This study was to investigate the histochemical characteristics and meat quality traits among commercial Jeju black pigs (JBP), native Jeju black pig×Duroc (JD) and Jeju Landrace×Yorkshire×Duroc (JLYD). A total of 188 pigs were evaluated. JD contained a significantly lower mean area percentage of type IIb fibers than those of other breeds (P < 0.05). The muscle pH45min and pH24h were significantly higher in JD. Drip loss and color parameters were signficantly different between the breeds (P < 0.001). JD showed the highest muscle pH and lowest drip loss and L* values than the other breeds. These results imply that the longissimus dorsi muscle of Jeju black pig×Duroc pig is better meat quality than that of other breeds. Based on these results, we conclude that muscle fiber composition can explain in parts the variation of meat quality across and within breeds.

The current study was designed to estimate the pork quality traits using metabolites from exsanguination blood and postmortem muscle simultaneously under the Korean standard pre- and post-slaughter conditions. A total of 111 Yorkshire (pure breed and castrated male) pigs were evaluated under the Korean standard conditions. Measurements were taken of the levels of blood glucose and lactate at exsanguination, and muscle glycogen and lactate content at 45 min and 24 h postmortem. Certain pork quality traits were also evaluated. Correlation analysis and multiple regression analysis including stepwise regression were performed. Exsanguination blood glucose and lactate levels were positively correlated with each other, negatively related to postmortem muscle glycogen content and positively associated with postmortem muscle lactate content. A rapid and extended postmortem glycolysis was associated with high levels of blood glucose and lactate, with high muscle lactate content, and with low muscle glycogen content during postmortem. In addition, these were also correlated with paler meat color and reduced water holding capacity. The results of multiple regression analyses also showed that metabolites in exsanguination blood and postmortem muscle explained variations in pork quality traits. Especially, levels of blood glucose and lactate and content of muscle glycogen at early postmortem were significantly associated with an elevated early glycolytic rate. Furthermore, muscle lactate content at 24 h postmortem alone accounted for a considerable portion of the variation in pork quality traits. Based on these results, the current study confirmed that the main factor influencing pork quality traits is the ultimate lactate content in muscle via postmortem glycolysis, and that levels of blood glucose and lactate at exsanguination and contents of muscle glycogen and lactate at postmortem can explain a large portion of the variation in pork quality even under the standard slaughter conditions.

The objectives of this study were to investigate the correlations between various blood parameters compared with cortisol and lactate levels under the standard pre-slaughter procedure and handling conditions and to assess their potential as indicators of pork quality traits. Despite there being no additional pre-slaughter stress treatment, there is considerable variation in blood parameters at exsanguination. Serum cortisol and blood lactate levels, widely used indicators of stress, were positively correlated with blood glucose and electrolytes, such as calcium, potassium and sodium. Moreover, these parameters were significantly correlated with a rapid rate of early postmortem glycolysis and reduced water-holding capacity. In particular, blood lactate and glucose levels significantly differed between porcine quality classes. However, other blood parameters including electrolytes did not significantly differ between quality classes though they significantly correlated with pork quality traits. Therefore, serum cortisol, blood lactate and glucose have potential as indicators of the rate and extent of postmortem metabolism and ultimate pork quality under the standard procedure and handling conditions of pre-slaughter.

The aim of this study was to compare the growth, carcass, histochemical, and meat quality characteristics in Large White pig groups that were categorized by live weight (Heavy and Light) and type I fiber percentage (High and Low), a procedure which resulted in four groups (Heavy-High, Heavy-Low, Light-High, and Light-Low). As expected, the Heavy group showed heavier live weight (114 vs. 94.7kg, P<0.001) and larger loin eye area (53.3 vs. 47.8cm2, P<0.001), as well as, higher total number (1,223,000 vs. 1,140,000, P<0.05) and greater mean value cross-sectional area (CSA; 4031 vs. 3798μm2 P<0.05) of muscle fibers than the Light group. However, there were no significant differences in start and finish days among the groups (P>0.05). Heavier pigs harboring a higher percentage of type I fibers (HH) exhibited a similar mean CSA (3894 vs. 4101μm2) and total number (1,249,000 vs. 1,198,000) of muscle fibers, even though these pigs had a greater CSA of type I fibers (3181 vs. 2719μm2, P<0.05) and a smaller CSA of type IIB fibers (4048 vs. 4457μm2, P<0.05) compared to heavier pigs harboring a lower percentage of fiber type I (HL). Both the HL and Light-Low groups exhibited a rapid decline of muscle pH at the early postmortem period (5.90 and 5.85 vs. 6.08, P<0.05), paler surfaces (43.07 and 43.55 vs. 40.73, P<0.05), and higher degrees of fluid loss by exudation (6.26 and 6.39 vs. 4.22%, P<0.05) compared to the HH group due to their muscle fiber type composition. Thus, the HH pigs showed better meat quality characteristics without significant differences in growth and carcass performance compared to the HL pigs. Therefore, selection for increased live weight at the same age and muscle fiber characteristics, especially the increased type I fiber CSA and proportion, is one of the relevant indicators to improve and control meat quality without reducing the growth and carcass performance.

