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PubMed2004

[Comparative study on lipogenic and lipolytic gene expression in intramuscular fat tissue between growing Erhualian and large white pigs].

To investigate the mechanism of difference in intramuscular fat deposition between Erhualian and Large White pigs,single tube relative-quantitative RT-PCR method was used to investigate the development patterns of lipogenic (ACX, LPL, ME) and lipolytic (HSL) gene expression with 18S internal standard control. Sixteen Large White boars and twenty Erhualian boars were selected and raised according to normal nutrition standard respectively. The animals were selected randomly and slaughtered at 15 kg, 40 kg, 60 kg and 90 kg for Large White pigs and at 18 kg, 40 kg, 60 kg, 80 kg and 90 kg for Erhualian pigs respectively; with four animals of each breed at each time. The supraspinatus and semimembranosus muscles were removed for total RNA extraction and longisimus dorsi muscle for intramuscular fat (IMF) analysis using ether extract method. The results showed: (1) The property of IMF between Erhualian and Large White boars was similar during early growing period (before 40 kg) (P > 0.05) ,thereafter, IMF level of Erhualian boars increased dramatically to 4% at 60 kg and over 5% at 90 kg while Large White boars kept steadily at about 2% (P < 0.05); (2) The pattern of lipogenic and lypolytic gene expression was similar between semimembranosus and supraspinatus muscle in each breed; (3) The tendency for LPL and ME mRNA expression coincided with that of IMF development among 20 approximately 60 kg in Erhualian pigs. The results suggest that the development of IMF between 20 kg and 60 kg in Erhualian pigs may play a meaningful role in deposition of IMF,and that the expression of ME and LPL mRNA may contribute to fast sediment of IMF in Erhualian pigs.

Adipose Tissue↗

PubMed1998

Comparison of four real-time ultrasound systems that predict intramuscular fat in beef cattle.

Eighty-one crossbred steers were used to evaluate four commercially available ultrasound systems that predict intramuscular fat. The software systems represented included Animal Ultrasound Services, Inc., Ithaca, NY; CPEC, Oakley, KS; Critical Vision, Inc., Atlanta, GA (CVIS); and Classic Ultrasound Equipment, Tequesta, FL. Systems were evaluated using marbling scores and percentage ether extractable fat of the longissimus muscle. Before statistical analyses, system predictions were corrected for the respective system's average deviation between the prediction and carcass measurement. The absolute difference between system prediction and percentage ether extract (EEADIFF) or marbling score (MADIFF) converted to ether extract by regression was analyzed with a model accounting for effects of system, technician within system, animal, and animal x system. Steers with USDA marbling scores less than Small00 were assigned to a low marbling class, and all others were assigned to a second class. Data were then analyzed with a subsequent model including marbling class. For EEADIFF in the first model, system, animal, and system x animal were significant (P < .001). For MADIFF, technician within system (P < .05) and all other effects (P < .001) were significant. In the second model, system x marbling class was significant (P < .05) for EEADIFF and approached significance for MADIFF (P = .17). Least squares means for EEADIFF indicated that the systems were more precise measuring animals in the low marbling class. Finally, the CPEC and CVIS systems were the most precise for predicting intramuscular fat.

Adipose Tissue↗

PubMed2001

Predicting percentage of intramuscular fat using two types of real-time ultrasound equipment.

