Browsing by Subject "MEAT QUALITY"

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  • Liu, Jiao; Puolanne, Eero; Schwartzkopf, Matthias; Arner, Anders (2020)
    The "Woody" or "Wooden" breast disease is a severe myopathy of pectoralis major muscle recently identified within rapidly growing broiler lines all around the world with a prevalence rate around 20%, or even higher. Although of significant ethical and economic impact, little is known regarding the structural and functional aspects of the contractile apparatus in the woody breast muscle. The aim of the present study was to determine physiological properties of the contractile system in the morphologically intact muscle fibers of focally damaged woody breast in comparison with normal muscle fibers to gain insight into the muscle function of the animal and possibly mechanisms involved in the disease development. Muscle samples were taken from woody breast (non-lesioned areas) and normal breast muscles from broilers. Length-tension curves, maximal active stress, maximal shortening velocity, calcium sensitivity, rate of tension development, lattice spacing and muscle biochemical composition were investigated on single skinned fibers. Sarcomeres of woody breast fibers were more compliant, which is very likely related to the wider spacing (18% wider compared to controls) between thick and thin filament. No differences were found in optimal sarcomere length (2.68 +/- 0.04 vs. 2.65 +/- 0.05 mu m) nor in maximal active stress (116 +/- 17 vs. 125 +/- 19 mN mm(-2)). However, woody breast fibers had less steep descending arm as shown in length-tension curve. Woody breast muscle fibers had 40% bigger sarcomeric volume compared to controls. Content of contractile proteins (myosin and actin), and maximal shortening velocity were unchanged indicating that the growth in woody breast muscle fiber was associated with synthesis of new contractile units with unaltered kinetics. Calcium sensitivity was decreased in woody breast muscle fibers significantly. In conclusion, the results show that the rapid growth of muscle in woody breast disease is associated with significant structural and functional changes in the pectoralis major musculature, associated with alterations in the mechanical anchoring of contractile filaments.
  • Zhang, Yuemei; Ertbjerg, Per (2018)
    This study aimed to determine the effect of frozen-then-chilled storage on free Ca2+, proteolytic enzyme activity of calpains and the proteasome, water-holding capacity and shear force of porcine longissimus thoracis et lumborum muscle. Pork loins were subjected to either chilled storage at 2 +/- 1 degrees C for 1, 2, 4, 6 and 9 days, or frozen then chilled storage (20 +/- 1 degrees C for 1 week followed by thawing overnight). Free Ca2+ increased with chilled storage in the non-frozen group. Frozen-then-chilled storage increased free Ca2+ concentration, followed by a faster decrease of calpain-1 activity and activation of around 50% of calpain-2. Proteasome activity was reduced by around 40% following freezing-thawing. Purge loss increased and water-holding capacity of myofibrils decreased in the frozen-thawed group, suggesting considerable denaturation of myofibrillar proteins. Shear force was not affected by freezing-thawing, and we speculate that the tenderizing effect of calpain activation was counteracted by loss of proteasome activity and substantial exudate loss.
  • Ylä-Ajos, Maria; Tuominen, Satu; Hänninen, Laura; Ruusunen, Marita; Puolanne, Eero; Valros, Anna (2012)
    1. Investigations were made into the breast and leg muscle energy metabolism, and the quality of breast meat of turkeys after controlled atmosphere stunning or stun-killing (CAS) with various gas mixtures. In addition, the effect on meat quality of an increase in the chilling rate of turkey breast meat after hypercapnic or anoxic stun-killing was studied. 2. A total of 35 turkey toms within two replicate pens were individually stunned during consecutive weeks using one of 4 CAS methods. The stunning gases tested were high CO2 concentration (60% CO2 in air), high N2 concentration (98% N2, 2% O2), a mixture of 76% N2 and 24% CO2, and a biphasic method (first minute in mixture containing 40% CO2, 30% N2, and 30% O2; followed by two minutes in a mixture containing 60% CO2 in air). 3. The birds stunned with N2 displayed the highest initial reduction in muscle pH, but after 4 h post mortem there were no differences in pH values associated with the various CAS methods. 4. The CAS method alone had no statistically significant effect on the quality of turkey breast muscle when the chilling speed was rapid (0°C for 4 h, followed by storage at 4°C). When the chilling rate was slowed (20°C for4 h followed by storage at 4°C), a significant decrease in cooking loss and in Warner-Bratzler shear force was recorded for birds stun-killed with CO2. 5. This study shows that anoxic stun-killing with N2 had no adverse effects on meat quality despite the rapid post mortem pH decrease. The CAS with N2 allows rapid cooling of carcases without the risk of cold shortening, whereas with CO2-stun-killing of turkeys, the rate of chilling should be slower. Concerning meat quality, all the CAS methods tested were suitable for stunning turkeys.
