Temperature alterations during embryogenesis have a sex-dependent influence on growth properties and muscle metabolism of day-old chicks and 35-day-old broilers.

Broiler eggs were either incubated at 37.8°C during the whole incubation period (control), or at higher (38.8°C, group H) and lower temperatures (36.8°C, group L) from embryonic day (ED) 7 up to ED 10 (ED 7 to 10) or from ED 10 up to ED 13 (ED 10 to 13). Before and after this temperature treatment the eggs were incubated at 37.8°C. The day-old chicks were weighted, sexed and fed up to day 35. On days 1 and 35 samples were taken from the breast and leg muscles for analyzing of the mitochondrial respiratory activity (MRA) and from the breast muscles for analysis of the cross-sectional areas (CSA) and the glycogen phosphorylase (GP), phosphofructokinase (PFK), lactate dehydrogenase (LDH), citrate synthase (CS) and cytochrome oxidase (COX) activities. Statistical analysis showed that treatment (control, group H, group L), sex and their interaction, but not the treatment period (ED 7 to 10; ED 10 to 13), significantly influenced the results. Group H chicks had lower (P⩽0.05) body and heart weights but higher (P⩽0.05) liver weights, CSA values, leg MRA as well as PFK, LDH, CS, GP and COX activities compared with the group L chicks. The results of the control chicks differ (P⩽0.05) from those of the group H (body, heart weight, COX), the group L chicks (liver weight, PFK, LDH, CS, GP) or the birds of both other groups (CSA). The group H broiler had higher (P⩽0.05) body and leg weights as well as LDH, CS, COX and GP activities than the group L broilers. The BWs and the LDH and GP results of the control broiler differ (P⩽0.05) from those of both other groups or from the results of the group H (CS) and group L broiler (COX). Female broilers had lower (P⩽0.05) body, breast and leg weights, but higher (P⩽0.05) CSA, LDH, CS and GP activities than the male animals. Analysis of treatment×sex interaction showed that group H hens had higher (P⩽0.05) body and breast weights, LDH and GP activities compared with the group L hens, whereas in the male broiler no effect of the interaction could be found, except for the lower (P⩽0.05) CSA values in the group H than group L cocks. The treatment effects are probably due to altered embryonic activity and related molecular mechanisms. The sex-related differences in the broiler indicate that these alterations already occur in the embryos and chicks, but become significant with the sexual dimorphism after hatch.

The Effect of Vibration Treatments Combined with Teriparatide or Strontium Ranelate on Bone Healing and Muscle in Ovariectomized Rats.

The aim of the present study was to study the effect of combined therapy of teriparatide (PTH) or strontium ranelate (SR) with whole-body vibration (WBV) on bone healing and muscle properties in an osteopenic rat model. Seventy-two rats (3 months old) were bilaterally ovariectomized (Ovx), and 12 rats were left intact (Non-Ovx). After 8 weeks, bilateral transverse osteotomy was performed at the tibia metaphysis in all rats. Thereafter, Ovx rats were divided into six groups (n = 12): (1) Ovx-no treatment, (2) Ovx + vibration (Vib), (3) SR, (4) SR + Vib, (5) PTH, and (6) PTH + Vib. PTH (40 µg/kg BW sc. 5×/week) and SR (613 mg/kg BW in food daily) were applied on the day of ovariectomy, vibration treatments 5 days later (vertical, 70 Hz, 0.5 mm, 2×/day for 15 min) for up to 6 weeks. In the WBV + SR group, the callus density, trabecular number, and Alp and Oc gene expression were decreased compared to SR alone. In the WBV + PTH group, the cortical and callus widths, biomechanical properties, Opg gene expression, and Opg/Rankl ratio were increased; the cortical and callus densities were decreased compared to PTH alone. A case of non-bridging was found in both vibrated groups. Vibration alone did not change the bone parameters; PTH possessed a stronger effect than SR therapy. In muscles, combined therapies improved the fiber size of Ovx rats. WBV could be applied alone or in combination with anti-osteoporosis drug therapy to improve muscle tissue. However, in patients with fractures, anti-osteoporosis treatments and the application of vibration could have an adverse effect on bone healing.

