Uses and management of poultry litter

Assessing Class 1 Integron Presence in Poultry Litter Amended with Wood Biochar and Wood Vinegar

Class 1 integrons are mobile genetic elements that facilitate the spread of antibiotic resistance genes among bacteria. The use of prophylactic antibiotics has resulted in the rise of antibiotic resistance genes accumulating in a wide range of settings, including poultry houses and the agricultural fields where poultry litter is applied as a fertilizer. Biochar and wood vinegar are forest products wastes that have generated increasing attention as additives to agricultural soils. The objectives of this study were to observe the prevalence of class 1 integrons in poultry litter blended with biochar and wood vinegar over time and to verify a modified class 1 integron screening assay. Poultry litter blends were sampled and screened for class 1 integrons using polymerase chain reaction, and 80 products, 79 of which showed positive, were sent for DNA sequencing. The GenBank® BLAST database was used to verify the presence of the class 1 integron-integrase gene (intI1). There was no change in prevalence over time in poultry litter blends. Out of 79 PCR products that were intI1 positive, 78 showed at least 95% sequence identity to intI1 encoding bacteria and 64 showed at least 97% sequence identity. This indicates that this method was effective for conducting baseline surveillance of class 1 integrons in poultry litter and poultry litter-blended biochar and/or wood vinegar. Most significantly, class 1 integron prevalence did not decrease over time, further supporting the recalcitrance of these elements and the need for improved monitoring systems.

Wheat litter and feed with aluminosilicates for improved growth and meat quality in broiler chickens

BACKGROUND

Natural minerals have many beneficial properties in poultry production, taking into account production as well as hygiene, health, safety, and quality of broiler meat. The aim of the study was to evaluate the effect of aluminosilicates in feed and litter on the growth performance and meat quality in chickens. Aluminosilicates, including halloysite and zeolite, could be a good alternative for synthetics, as a good solution for the environment in line with the current trends.

METHODS

Five-hundred male Ross 308 chickens were managed in 5 groups (10 replicates/group): LITTER: 1, control; 2, 0.95 kg/m2 of halloysite; 3, 0.475 kg/m2 of halloysite and 0.475 zeolite; 4, 0.95 kg/m2 of zeolite; 5, 0.25 kg/m2of halloysite and 0.7 kg/m2 of zeolite. FEED: groups 2-5, halloysite and zeolite addition (25:75 ratio; 0.5-2%). Growth performance (body weight and feed indicators), carcass, and meat quality (pH, colour, water-holding capacity, chemical composition of muscles) were recorded. The experimental setup, where the aluminosilicate additives were applied simultaneously, was proposed and approved by experts after pilot testing and on the basis of extensive literature where feed or litter additives were tested.

RESULTS

Body weight and its gain were higher in groups 3 and 4 than in 1, and feed intake was higher in 4. The weight of the carcass and some of its components, including muscles and skin with subcutaneous fat, were higher in 2-4. Water loss from leg muscles was lower in 4. The content of protein in muscles was significantly higher in 3. The addition of aluminosilicates in feed and litter had a positive effect on the growth performance and some traits of carcasses and meat quality, especially in group 3. Halloysite and zeolite can be used in feed and litter (especially 0.475 kg/m2 for each mineral in the wheat litter).

Particulate matter emissions during field application of poultry manure - The influence of moisture content and treatment

Along with industry and transportation, agriculture is one of the main sources of primary particulate matter (PM) emissions worldwide. Bioaerosol formation and PM release during livestock manure field application and the associated threats to environmental and human health are rarely investigated. In the temperate climate zone, field fertilization with manure seasonally contributes to local PM air pollution regularly twice per year (spring and autumn). Measurements in a wind tunnel, in the field and computational fluid dynamics (CFD) simulations were performed to analyze PM aerosolization during poultry manure application and the influence of manure moisture content and treatment. A positive correlation between manure dry matter content (DM) and PM release was observed. Therefore, treatments strongly increasing the DM of poultry manure should be avoided. However, high manure DM led to reduced microbial abundance and, therefore, to a lower risk of environmental pathogen dispersion. Considering the findings of PM and microbial measurements, the optimal poultry manure DM range for field fertilization was identified as 50-70%. Maximum PM₁₀ concentrations of approx. 10 mg per m³ of air were measured during the spreading of dried manure (DM 80%), a concentration that is classified as strongly harmful. The modeling of PM aerosolization processes indicated a low health risk beyond a distance of 400 m from the manure application source. The detailed knowledge about PM aerosolization during manure field application was improved with this study, enabling manure management optimization for lower PM aerosolization and pathogenic release into the environment.

Effects of Loblolly Pine Biochar and Wood Vinegar on Poultry Litter Nutrients and Microbial Abundance

Biochar, wood vinegar, and poultry litter are waste streams that can be utilized as soil amendments and fertilizers. However, poultry litter releases several pollutants through nutrient leaching and carries heavy microbial loads, including potential human pathogens. Improving nutrient retention and reducing microbial load in poultry litter may help protect environmental and human health and improve its value as a soil amendment. The objectives of this study were to determine how blending varying proportions of loblolly pine (Pinus taeda L.) biochar, wood vinegar, and poultry litter affected nutrient profiles and microbial abundance over time. Biochar inclusion rates were 0%, 5%, 10%, and 20%, and wood vinegar was applied at 2% w/w. Samples were taken at Day 0, 57, and 112 to measure nitrogen, phosphorus, potassium, pH, total fungi, and total bacteria. Nutrient levels generally decreased with increasing biochar level; however, biochar inclusion rates of 10% and 20% retained nitrogen and phosphorus and exhibited improved physical properties. Overall, adding wood vinegar decreased nutrient concentrations and showed a biocidal effect for bacteria and fungi. Bacteria and fungi showed different relationships with biochar inclusion rates, with fungi preferring higher biochar inclusion rates and bacteria flourishing at lower biochar inclusion rates.

Improving the Properties of Degraded Soils from Industrial Areas by Using Livestock Waste with Calcium Peroxide as a Green Oxidizer

Over the past years, the treatment and use of livestock waste has posed a significant problem in environmental engineering. This paper outlines a new approach to application of calcium peroxide (CaO₂) as a green oxidizer and microbiocidal agent in the treatment of poultry manure. It also presents the application of pretreated waste in improvement of degraded soils in industrial areas. The CCD (Central Composite Design) and RSM (Response Surface Methodology) were employed for optimizing the process parameters (CaO₂ concentration 1.6–8.4 wt %, temperature 5.2–38.8 °C and contact time 7–209 h). The analysis of variance (ANOVA) was used to analyze the experimental results, which indicated good fit of the approximated to the experimental data (R² = 0.8901, R²_adj = 0.8168). The amendment of CaO₂ in optimal conditions (8 wt % of CaO_2, temperature 22 °C and contact time 108 h) caused a decrease in bacteria Escherichia coli (E. coli) in poultry manure from 8.7 log₁₀ CFU/g to the acceptable level of 3 log₁₀ CFU/g. The application of pretreated livestock waste on degraded soils and the studies on germination and growth of grass seed mixture (Lollum perenne—Naki, Lollum perenne—Grilla, Poa pratensis—Oxford, Festuca rubbra—Relevant, Festuca rubbra—Adio and Festuca trachypylla—Fornito) showed that a dose of 0.08 g of CaO₂ per 1 gram of poultry manure induced higher yield of grass plants. The calculated indicators for growth of roots (GFR) and shoots (GFS) in soils treated with poultry manure were 10–20% lower compared to soils with amended CaO₂. The evidence from this study suggests that CaO₂ could be used as an environmentally friendly oxidizer and microbiocidal agent for livestock waste.

