuan and Wagyu cattle. Notably, lnc11599 was significantly upregulated in Qinchuan cattle intramuscular fat tissue, but its expression decreased during intramuscular preadipocyte differentiation. Functional experiments demonstrated that lnc11599 knockdown enhanced adipogenic differentiation capacity, manifested as a highly significant increase in lipid accumulation, upregulation of key adipogenic genes at the mRNA level, together with increases in total fatty acid content and unsaturated fatty acid proportion. CONCLUSIONS: This study established the lncRNA expression profiles in intramuscular fat tissue of Qinchuan and Wagyu cattle across different developmental stages, and demonstrated that lnc11599 acts as a negative regulator of intramuscular fat deposition. These findings provide new directions for elucidating the mechanisms of cattle IMF deposition and offer potential targets for genetic improvement of beef quality.

Animals↗
PubMed2026

Functional characterization of lncIMF_17214 in regulating intramuscular fat deposition of yellow-feathered broilers.

Intramuscular fat (IMF) content and lipid composition are key determinants of both the nutritional value and sensory attributes of poultry meat, yet the underlying regulatory mechanisms remain insufficiently elucidated. In this study, triglyceride (TG) content was employed as a quantitative phenotypic proxy to dissect the molecular basis of IMF deposition in yellow-feathered broilers. By integrating TG phenotypic data from 315 individuals with transcriptomic profiles and whole-genome resequencing datasets, a TG-associated long noncoding RNA (lncRNA), lncIMF_17214, was identified. Functional characterization revealed that lncIMF_17214 functions as a negative regulator of lipid deposition. Specifically, its knockdown led to significant increases in TG and total cholesterol concentrations, promoted lipid droplet accumulation, and decreased shear force in breast muscle, whereas its overexpression elicited the opposite effects. Mechanistically, lncIMF_17214 interacts with the RNA-binding protein CNBP, forming a regulatory complex that inhibits lipid accumulation. Furthermore, liver-directed overexpression increased the abundance of lncIMF_17214 in plasma exosomes, while liver-directed manipulation was associated with changes in hepatic and breast-muscle lipid deposition; direct exosome-mediated transfer to intramuscular adipocytes remains to be established. Transcriptomic profiling coupled with pathway enrichment analyses demonstrated that lncIMF_17214 predominantly influences steroid biosynthesis, unsaturated fatty acid metabolism, and peroxisome proliferator-activated receptor (PPAR) signaling pathways. This suggests that it may be involved in the regulation of these pathways, although the underlying molecular mechanisms remain to be further elucidated. Collectively, these findings define a lncIMF_17214-centered regulatory axis linking intracellular and systemic lipid metabolism and provide a robust molecular framework for the targeted improvement of meat quality traits in yellow-feathered broilers.

Breast muscle↗
PubMed1992

Principles of ultrasound and measurement of intramuscular fat.

A review of basic engineering concepts of ultrasound is presented for the layperson with implications toward the use of ultrasound on beef animals. The use of ultrasound for determining quality traits such as percentage of intramuscular fat is discussed in detail. Results of both A-mode and B-mode preliminary investigations are presented. Preliminary results show that intramuscular fat may be predicted using an A-mode transducer coupled with frequency analysis.

Adipose Tissue↗
PubMed2026

Intramuscular Fat Infiltration and Knee Osteoarthritis: A Systematic Review and Meta-Analysis.

