• Food Science of Animal Resources
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• v.23 no.4
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• pp.315-320
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• 2003

A total of 240 crossbred(Landrace ${\times}$ Yorkshire ${\times}$ Duroc) pigs were housed from 70 kg live weight and slaughtered at weights of 95, 105, 115 and 125 kg. The left side loins of carcass were obtained at 24 hr postmortem to measure pork quality. There were significant differences(p<0.01) in eye muscle area of pork loins between the slaughter weights of 95 and 105 kg. However, no differences were observed in pork than 105 kg of slaughter weight. Ultimate pH values were decreased with increasing slaughter weight and cooking loss was also reduced(p<0.01) at the heavier weights. Slaughter weights did not affect the shear force and intramuscular fat. However, dry matter(DM) and crude protein(CP) contents of loin were increased, and cooking loss and sarcomere length were decreased with increasing slaughter weight. The lightness(L$^{*}$) and redness(a$^{*}$) of pork loin were increased with increasing slaughter weight. Results suggested that pork quality may be improved when pig slaughter weight is increased from 95 to 125 kg.

• Biomedical Science Letters
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• v.13 no.4
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• pp.251-261
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• 2007

A myofiber of skeletal muscle is composed of myofibrils, sarcolemma (plasma membrane), and constameres, which anchor the myofibrils to the sarcolemma. Achvillin is a recently identified F-actin binding muscle protein, co-isolates with dystrophin and caveolin-3 in low-density sarcolemma of striated muscle, and colocalizes with dystrophin at costameres, the specialized adhesion sites in muscle. Archvillin also binds to nebulin and localizes at myofibrillar Z-discs, the lateral boundaries of the sarcomere in muscle. However other roles of archvillin on the dynamics of myofibrillogenesis remain to be defined. The goal of this study is, by using siRNA-mediated gene silencing technique, to investigate the effect of archvillin on the dynamics of myofibrillogenesis in cell culture of a mouse skeletal myogenic cell line (C2C12), where presumptive myoblasts withdraw from the cell cycle, fuse, undergo de novo myofibrillogenesis, and differentiate into mature myotubes. The roles of archvillin in the assembly and maintenance of myofibril and during the progression of myofibrillogenesis induced in skeletal myoblast following gene silencing in the cell culture were investigated. Fluorescence microscopy demonstrated that the distribution of archvillin was changed along the course of myofibril assembly with nebulin, vinculin and F-actin and then located at Z-lines with nebulin. Fluorescence microscopy demonstrated that knockdown of mouse archvillin expression led to an impaired assembly of new myofibrillar clusters and delayed fusion and myofibrillogenesis although the mouse archvillin siRNA did not affect those expressions of archvillin binding proteins, such as nebulin and F-actin. This result is corresponded with that of RT-PCR and western blots. When the perturbed archvillin was rescued by co-transfection with GFP or Red tagged human archvillin construct, the inhibited cell fusion and myotube formation was recovered. By using siRNA technique, archvillin was found to be involved in early stage of myofibrillogenesis. Therefore, the current data suggest the idea that archvillin plays critical roles on cell fusion and dynamic myofibril assembly.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.12
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• pp.1895-1900
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• 2007

An experiment was carried out to investigate the effects of different chilling temperature on duck breast and leg meat quality. Duck carcasses were chilled for 30 minutes in water at either $0^{\circ}C$, $10^{\circ}C$ or $20^{\circ}C$ within 20 minutes of post mortem with 6 carcasses per group. Results showed no significant effects of chilling temperature on ultimate pH, protein solubility, sarcomere length and shear force value for duck breast or leg meat (p>0.05). Leg meat had higher ultimate pH, redness and shear force value, lower cooking loss, lightness, yellowness and protein solubility values than breast meat. The interaction of meat type and chilling temperature on cooking loss was significant (p<0.05). The effect of chilling temperature on cooking loss was more severe in leg meat than breast meat and $20^{\circ}C$ chilling resulted in significantly higher cooking losses than the other chilling temperatures. Results of this experiment revealed that duck carcass can be chilled at $10^{\circ}C$ without any harmful effect on meat quality including toughness of meat.

