ABSTRACT. The influence of harvest method on proximate composition, protein oxidation, and texture profile of beef from Nellore cattle were investigated. Longissimus lumborum (LL) muscles were obtained from twelve grain-fed Nellore carcasses. The animals were slaughtered after stunning (STU; n=6) or without stunning (WST; n=6) and after 24 hours postmortem, the LL was sliced into 2.54-cm steaks, packed under aerobic conditions, and stored at 4°C for nine days. Proximate composition was analyzed on day 0, whereas protein oxidation (carbonyl content) and texture profile (hardness, chewiness, cohesiveness, and springiness) were evaluated on days 0, 3, 6, and 9. STU and WST steaks exhibited similar proximate composition, hardness, and chewiness (p > 0.05). WST steaks exhibited greater protein oxidation and lower cohesiveness than their STU counterparts on day 0 (p < 0.05). Concerning the storage period, WST steaks demonstrated a decrease in springiness and a more pronounced increase in cohesiveness than their STU counterparts (p < 0.05). These results indicated that the harvest method influenced LL protein oxidation and texture profile from Bos indicus cattle.

RESUMO: O objetivo desse estudo foi investigar a influência do tipo muscular na oxidação proteica, perfil de textura (dureza, elasticidade, coesividade e mastigabilidade) e composição centesimal da carne de bovinos Bos indicus (Nelore) terminados com grãos no Brasil. Os músculos longissimus lumborum (LL) e psoas major (PM) foram obtidos 24 horas post mortem de oito (n=8) carcaças de touros Nelore, cortados em cinco bifes (1,5 cm), e dispostos em condições aeróbicas por nove dias a 4 °C. Composição centesimal e perfil de textura foram analisados no dia 0, enquanto que a oxidação proteica foi analisada durante 9 dias de estocagem. Os bifes LL demonstraram maior (P<0.05) concentração de proteína em relação aos bifes PM, enquanto que PM apresentou maior (P<0.05) conteúdo de lipídeos e cinzas que LL. Além disso, os bifes LL exibiram maior (P<0,05) dureza, elasticidade, coesividade e mastigabilidade em relação aos bifes PM. Em contraste, a oxidação proteica foi maior (P<0,05) nos bifes PM do que nos bifes LL em todos os dias de estocagem. Os resultados sugerem que as diferenças no metabolismo e na composição muscular contribuíram para a variação nos atributos bioquímicos e perfil de textura entre os bifes LL e PM. Estratégias músculo-específicas são indicadas a fim de promover a estabilidade de cor nos bifes PM oriundos de bovinos Bos indicus terminados com grãos.

ABSTRACT: The aim of this research was to investigate the influence of muscle type on protein oxidation, texture profile (hardness, springiness, cohesiveness and chewiness) and proximate composition of beef from grain-finished Bos indicus (Nellore) cattle in Brazil. The muscles longissimus lumborum (LL) and psoas major (PM) were collected 24 h post mortem from eight (n=8) Nellore bull carcasses, fabricated into five steaks (1.5-cm) and displayed under aerobic conditions for nine days at 4 °C. Proximate composition and texture profile were analyzed on day 0, whereas protein oxidation was analyzed during 9 days of storage. LL exhibited greater (P<0.05) protein concentration than PM steaks, whereas PM demonstrated greater (P<0.05) lipid and ash content than their correlative LL. In addition, LL steaks exhibited greater (P<0.05) hardness, springiness, cohesiveness and chewiness than PM steaks. In contrast, protein oxidation was greater (P<0.05) in PM than in LL steaks throughout the storage. The results suggest that the differences of muscle metabolism and composition contributed to the variation on biochemical attributes and texture profile of LL and PM steaks. Muscle-specific strategies are indicated to improve the color stability of PM steaks from grain-finished Bos indicus cattle.

O coelho branco da Nova Zelândia (Oryctolagus cuniculus) é freqüentemente utilizado como modelo em estudos in vivo. Contudo, as informações referentes aos cuidados no emprego deste animal como modelo experimental são limitadas. Esta revisão da literatura pretende rever a literatura desde a seleção do modelo animal até a sua morte, enfatizando, os procedimentos para transporte, criação, reprodução, comportamento, acomodação, anestesia e manejo dos animais, de forma a racionalizar a utilização desses animais reconhecendo as características próprias dessa espécie. Conclui-se que o coelho constitui um modelo adequado e viável para cirurgia experimental.

The white New Zealand rabbit (Oryctolagus cuniculus) is frequently used as a model for in vivo studies. However, information on precautions when using this animal as an experimental model is limited. This review of the literature covers the gamut from the selection of the animal model all the way to its death, and describes procedures for transporting, raising, breeding, housing, administering anesthesia and handling so as to rationalize the utilization of this species while exploiting its unique characteristics. Based upon the literature and our own experience with white New Zealand rabbits, we conclude that the rabbit is an adequate model for experimental surgery.