Rafael Torres de Souza Rodrigues

Differences in beef quality between Angus (Bos taurus taurus) and Nellore (Bos taurus indicus) Cattle through a proteomic and phosphoproteomic approach

Proteins are the major constituents of muscle and are key molecules regulating the metabolic changes during conversion of muscle to meat. Brazil is one of the largest exporters of beef and most Brazilian cattle are composed by zebu (Nellore) genotype. Bos indicus beef is generally leaner and tougher than Bos taurus such as Angus. The aim of this study was to compare the muscle proteomic and phosphoproteomic profile of Angus and Nellore. Seven animals of each breed previously subjected the same growth management were confined for 84 days. Proteins were extracted from Longissimus lumborum samples collected immediately after slaughter and separated by two-dimensional electrophoresis. Pro-Q Diamond stain was used in phosphoproteomics. Proteins identification was performed using matrix assisted laser desorption/ionization time-of-flight mass spectrometry. Tropomyosin alpha-1 chain, troponin-T, myosin light chain-1 fragment, cytoplasmic malate dehydrogenase, alpha-enolase and 78 kDa glucose-regulated protein were more abundant in Nellore, while myosin light chain 3, prohibitin, mitochondrial stress-70 protein and heat shock 70 kDa protein 6 were more abundant in Angus (P<0.05). Nellore had higher phosphorylation of myosin regulatory light chain-2, alpha actin-1, triosephosphate isomerase and 14-3-3 protein epsilon. However, Angus had greater phosphorylation of phosphoglucomutase-1 and troponin-T (P<0.05). Therefore, proteins involved in contraction and muscle organization, myofilaments expressed in fast or slow-twitch fibers and heat shock proteins localized in mitochondria or sarcoplasmic reticulum and involved in cell flux of calcium and apoptosis might be associated with differences in beef quality between Angus and Nellore. Furthermore, prohibitin appears to be a potential biomarker of intramuscular fat in cattle. Additionally, differences in phosphorylation of myofilaments and glycolytic enzymes could be involved with differences in muscle contraction force, susceptibility to calpain, apoptosis and postmortem glycolysis, which might also be related to differences in beef quality among Angus and Nellore.

Digestibilidade de Cordeiros em Diferentes Níveis de Oferta de Alimentos

Objetivou-se avaliar o consumo e a digestibilidade de cordeiros sem raca definida (SRD) (45 animais), em diferentes classes sexuais (15 machos inteiros, 15 machos castrados e 15 femeas), mantidos em diferentes niveis de alimentacao (a vontade, 25 e 50% de restricao). A dieta foi constituida de capimelefante e concentrado com relacao volumoso:concentrado de 40:60. Nao houve diferencas (P>0,05) entre as classes sexuais e nao ocorreu interacao (P>0,05) da classe sexual com os niveis de alimentacao para as variaveis analisadas. Por outro lado, houve efeito da restricao alimentar sobre esses parâmetros (P<0,05). A restricao alimentar reduziu os valores de consumo e elevou os coeficientes de digestibilidade da materia seca e dos nutrientes. DOI: 10.15528/2176-4158/rcpa.v14n1p73-76

Cinética de degradação de frações nutricionais de euforbiáceas

In order to determine the composition and the in situ degradability of the dry matter, crude protein and neutral detergent fiber of hays of castor cv. Paraguacu (Ricinus communis), castor cv. Nordestina (Ricinus communis), jatropha (Jatropha curcas) and manicoba (Manihot pseudoglaziovii). Three rumen canulated undefined breed sheep were used. In each animal were incubated 12 bags for 6; 12; 24; 48 and 96 hour, being three bags by hay of euphorbiaceae. The content of protein ranged between 10.3% for the hay of jatropha and 19.6% for the hay of manicoba. The neutral detergent fiber value was similar between the hay of jatropha and the hay of manicoba, while the hays of castors presented lower concentrations between themselves. The castor Paraguacu hay presented superior and faster dry matter degradation, with value of 85.5% stagnated at 44 hour. The hay of manicoba and the hay of jatropha showed similar degradability of crude protein with final valor of 92.5% degraded at 40 and 46 hour, respectively. The jatropha hay presented neutral detergent fiber degradation of 68.0% and was superior to other euphorbiaceous hay, but, showed slower degradation rate, stagnated at 86 hour. The hays of castors were superior to the other hays of euphorbiaceous for chemical composition, the coefficients of ruminal degradation and the potential and effective degradation of nutrients.

Biometria da cabeça e da cavidade craniana de ovinos deslanados sem raça definida (Ovis aries LINNAEUS, 1758) em Petrolina/Pernambuco, Brasil

A especie ovina e largamente utilizada na regiao Nordeste do Brasil por apresentar alta rusticidade. No entanto, sua anatomia ainda e pouco estudada. Assim, crescem os estudos para gerar subsidios tecnico-cientificos aqueles profissionais que trabalham com as areas aplicadas da Medicina Veterinaria e afins. O objetivo do presente estudo foi estabelecer correlacoes entre as dimensoes da cabeca e da cavidade craniana, utilizando 80 ovinos, 40 machos e 40 femeas, com media de peso entre 27,0 e 33,0 kg. Em femeas, foi observada correlacao entre a massa corporea e o comprimento da cabeca; entre a massa corporea e largura da cabeca; entre o comprimento da cabeca e sua respectiva largura; entre comprimento da cabeca e o comprimento da cavidade craniana e entre a altura da cabeca e o comprimento da cavidade craniana. As demais dimensoes, nas femeas, nao tiveram correlacao estatisticamente significativa. Ja em animais do sexo masculino, foi possivel evidenciar correlacao apenas entre a altura da cabeca e altura da cavidade craniana. Desta forma, e possivel concluir que, quanto maiores forem as proporcoes da cabeca, maiores serao as dimensoes e volume intracranianos.