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1.
A total of 204 purebred Hampshire pigs were obtained from 23 breeders. These animals were the progeny of 41 sires and 123 dams. A sample of purebred Yorkshire (n = 24) pigs were also used in the study. Animals were classified by glycolytic potential determined on a live-animal longissimus muscle biopsy sample. Hampshire pigs (n = 176) with glycolytic potential greater than 185 micromol/g (x = 238.8 micromol/g; SD = 29.54) were classified as heterozygous or homozygous for the dominant RN- allele (RN-rn+ or RN-RN-, respectively), whereas cohorts (n = 28) with glycolytic potential less than 185 micromol/g (x = 141.3 micromol/g; SD = 24.48) were considered as homozygous normal (rn+rn+). All Yorkshire pigs (n = 24) had a mean glycolytic potential level of 146.1 micromol/g (SD = 20.18) and were considered as homozygous normal (rn+rn+). The Hardy-Weinberg equilibrium yielded frequencies of .630 and .370 for the dominant RN- allele and normal rn+ alleles in the Hampshire population, respectively, and genotypic frequencies of .397 (RN-RN-), .466 (RN-rn+), and .137 (rn+rn+). Hampshires with glycolytic potential > or = 185 micromol/g had significantly lower longissimus muscle ultimate pH, intramuscular fat, subjective marbling scores, and percentage of protein (P < .001) and had greater longissimus muscle percentage of moisture (P < .001), drip loss (P < .01), and cooking loss (P < .001) than rn+rn+ Hampshires and Yorkshires. These data suggest the RN- allele exists at a high frequency within the American Hampshire breed. Higher glycolytic potential levels, which accompany the allele, may cause decreased meat quality.  相似文献   

2.
The objective of this study was to determine the effects of the Halothane (N) and Rendement Napole (RN) genes on carcass and meat quality characteristics in pigs. Halothane and RN carrier (Nn/RN- rn+) Hampshire boars (n = 4) were mated to dams that were homozygous for the normal allele of both genes (NN/rn+ rn+) to produce progeny of four genotypes: 1, NN/rn+ rn+ (n = 31); 2, Nn/rn+ rn+ (n = 27); 3, NN/RN- rn+) (n = 30); and 4, Nn/RN- rn+ (n = 23). A DNA test was used to determine Halothane genotype, and longissimus glycolytic potential was used to predict the RN genotype. Pigs were reared under standard conditions to approximately 120 kg live weight and slaughtered at a commercial plant, and carcass characteristics and meat quality were evaluated. Halothane carriers (Nn/ _ _), in comparison to Halothane normal (NN/_ _) pigs, had shorter carcasses, lower longissimus ultimate pH, higher Minolta L* and b* values, and greater drip loss. Rendement Napole gene carriers (_ _/RN- rn+) had higher L* and b* values and drip and cooking loss and lower longissimus ultimate pH than homozygous recessive animals (_ _/rn+ rn+). There were Halothane x RN genotype interactions (P < 0.05) for subjective color, firmness, and marbling scores, and for shear force. Animals that were normal for both genes (NN/rn+ rn+) had the highest subjective scores for color (2.60, 1.88, 1.85, and 1.95, SE = 0.181, P < 0.05), firmness (2.53, 2.03, 2.10, and 1.89, SE = 0.182, P < 0 .05), and marbling (2.11, 1.44, 1.53, and 1.55, SE = 0.153, P < 0 .05) for genotypes 1, 2, 3, and 4, respectively, suggesting darker, firmer muscle with a higher level of marbling for this genotype. Shear force was highest for Nn/rn+ rn+ animals (3.83, 4.41, 3.79, and 3.70, respectively, SE = 0.172, P < 0.05). Gilts had less s.c. backfat thickness, greater longissimus muscle area, and lower subjective marbling scores than barrows. There was no effect (P > 0.05) of gender on other meat quality traits. This study illustrates the negative effects of the Halothane and RN genes on fresh pork quality and suggests that in combination the detrimental effects of the two genes are additive for ultimate pH, objective color, and water-holding capacity.  相似文献   