Determination of five antimicrobial families in droppings of therapeutically treated broiler chicken by high-performance liquid chromatography-tandem mass spectrometry

Antimicrobials are currently used in poultry for disease treatment. However, their excretion in bird feces may contaminate the environment. Considering this, the objective of this work was to quantify antimicrobials residues concentrations in therapeutically treated broiler chicken droppings throughout the post-treatment period. For this aim a multiresidue method using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was validated. Forty-eight male broiler chickens were distributed and treated with commercial formulations of 5 different antimicrobials. Results showed that oxytetracycline and 4-epi-oxytetracycline, presented the highest concentrations during all sampling period, detecting concentrations of 1471.41 µg kg⁻¹ at the last sampling point (day 22 post-treatment). Florfenicol, tylosin, enrofloxacin, and ciprofloxacin were eliminated and detected in treated chicken droppings until d 18 post-treatment. Sulfachloropyridazine decrease gradually during post-treatment period until day 30. Results demonstrate that studied antimicrobials in treated chicken droppings were eliminated for prolonged periods, therefore becoming a significant route of residues dissemination into the environment.

Detection of Antimicrobial Residues in Poultry Litter: Monitoring a Risk through a Selective and Sensitive HPLC-MS/MS Method

Simple Summary

After administration of antimicrobials, poultry excrete significant concentrations of antimicrobials through their droppings, which accumulate in the litter where poultry are housed. Poultry litter, which consists mainly of wood shavings, feathers, and droppings, is widely used as an agricultural fertilizer worldwide. The period that antimicrobials persist in agricultural soils could present various environmental and public health concerns. Thus, in this research, a method to identify different families of antimicrobials in poultry litter was developed. Results show that HPLC–MS/MS can reliably detect nine different compounds from three families of antimicrobials. This method was used to identify antimicrobials from commercial poultry flocks, providing a valuable and specific tool to monitor these residues in poultry litter prior to its use as an agricultural fertilizer.

Abstract

Tetracyclines, sulphonamides, and quinolones are families of antimicrobials (AMs) widely used in the poultry industry and can excrete up to 90% of AMs administrated, which accumulate in poultry litter. Worryingly, poultry litter is widely used as an agriculture fertilizer, contributing to the spread AMs residues in the environment. The aim of this research was to develop a method that could simultaneously identify and quantify three AMs families in poultry litter by high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS). Samples of AMs free poultry litter were used to validate the method according to 657/2002/EC and VICH GL49. Results indicate that limit of detection (LOD) ranged from 8.95 to 20.86 μg kg⁻¹, while limits of quantitation (LOQ) values were between 26.85 and 62.58 µg kg⁻¹ of tetracycline, 4-epi-tetracycline, oxytetracycline, 4-epi-oxytetracycline, enrofloxacin, ciprofloxacin, flumequine, sulfachloropyridazine, and sulfadiazine. Recoveries obtained ranged from 93 to 108%. The analysis of field samples obtained from seven commercial poultry flocks confirmed the adequacy of the method since it detected means concentrations ranging from 20 to 10,364 μg kg⁻¹. This provides us an accurate and reliable tool to monitor AMs residues in poultry litter and control its use as agricultural fertilizer.

Factors Influencing the Persistence of Salmonella Infantis in Broiler Litter During Composting and Stabilization Processes and Following Soil Incorporation

Broiler litter (BL), a by-product of broiler meat production, is frequently contaminated with Salmonella and other zoonotic pathogens. To ensure the safety of crop production chains and limit pathogen spread in the environment, a pre-treatment is desired before further agricultural utilization. The objective of this study was to characterize the effect of physico-chemical properties on Salmonella persistence in BL during composting and stabilization and following soil incorporation, toward optimization of the inactivation process. Thirty-six combinations of temperature (30, 40, 50, and 60°C), water content (40, 55, and 70%; w/w), and initial pH (6, 7, and 8.5) were employed in static lab vessels to study the persistence of Salmonella enterica serovar Infantis (S. Infantis; a multidrug-resistant strain) during incubation of artificially-inoculated BL. The effect of aeration was investigated in a composting simulator, with controlled heating and flow conditions. Temperature was found to be the main factor significantly influencing Salmonella decay rates, while water content and initial pH had a secondary level of influence with significant effects mainly at 30 and 40°C. Controlled simulations showed faster decay of Salmonella under anaerobic conditions at mesophilic temperatures (<45°C) and no effect of NH3 emissions. Re-wetting the BL at mesophilic temperatures resulted in Salmonella burst, and led to a higher tolerance of the pathogen at increased temperatures. Based on the decay rates measured under all temperature, water content, and pH conditions, it was estimated that the time required to achieve a 7 log10 reduction in Salmonella concentration, ranges between 13.7–27.2, 6.5–15.6, 1.2–4.7, and 1.3–1.5 days for 30, 40, 50, and 60°C, respectively. Inactivation of BL indigenous microbial population by autoclaving or addition of antibiotics to which the S. Infantis is resistant, resulted in augmentation of Salmonella multiplication. This suggests the presence of microbial antagonists in the BL, which inhibit the growth of the pathogen. Finally, Salmonella persisted over 90 days at 30°C in a Vertisol soil amended with inoculated BL, presumably due to reduced antagonistic activity compared to the BL alone. These findings are valuable for risk assessments and the formulation of guidelines for safe utilization of BL in agriculture.

Toxic Metals in Broccoli by Combined Use of Acidity Correctives and Poultry Litter Under Mountain Tropical Conditions

The current study was developed to evaluate agronomic efficiency and food security of isolated or simultaneous use of two residues-steel slag and fresh or composted poultry litter-in the cultivation of broccoli (Brassica oleracea var. italica). The composition and contribution of toxic and potentially toxic metals by different treatments and contents, translocation, and accumulation of Pb, Cd, Cu, Fe, Mn, and Zn in different plant organs were analyzed. Then, risks to human health associated with consumption of inflorescences were based on the indices of estimated daily intake, noncarcinogenic target hazard quotient, total hazard index (THI), and carcinogenic risk factor (CR), considering adults and children. Steel slag was similar to limestone in terms of the corrective effect of acidity and, despite containing toxic metals, it did not contribute to their higher translocation to inflorescences. Composting favored the concentrations of Pb, Cu, and Zn in poultry litter. The combined use of steel slag and fresh poultry litter and, mainly, composted poultry litter, favored absorption and translocation of Pb for inflorescences, that is, 60.37% and 66.13% of all Pb absorbed, respectively. Consumption of inflorescences from these treatments resulted in the critical THI values of 1.03 and 1.52, respectively, with Pb and Cd being the metals that mostly contributed to the risk. The registered CR was higher than the threshold level of 10^-6. The use of steel slag associated with poultry litter favors contamination of broccoli inflorescences and increases risks to human health due to their consumption.