• Journal of Animal Science and Technology
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• v.65 no.1
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• pp.160-174
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• 2023

The purpose of this study was to compare marbling score, meat quality, juiciness, sarcomere length, and skeletal muscle satellite cell (SMSC) growth and related gene expression between Woori black pig (WB) and the Landrace, Yorkshire, and Duroc (LYD) crossbreed at different body weights (b.w.). WB was developed to improve meat quality and growth efficiency by crossbreeding Duroc with Korean native black pig. A total of 24 pigs were sacrificed when their b.w. reached about 50, 75, 100, and 120 kg. SMSC were isolated from the femoris muscles, and muscle and adipose tissues were sampled from the middle and the subcutaneous part of the femoris of hind legs, respectively. Expression levels of genes including Myoblast determination protein 1 (MyoD), Paired box gene 3 (Pax3), Myosin heavy chain (MyHC), and Myogenin, which are responsible for the growth and development of SMSC, were higher in LYD than the WB. Muscle growth inhibitor myostatin (MSTN), however, was expressed more in WB compared to LYD (p < 0.01). Numbers of SMSC extracted from femoris muscle of LYD at 50, 75, 100, and 120 kg b.w. were 8.5 ± 0.223, 8.6 ± 0.245, 7.2 ± 0.249, and 10.9 ± 0.795, and those from WB were 6.2 ± 0.32, 6.2 ± 0.374, 5.3 ± 0.423, and 17.1 ± 0.315, respectively. Expression of adipogenic genes in adipose tissue including CCAAT/enhancer-binding protein (CEBP)-β, peroxisome proliferator activated receptor (PPAR)-γ, and fatty acid synthase (FASN), were greater in WB when compared with LYD (p < 0.01). Results from the current study suggest that different muscle cell numbers between 2 different breeds might be affected by related gene expression and this warrants further investigation on other growth factors regulating animal growth and development.

• Food Science of Animal Resources
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• v.26 no.1
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• pp.43-48
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• 2006

To investigate the effect of boning time and storage temperature on meat quality of duck breast, a total of thirty duck breasts were designed in frozen-thawed, chilled-storage, and cold-boning samples. No significant differences were found among pH of all samples. However, cold-boning samples showed significantly (p<0.05) lower cooking loss than the other samples. Frozen-thawed samples showed significantly (p<0.05) higher lightness ($L^*$) and yellowness($b^*$), shorter sarcomere length and higher shear force values compared to the other samples. The result speculated that muscle shortening was affected by lower temperature (frozen) hence tenderness was decreased. Sarcoplasmic protein solubility showed no significant differences among samples, whereas cold-boning samples showed significantly (p<0.05) higher myofibrillar and total protein solubility than the other samples. The result of sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) patterns, chilled-storage and cold-boning samples showed degradation at high molecular protein (nebulin), which was not observed in frozen-thawed samples. Therefore, this data suggested that muscle shortening, tenderness and protein degradation are not affected by boning time rather affected by rapid change of temperature in frozen-thawed samples.

• The Korean Journal of Zoology
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• v.35 no.2
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• pp.149-160
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• 1992

Using the protein A-gold complex, the mvoabrillogenesis and actin localization of cultured myoblast were invastisated. In the superstructural changes of mvogenic cell during differentiation, pectoral myoblasts contained large nucleus and numerous ribosomes but no myofibrils during the first 24 hr of cultures. Mvoblast initiated to differentiate at 3-day of culture contained the primitive myofibrillar structure. At 96 hr of culture, the mvofibrillar structure showed reletively discernable Z band but pools defined A, H and M bands. The feature of sarcomeric structure showed more defined form at cultur 5 day. In the aspect of actin localization, actin wvas diffusely detected throughout the cytoplasm of myogenic cell and nucleus during the proliferating stage. At 72 hr of culture, with the appearantc oi primitive mvofibrils, gold particles were observed in surrounding of myofibrils but still presented in overall of cytoplasm, especially in the surface and lumen of endoplasmic reticulum. With the gradual increase of culture time, local distribution of actin was readily detected within cytoplasm. In the 5-day specimen of cultures, gold particles precisely indicate the sites of actin localifation within the sarcomere. These results indicate the time of onset of myofibrill appearance and the biosynthetic and incorporation pathway of actin molecules into sarcomeric structure during myofibrillogenesis. Thus, in the present study, the first mvoabrillar structure was detected at culture 3 day, and the initiation of assembly into a typical sarcmeric structure was observed at culture 5 day. It seems, however, that the course of events on myofibrillogenesis of cultured myoblasts can be changed with great dependence of culture conditions including the number and groluth rate of mononucleated mvoblasts after seeding although the fundamental process shows identical appearances.