In the present study, 500 steers were used to develop models for predicting the percentage of intramuscular fat (PIMF) in live beef cattle. Before slaughter, steers were scanned across the 11th and 13th ribs using Aloka 500V (AL-500) and Classic Scanner 200 (CS-200) machines. Four to five images were collected per individual steer using each machine. After slaughter, a cross-sectional slice of the longissimus muscle from the 12th rib facing was used for chemical extraction to determine actual carcass percentage of intramuscular fat (CPIMF). Texture analysis software was used by two interpreters to select a region for determination of image parameters, which included Fourier, gradient, histogram, and co-occurrence parameters. Four prediction models were developed separately for each of AL-500 and CS-200 based on images captured by the respective machines. These included models developed without transformation of CPIMF (Model I), models based on logarithmic transformation of CPIMF (Model II), ridge regression procedure (Model III), and principal component regression procedure (Model IV). Model R2 and root mean square error of AL-500 Models I, II, III, and IV were 0.72, 0.84%; 0.72, 0.85%; 0.69, 0.91%; and 0.71, 0.86%; respectively. The corresponding R2 and root mean square error values of CS-200 Models I, II, III, and IV were 0.68, 0.87%; 0.70, 0.85%; 0.64, 0.94%; and 0.65, 0.91%; respectively. Initially, AL-500 and CS-200 prediction models were validated separately on an independent data set from 71 feedlot steers. The overall mean bias, standard error of prediction, and rank correlation coefficient across the four AL-500 models were 0.42%, 0.84%, and 0.88, respectively. For the four CS-200 models, the corresponding overall mean values were 0.67%, 0.81%, and 0.91, respectively. In a second validation test, only Model II of AL-500 and CS-200 was evaluated separately based on data from 24 feedlot steers. The overall mean bias, absolute difference, and standard error of prediction of AL-500 Model II were 0.71, 0.92, and 0.98%. For CS-200 Model II, the corresponding values were 0.59, 0.97, and 1.03%. Both AL-500 and CS-200 equipment can be used to accurately predict PIMF in live cattle. Further improvement in the accuracy of prediction equations could be achieved through increasing the development data set and the variation in PIMF of cattle used.

Adipose Tissue↗

PubMed1998

The adipocyte fatty acid-binding protein locus: characterization and association with intramuscular fat content in pigs.

The porcine A-FABP gene (FABP4) was isolated and sequenced to study the role of A-FABP in the differentiation of intramuscular fat (IMF) accretion in pigs. The coding sequence of the porcine A-FABP gene is highly conserved across human, mouse, and rat. Moreover, all the functionally important amino acids are conserved. This high similarity extends into the first 270 bp of the 5' upstream region. Within this region, a 56-bp nucleotide sequence was completely identical with the corresponding sequence in the mouse A-FABP gene, which contains the transcription factor binding sites for C/EBP and AP-1, and is implicated in the differentiation-dependent regulation of A-FABP. The A-FABP gene was assigned to porcine Chromosome (Chr) 4 by a porcine sequence-specific PCR on a cell hybrid panel, fully consistent with comparative mapping data with human and mouse. In the first intron of the porcine A-FABP gene, a microsatellite sequence was detected that was polymorphic for all six pig breeds tested. This genetic variation within the A-FABP gene was associated with differences in IMF content and possibly growth in a Duroc population, whereas no effect on backfat thickness and drip loss of the meat were detected. A considerable and significant contrast of approximately 1% IMF was observed between certain genotype classes. We conclude that the A-FABP locus is involved in the regulation of intramuscular fat accretion in Duroc pigs.

Adipose Tissue↗

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↗

PubMed2006

Number of intramuscular adipocytes and fatty acid binding protein-4 content are significant indicators of intramuscular fat level in crossbred Large White x Duroc pigs.

