Biochemical alterations in the Musculus triceps brachii and Musculus longissimus thoracis during early postmortem period in pigs.

Muscle-to-meat-transition is influenced by alterations of the energy metabolism. Porcine Musculus triceps brachii (MT) consisted of more fast-twitch-glycolytic muscle fibers and samples, collected 0, 10 and 20 min after slaughter (p.m.), showed higher mitochondrial respiratory activities and ATP concentrations than Musculus longissimus thoracis (LT) samples. Enzyme activities in MT were higher at 0 min (glycogen phosphorylase (GP)), 10 min (GP, citrate synthase (CS)) and at 20 min p.m. (CS). However, LT results were higher at 0 min (lactate dehydrogenase (LDH)), 10 min (phosphofructokinase (PFK), LDH) and at 20 min p.m. (PFK, F0F1-ATPase (F0F1)). Between 0 min and 10 min p.m. CS activities decreased in LT and MT samples, PFK increased in LT and GP in MT samples. Between 10 min and 20 min p.m. PFK and LDH decreased in LT and GP in MT samples, whereas F0F1 increased in LT and CS in MT samples. The data indicate that muscles with different mitochondria contents show clearly different energy metabolism characteristics.

The Advantages of Bilateral Osteotomy Over Unilateral Osteotomy for Osteoporotic Bone Healing.

Most models of osteoporotic bone fractures are performed unilaterally (UL). We investigated healing of tibia osteotomy performed either UL or bilaterally (BL) in ovariectomized rats. Behavior of animals and muscle structure were assessed. Three-month-old female Sprague-Dawley rats were ovariectomized (n = 32). After 10 weeks, half the rats underwent UL osteotomy of tibia metaphysis (right limb) with plate osteosynthesis. The other rats were osteotomized BL. Half of the rats in each group received either standard pain treatment with carprofen (5 mg/kg body weight (BW), 1x/day for 2 days) or carprofen and buprenorphine (5 mg/kg BW, 1x/day and 0.03 mg/kg BW, 2x/day for 5 days) after osteotomy. The UL rats started to load the injured limb from day 27 ± 9; BL rats did this from day 4 ± 4 onward. The UL rats more frequently loaded only one hind limb; BL rats more often loaded both hind limbs. Osteotomy was not bridged in 20% of UL rats and in 4% of BL rats. Callus volume and bone volume fraction were lower in UL group. Weight and fiber size of UL-intact limb muscles were enhanced, compared to the osteotomized limb and those in BL group. Most of the other parameters which assess physiology, activity, body posture, head, or coat were not different. The effect of two pain therapies was not significant on any variable studied. Welfare of the animals was acceptable in all rats. In UL rats, bone healing was delayed. The more advanced healing in BL rats suggested a positive effect of earlier loading. In studies on bone healing, it is advisable to perform BL osteotomy.

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.

Effect of a nano-silver coating on the quality of fresh turkey meat during storage after modified atmosphere or vacuum packaging.

Nano-silver is used in consumer products due to its antibacterial properties. The aim of this study was to evaluate the effect of a nano-silver-coated film on the quality of turkey meat during vacuum-sealed and modified atmosphere packaging up to 12 days of storage. In the first part of the experiment, turkey breasts were packaged using either vacuum packaging or modified atmosphere packages (MAPs) and contained films with or without a nano-silver coating (control film). Parameters such as pH, electrical conductivity, color (lightness L*, redness a*), myoglobin redox forms, thiobarbituric acid-reactive substances (TBARS), biogenic amines (BAs), total viable bacterial counts, Pseudomonas species counts, and Enterobacteriaceae species counts were evaluated on storage days 4, 8, and 12. In the second part of the study, the antimicrobial effect of a nano-silver-coated film on turkey breast was evaluated after inoculation with Escherichia coli (E. coli). Turkey meat packaged with the nano-silver film exhibited lower a* values on days 1 (3.15 ± 0.62), 4 (3.90 ± 0.68), and 8 (4.27 ± 0.76) compared to the packaged meat with the control film (3.41 ± 0.73, 4.35 ± 0.94, 4.85 ± 0.89, respectively), indicating special optical properties of nanoparticles. Concerning the BAs, silver packaged meat showed higher values of tyramine on day 12 (1274 ± 392 ng/g meat) and cadaverine on day 4 (1224 ± 435 ng/g meat) compared to the normal packaged products (647 ± 576 and 508 ± 314 ng/g meat, respectively). MAP meat revealed higher L* and TBARS values and lower microbial counts than the vacuum packaged products on all days. The MAP meat also showed lower a* results on days 4 and 8 and higher metmyoglobin (metMb) values on days 8 and 12 compared to th E: vacuum products. In the inoculation study, the microbial counts of the turkey meat were comparable between the two film types. The study showed that the nano-silver coating did not exhibit any advantageous effects on the quality and microbiological parameters of the turkey meat.

