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OBJECTIVE: The objective of this study was to evaluate three different degrees of white striping (WS) addressing their automatic assessment and customer acceptance. The WS classification was performed based on a computer vision system (CVS), exploring different machine learning (ML) algorithms and the most important image features. Moreover, it was verified by consumer acceptance and purchase intent. METHODS: The samples for image analysis were classified by trained specialists, according to severity degrees regarding visual and firmness aspects. Samples were obtained with a digital camera, and 25 features were extracted from these images. ML algorithms were applied aiming to induce a model capable of classifying the samples into three severity degrees. In addition, two sensory analyses were performed: 75 samples properly grilled were used for the first sensory test, and 9 photos for the second. All tests were performed using a 10-cm hybrid hedonic scale (acceptance test) and a 5-point scale (purchase intention). RESULTS: The information gain metric ranked 13 attributes. However, just one type of image feature was not enough to describe the phenomenon. The classification models support vector machine, fuzzy-W, and random forest showed the best results with similar general accuracy (86.4%). The worst performance was obtained by multilayer perceptron (70.9%) with the high error rate in normal (NORM) sample predictions. The sensory analysis of acceptance verified that WS myopathy negatively affects the texture of the broiler breast fillets when grilled and the appearance attribute of the raw samples, which influenced the purchase intention scores of raw samples. CONCLUSION: The proposed system has proved to be adequate (fast and accurate) for the classification of WS samples. The sensory analysis of acceptance showed that WS myopathy negatively affects the tenderness of the broiler breast fillets when grilled, while the appearance attribute of the raw samples eventually influenced purchase intentions.

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Abstract The aim of this work was to study the myofibril proteins and collagen fraction changes in broiler chickens PSE (pale, soft, exudative) meat during ageing and their relationship to meat quality. The results presented an increase of myofibril proteins and collagen solubility promoted by the enhanced proteases activities during storage. Ultramicroscopically, the PSE meat samples revealed intracellularly a sarcomere super contraction and lacunas within the A and I bands while Z-lines appeared very dense and fragmented in comparison to normal samples. This observation was noticed already at 4h storage while extracellularly collagen fibrils decreased visually within the endomysium only after 24h of conditioning. These results influenced the quality as the PSE meat presented better functional properties at the first hours of conditioning before further proteins degradation by proteases. Thereafter, at the later ageing stage a further disintegration of the abnormal meat structure would affect the meat functional properties.

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This study evaluated the formed microclimate commercial truck transport practices effects on the turkeys' welfare by measuring Dead on Arrival (DOA) index and pale, soft, and exudative (PSE-like) meat occurrence. The experimental design was entirely randomized in a 6 × 2 factorial arrangements (two truck container compartments × six water shower groups) with birds positioned at superior front (SF), inferior front (IF), superior middle (SM), inferior middle (IM), superior rear (SR), and inferior rear (IR) and two bath treatments: with water shower (WiS) and without water shower (WoS) with eight replications for each treatment. The animals were transported for 95 min' journey from the farm to the slaughterhouse under hot-humidity conditions. The results shown herein indicated the formation of a thermal core at the inferior middle and rear truck container regions, because the heat produced by the birds and the influence of developed microclimate consisting of temperature, relative humidity, and air ventilation. The IM and IR container compartments under the WoS treatment presented the highest (P < 0.01) numbers of PSE-like meat incidence and DOA index values compared with those located at the front under WiS treatment as the consequence of the altered to birds unbearable conditions within the container microclimate in transit. The formed microclimate during the commercial transport practices under hot-humidity conditions affected the bird's welfare consequently turkey meat qualities.

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ABSTRACT The objective of this study was to determine the incidence of Pale, Soft, Exudative (PSE) meat and to characterize the Dark, Fim, Dry (DFD) meat as well as the Dead on Arrival (DOA) index in a commercial turkey slaughterhouse in southern Brazil during the summer and winter seasons. The journeys (n=64) were over a distance of 36 ± 20 km and took approximately 95 ± 20 min. Color (L*) and pH distribution of turkey breast meat (n=5,352) were evaluated from different farms (n=64) during the 2015-2016 years. The pH, water-holding capacity, color (L*, a*, b*) were used to establish cutoff values for DFD meat (L* < 44.0 and pH > 5.90) and presented correlation among them. The L* value was the highest during the summer (P<0.01), indicating the highest incidence of PSE meat (28.35 %), and lowest during winter, observing the highest incidence of DFD meat (10.3 %). Finally, the obtained summer DOA index was 0.23 % higher in relation to winter.