Variations of fresh meat quality exist because the quality traits are affected by various intrinsic and extrinsic factors. Because the meat quality is basically dependent on muscle fiber characteristics, numerous studies have reported the relationship between quality traits and fiber characteristics. Despite intensive research, the relationship is yet to be fully established, however, the present knowledge suggests several potential ways to manipulate muscle fiber characteristics to improve meat quality. The present paper reviews the definition of fresh meat quality, meat quality traits and variations of meat quality. Also, this review presents recent knowledge underlying the relationship between fresh meat quality traits and muscle fiber characteristics. Finally, the present work proposes several potential factors including breed, genotype, sex, hormone, growth performance, diet, muscle location, exercise and ambient temperature that can be used to manipulate muscle fiber characteristics and subsequently meat quality in animals.

通过比较各品种猪的猪肉质量、肌纤维以及食用品质的相关参数，确定不同食用品质是否与其猪肉质量和肌纤维的特点具有相关性。结果表明，虽然不同品种之间的胴体和猪肉品质存在显著差异，但所有的参数均在正常的质量等级之内。在食用品质上，柏克夏猪的猪肉嫩度和风味比长白猪和约克夏猪要好。

Three single nucleotide polymorphisms (SNPs) in the porcine MYOD1 gene were used for association analysis and haplotype construction to evaluate the effects of their substitution. Four hundred and three pigs of Yorkshire and Berkshire breeds were used. The mRNA expression levels of MYOD1 were examined. The g.489C>T and g.1264C>A SNPs were significantly associated with several muscle fiber characteristics, the loin eye area, and lightness. Particularly, animals having hetero-genotypes of both sites showed good performance both in lean meat production and meat quality traits. The results of haplotype substitution were similar to the associations of individual SNPs. Moreover, the 2 SNPs had significant effects on mRNA expression. Therefore, the g.489C>T and g.1264C>A SNPs in MYOD1 may be meaningful DNA markers that can be used for improving important porcine economic traits.

The purpose of this study was to determine the structure of the porcine PPARGC1A 5′ upstream region, and to find suitable molecular markers for improved meat quality and good lean meat production. Ten DNA polymorphisms, including 7 SNPs, 2 microsatellites, and 1 insertion or deletion were newly found in the 5′ upstream region of PPARGC1A. Three SNPs that had restriction enzyme site were evaluated for associations with muscle fiber characteristics and production traits. Two hundred fifty-two pigs (Yorkshire and Landrace) were used in this analysis. The c.-2894G>A genotypes was significantly associated with muscle fiber characteristics, including the number of fiber type I and IIb composition (P < 0.05), mean cross-sectional area of fibers (P < 0.01), and fiber number per unit area (P < 0.05). The animals with the GG genotype had a higher percentage of type I fibers and a lower percentage of type IIb fibers with better meat quality [higher pH value (P < 0.05) and lower drip loss (P < 0.05)] and lean meat production [larger loin eye area (P < 0.05)]. Moreover, the mRNA expression levels of PPARGC1A among genotypes were significantly different with the highest level of GG genotype. The c.-2885G>T and c.-1402A>T sites showed similar results that had significant effects on the mean cross-sectional area (CSA; P < 0.05), fiber number per unit area (P < 0.05) and loin eye area (P < 0.01). Therefore, we suggest that the c.-2894G>A polymorphism in the 5′ upstream region of the porcine PPARGC1A gene can be used as a meaningful molecular marker for simultaneous improvement of lean meat production and quality traits.

The purpose of this study was to compare parameters associated with pork quality, muscle fiber, and eating quality among various breeds, and to examine if differences in eating quality were associated to pork quality and muscle fiber characteristics. For carcass and pork quality, although there were significant differences among breeds, the values of parameters in all pigs were assigned a normal quality class, a likely outcome of the similarity in the area percentage of type I and IIB fibers. For eating quality, pork loins from Berkshire pigs were more tender and full of pork flavor than Landrace and Yorkshire pigs. Except juiciness and mouth coating, over 20% of the variability in the eating quality parameters can be explained by pork quality traits and muscle fiber characteristics using multiple regression analysis. Furthermore, differences in muscle pH(24h), cooking loss, shear force, and NPPC marbling score could explain a large proportion of variation in eating quality parameters associated with the texture of pork.