3.
The purpose of the present study was to compare Rendement Napole (RN) classification from glycolytic potential (GP) and DNA techniques, and to study the effect of the RN gene on performance, carcass, muscle quality, and sensory traits. Progeny (N = 118) from the mating of 15 purebred Hampshire sires to York x Landrace females were classified for RN gene status using the GP of the loin and polymerase chain reaction-restriction fragment length polymorphism sequence methodology. Females mated in the study (N = 32) were considered normal (rn+/rn+) based on a loin GP measurement taken on samples collected by live press biopsy. Progeny were randomly selected for harvest within a litter for each sire. Observed mean, standard deviation, and range of progeny loin GP values were 132.2, 30.7, and 70.0 to 193.0 micromol/g, respectively. The GP data were not normally distributed. Peak numbers of observations occurred between 120 and 129 micromol/g and 160 to 169 micromol/g. Pigs with a loin GP of > 150 micromol/g were classified RN-/rn+ based on the observed valley between the peak values, resulting in 37 pigs classified as RN-/rn+ and 81 pigs classified as rn+/rn+. Using DNA procedures, 81 RN-/rn+ and 37 rn+/rn+ pigs were observed. All classification errors occurred when GP values were < or = 150 micromol/g, with 30 of 44 and 14 of 44 classification errors occurring when loin GP values were between 121 and 150 micromol/g and 70 and 120 micromol/g, respectively. Gene effects, based on DNA results, were evaluated using mixed-model procedures with fixed effects of DNA genotype and gender, and random sire and litter effects. No RN genotype differences for growth rate,10th-rib backfat, or loin muscle area were observed. Loins from the RN-/rn+ pigs had significantly (P < 0.05) lower ultimate pH (0.16 units), greater GP (50.3 micromol/g), greater drip loss (0.93%), paler objective color (L*, 1.66 units), paler visual color (0.31 units), and lower firmness (0.61 units) scores. Additionally, loins from RN-/rn+ pigs had significantly (P < 0.05) lower marbling scores (0.68 units) and intramuscular fat content (0.25%) and greater cooking loss (2.51%). Cooked moisture, juiciness score, and mechanical and sensory tenderness measures did not differ between genotypes. The GP-based classification did not correctly classify RN genotype in the present study, emphasizing the importance of the direct DNA analysis for estimation of gene frequency and effects. The DNA-based genotype results clearly indicate the RN- allele has negative effects on muscle quality measures.  相似文献   

4.
Progeny (n = 70) from unrelated, DNA tested, Rendement Napole carrier (RN-/rn+) Hampshire sires, and DNA tested, Rendement Napole normal (rn+/rn+) Yorkshire dams were genotyped for the segregating RN- allele via DNA marker-assisted methodology. Six slaughter groups ensued, with littermates all being represented within the same slaughter group. Boneless pork loins were removed from right carcass sides after a 48-h chill at 2 degrees C. The anterior portions of the loins were not enhanced, whereas the posterior sections were enhanced with a solution containing 0.5% sodium chloride and 0.5% sodium tripolyphosphate to 110% of their initial weight. Carcasses of carrier pigs had less (P < 0.05) 10th rib fat depth and a greater (P < 0.01) percentage carcass lean than carcasses of normal pigs. Postmortem LM pH of carrier pigs was lower (P < 0.002) at 3, 6, 12, and 24 h, and tended to be lower (P = 0.062) at 48 h compared with that of normal animals. Samples of LM from carrier pigs had greater (P < 0.01) glycolytic potential values, drip loss percentages, and a* values, and lower pH values at fabrication than LM from normal pigs. No genotype differences (P > 0.05) were found for LM lactate, L*, or b* values. Nonenhanced semimembranosus samples from carrier pigs exhibited greater (P < 0.05) purge loss percentages and L* values, and lower (P < 0.01) pH values than samples from normal pigs. Enhanced LM samples exhibited greater (P < 0.05) drip and purge loss percentages, greater pH, and lower L* values at fabrication, regardless of Napole status. These findings suggest that the Napole gene has a positive influence on carcass leanness but detrimental effects for lean quality, which were often further compounded when meat was subjected to enhancement treatment.  相似文献   

