An experiment was conducted to evaluate the effects of the RN genotype on skeletal muscle characteristics in pigs sharing otherwise the same polygenic background. Animals were genotyped for RN on the ...basis of RTN (Rendement Technologique Napole) records using segregation analysis methods. Samples of longissimus (L) and semispinalis capitis (S) muscles were taken from 39 rn+/rn+, 38 RN-/rn+ and 37 RN-/RN- pigs slaughtered at 108 +/- 8.6 kg live weight. Activities of lactate dehydrogenase (LDH), citrate synthase (CS), and beta-hydroxy-acyl-coenzyme A dehydrogenase (HAD) were measured on both muscles to assess glycolytic, oxidative, and lipid beta-oxidation capacities, respectively. Histological examinations and chemical analyses were performed on L muscle. The energetic metabolism of the white L muscle was more oxidative in RN-/RN- than in rn+/rn+ pigs, as shown by increased CS and HAD activities (P < .001), decreased LDH activity (P < .001), larger cross-sectional area of IIA (P < .05) and IIB-red (P < .05) fibers, higher relative area of IIA fibers ( P < .05), and lower relative area of IIB-white fibers (P < .001). No significant difference was found between heterozygous and homozygous carriers of the RN- allele, except for CS activity, which was lower in RN-/rn+ than in RN-/RN- pigs. In L muscle, the RN- allele led to a large increase in glycolytic potential (+3.5 phenotypic SD between homozygotes) and lightness (+.7 SD), and a decrease in ultimate pH, dry matter, and protein contents (-1.7 to -2 phenotypic SD for these three traits), with an almost completely dominant effect. No differences were found between genotypes for intramuscular fat and hydroxyproline contents. In the red S muscle, the presence of RN- had no influence on enzyme activities. These results indicate that the RN genotype greatly influences compositional and histochemical traits and metabolic enzyme activities in a muscle type-dependent manner, with a completely or incompletely dominant effect of the RN- allele.
The objective of this study was to investigate the effects of the halothane (HAL) genotype, slaughter weight (SW), and the HAL x SW interaction on compositional and textural traits of raw and cooked ...pork. Pigs were bred to exhibit one of the three HAL genotypes (NN, Nn, and nn) with otherwise equivalent genomes. The nn halothane reactors are known to typically produce PSE pork, whereas NN pigs do not typically produce PSE pork. Pietrain x Large White gilts and boars, all with verified Nn genotype (by DNA test), were mated to obtain F2 littermates of the three HAL genotypes. These pigs were slaughtered at either 101 +/- 3 ("light") or 127 +/- 3 ("heavy") kg BW and were evaluated for longissimus muscle traits. The pH at .5 h after death (pH1) was 6.35, 6.13, and 5.68 in NN, Nn, and nn pigs, respectively. Sarcomere length was greater in nn than in NN and Nn pigs (1.94 vs 1.83 and 1.85 microm, respectively). Mechanical resistance was higher in nn than in NN pigs for both raw and cooked meat. Meat from nn pigs was judged by a trained panel to be less rough, more cohesive, harder, more fibrous, less granular, more elastic, and less easy to swallow than meat from NN pigs. For most traits under study, the heterozygotes were intermediate between the homozygotes but closer to NN than to nn pigs. Muscle from heavy pigs had longer sarcomeres and less moisture than muscle from light pigs. The n allele of the HAL gene unfavorably affects pork texture, and this effect is maintained throughout the range of 101 to 127 kg BW.
Summary
The aim of this study was to analyse the effect of polymorphism of calpastatin (CAST) and RYR1 genes for some meat quality traits taking into consideration the group of meatiness and their ...mutual interactions. Investigations were carried out on a group of 201 fatteners which were crosses of four breeds. The results obtained show that CAST/MspI genotype has an effect close to the major effect for drip loss from LL muscle tissue at 48 h as well as at 96 h postmortem (0.92 and 0.96 SD respectively). Among the meat quality traits analysed and that were affected by CAST/MspI genotype, the animals with BB genotype at this locus were characterized by the most profitable values of all these traits. Significant interactions between CAST and RYR1 genotypes observed indicate that the quality of meat influenced by RYR1 genotype may be modified by the simultaneous influence of genotype as regards the CAST locus.
The Biceps femoris muscles from 50 hams were used in the study. Ten samples were taken for analysis on the day after slaughter. Forty hams were dry-cured and taken for analysis by groups of 10 at ...days 74, 81, 179 and 273 after the beginning of processing. Volatile compounds were extracted from the middle part of the Biceps femoris muscle by dynamic headspace extraction, then analysed by gas chromatography and mass spectrometry. More than 100 peaks were detected, among which 74 were identified and 52 were quantified. Most identified compounds originated from either lipid oxidation or amino acid degradation. The total quantity of extracted compounds increased dramatically between day 0 and day 74. Propanone was by far the most abundant compound, followed by the other ketones, alcohols and aromatic hydrocarbons (66.5, 9.9, 9.2 and 8.4% of the total chromatogram area, respectively, at the end of processing). The levels of individual compounds varied greatly during processing. There was some evidence of independence between the reactions producing volatile compounds from lipids and those involving amino acids.