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 (LandracexYorkshirexDuroc) 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

We had achieved the accelerated life test for and the accelerating factor and activation energy based on the results obtained for the LED PKG. In this results, We had evaluated failure rate for LED lighting array and made reference to Mil-HDBK-217F for basic standard.

Although numerous studies have reported the relationships among muscle fiber characteristics, lean meat content and meat quality, controversial perspectives still remain. Conventional histochemical classifications may be involved in a high level of error, subjectivity and it could not clearly explain variety of myofibrillar protein isoforms. Therefore, more information is needed on how different factors, such as species, breeds, gender, nutrient conditions, physiological state of animals, and environment factors, affect ultimate meat quality in order to evaluate these uncertainness. Unfortunately, there is little information that completely covers with relationship among the muscle fiber types, myofibrillar proteins and enzymatic proteolysis. In addition to the perspective of postmortem metabolism, protein quality control in skeletal muscle and proteolytic degradation of muscle proteins during postmortem period could help to clarify this relationship. Therefore, the present review will focus on muscle fiber types, typing methods, muscle proteins and meat quality, and will summarize aspects of enzymatic view of proteasome.

In high-field magnetic resonance imaging (MRI) system, the signal-to-noise ratio of MR signal is so high that the receiver frequently cannot cover the full dynamic range of the MR signal. Although this problem can be overcome by using a compander (compressor and expander) composed of logarithmic amplifiers and a ROM table to retrieve the nonlinearity of the logarithmic amplifiers or by simply increasing the number of bits of analog-to-digital converter, the methods can be costly and complex or even impossible for most commercial systems. In addition, the spectrometer has to be specifically designed to operate in those modes. In this article, we developed a simple dynamic range improvement method using a receiver with optimized variable gain control in which function can be implemented without any hardware modification to the spectrometer, if the spectrometer can do gain control during a scan. Simulations as well as experiments for the brain and resolution phantom have been performed, and the results demonstrate the utility of the proposed method. © 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part A 36A: 243–254, 2010.

The objective of this study was to determine the relationships between glycolytic enzyme activities and metabolite contents measured at 45 min postmortem in porcine longissimus dorsi muscle, and also investigated the influence of the glycolytic traits on meat quality. The activities of lactate dehydrogenase (LDH) and pyruvate kinase (PK) were correlated with ATP content, and LDH activity was positively correlated with lactate content and glycolytic potential. The metabolites influenced the glycolytic rate and also affected meat quality traits such as lightness and drip loss. On the other hand, the glycolytic enzymes had limited effects on the meat quality traits, although both LDH and PK activity were correlated with muscle pH measured at 45 min postmortem. Introduction The activities of glycolytic enzymes, including lactate dehydrogenase (LDH) and pyruvate kinase (PK), are useful indicators for examining variations in metabolic traits during the early postmortem period (Gil et al., 2003). However, there is still no clear understanding of how glycolytic enzyme activity, muscle fiber characteristics, glycolytic rate, and meat quality traits are related (Allison et al., 2003; Larzul et al., 1997). Therefore, the aim of this study was to increase our knowledge on the relationships between postmortem glycolytic traits, including glycolytic enzyme activities and metabolite contents, and meat quality measurements. Materials and methods A total of 96 crossbred (Landrace × Yorkshire × Duroc) pigs were used in this study. The treatment conditions for the animals were the same both before and after slaughter. At 45 min postmortem, muscle samples were collected from the longissimus dorsi muscles at the 8th thoracic vertebra, and were analyzed for glycolytic enzymes, metabolite contents, and glycolytic rate. The LDH and PK activities of the samples were determined via procedures described by Gil et al. (2003) and Scope (1977), respectively. Metabolite content, ATP, glucose, glucose-6-phosphate (G6P), lactate, and glycolytic potential (GP) were determined according to previously reported methods (Choi et al., 2007). The glycolytic rates of the samples, including muscle pH and R-value, were evaluated at 45 min postmortem. After 24 h of chilling, the pork loins were collected to evaluate meat quality traits, including lightness, drip loss, filter-paper fluid uptake, cooking loss, and Warner-Bratzler Shear force (WBS) (Choi et al., 2007). Finally, Pearson partial correlation coefficients (SAS Institute, 2001) were evaluated to determine the relationships existing between the glycolytic traits and the meat quality measurements. Results and discussion Table 1 shows the correlation coefficients between the glycolytic enzymes and metabolites at the early postmortem period. LDH activity was positively correlated with PK activity (r = .29), lactate content (r = .38), and GP (r = .28), and was negatively correlated with ATP content (r = -.24). While PK activity was negatively correlated with ATP (r = -.24) and G6P (r = -.40) contents. The activities of LDH and PK were significantly correlated with muscle pH (r = -.33 and -.23, respectively) at 45 min postmortem (Table 2). The metabolite contents, especially ATP and lactate, were significantly correlated with the glycolytic rate during the early postmortem period. ATP content showed a positive correlation with muscle pH45 min (r = .57) and a negative correlation with the R-value (r = -.79); however, lactate content and GP showed opposite tendencies. G6P content was negatively correlated with

