Nitrogenous compounds balance and microbial protein synthesis in steers supplemented with sunflower crushed in partial replacement of soybean meal/Balanco de compostos nitrogenados e sintese de proteina microbiana em novilhos suplementados com torta de girassol em substituicao parcial ao farelo de soja

• Published in: Acta scientiarum. Animal sciences 2013-07, Vol.35 (3), p.281
• Main Authors: Lima, Hellen Leles, de Goes, Rafael Henrique de Tonissi Buschinelli, de Oliveira, Euclides Reuter, Gressler, Maria Gizelma de Menezes, Brabes, Kelly Cristina da Silva, Gabriel, Andrea Maria de Araujo
• Format: Article
• Language: Spanish
• Subjects: Amino acids; Four-wheel drive trucks; Protein synthesis; Soybeans; Urea
• ISSN: 1806-2636
• DOI: 10.4025/actascianimsci.v35i3.18654

Four steers in individual paddocks with Marandu grass (B. Brizantha) in 4x4 square design were used to evaluate sunflower crushed supplementation in pasture-grazing animals on nitrogen balance and microbial protein synthesis. Supplements at 6 g [kg.sup.-1] body weight comprised corn, soybean meal, and mineral and soybean meal substituted at proportions 0, 20, 40 and 60%. Diet contained averages 6.79, 6.96, 7.10 and 6.87% nitrogen respectively for substitution levels 0, 20, 40 and 60%. The inclusion of sunflower crushed (SC) increased nitrogen intake and fecal excretion of nitrogen while providing a positive balance. Animals' plasma urea concentration supplemented with SC was 28.13% lower than that of supplemented animals without SC. SC inclusion did not change allantoin concentration, purine derivatives, microbial nitrogen, crude microbial protein and microbial efficiency microbial, with mean rates totaling 150.98 mmol [day.sup.-1]; 158.06 mmol [day.sup.-1], 112.35 g [day.sup.-1], 702.18 g [day.sup.-1]; 146.41 crude protein (CP) microbial [kg.sup.-1] of TDN. Partial replacement of soybean meal by sunflower crushed improves nitrogen balance without altering microbial protein synthesis and excretion of urea and creatinine. Keywords: creatinine, microbial efficiency, plasma urea, purine derivatives, urea. Para se avaliar a suplementacao de torta de girassol em novilhos mantidos a pasto, sobre o balanco de nitrogenio e a sintese de proteina microbiana, foram utilizados quatro animais em piquetes com capim Marandu (B. Brizantha), em quadrado latino 4x4. Os suplementos foram fornecidos na quantidade de 6 g kg'1 de peso vivo dia'1; constituidos de milho, farelo de soja e mineral, sendo o farelo de soja substituido nas proporcoes de 0, 20, 40, e 60%. A dieta disponivel apresentava em media 6,79; 6,96; 7,10 e 6,87% de nitrogenio, para os niveis de substituicao de 0, 20, 40 e 60%. A inclusao da torta de girassol (TG) elevou o N ingerido e o N fecal, proporcionando balanco positivo. A concentracao plasmatica de ureia dos animais suplementados com TG foi 28,13% inferior aos animais suplementados sem TG. A inclusao de TG nao alterou a concentracao de alantoina, os derivados de purina, o nitrogenio microbiano, proteina bruta microbiana e eficiencia microbiana, apresentando valores medios de 150,98 mmol [dia.sup.-1]; 158,06 mmol [dia.sup.-1]; 112,35 g [dia.sup.-1]; 702,18 g [dia.sup.-1]; 146,41 proteina bruta microbiana [kg.sup.-1] NDT. A substituicao parcial do farelo d