Biceps brachii muscle was isolated from anaesthetized New Zealand rabbits and perfused for 30 min with bovine red cells, while electrically stimulated at 0.1 Hz, 50 V. Temperature was maintained at ...34 (physiological temperature of this muscle), 36 or 38 °C in the first experiment (Exp 1). In the second experiment (Exp 2), temperature was maintained at either 34 or 38 °C and the muscle was perfused with 2 ng/ml adrenaline and 10 ng/ml noradrenaline for 5 min during the perfusion. Whatever the temperature, twitch force decreased (
P<0.01) during perfusion indicating muscular fatigue. Total turnover rate of “energy-rich” phosphate was higher at 38 °C than at 34 °C (
P<0.05) during the first 30 min after the perfusion was stopped in Exp 1 and tended to be higher between 30 and 60 min (
P<0.10) in Exp 2. Catecholamine perfusion had no effect on contraction and on muscle metabolism whatever the temperature. Our results show that an increase in temperature of 4 °C above the physiological temperature decreases the resistance of oxygenated rabbit muscle to fatigue. In anoxic muscle, temperature increase accelerates the turnover of “energy-rich” phosphate compounds, which is known to be detrimental to meat quality.
Twenty-week-old Friesian-Holstein calves were used to assess the influences of the duration of feed withdrawal before transport (1 or 11 h) and of transport time (1 or 11 h) on carcass and muscle ...characteristics and meat sensory qualities. One hundred twelve calves were used for live weight and carcass measurements, following a 2 x 2 factorial design (28 replicates). Twelve calves were randomly selected in each treatment group to examine muscle characteristics and sensory quality of longissimus lumborum (LL) and semimembranosus (SM). Long transport (11 h) increased loss in live weight (P < .001) and dressing percentage (P < .001). Feed withdrawal for 11 h also increased dressing percentage (P < .001). Long transport resulted in decreased liver weight (P < .05), glycolytic potential (P < .01), and pH at 4 h postmortem (P < .05) in the LL. Drip loss, compositional traits, cooking loss, and sarcomere length in the LL, as well as drip loss, pH values, compositional traits, cooking loss, and sarcomere length in the SM, were unaffected by the treatments. However, long transport decreased tenderness score in the LL (P < .05) and SM (P < .01). It also increased myofibrillar resistance (P < .001) in the latter muscle. The results demonstrate an unfavorable effect of long transport on the sensory quality of veal. This effect cannot be explained on the basis of differences in pH values and(or) compositional characteristics.
Pigs of the same genetic type at the RN and HAL loci, i.e. rn
+RN
−/NN were reared in similar conditions of feeding and housing. They were slaughtered in two abattoirs (referred to as A1 and A2) ...using a mixture of air (30%) and CO
2 (70%), at a rate of 300 pigs per hour per slaughterline. One hundred and thirty-two pigs from 11 farms were slaughtered in A1 using a corusinga restrainer and 127 pigs from 5 farms were slaughtered in A2 with the backloading technique. pH at 40 min, 2.5 h and 24 h after slaughter and colour (
L*,
a*,
b*) at 24 h after slaughter were measured in the
semimembranosus muscle. Meat quality of the ham was scored as follows: 1, no PSE-zone; 2, doubtful; 3, PSE-zones in the
semimembranosus and sometimes on the internal flexor muscles; 4, PSE-zones in all the flexor muscles. The muscle pH value was higher in A2 than in A1 at 40 min post mortem (
P<0.01), but not at 2.5 and 24 h.
L* (
P<0.001) and
b* (
P<0.05) were higher in A1 than in A2. There was a remarkable difference in meat quality scores, with 50% of the hams scoring 3 or 4 in A1, vs 13% in A2. Lairage time before slaughter affected (
P<0.01) the pH value at 2.5 h (5.69 vs 5.93). The values of pH1 and pH2.5 decreased with increasing the meat quality score. The values of
L* and
b* increased markedly with the score. The results of the present study indicate that the method of bringing the slaughter pigs to the stunning device affects the frequency and importance of PSE meat in the ham. The automated driving of groups of animals to the stunning machine combined with the backloading of a nacelle, compared to a traditional system driving pigs in single file using electrical goads and a restrainer was beneficial with respect to both meat quality and animal welfare.
Rabbit triceps brachii muscle was perfused with bovine red cells medium. Changes in phosphorus compounds and intracellular pH were followed using
31P NMR during 15 min in the perfused muscle and ...during 50 min in muscle made anoxic by perfusion stop. Potassium levels in perfusate was maintained at 4 mM (normal plasma concentration at rest) during all perfusion in one muscle and at 4 mM for 10 min then 10 mM during 5 min before perfusion stop in the contralateral muscle. The intracellular pH and phosphorylated compounds content remained stable in the perfused muscle whatever the potassium concentration of the perfusate. Five min after perfusion stop a decrease in phosphocreatine (
P<0.05) and pH (
P<0.01) and an increase in sugar-phosphates (
P<0.01) were observed independently of potassium concentration. The lack of effect of increasing circulating potassium indicates that hyperkalemia does not affect, by itself the muscles energetic metabolism.