BACKGROUND: Intramuscular fat infiltration (IMFI) is considered to be closely associated with knee osteoarthritis (KOA); however, its overall association, muscle-specific involvement, and clinical relevance remain unclear. OBJECTIVE: To quantify the association between IMFI and KOA, identify affected muscle groups, and evaluate prognostic value. METHODS: We searched PubMed, Web of Science, Scopus, and Embase up to December 2025 for observational studies. Two reviewers independently screened, extracted data, and assessed bias (NOS/JBI). Pooled standardized mean differences (SMDs) were calculated using random-effects models, with subgroup and sensitivity analyses. RESULTS: Seventeen studies were included. IMFI was significantly higher in KOA patients than controls (SMD = 0.63, 95% CI 0.41-0.85, I2 = 84.7%). Anatomically, the anterior thigh muscles (rectus femoris, vastus lateralis, vastus medialis) demonstrated a significant pooled effect (SMD = 0.96, 95% CI 0.66-1.25, I2 = 3.2%) and showed the strongest pooled association, whereas posterior, medial, and composite measures did not demonstrate significant associations. At the individual muscle level, a single study reported a notable association for the semimembranosus (SMD = 1.25, 95% CI 0.57-1.93); however, this finding is based on limited evidence and requires confirmation in future studies. Subgroup by imaging modality: CT demonstrated a significant association (SMD = 0.59, 95% CI 0.28-0.90), while MRI and ultrasound did not show significant associations. Elevated IMFI was also associated with reduced muscle strength, higher KOA incidence, structural progression, and increased knee replacement risk. CONCLUSION: A moderate positive association exists between IMFI and KOA, with notable muscle-specific heterogeneity. Anterior thigh muscles show the strongest pooled association, whereas individual muscle findings require further confirmation. These findings suggest that IMFI may represent a promising potential marker warranting further prospective investigation for risk stratification, though causality and its role in modifying disease progression remain to be established.

Humans↗
PubMed2026

FOS Regulates Myogenic and Adipogenic Differentiation via Extracellular Matrix Signaling.

In the livestock industry, intramuscular fat deposition is a key factor influencing meat tenderness and flavor. Although FOS (Fos proto-oncogene, AP-1 transcription factor subunit) has been implicated in the regulation of cell proliferation and differentiation, its differential roles in myogenic and adipogenic regulation remain unclear. In this study, we revealed that FOS markedly enhanced myogenic differentiation while inhibiting adipogenic differentiation in muscle stem cells, indicating that it exerts distinct effects on muscle development and intramuscular fat deposition. Mechanistically, FOS modulated extracellular matrix signaling by regulating FAK and PXN phosphorylation, acting as a molecular regulator between the muscle and fat lineages. Furthermore, exon SNPs in FOS were associated with slaughter weight and backfat thickness, and the mutant genotypes weakened its antiadipogenic effect. Collectively, these findings suggest that FOS is an important regulator of myogenic and adipogenic differentiation and is a potential candidate gene for the genetic improvement of meat quality traits.

Animals↗
PubMed1992

Genetic analyses of growth, real-time ultrasound, carcass, and pork quality traits in Duroc and Landrace pigs: I. Breed effects.

Knowledge of breed effects on carcass and pork quality traits is required to develop commercial crossbreeding programs that emphasize product quality. A 2 x 2 diallel mating system involving Landrace and Duroc pigs was used to estimate individual heterosis, direct breed effects and reciprocal cross differences for post-weaning growth, real-time ultrasound, carcass, and pork quality traits. Data from 5,649 pigs and 960 carcasses representing 65 and 49 sires, respectively, were analyzed assuming animal models. Duroc-sired pigs had 2.1 cm shorter carcasses with 7.3 mm less 10th rib backfat (BF), 4.4 cm2 larger longissimus muscle area (LMA), yielded 2.1 kg more estimated fat standardized lean (FSL), gained 16.5 g more estimated lean per day of age (LDOA), and had 1.0% less water (PWAT) and 1.9% more intramuscular fat (IMF) in the longissimus muscle than did Landrace-sired pigs (P less than .01), adjusted to an off-farm live weight of 111 kg. Reciprocal cross differences were detected for BF, LMA, FSL, LDOA and for subjective marbling, firmness, and muscling scores (P less than .01). Durocsired F1 barrows had 6.3 mm less BF and 5.9 cm2 larger LMA, yielded 3.2 kg more FSL, gained 22.3 g more LDOA, and had less marbling in the longissimus muscle and heavier ham muscling than reciprocal cross barrows. Heterosis estimates (P less than .05) were 27.6 g/d (3.2%) for ADG, -5.8 d (-3.6%) for off-test age, 2.7 cm (3.4%) for carcass length, 1.5 kg (7.2%) for FSL, 14.7 g (5.7%) for LDOA, -.07 (-3.6%) for muscle color, -.5% (-13.2%) for IMF, and .3% (.3%) for PWAT. Breed effects were not detected (P greater than .10) for muscle pH, cooking loss, shear value, and water-holding capacity or for eating quality traits. Reciprocal cross differences suggest an advantage in using the Duroc as a terminal sire, but improved carcass composition and higher intramuscular fat did not seem to affect eating quality traits.