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The connections between the redox imbalance in post-mortem muscle, early protein oxidation and the onset of pale, soft and exudative (PSE) condition in chicken breast are studied. PSE was induced by incubation of post-mortem chicken carcasses at 37°C for 200min. PSE-induced muscle consistently had faster pH decline and lower pH at 200min (5.84 vs. 6.59) and 24h (5.69 vs. 5.96), higher L(∗) (54.4 vs. 57.3), and lower texture and water holding capacity (WHC) than normal meat. The activities of catalase, glutathione peroxidase and superoxide dismutase were significantly lower in PSE-induced samples than in the normal counterparts. PSE was more susceptible to proteolysis and protein oxidation than normal meat during succeeding chilled storage with more intense tryptophan and thiols depletion, higher protein carbonylation and more intense formation of protein cross-links. We provide plausible explanations to support the role of protein oxidation in the impaired quality PSE chicken.

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Throughout the chicken production chain, transport from farm to the commercial abattoir is one of the most critical sources of stress, particularly heat stress. The aim of this work was to describe the performance of a new prototype truck container designed to improve the microenvironment and reduce the incidence of pale, soft and exudative (PSE) meat and dead on arrival (DOA) occurrences. Experiments were carried out for four different conditions: regular and prototype truck, both with and without wetting loaded cages at the farm (for bird thermal stress relief) just before transporting. While there was no difference in the DOA index (P ≥ 0.05), the prototype truck caused a reduction (P < 0.05) in the occurrence of PSE meat by 66.3% and 49.6% with and without wetting, respectively. The results of this experiment clearly revealed a low-cost solution for transporting chickens that yields better animal welfare conditions and improves meat quality.

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The aim of this work was to evaluate pH values fall rate in chicken breast meat under commercial refrigeration processing conditions and the development of PSE (pale, soft, exudative) meat. Broiler breast samples from the Cobb breed, both genders, at 47 days of age (n = 100) were taken from refrigerated carcasses (RS) immersed in water and ice in a tank chilled at 0°C (±2). pH and temperature (T) values were recorded at several periods throughout refrigeration in comparison to samples left at room T as control (CS). The ultimate pH (pHu) value of 5.86 for RS carcasses were only reached at 11°C after 8.35 h post mortem (PM) while, for CS samples, pHu value was 5.94 at 22°C after 4.08 h PM. Thus, under commercial refrigeration conditions, the glycolysis rate was retarded by over 4.0 h PM and the breast meat color was affected. At 24.02 h PM, PSE meat incidence was 30% while for CS, meat remained dark and PSE meat was not detected. Results show retardation in the glycolysis rate and PSE meat development was promoted by the refrigeration treatment when compared with samples stored at processing room temperature.

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Meat production with minimum animal suffering is a humanitarian concern. Thus, the objective of this work was to observe the performance of Cobb broiler chickens from 7 to 46 days of age when raised under different installations: dark house system (DHS), conventional yellow system (CYC) and conventional blue system (CBC). The feed conversion ratio for the birds raised on the DHS was 3.8% and 2.7% lower than those for the CYC and CBC systems, respectively. Compared with the CYC and CBC systems, average daily gain under the DHS was 11.4% and 9.3% higher, respectively, and body weight at 46 days was 11.4% and 9.3% higher, respectively (P ≤ 0.05). The birds' welfare was assessed based on their stress by determining the amount of pale, soft and exudative (PSE) meat in the breast fillets. The CYC and CBC birds had 24.3% and 25.3% PSE meat, respectively, whereas the DHS birds had 37.0%. We concluded that the DHS has a greater potential to produce broiler chickens, with superior performance to conventional systems, despite the higher stress faced by the birds during the maneuvers just before slaughter.

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This study evaluated alternative methods for extracting collagen from the tunica albuginea of pig testes and characterized the functional properties of the isolated collagen. Using the statistical tools of factorial design (24⁻¹) and a central composite rotatable design (2³), it was concluded that the best conditions were 0.83 mol L⁻¹ acetic acid, 0.24% pepsin and 28 h of hydrolysis to isolate 82.54 g of collagen per 100g of sample. This purified collagen had improved functional properties in relation to bovine skin collagen, including water solubility, water-holding capacity, emulsifying capacity and emulsion stability. These results suggest that isolated collagen from the tunica albuginea can be used in pharmaceutical and food products.

