A study was conducted to characterize lipid profiles in the M. longissimus thoracis of commercial Brazilian beef and to assess how those profiles are influenced by finishing system, genetic group, and their interaction. Intramuscular fat (IMF) and fatty acid (FA) profiles were determined in 160 bulls of the Bos taurus (n = 75) and Bos indicus (n = 85) genetic groups, finished on pasture (n = 46) or with grain supplementation (n = 114) and slaughtered in a commercial abattoir. Finishing system had a major impact on the deposition of IMF, as well as on the concentration of SFA, PUFA, and their ratio, but genetic groups showed important differences in the ability to convert SFA into cis-9 MUFA and to convert 16:0 into 18:0. When compared with pasture-finished animals, those finished with grain had greater content of IMF and SFA (P < 0.01), similar amounts of MUFA (P > 0.05), and about one-half the amount of PUFA (P < 0.01). Except for MUFA, differences in FA profiles among finishing systems were mostly mediated through their effect on IMF, even though the relationship of IMF with groups of FA differed among finishing systems. Under grain finishing, B. taurus had less SFA and greater MUFA than B. indicus (P < 0.01), but no differences were observed in PUFA (P > 0.05). With pasture-finishing, no differences were observed among the 2 genetic groups in SFA and MUFA (P > 0.05), but PUFA were decreased in B. taurus (P < 0.01). When genetic groups were compared in grain-finishing, B. taurus had a decreased ability for elongation and B. indicus had a decreased aptitude for desaturation of FA. On the other hand, with pasture-finishing a greater deposition of intermediate FA from ruminal biohydrogenation was observed in B. indicus than in B. taurus. Overall, FA profiles were affected more by finishing system in B. indicus than in B. taurus.

-The objective of this study was to characterize meat quality in Bos taurus and Bos indicus and to determine the influence of finishing system and genetic group on the physicochemical properties of the longissimus thoracis at 24 hours and 10 days post mortem (1ºC). The sample included 160 bulls of the B. taurus (n=75) and B. indicus (n=85) groups, finished either on pasture (n=46) or with grain supplementation (n=114), slaughtered at a carcass weight of 270 to 300 kg. Pasturefinished animals had higher pH, lower red content and a fat content 2.5 times lower than those finished with supplementation.Meat from supplement-finished animals had lower shear force in comparison to that from animals finished on pasture, with means of 7.7 and 8.5 kg at 24 hours, and of 5.5 and 5.9 kg at 10 days, respectively. Samples of B. taurus and B. indicus were similar in moisture and protein, but B. taurus presented higher means for ash and lower means for fat. Aged samples of B. indicus finished on pasture showed lower values for lightness and yellowness. Overall, lightness and yellow content increased and red content decreased with 10-day ageing. Means for shear force were lower in B. taurus than in B. indicus, with differences of

Physicochemical properties and fatty acid profiles of meat from Bos indicus, Bos taurus and crossbred B. taurus×B. indicus bullocks (n=216), finished on pasture or grain, were used to estimate the effects of heterosis. Meat quality and fatty acid profiles generally benefited with crossbreeding, but the advantages from heterosis differed among finishing systems. The Warner-Bratzler shear-force in fresh and aged meat was reduced due to heterosis in pasture-finishing, but the effect was minor under grain-finishing. With pasture-finishing, heterosis caused an increase of 5% in CLA concentration, but few other changes in fatty acid profiles. In grain-finishing, heterosis caused a reduction in intramuscular fat and cholesterol, increased amounts of PUFA, n-6 fatty acids and PUFA/SFA ratio, and a decline in atherogenic index. The Δ(9) desaturase estimated activity in crossbreds showed a behavior close to B. indicus, suggesting the existence of few loci and a dominance genetic effect on enzymes involved in fatty acid synthesis and metabolism.