  • Huuskonen, Arto; Jaakkola, Seija; Manni, Katariina (2020)
    Total mixed rations (TMR) based on grass silage (GS), triticale silage (TS), mixture of GS and TS, barley silage (BS) and mixture of GS and BS were fed to fifty Hereford (HF) and fifty Charolais (CH) bulls. The proportion (g kg(-1) dry matter [DM]) of the silages in the TMRs were as follows: (1) GS (600); (2) TS (600); (3) GS (300) and TS (300); (4) BS (600); (5) GS (300) and BS (300). Concentrate proportion was 400 g kg(-1) DM. According to feed analyses, the GS had 15 and 8% higher metabolizable energy (ME) concentration as well as 51 and 49% higher crude protein (CP) concentration compared to TS and BS, respectively. Average DM intake (DMI) on TS and BS containing diets was higher compared to GS as a sole forage (p=0.001). Compared to the TS based rations the use of BS rations increased daily DMI by 5% (p
  • Wang, Ying; Yang, Yang; He, Jun; Cao, Jinxuan; Wang, Hongfei; Ertbjerg, Per (2020)
    The objective was to characterize the effect of wooden breast (WB) myodegeneration on the metabolite profile of chicken meat by H-1 NMR and multivariate data analysis. The results displayed that the metabonome of chicken breast consisted predominantly of 30 metabolites, including amino acids, organic acids, carbohydrates, alkaloids, nucleosides and their derivatives. WB-affected samples showed higher leucine, valine, alanine, glutamate, lysine, lactate, succinate, taurine, glucose, and 5'-IMP levels, but lower histidine, beta-alanine, acetate, creatine, creatinine, anserine and nicotinamide adenine dinucleotide levels compared to normal fillets (p <0.05). In conclusion, results indicated that WB-affected fillets possessed a unique biochemical signature. This unique profile could identify candidate biomarkers for diagnostic utilization and provide mechanistic insight into biochemical processes leading to WB myopathy in commercial broiler chickens.
  • Zhang, Yuemei; Ertbjerg, Per (2019)
    The role of protein denaturation in formation of thaw loss is currently not well understood. This study investigated denaturation of myofibrillar and sarcoplasmic proteins of pork loins caused by freezing-thawing in relation to freezing rate. Compared to fast freezing, slow freezing caused 28% larger thaw loss, decreased water-holding capacity of myofibrils and increased surface hydrophobicity, indicating more pronounced denaturation of myofibrillar proteins. We here propose a model: In slow freezing protons are concentrated in the unfrozen water resulting in reduced pH in proximity of structural proteins causing protein denaturation. In parallel, large ice crystals are formed outside of muscle fibers resulting in transversal shrinkage. In fast freezing small ice crystals trap protons and cause less severe protein denaturation and reduced thaw loss. Differential scanning calorimetry and tryptophan fluorescence spectra indicated sarcoplasmic protein denaturation in drip due to freezing-thawing. However, sarcoplasmic protein denaturation was independent of freezing rate.
  • Brink, C. W.; Santangeli, A.; Amar, A.; Wolter, K.; Tate, G.; Krüger, S.; Tucker, A. S.; Thomson, R. L. (2020)
    Old world vultures are the most threatened group of raptors globally. Supplementary feeding sites (SFS) are a popular conservation tool, widely used to assist vulture populations. Despite their popularity, the impact of SFS on vultures remains largely unstudied. A lack of knowledge on the number, distribution and management of SFS is a key factor hindering such research. In this study, we compile records of SFS in South Africa and conduct questionnaires with SFS managers to characterize SFS. We identify 143 currently active SFS. Our data suggest that SFS numbers have been stable over the last decade. The average provisioning rate for all SFS was 64.6 kg day(-1). Overall SFS provide an estimated 3301 tonnes of food to scavengers each year, the equivalent of 83% of the energetic needs of all vultures in the region. This contribution was highly skewed, however, with just 17% of active SFS sites providing 69% of all food. Furthermore, these resources were not equally distributed, with SFS in Limpopo, North West and Kwazulu-Natal provinces providing 83% of the total meat provisioned. The three most common meat types provided at SFS were beef (39%), pork (33%) and game (19%). Worryingly, we found that 68% and 28% of SFS managers were unaware of the potential harmful effects of lead and veterinary drugs, respectively, which highlights potential poisoning risks associated with SFS. Examining exposure to SFS by different vulture species, we found that whilst SFS are accessible across the distribution range of vultures with large home ranges (e.g. African white-backed and Cape vultures), those species with smaller home ranges have relatively poor accessibility. With this study, we demonstrate the potential importance, but also associated risks, of SFS to vultures in South Africa, and provide the information base to assess the impacts of this popular but as yet largely unassessed conservation tool.
