• Journal of Life Science
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• v.25 no.4
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• pp.376-384
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• 2015

To investigate the molecular events of controlling intramuscular fat (or marbling), which is an important factor in the evaluation of beef quality, we performed cDNA microarray analyses using the longissimus dorsi muscle and back fat tissues. For this study, we constructed normalized cDNA libraries: fat tissues in native Korean cattle (displaying 1,211 specific genes), and muscle tissues in native Korean cattle (displaying 1,346 specific genes). A bovine cDNA chip was constructed with 1,680 specific genes, consisting of 760 genes from muscle tissues and 920 genes from fat tissues. The microarray analysis in this experiment showed a number of differentially expressed genes, which compared the longissimus dorsi muscle (Cy5) with back fat tissue (Cy3). Among many specific differentially expressed genes, 12-lipoxygenase (oxidizing esterified fatty acids) and prostaglandin D synthase (differentiation of fibroblasts to adipocytes) are the key candidate enzymes that should be involved in controlling the accumulation of intramuscular fat. In this study, differentially and commonly expressed genes in the muscle and fat tissues of native Korean cattle were found in large numbers, using the hybridization assay. The expression levels of the selected genes were confirmed by semi-quantitative RT-PCR, and the results were similar to those of the cDNA microarray.

• Animal Bioscience
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• v.34 no.7
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• pp.1193-1201
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• 2021

Objective: According to market demand, meat duck breeding mainly includes 2 breeding directions: lean Pekin duck (LPD) and fat Pekin duck (FPD). The aim of the present study was to compare carcass and meat quality traits between 2 strains, and to provide basic data for guidelines of processing and meat quality improvement. Methods: A total of 62 female Pekin ducks (32 LPDs and 30 FPDs) were slaughtered at the age of 42 days. The live body weight and carcass traits were measured and calculated. Physical properties of breast muscle were determined by texture analyzer and muscle fibers were measured by paraffin sections. The content of inosine monophosphate (IMP), intramuscular fat (IMF) and fatty acids composition were measured by high-performance liquid chromatography, Soxhlet extraction method and automated gas chromatography respectively. Results: The results showed that the bodyweight of LPDs was higher than that of FPDs. FPDs were significantly higher than LPDs in subcutaneous fat thickness, subcutaneous fat weight, subcutaneous fat percentage, abdominal fat percentage and abdominal fat shear force (p<0.01). LPDs were significantly higher than FPDs in breast muscle thickness, breast muscle weight, breast muscle rate and breast muscle shear force (p<0.01). The muscle fiber average area and fiber diameter of LPDs were significantly higher than those of FPDs (p<0.01). The muscle fiber density of LPDs was significantly lower than that of FPDs (p<0.01). The IMF of LPDs in the breast muscle was significantly higher than that in the FPDs (p<0.01). There was no significant difference between the 2 strains in IMP content (p>0.05). The polyunsaturated fatty acid content of LPDs was significantly higher than that of FPDs (p<0.01), and FPDs had higher saturated fatty acid and monounsaturated fatty acid levels (p<0.05). Conclusion: Long-term breeding work resulted in vast differences between the two strains Pekin ducks. This study provides a reference for differences between LPD and FPD that manifest as a result of long-term selection.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.7
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• pp.1012-1020
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• 2013

The objective of this study was to investigate the effect of dietary supplementation with thiazolidinedione (TZD) on growth performance and meat quality of finishing pigs. In Experiment 1, 80 castrated finishing pigs (Large White${\times}$Landrace, BW = 54.34 kg) were randomly assigned to 2 treatments with 5 replicates of 8 pigs each. The experimental pigs in the 2 groups were respectively fed with a diet with or without a TZD supplementation (15 mg/kg). In Experiment 2, 80 castrated finishing pigs (Large White${\times}$Landrace, BW = 71.46 kg) were divided into 2 treatments as designed in Experiment 1, moreover, carcass evaluations were performed. The results from Experiment 1 showed that TZD supplementation could significantly decreased the average daily feed intake (ADFI) (p<0.05) during 0 to 28 d, without impairing the average daily gain (ADG) (p>0.05). In Experiment 2, the ADG was significantly increased by TZD supplementation during 14 to 28 d and 0 to 28 d (p<0.05) and the feed:gain ratio (F:G) was significantly decreased by TZD supplementation during 0 to 28 d (p<0.05). Compared with the control group, TZD group had significantly higher serum triglyceride (TG) concentration at 28h and serum high-density lipoprotein (HDL) levels at 14 d (p<0.05). Moreover, there was an apparent improvement in the marbling score (p<0.10) and intramuscular fat (IMF) content (p<0.10) of the longissimus dorsi muscle in pigs treated by TZD supplementation. Real-time RT-PCR analyses demonstrated that pigs of TZD group had higher mRNA abundance of $PPAR{\gamma}$ coactivator 1 (PGC-1) (p<0.05) and fatty acid-binding protein 3 (FABP3) (p<0.05) than pigs of control group. Taken together, these results suggested that dietary TZD supplementation could improve growth performance and increase the IMF content of finishing pigs through regulating the serum parameters and genes mRNA abundance involved in fat metabolism.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.138-143
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• 2008

