Efeito da somatotropina na hipertrofia das fibras musculares esqueléticas e precocidade reprodutiva de novilhas Nelore
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Data
2000-09-01
Autores
MOREIRA, PAULO SÉRGIO ANDRADE [UNESP]
Silveira, Antonio Carlos [UNESP]
Arrigoni, Mario de Beni [UNESP]
Costa, Ciniro [UNESP]
CHARDULO, LUIS ARTHUR LOYOLA [UNESP]
FURLAN, LUIZ ROBERTO [UNESP]
DAL PAI, VITALINO [UNESP]
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Editor
Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA)
Resumo
O trabalho objetivou avaliar o desempenho produtivo, precocidade sexual e hipertrofia das fibras musculares esqueléticas em resposta à aplicação de somatotropina bovina recombinante (rbST). Foram utilizadas 58 novilhas Nelore de sete meses de idade com peso vivo médio de 193 kg. O delineamento experimental foi inteiramente casualizado, em um esquema fatorial incompleto e dividido em duas fases experimentais. Na primeira fase, com duração de 150 dias, os animais foram divididos em dois grupos, de acordo com os níveis de rbST, 0 mg (controle) e 500 mg, a cada 28 dias. Na Fase II, os animais do grupo controle da Fase I foram divididos em 15 e 14 novilhas, que receberam 0 mg e 500 mg de rbST, respectivamente; os animais tratados com 500 mg na Fase I foram divididos em 15 e 14 novilhas e receberam 500 mg e 1.000 mg de rbST, respectivamente, com intervalos de 28 dias, e dieta em regime de pastejo, durante 180 dias. Foram retirados fragmentos do músculo semitendinosus para análise das fibras, no início e final da Fase I. Os animais foram pesados a cada 28 dias. Os resultados mostraram que não houve diferença significativa (p>0,05) entre os tratamentos quanto ao ganho de peso e quanto à precocidade sexual. Quanto ao diâmetro das fibras, os animais que receberam rbST tiveram um aumento significativo (p<0,01) tanto nas fibras de contração lenta quanto nas fibras de contração rápida em relação aos animais-controle.
The objective of this study was to determine the effects of recombinant bovine somatotropin (rbST) on performance, reproductive precocity and hyperthrophy in muscle fibers in Nelore heifers. In the present study, 58 heifers seven months of age weighing 193 kg were used. The experimental design was completely randomized and divided in two phases. In the first phase of 150 days, the levels of rbSt were 0 mg and 500 mg at 28 day intervals. In the phase II, each group of phase I was divided in two new groups and the levels of rbST were 0 mg and 500 mg for the control group, and 500 mg and 1,000 mg for 500 mg group of phase I, at 28 day intervals. Diet was exclusively pasture by 180 days. Biopsy of semitendinosus muscle was done for analysis of fibers at the beginning and at the end of phase I. The animals were weighed monthly (28 days). Results showed no significative differences (p>0.05) among treatments for gain of weight and for sexual precocity. For SO (slow oxidative), FOG (fast oxidative glycolitic) and FG (fast glycolitic) muscle fiber diameter a significative difference (p<0.01) with higher values for rbST treated heifers was observed.
The objective of this study was to determine the effects of recombinant bovine somatotropin (rbST) on performance, reproductive precocity and hyperthrophy in muscle fibers in Nelore heifers. In the present study, 58 heifers seven months of age weighing 193 kg were used. The experimental design was completely randomized and divided in two phases. In the first phase of 150 days, the levels of rbSt were 0 mg and 500 mg at 28 day intervals. In the phase II, each group of phase I was divided in two new groups and the levels of rbST were 0 mg and 500 mg for the control group, and 500 mg and 1,000 mg for 500 mg group of phase I, at 28 day intervals. Diet was exclusively pasture by 180 days. Biopsy of semitendinosus muscle was done for analysis of fibers at the beginning and at the end of phase I. The animals were weighed monthly (28 days). Results showed no significative differences (p>0.05) among treatments for gain of weight and for sexual precocity. For SO (slow oxidative), FOG (fast oxidative glycolitic) and FG (fast glycolitic) muscle fiber diameter a significative difference (p<0.01) with higher values for rbST treated heifers was observed.
Descrição
Palavras-chave
hormônios de crescimento animal, reprodução sexual, precocidade, ganho de peso, gado de corte, produção animal, animal growth hormones, sexual reproduction, precocity, weight gain, beef cattle, animal production
Como citar
Pesquisa Agropecuária Brasileira. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) Informação TecnológicaPesquisa Agropecuária Brasileira, v. 35, n. 9, p. 1853-1860, 2000.