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

Authors: RUIZ-BARRERA, OSCAR - Universidad Autonoma De Chihuahua; Anderson, Robin; Hume, Michael; CORRALES-MILLAN, JONATAN - Universidad Autonoma De Chihuahua; CASTILLO-CASTILLO, YAMICELA - University Of Tamaulipas; CORRAL-LUNA, AGUSTIN - Universidad Autonoma De Chihuahua; GUEVARA-VALDEZ, JOSE - Universidad Autonoma De Chihuahua; SALINAS-CHAVIRA, JAIME - University Of Tamaulipas; RODRIGUEZ-MUELA, CARLOS - Universidad Autonoma De Chihuahua; ARZOLA-ALVAREZ, CLAUDIO - Universidad Autonoma De Chihuahua

Submitted to: Journal of Environmental Science and Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2016
Publication Date: 9/14/2016
Publication URL: http://handle.nal.usda.gov/10113/63176
Citation: Ruiz-Barrera, O., Anderson, R.C., Hume, M.E., Corrales-Millan, J., Castillo-Castillo, Y., Corral-Luna, A., Guevara-Valdez, J.L., Salinas-Chavira, J., Rodriguez-Muela, C., Arzola-Alvarez, C. 2016. 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. Journal of Environmental Science and Health. 52(1):23-29. doi: 10.1080/03601234.2016.1224698.

Interpretive Summary: Poultry litter is a byproduct produced in large amounts by intensive poultry production systems. Disposal of this waste product can be environmentally challenging for producers, as repeated application to land as fertilizer can cause excessive accumulations of phosphorous, potassium, and nitrogen into the soil or watershed. Poultry litter also contains appreciable amounts of its nitrogen as a chemical called uric acid, which makes it an excellent dietary crude protein supplement for cattle whose gut bacteria can transform and thus upgrade the nitrogen in uric acid into a nutritious, high quality protein. Poultry litter can contain high numbers of pathogenic bacteria such as Salmonella, E. coli, and Campylobacter however, and thus it will require prior treatment to kill these as well as other pathogenic bacteria before it can be safely fed to cattle. The current study was conducted to assess the antimicrobial effectiveness of a class of chemicals referred to as nitrocompounds against pathogens in poultry litter. Evidence from an initial study indicated that treatment of litter with a chemical called nitroethane decreased populations of generic E. coli and total coliforms by as much as 100-fold. In a follow up experiment, treatment of poultry litter with related chemicals called 2-nitroethanol, 2-nitropropanol, or ethyl nitroacetate cause as much as 1000- fold decreases of Salmonella when compared to untreated litter. Treatment of the litter with 2-nitroethanol, 2-nitropropanol, or ethyl nitroacetate also decreased rates of ammonia production by more than 70% compared to untreated litter, 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. Ultimately, this research may yield a safe, environmentally compatible, and sustainable technology for recycling nutrients contained in poultry litter consistent with good agricultural practice. This technology can help both poultry farmers and cattle ranchers produce more food at less cost and with a lower environmental footprint.

Technical Abstract: Layer hen manure and litter contain appreciable amounts of uric acid, which makes these good crude protein sources for ruminants. Rumen microbial populations can upgrade the nitrogen in uric acid into high quality microbial protein of nutritional value to the host. Layer hen manure and litter can contain high numbers of Salmonella, E. coli, and Campylobacter however, and thus require prior treatment to kill these as well as other pathogenic bacteria in order to reduce risks of infection to ruminants and subsequent contamination of the foods they produce. 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 12 mM nitroethane decreased populations of generic E. coli and total coliforms by 0.7 and 2.2 log10 colony forming units (CFU)/g, respectively, after 24 h 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 0.4 mL water/g) with 44 mM 2-nitroethanol, 2-nitropropanol, or ethyl nitroacetate decreased an inoculated Salmonella Typhimurium strain from its initial concentration (3 log10 CFU/g) by 0.7 to 1.7 log10 CFU/g after 6 h incubation at 37C in covered containers. After 24 h incubation, populations of the inoculated S. Typhmiurium in litter treated with 44 mM 2-nitroethanol, 2-nitropropanol, or ethyl nitroacetate or nitroethane were decreased more than 3.2 log10 CFU/g compared to populations in untreated control litter. Treatment of litter with 44 mM 2-nitroethanol, 2-nitropropanol, or ethyl nitroacetate decreased rates of ammonia accumulation more than 70% compared to untreated controls (0.167 µmol/mL per h) and losses of uric acid (< 1 µmol/mL) were observed only in litter treated with 44 mM 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.