Risk in the circular food economy: Glyphosate-based herbicide residues in manure fertilizers decrease crop yield

Glyphosate-based herbicides (GBHs) are the most frequently used herbicides globally. They were launched as a safe solution for weed control, but recently, an increasing number of studies have shown the existence of GBH residues and highlighted the associated risks they pose throughout ecosystems. Conventional agricultural practices often include the use of GBHs, and the use of glyphosate-resistant genetically modified crops is largely based on the application of glyphosate, which increases the likelihood of its residues ending up in animal feed. These residues persist throughout the digestive process of production animals and accumulate in their excretion products. The poultry industry, in particular, is rapidly growing, and excreted products are used as plant fertilizers in line with circular food economy practices. We studied the potential effects of unintentional glyphosate contamination on an agronomically important forage grass, meadow fescue (Festuca pratensis) and a horticulturally important strawberry (Fragaria x vescana) using glyphosate residues containing poultry manure as a plant fertilizer in a common garden experiment. Glyphosate in the manure decreased plant growth in both species and vegetative reproduction in F. x vescana. Furthermore, our results indicate that glyphosate residues in organic fertilizers might have indirect effects on sexual reproduction in F. pratensis and herbivory in F. x vescana because they positively correlate with plant size. Our results highlight that glyphosate can be unintentionally spread via organic fertilizer, counteracting its ability to promote plant growth.

Performance and Meat Quality of Broiler Chickens Reared on two Different Litter Materials and at two Stocking Densities

1. This study evaluated the performance and meat quality of broiler chickens reared on two litter materials and at two stocking densities.2. The chicks were allotted in a completely randomised design in a 2 × 2 factorial arrangement with two litter materials (wood shavings or rice straw) and two stocking densities (24 or 30 kg/m²), with six replicates per treatment. Broiler performance, carcase yield, prime cuts, blood plasma proteins, the enzymes alanine aminotransferase and aspartate aminotransferase, edible viscera, immune organs, intestine weight and length, abdominal fat, breast meat colour, pH, weight loss by defrosting, weight loss by cooking and shear force were evaluated.3. The density of 24 kg/m² positively influenced feed consumption and weight gain. The type of litter had a positive influence on feed conversion, with a lower value for birds raised on wood shavings.4. Breast production was improved in birds reared at a density of 24 kg/m² when compared to birds reared at a density of 30 kg/m². The rice straw bedding negatively affected abdominal fat (resulting in higher percentages) when compared to birds reared on wood shavings.5. The types of litter affected the enzyme aspartate aminotransferase in birds raised on wood shavings, although these values were not increased to the point of influence on the physiological functions of broilers.6. The colour of the breast meat, pH, temperature, weight loss after thawing or cooking, shear force, cholesterol, triglycerides, albumin, total proteins, glucose or alanine aminotransferase content were not influenced by the stocking densities or bedding.7. The use of wood shavings as poultry bedding at a stocking density of 24 kg/m²resulted in the best performance for broiler chickens at 42 days of age.

Identification of Phytotoxic Levels of Copper and Nickel in Commercial Organic Soil Amendments Recycled from Poultry Farms and Municipal Wastes

Commercial-scale recycling of agricultural and municipal wastes into organic soil amendments facilitates safe disposal of waste and reduces environmental contamination. However, phytotoxicity of commercial organic amendments to crops is a major concern to farmers. Consistent with this, commercial chicken manure and Milorganite (recycled from municipal waste) were found to be phytotoxic. Chicken manure aqueous extract contains 10.8 ppm Cu and 0.7 ppm Ni. The level of Cu and Ni in Milorganite is lower. The current study identified an aqueous solution containing 5 ppm Cu, lower than in chicken manure aqueous extract, was highly phytotoxic to mustard seeds germination. Therefore, phytotoxicity of chicken manure is in part due to Cu. An aqueous solution containing 1 ppm Ni was not phytotoxic; whereas 0.125 ppm Ni was phytotoxic when 62.5 ppm Na, which is nontoxic, was added to the solution. Therefore, synergistic effects of chemicals in the organic amendments may induce phytotoxicity.

Prevalence, Concentration, and Antimicrobial Resistance Profiles of Salmonella Isolated from Florida Poultry Litter

ABSTRACT

For over a decade, Salmonella contamination has increasingly led to outbreaks of foodborne illness associated with fresh produce. The use of untreated animal manures, or biological soil amendments of animal origin, to amend agricultural soils holds a risk of contamination from foodborne pathogens, such as Salmonella. This study was conducted to determine the prevalence, concentration, serotypes, and antimicrobial resistance profiles of Salmonella in poultry litter from Florida farms. Litter pH, total Kjeldahl nitrogen, total ammonia nitrogen, total phosphorus (P2O5), total potassium (K2O), moisture content, total solids, total ash, organic matter, and aerobic plate count (APC) were also measured. Litter samples (n = 54) were collected from 18 broiler farms across three seasons (spring, summer, and winter). Salmonella concentrations were enumerated using a most-probable-number (MPN) method, and antimicrobial susceptibility testing was performed. The prevalence of Salmonella in litter samples was 61.1%, with a geometric mean of 0.21 ± 20.7 MPN/g. Across all seasons, Salmonella concentrations were not influenced by the chemical, physical, or microbial properties measured. Recovered Salmonella isolates (n = 290) were grouped into serogroups O:4 (43.1%), O:7 (26.9%), O:8 (11.0%), O:1,3,10,19 (7.9%), and O:9,46 (7.2%). Serotyping Salmonella isolates (n = 47) resulted in 12 serotypes, with the most common being Typhimurium (27.7%), Kentucky (17.0%), Enteritidis (14.9%), and Mbandaka (14.9%). Antimicrobial resistance to tetracycline (29.8%), sulfisoxazole (23.4%), and streptomycin (14.9%) was observed. No isolates were resistant to more than two antimicrobial agents. This study provides valuable information for future risk assessments for the use of poultry litter as an untreated biological soil amendment of animal origin.

HIGHLIGHTS

Exposure pathways and ecological risk assessment of common veterinary antibiotics in the environment through poultry litter in Bangladesh

Veterinary antibiotics (VAs) have entered the ecosystem principally through the application of organic fertilizer. However, factors influencing the contributions made by the prescribers and users thereof with respect to VAs in poultry manure have not been investigated. The purpose of this paper, therefore, is to identify factors associated with the VA prescription and usage as well as to measure the residual concentration along with the ecological risk of common VAs in poultry litter in Bangladesh. Structured questionnaire surveys were conducted so as to provide an understanding the perspective of prescribers and farmers. Ciprofloxacin (CIP), enrofloxacin (ENR), oxytetracycline (OTC), and doxycycline (DOX) were screened through the use of thin-layer chromatography (TLC) and quantified through high-performance liquid chromatography (HPLC). Also, methods of risk quotient (RQ) were applied to assess ecotoxicity. Most VAs were prescribed without a confirmatory diagnosis. The residue of CIP was dominant with a high concentration, followed by OTC but with a low concentration. A high ecological risk was associated with the use of OTC and DOX whereas the risk associated with the use of CIP and ENR was insignificant to low. The study highlights prescriber and user factors along with the variable ecological risk of VAs in litter.