A study was conducted to evaluate nutritional value for twenty-one pork muscles. Ten market-weight crossbred pigs (five gilts and five barrows) were used for evaluating proximate chemical composition, cholesterol, total iron, calorie and fatty acid contents. As preliminary analysis revealed no noticeable sex effect, pooled data from both sexes were used for the final analysis. M. rectus femoris had the highest moisture content, while m. latissimus dorsi was lowest in moisture content (p<0.05). Protein content was highest for m. longissimus dorsi and lowest for m. supraspinatus (p<0.05). The tensor fasciae and latissimus dorsi muscles contained the highest intramuscular fat (p<0.05), while rectus femoris, adductor and vastus lateralis were lowest in intramuscular fat content. When simple correlations between chemical values were computed for the pooled dataset from all muscles, intramuscular fat had significant (p<0.05) negative linear relationships with moisture (r = -0.85) and protein (r = -0.51) contents. Calorie levels were not significantly affected by fat content, while rectus femoris and latissimus dorsi muscles showed lowest and highest calorie contents, respectively (p<0.05). Polyunsaturated fatty acid content was highest (p<0.05) for both m. adductor and m. rectus femoris, while it was lowest for m. longissimus dorsi. Collectively, the current study identified a large amount of variation in nutritional characteristics between pork muscles, and the data can be used for the development of muscle-specific strategies to improve eating quality of meats and meat products.

• Journal of Animal Science and Technology
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• v.44 no.5
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• pp.599-606
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• 2002

This study was carried out to determine the physico-chemical components and to examine it the consumers can tell the difference in eating quality of loins of Hanwoo with grade and sex. Loins of 36 carcasses were selected and their intramuscular fat, color, pH, water holding capacity, shear force, the amount of myoglobin and moisture content were measured. The result was that only intramuscular fat was significantly different with grades. In Pearson correlation coefficients among quality factors, moisture content increased significantly with the amount of myoglobin(0.514) and shear force(0.503) and decreased as intramuscular fat(－0.957) and water holding capacity(－0.491) increased. Also, content of intramuscular fat decreased as shear force(－0.565) increased. According to descriptive analysis, aroma and acceptability in the 2nd grade steer showed the highest score. Aroma, juiciness and tenderness may affect acceptability of cooked meat. Also, juiciness, tenderness and acceptability had a negative correlation with moisture content and the intramuscular fat did not affect tenderness directly.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.4
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• pp.591-595
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• 2002

Three hundred thirty five progeny testing steers of Korean beef cattle were evaluated ultrasonically for back fat thickness (BFT), longissimus muscle area (LMA) and intramuscular fat (IF) before slaughter. Class measurements associated with the Korean yield grade and quality grade were also obtained. Residual standard deviation between ultrasonic estimates and carcass measurements of BFT, LMA were 1.49 mm and $0.96cm^2$. The linear correlation coefficients (p<0.01) between ultrasonic estimates and carcass measurements of BFT, LMA and IF were 0.75, 0.57 and 0.67, respectively. Results for improving predictions of yield grade by four methods-the Korean yield grade index equation, fat depth alone, regression and decision tree methods were 75.4%, 79.6%, 64.3% and 81.4%, respectively. We conclude that the decision tree method can easily predict yield grade and is also useful for increasing prediction accuracy rate.