This study examined the relation between glycogen, lactate content and muscle fiber type composition, and evaluated their influence on postmortem glycolytic rate and meat quality. Muscle samples were classified based on their glycogen and lactate content at 45min postmortem. Muscles with low glycogen and high lactate levels showed low muscle pH(45min) and high R-values. However, muscles with low glycogen and lactate levels showed normal rates of postmortem glycolysis and normal meat quality. On the other hand, muscles with high glycogen and lactate content showed rapid postmortem glycolysis, paler surface color, higher drip loss, and higher extents of protein denaturation than muscles with high glycogen and low lactate content. These results may be partially explained by muscle fiber type composition. Muscles with low glycogen and lactate content at early postmortem are composed of significantly higher fiber type I and lower fiber type IIB as compared to muscles with high glycogen and lactate content.

The objective of this study was to investigate the effects of dehairing methods and sex on various traits of pork quality, as well as on tissue levels of the boar taint compounds androsterione and skatole. At the early postmortem period. dehided pigs showed higher muscle pH levels (p<0.05), lower temperatures (p<0.05) and lower drip loss (p<0.001) than scalded pigs. Thus, the dehairing method can affect the early postmortem glycolytic rate and water-holding capacity. Moreover, the differences in meat quality traits between the genders were small, and not considered to have practical importance. The scalding method had only a limited effect on the androsterione content. On the other hand, the scalded entire males exhibited a lower content of skatole than the dehided entire males (p<0.01). These results appear to indicate that the heating treatment from the scalding process influenced the reduction of skatole content for the scalded entire males.

This study addressed the influence of the content of myosin heavy- (MHC) and light chain (MLC) isoforms on early postmortem glycolytic rate and meat quality traits in the porcine longissimus muscle. The fast-glycolysing group showed lower contents of MHC slow and MLC 1s isoforms (P<0.05), and higher MHC fast isoform contents than the normal-glycolysing group (P<0.05). The MHC fast/slow ratio was correlated with lactate content (r=0.41) and early postmortem muscle pH (r=-0.51), and the content of the MLC 1s isoform was negatively correlated with lactate content and glycolytic potential (r=-0.38 and -0.36, respectively). Hence, both the MHC and MLC isoforms did influence metabolite contents, thus also affecting glycolytic rate, and suggested that the myosin isoforms, in particular the MHC isoforms, might also have some bearing on the extent of protein denaturation and pork quality during the early postmortem period.

ABSTRACT The circulating growth factors, interleukin, cortisol and glycolytic enzyme activities were measured at 7 days before slaughter, and the muscle histochemical characteristics were measured using longissimus dorsi muscle at 45 min postmortem. The total fiber number tended to negatively relate to the concentrations of insulin‐like growth factor (IGF) and transforming growth factor‐β (TGF‐β). The percentage of type I muscle fiber was negatively related to serum IGF‐I concentration, and positively related to serum epidermal growth factor and TGF‐β. Circulating growth factors, interleukin and cortisol were poorly correlated with muscle fiber characteristics and meat quality. These results suggest that endocrine factors measured in antemortem serum may not be appropriate parameters for the prediction of muscle fiber characteristics. PRACTICAL APPLICATIONSSelection for lean growth appears to have adversely affected various aspects of pork quality. A higher frequency of pale, soft and exudative meat is often associated with aggressive muscling in pigs. Research on the relationships between muscle intrinsic factors and phenotypic expression in skeletal muscle is important for improving our understanding of the variation of meat quality. This research suggests that endocrine factors measured at 7 days before slaughter may not be appropriate parameters for the prediction of muscle histologic characteristics.

This study examined the effects of vacuum packaging and modified atmosphere packaging (MAP) on the meat quality of alpha-tocopherol supplemented broiler chicks after prolonged refrigeration. The supplemented alpha-tocopherol levels had no effect on the body weight and feed efficiency. The dietary treatments and packaging methods had no significant effects on the level of microbial growth, lightness, and the metmyoglobin content. The vacuum packaging showed the highest level of purge loss. The broilers supplemented with either 200 or 400 IU of alpha-tocopherol had a lower level of malondialdehyde than the control group. The vacuum packaged meats from chicks fed the control diet showed the highest levels of lipid oxidation. The lipid oxidative stability was most improved in modified atmosphere (20% CO2 + 80% N-2) packaged breast meat from the broilers supplemented with either 200 or 400 IU of alpha-tocopheryl acetate.