Anaerobic digestion of poultry litter - A consequential life cycle assessment

Concentrated land spreading of poultry litter has the potential to cause nutrient build-up in soils, eutrophication of water bodies, air pollution and the spread of pathogens. As a result, alternative routes for the disposal of poultry litter are being sought. A consequential life cycle assessment was conducted to examine several scenarios where biogas produced from poultry litter is used to generate heat and electricity or is upgraded to biomethane which can substitute natural gas. For all of the scenarios considered in this study, diverting poultry litter to anaerobic digestion leads to reduced environmental impacts for global warming, fine particulate matter formation and terrestrial acidification. However, the extent to which environmental impacts are reduced varies significantly across the scenarios. Displaced processes including electricity or natural gas, peat moss production and avoided land spreading of litter contribute the most to reducing environmental impacts. Consequential life cycle assessment is a suitable tool to inform decision-makers about the impact of introducing a new multifunctional technology like anaerobic digestion when considering the systems which are displaced. The results show the range of potential environmental outcomes, rather than predicting a single most-likely outcome. The results of this study indicate that anaerobic digestion is a suitable disposal route for poultry litter which may lead to reduced environmental impacts. This type of analysis is recommended when considering alternative feedstocks and valorisation pathways in the circular economy.

Fluoroquinolones and trace elements in poultry litter: estimation of environmental load based on nitrogen requirement for crops

Poultry litter soil application contributes to sustainability of agricultural systems and is in accordance with the United Nations Sustainable Development Goals (UN-SDG). Poultry litter recommended rates are based on crop nitrogen (N) needs, however, their application can be a potential source of antibiotics and trace elements overload. The aim of the study was to estimate the role of poultry litter application on soil contamination by fluoroquinolones [enrofloxacin (ENR) and ciprofloxacin (CIP)] and trace elements, based on N requirements for crops. Analytical and sampling techniques were used to estimate the loads from poultry litter application. Only CIP was found in poultry litter samples (283 ± 124 µg kg^-1) and its load was estimated to be of 9.89 ± 4.33 g ha^-1, for the poultry litter application (35 t ha^-1). The estimated loads (g ha^-1) of trace elements were: Cr 9.19 ± 3.26, Ni 12.3 ± 4.93, Pb 22.0 ± 8.26, Cu 229 ± 85.6, Mn 691 ± 259 and Zn 1,011 ± 378. These estimates were 900% higher than those recommended by the technical guidance, while N exceeded 600% the recommended application. In order to achieve UN-SDGs, local policies to disseminate knowledge and technologies are required for consolidating sustainable agricultural practices.

Nitro-treatment of composted poultry litter; effects on Salmonella, E. coli and nitrogen metabolism

Poultry litter is a potentially valuable crude protein feedstuff for ruminants but must be treated to kill pathogens before being fed. Composting kills pathogens but risks losses of nitrogen due to volatilization or leaching as ammonia. Treatment of poultry litter with ethyl nitroacetate, 3-nitro-1-propionate, ethyl 2-nitropropionate (at 27 µmol/g), decreased numbers of experimentally-inoculated Salmonella Typhimurium (>1.0 log₁₀ compared to controls, 4.2 ± 0.2 log₁₀ CFU/g) but not endogenous Escherichia coli early during simulated composting. By day 9 of simulated composting, Salmonella and E. coli were decreased to non-detectable levels regardless of treatment. Some nitro-treatments preserved uric acid and prevented ammonia accumulation, with 18% more uric acid remaining and 17-24% less ammonia accumulating in some nitro-treated litter than in untreated litter (18.1 ± 3.8 µmol/g and 3.4 ± 1.4 µmol/g, respectively). Results indicate that nitro-treatment may help preserve uric acid in composted litter while aiding Salmonella control.

A Review of Antimicrobial Resistance in Poultry Farming within Low-Resource Settings

The emergence, spread, and persistence of antimicrobial resistance (AMR) remain a pressing global health issue. Animal husbandry, in particular poultry, makes up a substantial portion of the global antimicrobial use. Despite the growing body of research evaluating the AMR within industrial farming systems, there is a gap in understanding the emergence of bacterial resistance originating from poultry within resource-limited environments. As countries continue to transition from low- to middle income countries (LMICs), there will be an increased demand for quality sources of animal protein. Further promotion of intensive poultry farming could address issues of food security, but it may also increase risks of AMR exposure to poultry, other domestic animals, wildlife, and human populations. Given that intensively raised poultry can function as animal reservoirs for AMR, surveillance is needed to evaluate the impacts on humans, other animals, and the environment. Here, we provide a comprehensive review of poultry production within low-resource settings in order to inform future small-scale poultry farming development. Future research is needed in order to understand the full extent of the epidemiology and ecology of AMR in poultry within low-resource settings.

Phenomenal Bombardment of Antibiotic in Poultry: Contemplating the Environmental Repercussions

Antibiotics have constantly been added at an unprecedented rate in order to enhance poultry meat production. Such antibiotics impose a negative impact on human health directly through meat and egg consumption. On the other hand, they also affect humans indirectly by affecting the normal key microbial processes in the agricultural environments, when used as poultry compost. For many years, farmers have been turning poultry litter into compost for agricultural use. Very few studies have addressed the fate of the unmetabolized antibiotic residues in poultry litter that could potentially affect microbial communities when used as poultry compost. We have also questioned the fate of residual antibiotic in poultry waste which may create possible negative environmental pressure on microbial communities that are involved in microbial mediated poultry litter composting processes. The incorporation of antibiotic degrading environmental isolates in poultry litter at the initial stage of composting in order to accelerate the process is addressed in this review as a future perspective.

Management of poultry manure in Poland - Current state and future perspectives

This review aimed to analyse the current state of management practices for poultry manure in Poland and present future perspectives in terms of technologies allowing closing the loops for circular economy, and thus recovery of nutrients and energy. The scope of the review focused primarily on: (1) the analysis of poultry production and generation of poultry manure with special references to quantities, properties (e.g. fertilizing properties), seasonality, etc.; (2) the overview of current practices and methods for managing poultry manure including advantages and limitations; (3) the analysis of potential and realistic threats and risk related to managing poultry manure, and also (4) the analysis of promising technologies for converting poultry manure into added value products and energy. The review addressed the following technologies: composting of poultry manure to obtain fertilizers and soil improvers, anaerobic digestion of poultry manure for energy recovery, and also pyrolysis of poultry manure into different types of biochar that can be applied in agriculture, horticulture and industry. Poultry manure is rich in macro- and micronutrients but also can contain various contaminants such as antibiotics or pesticides, and thus posing a realistic threat to soil and living organisms when applied to soil directly or after biological treatment. The main challenge in poultry manure processing is to assure sufficient closing of carbon, nitrogen and phosphorous loops and safe application to soil.

The Effect of Scale on the Performance of an Integrated Poultry Slaughterhouse Wastewater Treatment Process

The efficiency of a wastewater treatment process may be affected by several factors including the scale at which the system is operating. This study aimed at investigating the influence of scale on a poultry slaughterhouse wastewater treatment process. The process is comprised of several units including electrolysis, membrane filtration, and ultraviolet irradiation. The results of the industrial-scale wastewater treatment plant of the Izevski poultry farm slaughterhouse in Kazakhstan were compared with those of a lab-scale wastewater treatment process under the same conditions. The traditional and water quality index (WQI) approaches were used to present the results and the drinking water quality standards of Kazakhstan were used as a reference. The industrial and lab-scale plants showed high purification efficiency for most of the studied water quality parameters. The comparative analysis based on the WQI showed that the industrial-scale wastewater treatment plant outperforms the lab-scale wastewater treatment process.

