Magnesium supplementation in swine finishing stage: performance, carcass characteristics and meat quality

O objetivo deste experimento foi avaliar o efeito da inclusão de óxido de magnésio (MgO) na fase de terminação sobre o desempenho, as características de carcaça e qualidade de carne de suínos. Foram utilizados 48 suínos, suplementados com MgO por 7 dias antes do abate, sendo os tratamentos: rações com 0; 0,2; 0,4 e 0,6% de inclusão de MgO. O delineamento experimental foi em blocos casualizados, sendo os animais blocados de acordo com o peso inicial em leves, médios e pesados. O ganho diário em peso foi influenciado pelos tratamentos, apresentando efeito quadrático com ponto de máxima inclusão de 0,3% de MgO. A suplementação com MgO diminuiu as concentrações séricas de cortisol, apresentando efeito de regressão linear decrescente. A espessura de toucinho apresentou efeito de regressão quadrática, em que o ponto de mínima deposição ocorreu com a inclusão de 0,37% de MgO. Quantidade de carne na carcaça resfriada, rendimento de carne na carcaça e índice de bonificação apresentaram efeito quadrático para suplementação dietética com MgO sendo os pontos de máxima 0,31, 0,37 e 0,28% respectivamente. A porcentagem de perda de água e a perda de água no descongelamento apresentaram efeito quadrático, com pontos de mínima perda iguais a 0,31 e 0,35%, respectivamente.There was evaluated the performance, carcass characteristics and meat quality parameters of swine on the finishing stage receiving a dietetic supplementation with magnesium oxide (MgO). The animals were 48 male swine, supplemented 7 days before the slaughter by the following treatments: feed with 0; 0.2; 0.4 e 0.6% of MgO inclusion. The pigs were blocked by the initial weight as: lights, medium and heavy. The treatments had influence on the daily weight gain showing a quadratic effect, maximum inclusion point 0.3% MgO. The effect on the plasmatic cortisol and on the carcass yield was a linear decreasing regression. Back fat thickness shows a quadratic effect, minimal deposition point 0.37% MgO. Amount of meat in chilled carcass, meat yield and gratification index showed quadratic effect for the treatments, the maximum points are 0.31, 0.37 and 0.28% of inclusion respectively. Water losses and liquid losses on defrosting presented quadratic effect; the minimal point was to 0.31 and 0.35% of inclusion, respectively

Effect of low or high stress in pre-slaughter handling on pig carcass and meat quality

The objective of this study was to evaluate the consequences of low or high stress during pre-slaughter handling of pigs on their carcass and meat quality. Forty-four animals of a commercial lineage, with an average weight of 107.23±5.23 kg, were used. At lairage the animals were randomly divided into two groups, the least and the most stressed. At slaughter, during bleeding, blood samples were collected for later cortisol and lactate tests. Forty-five minutes after slaughter the initial pH of th carcasses was measured and samples of the semitendinosus muscle were collected for R-value calculation. After 24 hours of cooling, the final pH was measured, damage scores were assessed and samples of the longissimus dorsi muscle were collected to evaluate drip loss, liquid loss from defrosting and cooking, shear force, lipid oxidation, and color. The results were evaluated by analysis of variance and the means were compared by Tukey´s test. It was found that cortisol, lactate and R-value were lower and initial pH was higher for the least stressed animals, whereas the other parameters were not significantly affected. Thus, low stress in the pre-slaughter handling of pigs is effective in reducing stress and carcass damage, but has no effect on meat quality

Quality of aged meat from Charolais vs nellore cattle<br>Qualidade da carne maturada de bovines Charolês vs nelore

The aim of this study was evaluate the physical-chemical changes in aged meat from Charolais x Nellore cattle. For that, 38 male with an average weight of 437.08 ± 15.06 kg, were used. After 24 hours of refrigeration, the half right carcass was cut in the 13ª rib to collect 35cm samples from Longissimus dorsi muscle. The samples were sliced, vacuum packed and aged for zero, seven and fourteen days, after the ageing time, the samples were frozen, to make analysis of exudate water loss, shear force, pressing water loss, pH, color (L, a*, b*, chroma and hue value), sensorial analysis, microbiology, and myofibrillar fragmentation index. The experimental design was completely randomized and the data were submitted to analysis of variance and the means compared by Tukey test in 5%. The microbiological analysis showed that all the bacterium evaluated had their growth period until the aged day seven, and decreased to the aged day 14. The pH decreased with the increasing of time. The water loss and myofibrillar fragmentation index weren’t affected by the ageing period. Shear force and color components (L*, a*, b* chroma and hue value) were affected by the ageing, being the 14 days the best result. The sensorial analysis has only show differences to tenderness. The aged cattle beef vacuum packed did not lose the fresh meat characteristics, however improved the tenderness.Com o presente trabalho objetivou-se avaliar as alterações físico-químicas na carne maturada de bovinos Charolês x Nelore. Para isso foram utilizados 38 bovinos inteiros, abatidos com peso médio de 437,08 (± 15,06 kg). Após 24 horas de resfriamento, as meias carcaças direita foram seccionadas na altura da 13ª costela para retirada de uma amostra de 35 cm do músculo longissimus dorsi (contra-filé), em sentido caudal – cranial. As amostras foram fatiadas, embaladas a vácuo e maturadas por zero, sete e quatorze dias. Após o término do período de maturação as carnes foram congeladas para posterior realização das análises de: perda de água por exsudato, força de cisalhamento, perda de água por pressão, pH, cor (valor de L*, a*, b*, croma e tonalidade), análise sensorial, microbiologia e índice de fragmentação miofibrilar. Todas as análises foram realizadas no Laboratório de Análise de Produtos de Origem Animal, da Universidade Estadual de Londrina. O delineamento experimental foi completamente casualizado e os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey a 5%. A Análise microbiológica revelou que todas as bactérias avaliadas tiveram crescimento até o dia sete de maturação, porém diminuíram no tempo 14 dias de maturação. O pH diminuiu com o aumento do período de maturação. A perda de água por pressão e o índice de fragmentação miofibrilar, não foram alterados com o tempo de maturação. A força de cisalhamento e os componentes da cor (L, a*, b*, croma e tonalidade) foram influenciados pelos tempos de maturação, sendo o tempo 14 dias o melhor deles. A análise sensorial só apresentou diferença para maciez. A carne bovina maturada embalada a vácuo não perdeu suas características de carne, entretanto melhorou a maciez