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.

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.

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.

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.

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.

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.

MAPK/ERK kinase (MEK) signalling is required for resumption of meiosis in cultured cumulus-enclosed pig oocytes.

Resumption of meiosis of mammalian oocytes is facilitated by the maturation promoting factor (MPF) and accompanied by activation of mitogen activated protein kinases (MAPK) which are phosphorylated by the MAPK kinase (MEK). In this study we examined the effects of PD 98059, which inhibits the activity of MEK, on in vitro maturation of pig oocytes. Cumulus-oocyte complexes (COCs) were cultured in the presence or absence of the drug (50 microM) for various time periods. To elucidate the influence of cumulus cells, COCs were first cultured in inhibitor-free medium, subsequently denuded, and incubated further in PD 98059 supplemented medium. Reversibility of drug action as tested following PD 98059 treatment of COCs by transferring them to drug-free medium. Culture of COCs in medium supplemented with PD 98059 prevents resumption of nuclear maturation in the majority of COCs. This inhibition was reversible and accompanied by a non-activation of both MAP and MPF. Addition of the MEK inhibitor to extracts of in vitro matured oocytes revealed that the kinase activities were not directly influenced by the inhibitor, suggesting a link between MAP and MPF kinases. Preincubation of COCs in inhibitor-free medium for 6 h followed by further culture of COCs or denuded oocytes in the presence of PD 98059 for various periods resulted in elevated MAP and MPF kinase activities, indicating an early and transient MEK signalling in the oocyte itself. These results support the idea that MAP and MPF are involved in the induction of germinal vesicle breakdown in porcine oocytes.

Roscovitine, a specific inhibitor of cyclin-dependent protein kinases, reversibly inhibits chromatin condensation during in vitro maturation of porcine oocytes.

In the present study the effects of roscovitine on the in vitro nuclear maturation of porcine oocytes were investigated. Roscovitine, a specific inhibitor of cyclin-dependent protein kinases, prevented chromatin condensation in a concentration-dependent manner. This inhibition was reversible and was accompanied by non-activation of p34cdc2/histone H1 kinase. It also decreased enzyme activity of MAP kinase, suggesting a correlation between histone H1 kinase activation and the onset of chromatin condensation. The addition of roscovitine (50 microM) to extracts of metaphase II oocytes revealed that the MAP kinase activity was not directly affected by roscovitine, which indicates a possible link between histone H1 and MAP kinase. Chromatin condensation occurred between 20 and 28 h of culture of cumulus-oocyte complexes (COCs) in inhibitor-free medium (germinal vesicle stage I, GV1: 74.6% and 13.7%, respectively). Nearly the same proportion of chromatin condensation was detected in COCs incubated initially in inhibitor-free medium for 20-28 h and subsequently in roscovitine-supplemented medium (50 microM) for a further 2-10 h (GV I: 76.2% and 18.8%, respectively). This observation indicates that roscovitine prevents chromatin condensation even after an initial inhibitor-free cultivation for 20 h. Extending this initial incubation period to > or = 22 h led to an activation of histone H1 and MAP kinase and increasing proportions of oocytes exhibiting chromatin condensation in the presence of roscovitine. It is concluded that histone H1 kinase is involved in the induction of chromatin condensation during in vitro maturation of porcine oocytes.

Impact of various glycosaminoglycans upon cAMP-dependent protein kinase.

The physiological effects of the second messenger cAMP are displayed by cAMP-dependent protein kinase-medicated phosphorylation of specific target proteins which in turn control diverse cellular functions. We have determined this enzyme substrate phosphorylation in the presence of various glycosaminoglycans using a cAMP-dependent protein kinase isolated from rat liver. The results indicate that sulfated and unsulfated polysaccharides are able to inhibit phosphorylation of histone type IIa catalysed by cAMP-dependent protein kinase. Based on their impact upon substrate phosphorylation, glycosaminoglycans can be divided into three groups: group I with the highest inhibitory effect: dermatan sulfate and heparan sulfate; group II: chondroitin 4-sulfate and group III with the lowest inhibitory effect: chondroitin 6-sulfate, keratan sulfate and hyaluronic acid.

Modulation of cAMP-dependent protein kinase by derivatives of chondroitin sulfate.

Here, we report investigations about the direct effect of glycosaminoglycans, such as dermatan sulfate, chondroitin 4- and 6-sulfate upon cAMP-dependent protein kinase activity. The results indicate that glycosaminoglycans strongly influence the phosphorylation activity of this enzyme against histone type IIa and [Val6, Ala7]-kemptide. While chondroitin 4-sulfate and dermatan sulfate exhibit inhibitory effects, chondroitin 6-sulfate shows a stimulating effect. In addition, the chondroitin 6-sulfate is also able to reduce the chondroitin 4-sulfate and dermatan sulfate specific inhibition.