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The objective of this work was to investigate the relationship between poultry PSE meat and water loss of frozen chicken carcass in two experiments. The first experiment was carried out in commercial abattoir. Poultry carcass were classified as PSE meat (n=59) (pH <5.8) and control samples (n=55) (pH >5.8). Water absorption and drip test were performed according to the Brazilian legislation methodologies. The second experiment was carried out with commercial whole five brands frozen carcasses purchased from the local supermarkets (n=30) and analyzed for pH, water holding capacity (WHC) and drip test. PSE poultry meats absorbed 3.59% of water during the processing similar to the control samples; however, released 0.38% more water during thawing of the carcasses. From these five brands evaluated, three presented drip values above 6.0%. The highest drip value was showed by the brand sample that had pH and WHC values characteristics of PSE meat. It could be postulated that PSE meat phenomenon promoted more water release during thawing leading to a misinterpretation in relation to the Brazilian legislation for water carcass liberation during thawing.

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The objective of this work was to study the effect of blue light diffuser on the broiler stress control by measuring the occurrence of PSE meat just before slaughtering. Birds were divided into the following two groups before slaughter at the point of being hung on shackles: broiler group under low intensity blue light ambience (475, 17-20 lx) and control group under white light (550-650nm, 321-332 lx). Birds' stressful conditions were measured by the occurrence of PSE meat. Breast fillets were classified as PSE meat based on pH (<5.8) and lightness (L*> 53.0). The fillet samples in the control group had the following characteristics: pHu=5.77, L* = 54.26 and b*= 6.27. The fillet samples from birds under blue light ambience had the following characteristics: pHu=5.81, L* = 52.86 and b* = 5.22 (p < 0.05). These results revealed that the treatment of blue light ambience just before slaughtering contributed to the alleviation of ante mortem stress of the birds, which was observed by a 14% decrease in the occurrence of PSE meat. Exposure to blue light just before slaughtering was shown to have potential to be used in modern slaughterhouses to offer a comfortable atmosphere, thereby maintaining breast meat quality.

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The objective of this work was to evaluate the application of carrageenan (CAR) to improve the functional properties of the jerked beef (JF) and to increase its processing yield. JB produced from Vastus lateralis with CAR (1.0%) at 25ºC and NaCl (15.0%) had approximately 15.0% higher moisture and a 32.0% higher processing yield in comparison to the control samples.JB-CAR presented shear force approximately 5.0 and 20% lower in the samples uncooked salted and desalted cooked, respectively, and sensorial acceptance above 80%. The results demonstrated the possibility of applying carrageenan to jerked beef in order to obtain an increase in the processing yield and a tender product while maintaining the sensorial quality and its intermediate-moisture meat product nature.

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In this study, the changes in the lipid (Lox) and protein oxidation (Pox) were measured quantitatively by TBARS and carbonyl methods, respectively, throughout the salting and drying steps of charqui meat (CH) and jerked beef (JB) preparation and their storage up to 60 days. The experiment was carried out on CH samples treated with brine (20.0%) and JB with same brine solution added with sodium nitrite (0.02%). After 60 days of storage, the carbonyl substances in CH were 2.77nmol mg-1 while in the JB samples, there was 61.0% oxidation inhibition. The TBARS determination revealed a Lox inhibition by approximately 5-fold in the latter samples. These results indicated that in the metmyoglobin molecule, the nitrite kept the Fe in the Fe2+ state in JB samples whereas in CH, the Fe was oxidized to Fe3+, which catalyzed the oxidation reactions more efficiently, leading to the higher development of Lox and Pox.