An experiment was carried out to evaluate carcass traits of male and female broilers of two genetic strains (Paraíso Pedrês and Pescoço Pelado), slaughtered at 65, 75, 85 and 95 days of age, and reared under a semi-extensive production system. The following parameters were evaluated: body weight at slaughter (BWs), carcass weight (CW), carcass yield (CY), parts yield, including breast, drumstick, thighs, back, neck, feet, wings, abdominal fat pad (AF), and giblets (gizzard, heart, liver). Paraíso Pedrês males presented higher BWs and CW. Paraíso Pedrês females had higher breast yield. Thighs and drumstick yields were higher in Pescoço Pelado males. Back yield was similar at 85 and 95 days of age, wing yield declined with age. AF yield was higher in Paraíso Pedrês and in females. GY was affected by sex and slaughter age. The results of this work lead to the conclusion that Paraíso Pedrês males reach higher live and carcass weights at 85 and 95 days of age, and that breast yield is higher in this strain. On the other hand, Pescoço Pelado males present higher drumstick and thighs yields. Therefore, the choice of genetic strain, sex and slaughter weight will determine carcasses with different parts yield

RESUMO -Os objetivos neste trabalho foram avaliar as características de qualidade da carne, a composição centesimal e os componentes lipídicos (colesterol e ácidos graxos) do músculo longissimus thoracis de bovinos Angus (n=30) e Nelore (n=30) aos 36 meses de idade e com peso médio de carcaça de 250 kg terminados em pastagem. Os resultados de pH, luminosidade, teor de vermelho e perda de peso na cocção foram similares entre grupos genéticos. Entretanto, a carne dos animais Angus apresentou maior teor de amarelo (4,87 e 4,04) e menor força de cisalhamento (7,86 e 9,13 kg) em comparação à dos animais Nelore. A composição centesimal foi semelhante entre raças. O colesterol na carne dos bovinos Angus foi mais elevado que na dos Nelore (45,45 e 36,99 mg/100 g). Os ácidos graxos C14:0, C14:1 cis 9, C18:1 trans, C18:2n-6, C18:2 cis 9, trans 11 (CLA), C18:3n-3, total de n-3 e o total de ácidos graxos poliinsaturados foram mais elevados nos animais Nelore que nos Angus. Os totais de ácidos graxos saturados e monoinsaturados, no entanto, foram semelhantes entre grupos. A razão n-6/n-3 foi menor nos animais Nelore (1,58) que nos Angus (1,88). Os grupos genéticos de bovinos terminados a pasto influenciam a força de cisalhamento, o colesterol e o perfil de ácidos graxos. Esse efeito é mais pronunciado nos ácidos graxos poliinsaturados C18:1 trans, C18:2 cis 9, trans 11 e C18:3n-3, o que sugere uma possível diferença entre animais das raças Angus e Nelore no metabolismo da biohidrogenação. Embora menos macia, a carne de animais Nelore é nutricionalmente mais saudável que a de animais Angus, pois tem menores percentuais de colesterol e maiores quantidades de ácidos graxos n-3, precursor do CLA (C18:1 trans) e CLA.Palavras-chave: biohidrogenação, Bos indicus, Bos taurus, maciez, CLA, perfil lipídico Physicochemical parameters and fatty acid profiles in Angus and Nellore cattle finished on pastureABSTRACT -This work was carried out to evaluate the characteristics of meat quality, centesimal composition and lipid compounds (cholesterol and fatty acids) of longissimus thoracis muscle in Angus (n=30) and Nelore (n=30) bulls, at 36 months of age and 250 kg of carcass weight, finished in pasture. The results for pH, lightness, redness, cooking loss were similar among genetic groups. However, samples of Angus showed higher yellowness (4.87 and 4.04) and lower WarnerBratzler shear force (7.86 and 9.13 kg) than samples of Nelore. Centesimal composition was similar among groups.Cholesterol was higher in Angus than in Nelore (45.45 and 39.99 mg/100g). The fatty acids C14:0, C14:1 cis 9, C18:1 trans, C18:2n-6, C18:3n-3, C18:2 cis 9, trans 11 (CLA), total of n-3 and total of polyunsaturated fatty acids were higher in Nelore than in Angus. However, the total for saturated and monounsaturated fatty acids were similar among groups. The ratio n-6/n-3 was lower in Nelore (1.58) than in Angus (1.88). Genetic groups of bovines finished on pastures affect WarnerBratzler shear force, cholesterol and fatty acids profile. In fatty acids, this effect i...