Effect of soil type and temperature on survival of Salmonella enterica in poultry manure-amended soils

The effects of soil type and temperature on the survival of a cocktail of five Salmonella enterica serotypes (Enteritidis, Infantis, Montevideo, Typhimurium and Zanzibar) in manure-amended soils under controlled laboratory conditions was assessed. Containers of clay loam or sandy soil, unaltered or amended with 2% (w/w) poultry manure, were inoculated with S. enterica (~5 log₁₀ CFU per gram) and held at 5, 21 or 37°C for 6 weeks. Statistical analysis of the persistence of S. enterica identified a significant three-way interaction between soil type, manure amendment and temperature. Clay loam soils and lower temperatures tended to support S. enterica persistence over 6 weeks with only 1- and 2-log reductions respectively. In contrast, sand and higher temperatures resulted in a 4-log and either 3- to 4-log reductions respectively. Manure amendment had an overarching effect of reducing die-off of S. enterica in comparison with unamended soils. This study highlights that a large component of variation of the rate of S. enterica reduction in soils may be attributed to combinations of environmental factors, in particular, soil type and temperature. It further underscores the importance of risk management strategies and industry guidelines based on local data and that reflect the diversity of prevailing horticultural production environments. SIGNIFICANCE AND IMPACT OF THE STUDY: The persistence of Salmonella enterica in soil environments was shown to be significantly influenced by a range of individual and interacting environmental effects, including temperature, soil type and amendment addition. This indicates that current horticultural food safety management systems which employ a uniform prescribed exclusion period between application of manure and time of harvest may be unfit for purpose under certain conditions by either underestimating or overestimating pathogen die-off. These findings support exclusion periods that account for a range of environmental factors including temperature, soil type and growing region that may be more appropriate to manage microbiological risks associated with soil which has been amended with manure.

Influence of bamboo biochar on mitigating greenhouse gas emissions and nitrogen loss during poultry manure composting

The effectiveness of specific concentrations of bamboo biochar (BB) on nutrient conservation based on gaseous emissions during poultry manure composting was investigated. The results indicate that the total carbon and nitrogen losses were significantly reduced with elevated of biochar from 542.8 to 148.9% and 53.5 to 12.6% (correspondingly with an additive of 0%, 2%, 4%, 6% and 8% to 10% BB dry weight based). The primary contributor was CO₂ and NH₃ losses (542.3-148.8% and 47.8-10.81%). The enzyme activities related to carbon and nitrogen metabolism indicated a positive and significantly enhanced with high concentration biochar amended composting. Simultaneously, the alteration of total organic carbon and total Kjeldahl nitrogen as well as maturity indexes during ultimate compost also confirmed a high quality product under higher content biochar amended composting. Carbon and nitrogen were best preserved with 10%BB and produced a superior final product. The analysis of a network and heat map illustrated the correlation of gaseous and physicochemical elements as well as enzyme activities, with an intersection of 68.81%.

Prevalence and characteristics of extended-spectrum β-lactamases-producing Escherichia coli from broiler chickens at different day-age

Commensal Escherichia coli from the poultries have been considered as reservoirs of extended-spectrum β-lactamases (ESBL)-encoding genes. Between May 2018 and March 2019, a total of 340 E. coli isolates were obtained from apparently healthy broiler chickens from 20 to 40 D old, distributed in 17 small-scale commercial farms. Finally, 45 isolates (8 from 20-day-old broiler chickens, 14 from 30-day-old ones, and 23 from 40-day-old ones) were identified as ESBL producers, which were further investigated to shed light on the virulence gene profiles, phylogenetic groups, and multilocus sequence types and to detect the ESBL plasmid-mediated quinolone resistance determinant (PMQR) genes as well as the mutations in the quinolone resistance-determining regions (QRDR) of gyrA and parC. Molecular analysis showed that phylogenic group A and B1 accounted for 66.7% of the ESBL producers. The overall occurrence of virulence genes ranged from 5.1% (cva) to 86.7% (papC). Twenty (44.4%) ESBL producers were considered as biofilm producers with moderate or heavy biofilm formation. The most predominant specific CTX-M subtype was bla_CTX-M-14 (n = 19), followed by bla_CTX-M-9 (n = 17), bla_CTX-M-55 (n = 9), bla_CTX-M-15 (n = 6), bla_CTX-M-1 (n = 5), and bla_CTX-M-65 (n = 4). Additionally, PMQR genes were identified in 86.7% of ESBL producers, qnrS (n = 21) was the most dominant PMQR gene, followed by the aac(6')-Ib-cr (n = 15), qnrB (n = 12), and qnrA (n = 9), and all of them co-expressed with β-lactamase genes. All PMQR-positive isolates harbored simultaneously at least 1 mutation in the QRDR of gyrA and parC. Forty-five ESBL producers were assigned to 33 sequence types, and the most frequent sequence types (STs) was ST10 (n = 5) and followed by ST95 (n = 3). Additionally, ST302, ST88, ST410, ST187, and ST23 were represented by 2 ESBL producers, respectively, and the remaining ones exhibited diverse ST. Moreover, the prevalence of ESBL producers, the biofilm-forming ability, and the occurrence of the QRDR mutations among the E. coli isolates were characterized by gradually increased with advancing age of broiler chickens.

Evaluation of Alternative Annular Denuder Systems for the Collection of Fine Aerosol Particulate Matter

Due to the complex manner in which secondary inorganic aerosols (SIAs) form, a need exists to develop a methodology to measure PM2.5 emissions from agricultural operations to better understand the contribution of SIAs to the PM2.5 fraction. When sampling particulate matter (PM), annular denuder systems (ADS) are a United States Environmental Protection Agency (US EPA) approved system used to measure both gaseous and particulate components of aerosols. While collecting basic gases, such as ammonia, using nine denuders was feasibly demonstrated in poultry housing units but the ability of additional denuders to accurately collect the SIAs on the filters is yet to be demonstrated. An experiment was designed to assess particle deposition behaviors throughout three different ADS configurations. It was determined that the nine denuder configuration resulted in particles being impacted and retained, mainly in the U-bend junctions, prior to reaching the filters with only 87.2% of PM2.5 reaching the filter pack. The US EPA-prescribed ADS configuration had 99.4% of PM2.5 reaching the filters, indicating that there is an impact due to the U-Bend addition to the system. It was further demonstrated that having additional denuders in series with no U-Bend had no significant impact on PM2.5 deposition on the filters with 98.9% of PM2.5 being collected.

Suitability of litter amendments for the Australian chicken meat industry

The Australian chicken meat indutstry is rapidly expanding due to the increasing consumption of chicken meat. As a result, the industry has growing issues of sourcing new bedding materials and disposing of spent litter, which can be attributed, in part, to a lack of widespread litter re-use for rearing chickens. According to insights and perspectives recently gathered from industry stakeholders, it is believed that re-using litter will become more common in the future, so as to reduce production costs and ease pressures on both the supply of new bedding materials and disposal of spent litter. However, there are potential risks that need to be addressed if litter re-use increases, particularly with regard to the production and mitigation of ammonia, which can negatively affect chicken health if not managed correctly. The present review discusses the potential benefits reported for different types of litter amendments, which have the primary goal of reducing ammonia volatilisation, but may also contribute to improvements in bird performance, welfare, pathogen loads, fertiliser value of spent litter, and reduced costs associated with purchasing new bedding materials. Acidifiers have been shown to be the most effective of all amendment types, with sodium bisulfate or alum being among the most commonly tested products mentioned in research literature. Litter amendments are currently rarely used in Australia, but it is hoped that the information provided in the present review, based mostly on overseas usage and research, will help inform future decision-making on the use of these products in Australian poultry production systems.