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O objetivo deste trabalho foi revisar as aplicações tecnológicas e alternativas para redução do uso de cloreto de sódio em produtos cárneos. Foram abordadas as características do consumo de cloreto de sódio, destacando sua ação hipertensiva, as aplicações tecnológicas do cloreto de sódio em produtos cárneos, incluindo a promoção do gosto salgado, seu efeito sobre a atividade de água e a estabilidade microbiológica, além da sua influência nas propriedades funcionais das proteínas cárneas. Também foram apontados os métodos disponíveis para redução dos níveis de NaCl nos derivados cárneos, como o uso de sais não sódicos, novos ingredientes e métodos de conservação alternativos. A preocupação dos consumidores relacionada aos efeitos prejudiciais à saúde, associada ao consumo excessivo de sódio, exigirá das indústrias alimentícias continua redução do uso de sal nos alimentos. Essa limitação enfrenta maior complexidade no segmento cárneo, pois além de prover palatabilidade, o NaCl é responsável por diversas propriedades funcionais. A busca de alternativas para redução do uso de NaCl, sem prejuízo para a qualidade sensorial dos produtos, constitui desafio a ser enfrentado pela indústria, visando manter a aceitação e consumo dos derivados cárneos.

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The excessive release of calcium from the sarcoplasmic reticulum during the installation of PSE (Pale, Soft, Exudative) meat, leads to increase of phospholipase A2 (PLA2) activity and consequently causes a higher lipid oxidation. In contrast, glutathione peroxidase (GSH-Px) is a selenium-dependent antioxidant enzyme that prevents the oxidative damage. The aim of this work was to investigate the secreted PLA2 (sPLA2) and GSH-PX activities in PSE poultry meat. Breast meat samples (Pectoralis major m.) (n=24) were obtained from commercial slaughterhouse. Samples were classified as PSE and Control Meat based on pH and L* values, fillets with pH1h30? 6.0 and L24h* ?53.0 as PSE and fillets with pH1h30> 6.0 and L24h* 53.0 with Control. sPLA2 was analyzed using enzymatic assay kit and GSH-Px was measured a coupled assay procedure recording the NADPH (nicotinamide adenine dinucleotide phosphate reduced) oxidation. The sPLA2 average was 0.295 Umg-1 of protein for PSE meat and 0.380 Umg-1 of protein for Control meat, did not differ significantly (p >0,05). The GSH-Px activity was approximately 24,4% higher (p?0,05) for Control meat when compared to PSE meat. The sPLA2 activity of PSE fillets did not changed, however PSE fillets present the enzymatic system of antioxidant defense compromised with lower GSH-PX activity.

A liberação excessiva de cálcio do retículo sarcoplasmático durante a instalação de carnes PSE (Pale, Soft, Exudative) leva a um aumento da atividade da fosfolipase A2 (PLA2), promovendo uma maior oxidação lipídica. Por outro lado, a glutationa peroxidase (GSH-Px) é uma enzima antioxidante selênio dependente, prevenindo danos oxidativos. O objetivo deste trabalho foi investigar as atividades da PLA2 secretada (sPLA2) e da GSH-PX em filés PSE de frango. Filés de frango (Pectoralis major m.) (n=24) foram obtidos de um frigorífico comercial. As amostras foram classificadas em PSE e Controle, com base nos valores de pH e L*, filés com pH1h30 ? 6.0 e L24h* ? 53,0 como PSE e filés com pH1h30> 6,0 e L24h* 53,0 como Controle. A atividade da sPLA2 foi determinada por kit enzimático e a atividade da GSH-Px foi determinada pela oxidação do NADPH (Nicotinamida Adenina Dinucleotídeo Fosfato Reduzido). A atividade média da sPLA2 foi de 0,295 U.mg-1 de proteína para os filés PSE e de 0,380 U.mg-1 de proteína para os filés do Controle, não apresentado diferenças significativas (p >0,05). A atividade da GSH-Px foi aproximadamente 24,4% maior (p?0,05) para os filés Controle quando comparado com filés PSE. A atividade da sPLA2 em filés PSE não foi alterada, entretanto filés PSE apresentam o sistema enzimático de defesa antioxidante comprometido com menor atividade de GSH-Px.

