• Journal of Life Science
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• v.33 no.12
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• pp.987-994
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• 2023

This study examined the associations between the genotypes of the galactose mutarotase (GALM) gene and carcass traits in the Hanwoo population of Jeju Island, South Korea. The GALM genotypes were determined by the 14-bp (5'-GGTCTAATGACCAG-3') insertion/deletion (InDel) polymorphisms of the 3'-untranslated region (UTR). All three genotypes (LL, LS, and SS) were found in the Hanwoo steer population. The association analysis showed significant associations between genotypes and several carcass traits, including traits related to intramuscular fat content, such as meat quality, marbling score, and backfat thickness (p<0.05). Animals harboring the SS genotype showed not only higher levels of intramuscular fat content but also lower levels of backfat thickness than animals harboring the LL and LS genotypes. On the other hand, no significant associations were found between the GALM genotypes and carcass weight, eye muscle area, meat color, or fat color (p>0.05). Deleting the 14-bp segment in the 3'-UTR resulted in the modification of the secondary structure of RNA and appeared to affect gene expression by interfering with the binding ability of GALM mRNA with RNA-binding proteins and microRNAs. These results suggest that the 14-bp InDel polymorphism in the 3'-UTR region of the GALM gene affects cattle growth traits and carcass quality through galactose metabolism-mediated fat accumulation in muscle and backfat tissues.

• Journal of Animal Science and Technology
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• v.55 no.4
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• pp.303-314
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• 2013

Knowledge regarding lipid catabolism has been of great interest in the field of animal sciences. In the livestock industry, excess fat accretion in meat is costly to the producer and undesirable to the consumer. However, intramuscular fat (marbling) is desirable to enhance carcass and product quality. The manipulation of lipid content to meet the goals of animal production requires an understanding of the detailed mechanisms of lipid catabolism to help meticulously design nutritional, pharmacological, and physiological approaches to regulate fat accretion. The concept of a basic system of lipases and their co-regulators has been identified. The major lipases cleave triacylglycerol (TAG) stored in lipid droplets in a sequential manner. In adipose tissue, adipose triglyceride lipase (ATGL) performs the first and rate-limiting step of TAG breakdown through hydrolysis at the sn-1 position of TAG to release a non-esterified fatty acid (NEFA) and diacylglycerol (DAG). Subsequently, cleavage of DAG occurs via the rate-limiting enzyme hormone-sensitive lipase (HSL) for DAG catabolism, which is followed by monoglyceride lipase (MGL) for monoacylglycerol (MAG) hydrolysis. Recent identification of the co-activator (Comparative Gene Identification-58) and inhibitor [G(0)/G(1) Switch Gene 2] of ATGL have helped elucidate this important initial step of TAG breakdown, while also generating more questions. Additionally, the roles of these lipolysis-related enzymes in muscle, liver and skin tissue have also been found to be of great importance for the investigation of systemic lipolytic regulation.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.7
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• pp.941-946
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• 2008

Single-minded 1 gene (SIM1) is a homolog of Drosophila SIM1 gene which plays a key role in the midline cell lineage of the central nervous system and is implicated in the regulation of feeding behavior and obesity in the human and mouse. In this study, porcine SIM1 gene was firstly mapped to chromosome 1p13 using radiation hybrid (RH) mapping and two polymorphisms were detected at position 607 (A/G) in SIM1 intron7 and position 780 (C/T) in SIM1 exon8. The last substitution was genotyped in a 364 F2 animal-population and an association analysis of these genotypes was performed with growth, carcass and meat quality traits by the statistical animal model. The results showed the significant influence of the SIM1 genotype on growth (p<0.05): live weight at birth, later period of growth and average daily gain; and effects on carcass composition (p<0.05): weight of head and buck kneed foreleg, backfat depth, loin eye area, carcass leaf fat and ham fat weights; and traits related to intramuscular fat content (p<0.05).

