Efeito de diferentes níveis de bicarbonato de sódio em dietas com bagaço de cana-de-açúcar auto-hidrolisado sobre a degradaçao in situ do milho e farelo de algodao

The objective of this work was to evaluate the buffering effect of sodium bicarbonate (NaHC03)' used in the levels of: 0, 0.7, 1.4 and 2.1 percent of dry matter, on the in situ degradation of corn and cottonseed meal. A diet with 60 percent autohidrolised sugar bagasse (BAH) and 40 percent of concentrate was used, plus urea, minerals and limestone. The rations was calculated to allow 300g of daily gain. After 20 days of adaptation to the treatment (levels of NaHC0(3)), 5g of each feed was incubated in the rumen of four bovines for 3, 6, 12, 24 and 48 hours, using naylon bag with size of 7,5 x 17,5 cm with pores of 36 micras. A ramdomized blocks design with four treatment (levels of NaHC03)) were used. The buffer affected the in situ dry matter degradation, whose means were 49.W 63, 10; 67,7 1; and 60,85 percent and 25.89; 30.88; 33.48 and; 3 1.02 percent for the corn and cottonseed meal, respectively. The level of 1.4 percent, of NaHC0(3) provided the highest value of' degradability, which did not differ from the 0.7 percent and 2. 1 percent levels, for the corn, The degradability of protein was not affected by the treatments.