Intramuscular fat content is generally associated with improved sensory quality and better acceptability of fresh pork. However, conclusive evidence is still lacking for the biological mechanisms underlying i.m. fat content variability in pigs. The current study aimed to determine whether variations in i.m. fat content of longissimus muscle are related to i.m. adipocyte cellularity, lipid metabolism, or contractile properties of the whole muscle. To this end, crossbred (Large White x Duroc) pigs exhibiting either a high (2.82 +/- 0.38%, HF) or a low (1.15 +/- 0.14%, LF) lipid content in LM biopsies at 70 kg of BW were further studied at 107 +/- 7 kg of BW. Animals grew at the same rate, but HF pigs at slaughter presented fatter carcasses than LF pigs (P = 0.04). The differences in i.m. fat content between the 2 groups were mostly explained by variation in i.m. adipocyte number (+127% in HF compared with LF groups, P = 0.005). Less difference (+13% in HF compared with LF groups, P = 0.057) was noted in adipocyte diameter, and no significant variation was detected in whole-muscle lipogenic enzyme activities (acetyl-CoA carboxylase, P = 0.9; malic enzyme, P = 0.35; glucose-6-phosphate dehydrogenase, P = 0.75), mRNA levels of sterol-regulatory element binding protein-1 (P = 0.6), or diacylglycerol acyltransferase 1 (P = 0.6). Adipocyte fatty acid binding protein (FABP)-4 protein content in whole LM was 2-fold greater in HF pigs than in LF pigs (P = 0.05), and positive correlation coefficients were found between the FABP-4 protein level and adipocyte number (R2 = 0.47, P = 0.02) and lipid content (R2 = 0.58, P = 0.004). Conversely, there was no difference between groups relative to FABP-3 mRNA (P = 0.46) or protein (P = 0.56) levels, oxidative enzymatic activities (citrate synthase, P = 0.9; beta-hydroxyacyl-CoA dehydrogenase, P = 0.7), mitochondrial (P = 0.5) and peroxisomal (P = 0.12) oxidation rates of oleate, mRNA levels of genes involved in fatty acid oxidation (carnitine-palmitoyl-transferase 1, P = 0.98; peroxisome proliferator-activated receptor delta, P = 0.73) or energy expenditure (uncoupling protein 2, P = 0.92; uncoupling protein 3, P = 0.84), or myosin heavy-chain mRNA proportions (P > 0.49). The current study suggests that FABP-4 protein content may be a valuable marker of lipid accretion in LM and that i.m. fat content and myofiber type composition can be manipulated independently.

Adipocytes↗

PubMed2006

High-resolution physical mapping and construction of a porcine contig spanning the intramuscular fat content QTL.

We previously mapped a locus for porcine intramuscular fat content (IMF) by linkage analysis to a 17.1-cM chromosome interval on Sus scrofa chromosome 7 (SSC7) flanked by microsatellite markers SW1083 and SW581. In this study, we identified 34 microsatellite markers and 14 STSs from the 17.1-cM IMF quantitative trait loci (QTL) region corresponding to HSA14q and aligned those loci using the INRA-University of Minnesota porcine radiation hybrid (IMpRH) panel. We then constructed a 5.2-Mb porcine bacterial artificial chromosome (BAC) contig of this region that was aligned using the RH panel. Finally, the IMF QTL was fine-mapped to 12.6 cM between SJ169 and MM70 at the 0.1% chromosome-wise significance level by genotyping the previously studied F2 resource family with 17 additional microsatellites. We also demonstrated that the SJ169-MM70 interval spans approximately 3.0 Mb and contains at least 12 genes: GALC, GPR65, KCNK10, SPATA7, PTPN21, FLJ11806, EML5, TTC8, CHES1, CAP2P1, CHORDC2P and C14orf143.

Adipose Tissue↗

PubMed2003

Psoas muscle attenuation measurement with computed tomography indicates intramuscular fat accumulation in patients with the HIV-lipodystrophy syndrome.

