Quality characteristics of Longissimus dorsi muscle from Bos indicus animals treated with vitamin D3

Muitas técnicas são empregadas para melhorar a maciez da carne de bovinos. A mais recente usa a vitamina D3, que tem importância na mobilização do cálcio e na ativação das proteases cálcio-dependentes (mi- e m-calpaína). Neste estudo, 36 machos castrados (Nelore) foram suplementados por via oral com quatro níveis de vitamina D3 (0, 3, 6 e 9 milhões de UI de vitamina D3 animal-1 dia-1) durante os 10 dias que antecederam o abate. Após o abate foram medidos a força de cisalhamento e perdas por cozimento (aos dias 1, 8 e 15 de maturação), pH, concentração de minerais no plasma sangüíneo e no músculo Longissimus dorsi, além de análise sensorial de amostras. Não houve (P >; 0.05) efeito da dose de vitamina D3 na concentração de minerais no plasma sangüíneo e no músculo, nas perdas por evaporação, e na suculência estimada pela análise sensorial. As menores perdas (totais e por gotejamento) foram em resposta à dose 6 × 10(6) UI an-1 dia-1 . A dose controle resultou na menor força de cisalhamento (FC), que tendeu a ser menor quanto maior o tempo de maturação. A dose 3 × 10(6) UI an-1 dia-1 afetou positivamente as características de maciez, sabor e aceitação global. A suplementação com elevadas doses de vitamina D3 não melhorou as características qualitativas do músculo Longissimus dorsi (contra-filé) de animais Nelore (Bos indicus).Among several techniques to improve beef tenderness, vitamin D3, important for calcium mobilization, has recently been developed as an alternative. It acts on the intracellular calcium-dependent proteases (mu- and m-calpain). Ten days prior to slaughter, 36 Nelore steers were fed 0, 3, 6 and 9 million IU of supplemental vitamin D3 (D3) per animal per day (an-1 d-1). Animals were slaughtered and tenderness (shear force), cooking losses (1, 8 and 15 days of aging), sensory evaluation, and minerals in blood plasma and muscle (Longissimus dorsi) were measured. There were no differences (P >; 0.05) among treatments for blood plasma and muscle mineral concentration, evaporation losses, and sensory juiciness. For drip and total loss, the smallest losses were for the 6 × 10(6) IU an-1 d-1 treatment. The control treatment resulted in lowest shear force and aging also tended to lower resistance to shearing. The 3 × 10(6) IU an-1 d-1 treatment had a positive effect on tenderness, flavor and overall palatability. High levels of supplemental D3 did not improve the quality characteristicsof Longissimus dorsi muscle from Bos indicus animals

Effect of physiological state and somatotropin on the response to lipolytic and antilipolytic signalling in ovine adipose tissue.

Foram utilizadas 24 ovelhas da raça Santa Inês para coleta de tecido adiposo, sendo 16 lactantes e 8 secas. Oito ovelhas lactantes foram tratadas in vivo com bST (160 mg, em duas doses em intervalo de 14 dias) iniciando a injeção subcutânea de hormônio no 13 o dia de lactação, sendo que os animais restantes receberam somente vitamina E. Outros 8 animais encontravam-se em período seco, para que fosse verificada também a diferença das taxas lipolíticas em diferentes estados fisiológicos. Foi verificada a hipótese de que ocorra uma atuação da ST através de mudança na resposta do sistema antilipolítico da proteína Gi ligada a receptores da adenosina. O tratamento com ST exógena aumentou o ganho de peso das ovelhas lactantes (P0,05). ISO stimulated lipolytic rate increased compared to basal and was higher for the adipose tissue from lactating ewes treated with bST (P<0,01).The lipolytic rate for adipose incubated with ADA was higher than basal for lactating ewes, with the greater response for the control. The ADA treated tissue from lactating ewes receiving bST showed intermediate lipolytic rates. Maximum lipolytic rate with ISO+ADA was also higher for lactating ewes treated with bST (P<0.01), and there was no difference between lactating and nonlactating ewes. The PIA effects were evaluated by the inhibition of ISO+ADA lipolysis, and adipose tissue from lactating ewes treated with bST showed a reduced response to PIA. The results demonstrate that in vivo somatotropin treatment increases maximal lipolytic rates stimulated by adrenergic agonist and decreases the antilipolytic effect of PIA in omental adipose tissue in ewes

Effect of physiological state and somatotropin on the response to lipolytic and antilipolytic signalling in ovine adipose tissue.

Foram utilizadas 24 ovelhas da raça Santa Inês para coleta de tecido adiposo, sendo 16 lactantes e 8 secas. Oito ovelhas lactantes foram tratadas in vivo com bST (160 mg, em duas doses em intervalo de 14 dias) iniciando a injeção subcutânea de hormônio no 13 o dia de lactação, sendo que os animais restantes receberam somente vitamina E. Outros 8 animais encontravam-se em período seco, para que fosse verificada também a diferença das taxas lipolíticas em diferentes estados fisiológicos. Foi verificada a hipótese de que ocorra uma atuação da ST através de mudança na resposta do sistema antilipolítico da proteína Gi ligada a receptores da adenosina. O tratamento com ST exógena aumentou o ganho de peso das ovelhas lactantes (P0,05). ISO stimulated lipolytic rate increased compared to basal and was higher for the adipose tissue from lactating ewes treated with bST (P<0,01).The lipolytic rate for adipose incubated with ADA was higher than basal for lactating ewes, with the greater response for the control. The ADA treated tissue from lactating ewes receiving bST showed intermediate lipolytic rates. Maximum lipolytic rate with ISO+ADA was also higher for lactating ewes treated with bST (P<0.01), and there was no difference between lactating and nonlactating ewes. The PIA effects were evaluated by the inhibition of ISO+ADA lipolysis, and adipose tissue from lactating ewes treated with bST showed a reduced response to PIA. The results demonstrate that in vivo somatotropin treatment increases maximal lipolytic rates stimulated by adrenergic agonist and decreases the antilipolytic effect of PIA in omental adipose tissue in ewes