Short chain nitrocompounds as a treatment of layer hen manure and litter; effects on in vitro survivability of Salmonella, generic E-coli and nitrogen metabolism

Abstract

The current study was conducted to assess the bactericidal effectiveness of several nitrocompounds against pathogens in layer hen manure and litter. Evidence from an initial study indicated that treatment of layer hen manure with 12mM nitroethane decreased populations of generic E. coli and total coliforms by 0.7 and 2.2 log(10) colony forming units (CFU) g(-1), respectively, after 24h aerobic incubation at ambient temperature when compared to untreated populations. Salmonella concentrations were unaffected by nitroethane in this study. In a follow-up experiment, treatment of 6-month-old layer hen litter (mixed with 0.4mL water g(-1)) with 44mM 2-nitroethanol, 2-nitropropanol or ethyl nitroacetate decreased an inoculated Salmonella typhimurium strain from its initial concentration (3 log(10) CFU g(-1)) by 0.7 to 1.7 log(10) CFU g(-1) after 6h incubation at 37 degrees C in covered containers. After 24h incubation, populations of the inoculated S. Typhmiurium in litter treated with 44mM 2-nitroethanol, 2-nitropropanol, ethyl nitroacetate or nitroethane were decreased more than 3.2 log(10) CFU g(-1) compared to populations in untreated control litter. Treatment of litter with 44mM 2-nitroethanol, 2-nitropropanol, ethyl nitroacetate decreased rates of ammonia accumulation more than 70\% compared to untreated controls (0.167 mu mol mL(-1) h(-1)) and loses of uric acid (< 1 mu mol mL(-1)) were observed only in litter treated with 44mM 2-nitropropanol, indicating that some of these nitrocompounds may help prevent loss of nitrogen in treated litter. Results warrant further research to determine if these nitrocompounds can be developed into an environmentally sustainable and safe strategy to eliminate pathogens from poultry litter, while preserving its nitrogen content as a nutritionally valuable crude protein source for ruminants.