The human immunodeficiency virus (HIV)-lipodystrophy syndrome is characterized by abnormalities of lipid metabolism, glucose homeostasis, and fat distribution. Overaccumulation of intramuscular lipid may contribute to insulin resistance in this population. We examined 63 men: HIV positive with lipodystrophy (n = 22), HIV positive without lipodystrophy (n = 20), and age- and body mass index-matched HIV-negative controls (n = 21). Single-slice computed tomography was used to determine psoas muscle attenuation and visceral fat area. Plasma free fatty acids (FFA), lipid profile, and markers of glucose homeostasis were measured. Muscle attenuation was significantly decreased in subjects with lipodystrophy [median (interquartile range), 55.0 (51.0-58.3)] compared with subjects without lipodystrophy [57.0 (55.0-59.0); P = 0.05] and HIV-negative controls [59.5 (57.3-64.8); P < 0.01]. Among HIV-infected subjects, muscle attenuation correlated significantly with FFA (r = -0.38; P = 0.02), visceral fat (r = -0.49; P = 0.002), glucose (r = -0.38; P = 0.02) and insulin (r = -0.60; P = 0.0001) response to a 75-g oral glucose tolerance test. In forward stepwise regression analysis with psoas attenuation as the dependent variable, visceral fat (P = 0.02) and FFA (P < 0.05), but neither body mass index, subcutaneous fat, nor antiretroviral use, were strong independent predictors of muscle attenuation (r2 = 0.39 for model). Muscle attenuation (P = 0.02) and visceral fat (P = 0.02), but not BMI, subcutaneous fat, FFA, or antiretroviral use, were strong independent predictors of insulin response (area under the curve) to glucose challenge (r2 = 0.47 for model). These data demonstrate that decreased psoas muscle attenuation due to intramuscular fat accumulation may contribute significantly to hyperinsulinemia and insulin resistance in HIV-lipodystrophy patients. Further studies are needed to assess the mechanisms and consequences of intramuscular lipid accumulation in HIV-infected patients.

Absorptiometry, Photon↗

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↗

PubMedDate not supplied

Lip and perioral enhancement by direct intramuscular fat autografting.

Extensive fat resorption when injected subcutaneously was proven a long time ago, as well as central fat necrosis when injected in bulk. On the other hand, direct intramuscular fat injections in the form of 1- to 2-mm threads allow good revascularization and thus proper taking of the graft with minimal resorption. Following that principle, a 2-year follow-up showed less than 20% resorption in our cases. Adipose tissue was obtained by superficial syringe liposuction from the lower abdomen or subgluteal region, or from facial subdermal collections, and then gently cleansed from the blood and local anesthetics with large quantities of a warm physiological solution. Using a strong injector with 1.5- to 2-mm blunt cannulas, the fat was injected during withdrawal in the form of very thin threads directly into the orbicular muscle to correct thin lips. To correct a bony appearance of the face, larger quantities of fat, up to 15 ml, were injected into the buccinator and zygomaticus muscles, while 5-7 ml was injected into the conjunction of the orbicularis oris, depressor anguli oris, and risorius muscles in order to elevate the corners of the mouth.

Adipose Tissue↗

PubMed2004

Intramuscular fat and glucose tolerance after spinal cord injury--a cross-sectional study.

STUDY DESIGN: Survey. OBJECTIVE: Determine intramuscular fat (IMF) in affected skeletal muscle after complete spinal cord injury using a novel analysis method and determine the correlation of IMF to plasma glucose or plasma insulin during an oral glucose tolerance test. SETTING: General community of Athens, GA, USA. METHODS: A total of 12 nonexercise-trained complete spinal cord injured (SCI) persons (10 males and two females 40+/-12 years old (mean+/-SD), range 26-71 years, and 8+/-5 years post SCI) and nine nonexercise-trained nondisabled (ND) controls 29+/-9 years old, range 23-51 years, matched for height, weight, and BMI, had T(1) magnetic resonance images of their thighs taken and underwent an oral glucose tolerance test (OGTT) after giving consent. RESULTS: Average skeletal muscle cross-sectional area (CSA) (mean+/-SD) was 58.6+/-21.6 cm(2) in spinal cord subjects and 94.1+/-32.5 cm(2) in ND subjects. Average IMF CSA was 14.5+/-6.0 cm(2) in spinal cord subjects and 4.7+/-2.5 cm(2) in nondisabled subjects, resulting in an almost four-fold difference in IMF percentage of 17.3+/-4.4% in spinal cord subjects and 4.6+/-2.6% in nondisabled subjects. The 60, 90 and 120 min plasma glucose or plasma insulin were higher in the SCI group. IMF (absolute and %) was related to the 90 or 120 min plasma glucose or plasma insulin (r(2)=0.71-0.40). CONCLUSIONS: IMF is a good predictor of plasma glucose during an OGTT and may be a contributing factor to the onset of impaired glucose tolerance and type II diabetes, especially in SCI. In addition, reports of skeletal muscle CSA should be corrected for IMF.