Factors Impacting the Prevalence of Foodborne Pathogens in Agricultural Water Sources in the Southeastern United States

Surface water poses a great risk to fruit and vegetable crops when contaminated by foodborne pathogens. Several factors impact the microbial quality of surface waters and increase the risk of produce contamination. Therefore, evaluating the factors associated with the prevalence of pathogenic microorganisms in agricultural water sources is critical to determine and establish preventive actions that may minimize the incidence of foodborne outbreaks associated with contaminated production water. In the Southeastern U.S. environmental factors such as rainfall, temperature, and seasonal variations have been associated with the prevalence of pathogens or microbial indicators of fecal contamination in water. Also, the geographical location of the irrigation sources as well as surrounding activities and land use play an important role on the survival and prevalence of pathogenic bacteria. Therefore, these factors may be determinants useful in the evaluation of production water quality and may help to preemptively identify scenarios or hazards associated with the incidence of foodborne pathogenic microorganisms.

Improving Biomethanation of Chicken Manure by Co-Digestion with Ethanol Plant Effluent

As the global production of chicken manure has steadily increased, its proper management has become a challenging issue. This study examined process effluent from a bioethanol plant as a co-substrate for efficient anaerobic digestion of chicken manure. An anaerobic continuous reactor was operated in mono- and co-digestion modes by adding increasing amounts of the ethanol plant effluent (0%, 10%, and 20% (v/v) of chicken manure). Methanogenic performance improved significantly in terms of both methane production rate and yield (by up to 66% and 36%, respectively), with an increase in organic loading rate over the experimental phases. Correspondingly, the specific methanogenic activity was significantly higher in the co-digestion sludge than in the mono-digestion sludge. The reactor did not suffer any apparent process imbalance, ammonia inhibition, or nutrient limitation throughout the experiment, with the removal of volatile solids being stably maintained (56.3-58.9%). The amount of ethanol plant effluent appears to directly affect the rate of acidification, and its addition at ≥20% (v/v) to chicken manure needs to be avoided to maintain a stable pH. The overall results suggest that anerobic co-digestion with ethanol plant effluent may provide a practical means for the stable treatment and valorization of chicken manure.

Characterisation of ashes from waste biomass power plants and phosphorus recovery

Biowastes, such as meat and bone meal (MBM), and poultry litter (PL), are used as energy sources for industrial combustion in the UK. However, the biomass ashes remaining after combustion, which contain nutrients such as phosphorus, are landfilled rather than utilised. To promote their utilisation, biomass ashes from industries were characterised in terms of their elemental and mineral compositions, phosphorus extractability, and pH-dependent leachability. These ashes were highly alkaline (pH as high as 13), and rich in calcium and phosphorus. The P bio-availabilities in the ash evaluated by Olsen's extraction were low. Hydroxyapatite and potassium sodium calcium phosphate were identified by X-ray powder diffraction (XRD) as the major phases in the MBM and PL ashes, respectively. The leaching of P, Ca, and many other elements was pH dependent, with considerable increase in leaching below about pH 6. P recovery by acid dissolution (e.g., with H₂SO₄) seems feasible and promising; the optimized acid consumption for ~90% P recovery could be as low as 3.2-5.3 mol H⁺/mol P.

Best management practices from agricultural economics: Mitigating air, soil and water pollution

Often the several stakeholders involved in the agricultural sector place a greater emphasis on the negative externalities from farming production rather than on the solutions and approaches to mitigate, namely impacts from pollution. The scientific literature, in certain circumstances, follows this tendency leaving a vast chasm of enormous potential left to be explored. It is important to contribute towards the reduction of this gap, highlighting the best management practices implemented across the agricultural sector around the world, specifically to make them more visible and give incentive to the several agents in adopting and spreading their use. In this way, the main objective is to stress the best management practices presented by the global scientific literature from the farming sector. To achieve this objective methodology based on bibliometric analysis-factor-analysis-literature survey approach was considered, applied to 150 documents obtained from the Web of Science (core collection) related with the following topics: best management practice; agricultural economics; air, soil and water pollution. As main insights, it is worth referring the best management practices to deal with problems from agricultural production, such as, for example, the use of agricultural residues as feedstock for renewable energies. With regard to sustainable development in the agricultural sector, concepts such as "sustainable remediation" have their place. On the other hand, the agricultural and environmental policies and the agricultural costs associated with the several farming practices also play a determinant role here. Finally, only fraction of the scientific documents analysed (16 papers) belong to the group of studies related to policies, showing that there are potential subjects to be addressed here in future studies related with these topics. The same happens for cost-benefit analyses (24 documents).

How Safe is Chicken Litter for Land Application as an Organic Fertilizer? A Review

Chicken litter application on land as an organic fertilizer is the cheapest and most environmentally safe method of disposing of the volume generated from the rapidly expanding poultry industry worldwide. However, little is known about the safety of chicken litter for land application and general release into the environment. Bridging this knowledge gap is crucial for maximizing the benefits of chicken litter as an organic fertilizer and mitigating negative impacts on human and environmental health. The key safety concerns of chicken litter are its contamination with pathogens, including bacteria, fungi, helminthes, parasitic protozoa, and viruses; antibiotics and antibiotic-resistant genes; growth hormones such as egg and meat boosters; heavy metals; and pesticides. Despite the paucity of literature about chicken litter safety for land application, the existing information was scattered and disjointed in various sources, thus making them not easily accessible and difficult to interpret. We consolidated scattered pieces of information about known contaminants found in chicken litter that are of potential risk to human, animal, and environmental health and how they are spread. This review tested the hypothesis that in its current form, chicken litter does not meet the minimum standards for application as organic fertilizer. The review entails a meta-analysis of technical reports, conference proceedings, peer-reviewed journal articles, and internet texts. Our findings indicate that direct land application of chicken litter could be harming animal, human, and environmental health. For example, counts of pathogenic strains of Eschericiacoli (10⁵–10¹⁰ CFU g⁻¹) and Coliform bacteria (10⁶–10⁸ CFU g⁻¹) exceeded the maximum permissible limits (MPLs) for land application. In Australia, 100% of broiler litter tested was contaminated with Actinobacillus and re-used broiler litter was more contaminated with Salmonella than non-re-used broiler litter. Similarly, in the US, all (100%) broiler litter was contaminated with Eschericiacoli containing genes resistant to over seven antibiotics, particularly amoxicillin, ceftiofur, tetracycline, and sulfonamide. Chicken litter is also contaminated with a vast array of antibiotics and heavy metals. There are no standards set specifically for chicken litter for most of its known contaminants. Even where standards exist for related products such as compost, there is wide variation across countries and bodies mandated to set standards for safe disposal of organic wastes. More rigorous studies are needed to ascertain the level of contamination in chicken litter from both broilers and layers, especially in developing countries where there is hardly any data; set standards for all the contaminants; and standardize these standards across all agencies, for safe disposal of chicken litter on land.

