• Food Science and Biotechnology
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• 제14권5호
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• pp.667-671
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• 2005

The aim of this study is to investigate the effects of the muscle mass and fiber number on post-mortem metabolic rates and pork quality. Carcass traits, muscle fiber characteristics, and type of fiber composition were evaluated using a sample of 200 cross-bred pigs. The muscle mass was divided into two groups according to carcass weight and loin-eye area measurements (heavy or light). In addition, the muscle histological characteristics were divided into two groups according to the muscle fiber density and total number of muscle fibers (high or low). All the carcass traits were significantly different in the muscle mass groups. Increasing weight significantly affected the cross-sectional area (CSA) of all fibers. The low group, which had a low muscle fiber number indicating a larger CSA of fibers, and especially the heavy-low group had the highest CSA levels of fibers. The fiber number percentage and the area percentage were significantly different in the groups categorized by fiber number. The heavy-high group indicated a normal rate of pH decline and the R-value. In addition, pigs with a heavy muscle mass and high muscle fiber number indicated normal drip loss, lightness, and protein denaturation. The present results suggest that increasing the total muscle fiber number has a beneficial effect on increasing the muscle mass without deteriorating the meat quality.

• Asian-Australasian Journal of Animal Sciences
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• 제17권3호
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• pp.428-433
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• 2004

The aim of this study was to investigate the histochemical parameters of muscle fibers, and to estimate the correlation between these histological parameters and carcass traits in pigs. A total of 230 crossbred Duroc$\times$(Yorkshire$\times$Landrace) pigs (149 gilts and 81 castrated male pigs) was evaluated. Carcass traits (carcass weight, backfat thickness, and loin eye area), muscle fiber size (crosssectional area, diameter, and perimeter), muscle fiber number (density of fibers/$mm^2$ and total number of fibers), and fiber type composition (percentages of myofibers and relative areas of each fiber type) were evaluated. Mean cross-sectional area (CSA) and type IIB fiber CSA were positively correlated to carcass weight, backfat thickness and loin eye area. Mean fiber CSA was mostly related to type IIB CSA (r=0.98) as a result of the high percentage of type IIB fibers in the longissimus muscle. Correlations between fiber diameters and perimeters were also high, and showed similar results with CSA. Mean fiber density was negatively correlated to carcass weight (r=-0.24), backfat thickness (r=-0.18) and loin eye area (r=-0.27). To the contrary, total fiber number was positively correlated with carcass weight (r=0.27) and loin eye area (r=0.53). Carcass weight and loin eyZe area were not significantly related to muscle fiber composition. For backfat thickness, there was an opposition between type IIA percentage, which was positively related and type IIB percentage, which was negatively related. Fiber type composition of type I and IIA fibers were negatively correlated to that of type IIB fibers (r=-0.67 to -0.74). In the present study, carcass weight and loin eye area were positively correlated to CSA and negatively correlated to fiber density. But, these relationships were generally low. The fiber density was strongly affected by muscle fiber size and the total fiber number was affected either by CSA of muscle fiber and loin eye area. Fiber type composition was much more related to their numerical abundance than their CSA.

• Asian-Australasian Journal of Animal Sciences
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• 제21권10호
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• pp.1529-1534
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• 2008

The aim of this study was directed at exploring the possible use of muscle fiber characteristics as new selection traits for improving both porcine lean meat production and quality. A total of 174 (114 Yorkshire, 30 Landrace, and 30 Meishan) pigs were used for this study, and lean meat production ability was estimated by backfat thickness and loin eye area. The Longissimus dorsi muscle was taken in order to measure meat quality and muscle fiber characteristics. Due to the high correlations between total muscle fiber number and most of the performance traits, all pigs were classified into three groups (low, intermediate, or high) by total muscle fiber number using cluster analysis. The high group had the highest loin eye area (p<0.001). The meat quality traits were within normal ranges as reddish pink, firm, and nonexudative (RFN) pork, but the groups classified as intermediate and high had relatively large drip loss percentages (p<0.05), produced more than twice the amount of pale, soft, and exudative (PSE) pork as compared to the low group. The group with a high total muscle fiber number was further classified, based on type 2b fiber percentage, into low or high groups by cluster analysis. The results showed that the low type 2b fiber group had good loin eye area (p<0.05), small drip loss (p<0.05), and did not produce PSE pork. For these reasons, a high total muscle fiber number, with a low percentage of type 2b fibers, may be suitable in selecting for improvements in both lean meat production and meat quality.

