• Asian-Australasian Journal of Animal Sciences
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• v.27 no.12
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• pp.1763-1772
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• 2014

The objective of this study was to assess the effects of constant high ambient temperatures on meat quality, antioxidant capacity, and carnosine expression in longissimus dorsi muscle of finishing pigs. Castrated 24 male DLY (crossbreeds between Landrace${\times}$Yorkshire sows and Duroc boars) pigs were allocated to one of three treatments: constant ambient temperature at $22^{\circ}C$ and ad libitum feeding (CON, n = 8); constant high ambient temperature at $30^{\circ}C$ and ad libitum feeding (H30, n = 8); and constant ambient temperature at $22^{\circ}C$ and pair-fed with H30 (PF, n = 8). Meat quality, malondialdehyde (MDA) content, antioxidant capacity, carnosine content, and carnosine synthetase (CARNS1) mRNA expression in longissimus dorsi muscle were measured after three weeks. The results revealed that H30 had lower $pH_{24h}$, redness at 45 min, and yellowness at 24 h post-mortem (p<0.05), and higher drip loss at 48 h and lightness at 24 h post-mortem (p<0.01). Constant heat stress disrupted the pro-oxidant/antioxidant balance in longissimus dorsi muscle with higher MDA content (p<0.01) and lower antioxidant capacity (p<0.01). Carnosine content and CARNS1 mRNA expression in longissimus dorsi muscle of H30 pigs were significantly decreased (p<0.01) after three weeks at $30^{\circ}C$. In conclusion, constant high ambient temperatures affect meat quality and antioxidant capacity negatively, and the reduction of muscle carnosine content is one of the probable reasons.

• Korean Journal of Veterinary Research
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• v.52 no.4
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• pp.281-283
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• 2012

An 8-year-old female, German Shepherd dog was presented with history of dyspnea and seizure. One Year Previously a lumpectomy had been performed for surgical resection of mammary mass. In serum chemistry, severe hypoglycemia and elevation of aspartate aminitransferase and creatine kinase were shown. In thoracic radiography, there were variable sized nodules in the overall lung field. On computed tomography examination, the mass was shown in left longissimus lumborum muscle. Histopathological examination revealed adenocarcinoma derived from the mammary gland. Muscular metastasis of mammary gland tumor is uncommon. This is a rare observation and could easily be overlooked or misinterpreted.

• Journal of Animal Science and Technology
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• v.63 no.1
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• pp.160-169
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• 2021

Boiled feed is obtained by mixing and boiling agricultural by-products such as rice straw, rice bran, and bean curd with grains. The study explored the change in fatty acid, free amino acid, nucleotide, mineral, cholesterol, myoglobin and collagen of longissimus dorsi muscle in Hanwoo steers fed with boiled feed. Forty steers, 20 heads per group, were divided into two groups: a control group and a boiled feed group. The steers were raised for 10 months. The boiled feed group was enriched with palmitoleic acid, oleic acid, arachidonic acid and unsaturated fatty acids compared with the control group. There were no significant differences in amino acid and nucleic acid composition between the two groups. The boiled feed group contained higher levels of iron and manganese in the boiled feed group compared with the control group. The total cholesterol level was significantly increased, whereas calorie levels, myoglobin and collagen composition showed no differences. As the supply of boiled feed increases the content of fatty acids, unsaturated fatty acids and minerals related to flavor, it should be a feed that leads to the production of high-quality beef.

• Food Science of Animal Resources
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• v.37 no.5
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• pp.780-786
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• 2017

The objective of this study was to investigate the relationship between muscle fiber characteristics, intramuscular fat (IMF) content, and fatty acids composition in longissimus lumborum (LL) muscle from Hanwoo steers. The LL muscles were obtained from four quality grades (QG) carcasses and subjected to histochemical analysis. There were significant (p<0.05) differences in fiber number percentage (FNP) and fiber area percentage (FAP) of muscle fiber types among muscles from four QGs. Both FNP and FAP of type I increased while those of type IIB decreased with increasing QG from QG 2 to QG $1^{{+}{+}}$ (p<0.05). Also, with increasing QG, the saturated fatty acid (SFA) proportion decreased while monounsaturated fatty acid (MUFA) increased significantly (p<0.05). IMF content was positively correlated with both FNP and FAP of type I, but negatively correlated with those of type IIB. The proportions of SFA and MUFA were significantly (p<0.001) correlated with both type I and IIB composition. These results implied that muscle fiber type composition is an important factor influencing fatty acid composition in LL muscle of Hanwoo steer.