Nitrogen Mineralization in a Sandy Soil Amended with Treated Low-Phosphorus Broiler Litter

Low-phosphorus (P) litter, a manure treatment byproduct, can be used as an organic soil amendment and nitrogen (N) source but its effect on N mineralization is unknown. A laboratory incubation study was conducted to compare the effect of adding untreated (fine or pelletized) broiler litter (FUL or PUL) versus extracted, low-P treated (fine or pelletized) broiler litter (FLP or PLP) on N dynamics in a sandy soil. All four litter materials were surface applied at 157 kg N ha−1. The soil accumulation of ammonium (NH4+) and nitrate (NO3−) were used to estimate available mineralized N. The evolution of carbon dioxide (CO2), ammonia (NH3), and nitrous oxide (N2O) was used to evaluate gaseous losses during soil incubation. Untreated litter materials provided high levels of mineralized N, 71% of the total N applied for FUL and 64% for PUL, while NH3 losses were 24% to 35% and N2O losses were 3.3% to 7.4% of the total applied N, respectively. Soil application of low-P treated litter provided lower levels of mineralized N, 42% for FLP and 29% for PLP of the total applied N with NH3 losses of 5.7% for FLP for and 4.1% for PLP, and very low N2O losses (0.5%). Differences in mineralized N between untreated and treated broiler litter materials were attributed to contrasting C:N ratios and acidity of the low-P litter byproducts. Soil application of treated low-P litter appears as an option for slow mineral N release and abatement of NH3 and N2O soil losses.

Fertilizer Efficacy of Poultry Litter Ash Blended with Lime or Gypsum as Fillers

Ash from power plants that incinerate poultry litter has fertilizer value, but research is lacking on optimal land application methodologies. Experiments were conducted to evaluate calcitic lime and flue gas desulfurization gypsum (FGDG) as potential fillers for poultry litter ash land applications. The ash had phosphorus (P) and potassium (K) contents of 68 and 59 g kg−1, respectively. Soil extractable P and K were measured in an incubation pot study, comparing calcitic lime to FGDG at filler/ash ratios of 1:3, 1:2, 1:1, 2:1, and 3:1. After one month, soils were sampled and annual ryegrass (Lolium multiflorum Lam.) seeds were planted to investigate how plant growth and uptake of P and K were influenced by the fillers. Application of ash alone or with fillers increased soil extractable P and K levels above unamended controls by 100% and 70%, respectively. Filler materials did not affect biomass or P and K concentration of the ryegrass. A field study with a commercial spinner disc fertilizer applicator was conducted to compare application uniformity of ash alone and filler/ash blends. Overall, test data suggested that uniform distribution of ash alone or with fillers is feasible in field applications using a commercial fertilizer spreader.

Fast Pyrolysis of Poultry Litter in a Bubbling Fluidised Bed Reactor: Energy and Nutrient Recovery

Livestock production is among the most rapidly growing sectors of the agricultural economy driven primarily by growing demand for animal protein, but also posing significant waste disposal issues and environmental impacts. Moreover, opportunities exist for utilising animal waste at the farm level for heat and power generation (thermal conversion) which can contribute to economic sustainability and also provide a bio-fertiliser for soil amendment. The present study is focused on energy and nutrient recovery from poultry litter using a thermochemical conversion technology (fast pyrolysis). The formation of products (gases, biochar and bio-oil) during the fast pyrolysis of poultry litter was experimentally investigated in a laboratory-scale bubbling fluidised bed reactor. Pyrolytic gases accounted for 15–22 wt.% of the product. The carbon content in biochar increased from 47 to 48.5 wt.% with an increase in the pyrolysis temperature. Phosphorous and potassium recovery in the biochar were over 75%, suggesting that it could be used as an organic soil amendment. The high ash content in poultry litter (14.3 wt.%) resulted in low bio-oil and high biochar yield. The bio-oil yield was over 27 wt.% with a higher heating value of 32.17 MJ/kg (dry basis). The total acid number of the bio-oil decreased from 46.30 to 38.50 with an increase in temperature. The nitrogen content in the bio-oil produced from the poultry litter (>7 wt.%) was significantly higher compared to bio-oil produced from the wood (0.1 wt.%).

Enhancing naked oat (Avena nuda L.) productivity with minimal indirect nitrogen loss and maximum nitrogen use efficiency through integrated use of different nitrogen sources

Oat (Avena nuda L.) is a nutritious grain crop, rich in dietary fibers and phytochemicals. Application of efficient nitrogen (N) sources and dose is very important to obtain higher crop productivity and to achieve environmental sustainability. The exploitation of natural beneficial microbes and organic nitrogen in combination with chemical nitrogen would be effective to boost soil N for plant uptake. Hence, a field experiment was conducted during 2016 and 2017 with the aim to ameliorate the use of chemical N (CN) with organic nitrogen (ON) and microbial fertilizer (MBF) without compromising the productivity of oat. T1 = control, T2 = 100% CN, T3 = 100% CN+MBF, T4 = 75% CN+ 25% ON+MBF, T5 = 50% CN+ 50% ON+MBF, T6 = 100% ON+MBF, T7 = 100% ON were the treatments. 50% CN + 50% ON + MBF treatment proved to be an efficient combination regarding enhanced biomass and grain yield, nitrogen uptake and NUE as compared to rest of the treatments in both years. During the critical stages of the crop, when most of the applied CN was leached from the top 20 cm soil depth, a substantial N came from the PM mineralization through enhanced microbial activity by the addition of MBF. Lastly, the application of ON supplemented with MBF improved the rhizosphere soil properties, i.e. mineral N concentration, total N (TN), soil organic carbon (SOC), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), soil respiration rate and enzymatic activity. A balanced and source conscious application of CN, ON and MBF reduced N losses and added a substantial amount of N into the soil N pool. We concluded that organic N combined with chemical N and MBF proved to be effective in improving soil properties ensuring less N loss and increasing oat production in the semi-arid region.

Pinto peanut cover crop nitrogen contributions and potential to mitigate nitrous oxide emissions in subtropical coffee plantations

Many coffee (Coffea arabica L) production systems are characterised by high use of nitrogen (N) fertilisers, which can result in N leaching and emissions of nitrous oxide (N₂O). We investigated the potential for legume cover crops grown inter-row to provide N for coffee trees and lower seasonal N₂O emissions compared to poultry litter amendment at two subtropical field sites over 12 months, with unfertilised traditional grass groundcover used as a control treatment. Groundcovers (legume and grass treatments) were slashed from the inter-row into the tree line every 2-6 weeks as per normal farming operations. The prostrate ground cover legume Pinto peanut (Arachis pintoi) produced 4-5 t ha^-1 biomass at both sites over the 12 month period, and fixed 146 kg N ha^-1 year^-1 at one site as estimated using the ¹⁵N natural abundance method. Background emissions from soil were lower at site 1 (0.38 kg N₂O-N ha^-1 year^-1) than site 2 (2.26 kg N₂O-N ha^-1 year^-1) reflecting differences in soil N and C levels at the sites. The use of Pinto peanut residues as an N amendment didn't result in any N₂O flux events beyond those observed in the traditional groundcover control treatment across the season at either site, while the application of poultry litter to match farmer practice at these sites led to a major emission event. Ultimately, the Pinto peanut cover crop treatment led to a lower emission factor than for poultry litter at both sites, and resulted in significantly lower cumulative seasonal emissions for the legume cover crop (0.34 kg N₂O-N ha^-1 season^-1) than poultry litter amendment (0.68 kg N₂O-N ha^-1 season^-1) at site 1 despite similar inputs of N into the system. These findings suggest cover crop legumes could be integrated into coffee plantations to offset a portion of external N inputs, while lowering N₂O emissions.

