Cinética digestiva e eficiência de síntese de proteína microbiana em novilhos alimentados com farelo de girassol e diferentes fontes energéticas
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Data
2006-02-01
Autores
Mendes, Rosália [UNESP]
Ezequiel, Jane Maria Bertocco [UNESP]
Galati, Rosemary Laís [UNESP]
Nascimento, Virgílio Franco do
Queiroz, Mário Adriano Ávila
Pereira, Expedita Maria de Oliveira [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Zootecnia
Resumo
Objetivou-se avaliar o efeito da substituição parcial do milho pela casca de soja e pelo farelo de gérmen de milho sobre a produção e eficiência de síntese de proteína microbiana e sobre as taxas de diluição e passagem ruminal. Foram utilizados três novilhos de corte, mestiços, canulados no rúmen e no duodeno, distribuídos em dois delineamentos em quadrado latino 3 x 3. As dietas experimentais, à base de silagem de milho (60%), apresentavam como fonte de proteína farelo de girassol e, como fonte de energia, milho (MI) ou sua substituição parcial pela casca de soja (CS) ou pelo farelo de gérmen de milho (FGM). Para o isolamento da massa microbiana, foram coletadas amostras de conteúdo ruminal às 3, 6, 9 e 12 horas após a alimentação. Utilizaram-se RNA como marcador microbiano e dicromato de sódio e Co-EDTA como indicadores das taxas de passagem e de diluição, respectivamente. A composição dos microrganismos ruminais não foi influenciada pelas dietas experimentais ou pelos horários de coleta. Não houve diferenças significativas no fluxo de matéria orgânica, carboidratos totais, nitrogênio e nitrogênio microbiano para o duodeno e na eficiência de síntese de proteína microbiana. As taxas de diluição foram semelhantes entre as dietas, com média de 13,4%/h. A taxa de passagem da silagem de milho mordentada foi menor, com tendência de menor taxa de passagem também para o farelo de girassol na dieta MI. A casca de soja e o farelo de gérmen de milho podem substituir parcialmente o milho, proporcionando ambiente ruminal adequado ao desenvolvimento da flora microbiana e conseqüente produção de proteína microbiana ruminal em novilhos confinados.
The objective of this trial was to evaluate the partial replacement of ground corn with soybean hulls or corn germ meal on ruminal microbial protein synthesis and efficiency and ruminal dilution and passage rates. Three crossbreed steers fitted with ruminal and duodenal cannulas were assigned to two 3 x 3 Latin squares. The experimental diets contained: corn silage (60%), sunflower meal and ground corn (GC diet) that was partially replaced with soybean hulls (SBH diet) or corn germ meal (CGM diet). Ruminal fluid was collected at 3, 6, 9, and 12 hours after feeding for isolation of ruminal microbes. RNA was used as the microbial marker while sodium dicromate and Co-EDTA were used as passage and dilution rate markers, respectively. Ruminal microbial composition was not affected by diets and time after feeding in the present trial. Moreover, duodenal flows of organic matter, total carbohydrates, nitrogen (N), and microbial N as well as microbial efficiency were all not significantly changed across diets. Fluid dilution rate also did not differ and averaged 13.4%/h among diets. Ruminal passage rate of mordant corn silage was lower and a trend for lower passage rate of sunflower meal on GC diet also was observed. Soybean hulls and corn germ meal can partially replace ground corn on diets for confined steers because they provided adequate ruminal environment for microbial growth and microbial protein synthesis.
The objective of this trial was to evaluate the partial replacement of ground corn with soybean hulls or corn germ meal on ruminal microbial protein synthesis and efficiency and ruminal dilution and passage rates. Three crossbreed steers fitted with ruminal and duodenal cannulas were assigned to two 3 x 3 Latin squares. The experimental diets contained: corn silage (60%), sunflower meal and ground corn (GC diet) that was partially replaced with soybean hulls (SBH diet) or corn germ meal (CGM diet). Ruminal fluid was collected at 3, 6, 9, and 12 hours after feeding for isolation of ruminal microbes. RNA was used as the microbial marker while sodium dicromate and Co-EDTA were used as passage and dilution rate markers, respectively. Ruminal microbial composition was not affected by diets and time after feeding in the present trial. Moreover, duodenal flows of organic matter, total carbohydrates, nitrogen (N), and microbial N as well as microbial efficiency were all not significantly changed across diets. Fluid dilution rate also did not differ and averaged 13.4%/h among diets. Ruminal passage rate of mordant corn silage was lower and a trend for lower passage rate of sunflower meal on GC diet also was observed. Soybean hulls and corn germ meal can partially replace ground corn on diets for confined steers because they provided adequate ruminal environment for microbial growth and microbial protein synthesis.
Descrição
Palavras-chave
corn germ meal, dilution rate, ruminal microbial, passage rate, soybean hulls, Casca de soja, farelo de gérmen de milho, microrganismos ruminais, taxa de diluição, taxa de passagem
Como citar
Revista Brasileira de Zootecnia. Sociedade Brasileira de Zootecnia, v. 35, n. 1, p. 264-274, 2006.