• Food Science of Animal Resources
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• v.39 no.2
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• pp.197-208
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• 2019

The aim of this study was to investigate the relation of sensory quality traits of cooked beef to fresh meat quality and histochemical characteristics, especially muscle bundle traits, in the longissimus thoracis muscle of Hanwoo steers. Cooking loss negatively correlated with softness, initial tenderness, chewiness, rate of breakdown (RB), and amount of perceptible residue (AR) after chewing (p<0.05), and drip loss showed negative correlation with RB and AR (p<0.05). All the attributes of tenderness exhibited negative correlation with the Warner-Bratzler shear force value (p<0.05). Marbling score and the intramuscular fat (IMF) content showed positive correlation with all the organoleptic characteristics, including tenderness attributes, juiciness, and flavor (p<0.05). Regarding histochemical characteristics, muscle fiber size did not have a significant correlation with all the sensory quality traits, although the area percentage of type I fiber was related with softness, initial tenderness, and chewiness (p<0.05). On the contrary, the characteristics of muscle bundle were related to all the sensory tenderness attributes (p<0.05), and the sensory tenderness increased with smaller muscle bundle size (p<0.05). These results suggest that the IMF content and bundle characteristics can be used as indicators for explaining the variations in sensory tenderness in well-marbled beef.

• Korean Journal of Food Science and Technology
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• v.23 no.1
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• pp.6-14
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• 1991

Intramuscular lipid of longissimus dorsi muscle(white muscle), soleus muscle(red muscle) and cardiac muscle were autooxidized at $37^{\circ}C$ for 20 days, and the rancidity development and the effect of various factors on rancidity development were compared. Although the myoglobin content of red muscle was about 5 times as high as that of white muscle, the degree of autooxidation occurred in intramuscular lipid did not differ between red muscle and white muscle, when they had the same lipid content. Accordingly, it was suggested that the susceptibility of muscle tissues to lipid oxidation depends mainly on the lipid content of muscle tissue, regardless of muscle types. Lipid oxidation was not a major quality deterioration for dried-pork product, when it contained adequate amount of sodium nitrite and was air-tight vacuum-packed.

• BMB Reports
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• v.45 no.2
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• pp.102-107
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• 2012

The aim of this study was to investigate protein profiles related to the induction of adipogenesis within the bovine longissimus dorsi muscle (BLDM) by proteomic analysis. We analyzed BLDM proteins at different growth stages to clarify the physiological mechanisms of marbled muscle development in 20 head of Korean native cattle (11 month: 10 head, 17 month: 10 head). BLDM proteins were analyzed by two-dimensional electrophoresis and image analysis. Villin 2 was specifically identified by mass spectrometry and a protein search engine. Villin 2 protein expression in BLDM decreased during the fat development stage in test steers. In a Western blot cell culture study of spontaneously immortal bovine muscle fibroblasts, the abundance of Villin 2 was shown to be down-regulated during differentiation into muscle. In 3T3-L1 mouse embryonic fibroblasts, Villin 2 was decreased during differentiation into adipocytes. The results suggest that Villin 2 may be related to the induction of transdifferentiation and adipogenesis in bovine longissimus dorsi muscle.

