Use of antibiotics in subtherapeutic doses as growth-promoting feed additives for animal production is widespread in the U.S. and throughout the world. Previous studies by our research group concluded that size fractionation of poultry (broiler) litter followed by storage facilitated reutilization of litter as a soil amendment or bedding supplement. However, litter microbial contamination, including antibiotic-resistant populations, and accumulation of metals and other elements may limit litter reutilization. Litter from four broiler houses was separated into a fine fraction for use as a soil amendment, and a coarse fraction for reutilization as a bedding supplement in growing subsequent flocks of broilers. Fractions and whole litter were stored in indoor piles simulating farm storage conditions for 4 mo with periodic analysis for metals, other elements, and culturable bacteria (including total and fecal coliform, Aeromonas hydrophila, Pseudomonas aeruginosa, Yersinia enterocolitica, and Campylobacter jejuni). Representative bacterial isolates were tested for their sensitivity to 12 common antibiotics (ampicillin, bacitracin, cephalothin, erythromycin, gentamicin, kanamycin, nalidixic acid, neomycin, penicillin, streptomycin, sulfisoxazole, and tetracycline) using the Kirby-Bauer technique. Pathogens and indicator bacteria tested were found to be resistant to multiple antibiotics. Data suggest that microbial contamination of litter should be reduced or eliminated prior to reutilization to minimize environmental health risks related to transfer of antibiotic-resistant bacteria to humans or other animals.

Passing poultry litter through a fine sieve (<0.83 mm) generates a fine fraction that is higher in N concentration than the whole litter and cheaper to transport per unit of N. This fine fraction can be pelletized to facilitate handling, but changing the physical characteristics of the litter may change the amount of N loss or the rate at which N mineralizes. The objective of this work was to evaluate the effect of physical characteristics of the fine poultry litter fraction (pelletized or fine particles) on net N and C mineralization, NH3 volatilization, and denitrification resulting from surface applications of the fine fraction to Cecil loamy sand (clayey, kaolinitic, thermic Typic Kanhapludult) and Dothan loamy sand (fine‐loamy, siliceous, thermic Plinthic Kandiudulf) soils. The soils were adjusted to 52% water‐filled porosity, treated with either pelletized or fine‐particle poultry litter at 30.7 g N m−2, and incubated at 25 °C for 35 d. Humidified air was circulated over each sample (15 chamber volumes min−1) and the NH3 evolved was trapped in 0.025 M H2SO4. Inorganic N contents and rates of denitrification and respiration were measured at 1, 3, 7, 14, 21, and 35 d after application. The physical characteristics of the litter did not affect total amounts of net N mineralized and NH3 volatilized in 35 d. However, total denitrification losses were significantly higher for pelletized (6.2% of the applied N in Dothan and 7.9% in Cecil) than for fine‐particle litter (0.2% in Dothan and 0.8% in Cecil). Thus, surface application of pelletized litter may result in increased denitrification losses compared with fine‐particle litter.

While several studies have shown that the addition of animal manures to soil can increase N20 and CO 2 emissions, limited information is available on the effect that manure physical characteristics can have on these emissions. This study compared N20 and CO2 emissions from poultry litter incorporated as pellets (5.5 mm OD, 7 mm long) or fine particles (<0.83 mm) into Cecil soil samples. The soil-litter mixture was packed in acrylic plastic cylinders and adjusted to 55 or 90 % water-filled porosity (WFP). The cylinders were placed inside jars that were sealed and placed in an incubator at 25°C for 35 d, with periodic air samplings conducted for N20 and CO2 analyses. At 55 % WFP, cumulative emission of CO2 was similar for both litter types, but cumulative emission of N20 was slightly higher for pelletized (6.8 % of applied N) than for fine-particle litter (5.5 %). In contrast, at 90 % WFP, cumulative emission of N20 was larger for fine-particle litter (3.4 % of applied N) than for pelletized litter (1.5 %). These results indicate that the effect of poultry litter physical characteristics on N20 emissions from incorporated applications can be expected to vary depending on the soil water regime.

No abstract

An experiment was conducted to compare the proximate composition of particulate matter recovered from poultry processing wastewater (PPW) generated by broiler slaughter plants. Poultry processing wastewater is the cumulative wastewater stream generated during the processing of poultry following primary and secondary physical screening (typically to 500 mum) that removes gross offal. Composite samples of PPW from 3 broiler slaughter plants (southeast United States) were collected over 8 consecutive weeks. All 3 broiler slaughter plants process young chickens with an average live weight of 2.0 kg. At each plant, a single 72-L composite sample was collected using an automatic sampler programmed to collect 1 L of wastewater every 20 min for 24 h during one normal processing day each week. Each composite sample was thoroughly mixed, and 60 L was passed through a series of sieves (2.0 mm, 1.0 mm, 500 mum, and 53 mum). The amount of particulate solids collected on the 2.0 mm, 1.0 mm, and 500 mum sieves was insignificant. The solids recovered from the 53-mum sieve were subjected to proximate analysis to determine percent moisture, fat, protein, ash, and fiber. The average percentages of fat, protein, ash, and fiber for all samples on a dry-weight basis were 55.3, 27.1, 6.1, and 4.1, respectively. Fat made up over half of the dry-weight matter recovered, representing PPW particulate matter between 500 and 53 mum. Despite the variation in number of birds processed daily, further processing operations, and number and type of wastewater screens utilized, there were no significance differences in percentage of fat and fiber between the slaughter plants. There were significant differences in percent protein and ash between the slaughter plants.