5.
OBJECTIVE: To investigate influence of the Rendement Napole (RN-) mutation on proglycogen (PG) and macroglycogen (MG) content in skeletal muscles before and after exercise and evaluate glycogen concentrations within various muscle fiber types. ANIMALS: 5 pigs with the RN- mutation and 3 noncarrier pigs. PROCEDURE: Pigs performed 2 exercise tests on a treadmill. In the first, pigs (mean body weight, 27 kg) ran a distance of approximately 800 m. In the second, pigs (mean body weight, 63 kg) ran until fatigued. Biopsy specimens (biceps femoris muscle) for determination of PG and MG contents were obtained before and after exercise, 24 hours after the first test, and 3 hours after the second test. Histochemical analysis was performed on specimens obtained before and after the second test. RESULTS: Before exercise, PG stores did not differ markedly between groups, but MG stores were twice as high in pigs with the RN- mutation, compared with noncarrier pigs. The MG content decreased to a similar extent in both groups after exercise. Resynthesis of MG was greater in pigs with the RN- mutation than in noncarrier pigs by 3 hours after exercise. A low glycogen content after exercise was observed in many type I and type IIA fibers and in some type lIB fibers. CONCLUSIONS AND CLINICAL RELEVANCE: The RN- mutation was associated with high MG stores in skeletal muscle that did not influence exercise performance. The RN- mutation did not impair glycogenolysis during exercise but may induce faster resynthesis of MG after exercise.  相似文献   

6.
An experiment involving 32 individually housed, castrated male pigs was conducted to determine the effects of environmental temperature (12 degrees C = T12 or 28 degrees C = T28) on the performance, carcass characteristics, muscle and adipose tissue metabolism, and meat quality of pigs fed to achieve equal rates of weight gain between 8 and 92 kg live weight. The T12 pigs had less muscle (P less than .01) and more subcutaneous fat (P less than .01) in the ham than did T28 animals. Thyroids and adrenals were heavier (P less than .01) in T12 than in T28 pigs. Percentage of type I muscle fibers was higher (P less than .01) and fiber cross-sectional areas smaller (P less than .01) in semispinalis muscle (SS) of T12 pigs, whereas no effect of temperature was noticed in longissimus muscle (LD). Cold exposure induced a larger increase in oxidative metabolism in SS (+30 to 32%, P less than .001) than in LD (+14 to 17%, P less than .10) and an enhanced glycolytic metabolism in LD (P less than .05). Lipid concentration was higher in SS of T12 than in that of T28 pigs. Lipogenic enzyme activities and unsaturation of backfat were higher in T12 than in T28 pigs, whereas no effect of temperature was noticed in leaf fat. Cold treatment resulted in a faster postmortem pH decline (P less than .01), higher glycolytic potential (P less than .01), and lower ultimate pH (P less than .01) in LD. The results indicate that 12 degrees C vs 28 degrees C induced detrimental effects on growth, ham composition, and muscle and adipose tissue quality.  相似文献   

7.
Pork quality depends on various genetic and environmental factors. Despite the improvement of slaughter conditions, the PSE type is still one of the main concerns in this field. This study was conducted on nonstressed animals to evaluate the tissue characteristics of some muscles usually involved during stress compared with a reference muscle, the M. triceps brachii, which is actually not subject to stress-caused damages. Samples of M. triceps brachii, M. longissimus dorsi, M. biceps femoris, and M. semimembranosus were taken from pigs exhibiting 1 of the 3 HAL genotypes (NN, Nn, or nn) and 2 of the 3 RN genotypes (rn+rn+ or rn+RN-). Histoenzymology and immunohistochemistry were used to compare the fiber typing and capillary network in these muscles within these different stress susceptibility genotypes. In comparison with the reference muscle, M. triceps brachii, the combination of a high value of the number of type IIb fibers and a low vascular network showed a primary effect on muscles usually involved during stress. This led to the definition of a PSE index. A dramatic increase (P < 0.001) in this PSE index was systematically found in muscles usually involved in the PSE-type condition. These results show that distinctive histological characteristics were associated with the vulnerability of some muscles independently of the genotypes. Moreover, this study highlights the distinctive histological features of each genotype and is likely to suggest some interactions between them.  相似文献   