• Food Science of Animal Resources
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• v.37 no.3
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• pp.392-401
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• 2017

Variations in physical toughness between muscles and animals are a function of growth rate and extend of collagen type I and III. The current study was designed to investigate the ability of growth rate, collagen concentration, collagen synthesizing and degrading genes on two different fibroblast cells derived from Hanwoo m. longissimus dorsi (LD) and semimembranosus (SM) muscles. Fibroblast cell survival time was determined for understanding about the characteristics of proliferation rate between the two fibroblasts. We examined the collagen concentration and protein expression of collagen type I and III between the two fibroblasts. The mRNA expression of collagen synthesis and collagen degrading genes to elucidate the molecular mechanisms on toughness and tenderness through collagen production between the two fibroblast cells. From our results the growth rate, collagen content and protein expression of collagen type I and III were significantly higher in SM than LD muscle fibroblast. The mRNA expressions of collagen synthesized genes were increased whereas the collagen degrading genes were decreased in SM than LD muscle. Results from confocal microscopical investigation showed increased fluorescence of collagen type I and III appearing stronger in SM than LD muscle fibroblast. These results implied that the locomotion muscle had higher fibroblast growth rate, leads to produce more collagen, and cause tougher than positional muscle. This in vitro study mirrored that background toughness of various muscles in live animal is likely associated with fibroblast growth pattern, collagen synthesis and its gene expression.

• Journal of Animal Science and Technology
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• v.64 no.2
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• pp.330-342
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• 2022

We aimed to investigate candidate proteins related to long-term caloric restriction and feed efficiency in bovine longissimus dorsi muscle (LM). A total of 31 Korean native steers were randomly distributed to ad libitum (n = 16) or caloric restriction group (n = 15) to conduct two feeding trials for 13 mon. In the first trial (10-18 mon of age), steers were fed with 100% ad libitum (NE_g = 0.63 Mcal/kg) or caloric restriction (80% of the previous day's feed intake of ad libitum group). In the second trial (18-23 mon of age), the energy value of 100% ad libitum diet was 1.13 Mcal/kg NE_g and those in caloric restriction group diet was 0.72 Mcal/kg NE_g. At the endpoint of this experiment, in each group, 6 animals were selected with high (n = 3) or low feed efficiency (n = 3) to collect muscle tissue samples (6 animals/group). From muscle tissues of 23 mo of age, we excavated 9 and 12 differentially expressed (two-fold or more) proteins in a nutritional group and feed efficiency group using two-dimensional electrophoresis, respectively. Of these proteins, heat shock protein beta-6 was up-regulated in both the caloric restriction and the low feed efficiency group. In bovine embryonic fibroblasts, the mRNA expression of heat shock protein beta-6 increased after adipogenic differentiation, however, decreased after myogenic differentiation. Our data provide that heat shock protein beta-6 may be an adipogenic protein involved in the mechanism of caloric restriction and feed efficiency in the LM of the steer.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.4
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• pp.592-598
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• 2019

Objective: Autophagy is a bulk degradation system for intracellular proteins which contributes to skeletal muscle homeostasis, according to previous studies in humans and rodents. However, there is a lack of information on the physiological role of autophagy in the skeletal muscle of meat animals. This study was planned as a pilot study to investigate changes in expression of two major autophagy-related genes, microtubule-associated protein 1 light chain $3{\beta}$ (MAP1LC3B) and autophagy related 7 (ATG7) in fattening beef cattle, and to compare them with skeletal muscle growth. Methods: Six castrated Japanese Black cattle (initial body weight: $503{\pm}20kg$) were enrolled in this study and fattened for 7 months. Three skeletal muscles, M. longissimus, M. gluteus medius, and M. semimembranosus, were collected by needle biopsy three times during the observation period, and mRNA levels of MAP1LC3B and ATG7 were determined by quantitative reverse-transcription polymerase chain reaction. The expression levels of genes associated with the ubiquitin-proteasome system, another proteolytic mechanism, were also analyzed for comparison with autophagy-related genes. In addition, ultrasonic scanning was repeatedly performed to measure M. longissimus area as an index of muscle growth. Results: Our results showed that both MAP1LC3B and ATG7 expression increased over the observation period in all three skeletal muscles. Interestingly, the increase in expression of these two genes in M. longissimus was highly correlated with ultrasonic M. longissimus area and body weight. On the other hand, the expression of genes associated with the ubiquitin-proteasome system was unchanged during the same period. Conclusion: These findings suggest that autophagy plays an important role in the growth of skeletal muscle of fattening beef cattle and imply that autophagic activity affects meat productivity.