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The glutathione peroxidase (GSH-Px) is selenium-containing enzyme, which catalyses the reduction of hydrogen peroxides and lipid hydroperoxides preventing the oxidative damages in animal tissues. The selenium (Se) deficiency increases the need for vitamin E. The aim of this study was to investigate the effect of dietary supplementation of chelated Se on the poultry meat quality. Fourteen Cobb chicks with 1 day of age were divided into two groups: C-Control group (without supplementation) and S-Supplemented group (with 0.03mg of chelated Se.kg-1 of feed). Birds at 42 days of age were slaughtered and boneless skinless chicken thighs were collected and stored at 18ºC for 30 days. Thighs were analyzed for the cooking loss, lipid oxidation by Thiobarbituric-Acid-Reactive Substances (TBARS) and GSH-Px activity by coupled assay procedure recording the NADPH (nicotinamide adenine dinucleotide phosphate reduced) oxidation. Samples of Supplemented group presented 33.8% less water after cooking (p ? 0.05) and were 23.6% (p ? 0.10) less oxidized when compared with samples of group Control. The GSH-Px activity of thighs did not differ significantly (p> 0.05) between groups Supplemented and Control. The supplementation with 0.03mg of Se in the kg of feed improved the meat quality by reducing the lipid oxidation and cooking loss, however did not increase the GSH-Px activity.

O selênio (Se) é componente da enzima glutationa peroxidase (GSH-Px) que catalisa a redução de peróxido de hidrogênio e peróxido lipídico, prevenindo danos oxidativos nos tecidos animais. A deficiência de Se aumenta a necessidade de vitamina E pelos animais. O objetivo deste trabalho foi avaliar o efeito da suplementação de selênio quelatado sobre a qualidade da carne de frango. Os 14 pintinhos de corte da linhagem Cobb de 1 dia de idade foram divididos em 2 grupos: C-Controle (sem suplementação) e S-Suplementado com 0,03mg Se quelatado. kg-1 de ração. Os frangos com 42 dias de idade foram abatidos e as sobrecoxas desossadas foram coletadas e armazenadas por 30 dias a 18C. As sobrecoxas foram avaliadas quanto a perda por cozimento (PPC), oxidação lipídica pelo método de Substâncias Reativas ao Ácido Tiobarbitúrico (TBARS) e atividade da enzima GSH-Px pela oxidação do NADPH (Nicotinamida Adenina Dinucleotídeo Fosfato Reduzido). As sobrecoxas de frangos do grupo Suplementado perderam 33,8% menos de água após cozimento (p?0,05) e apresentaram-se 23,6% menos oxidadas (p?0,10) quando comparadas com as sobrecoxas do grupo Controle. A atividade da GSH-Px das sobrecoxas não diferiu significativamente (p>0,05) entre os grupos Suplementado e Controle. A suplementação com 0,03mg de selênio quelatado por kg de ração promoveu melhora na qualidade da carne com redução na PPC e na oxidaç

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This research was aimed at assessing parameters such like productive and meat quality characteristics of broilers fed on diets with different levels of organic selenium (0; 0,2; 0,4 e 0;6 mg Se/kg of feed). Three hundred male one-day old chickens have been submitted to a completely randomized design, with five repetitions of 15 birds per experimental parcel. Characteristics such like performance, yield grade, cuts, and meat quality have been assessed. The results revealed that the supplementation with selenium did not affect productive characteristics of the broilers. However, it produced a linear reduction on the abdominal fat of the carcasses assessed. Regarding meat quality, the supplementation with organic selenium linearly increased the pH levels at the breast. Besides, it linearly reduced the loss of water by pressure and the shear force, which in turn improved the final quality of the meat.

O trabalho teve como objetivo avaliar as características produtivas, de rendimento e qualidade de carne de frangos de corte alimentados com dietas suplementadas com diferentes níveis de selênio orgânico (0; 0,2; 0,4 e 0,6 mg Se/kg de ração). Foram utilizados 300 pintainhos de corte machos, da linhagem Cobb, com um dia de idade. Foi adotado um delineamento inteiramente ao acaso, com quatro tratamentos (níveis de selênio orgânico), com cinco repetições de 15 aves por parcela experimental. Foram avaliados o desempenho, rendimento de carcaça e cortes e a qualidade de carne de frangos de corte. Os resultados de desempenho mostram que a suplementação de selênio não alterou os dados produtivos, porém, reduziu linearmente a gordura abdominal da carcaça. Quanto à qualidade de carne, a suplementação de selênio orgânico aumentou linearmente o pH da carne do peito e reduziu a perda de água por pressão e a força de cisalhamento, melhorando assim a qualidade da carne das aves.

