Hormonal Receptors in Skeletal Muscles of Dystrophic Mdx Mice

Introduction. Several evidences show that muscles have an endocrine function. Glucocorticoid, estrogen, progesterone, and testosterone receptors have already been found in normal skeletal muscles, but not in dystrophic muscles. Methods. the gene expression of hormone receptors was compared between dystrophic and healthy muscles in mdx and C57BL6 mice strains. Results. the mdx mice showed a significant increase in the steroid receptors mRNA when compared to the C57BL6 mice: levels of androgen(s) receptors in the heart, estrogen receptors alpha in the EDL, and estrogen receptors beta in the quadriceps were increased. in addition, significant lowered levels of some other hormone receptors were found: corticosteroid receptors in the EDL and estrogen receptors alpha in the quadriceps. Conclusion. Dystrophic muscles bear significant differences in the expression of hormone receptors when compared to the C57BL6 mice strain. the importance of such differences is yet to be better understood

Medidas objetivas das carcaças e composição química do lombo de cordeiros alimentados e terminados com três níveis de proteína bruta em creep feeding Measurements of carcass and chemical composition of loin of suffolk lambs fed three crude protein levels in creep feeding

Objetivou-se avaliar o efeito de três níveis de proteína (15, 20 e 25% PB) na ração sobre as medidas objetivas das carcaças e do músculo Longissimus dorsi, os pesos e rendimentos dos cortes, além da composição química e maciez da carne de cordeiros Suffolk alimentados e terminados em creep feeding. Foram utilizados 15 cordeiros inteiros, originados de partos simples, abatidos ao atingirem peso vivo final de 28 kg. As carcaças foram mantidas em câmara de refrigeração a 5ºC, durante 24 horas, para registro das medidas objetivas, realizado após separação dos cortes comerciais, na meia-carcaça esquerda. A área do músculo Longissimus dorsi foi mensurada para determinação da área de olho de lombo (AOL cm²). No lombo esquerdo congelado, realizou-se a análise de composição química e, no direito, também congelado, o teste de maciez peloWarner Bratzler Shear Force. Os níveis de proteína bruta não influenciaram as medidas objetivas de carcaça nem as do músculo Longissimus dorsi. Houve efeito significativo para peso e rendimento da paleta, com superioridade para o tratamento contendo 25% de proteína bruta. Nas análises químicas do músculo Longissimus dorsi, observou-se efeito significativo para extrato etéreo, cinzas e maciez. No sistema de alimentação e terminação de cordeiros Suffolk em creep feeding, a ração formulada com farelo de soja como fonte protéica deve ser balanceada com 25% de proteína bruta por diminuir o teor de gordura e melhorar a maciez da carne e o peso e rendimento da paleta, sem afetar as medidas objetivas da carcaça, os demais pesos e os rendimentos dos cortes.<br>The objective of this trial was to evaluate the effects of three concentrate protein levels (15, 20 or 25% CP) on measurements of carcass and Longissimus dorsi muscle, weights and yields of cuts, and chemical composition and tenderness of meat of Suffolk lambs in creep feeding. Fifteen single birth lambs were used in this study. Lambs were slaughtered when they reached a final body weight of 28 kg. After slaughter, carcasses were maintained in a refrigerator at 5ºC for 24 hours followed by measurements on the left half carcass done after separation of the commercial cuts. The Longissimus dorsi area was measured to obtain the loin eye area (LEA, cm2). Both left and right loins were frozen; the left was used for determination of chemical composition while the right for a tenderness test ("Warner Bratzler Shear Force"). Different concentrate crude protein levels did not affect carcass measurements as well as measurements on the Longissimus dorsi. However, significant differences among treatments were observed for weight and yield of shoulder clod with the highest values found on the 25% crude protein concentrate. Chemical analyses of Longissimus dorsi showed significant differences across treatments for ether extract, ash, and tenderness. It can be concluded that the diet containing soybean meal must be formulated to yield 25% of crude protein because it reduced the fat content and improved the tenderness of the meat. In addition, it also increased both weight and yield of shoulder clod with no changes on carcass measurements and weight and yields of the remaining cuts

Desempenho e características de carcaça de cordeiros alimentados em comedouros privativos recebendo rações contendo semente de girassol Performance and carcass traits of lambs fed diets containing sunflower seed in creep feeding

Avaliaram-se o desempenho e as características quali e quantitativas da carcaça de cordeiros alimentados com ração contendo semente de girassol. Utilizaram-se 16 cordeiros distribuídos aleatoriamente em um delineamento inteiramente casualizado com quatro tratamentos (0,00; 6,60; 13,20 ou 19,80% de semente de girassol na matéria natural), cada um com quatro repetições, totalizando 16 cordeiros. As dietas continham 2,65; 2,78; 2,89 e 2,93 Mcal/kg de energia metabolizável e 18,38; 18,75; 19,98 e 21,18% de proteína bruta, respectivamente, e foi fornecida ad libitum. Os cordeiros foram pesados a cada 14 dias e mantidos com as ovelhas até atingirem 28 kg, quando foram abatidos, após jejum de sólidos por 18 horas, para obtenção do peso vivo ao abate e registro do peso da carcaça quente e do conteúdo gastrintestinal, utilizados no cálculo do peso de corpo vazio. As carcaças foram mantidas por 24 horas em câmara frigorífica em temperatura de 5ºC para obtenção do peso de carcaça fria. Os níveis de semente de girassol na dieta não afetaram as características de desempenho dos cordeiros. No entanto, os pesos de carcaça quente e de carcaça fria; os pesos de pescoço, baixo, paleta, costela descoberta, costela, lombo; e os rendimentos comerciais de carcaça e costela descoberta, costela, lombo, paleta, pescoço e baixo sofreram efeito da adição da semente de girassol. O fornecimento de semente de girassol na dieta não influencia as características qualitativas e morfométricas da carcaça de cordeiros.<br>Performance and quantitative and qualitative carcass traits of lambs fed with diets containing sunflower seed were evaluated. Sixteen lambs were randomly distributed to a completely randomized design with four diets (0.00, 6.60, 13.20 or 19.80% of sunflower seed, % as fed), with 4 replications. The diets contained 2.65, 2.78, 2.89 and 2.93 Mcal / kg of metabolize energy and 18.38, 18.75, 19.98 and 21.18% crude protein, respectively, and was ad libitum fed. The lambs were weighed every 14 days and kept with the ewes until they reached 28 kg, when were slaughtered, after solid fasting for 18 hours, to obtain slaughter body weight and recording hot carcass weight and gastrointestinal content, used in the calculation of empty body weight. The carcasses were kept for 24 hours in a cold room temperature of 5ºC to obtain cold carcass weight. Sunflower seed levels in the diet did not affect the performance characteristics of lambs. However, the hot carcass weight and cold carcass weight, the weights of neck, low, shoulder, rib, thru rib, loin and carcass commercial yields and rib, thru rib, loin, shoulder, neck and low showed effect of sunflower seed addition. The addition of sunflower seed in the diet does not influence the qualitative and morphometric characteristics of carcass of lambs