RESUMO
One hundred forty-four steers were group-housed in 24 pens that were randomly assigned to one of four dietary treatments defined by the proportion of wet distiller grain plus solubles (WDGS; 0, 15, 30, or 45%) and fed for 84 d pre-slaughter. Animal performance was evaluated using the pen as the experimental unit. Whereas for carcass and meat quality characteristics, meat oxidative stability, and the consumer sensory quality of longissimus thoracis muscle one animal from each pen was randomly selected and used as the experimental unit. No differences (P > 0.05) were observed for subcutaneous fat thickness, rib eye area, marbling score or pH, color parameters, proximate composition, sarcomere length, Warner Bratzler shear force, and cooking loss. Feeding WDGS linearly increased total PUFA (P = 0.05), C18:2 n-6 (P = 0.004) proportions, and n-6/n-3 ratio (P < 0.01) but reduced C16:1 to C18:0 ratio (P < 0.01). Lipid oxidation was greater in beef from steers fed 30% and 45% WDGS (P = 0.05). Dietary WDGS linearly improved (P < 0.05) flavor and overall linking score in the consumer sensory panel.
Assuntos
Ração Animal , Zea mays , Bovinos , Animais , Ração Animal/análise , Carne/análise , Dieta/veterinária , Grão Comestível/química , Composição CorporalRESUMO
Angus steers were grazed on unsupplemented pasture (CNTRL), pasture supplemented with 0.7% BW cracked corn (FLAX-0), FLAX-0 with 0.125% and 0.250% BW of whole flaxseed (FLAX-1 and FLAX-2). Six steers were grazed per treatment for 70 days, with start and finish weights of 458 and 508 kg. At 24 h post slaughter, longissimus thoracis were harvested, and steaks assigned to treatments of postmortem aging time under vacuum (PM; 3, 14 and 56 days) with or without five days of aerobic exposure (AE). Meat antioxidant status was higher (P<0.05) when feeding CNTRL and FLAX-1 than FLAX-0 and FLAX-2. Under AE, lipid oxidation was highest for FLAX-2 (P<0.05), and lowest for FLAX-1. Greatest TBARs and lowest antioxidant capacity and redness values were obtained with AE and the longer PM (P<0.05). Beef oxidative stability through AE improved by adding a low flaxseed level to supplemented corn grain, but deteriorated by adding a high flaxseed level or by extending PM.
Assuntos
Antioxidantes/metabolismo , Dieta/veterinária , Linho/química , Peroxidação de Lipídeos , Músculo Esquelético/metabolismo , Sementes/química , Zea mays/química , Animais , Animais Endogâmicos , Antioxidantes/análise , Argentina , Bovinos , Dieta/efeitos adversos , Gorduras na Dieta/análise , Linho/efeitos adversos , Embalagem de Alimentos , Qualidade dos Alimentos , Armazenamento de Alimentos , Herbivoria , Humanos , Masculino , Carne/análise , Músculo Esquelético/crescimento & desenvolvimento , Oxirredução , Pigmentos Biológicos/análise , Pigmentos Biológicos/biossíntese , Sementes/efeitos adversos , Aumento de PesoRESUMO
The aim of this study was to evaluate the effect of genetic variants on candidate genes corresponding to the sterol recognition element-binding protein-1 (SREBP-1) signaling pathway and stearoyl-CoA desaturases (SCD1 and SCD5) on muscle fatty acid (FA) composition of Brangus steers fattened on grass. FA profiles were measured on Longissimus lumborum muscle samples using a gas chromatography-flame ionization detection technique. A total of 43 tag single-nucleotide polymorphisms on the SCD1, SCD5, SREBP-1, SCAP, INSIG1, INSIG2, MBTPS1, MBTPS2, and SRPR genes were genotyped on 246 steers to perform a marker-trait association study. To evaluate the influence of the Indicine breed in the composite breed, additional groups of 48 Angus, 18 Hereford, 75 Hereford x Angus, and 36 Limousin x Hereford-Angus steers were also genotyped. To perform the association analysis, FA data were grouped according to the number of carbon atoms and/or number of double bonds (i.e. SFA, MUFA, PUFA, etc.). In addition, different indexes that reflect the activity of FA desaturase and elongase enzymes were calculated. SCD1 markers significantly affected C14:1/(C14:0 + C14:1) and C18:1/(C18:0 + C18:1) indexes, whereas one SNP in SCD5 was correlated with the C16:1/(C16:0 + C16:1) index. Polymorphisms in the signal recognition particle receptor (SRPR) gene were associated with all the estimated desaturase indexes. Because the evaluated markers showed no effect on total lipid content of beef, this work supports the potential utilization of these markers for the improvement of grass-fed beef without undesirable side effects.
