Effect of Processing Method on Pasturization and Nitrogen Components of Broiler Litter and on Nitrogen Utilization by Sheep

Abstract

Various methods of processing broiler litter were evaluated. Treatments found to be effective for pasteurization were dry heating at 150 C for 20 min; autoclaving for 10 min or longer; dry heating at 150 C at depths of .6 or 2.5 cm following addition of 1 to 4 g of paraformaldehyde (PFA) per 100 g of litter; and ethylene oxide (ETO) fumigation for a minimum of 30 minutes. Uric acid nitrogen was lowered (P < .01) by dry heat, alone or in combination with PFA. Autoclaving and PFA addition followed by dry heat lowered (P < .01) NPN. Ammonia nitrogen was reduced (P < .01) by most of the pasteurizing treatments except autoclaving for 10 minutes. A metabolism trial was conducted with 18 wethers to study the relative effects of different litter processing methods on nitrogen utilization. Litter pasteurized by dry heating at a depth of .6 cm for 20 min, dry heating at a depth of 2.5 cm for 15 min after the addition of 2 g of PFA per 100 g of litter or fumigation with ETO at a depth of 15.2 cm for 60 min supplied 50% of the nitrogen in the respective rations. Method of processing had no significant effect on nitrogen utilization or apparent digestion coefficients. Ruminal ammonia nitrogen was higher (P < .05) for sheep fed dry heat than for those fed ethylene oxide treated litter. Acetic acid and total volatile fatty acid concentrations, expressed as µ moles/ml, were significantly (P < .05) higher for the sheep fed litter treated with dry heat plus PFA than for those fed Utter treated with dry heat without PFA.