ADDITION OF CONDENSED TANNIN SOURCES TO BROILER LITTER BEFORE DEEP-STACKING

Different sources and levels of condensed tannins were thoroughly mixe d (M) or covered (C) with broiler litter in plastic vessels fitted wit h a dacron top. Containers were placed in a deep-stack for 3 or 9 wk t o determine effects on constituent concentrations, recoveries and in s itu ruminal disappearances. Added substrates were commercial vegetable extract (VE; quebracho) peanut skins (PS), bird-resistant sorghum gra in (BS) and regular sorghum grain (S), with condensed tannin (catechin equivalents) concentrations of 68.4, 24.7, 0.6 and 0.0%, respectively . Levels (total dry matter basis) were 0, 0.04, 0.09, 0.17, 0.35, 1.3, 2.6, 5.1 and 10.3% VE; 0, 3.6, 7.1, 14.2 and 28.4% PS; and 0, 5, 10, 20 and 40% BS and S. Condensed tannin recovery for VE [120, 113, 105, 98, 63, 27, 18, 12 and 10% for M and 125, 118, 107, 84, 59, 37, 23, 20 and 23% for C at 3 wk (SE 2.8); 87, 74, 66, 61, 44, 22, 16, 9 and 11% at 9 wk (SE 3.3) with 0, 0.04, 0.09, 0.17, 0.35, 1.3, 2.6, 5.1 and 10 .3% VE, respectively], PS [139, 29, 18, 14 and 20% for M and 126, 37, 27, 25 and 46% for C at 3 wk (SE 4.9); 52, 21, 12, 9 and 6% for M and 91, 23, 14, 10 and 17% for C at 9 wk (SE 4.9) with 0, 3.6, 7.1, 14.2 a nd 28.4% PS,respectively] and BS [135, 99, 109, 75 and 50% at 3 wk and 97, 88, 88, 68 and 48% at 9 wk (SE 5.1) with 0, 5, 10, 20 and 40% BS, respectively] generally was less for 9 vs 3 wk of deep-stacking and d ecreased with increasing level of condensed tannin source. Addition of condensed tannin sources did not markedly alter concentrations of nit rogen fractions, recoveries of organic matter or nitrogen or in situ d ry matter ol nitrogen disappearances. In conclusion, addition of conde nsed tannin sources to broiler litter before deep-stacking decreased r ecovery of assayable condensed tannins, with effects varying with leve l and method of addition.