Effect of the Lipoxygenase Inhibitor Baicalein on Muscles in Ovariectomized Rats.

Sarcopenia, a loss of muscle mass accompanying osteoporosis, leads to falls and fall-related injuries. Baicalein, as a phytochemical agent, has an antioxidative and anti-inflammatory effect in muscle. In this study, sixty-one female Sprague Dawley rats were divided into five groups: four groups were ovariectomized (OVX) and one control group was nonovariectomized (NON-OVX). Eight weeks after ovariectomy, three disparate concentrations (1 mg/kg body weight (BW), 10 mg/kg BW, and 100 mg/kg BW) of baicalein were applied subcutaneously daily in three OVX groups. Mm. soleus, gastrocnemius, and longissimus were extracted; their diameter, area, relation to body, and muscle weights as well as number of capillaries per fibre were recorded. In Mm. soleus and gastrocnemius, the baicalein effect (increasing number of capillaries per fibre) was proportional to the dose applied. The fibre diameters and area under baicalein treatment were significantly greater compared to OVX and NON-OVX groups. In M. longissimus, we observed a shift to type IIa fibres. Serum creatine kinase levels were significantly lower in highest baicalein concentration group. We conclude that baicalein can stimulate angiogenesis, though not fibre type-specific, in skeletal muscle and reduce the estrogen-related loss of fibre diameter and area in the skeletal muscle in rats. Therefore, a protective effect of baicalein on muscle cells can be assumed.

Changing the incubation temperature during embryonic myogenesis influences the weight performance and meat quality of male and female broilers.

Eggs of broilers were initially incubated at 37.8°C, then at 38.8°C (group H) and 36.8°C (group L) between embryonic days 7 to 10 (time A) and days 10 to 13 (time B) and further incubated at 37.8°C until hatching. The chicks were fattened until day 35 and then slaughtered. The effect of treatment, time, and sex and their interactions on carcass and meat quality traits were determined. No significant impact of the "treatment time" was analysed, but "treatment" and "sex" and their interactions influenced (P < 0.05) the different parameters. After hatching, group L broilers were heavier (P < 0.05), followed by slower growth compared to group H chicken. At slaughter day, body, carcass, and leg weights of group H broiler were higher (P < 0.05) and yield results lower (P < 0.05) compared to group L animals. pH, drip loss, shear force, and lightness values of group H broiler breast muscles were higher (P < 0.05) and grill loss and redness values lower (P < 0.05) compared to group L Musculus pectoralis superficialis (MPS). Body, carcass, MPS, and leg weights, leg yields and grill loss and lightness values of the male broiler were higher (P < 0.05) and drip loss results lower (P < 0.05) than the female birds. Male group H broiler showed lower (P < 0.05) carcass and MPS yields compared to the control and group L males, whereas females group H birds had higher (P < 0.05) carcass and MPS weights and lower leg yields (P < 0.05) than the female group L animals. The study shows that an increasing incubation temperature during early embryogenesis positively influences the growth and carcass traits of the broilers, accompanied with a partly negative impact on meat quality (drip loss, shear force, lightness). The growth effects were sex-dependent, as significant weight differences could be only found in female broilers. The results indicate that incubation temperature alteration influences molecular mechanisms in the muscle and other tissues with an impact on growth after hatch.

The relationship of pork longissimus muscle pH to mitochondrial respiratory activities, meat quality and muscle structure.

The way the pH falls post-slaughter has an impact on meat quality. Pork longissimus muscles (n=48) were sorted in fast- (FG) (n=15) and normal glycolysing (NG) (n=33) muscles according to the post-slaughter pH 45 min values (FG<6.0; NG>6.0). FG muscles (5.84±0.04) compared with NG muscles (6.27±0.04) were accompanied with higher temperature, electrical conductivity, lightness and yellowness, and reduced grill loss and shear force values (P<0.05), but there were no pH-dependent changes of the drip loss and redness results. FG muscles had higher (P<0.05) percentages of fast-twitch glycolytic and lower proportions of fast-twitch oxidative and slow-twitch oxidative (P<0.05) muscle fibres. The study confirms the relationship of pH value to meat quality and muscle fibre characteristics also showing that pH values have no impact on intrinsic mitochondrial respiratory function.