8.
The objective of this experiment was to determine the effect of diverse production systems on pig performance, muscle characteristics, and their relation to pork quality measures. Birth and rearing conditions were evaluated using 48 barrows during the fall/winter months. Pigs were farrowed in either indoor crates or outdoor huts. At weaning, indoor- and outdoor-born pigs were allotted randomly to treatments arranged in a 2 x 2 factorial design with two birth (indoor vs. outdoor) and rearing (indoor vs. outdoor) environments. Pigs housed indoors were on concrete-slatted flooring (1.2 m2/pig), and pigs housed outdoors were on an alfalfa pasture (212 m2/pig). Body weight data were collected. Muscle samples were removed within 1 h postmortem from the longissimus (LM) and semimembranosus (SM) muscles. Muscle samples were stained histochemically to identify type I, IIA, and IIB/X muscle fibers. Boneless loins were collected from the left side of each carcass and aged for 14 d. Objective and subjective color measurements were taken on the longissimus muscle at the 10th rib on d 14 postmortem. Loin chops were evaluated for sensory attributes, shear force, and retail display features. Pigs born outdoors were heavier and had a greater ADG at most growth intervals postweaning (d 28, 56, and 112; P < 0.05) than pigs born indoors. Pigs reared outdoors were heavier (P = 0.02) at d 140 (120.1 vs. 112.9 +/- 4.9 kg), and had higher (P = 0.01) ADG (2.2 vs. 1.9 kg/d) and gain:feed ratios (0.41 vs. 0.37) than did pigs reared indoors. Birth x rearing environment interactions were not significant (P > 0.10) for most measures. Carcass and meat quality measures did not differ (P > 0.05) among treatment groups, but loin chops from outdoor born or reared pigs had higher (P < 0.05) a* values than chops from pigs born or reared indoors. The LM muscle of pigs born outdoors had a higher (P < 0.01) percentage of type I, and a lower (P < 0.05) percentage of type IIA fibers than did pigs born indoors. Pigs reared outdoors had a higher (P < 0.01) percentage of IIA fibers and a lower (P < 0.05) percentage of IIB/X fibers than did pigs reared indoors for the LM and SM muscles. Outdoor production systems may influence growth, pork color, and muscle fiber types.  相似文献   

9.
Fibre type composition, activities of enzymes such as citrate synthase (CS), 3-hydroxyacyl coenzyme A dehydrogenase (HAD), lactate dehydrogenase (LDH), as well as glycogen, lactate and pH levels were analysed in muscle biopsies (m. gluteus medius) obtained after bullfighting from 10 young and 10 old bulls. No changes were seen in fibre type composition between groups, but the older bulls had higher HAD and LDH activities. Low glycogen concentrations and low pH values were found in both groups, but the lactate concentration after bullfighting was higher in the older group of bulls. The histochemical stain for glycogen revealed that type IIB fibres in both young and old bulls contained more glycogen than seen in type IIA and type I fibres. These results show that young and old bulls have similar muscle fibre type composition, but the metabolic capacity differs, with a higher glycolytic capacity and lactate production in older bulls. Furthermore, it seems that the physical and emotional stress in connection with a bullfight causes a marked depletion of glycogen, especially of type I and IIA fibres.  相似文献   

10.
The microstructure of two type of muscles was studied in a selection experiment conducted with Dutch Large White pigs (boars and gilts) selected for either low backfat thickness (L-line) or fast growth (F-line). Second- and fourth-generation pigs were used to determine effects of selection on fiber type composition, fiber area, and capillary density in the longissimus lumborum (LL) and biceps femoris (BF) muscles. Immediately after slaughter samples were taken from the LL and BF muscles. The latter was divided into an inside (BFi) and outside (BFo) portion, which refer to the red and white portions of the biceps femoris. Serial sections were stained for ATPase (pH 4.60), succinate dehydrogenase (SDH), and alpha-amylase-periodic acid shiff (PAS) to determine fiber type and capillary density. The LL and BFo muscles had predominantly type IIBw fibers, whereas the BFi muscle had a 2 to 4 times higher amount of type I fibers. In most muscles there were more type I and fewer type IIBw fibers in F- than in L-line pigs (P < .05), except in the LL muscle of second-generation pigs and in the red part of the BF muscle of fourth-generation pigs. In both selection lines lower type I and higher type IIBw percentages were found in muscles from gilts than in those from boars (P < .05). Capillary density and fiber area of L- and F-lines showed minor differences, which could be explained by differences in weight and age of the pigs of both lines. The results suggest that selection for low backfat thickness in pig breeding compared with increased growth rate resulted in fewer oxidative and more glycolytic muscle fibers. The magnitude of the effect depended on muscle type and duration of the selection period.  相似文献   