  • Zhang, Yuemei; Kim, Y. H. B.; Puolanne, Eero; Ertbjerg, Per (2022)
    Formation of thaw loss cannot generally be avoided when meat is frozen and then thawed. Explanations have mainly focused on the damage to muscle fibers resulting from ice crystallization and the freezing-induced denaturation of myofibrillar proteins, the latter of which has, however, not received much research focus. This review discusses the relationship between myofibrillar protein denaturation and water-holding capacity of meat in freezing-thawing with the aim to improve the understanding the relative importance of protein denaturation in the formation of thaw loss. The contribution of decreased pH and high ionic strength in the unfrozen water in freezing is emphasized and we hypothesize that these two factors are causing protein denaturation and conformational changes within muscle fibers, and consequently loss of water-holding capacity. Slow freezing produces more thaw loss than fast freezing, and this is discussed here in relation to the impacts on myofibrillar protein denaturation induced by the freezing rate.
  • EFSA Panel on Animal Health and Welfare (AHAW); Nielsen, Søren Saxmose; Alvarez, Julio; Bicout, Dominique Joseph (2019)
    The killing of poultry for human consumption (slaughtering) can take place in a slaughterhouse or during on-farm slaughter. The processes of slaughtering that were assessed, from the arrival of birds in containers until their death, were grouped into three main phases: pre-stunning (including arrival, unloading of containers from the truck, lairage, handling/removing of birds from containers); stunning (including restraint); and bleeding (including bleeding following stunning and bleeding during slaughter without stunning). Stunning methods were grouped into three categories: electrical, controlled modified atmosphere and mechanical. In total, 35 hazards were identified and characterised, most of them related to stunning and bleeding. Staff were identified as the origin of 29 hazards, and 28 hazards were attributed to the lack of appropriate skill sets needed to perform tasks or to fatigue. Corrective and preventive measures were assessed: measures to correct hazards were identified for 11 hazards, with management shown to have a crucial role in prevention. Ten welfare consequences, the birds can be exposed to during slaughter, were identified: consciousness, heat stress, cold stress, prolonged thirst, prolonged hunger, restriction of movements, pain, fear, distress and respiratory distress. Welfare consequences and relevant animal-based measures were described. Outcome tables linking hazards, welfare consequences, animal-based measures, origins, and preventive and corrective measures were developed for each process. Mitigation measures to minimise welfare consequences were also proposed. (C) 2019 European Food Safety Authority. EFSA Journal published by John Wiley and Sons Ltd on behalf of European Food Safety Authority.
  • EFSA Panel Anim Hlth Welf AHAW; Nielsen, Soren Saxmose; Sihvonen, Liisa Helena (2020)
    This opinion on the killing of rabbits for human consumption ('slaughtering') responds to two mandates: one from the European Parliament (EP) and the other from the European Commission. The opinion describes stunning methods for rabbits known to the experts in the EFSA working group, which can be used in commercial practice, and which are sufficiently described in scientific and technical literature for the development of an opinion. These are electrical stunning, mechanical stunning with a penetrative and non-penetrative captive bolt and gas stunning. The latter method is not allowed in the EU anymore following Council Regulation (EC) No 1099/2009, but may still be practiced elsewhere in the world. Related hazards and welfare consequences are also evaluated. To monitor stunning effectiveness as requested by the EP mandate, the opinion suggests the use of indicators for the state of consciousness, selected on the basis of their sensitivity, specificity and ease of use. Similarly, it suggests indicators to confirm animals are dead before dressing. For the European Commission mandate, slaughter processes were assessed from the arrival of rabbits in containers until their death, and grouped in three main phases: pre-stunning (including arrival, unloading of containers from the truck, lairage, handling/removing of rabbits from containers), stunning (including restraint) and bleeding (including bleeding following stunning and bleeding during slaughter without stunning). Ten welfare consequences resulting from the hazards that rabbits can be exposed to during slaughter are identified: consciousness, animal not dead, thermal stress (heat or cold stress), prolonged thirst, prolonged hunger, restriction of movements, pain, fear, distress and respiratory distress. Welfare consequences and relevant animal-based measures (indicators) are described. Outcome tables linking hazards, welfare consequences, indicators, origins, preventive and corrective measures are developed for each process. Mitigation measures to minimise welfare consequences are also proposed. (C) 2020 European Food Safety Authority. EFSA Journal published by John Wiley and Sons Ltd on behalf of European Food Safety Authority.