Carcass Characteristics and Meat Quality of Swamp Buffaloes (Bubalus bubalis) Fattened at Different Feeding Intensities.

Twenty-four male 1-year old swamp buffaloes (Bubalus bubalis) were randomly allocated to 4 groups. One group grazed on guinea grass (GG) and another on guinea grass and the legume Stylosanthes guianensis (GL). The other two groups were kept in pens and fed freshly cut guinea grass and concentrate at an amount of 1.5% (GC1.5) and 2.0% (GC2.0) of body weight, respectively. The effect of the different feeding intensities on carcass characteristics and meat quality were assessed. The mean body weight at slaughter was 398 (±16) kg. Average daily gain was higher in concentrate-supplemented groups (570 and 540 g/d in GC1.5 and GC2.0, respectively) when compared to GG (316 g/d) and GL (354 g/d) (p<0.01). Likewise, the warm carcass weight was higher in GC1.5 and GC2.0 compared to GG and GL. Dressing percentage was 48.1% and 49.5% in GC1.5 and GC2.0 in comparison to 42.9% and 44.8% observed in GG and GL, respectively. Meat of Longissimus throracis from GC1.5 and GC2.0 was redder in color (p<0.01), while water holding capacity (drip and thawing loss) was improved in pasture-fed groups (p<0.05). Protein and fat content of Longissimus thoracis was higher in animals supplemented with concentrate (p<0.01), as was cholesterol content (p<0.05), whereas PUFA:SFA ratio was higher and n-6/n-3 ratio lower (p<0.01) in pasture-fed buffaloes. Results of the present study showed that the supplementation of pasture with concentrate enhances the growth and carcass characteristics of swamp buffaloes expressed in superior dressing percentage, better muscling, and redder meat with a higher content of protein and fat, whereas animals grazing only on pasture had a more favorable fatty acid profile and water holding capacity. In conclusion, the supplementation of concentrate at a rate of about 1.5% of body weight is recommended to improve the performance and carcass quality of buffaloes.

Can calcium chloride injection facilitate the ageing-derived improvement in the quality of meat from culled dairy cows?

This study investigated whether the positive effects of ageing on tenderness of meat from culled dairy cows can be facilitated by CaCl2. Injections of 250 mM CaCl2 solution (10% wt/wt) were performed on Longissimus dorsi samples from 32 7-yrs old cows. Samples were vacuum packaged and aged for 0, 1, 3, 5 and 7 days. Ageing alone produced lighter and less red meat with lower shear force, higher myofibrillar fragmentation and tenderness scores but also elevated lipid oxidation. For most traits investigated, CaCl2-injected meat exhibited similar ageing effects, but drip loss increased with age. The CaCl2-injected meat had a lower shear force and myofibrillar fragmentation increased more rapidly, but drip loss, off-flavour scores, colour stability and oxidative stability were inferior to untreated meat. Overall, it was found possible to accelerate tenderisation of such meat with CaCl2, but only at the cost of adverse effects in some other quality traits.

Physico-chemical and microbiological properties of raw fermented sausages are not influenced by color differences of turkey breast meat.

It has been suggested that the color of turkey breast meat influences both physico-chemical and microbiological properties of raw fermented sausages. In this study, raw fermented sausages were produced with turkey breast meat in 3 different colors (pale, normal, or dark), which were obtained from 2 fast-growing-genetic-line toms at 2 slaughterhouses. Prior to the sausage production, the breast muscles were sorted into color groups according to the lightness values determined at 24 h postmortem. This meat was subsequently processed to raw fermented sausages using 1.5 or 2.5% curing salt (CS). The pale meat had higher lightness, electrical conductivity, and drip loss, whereas the dark meat showed a darker color only. The physico-chemical (pH, water activity), visual (lightness, redness), and microbial (total plate count) properties of the sausages were not influenced by the color of the turkey breast meat. The sausage made with 2.5% CS had lower aw and higher ash and hardness values than the sausages produced with 1.5% CS. In conclusion, processing of differently colored turkey meat to raw fermented sausages does not influence the quality characteristics of the products. Based on these findings, there is no reason for the sausage producer to separate turkey breast muscles by color before producing raw fermented sausages.