• BMB Reports
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• v.42 no.7
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• pp.433-438
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• 2009

The objective of this study was to identify proteins in the m. longissimus dorsi between early (12 months of age) and late (27 months of age) fattening stages of Hanwoo (Korean cattle) steers. Using two-dimensional electrophoresis and mass spectrometry, 8 proteins of 11 differentially expressed spots between the 12 and 27 month age groups were identified in the loin muscle. Among those that were differentially expressed, zinc finger 323 and myosin light chain were highly expressed in late-fattening stage, and two catabolic enzymes, triosephosphate isomerase (TPI) and succinate dehydrogenase (SDH) were expressed more in the early versus the late-fattening stage. In particular, the quantification of TPI and SDH by immunoblotting correlated well with fat content. Our data suggested that TPI and SDH are potential candidates as markers and their identification provides new insight into the molecular mechanisms and pathways associated with intramuscular fat contents of bovine skeletal muscle.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.10
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• pp.1473-1477
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• 2007

Four-and-a-half LIM-only protein 3 (FHL3) is a member of the LIM protein superfamily and can participate in mediating protein-protein interaction by binding one another through their LIM domains. In this study, the 5'- and 3'- cDNA ends were characterized by RACE (Rapid Amplification of the cDNA Ends) methodology in combination with in silico cloning based on the partial cDNA sequence obtained. Bioinformatics analysis showed FHL3 protein contained four LIM domains and four LIM zinc-binding domains. In silico mapping assigned this gene to the gene cluster MTF1-INPP5B-SF3A3-FHL3-CGI-94 on pig chromosome 6 where several QTL affecting intramuscular fat and eye muscle area had previously been identified. Transcription of the FHL3 gene was detected in spleen, liver, kidney, small intestine, skeletal muscle, fat and stomach, with the greatest expression in skeletal muscle. The A/G polymorphism in exon II was significantly associated with birth weight, average daily gain before weaning, drip loss rate, water holding capacity and intramuscular fat in a Landrace-derived pig population. Together, the present study provided the useful information for further studies to determine the roles of FHL3 gene in the regulation of skeletal muscle cell growth and differentiation in pigs.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.811-816
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• 2007

Adipocyte fatty acid-binding protein (A-FABP), which belongs to the FABP family, plays an essential role in long-chain fatty acid uptake and metabolic homeostasis, especially in adipose tissue. The pattern of A-FABP gene mRNA expression in different growth stages and its relation to intramuscular fat (IMF) accretion in pigs was studied. Fifteen female $Duroc{\times}Landrace{\times}Yorkshire$ pigs in five groups of three pigs each, weighing 1, 30, 50, 70 and 90 kg were used to study developmental gene mRNA expression of A-FABP in various adipose tissues by means of semi-quantitative RT-PCR. Results showed that A-FABP mRNA levels in subcutaneous and ventral adipose tissues first increased from 1 to 50 kg, then gradually declined from 50 to 90 kg. Moreover, the rank order of A-FABP mRNA levels determined in three adipose tissues was as follows: subcutaneous adipose>ventral adipose>mesenteric adipose. A-FABP mRNA expression in mesenteric adipose tissue was constant during development. In addition, a positive correlation from 1 to 50 kg BW pigs and a negative correlation from 50 to 90 kg BW between A-FABP mRNA levels in subcutaneous and ventral adipose and IMF content were found.

• Korean Journal of Agricultural Science
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• v.49 no.3
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• pp.407-420
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• 2022

Chicken dominates meat consumption because it is low in fat and high in protein and has less or no religious and cultural barriers. Recently, meat quality traits have become the focus of the poultry industry more than ever. Currently, poultry farming is focusing on meat quality to satisfy meat consumer preferences, which are mostly based on high-quality proteins and a low proportion of saturated fatty acids. Meat quality traits are polygenic traits controlled by many genes. Thus, it is difficult to improve these traits using the conventional selection method because of their low to moderate heritability. These traits include pH, colour, drop loss, tenderness, intramuscular fat (IMF), water-holding capacity, flavour, and many others. Genome-wide association studies (GWAS) are an efficient genomic tool that identifies the genomic regions and potential candidate genes related to meat quality traits. Due to their impact on the economy, meat quality traits are used as selection criteria in breeding programs. Various genes and markers related to meat quality traits in chickens have been identified. In chickens, GWAS have been successfully done for intramuscular fat (IMF) content, ultimate pH (pHu) and meat and skin colour. Moreover, GWAS have identified 7, 4, 4 and 6 potential candidate genes for IMF, pHu, meat colour and skin colour, respectively. Therefore, the current review summarizes the significant genes identified by genome-wide association studies for meat quality traits in chickens.