11.
Guo J  Shan T  Wu T  Zhu LN  Ren Y  An S  Wang Y 《Journal of animal science》2011,89(1):185-191
  相似文献   

12.
This research aimed to determine whether outdoor free-range rearing during the winter (average ambient temperature of 5 degrees C) vs. indoor housing (22 degrees C) affects meat quality, muscle metabolic traits, and muscle fiber characteristics. Forty Large White gilts and barrows were blocked by weight within each gender (20 per gender) and allotted randomly into two groups of pigs, with one reared indoors (IN) in individual pens (2.6 m2) and the other reared outdoors (OUT) from December to March in a 0.92-ha pasture. Both groups had free access to the same grower-finisher diet from 23 to 105 kg. At slaughter, adipose (backfat [BF] and omental fat [OF]) and muscle tissues (longissimus muscle [LM], rectus femoris [RF], and semitendinosus [ST]) were obtained from the right side of each carcass. Muscle fibers were stained and classified on the basis of stain reaction as slow-oxidative (SO), fast oxidative-glycolytic (FOG), and fast glycolytic (FG); fiber area and distribution were determined. Also assessed were carcass characteristics, initial and ultimate pH, L*a*b* values, drip loss percent, glycolytic potential (GP), and intramuscular lipid content, as well as the fatty acid profile of each muscle and adipose tissue. The OUT pigs had lower (P < 0.05) ADG and leaner (P < 0.05) carcasses than IN pigs. Rearing environment did not (P > 0.63) affect the intramuscular lipid content of the ST, but intramuscular lipid content was lower (P < 0.01) in the LM and tended to be higher (P = 0.06) in the RF of OUT than in those of IN pigs. In the BF outer layer of the OUT pigs, the higher PUFA content was compensated by both a lower (P < 0.01) saturated and monounsaturated fatty acid (MUFA) content, whereas in the OF, LM, and dark portion of the ST, only the percentage of MUFA was decreased (P < 0.01). In all tissues of the OUT pigs, the linolenic acid content was higher (P < 0.01) and the n-6:n-3 ratio was lower (P < 0.01). The GP of all muscles was higher (P < 0.01), and the ultimate pH of the RF and ST was lower (P < 0.01), in OUT compared with IN pigs. Lightness (L*) values were lower (P < 0.01) in the LM. Percentages of drip loss were higher (P < 0.05) in the LM and light portion of the ST of OUT than in those of IN pigs. The LM and RF of OUT pigs had more (P < 0.01) FOG and fewer (P < 0.01) FG fibers than muscles of IN pigs. Results suggest that rearing pigs outdoors increases aerobic capacity of glycolytic muscles but has little concomitant influence on meat quality traits.  相似文献   