Adult↗

PubMed2006

Effects of intramuscular fat levels on sensory characteristics of duck breast meat.

We conducted a study to evaluate the effects of intramuscular fat levels on the sensory characteristics of duck breast meat. Combining duck genotypes (Muscovy, Pekin, and their crossbreed hinny and mule ducks) and feeding levels (overfeeding between 12 and 14 wk of age vs. ad libitum feeding) enabled us to obtain a wide range of lipid levels in breast muscle. The average values were between 2.55 and 6.40 g per 100 g of muscle. Breast muscle from overfed ducks showed higher lipid and lower water levels than breast muscle from ducks fed ad libitum. Muscle from the overfed ducks was also paler in color and exhibited greater yellowness and cooking loss values. Juiciness was judged lower and flavor more pronounced in overfed ducks. Muscovy ducks exhibited higher breast weight and lower lipid levels than the other genotypes. At the other extreme, Pekin ducks exhibited the highest lipid levels and the lowest breast weights; values for these criteria were intermediate in hinny and mule ducks. Breast muscle of Muscovy ducks was paler, less red, and more yellow than that of other genotypes. Breast muscle of Pekin ducks exhibited the lowest values for lightness, yellowness, and energy necessary to shear meat, as well as the highest cooking loss values, and was judged more tender, juicy and less stringy than that of other genotypes. In contrast, scores for breast muscle of Muscovy ducks were the lowest for tenderness, juiciness, and flavor, and the highest for stringiness. Breast muscle of hinny and mule ducks scored the highest values for redness. Hinny ducks also scored the highest values for flavor. Genotype exerted a higher effect on the sensory quality of breast muscle than did feeding levels. Finally, increasing lipid levels in breast muscle increased lightness, yellowness, cooking loss, tenderness, and flavor, with correlation coefficients of 0.49, 0.47, 0.54, 0.43, and 0.28, respectively. However, breast meat color and tenderness were mainly influenced by genotype.

Adipose Tissue↗

PubMed1998

Ultrasound image texture analysis for characterizing intramuscular fat content of live beef cattle.

The primary factors in determining beef quality grades are the amount and distribution of intramuscular fat percentage (IMFAT). Texture analysis was applied to ultrasound B-mode images from ribeye muscle of live beef cattle to predict its IMFAT. We used wavelet transform (WT) for multiresolutional texture analysis and second-order statistics using a gray-level co-occurrence matrix (GLCM) technique. Sets of WT- and GLCM-based texture features were calculated from ultrasonic images from 207 animals and linear regression methods were used for IMFAT prediction. WT-based features included energy ratios, central moments of wavelet-decomposed subimages and wavelet edge density. The regression model using WT features provided a root mean square error (RMSE) of 1.44 for prediction of IMFAT using validation images, while that of GLCM features provided an RMSE of 1.90. The prediction models using the WT features showed potential for objective quality evaluation in the live animals.

Adipose Tissue↗

PubMed2005

[Genetic parameter estimation for inosine-5-monophosphate and intramuscular fat contents and other meat quality traits in chicken muscle].