  • Koivunen, Erja; Talvio, Eija; Valkonen, Eija; Tupasela, Tuomo; Tuunainen, Petra; Valaja, Jarmo (2016)
    The aim was to study the effects of dietary pea inclusion and the addition of Avizyme 1200 -enzyme cocktail on broiler performance, intestinal viscosity and organoleptic quality of meat. The experimental design was a 4 x 2 factorial, the factors being dietary pea inclusion (0, 150, 300 and 450 g kg(-1)) in the diets fed from day 9 to day 38 and the addition of Avizyme 1200 enzyme cocktail including amylase, protease and xylanase during the entire experiment. The growth of birds improved (p 0.05). In conclusion, 450 g kg(-1) peas can be used in the broiler grower diets without negative effects on the bird performance. The use of enzyme cocktail improves bird performance.
  • EFSA Panel Anim Hlth Welf AHAW; Nielsen, Soren Saxmose; Velarde, Antonio (2020)
    Pigs at different stages of the production cycle may have to be killed on-farm for purposes other than slaughter (where slaughter is defined as killing for human consumption) either individually (e.g. severely injured pigs) or on a large scale (e.g. unproductive animals or for disease control reasons). This opinion assessed the risks associated with the on-farm killing of pigs and included two phases: 1) handling and moving of pigs and 2) killing methods (including restraint). The killing methods were subdivided into four categories: electrical methods, mechanical methods, gas mixture methods and lethal injection. Four welfare consequences to which pigs can be exposed to during on-farm killing were identified: pain, fear, impeded movement and respiratory distress. Welfare consequences and relevant animal-based measures were described. In total, 28 hazards were associated with the welfare consequences; majority of the hazards (24) are related to Phase 2 (killing). The main hazards are associated with lack of staff skills and training, and poor-designed and constructed facilities. Staff was identified as an origin of all hazards, either due to lack of skills needed to perform appropriate killing or due to fatigue. Corrective measures were identified for 25 hazards. Outcome tables linking hazards, welfare consequences, animal-based measures, hazard origins, preventive and corrective measures were developed and mitigation measures proposed. (C) 2020 European Food Safety Authority. EFSA Journal published by John Wiley and Sons Ltd on behalf of European Food Safety Authority.
  • Norring, M.; Valros, A.; Valaja, J.; Sihvo, H-K; Immonen, K.; Puolanne, E. (2019)
    Wooden breast myopathy, a condition where broiler breast muscles show a hardened consistency post-mortem, has been described recently. However, it is not known how wooden breast myopathy affects the bird activity or welfare. Altogether, over 340 birds of five commonly used commercial hybrids were housed in 25 pens, and sample birds killed at ages of 22, 32, 36, 39 and 43 days. Their breast muscle condition was assessed post-mortem by palpation. The birds were gait scored and their latency to lie was measured before killing. For further behavior observations, one affected and healthy bird in 12 pens were followed on 5 days for 20 minutes using video recordings. The connection of myopathy to gait score and activity was analyzed with mixed models. A higher gait score of wooden-breast-affected birds than that of unaffected birds (2.9 +/- 0.1 v. 2.6 +/- 0.1, P <0.05) indicated a higher level of locomotor difficulties over all age groups. The wooden-breast-affected birds had fewer crawling or movement bouts while lying down compared with unaffected (P <0.05). Wooden breast myopathy-affected birds were heavier (2774 +/- 91 v. 2620 +/- 91 g; P <0.05) and had higher breast muscle yield (21 +/- 1 v. 19 +/- 1%; P <0.05) than unaffected birds overall. Older birds had longer lying bouts, longer total lying time, fewer walking bouts, more difficulties to walk and to stand compared with younger birds (P <0.05). Birds with poorer gait had longer total lying time and fewer walking bouts (P <0.05). Birds with greatest breast muscle yield had the largest number of lying bouts (P <0.05). It was concluded that wooden breast myopathy was associated with an impairment of gait scores, and may thus be partly linked to the common walking abnormalities in broilers.