• Animal Bioscience
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• v.36 no.5
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• pp.679-691
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• 2023

The fat deposition is an important factor affecting chicken meat quality, which is closely related to lipid metabolism of chickens. Therefore, it is important to regulate the lipid metabolism of chickens to improve the chicken meat quality. Plant extracts have special regulatory effects on animal's growth and health and have been widely used in chicken breeding. Some plant extracts have been reported to have functions of changing the fatty acid composition, reducing abdominal fat percentage, and enhancing the intramuscular fat content of chickens by improving the antioxidant capacity, regulating the expression of genes, enzymes, and signaling pathways related to lipid metabolism, modulating intestinal microbiota, affecting hormones level, and regulating DNA methylation. This paper reviewed the application and mechanism of plant extracts on regulating lipid metabolism of chickens to provide a reference for the further application of plant extracts in chicken breeding.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.6
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• pp.757-765
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• 2011

Fatty acid composition of beef intramuscular tissue is an important trait because high proportions of mono-unsaturated fatty acid are related to favorable beef flavor. In this study, we investigated the effects of genetic factors, such as stearoyl-CoA desaturase (SCD), on beef carcass traits, including fatty acid composition, in the Hanwoo. Analysis of fatty acids in Hanwoo was performed using a breed raised in Gyeonbuk province (n = 395). Compared to the homozygote, the GA, CT, and CT genotypes of exon 5 in the SCD polymorphism showed a higher content of oleic acid (p<0.05) and higher contents of mono-unsaturated fatty acid (p<0.05) and marbling scores (p<0.05) in intramuscular fat. Results of haplotype analysis showed a significant presence of unsaturated fatty acids and marbling score in the $ht1^*ht2$ and $ht2^*ht2$ groups (p<0.05). Furthermore, haplotype effects more powerful than a single gene were also observed. These ht1 and ht2 types also showed a significant difference in unsaturated fatty acids and marbling score, affecting beef flavor in the Hanwoo groups. Therefore, it can be inferred that the ht1 and ht2 types might be valuable new markers for use in improvement of Hanwoo.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.2
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• pp.257-260
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• 2003

A total of 135 F2 finishing pigs (65 barrows and 69 gilts) from resource population (Large White${\times}$Meishan) were slaughtered at about 87.8 kg BW. Contents of inosine acid (IMP) and carnine (HR) in muscle were assayed by HLPC and genetic parameters for IMP content and HR content were estimated using full sibs model. There was significant sex effect on IMP content(p<0.05), $3.561{\pm}0.077mg/g$ for gilt and $3.287{\pm}0.085mg/g$ for barrow. Heritability estimates for IMP and HR content were 0.127 and 0.357, respectively. The phenotypic correlation between IMP content and HR was 0.335, pH (A) 0.024, water lose rate (WLR) -0.069, intramuscular fat (IMF) -0.214, average marbling score (MARB) -0.143, average backfat measurements (AVBF) -0.084 and average color value (CV) -0.156, respectively. The result indicated that inosine acid content in meat might be retained or slightly improved by reducing backfat depth in pig breeding.

• Food Science of Animal Resources
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• v.34 no.2
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• pp.238-244
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• 2014

This study was conducted to compare the carcass characteristics and meat quality characteristics of Duroc breed and crossbred pigs (Landrace ${\times}$ Yorkshire ${\times}$ Duroc, LYD). Duroc and crossbred pigs did not show differences in carcass characteristics. Crossbred pigs had higher moisture and protein content than Duroc breeds. However, Duroc breeds had a higher fat content than the crossbred pigs. In meat quality characteristics, crossbred pigs showed higher values of drip loss and cooking loss over Duroc breeds, while Duroc breeds showed higher ultimate pH value compared to that of crossbred pigs. However, there were no differences in water holding capacity and shear force value. In myoglobin content, crossbred pigs had higher content compared to that in the Duroc population. In subjective evaluation and sensory characteristics, Duroc breeds showed significantly higher scores in all categories except for tenderness over the crossbred pigs. However, in storage characteristics, Duroc breeds showed reduced tendency relative to crossbred pigs. Crossbred pigs had higher unsaturated fatty acid content than Duroc breeds did. In these results, Duroc breeds showed excellent meat quality characteristics with its higher intramuscular fat content and pH value, lower drip loss and cooking loss and higher juiciness and flavor, compared to the crossbred pigs.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.8
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• pp.1297-1304
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• 2007