The genetic parameters for some important flavor traits like inosine-5'-monophosphate (IMP) and intramuscular fat (IMF) contents in breast meat were estimated using a MTDFREML procedure on 1063 male, 90-day-old, purebred Beijing-You meat-type chicks (BJY). The result showed that the heritability of IMP and IMF contents in BJY breast meat was moderate or low (h2=0.23, 0.10), whereas these parameters were higher for abdominal fat weight (AFW), breast meat yield (BMY), ratio of BMY to carcass weight (BMR), leg muscle yield (LMY), body weight (BW), comb weight(CW) and comb weight percentage (CWB) (h2=0.56-0.79). The heritability of abdominal fat percentage (AFP), leg meat yield (LMY), testicle weight (TW) and testicle weight percentage (TWP) were 0.24, 0.32, 0.39 and 0.35, respectively. IMP exhibited low phenotypic correlations with BMY, LMY and SFT and no significant phenotypic correlations with other traits. IMF, to some extent, exhibited positive phenotypic correlation with BW, AFP, SFT and FSW (rP=0.11-0.33). In terms of genetic correlation, IMP was moderately or significantly negatively correlated with BW and CWP (rA=-0.38,-0.62), and a high level of positive correlation was observed with BMY (rA=0.57). Moreover, IMF was highly correlated with BW and AFW (rA=0.75,0.66), and moderately correlated with AFP and CWP (rA=0.32, 0.40). A low level of positive correlation was observed between IMP and IMF (rA =0.27). We propose that IMP and IMF contents in chicken meat could be increased with selection through line-breeding.

Abdominal Fat↗

PubMed1980

[Determination of intramuscular fat in beef by means of extraction with chloroform-methanol].

In a comparison on samples of muscular substance from 53 fattening bulls the extraction of intramuscular fat with a chloroform-methanol mixture yielded results about 1.23% higher than those obtained with the extraction with diethyl ether. This difference results from the extraction of additional water-soluble nitrogenous compounds by the chloroform-methanol mixture. These compounds were isolated by adding water to the chloroform-methanol extract; their analysis by means of chemical and spectroscopic methods revealed, among other compounds, creatinine and threonine. The fat values obtained for the ether extract were closely correlated with those found for the chloroform-methanol extract (r = 0.925). In a variant where water was added to the chloroform-methanol extract, the correlation was less close (r = 0.925). In a variant where water was added to the chloroform-methanol extract, the correlation was less close (r = 0.660). The chloroform-methanol extraction may be used instead of the ether extraction. A regression calculated from the present data permits, if required, to convert the values thus obtained into the values yielded by the ether extraction method. Apart from its high precision, the chloroform-methanol extraction has the special advantage that it requires relatively simple safety measures and that its energy demand is low.

Animals↗

PubMed2006

Skeletal muscle atrophy and increased intramuscular fat after incomplete spinal cord injury.

STUDY DESIGN: Cross-sectional and longitudinal design. OBJECTIVES: (1) To quantify skeletal muscle cross-sectional area (CSA) after correcting for intramuscular fat (IMF) in thigh muscle groups 6 weeks after incomplete spinal cord injury (SCI), (2) to monitor the changes in muscle CSA and IMF after 3 months from the initial measurement. SETTING: Academic institution Athens, GA, USA. METHODS: Six incomplete SCI patients (28+/-4 years, 178+/-5 cm and 78+/-6 kg, mean+/-SE, C7 to L3, American Spinal Injury Association B or C) were tested at 5+/-1 weeks and 3 months after the initial measurement. T1-weighted magnetic resonance images were taken of both thighs. Six able-bodied (AB) controls were matched in age, sex, height and weight (29+/-4 years, four male and two female subjects, 179+/-5 cm and 77+/-6 kg). RESULTS: At 6 weeks post-injury, muscle CSA was 82+/-4 cm(2) in incomplete SCI and 123+/-21 cm(2) in AB controls (P=0.04). IMF CSA was 5.2+/-1.3 and 2.3+/-0.6 cm(2) in incomplete SCI and AB controls, respectively (P=0.03). Relative IMF was three-fold higher (P=0.03) in the SCI group versus AB controls (5.8+/-1.4 versus 2.0+/-0.6%). After 3 months, IMF increased 26% in the SCI group compared to the initial measurement (P=0.02). CONCLUSIONS: Skeletal muscle atrophy is associated with greater IMF accumulation in SCI group 6 weeks post-injury compared to AB controls. Moreover, IMF continues to increase over time in incomplete SCI.