Influence of immunocastration (Bopriva®) in weight gain, carcass characteristics and meat quality of Nellore

The objective of this study was evaluate the effects of immunocastration on body weight gain, carcass characteristics and meat quality of Nellore beef cattle. Eighty Nellore beef cattle, with initial body weight of 357±8.63 kg, were placed in feedlots and distributed in two treatments (40 animals per treatments) as follow: one - non-vaccinated bulls and two - immunocastrated bulls (Bopriva®, Pfizer Animal Health). The animals placed on treatment two were vaccinated in two doses, first application 30 days before they arrive on the feedlots and second on the day they arrive on feedlots. After 67 days of experimental period, was calculated the daily gain of live weight in kg/day of the 80 animals and selected 20 animals from each treatment for the slaughter and carcass evaluations, and ten from each group for the meat analyzes. The data were submitted to analysis of variance. Immunocastrated animals showed lower daily weight gain, hot carcass weight, carcass yield, pH, leg thickness, muscle depth, loin muscle area, carcass muscle percentage, shear force and moisture. However, this animals had higher concentration of lactate and cortisol blood, chest depth, fat thickness, finishing degree, a *, b * and c*, liquid loss in thawing process, myofibrillar fragmentation index and ether extract of meat when compared to non-vaccinated bulss. The immunocastration (Bopriva®) is an alternative for improving the quality of meat by the higher fat deposition and by the reduction of the shear force of the meat when compared to non-vaccinated bulls

Performance, carcass and meat quality of ewes supplemented with magnesium oxide

The objective of this study was to evaluate the performance, the carcass and meat characteristics of ewes supplemented with magnesium oxide. Eighteen 6-year-old Santa Ines ewes were used in a completely randomized experimental design, where three levels of supplementation (0.0, 0.1 and 0.2% magnesium oxide in the concentrate) were tested, with six replicates. Final weight, weight gain, feed intake and feed conversion were not affected by levels of magnesium supplementation. Hot and cold carcass weights showed linear increasing and quadratic responses, respectively, according to supplementation with magnesium. Carcass measurements such as length, depth, and measures of arm and leg were not affected by supplementation. Depth and width of the longissimus muscle and rib-eye area were not affected; however, marbling and ether extract increased linearly with supplementation. Water loss and color were not affected. Lipid oxidation and shear force were not affected by supplementation, while the myofibrillar fragmentation index showed a quadratic regression. There was a linear decrease in pH with magnesium supplementation. Supplementation with magnesium can improve carcass and meat pH, but can act negatively by increasing the amount of marbling and ether extract of meat

Quality of aged ewe meat in vacuum-packaging system for different storage periods<br>Qualidade da carne maturada de ovelhas em sistema de embalagem a vácuo durante diferentes períodos de acondicionamento

Consumers believe tenderness to be most important organoleptic characteristic of meat. However, there is great variability in the tenderness of meat available to consumers; one method to reduce the variability and improve tenderness would be to promote meat aging. The aim of this study was to evaluate the quality of aged ewe meat. The experiment was conducted at the State University of Londrina. It was used eighteen Santa Ines ewes. After slaughter, the Longissimus dorsi muscle were collected and subjected to treatment, three different aging times: zero, four and eight days at 5 ± 2°C. The increase in aging time caused a decrease in pH. The L*, a* and c* values increase linearly with the aging period. The b* and h* values showed a quadratic regression. The mesophilic and psychrotrophic count showed a linear increase. The myofibrillar fragmentation index showed a quadratic regression, and the shear force decreased linearly. In a sensory analysis, a difference in the odor intensity of the meat was observed. The microbiological count indicated that the meat was fit for consumption. The aging promoted improvements in the quality of sheep meat.<p><p> Os consumidores acreditam que a maciez é a característica organoléptica mais importante da carne. No entanto, há grande variabilidade na maciez da carne disponível para os consumidores, um método de reduzir a variabilidade e melhorar a maciez seria promover a maturação da carne. O objetivo deste estudo foi avaliar a qualidade da carne maturada de ovelhas. O experimento foi conduzido na Universidade Estadual de Londrina. Foram utilizadas 18 ovelhas da raça Santa Inês. Após o abate, o músculo Longissimus dorsi foram coletados e submetidos ao tratamento, três diferentes tempos de maturação: zero, quatro e oito dias a 5 ± 2 ° C. O aumento do tempo de maturação provocou uma redução no pH. Os valores de L *, a * e c* aumentam de forma linear com o tempo de maturação. Os valores b * e h * apresentaram uma regressão quadrática. A contagem de mesófilos e psicrotróficos apresentaram um aumento linear. O índice de fragmentação miofibrilar apresentou uma regressão quadrática, e a força de cisalhamento diminuiu linearmente. Na análise sensorial, uma diferença na intensidade de odor da carne foi observada. A contagem microbiológica indicou que a carne estava apta para consumo. A maturação promoveu melhorias na qualidade da carne de ovelhas