BackgroundFatty acid type in beef can be detrimental to human health and has received considerable attention in recent years. The aim of this study was to identify differentially expressed genes in longissimus thoracis muscle of 48 Nellore young bulls with extreme phenotypes for fatty acid composition of intramuscular fat by RNA-seq technique.ResultsDifferential expression analyses between animals with extreme phenotype for fatty acid composition showed a total of 13 differentially expressed genes for myristic (C14:0), 35 for palmitic (C16:0), 187 for stearic (C18:0), 371 for oleic (C18:1, cis-9), 24 for conjugated linoleic (C18:2 cis-9, trans11, CLA), 89 for linoleic (C18:2 cis-9,12 n6), and 110 genes for α-linolenic (C18:3 n3) fatty acids. For the respective sums of the individual fatty acids, 51 differentially expressed genes for saturated fatty acids (SFA), 336 for monounsaturated (MUFA), 131 for polyunsaturated (PUFA), 92 for PUFA/SFA ratio, 55 for ω3, 627 for ω6, and 22 for ω6/ω3 ratio were identified. Functional annotation analyses identified several genes associated with fatty acid metabolism, such as those involved in intra and extra-cellular transport of fatty acid synthesis precursors in intramuscular fat of longissimus thoracis muscle. Some of them must be highlighted, such as: ACSM3 and ACSS1 genes, which work as a precursor in fatty acid synthesis; DGAT2 gene that acts in the deposition of saturated fat in the adipose tissue; GPP and LPL genes that support the synthesis of insulin, stimulating both the glucose synthesis and the amino acids entry into the cells; and the BDH1 gene, which is responsible for the synthesis and degradation of ketone bodies used in the synthesis of ATP.ConclusionSeveral genes related to lipid metabolism and fatty acid composition were identified. These findings must contribute to the elucidation of the genetic basis to improve Nellore meat quality traits, with emphasis on human health. Additionally, it can also contribute to improve the knowledge of fatty acid biosynthesis and the selection of animals with better nutritional quality.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-3232-y) contains supplementary material, which is available to authorized users.

This study aimed to characterise progeny of sires representing major families in the Poll Nellore breed. Fourteen Poll Nellore sires, two Angus sires and one Brahman sire were mated by AI to~400 multiparous Poll Nellore dams. Calves were raised and stocked on pasture in central Brazil until reaching~18 months of age, then fed a sugarcane bagasse-based diet on an ad libitum basis until reaching market weight and finish (average 23 months). There were 236 Poll Nellore (N), 38 Angus · Poll Nellore (AN) and 31 Brahman · Poll Nellore (BN) calves born in total. The weaning and 423-day weight weights, and growth rates and pre-and post-weaning were greater (P < 0.05) in males than in female calves, and were influenced by breed and by sire within the N animals. The weaning weights were higher (P < 0.05) in AN and BN than in N calves. The 423-day weight weights were greater (P < 0.05) in AN calves, followed by BN, with straightbred N being lightest. Feedlot average daily gain was unaffected (P > 0.05) by sex or by sire within N, but was lowest (P < 0.05) in N cattle, and highest in AN and BN animals, which did not differ (P > 0.05). Heifers reached the end of the study with lower bodyweight (BW) and dressing percentage than steers, resulting in lower carcass weights, smaller longissimus muscle areas (LMA), but greater 12th to 13th rib backfat (BF) and similar marbling score and mean shear force. However, the proportion of carcasses grading Choice or Prime was numerically greater in heifers than in steers (23.6% vs 9.8%). AN cattle reached greater harvest weights than BN, and those were heavier than N cattle (P < 0.001). However, dressing percentages were lowest in AN animals, so that there was no significant difference in carcass weight between AN and BN cattle. AN carcasses also had greater LMA, BF and marbling scores than the N carcasses. The proportion of carcasses grading Choice or Prime was numerically greater in AN cattle than in the BN and N groups (25.9%, 11.8% and 15.9%, respectively). Steaks from AN calves were more tender than N steaks, with the BN steaks being intermediate. There was significant variation among N sires for final BW, dressing percentage, carcass weight, LMA and marbling score, but not for BF or mean shear force. The percentages of carcasses of N cattle grading Choice or Prime ranged from 0% to 61.5%. Three N sires produced progeny with greater than 40% of carcasses grading Choice or above (Berílio OB, Furador OB, and Litoral OB). Likewise, three N sires (Blitz OB, Furador OB and Sossego OB) had progeny with 67%, 62% and 75%, respectively, of steaks classified as tender. This study confirmed that Zebu cattle have inferior carcass and meat quality relative to AN crossbreds under tropical conditions, however there is substantial variation within the N breed for these traits, and several sires have a proportion of their progeny comparable in terms of meat tenderness to those of Angus sires.