• 한국축산식품학회지
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• 제36권5호
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• pp.583-593
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• 2016

The aim of this study was to investigate the effects of morphological characteristics of porcine muscle fibers on growth performance, muscle fiber characteristics, and pork quality taken from the longissimus dorsi muscle. A total of 239 crossbred pigs (164 castrated males and 75 females) were used in this study. Experimental pigs were categorized by the total number of muscle fiber (TNF: High and Low) and cross sectional area of muscle fiber (CSAF: Large, Middle, and Small). Their combinations were classified into six groups (High-Large, HL; High-Middle, HM; High-Small, HS; Low-Large, LL; Low-Middle, LM; Low-Small, LS). The TNF and CSAF were significantly (p<0.05) correlated with growth rate and carcass productivity, while the only of the type I number had no meaningful relationships excluding the correlation with loin area (p<0.001). The proportion of type I area was positively correlated with pH_{45 min} while the proportion of type IIB area was negatively correlated with pH_{45 min} and pH_{24 h} (p<0.05). Drip loss and protein denaturation had strong relationships with the proportion of type IIB number or area. The HL group exhibited the greatest growth performance. In addition, the HL group had significantly greater values in protein solubility than the other groups. In conclusion, this study suggest that high TNF combined to large CSAF improve the ultimate lean meat productivity and assure normal meat quality simultaneously with increased both proportion of number and area of type I, type IIA muscle fibers and lowered proportion of number and area of type IIB.

• Asian-Australasian Journal of Animal Sciences
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• 제23권7호
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• pp.965-971
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• 2010

The purpose of the current study was to examine the influence of different maternal nutrition treatments during pregnancy on body weight, muscle fiber number, carcass traits, and pork quality traits of offspring. A total of 18 crossbred sows (Landrace${\times}$Yorkshire${\times}$Duroc) were randomly assigned to one of three nutritional treatment groups; control, high energy, and high protein. The control group was fed a standard diet, the high energy group was fed a diet that contained 30% increased metabolizable energy, and the high protein group was fed a diet that contained 30% increased limiting amino acids compared to the control. The sows in each group were fed equal quantities of each diet (1.9 kg/d) for the entire gestational period. A total of 36 piglets from each sow were used to evaluate changes in body weight, muscle fiber number in the longissimus dorsi muscle at birth, carcass traits, and pork quality traits. Birth weight of offspring born to sows in the high energy diet group was significantly higher compared to the high protein diet group (p<0.05). However, body weight of offspring after birth was not significantly different between the groups. Muscle fiber number for the longissimus dorsi muscle at birth was not significantly different between the groups. In addition, there were no significant differences in carcass traits or pork quality traits between offspring born to sows in the control group and those born to sows that received high energy or high protein diets during pregnancy. Based on these results, it appears that maternal nutrition treatment during pregnancy, regardless of whether it is with high energy or high protein diets, does not have a significant effect on body weight, muscle fiber number at birth, carcass traits, or pork quality traits.

• 한국축산식품학회지
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• 제39권1호
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• pp.151-161
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• 2019

The objective of this study was to investigate the correlations of marbling characteristics, including marbling score, intramuscular fat (IMF) content, and fleck traits, with meat quality traits and histochemical characteristics of the longissimus thoracis muscle from Hanwoo steers. Marbling fleck characteristics, especially area, number, and fineness (F) index, measured by computerized image analysis were strongly correlated with marbling score and IMF content (p<0.05). However, coarseness (C) index and F/C ratio were somewhat limited relationships with marbling score. In contrast, the IMF content and the number of smaller white flecks increased with increasing lightness value (p<0.05). Moreover, beef with higher marbling scores showed lower cooking loss and Warner-Bratzler shear force value compared to beef with lower marbling scores (p<0.05). Regarding the muscle bundle traits, as number of bundle increased, number of marbling flecks increased (p<0.05), although most marbling characteristics did not have significant correlation with muscle fiber or bundle characteristics.