Adipose Tissue↗
PubMed1992

Seasonal variation in venison quality of mature, farmed red deer stags in New Zealand.

Two studies involving 20 red deer (Cervus elaphus) stags were conducted to determine the effects of season on venison quality. In each study, five sexually mature red deer stags were slaughtered immediately preceding the rut (autumn) and five were slaughtered after the rut. Stags slaughtered postrut had lower carcass weights (25 to 30%) than those slaughtered prerut. Average bodywall thickness measurements above the 12th rib (an indicator of fat thickness) were approximately 31 mm prerut compared with 3 to 7 mm postrut. Individual muscles and retail cuts (which included subcutaneous and intermuscular fat) were heavier in prerut carcasses. There were significant decreases in intramuscular fat in both the longissimus muscle and the semimembranosus muscle. Postrut longissimus muscle steaks appeared brighter and(or) fresher than the other groups; color acceptability was negatively correlated (P less than .05) with fat content. Prerut streaks from both muscles were more tender than postrut steaks from those muscles. Overall desirability and tenderness were highly correlated (r = .94 and .82 for longissimus muscle and semimembranosus muscle, respectively).

Animals↗
PubMed1992

Performance, plasma hormones, histochemical and biochemical muscle traits, and meat quality of pigs administered exogenous somatotropin between 30 or 60 kilograms and 100 kilograms body weight.

Forty-five Large White barrows were injected daily i.m. with either excipient from 30 to 100 kg BW (CTRL), excipient from 30 to 60 and porcine somatotropin (pST; 100 micrograms/kg BW) from 60 to 100 kg BW (pST-60), or pST (100 micrograms/kg BW) from 30 to 100 kg BW (pST-30). Somatotropin accelerated overall growth rate (+4 and +9% for pST-60 and pST-30, respectively), increased longissimus (+10.3 and +14.7%) and semitendinosus (+17 and +13%) muscle weights, and decreased backfat (-49 and -58%) and leaf fat (-49 and -53%) weights. The administration of pST resulted in a similar increase in muscle fiber size for all fiber types in both longissimus (LM) and semispinalis (SS) muscles (+21%). Somatotropin had otherwise little effect on muscle fiber types and biochemical traits of LM, whereas dramatic changes were observed in SS. The relative area occupied by Type IIB fibers was increased (+22 and +29%) and that of Type I fibers was decreased (-10 and -15%). In pST-30 animals, myosin ATPase activity (+15%) and native myosin fast isoform proportion (+10%) were augmented, and energy metabolism was more glycolytic (lactate dehydrogenase: +25%) and less oxidative (citrate synthase: -13%; beta-hydroxyacyl-CoA dehydrogenase: -21%). Compared to CTRL animals, administration of pST increased muscle water concentration (LM: +.8 and +1.1%: SS: +3.3 and +3.3%) and decreased intramuscular fat (LM: -29 and -27%; SS: -39 and -50%). The pH measured 45 min and 24 h postmortem, glycogen content, reflectance, and index of light diffusion were mostly not affected by pST treatment. In conclusion, pST had a very favorable effect on growth performance without any important effect on meat quality traits except for the reduction in intramuscular lipid content. The results indicated that the effects of pST on muscular histochemical and biochemical characteristics were different in LM and SS muscles.

Adipose Tissue↗
PubMed1978

Fatty acid synthesis in mice during the 24hr cycle and during meal-feeding.