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Porcine Stress Syndrome (PSS) is a syndrome that occurs in pigs. PSS animals are sensitive to the anesthetic halothane, have higher activities of Creatine Kinase (CK) and Lactate Dehydrogenase (LDH) and are predisposed to the development of PSE (Pale, Soft, Exudative) meat, compromising the meat quality. In chickens, little is known about the relationship between sensitivity to and halothane changes in the activities of these enzymes with the occurrence of PSE meat. The aim of this study was to evaluate the CK and LDH activities in sensitive and non-sensitive halothane chickens and for stress susceptibility identification and PSE meat development. Birds were exposed to halothane at a 3.0 % concentration in pure O2 for 5 min. Afterwords, they were classified into groups: sensitive to halothane (HAL +) (stiffening of the lower limbs) and Non-sensitive (HAL-) (no hardening). After 3 h and 48 h to the test, blood was collected from the wing vein gill, serum extracted and stored at 22 C until analysis of CK and LDH. No differences were observed (p ? 0.05) in CK activity for HAL+ and HAL- groups. However, differences (p ? 0.05) were observed the LDH activity at 3 h and 48 h, and 44.2 % and 66.1 % higher for the group HAL +, respectively. The determination of lactate dehydrogenase activity indicates to be an alternative to identify animals susceptible to stress thus prone to produce

PSS do inglês Pork Stress Syndrome (Síndrome do Estresse Suíno) é uma anormalidade que ocorre em suínos. Animais PSS são sensíveis ao anestésico halotano, apresentam maior atividade das enzimas Creatina Quinase (CK) e Lactato Desidrogenase (LDH) e são predispostos ao desenvolvimento de carnes PSE (Pale, Soft, Exudative), comprometendo sua qualidade. Em frangos, pouco se conhece sobre a relação entre a sensibilidade ao halotano e alterações nas atividades destas enzimas com a ocorrência de carnes PSE. O objetivo deste trabalho foi determinar as atividades das enzimas CK e LDH em frangos sensíveis e não sensíveis ao halotano para identificação da susceptibilidade ao estresse e ao desenvolvimento de carnes PSE. As aves foram expostas ao halotano na concentração de 3,0% em oxigênio puro por 5 min. Posteriormente, foram classificadas como sensível ao halotano (HAL+), quando ocorreu o enrijecimento dos membros inferiores e não sensível (HAL-), quando houve ausência de enrijecimento. Após 3 h e 48 h da realização do teste de sensibilidade ao halotano, o sangue foi coletado da veia branquial da asa e o soro foi extraído e armazenado à 22 ºC até as determinações das atividades de CK e LDH. Não foram observadas diferenças (p?0,05) na atividade de CK entre os frangos HAL+ e HAL-. Entretanto, diferenças (p?0,05) foram verificadas nas atividades de LDH nos tempos de 3 h e 48 h, sendo 44,2%

RESUMEN

The excessive release of calcium from the sarcoplasmic reticulum during the installation of PSE (Pale, Soft, Exudative) meat, leads to increase of phospholipase A2 (PLA2) activity and consequently causes a higher lipid oxidation. In contrast, glutathione peroxidase (GSH-Px) is a selenium-dependent antioxidant enzyme that prevents the oxidative damage. The aim of this work was to investigate the secreted PLA2 (sPLA2) and GSH-PX activities in PSE poultry meat. Breast meat samples (Pectoralis major m.) (n=24) were obtained from commercial slaughterhouse. Samples were classified as PSE and Control Meat based on pH and L* values, fillets with pH1h30? 6.0 and L24h* ?53.0 as PSE and fillets with pH1h30> 6.0 and L24h* 53.0 with Control. sPLA2 was analyzed using enzymatic assay kit and GSH-Px was measured a coupled assay procedure recording the NADPH (nicotinamide adenine dinucleotide phosphate reduced) oxidation. The sPLA2 average was 0.295 Umg-1 of protein for PSE meat and 0.380 Umg-1 of protein for Control meat, did not differ significantly (p >0,05). The GSH-Px activity was approximately 24,4% higher (p?0,05) for Control meat when compared to PSE meat. The sPLA2 activity of PSE fillets did not changed, however PSE fillets present the enzymatic system of antioxidant defense compromised with lower GSH-PX activity.