13.
The characteristic myopathic features revealed by histological observations included strong proliferation of connective and fatty tissue, perivascular infiltrations and necrosis of muscle fibers with phagocytosis to the lesser extent. In the myopathic muscle, as well as in giant fibers, histochemical techniques showed a reduction in succinate dehydrogenase and lactate dehydrogenase activity in type beta R (slow-twitch, oxidative) and alpha R (fast-twitch, oxidative and glycolytic). Magnesium-activated adenosine triphosphatase reaction ranged from diffuse to negative in beta R, alpha R and alpha W (fast-twitch, glycolytic) fiber types. Diffuse reaction for acid phosphatase and total loss of glycogen content were observed. The micrographs of the myopathic muscle indicated enlarged mitochondria with atrophy or complete destruction of cristae. Many myofibrils were hypercontracted. Giant fibers possessed mitochondria enlarged to an even greater extent and many of the myofibrils had loss of continuity, were narrow, depleted and were also hypercontracted. Significant differences between myopathic and normal groups were found in number of beta R fibers (lower in the myopathic group), number of alpha R fibers and percent of alpha R and alpha W fibers (higher in the myopathic group). Differences (P less than .01) existed between meat pH1 value in the myopathic group (mean value of 5.95) and the normal group (mean value of 6.29). Meat from the myopathic group of pigs also had a lower (P less than .01) pH24 value and reduced water-holding capacity (P less than .01) relative to the meat of the normal pigs. The lack of difference of fattening and slaughter traits between the groups suggested that the White Zlotnicka pigs is of particular value because it is possible to improve the production traits without increasing the incidence of these syndromes within the breed. Negative correlations (P less than .05) between number of giant fibers and percent of alpha W fibers, and between percent of giant fibers and percent of alpha W fibers indicate that alpha W fibers can undergo degeneration and be transformed into giant fibers. Therefore, it it suggested that giant fibers should be treated as muscular, pathological results of past stresses and not as an additional type of normal muscle cells.  相似文献   

14.
Glycolytic potential of red, soft, exudative pork longissimus muscle   总被引：7，自引：0，他引：7  
Red, soft, exudative (RSE) pork is red as "normal" pork and exudative as PSE pork. The origin of RSE quality is unknown. In the present study, we determined whether the occurrence of RSE pork is related to the presence of the RN (Rendement Napole) gene. A glycolytic potential [= 2 x (glucose + glycogen + glucose-6-phosphate) + lactate] of > 180 micromol lactate/g of meat was used as indicator for presence of the RN gene. At 1 d postmortem, pork loin samples were collected at a commercial slaughter plant, and meat quality characteristics and glycolytic potential were determined. Glycolytic potential of RSE pork (n = 42) was higher (P < .01) than that of RFN (red, firm, nonexudative) pork (n = 25): 137 vs 110 micromol lactate/g of muscle. The glycolytic potential of PSE pork (n = 28) was 161 micromol lactate/g of muscle, which was higher (P < .01) than the glycolytic potential of RFN or RSE pork. Using a glycolytic potential of 180 micromol lactate/g of muscle as suggestive for the presence of the RN gene, four (10%) of the RSE samples were from RN carriers. By the same criterion, the PSE group contained nine (32%) RN gene carriers. These results suggest that the occurrence of RSE quality is not related to the presence of the RN gene.  相似文献   

15.
Residual feed intake (RFI) is defined as the difference between the observed feed intake and that expected based on requirements for maintenance and production. A divergent selection was conducted during 4 generations in Large White male pigs to produce low and high RFI lines. The present study aims at determining the influence of this selection on biochemical and histological traits of skeletal muscle, and relating these changes to correlated effects on growth, carcass composition, and meat quality traits. At 8 d preslaughter, biopsies from the LM were taken in the fed state on 14 females from each RFI line fed ad libitum. Animals were slaughtered at 107.8 ± 8.0 kg of BW without any previous fasting. Samples of LM, semimembranosus (SM), biceps femoris (BFM), and rhomboideus muscles were taken at both 30 min and 24 h postmortem. Myofiber typing was only assessed in LM. Low RFI pigs ("efficient") had leaner carcasses with greater muscle content (P < 0.001), less backfat thickness (P < 0.001), and less intramuscular fat content in all 4 muscles (P < 0.01 to P = 0.04). Their greater muscle content was associated with hypertrophy of all fast-twitch fibers. Glycogen content in all glycolytic muscles (i.e., LM, SM and BFM), was greater in low than high RFI pigs. The greater accumulation of glycogen in LM of low RFI pigs was specifically located in the fast-twitch glycolytic IIBW fibers, which correspond to fibers containing IIb, IIb + IIx, or IIx myosin heavy chains. The difference in muscle glycogen content between RFI line pigs was more significant in the living animals (P = 0.0003) than at 30 min postmortem (P = 0.08). This was associated with a decreased ultimate pH (P = 0.001), and greater lightness of color (P = 0.002) and drip loss (P = 0.04) in LM of low than high RFI line pigs, suggesting that selection for reduced RFI may impair some meat quality traits, such as water-holding capacity. Pigs from the low RFI line exhibited a greater (P = 0.02) percentage of IIBW fibers in LM and tended (P < 0.10) to have less lipid β-oxidative capacity in LM, SM, and BFM. In contrast, no difference (P > 0.10) between lines was found for citrate synthase and lactate dehydrogenase activities, mitochondrial activity, and expression of genes coding for uncoupling proteins 2 and 3. Differences between RFI pigs in plasma leptin, cortisol, and thyroid hormone concentrations are presented and discussed. In conclusion, selection for low RFI influenced muscle properties in a way favoring muscle mass, but likely impairing meat quality.  相似文献   