Consumer acceptance of fermented sausages made from boars is not distracted by respective information.

This study investigated the impact of two information conditions and two androstenone concentrations on the acceptability of fermented sausages made from boar meat. Two batches of salamis were produced by mixing bellies and lean meat resulting in average androstenone levels of 0.408 µg/g vs. 1.585 µg/g melted fat, respectively. Skatole levels were kept below 0.05 µg/g melted fat in the final products. The consumers were provided with either the information that the products consisted of 100% pork or 100% boar meat. In total, 478 visitors of an animal husbandry fair, assumed to be familiar with the consequences of not castrating male piglets, evaluated the salami following a monadic between-subject design. The information did not significantly affect the hedonic scores. The percentage of dislikes was very low, i.e. 3 vs. 6% (p=0.24) for salami LOW and HIGH, respectively. The batch with lower androstenone content was liked slightly but significantly better (p=0.03).

Effects of a higher incubation temperature between embryonic day 9 and 12 on growth and meat quality characteristics of turkeys.

1. The study investigated the influence of manipulating incubation temperature for a short period on the post-hatch development up to week 16 in male and female BUT Big 6 turkeys. 2. Eggs were incubated at a control temperature of 37·5°C and 55% RH until d 18 when transferred to a hatcher at 37·5°C and 85% RH. For a 4 d period between embryonic day 9 (ED 9) and 12, eggs were incubated at 38·5°C and 55% RH (HT). 3. Birds were slaughtered at 16 weeks of age to analyse meat quality parameters of the Musculus pectoralis superficialis (MPS). 4. Across both incubation treatments, the turkey males had significantly higher live and breast weights, but lower breast yields than the females. The sex of the animals only influenced the yellowness of the MPS with lower values in the males. 5. Temperature manipulation resulted in significantly decreased live weights of HT birds compared with the control animals across all ages in both sexes. No impact of incubation treatment on meat quality characteristics was found. 6. The results indicate a negative effect of higher incubation temperature on the post-hatch growth, possibly by influencing the mechanisms that regulate the hypertrophic growth of the muscle fibres.

Mitochondrial respiratory and antioxidative enzyme activities in turkey meat.

Meat quality and (anti)oxidative metabolism of m. pectoralis superficialis (MPS), m. gastrocnemius (MG) and m. iliotibilialis lateralis (MIL) from turkey toms were analysed. After slaughter, pH of MPS and MG decreased and electrical conductivity of the MPS increased. The MG had generally higher pH values. The meat lightness (L) and redness (a) increased in MG and MPS after slaughter. The MPS always had higher L and lower a values. Mitochondrial respiratory activities (MRA) were higher in the MIL than the MPS. The activities of superoxide dismutase (SOD) and glutathione peroxidase, analysed in the MPS, increased and the glutathione reductase activity decreased after slaughter. Meat samples with lower pH24 h p.m. had higher drip loss and L values. The MRA were tendentially lower and the SOD activities higher in these samples. These results indicate a relation between the meat quality, the antioxidative metabolism and mitochondrial respiration.

Determination of pig sex in meat and meat products using multiplex real time-PCR.

For specific production lines, European retail companies demand exclusively female pork meat. To control the quality of their suppliers the identification and a quantitative detection of the animal sex origin of the meat is therefore of importance for meat processors. To enable a fast and reliable detection of male pig meat, a real time-PCR-system was designed in the present study. This was based on the genes AMEL-X and AMEL-Y. The real time-PCR assay allowed the detection of male pig meat at a concentration of 1% yielding a detection probability of 100% while the detection probability investigating meat samples containing 0.1% male pig meat was 44.4%. The analytic sensitivity of this system was assessed to be <5 pg DNA per PCR reaction. The assessment of the accuracy of the real time-PCR assay to correctly identify sex individuals was investigated with 62 pigs including males (n=29) and females (n=33) belonging to different breeds/lines. With the newly designed test all analysed animals were correctly sexed. No amplification was obtained with cow, goat, sheep, turkey and chicken genomic DNA. The presented assay can be used for sex diagnosis, for the detection of male pig meat and for meat quality control.