A liberação excessiva de cálcio do retículo sarcoplasmático durante a instalação de carnes PSE (Pale, Soft, Exudative) leva a um aumento da atividade da fosfolipase A2 (PLA2), promovendo uma maior oxidação lipídica. Por outro lado, a glutationa peroxidase (GSH-Px) é uma enzima antioxidante selênio dependente, prevenindo danos oxidativos. O objetivo deste trabalho foi investigar as atividades da PLA2 secretada (sPLA2) e da GSH-PX em filés PSE de frango. Filés de frango (Pectoralis major m.) (n=24) foram obtidos de um frigorífico comercial. As amostras foram classificadas em PSE e Controle, com base nos valores de pH e L*, filés com pH1h30 ? 6.0 e L24h* ? 53,0 como PSE e filés com pH1h30> 6,0 e L24h* 53,0 como Controle. A atividade da sPLA2 foi determinada por kit enzimático e a atividade da GSH-Px foi determinada pela oxidação do NADPH (Nicotinamida Adenina Dinucleotídeo Fosfato Reduzido). A atividade média da sPLA2 foi de 0,295 U.mg-1 de proteína para os filés PSE e de 0,380 U.mg-1 de proteína para os filés do Controle, não apresentado diferenças significativas (p >0,05). A atividade da GSH-Px foi aproximadamente 24,4% maior (p?0,05) para os filés Controle quando comparado com filés PSE. A atividade da sPLA2 em filés PSE não foi alterada, entretanto filés PSE apresentam o sistema enzimático de defesa antioxidante comprometido com menor atividade de GSH-Px.

RESUMEN

Porcine Stress Syndrome (PSS) is a syndrome that occurs in pigs. PSS animals are sensitive to the anesthetic halothane, have higher activities of Creatine Kinase (CK) and Lactate Dehydrogenase (LDH) and are predisposed to the development of PSE (Pale, Soft, Exudative) meat, compromising the meat quality. In chickens, little is known about the relationship between sensitivity to and halothane changes in the activities of these enzymes with the occurrence of PSE meat. The aim of this study was to evaluate the CK and LDH activities in sensitive and non-sensitive halothane chickens and for stress susceptibility identification and PSE meat development. Birds were exposed to halothane at a 3.0 % concentration in pure O2 for 5 min. Afterwords, they were classified into groups: sensitive to halothane (HAL +) (stiffening of the lower limbs) and Non-sensitive (HAL-) (no hardening). After 3 h and 48 h to the test, blood was collected from the wing vein gill, serum extracted and stored at 22 C until analysis of CK and LDH. No differences were observed (p ? 0.05) in CK activity for HAL+ and HAL- groups. However, differences (p ? 0.05) were observed the LDH activity at 3 h and 48 h, and 44.2 % and 66.1 % higher for the group HAL +, respectively. The determination of lactate dehydrogenase activity indicates to be an alternative to identify animals susceptible to stress thus prone to produce

PSS do inglês Pork Stress Syndrome (Síndrome do Estresse Suíno) é uma anormalidade que ocorre em suínos. Animais PSS são sensíveis ao anestésico halotano, apresentam maior atividade das enzimas Creatina Quinase (CK) e Lactato Desidrogenase (LDH) e são predispostos ao desenvolvimento de carnes PSE (Pale, Soft, Exudative), comprometendo sua qualidade. Em frangos, pouco se conhece sobre a relação entre a sensibilidade ao halotano e alterações nas atividades destas enzimas com a ocorrência de carnes PSE. O objetivo deste trabalho foi determinar as atividades das enzimas CK e LDH em frangos sensíveis e não sensíveis ao halotano para identificação da susceptibilidade ao estresse e ao desenvolvimento de carnes PSE. As aves foram expostas ao halotano na concentração de 3,0% em oxigênio puro por 5 min. Posteriormente, foram classificadas como sensível ao halotano (HAL+), quando ocorreu o enrijecimento dos membros inferiores e não sensível (HAL-), quando houve ausência de enrijecimento. Após 3 h e 48 h da realização do teste de sensibilidade ao halotano, o sangue foi coletado da veia branquial da asa e o soro foi extraído e armazenado à 22 ºC até as determinações das atividades de CK e LDH. Não foram observadas diferenças (p?0,05) na atividade de CK entre os frangos HAL+ e HAL-. Entretanto, diferenças (p?0,05) foram verificadas nas atividades de LDH nos tempos de 3 h e 48 h, sendo 44,2%