16.
The effect of animal maturity on fiber cross-sectional area, percentage of fiber types, activities of isocitrate dehydrogenase (ICDH) and lactate dehydrogenase (LDH), total and insoluble collagen and lipid concentration was investigated in the longis-simus thoracis (LT), semitendinosus (ST), and triceps brachii (TB) muscles. The analysis considered 2,642 muscle samples from bulls, steers, and cows of Aubrac, Charolais, Limousin, Montbéliard, and Salers breeds. For the bulls, the fiber cross-sectional area, percentage of slow oxidative fibers, and ICDH activity showed a quadratic relationship (P < 0.05), and the percentage of fast oxidative-glycolytic and fast glycolytic fibers and LDH activity showed a cubic relationship (P < 0.05) with increased maturity. A linear relationship was observed for the collagen and lipid muscle characteristics. The response equation coefficients for different muscles indicate that development of muscle characteristics is different for each muscle. Compared with the other muscles, ST muscle had a greater fiber cross-sectional area, proportion of fast glycolytic fibers, LDH activity, and collagen content. The LT muscle had a greater proportion of slow-oxidative fibers and lipid (P < 0.05). Within the ST muscle, all characteristics except lipid concentration showed different development between the breeds. Steers showed greater changes in muscle fiber cross-sectional area, percentage of fast oxidative-glycolytic and fast glycolytic fibers, and total lipid in the muscle with increasing maturity compared with bulls. The mean fiber cross-sectional area and percentage of fast glycolytic fibers was greater and the mean lipid concentration was less in bulls compared with steers (P < 0.05). Data for cows were from more mature animals. Muscle characteristics in cows did not show large changes with increasing degree of maturity. Muscle type accounts for a greater proportion of the variation in the muscle characteristics than breed and sex of the animal.  相似文献   

17.
For characterization of ether-extractable fat content (EE), L*, a*, and b* color, and water-holding capacity (WHC), 12 muscles or muscle groups were dissected from 48 pork carcasses of boars, barrows, or gilts that were fed diets either at minimum (LO) or 1% above (HI) their protein requirements and slaughtered in two separate trials at 100 or 110 kg. In both trials across muscles, gilts and boars had lower (P < .05) EE than barrows. In the 110-kg trial, boars had lower (P < .001) EE than gilts. In the 100-kg trial, boars on LO diets had lower (P < .001) WHC than all other groups, and both boar groups had lower (P < .05) WHC than gilts. No differences (P > .05) in WHC were seen in the 110-kg trial. In the 100-kg trial, gilts had lower L* (P < .05) than boars and barrows, but in the 110-kg trial boars had lower L* (P < .05) than barrows and gilts. The lowest (P < .05) a* values were for boars in the 100-kg trial and for boars on LO diets in the 110-kg trial. In both trials, the serratus ventralis had more (P < .001) EE than all other muscles. In both trials, the semitendinosus had higher (P < .001) L* and the longissimus had lower (P < .01) a* and b* than all other muscles. The numerous differences observed among muscles may help identify optimal uses for the entire pork carcass.  相似文献   