Prediction of the intramuscular fat content in loin muscle of pig carcasses by quantitative time-resolved ultrasound.

A novel method for non-destructive intramuscular fat (IMF) estimation via spectral ultrasound backscatter analysis of signals obtained from pig carcasses early post mortem is described. A commercial hand-held ultrasound device (center frequency: 2.7 MHz) was modified to focus the sound beam to the longissimus muscle at the 2nd/3rd last rib. Time-resolved ultrasound backscatter signals of loin muscle were recorded 45 min p.m. on 82 pig carcass sides. Backfat width (d(BF)=18.9±3.8 mm) and muscle attenuation (α(muscle)=.77±.15 dB MHz(-1) cm(-1)) were assessed from the measured pulse echo data. Other propagation properties of skin, backfat and muscle tissue obtained in a previous investigation were incorporated into the signal pre-processing to minimize parameter estimation artifacts. Spectral and cepstral parameters were derived from time-gated backscattered signals measured in the central muscle region. The range of intramuscular fat (IMF) determined by ether extraction was representative for German pig populations (.7%≤IMF(chem)≤3.6%, coefficient of variation CV(IMF(chem))=44.8%). Variations of IMF were associated with variations of backfat width (CV(d(BF))=20.2%), muscle attenuation (CV(α(muscle))=19.3%), and slope of the backscattered amplitude spectrum (CV(m)=28.8%). A full cross validated multiple linear regression model using these parameters resulted in good predictability of IMF(chem) (R(2)=.76, RMSEP=.34%). Among all tested carcasses, 73% could be correctly classified into one of three IMF classes (LOW: <1%, MID: 1-2%, HIGH: >2%). Using a single threshold (2% IMF), about 92% of all carcasses were correctly classified. With respect to the inherent variability of IMF within a single muscle and the different tissue volumes used for the chemical and ultrasound based IMF estimations the remaining prediction errors are acceptable. Compared to previous ultrasound based studies, the number of acoustic parameters used for the IMF prediction could be reduced. Moreover, the used parameters are based on time-of-flight and spectral slope estimations, which are i) more robust with respect to measurement artifacts and ii) have a causal link to structural variations associated with IMF variations in pork loin.

Color values and other meat quality characteristics of breast muscles collected from 3 broiler genetic lines slaughtered at 2 ages.

Broilers from the lines Ross 308, Ross 708, and Cobb 700 were slaughtered at 28 and 41 d of age at a commercial abattoir. After slaughter, the carcass, breast, and leg weights as well as the breast and leg yields were determined. Further investigations analyzed the color [lightness (L*), redness (a*), and yellowness (b*)], pH at 24 h postmortem, electrical conductivity (EC), drip loss, grill loss, and shear force values as well as the muscle fiber cross-sectional areas of the breast muscles. The 41-d-old broilers had higher carcass, breast, and leg weights than the 28-d-old birds. The breast yield values were higher and the leg yields were lower in the 41-d-old broilers. The fiber cross-sectional area values were also higher in the older birds. Within the younger birds the slaughter characteristics were approximately comparable among the lines. The EC, L*, grill loss, and shear force values increased but the drip loss and a* values decreased with the age of the broiler. The genetic lines differed within the 28-d-old broilers with regard to EC, grill loss, and shear force values and within the 41-d-old broilers with regard to the EC, L*, grill loss, and shear force values. The pH correlated negatively with the EC, L*, b*, drip loss, and shear force values. During storage, L* and b* values of the breast muscles increased and a* values decreased in all genetic lines, whereas the L* values were generally higher in the older broilers and the a* and b* results were generally higher in the breast muscles of the younger broilers. In conclusion, the carcass and meat quality characteristics of broilers changed with age with positive (carcass and breast muscle weight, drip loss) but also negative (L*, a*, grill loss) effects. The effect of the genetic line was rather low. Despite the age-related changes of meat quality parameter, the pH values remained unchanged, indicating muscle structural influences on the muscle-to-meat-transition with increasing age of the broiler.

Adenine nucleotide concentrations and glycolytic enzyme activities in longissimus muscle samples of different pig genotypes collected before and after slaughter.