We conducted a series of investigations in order to elucidate role of nutritional status in regulating GLUT expression and energy metabolism in porcine muscle. Firstly, the role of mild undernutrition in regulating muscle GLUT gene expression and function was studied in growing pigs (3 wk of age) on a high (H) or low (L) food intake (H = 2L) at $35^{\circ}C$ or $26^{\circ}C$. Low food intake selectively upregulates GLUT1 and GLUT4 gene expression; mRNA levels were elevated in longissimus dorsi (L. dorsi) and rhomboideus muscles but not in diaphragm or cardiac muscles. Our next step was to determine whether dietary lysine, a major primary limiting amino acid in diets for pigs, affects muscle GLUT4 expression. Pigs of 6 wk of age were pair-fed a control or low lysine (LL) diet. The control diet contained optimal amounts of all essential amino acids, including 1.15% lysine. The LL diet was similar but contained only 0.70% lysine. GLUT4 mRNA expression was upregulated by the LL diet in L. dorsi and rhomboideus muscles, whereas that in cardiac muscle was unaffected. GLUT4 protein abundance was also higher in rhomboideus muscle of animals on the LL diet. We conducted another investigation in order to elucidate effects of the LL diet on post-GLUT4 glucose metabolism. Activity of hexokinase was unaffected by dietary lysine levels while that of citrate synthase was higher both in L. dorsi and rhomboideus muscles of pigs fed on the LL diet. Glucose 6-phosphate content was higher in L. dorsi msucle in the LL group. Glycogen content was higher both in L. dorsi and rhomboideus muscles in the LL group. Further, we determined the effects of dietary lysine levels on accumulation of intramuscular fat (IMF) in L. dorsi muscle of finishing pigs. A low lysine diet (lysine content was 0.40%) meeting approximately 70% of the requirement of lysine was given to finishing pigs for two months. IMF contents in L. dorsi of the pigs given the low lysine diet were twice higher than those of the pigs fed on a control diet (lysine content was 0.65%). Finally, we proved that a well known effect of breadcrumbs feeding to enhance IMF of finishing pigs could be attributed to shortage of amino acids in diets including breadcrumbs.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.1
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• pp.126-136
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• 2019

Objective: This study was performed to compare fat content, reducing sugar contents, sensory traits, and fatty acid (FA) and volatile compound profiles in longissimus thoracis (LT) among Korean cattle (KC), Holstein (HO), and Angus (AN) steers. Methods: Twelve LT samples (about 500 g each) of KC with an average age of $31{\pm}0.42months$, an average carcass weight of $431{\pm}12.5kg$, and a quality grade (QG) of 1+ were obtained from the joint livestock products market. Twelve LT samples of HO cattle with an average age of $24{\pm}0.54months$, an average carcass weight of $402{\pm}7.81kg$, and a QG of 2 were also obtained from the same market. Twelve LT samples of AN steers with an average age of about 20 months and a QG of choice were purchased from a beef delivery company. After slaughter, samples were kept at $4^{\circ}C$ for 42 days and prepared for immediate analysis or stored at appropriate conditions. The chemical composition, color, pH, shear force, collagen content, reducing sugars, sensory evaluation, FA composition, and volatile compound content for each LT sample were analyzed. Results: The LT of KC had the highest (p<0.05) fat content, the highest reducing sugar content, and the highest scores in the sensory evaluation (flavor, tenderness, juiciness, and overall acceptance). All the sensory traits were positively correlated (p<0.001) with intramuscular fat and reducing sugar content. Several FAs and volatile compound profiles varied among the breeds. KC LT had the highest (p<0.05) concentrations of acetaldehyde, 3-methyl butanal, and 3-hydroxy-2-butanone, and these volatile compounds were positively correlated (p<0.05) with all the sensory traits. Conclusion: Variations in fat content and reducing sugar contents and FA and volatile compound profiles may contribute to differences in the sensory quality of LT among breeds.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.8
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• pp.1105-1115
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• 2015

Fifty 3-month-old male Tan lambs (similar in body weight) were divided into 5 groups to investigate the effects of different restricted pasture grazing times and indoor supplementation on the productive performances and fatty acid composition of the intramuscular fat in growing lambs. The lambs grazed for different periods of time (12 h/d, 8 h/d, 4 h/d, 2 h/d, and 0 h) and received various amounts of supplementary feedings during the 120-day trial. Pasture dry matter intake (DMI), total DMI, average daily gains and the live body weights of the lambs were measured during the experiment. The animals were slaughtered at the end of the study, their carcass traits were measured, and their longissimus dorsi muscles were sampled to analyze the intramuscular fat (IMF) content and fatty acid profiles. The results indicated that the different durations of grazing and supplementary feedings affected the animal performances and the composition of fatty acids. Grazing for 8 h/d or 2 h/d with the corresponding supplementary concentrate resulted in lambs with higher body weights, carcass weights and IMF contents. Lambs with longer grazing times and less concentrate accumulated more healthy fatty acids such as conjugated linoleic acid and n-3 polyunsaturated fatty acid and had higher n-3/n-6 ratios. Overall, a grazing allowance of 8 h/d and the corresponding concentrate was recommended to maintain a high quantity and quality of lamb meat.