18.
The objective of this study was to examine the intralitter variation in postnatal growth performance, meat quality, and muscle fiber characteristics when littermates were categorized by carcass weight. Thirty-nine litters were weaned at 4 wk of age and had free access to feed from 2 wk of age until slaughter. They were slaughtered by litter at an average BW of 104 +/- 14 kg, and six pigs per litter were selected for analysis: the heaviest- (HW), middle- (MW), and lightest-weight (LW) pig of each sex. Categorizing littermates in LW, MW, and HW pigs at the same age reflected the differences in postnatal growth rate within a litter; thus ADG, muscle mass, and muscle deposition rate differed across pig weight groups (P < 0.001). Also, the total DNA content was different among pig weight groups (P < 0.001) and reflected differences in muscle growth rate. The difference in muscle growth rate between LW and MW pigs could be explained by a larger (P < 0.05) mean fiber area (MFA) in MW pigs, whereas the number of muscle fibers was similar. Growth rate differences between MW and HW pigs could in part be explained by a higher number (P < 0.01) of equal-sized muscle fibers in HW pigs. The difference in MFA was due to a higher estimated DNA and RNA content per muscle fiber in MW and HW compared with LW pigs (P < 0.05). Pigment content was higher in MW and HW compared with LW pigs (P < 0.01), but no other measured meat quality traits were significantly different across pig weight groups. These results indicate that both the number and the growth rate of muscle fibers contribute to intralitter variation in postnatal growth performance.  相似文献   

19.
Genetic selection in favor of muscle growth at the expense of fat should affect characteristics of muscles, and therefore beef quality. This study was conducted with two extreme groups of six animals selected among 64 Charolais young bulls ranked according to their genetic potential for muscle growth. Muscle characteristics were assessed in Rectus abdominis (RA, slow oxidative) and Semitendinosus (ST, fast glycolytic) muscles. Intramuscular fat content and proportions of myosin heavy chains I (slow) and IIA (fast oxido‐glycolytic) and certain indicators of oxidative metabolism (activities of citrate synthase (CS), isocitrate dehydrogenase and cytochrome‐c oxidase (COX); expression of H‐fatty acid binding protein (FABP)) were higher in RA than in ST muscle. Genetic selection for muscle growth reduced intramuscular fat content and the activities of some oxidative metabolism indicators (namely CS, COX only). The positive correlation between muscle triacylglycerol content and A‐FABP messenger RNA level (a marker of adipocyte differentiation) (r = 0.53, P < 0.05) suggests that A‐FABP may be a good marker of the ability of bovines to deposit intramuscular fat. In conclusion, the metabolic muscle characteristics which respond to the selection process in favor of muscle growth clearly differ from the muscle characteristics which allow muscle types to be differentiated.  相似文献   

20.
Ten healthy sedentary Thoroughbreds with previous race training experience were trained conventionally for 9 weeks. Muscle biopsy samples were obtained before and after training and after 6 weeks of detraining pasture rest. Biopsy samples were obtained from the right deltoid, triceps, vastus lateralis, middle gluteal, biceps femoris, and semitendinosus muscles. The deep-frozen biopsy samples were analyzed for activities of succinate dehydrogenase (SDH), 3-hydroxy-acylcoenzyme A dehydrogenase (HAD), and phosphorylase (PHOS) and for glycogen concentration. The triceps and gluteal muscle samples were also serially sectioned and stained for myofibrillar actomyosin adenosine triphosphatase (ATPase) activity after alkaline (pH 10.3) and sequential acidic (pH 4.34) ATPase inactivation. Fiber types I (alkaline preincubation), IIA1, IIA2, and IIA3 (sequential acidic preincubation over 5 minutes) were identified and were evaluated for fiber-type distribution and fiber areas. Increases in response to training were observed in deltoid and vastus muscle SDH and gluteal muscle HAD activities, and deltoid muscle glycogen concentration (P less than 0.05 to P less than 0.01). Changes in PHOS activity were not observed. Type-IIA1, -IIA2, and -IIA3 fiber areas in triceps muscle were increased in response to training (P less than 0.05 to P less than 0.01). Changes in fiber-type distribution did not occur in response to training. Changes in muscle enzyme activities, glycogen concentration, fiber types, and fiber areas were not seen from posttraining to detraining. Further increases were observed when detraining values were compared with pretraining values in deltoid, triceps, vastus, gluteal, and biceps femoris muscle SDH activities and in gluteal muscle glycogen concentration (P less than 0.05 to P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

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