Longissimus muscle samples from the pig genotypes Duroc (Du), Pietrain (MHS homozygote negative (PiNN), positive (PiPP)) and a Duroc-Pietrain crossbreed (DuPi) were analyzed. The PiPP samples showed a faster pH drop and higher electrical conductivity, drip loss and lightness values. Before slaughter the concentrations of the adenine nucleotides were comparable between the genotypes, but 40 min after slaughter (p.m.) the ATP concentrations decreased and IMP increased, to a higher extent in the PiPP pigs. The nucleotide values of the 12 h p.m. samples were again comparable. Activities of glycogen phosporylase (GP), phosphofructokinase (PFK) and lactate dehydrogenase (LDH) were nearly similar before slaughter. Forty minutes after slaughter the LDH activities increased in all pigs and the PFK activities in all genotypes but not in the PiPP. GP results were rather inconsistent indicating an earlier activation of this enzyme. The study showed that the reduced meat quality in the PiPP pigs is accompanied with rapid ATP degradation and accelerated enzyme activation.

Mitochondrial respiratory and antioxidative enzyme activities in broiler meat in relation to age and gender of the animals.

Colour is an important quality parameter of broiler meat influencing the consumer buying behaviour. The alterations of the colour after slaughter are related to the oxidative status of the tissue. This in turn is influenced by an interaction between the mitochondria and the antioxidative enzymes. In this study, breast muscles were collected from hens and cocks of a commercial line slaughtered at the ages of 28 and 41 day. Analysis of the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) was performed with samples obtained 20 min and 48 h after slaughter (post mortem, p.m.), whereas the mitochondrial respiratory activity was analysed in permeabilised breast muscle fibres collected 20 min p.m. The carcass characteristics of breast muscle and leg weight as well as breast yield were significantly higher, and the leg yields lower, in the 41-day-old broiler. The 28-day-old hens and cocks had comparable carcass characteristics (P > 0.05), whereas 41-day-old cocks had significantly higher carcass, breast and leg weight in comparison to the hens. The pH20 min p.m. and the L*48 h p.m. were significantly higher, and the a* and b* values of the 20 min and 48 h p.m. samples as well as the drip loss were significantly lower in the 41-day-old broiler. Mitochondrial respiratory rates were comparable (P > 0.05) between the 28- and 41-day-old cocks and hens. The same result could be found with regard to the activities of the SOD, GPx and GR except for lower activities of the SOD20 min p.m. and higher of the GR48 h min p.m. in the 41-day-old broiler. The concentrations of thiobarbituric acid-reactive substances were generally higher in the breast muscles of the 41-day-old broiler. Assorting the data according to their mean pH20 min p.m. indicates a positive influence of higher pH values (>6.34) on the mitochondrial function, whereas a low pH20 min p.m. results in tendentially and significantly higher activities of the antioxidative enzymes and drip loss values. These results indicate a relation between the meat quality and the oxidative metabolism as well as antioxidative capacity of the meat.

Changes of the activities of glycolytic and oxidative enzymes before and after slaughter in the longissimus muscle of Pietrain and Duroc pigs and a Duroc-Pietrain crossbreed.