RESUMONa análise do perfil de ácidos graxos monoinsaturados (AGM), os Bos taurus apresentaram os percentuais mais elevados de C14:1 cis9, C16:1 cis9, C18:1 cis9, ΣAGM e os menores de C18:1 trans. Os animais Bos taurus apresentaram maiores percentuais de C18:3 n-3, C20:4 n-6 e C22:5 n-3 (ácidos graxos poliinsaturados). Os ácidos graxos C18:2 n-6, CLA, C20:5 n-3, C22:6 n-3, ΣAGP e Σn-6 foram semelhantes entre grupos de bovinos. A razão n-6/n-3 foi menor em Bos taurus (4,63) em comparação aos Bos indicus (5,70). Em geral, o grupo genético influencia o perfil de colesterol e ácidos graxos de bovinos e esse efeito é mais pronunciado nos ácidos graxos saturados e monoinsaturados. Palavras-chave: ácidos graxos, colesterol, suplementação Lipid composition of meat from zebu and taurine cattle finished in confinementABSTRACT -This study was carried out to evaluate total lipids (TL), cholesterol and fatty acids (FA) in the longissimus dorsi muscle of Bos taurus (n=40) and Bos indicus (n=40) bulls, aged 30-36 months and 240-270 kg carcass weight, finished in the feedlot for 90 days. The total lipids content was similar in both groups. Cholesterol was higher in Bos indicus (66.95 mg/100 g) than in Bos taurus (37.37 mg/100 g). For saturated fatty acids, the means for C14:0 and C18:0 were higher in Bos indicus (3.52 and 22.45%), than in Bos taurus (3.08 e 18.67%). The C16:0 was higher inBos taurus (26.14%), as compared to Bos indicus (24.77%). For monounsaturated fatty acids (MUFA), Bos taurus had higher levels of C14:1 cis9, C16:1 cis9, C18:1 cis9, ΣMUFA but lower levels of C:18:1 trans. For polyunsaturated fatty acids (PUFA), Bos taurus presented higher percentages of C18:3 n-3, C20:4 n-6 and C22:5 n-3. The C18:2 n-6, CLA, C20:5 n-3, C22:6 n-3, ΣPUFA and Σn-6 FA were similar between the groups. The ratio n-6/n-3 was lower in Bos taurus (4.63) than in Bos indicus (5.70). In general, there was a genetic influences in the cholesterol and fatty acids of cattle profile, and this effect was more pronounced for saturated and monounsaturated fatty acids.

Meat obtained under commercial conditions shows considerable variability, mostly due to genetic background and production system. In this study, meat physicochemical properties and fatty acid profiles were analysed to investigate the feasibility of using them as tools to discriminate between meats produced by different genetic groups and finishing systems. Samples of the Longissimus thoracis were collected from 160 commercial bulls of the B. taurus (n = 75) and B. indicus (n = 85) groups, finished either on pasture (n = 46) or with grain supplementation (n = 114) and analysed by standard procedures. Data were analysed by discriminant analysis using a stepwise procedure, to select the meat characteristics that better contribute to discriminate the various groups. Our results indicate that fatty acid profiles of meat had better discriminating ability than physicochemical properties, especially to identify meat from animals finished on grain or pasture. The overall discrimination of meat from different genetic groups was achieved with a slightly lower reliability. Nonetheless, our results show that reliability of allocation to genetic group can be improved if prior information on finishing system is considered. These results are of high importance because they can be incorporated as tools to assess the authenticity of beef, particularly in meat certification programs.