Fatty acid synthesis was measured in liver, adipose tissue and the rest of the carcass in vivo, by measuring the incorporation of 3H from 3H2O. The maximum rate of synthesis during the 24 hr cycle occurred at 21.00-22.00 hr. At all times, the rest of the carcass was the major synthetic site and adipose tissue only made a significant contribution at the time of maximum synthesis. The rate of fatty acid synthesis in meal-fed mice was increased during the meals by 5-8 fold in the rest of the carcass, 10-fold in liver, and 30-60-fold in adipose tissue over the rate of synthesis in the immediate pre-prandial period. It is suggested that one reason for the higher rates of fatty acid synthesis in the rest of the carcass could be the activity of the intramuscular fat pads.

Adipose Tissue↗
PubMed1978

Radiologic soft tissue shadows in the pelvis: another look.

In patients with adequate amounts of intramuscular fat, the normal contours of the muscles of the pelvic floor and side-walls may be visualized on plain radiographs. Knowledge of the relationships of these muscles to surrounding structures has been facilitated by computed tomography. Obliteration of the medial margin of the psoas muscle with an attendant soft tissue mass implies pathology in the region of the medial chain of external iliac lymph nodes; similarly, obliteration of the obturator internus shadow suggests internal iliac adenopathy. Nonnodal masses in these regions can cause similar radiographic abnormalities. The normal shadow of the piriformis muscle may simulate external iliac adenopathy. Pitfalls which may lead to overinterpretation are discussed.

Adipose Tissue↗
PubMed1990

A technique for the combination of clearing, staining, and injecting small mammals.

A combined method for clearing soft tissues, staining cartilage and bone, and injecting the vascular system of small mammals was developed using Mus musculus (house mouse). Mammalian muscle tissue remains milky or even opaque after "clearing" by previous techniques due to the relatively high content of intramuscular fat. A method employing chloroform-ethanol successfully renders soft tissues of mammalian specimens translucent without damaging or bleeding color from the latex injected in the circulatory system. Resulting specimens yield an excellent view of the skeletal system and the injected vascular system without obstruction by opaque tissues or disruption by physical removal of connective tissue.

Animals↗
PubMed1977

Distribution of amikacin in serum, muscle, and fat in children after a single intramuscular injection.

Amikacin concentrations in serum, muscle, and fat were determined in 41 children after intramuscular administration of 7.5 mg/kg of body weight. At 1.5 h amikacin reached peak concentrations in serum (mean value, 14.9 mug/ml) as well as in muscle (2.2 mug/g) and fat (1.89 mug/g) tissue; from then on all concentrations declined. Amikacin concentrations exceeded 1 mug/g in muscle for at least 3 h and in fat for at least 4 h.

Adipose Tissue↗
PubMed1976

Effects of treatment of whole fat soybeans or soy flour with formaldehyde to protect the polyunsaturated fatty acids from biohydrogenation in the rumen.

Full-fat, ground soy flour (GSF) was treated with 37% formaldehyde (HCHO) and evaluated by in vitro and in vivo criteria to determine the protection afforded linoleic acid against ruminal biohydrogenation when the materials described above were fed as a protein supplement to rations for growing lambs. The supplements compared were soybean meal (SBM), uked for 2 hours. Organoleptic evaluations were conducted to determine if any flavor differences in meat from lambs fed these supplements could be detected. Excellent protection of linoleic acid, the major polyunsaturated fatty acid in soybeans, was noted both in vitro and in vivo. Rump, shoulder, kidney knob and omental fat depots of lambs fed the HCHO treated GSF ration had significantly more linoleic acid than lambs fed untreated GSF while lambs fed untreated GSF had significantly, more linoleic acid in their fat depots than lambs fed SBM. Linoleic acid content of intramuscular (loin) fat from lambs fed HCHO treated GSF was not significantly different from lambs fed untreated GSF, but lambs fed untreated GSF had significantly more loin linoleic acid than lambs fed SBM. No significant differences were noted in daily feed intake, feed efficiency or average daily gain for lambs fed growing-finishing rations containing any of the products tested as the protein supplement. A taste panel could not detect any differences in flavor of ground loin among any of the treatments.