After slaughter of pigs, the pH of the meat decreases due to lactate accumulation within the tissue. In addition to calcium homeostasis, energy metabolism plays a key role during the muscle-to-meat transition, and it is interesting to know how specific enzymes of the glycolytic and oxidative pathways change during this process, especially in relation to the antemortem situation, and if there is an impact of these alterations on the meat quality characteristics. Therefore, in the present study samples of the LM from the pig genetic groups Pietrain (Pi), Duroc (Du), and a Du × Pi crossbreed population (DuPi) were collected 24 h before as well as 1 min, 40 min, and 12 h after slaughter, and the activities of the glycogen phosphorylase (GP), phosphofructokinase (PFK), lactate dehydrogenase (LDH), citrate synthase (CS), NADH-ubiquinone oxidoreductase (complex I), and cytochrome oxidase were analyzed. Additional investigations include carcass and meat quality characteristics as well as the microstructure of the LM. The Pi breed had greater (P < 0.05) carcass yield and lean meat values, but no differences (P > 0.05) of the meat quality traits could be determined between the investigated pig breeds. The Pi pigs exhibited a greater (P < 0.05) percentage of fast-twitch glycolytic and had smaller amounts (P < 0.05) of slow-twitch-oxidative fibers in comparison with the Du pigs. The enzyme activities of the GP, PFK, and complex I increased (P < 0.05) immediately after slaughter (1 min postmortem) of the pigs and the activity of the LDH within 40 min postmortem. After 12 h, the GP, PFK, LDH, and complex I activities decreased to the amount of the preslaughter sample. No differences could be found with regard to the enzyme activities of the CS and cytochrome oxidase at all determination times. Considering the enzyme activities within the different breeds, the Pi pigs exhibited greater (P < 0.05) GP and PFK and the Du animals exhibited greater (P < 0.05) CS and complex I activities. The study indicates that the glycolytic enzymes GP, PFK, and LDH as well as the complex I influence the muscle-to-meat transition process after slaughter of the animals without an impact on the muscle quality. The activities of the GP, PFK, CS, and complex I reflect the differences of the muscle fiber composition between the Pi and Du pigs.

Mitochondrial respiratory activity in porcine longissimus muscle fibers of different pig genetics in relation to their meat quality.

The pig genetics of Duroc, Pietrain (MHS homozygote negative, PiNN), Pietrain (MHS homozygote positive, PiPP) and a F2-Duroc-Pietrain cross-breed were analyzed. The animals had comparable (P>0.05) carcass weights, but the PiPP pigs had higher carcass yield and lean meat values (P<0.05). Considering the meat quality characteristics, the PiPP showed a faster pH drop and higher electrical conductivity, drip loss, shear force as well as lightness and redness values (P<0.05). The PiPP animals had less slow-twitch-oxidative (STO) and more fast-twitch-glycolytic (FTG) muscle fibers, whereas the results of the Duroc animals were converse (P<0.05). The STO and FTG fibers of the PiPP animals were larger than those of the other genetics (P<0.05). The analysis of the mitochondrial respiratory activity (MRA) using permeabilized longissimus muscle fibers resulted in no differences between the pig genetics before and immediately after slaughter. During chilling the MRA decreased in all pigs but to a higher extent in the PiPP pigs (P<0.05).

Assessment of beef production from Brahman x Thai native and Charolais x Thai native crossbred bulls slaughtered at different weights. I: growth performance and carcass quality.

Effects of genotype and slaughter weight on growth performance and carcass quality of Brahman x Thai native (BRA) and Charolais x Thai native (CHA) crossbred bulls were studied. Thirty-four BRA and 34 CHA bulls raised under practical fattening beef farm conditions were randomly selected and slaughtered at 500, 550 and 600 kg live weight, respectively. Parameters of growth performance, carcass quality and commercial prime cuts were determined. Results showed that growth performance and carcass quality of CHA was better, since they showed higher weight gain, better body muscle score, higher carcass weight high dressing percentage, higher carcass muscle, less carcass fat and bone plus connective tissue proportions, better carcass classifications, greater loin eye area and higher commercial prime cut percentage. Slaughter weights up to 600 kg resulted in increased carcass weight, loin eye area and percentage of commercial prime cuts and can therefore be recommended.

Assessment of beef production from Brahman x Thai native and Charolais x Thai native crossbred bulls slaughtered at different weights. II: meat quality.

The objective was to assess meat quality of Brahman x Thai native (BRA) and Charolais x Thai native (CHA) crossbred bulls. In total 34 BRA and 34 CHA under practical farm conditions were randomly assigned for slaughter at 500, 550 and 600 kg live weight, respectively. Longissimus dorsi muscle was taken for meat quality and sensory evaluations. CHA meat had higher intramuscular fat, exhibited higher marbling scores and relatively better colour than BRA meat. Although muscle fiber area was similar for both genotypes, shear force values were higher for CHA meat. Water holding capacity was better for CHA meat shown by lower 7-day ageing, thawing and grilling losses. However, the sensory evaluation ratings were similar for both genotypes. Increasing slaughter weight from 500 kg up to 600 kg had no significant effect on meat quality. In conclusion, meat quality of CHA was superior to BRA.