Assuntos
Bovinos/genética , Variação Genética , Carne/análise , Valor Nutritivo/genética , Transdução de Sinais/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Animais , Argentina , Cromatografia Gasosa/veterinária , Ácidos Graxos/análise , Marcadores Genéticos , Genótipo , Modelos Lineares , Músculo Esquelético/química , Poaceae , Receptores Citoplasmáticos e Nucleares/genética , Receptores de Peptídeos/genética , Estearoil-CoA Dessaturase/genéticaRESUMO
The somatotropic axis is a major regulatory pathway of energy metabolism during postnatal growth in mammals. Genes involved in this pathway influence many economically important traits. The association of selected SNPs in these genes with carcass traits was examined in grazing Brangus steers. These traits included final live weight, ultrasound backfat thickness (UBFT), rib-eye area, kidney fat weight, hot carcass weight, and intramuscular fat percentage (%IMF). Genomic DNA (N = 246) was genotyped for a panel of 15 tag SNPs located in the growth hormone receptor (GHR), insulin-like growth factor I, insulin-like growth factor-binding protein 6, pro-melanin-concentrating hormone, suppressor of cytokine signaling 2, and signal transducer and activator of transcription 6 (STAT6) genes. Allelic and haplotype frequencies were compared with those of a sample of European breeds (N = 177 steers). Two tag SNPs in the GHR affected %IMF; one of them (ss86273136) was also strongly associated with UBFT (P < 0.003). The frequency of the most favorable GHR haplotype for %IMF was lower in Brangus steers. Moreover, the haplotype carrying two unfavorable alleles was present at a frequency of 31% in this group. Four tag SNPs on STAT6 had a significant effect on UBFT. One of these, SNP ss115492467, was also associated with %IMF. The STAT6 haplotype, including all the alleles favoring UBFT, was the most abundant variant (34%) in the European cattle, while it had a frequency of 14% in the Brangus steers. The four less favorable variants (absent in the European cattle) were found at a frequency of 38% in the Brangus steers. These results support the association of GHR and STAT6 SNP with carcass traits in composite breeds, such as Brangus, under grazing conditions.
Assuntos
Composição Corporal/genética , Bovinos/anatomia & histologia , Estudos de Associação Genética , Marcadores Genéticos , Aumento de Peso/genética , Tecido Adiposo/química , Alelos , Animais , Argentina , Pesos e Medidas Corporais , Cruzamento , Bovinos/genética , Genótipo , Haplótipos , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/genética , Fator de Crescimento Insulin-Like I/genética , Carne , Músculo Esquelético/química , Fenótipo , Polimorfismo de Nucleotídeo Único , Receptores da Somatotropina/genética , Fator de Transcrição STAT6/genéticaRESUMO
Twenty-eight Angus (289 +/- 3.8 kg) steers were used in a completely randomized design to evaluate the effect of isocaloric supplementation of 2 different energy sources to steers rotationally grazing tall fescue pastures for 197 d in comparison to positive and negative controls. Steers were supplemented with either corn grain (0.52% BW on a DM basis; PC) or soybean hulls plus corn oil (0.45% BW on a DM basis + 0.10% BW on an as-fed basis; PO) using Calan gates for individual intake measurement. Negative, pasture only (PA), and positive, high-concentrate control diets (85% concentrate:15% roughage on DM basis; C) were also included in the study. Steers on PC, PO, and PA treatments were managed together under a rotational grazing system, whereas C steers were fed a high-concentrate diet for the final 113 d using Calan gates. Forage DMI and apparent DM and NDF digestibility for the grazing treatments were evaluated using Cr(2)O(5) and indigestible NDF as digesta markers. Energy supplementation decreased (P = 0.02) forage DMI (% of BW) with respect to PA, but not (P = 0.58) total DMI. There were no differences (P = 0.53) among grazing treatments on apparent total DM digestibility. However, NDF digestibility was less (P < or = 0.05) in PC than in PO and PA; the latter 2 treatments did not differ (P > 0.05). Overall ADG was greater (P < 0.01) in supplemented, regardless of type, than in nonsupplemented grazing treatments. During the final 113 d, ADG was greater (P < 0.01) in C than in the grazing treatments. Overall supplement conversion did not differ (P = 0.73) between supplement types and was less (P = 0.006) than C. Carcass traits did not differ (P > 0.05) between energy sources. Dressing percentage and HCW were greater (P < 0.01) in supplemented cattle than in PA. Fat thickness and KPH percentage for PA were less (P < 0.05) than for PO but did not differ (P > 0.14) from PC. Marbling score, LM area, and quality grade did not differ (P > 0.05) between grazing treatments. Hot carcass weight for C was heavier (P < 0.001) than for pastured cattle. Quality and yield grades of C carcasses were also greater (P < 0.001) than carcasses from pastured steers. Energy supplementation, regardless of source, to grazing steers increased ADG, dressing percentage, and carcass weight compared with PA steers; however, supplemented steers had less ADG, efficiency, dressing percentage, and carcass weight compared with high-concentrate finished steers.
