Effects of adding various substrates to broiler litter before deep-stacking on nutrient composition, digestibility and recovery

摘要

Broiler litter was mixed with xylose and(or) soybean meal and deep-stacked at 21, 26 or 31% moisture for 7, 21 or 63 d to determine changes in composition and ruminal degradability of organic matter (OM) and nitrogen (N). Xylose decreased soluble N concentration at 7 and 21 d incubations. At 12 h of ruminal incubations, xylose decreased in vitro NH$sb3$-N release and in sacco N disappearance with soybean meal. Ruminal undegradable protein concentration may be increased by addition to deep-stacked broiler litter of xylose and soybean meal, containing amino acids susceptible to non-enzymatic browning reactions. Effects of xylose and soybean meal additions on indices of ruminal degradation of nitrogenous compounds were not markedly altered by moisture level or incubation length. Effects of mixing urea with broiler litter on composition and digestibility of various fibrous substrates in dacron bags placed for 3 or 9 wk at 36 or 72 cm from the surface of deep-stacks open or covered with plastic were determined. Urea decreased neutral detergent fiber (NDF) concentration in bermudagrass, wheat straw and rice straw, with small or nonsignificant changes noted for rice hulls and pine shavings. In vitro NDF digestibility at 48 h was increased by urea for bermudagrass and wheat straw; greater at 9 than at 3 wk for rice straw and 2 pine shavings. Urea addition to broiler litter before deep-stacking may improve nutritive value of some fibrous substrates for ruminants. Different types and levels of carbonaceous feedstuffs mixed with broiler litter were incubated in a broiler litter deep-stack for 3 or 9 wk to determine effects on nutrient composition, recovery and digestibility. Cereal grain addition alone had limited change in N recovery and loss of neutral detergent soluble OM (NDSOM). Roughages addition alone did not markedly change recoveries of N and NDF. Molasses addition alone decreased NDF recovery and increased N disappearance in situ and recoveries of N and NDSOM. Molasses addition with other substrates induced positive associative effects and the effects were varied with level of addition and incubation length.