This study investigated how different finishing periods and the inclusion of whole cottonseed and vitamin E in diets fed to feedlot cattle affect meat lipid composition and sensory traits of fresh beef and hamburgers. Fifty-four Nellore bulls were fed 3 different diets (C: control; WCS: 30% whole cottonseed; WCSE: 30% whole cottonseed plus vitamin E) during finishing periods of 83, 104, and 111days. The inclusion of cottonseed did not affect saturated fatty acid levels (SFA), but increased the levels of certain polyunsaturated fatty acids (PUFA) in meat. The SFA levels and n-6/n-3 ratio increased over the length of finishing period. In general, meat products from animals fed the WCS and WCSE diets were more tender and juicier (P<0.05); however, an off-flavor was detected by the panelists (P<0.05). The sensory difference test results showed that the WCS hamburger flavor was not significantly different for the studied lengths of finishing period. Addition of 30% DM cottonseed in diets for cattle did not promote changes likely to affect human health, and it provided a more tender and juiciness meat, however differences in the off flavor were perceived only by panelist.

O desmame dos leitões é um período de grande desafio que gera queda de desempenho dos animais, por influência de inúmeros fatores estressantes. A queda da imunidade pode causar desequilíbrio intestinal, tornando os animais mais susceptíveis a agentes patogênicos entéricos, com consequente queda no desempenho. O uso de antibióticos na alimentação animal, principalmente em suínos e aves, tem despertado ampla discussão nos vários segmentos da produção animal, dadas às restrições impostas pela Comunidade Europeia. Por outro lado, a utilização de probióticos como aditivos promotores de crescimento nas criações intensivas apresentam uma tendência mundial de crescimento, embora os estudos científicos apresentem resultados contraditórios. Este artigo tem por objetivo sistematizar informações sobre a utilização de probióticos em leitões.

Primeiramente aos meus pais, Nilcéa e Nivaldo, que permitiram que todos meus sonhos fossem possíveis, me apoiando sempre que necessário, e permitindo que nunca me sentisse sozinho. À Esther, meu amor, por ter feito parte de todas as alegrias e percalços durante o mestrado, também sempre me apoiando e incentivando, ficando sempre ao meu lado e sempre com a nossa fiel escudeira Stella. À Universidade de São Paulo, especialmente ao Departamento de Nutrição e Produção animal, que permitiu que eu realizasse meu trabalho em suas depêndencias, proporcionando crescimentos pessoal e profissional. À minha orientadora, Prof a. Dr a. Angélica Simone Cravo Pereira, pelos constantes ensinamentos e sugestões, ajudando sempre no meu crescimento. Ao Prof. Dr. Fernando Baldi pela co-orientação e constante apoio durante todas as fases do meu trabalho, me ajudando sempre. Aos professores do VNP pelos constantes ensinamentos, conversas e dedicação. À Ale e Fábia pelo apoio e ajuda sempre que necessário. Ao João Paulo pela ajuda e dedicação. À toda equipe do Laboratório de Ciência da Carne pelas conversas, ajudas, aprendizados e momentos de descontração. Aos alunos das turmas 77 e 78 pela paciência e dedicação por me escutarem e me mostrarem o quão gostoso é dar aula. À todos os colegas da pós por todos os momentos juntos. Na alegria ou na tristeza, na saúde ou na doença! A família que escolhemos. À república Hard Roça, Maria, Vivi, Nara e ao agregados pelas risadas, conversas, creches caninas e apoio. Às meninas da limpeza por sempre manterem nosso ambiente de trabalho limpo e por sempre proporcionarem um ótimo café com muitas conversas! À todos os funcionários do campus que foram sempre muito solícitos e sempre ajudaram em todas as ocasiões. À Simi, Renata e Lu por todo o apoio durante as análises e por todas as conversas. À Mari, Rômulo, Felipão e Márcio pelas conversas e cervejas. À Larissa Fonseca e à Dra. Daniele Gimenez pelo intensivão em Jaboticabal, por terem sempre me ajudado e apoiado. Vocês foram essenciais para que eu realizasse meu projeto.