Adipose Tissue↗

PubMed2005

Genetic parameter estimates of meat quality traits in Duroc pigs selected for average daily gain, longissimus muscle area, backfat thickness, and intramuscular fat content.

Using a multitrait animal model BLUP, selection was conducted over seven generations for growth rate (ADG), real-time ultrasound LM area (LMA), backfat thickness (BF), and intramuscular fat content (IMF) to develop a new line of purebred Duroc pigs with enhanced meat production and meat quality. This selection experiment examined 543 slaughtered pigs (394 barrows and 153 gilts) from the first to the seventh generation for meat quality traits. Further, electric impedance and collagen content of loin meat were measured from the fourth to sixth generation. The present study was intended to estimate genetic parameters of the correlated traits of tenderness (TEND), meat color (pork color standard: PCS; lightness = L*), drip loss (DL), cooking loss (CL), pH (PH), electric impedance (IMP), and collagen (COL) of the LM, and the genetic trends of these traits. Respective heritability estimates for IMF, TEND, DL, CL, PCS, L*, PH, IMP, and COL were 0.39, 0.45, 0.14, 0.09, 0.18, 0.16, 0.07, 0.22, and 0.23. Genetic correlations of IMF with ADG and BF were low and positive, but low and negative with LMA. Tenderness was correlated negatively with ADG (-0.44) and BF (-0.59), but positively correlated with LMA (0.32). The genetic correlation between LMA and DL was positive and high (0.64). The genetic correlations of TEND with IMF and COL were low (-0.09 and 0.26, respectively), but a moderate genetic correlation (0.43) between COL and IMF was estimated, suggesting related increases of IMF and connective tissue. Genetic correlations among meat quality traits suggested that when IMF increases, the water holding capacity improves. Genetic trends of meat quality traits showed increased IMF and lighter meat color.

Adipose Tissue↗

PubMed2000

The effect of adipocyte and heart fatty acid-binding protein genes on intramuscular fat and backfat content in Meishan crossbred pigs.

Effects of genetic variation in porcine adipocyte and heart fatty acid-binding protein genes, A-FABP and H-FABP, respectively, on intramuscular fat (IMF) content and backfat thickness (BFT) were examined in F2 crossbreds of Meishan and Western pigs. The involvement of each FABP gene in IMF accretion was studied to confirm previous results for Duroc pigs. The F2 crossbred pigs were genotyped for various markers including microsatellite sequences situated within both FABP genes. Linkage analysis assigned the A-FABP and H-FABP genes to marker intervals S0001-S0217 (20 cM) on SSC4 and Sw316-S0003 (16.6 cM) on SSC6, respectively, refining previous chromosomal assignments. Next, the role of both chromosome regions/genes on genetic variation in IMF content and BFT was studied by 1) screening SSC4 and SSC6 for QTL affecting both traits by performing a line-cross analysis and 2) estimation of the effect of individual A-FABP and H-FABP alleles on both traits. In the first analysis, suggestive and chromosome-wise significant evidence for a QTL affecting IMF was detected on SSC6. The H-FABP gene is a candidate gene for this effect because it resides within the large region containing this putative QTL. The second analysis showed a considerable but nonsignificant effect of H-FABP microsatellite alleles on IMF content. Suggestive evidence for a QTL affecting BFT was found on SSC6, but H-FABP was excluded as a candidate gene. In conclusion, present and previous results support involvement of H-FABP gene polymorphisms in IMF accretion independently from BFT in pigs. Therefore, implementation of these polymorphisms in marker-assisted selection to control IMF content independently from BFT may be considered. In contrast to previous findings for Duroc pigs, no evidence was found for an effect of the A-FABP gene on IMF or BFT in this population.

Adipocytes↗