Adipose Tissue↗
PubMed1977

Analysis of 4-methyloctanoic acid and other medium chain-length fatty acid constituents of ovine tissue lipids.

Medium chain-length (C6-C9) fatty acids in depot, intramuscular, kidney, and liver lipids from pasture-fed sheep and subcutaneous and intramuscular lipids from barley-fed sheep were analyzed with emphasis on the 4-methyloctanoic acid (hircinoic acid) content. Within individual animals, the level of hircinoic acid in the subcutaneous fat was usually higher than that either in the deeper depot fats or in the intramuscular fat. Variation of hircinoic acid levels between animals was greatest in the subcutanous fat and least in the perinrphric fat. There were usually higher levels of both branched and odd carbon chain fatty acids in the lipids of barley-fed sheep than in the corresponding lipids of pasture-fed sheep.

Adipose Tissue↗
PubMedDate not supplied

[The indices of the mass and lipids of sections of the heart in cadavers in chronic alcoholism, alcoholic cardiomyopathy and ethanol poisoning].

Alcohol abuse involves heart mass increment at the expense of epicardial fat. Epicardial fat mass and the content of intramuscular lipids are the highest in alcoholic cardiomyopathy. Since epicardial fat mass increase is in direct correlation with the elevation of lipid content in the heart muscle proper, detection of a large mass of epicardial fat at autopsy permits a conclusion on myocardial obesity.

Alcoholic Intoxication↗
PubMed1979

The penetrability of cephazolin into the subcutaneous fat and skeletal muscle of ischaemic lower limbs with atherosclerotic disease.

Seventeen patients with atherosclerotic disease, who were undergoing arterial reconstruction or amputation of the lower limb, had 2 g cephazolin injected per-operatively in two equal doses by intramuscular and intravenous routes. Samples of subcutaneous fat and skeletal muscle from the ischaemic leg, and serum were collected during the operation for assay of cephazolin content. The mean cephazolin levels in the serum, skeletal muscle and subcutaneous fat were found to be well above the minimum inhibitory concentrations required for most important Gram-positive and Gram-negative pathogens.

Adipose Tissue↗
PubMed1991

Nutritional and endocrinological manipulation of lean deposition in forage-fed steers.

The effect of supplementing grass silage with fishmeal on growth, muscle composition and the rate of muscle protein synthesis was investigated in young Friesian steers with and without oestradiol implants. The effect of the beta-adrenergic agonist cimaterol was simultaneously investigated in animals fed on silage alone. Treatments lasted for 9 or 10 weeks. Fishmeal supplementation significantly increased animal growth rates (P less than 0.001) and the weights of three dissected muscles (P less than 0.001) compared with the silage-fed controls. These effects were further enhanced in animals also implanted with oestradiol. Muscle weights expressed as a proportion of body-weight were increased by fishmeal, suggesting that protein deposition had been enhanced. No further increase in the proportional muscle weights was obtained with oestradiol. Muscle dry matter content tended to be increased in both implanted and non-implanted animals receiving fishmeal compared with controls, but the proportions of protein, fat and ash were relatively constant. The intramuscular lipid composition was slightly altered by fishmeal. Muscle protein fractional synthetic rates (FSR), measured by continuous infusion of [3H]tyrosine, were increased by fishmeal in all three muscles of both implanted and non-implanted animals. There were no differences, however, due to oestradiol, over non-implanted fishmeal animals. This suggests that oestradiol may increase muscle accretion by reducing protein degradation rate. Cimaterol significantly increased longissimus dorsi (P less than 0.05) and vastus lateralis (P less than 0.01) muscle weights but had no effect on semitendinosus muscle weight or live-weight gain. The proportion of protein was increased (P less than 0.001) and the fat content reduced (P less than 0.05) in all three muscles but intramuscular lipid composition was not markedly affected. Whilst methylhistidine: creatinine excretion was reduced by cimaterol, FSR were increased in the l. dorsi and v. lateralis muscles suggesting beta-agonists have effects on both protein synthesis and protein degradation.

Adrenergic beta-Agonists↗