• Food Science of Animal Resources
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• v.23 no.2
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• pp.115-121
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• 2003

The pork quality was determined with following treatments. The meat samples were obtained from pigs which had been fed finishing pig diets containing 5% beef tallow(Control), 3% beef tallow and 2% perillar seed oil(T1), 250 ppm vitamin E(a-tocopheryl acetate) in T1(T2), 3% beef tallow and 2% squid viscera oil(T3), 250 ppm vitamin E in T3(T4), 3% beef tallow and 2% CLA(Conjugated linoleic acid, T5). T1 had the lowest sarcomere length, salt solubility and total protein contents among the treatments. Salt solubility and total protein content of T2 and T4 which had been fed diets containing Vit. E were higher than those of T1 and T3 which had not been fed diets without Vit. E. pH and water holding capacity(WHC) values of control were higher than those of T1, T3 and T5, while WHC of T2 and T4 was higher than those of T1, T3 and T5. The hunter L value of meat and a value of fat showed higher in T5 than those in control, T, T3. The adhesiveness of T3 and the springiness of T5 in cooked meat showed higher level than other treatments.

• Food Science of Animal Resources
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• v.36 no.1
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• pp.68-76
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• 2016

This study was conducted to investigate the meat quality and sensory properties of 12 major cuts from 10 Hanwoo bulls (25-32 mon of age) after they were aged at 2℃ for 0, 7, 14, and 21 d. Protein content (%) was between 19.17 and 22.50%. Intramuscular fat content ranged from 2.79 to 8.39%. The collagen content of the chuck roll, chuck tender, and short plate muscles was higher (1.97-2.04%) than that of the striploin muscles (1.48%) (p<0.05). CIE lightness (L*) values increased with an increase in aging days for tenderloin, loin, chuck roll, oyster blade, short plate, top sirloin, and eye of round muscles (p<0.05). Most muscles, except the short plate, showed no significant changes in redness CIE (a*) and yellowness (b*) color values during aging. The tenderloin, loin, and striploin showed significantly higher water holding capacity (58.60-62.06%) than that of chuck roll and short plate (53.86-57.07%) muscles (p<0.05). The Warner-Bratzler shear force values of most muscles decreased significantly as the aging period increased (p<0.05), exception the tenderloin. The chuck tender muscles showed the highest cooking loss, whereas tenderloin muscle showed the lowest (p<0.05). The tenderloin muscle had the longest sarcomere length (SL) (3.67-3.86 μm) and the bottom round muscle had the shortest SL (2.21-2.35 μm) (p<0.05). In the sensory evaluation, tenderness and overall-likeness scores of most muscles increased with increase in aging days. The tenderloin and oyster blade showed relatively higher tenderness and overall-likeness values than did the other muscles during the aging period. No significant differences were noted in juiciness and flavor-likeness scores among muscles and aging days.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.12
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• pp.1923-1932
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• 2019

Objective: We investigated visual marbling level (VML) influence on pork loin physicochemical traits, consumer palatability responses, VML liking, purchase intent, and their relationships. Methods: For each of five slaughtering dates, at 24-h postmortem, nine paired Duroc castrated male boneless Longissimus dorsi (LD) muscles were categorized into low (LM, score 1 to 2, n = 3), medium (MM, score 3 to 4, n = 3), and high (HM, score 5 to 6, n = 3) VML. Meat physicochemical quality traits and consumer responses (n = 389) on palatability and VML liking, and purchase intent were evaluated. The experiment was in randomized complete block design. Analysis of variance, Duncan's multiple mean comparisons, and correlation coefficients were determined. Results: VML correspond to crude fat (r = 0.91, p<0.01), but both were reversely related to moisture content (r = -0.75 and -0.91, p<0.01, respectively). As VML increased, ash (p<0.05) and protein (p = 0.072) decreased, pH and $b^{\star}$ increased (p<0.05), but drip, cooking (p<0.05) and thawing (p = 0.088) losses decreased. Among treatments, muscle fiber diameter, sarcomere length, total and insoluble collagen contents, $L^{\star}$, and $a^{\star}$ did not differ (p>0.05). Compared to the others, HM had lower collagen solubility percentage (p<0.05), but similar (p>0.05) Warner-Bratzler shear force (WBSF). No differences (p>0.05) were found in juiciness, overall flavor, oiliness, and overall acceptability, but HM was more tender (p<0.05) than the others. Based on VML, consumers preferred MM to HM (p<0.05), while LM was similar to MM and HM (p>0.05). Corresponding to VML preference (r = 0.45, p<0.01), consumers (83%) would (p<0.01) definitely and probably buy MM, over LM (74%), and HM (68%), respectively. Conclusion: Increasing VML in pork LD altered its chemical composition, slightly increased pH, and improved water holding capacity, thereby improving its tenderness acceptability. Marbling might reduce chewing resistance, as lower collagen solubility in HM did not impact tenderness acceptability and WBSF. While HM was rated as most tender, consumers visually preferred and would purchase MM.