Assuntos
Composição Corporal/fisiologia , Bovinos/fisiologia , Óleo de Milho/metabolismo , Suplementos Nutricionais , Digestão/fisiologia , Festuca/metabolismo , Zea mays/metabolismo , Ração Animal/análise , Ração Animal/economia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Bovinos/crescimento & desenvolvimento , Bovinos/metabolismo , Óleo de Milho/administração & dosagem , Masculino , Distribuição Aleatória , Glycine max/metabolismo , Aumento de Peso/fisiologiaRESUMO
SETTING: Four hundred and sixty-eight isoniazid (INH) resistant Mycobacterium tuberculosis isolates recovered from a selected Brazilian population. OBJECTIVE: To check for susceptibility to other chemotherapeutic drugs used in TB treatment, and to ascertain mutations involved in INH and rifampicin (RMP) resistance. DESIGN: Antimicrobial susceptibility to RMP, streptomycin and ethambutol (EMB) was evaluated by the resistance ratio method and pyrazinamide (PZA) by activity assay. Single strand conformation polymorphism (SSCP) and sequence analysis were performed in samples from this panel to confirm mutations in codon 315 of the katG and in a 69-bp region of the rpoB gene. RESULTS: Combined resistance to INH+RMP, INH+ PZA, INH+EMB, and INH+RMP+PZA was shown in respectively 272 (58.1%), 126 (26.9%), 47 (10%), 116 (24.8%) isolates. No katG mutation was found in 19 (39.6%) of 48 strains tested. Ser315Thr substitution was found in 29 (60.4%). All RMP-resistant strains tested (n = 25) showed rpoB mutations. S531L substitution was found in 15 (60%). CONCLUSION: INH-resistant strains isolated from selected Brazilian populations frequently show resistance to other first-line anti-tuberculosis drugs. rpoB mutation was responsible for RMP resistance in all strains. Among INHr strains, katG mutations were shown in only 60.4%. Genetic approaches targeting the rpoB gene but not the katG gene have a high sensitivity to detect resistance among Brazilian M. tuberculosis strains.
Assuntos
Antituberculosos/farmacologia , Isoniazida/farmacologia , Mycobacterium tuberculosis/genética , Rifampina/farmacologia , Proteínas de Bactérias/genética , Brasil , Catalase/genética , Análise Mutacional de DNA , RNA Polimerases Dirigidas por DNA/genética , Resistência Microbiana a Medicamentos , Humanos , Mycobacterium tuberculosis/patogenicidade , Polimorfismo Conformacional de Fita Simples , Prevalência , Análise de Sequência de DNA , Tuberculose Resistente a Múltiplos MedicamentosRESUMO
Foram estudadas 293 pacientes submetidas a histerectomia ou miometrectomia como cirurgia principal e selecionadas 49 que apresentaram adenomiose no exame anatomo-patologico (20, 1%). Hemorragia genital foi referida por 68, 5% das pacientes no menacme ou pre-menopausa sendo 34,2% tambem apresentavam queixa de dor no baixo ventre. Utero aumentado de volume foi verificado em 46,9% das pacientes atribuido em 56,5% a presenca de leiomioma uterino.O diagnostico clinico foi realizado em apenas 5,7% dos casos observados no menacme e/ou menopausa. Hiperplasia glandular cistica foi observada em 16,3% dos casos mas na adenomiose pura curetagem e terapeutica hormonal sao ineficazes para curar a hemorragia uterina; esse fato servira para diferenca-la da hemorragia uterina disfuncional. Proporcao consideravel de casos particularmente na pos-menopausa e achado de exame