• 한국축산식품학회지
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• 제37권6호
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• pp.873-883
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• 2017

Variations in the definition of poultry meat quality exist because the quality traits are not solely based on intrinsic and extrinsic factors but also consumers' preference. Appearance quality traits (AQT), eating quality traits (EQT), and reliance quality traits (RQT) are the major factors focused by the consumer before buying good quality of poultry meat. AQT and EQT of poultry meat are controlled by physical and biochemical characteristics of muscle fibers which can be categorized into a total number of fibers (TNF), cross-sectional area of fibers (CSAF), and fiber type composition (FTC). In poultry meat, it has been shown that muscle fiber properties play a key role in meat quality because numerous studies have reported the relationships between quality traits and fiber characteristics. Despite intensive research has been carried out to manipulate the muscle fiber to improve poultry meat quality, demand in a rapid growth of poultry muscle has correlated to the deterioration in the meat quality. The present paper reviews the definition of poultry meat quality, meat quality traits, and variations of meat quality. Also, this review presents recent knowledge underlying the relationship between poultry meat quality traits and muscle fiber characteristics.

• 한국축산식품학회지
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• 제39권6호
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• pp.988-999
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• 2019

To investigate the relationship between muscle fiber characteristics and meat quality traits by age of Korean native black goat (KNBG), four muscles (longissimus dorsi, LD; psoas major, PM; semimembranosus, SM; gluteus medius, GM) were obtained from five adult goat (AG; 18 months old) and five young goat (YG; 9 months old). PM muscle had the highest fiber number percentage (FNP) and fiber area percentage (FAP) of type I, followed by SM, GM, and LD muscles. FNP and FAP of type IIB were significantly (p<0.001) higher in AG than those in YG. YG had higher L^* values but lower b^* values than AG. The highest L^* and b^* values were observed in LD muscle (p<0.001). Age and muscle type had detrimental (p<0.001) effect on shear force and collagen content for all muscle in AG as compared to YG. YG had significantly (p<0.001) higher myofibrillar fragmentation index (MFI) than AG for all four muscles. These results suggest that muscle fiber compositions of different muscle types of KNBG depend on age, resulting in variations of meat color, MFI, collagen content, and shear force.

• 한국축산식품학회지
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• 제37권5호
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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.

• Journal of Animal Science and Technology
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• 제54권3호
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• pp.175-183
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• 2012

The present study was conducted to investigate the relationships of muscle fiber characteristics to dietary energy density [3.0(Low-E) vs. 3.2 (Med-E) Mcal DE/kg)] and slaughter weight [SW; 110, 125, and 138 kg] in finishing pigs (gilt vs. barrow) using a $2{\times}3{\times}2$ factorial treatment design. Forty-one longissimus dorsi muscle (LM) samples were analyzed histochemically, with growth performance and physicochemical data for the 41 animals and their LM out of 192 animals and 72 LM used in a previous study retrospectively included. The ADG was less (P<0.01) in the Low-E than in the Med-E group (0.93 vs. 0.73 kg) whereas lightness ($L^*$) and redness ($a^*$) of LM were greater in the Low-E group SW did not influence these variables. The diameter and perimeter of the type I (slow-oxidative), type IIA (fast oxido-glycolytic) and type IIB (fast glycolytic) fibers increased with increasing SW whereas densities of the fibers decreased. However, the number and area percentages of the fiber types were not influenced by SW or dietary energy density. The percentage and per-$mm^2$ density of type IIB fibers were negatively correlated with SW (r = -0.33 and -0.57, with P<0.05 and <0.01, respectively), whereas type I fiber number percentage was positively correlated with SW (r = 0.31; P<0.05). Marbling score was negatively correlated (P<0.05) with type I (r = -0.36) and type IIB (r = -0.39) fiber densities. The $a^*$ was correlated (P<0.01) with both type I and type IIB fiber number percentages in the opposite way (r = 0.42 and -0.47, respectively). However, $L^*$ (lightness), drip loss and $pH_{24h}$ were not correlated with the fiber number percentage or density of any fiber type. Collectively, results indicate that muscle fibers grow by hypertrophy during the late finishing period, but that fiber characteristics other than the size are not significantly influenced by dietary energy density or SW.