Effect of pH-lowering litter amendment on animal-based welfare indicators and litter quality in a European commercial broiler husbandry

Several studies have shown that litter moisture is a major reason for foot pad lesions (FPD) and promotes microbial growth of nitrifying bacteria. The aim of the current study was to determine the possible effects of a sodium bisulfate complex (SBS) as a litter additive on FPD, hock burn (HB), and litter parameters. Two application rates of SBS were examined in 2 experiments on a commercial farm. Two groups of about 30,000 broiler chicks each were introduced on spelt granulate spread at 700 g/m² and kept for 36 d. In the first experiment (TRT1), 250 g/m² SBS was spread on top of litter 20 h before chick placement; in the second experiment (TRT2), SBS was reduced to 150 g/m². Each experiment consisted of 1 treatment group (SBS) and a control group without treatment (CON). Both experiments were repeated once. Litter parameters (pH, percentage of dry matter), foot pad, hock condition and body weight of randomly sampled birds (n = 60 per group) were recorded weekly. Mortality rate was higher in SBS groups compared to CON groups (TRT1 2.79 vs. CON 2.03%, TRT2 2.88 vs. CON 2.27%). SBS had no effect on body weight averaged over the whole production period (P > 0.05). Incidence of FPD was significantly reduced in both groups treated with SBS compared to CON (P < 0.05), with group TRT1 showing the best results. Incidence of HB was not affected by SBS (P > 0.05) but by dry matter content (P < 0.05). At the beginning, SBS reduced litter pH to 1.7 and 2.0 in TRT1 and TRT2, respectively, compared to 6.5 and 6.7 in CON. Litter pH in TRT groups increased over time and approached pH of control groups by day 15. Results of the current study indicate that SBS treatment may be beneficial regarding foot pad health in broilers. However, further studies are needed to investigate alternative SBS application rates, and to verify the results.

Fluoroquinolones in agricultural soils: Multi-temporal variation and risks in Rio de Janeiro upland region

Our main goal was to investigate the potential accumulation of fluoroquinolones (FQs) in agricultural soils over extended periods of land use, predicting leaching and estimating risk quotients for soil microorganisms. Short to long-term of poultry litter fertilization (<1-30 years) were evaluated for enrofloxacin (ENR) and ciprofloxacin (CIP) input, in addition to the emergence of plasmid-mediated quinolone resistance (PMQR) genes. High FQs concentration (range 0.56-100 mg kg^-1) were measured in poultry litter samples. In soils, FQs occurrence and risks have changed over the years. An accumulation trend was observed between short and medium-term fertilized soils (ST and MT soils), reaching a range of 330-6138 μg kg^-1 ENR and 170-960 μg kg^-1 CIP in MT soil, followed by decreased concentrations in long-term fertilized soils (LT soils). The environmental risk assessment showed a high ENR risk quotient (RQ ≥ 1) in ST and MT soils ranging (7-226) and high CIP risk (9-53) in LT soils. The detection of qnrS genes in the area with the lowest FQs concentration emphasizes the importance of a broader approach to environmental assessment, in which not only target compounds are considered. FQs soil-water migration model pointed out a high leaching risk in ST soil. To reduce risks, management measures to decrease antibiotic environmental load should be taken before poultry litter application. In addition, the high weathering of tropical soils contributing to possible fate of antibiotics to water resources through drainage basins should be considered.

Evaluation of phytotoxicity of three organic amendments to collard greens using the seed germination bioassay

Small-scale vegetable and fruit crop producers in the USA use locally available commercial organic fertilizers and soil amendments recycled from municipal and agricultural wastes. Organic soil amendments provide crops with their nutrient needs and maintain soil health by modifying its physical, chemical, and biological properties. However, organic soil amendments might add unwanted elements such as toxic heavy metals or salts, which might inhibit crop growth and reduce yield. Therefore, the objective of this study was to evaluate phytotoxicity of three commercial organic amendments, chicken manure, milorganite, and dairy manure, to collard greens using the seed germination bioassay and chemical analysis of the organic amendments. The seed germination bioassay was conducted by incubating collard greens seeds to germinate in 1:10 (w/v) organic amendment aqueous extracts. Results of this work identified phytotoxic effects of chicken manure and milorganite, but not dairy manure, to collard greens. Potentially phytotoxic chemicals such as copper, zinc, nickel, and salts were also higher in chicken manure and milorganite compared to dairy manure. In particular, nickel in chicken manure and milorganite aqueous extracts was 28-fold and 21-fold, respectively, higher than previously reported toxic levels to wheat seedlings. The results demonstrate the need for more research on phytotoxicity of commercial organic soil amendments to ensure their safe use in vegetable and fruit crop production systems.

Multi-temporal accumulation and risk assessment of available heavy metals in poultry litter fertilized soils from Rio de Janeiro upland region

Poultry litter is widely used as fertilizer in soils and can be a relevant source of heavy metals for agricultural environments. In this study, poultry litter fertilization of long-term (< 1-30 years) was evaluated in tropical soils. Our main goal was to investigate the occurrence of temporal variation in the available fraction of heavy metals (Cu, Cr, Zn, Pb, Cd, and Mn) in soils, in addition to their environmental loads through new indexes for risk assessment. The highest mean concentrations in poultry litter were the following: 525 mg kg^-1 for Mn, 146 mg kg^-1 for Zn, and 94.4 mg kg^-1 for Cu. For soils, concentrations were higher for the same heavy metals: Mn (906 mg kg^-1), Zn (111 mg kg^-1), and Cu (26.3 mg kg^-1). Significant accumulation (p < 0.05) in fertilized soils was observed for Cu, Cr, and Zn. The high estimates of poultry litter input based on geological background (LI_GB) for Cu, Cr, and Zn coincided with the accumulation observed in soils, confirming the effectiveness of the index. The risk of biogeochemical transfer based on fertilized soils (LI_FS) decreased for Cu, Cr, and Zn between 10 and 30 years of soil fertilization. For Mn, a very high LI_FS was estimated in all long-term fertilized soils. The proposed indices, based on heavy metal concentration, can be used in risk assessments to guide future studies that analyze other environmental matrices possibly impacted by manure and poultry litter fertilization.

Anaerobic co-digestion of poultry litter and wheat straw affected by solids composition, free ammonia and carbon/nitrogen ratio

In this study, the effects of three total solids levels (2%, 5% and 10% TS) of the mixtures of poultry litter and wheat straw at different percent volatile solids from wheat straw (0%, 25% and 50% VSWS), free ammonia nitrogen (FAN) and C/N ratio on co-digesting poultry litter with wheat straw were studied in batch experiments operated at 37 °C. The results showed that adjusting the substrate C/N ratio alone could not always result in high methane yields and biogas volumes. The maximum CH₄ yield of 201 mL g^-1 initial VS was observed in the 5% TS category with VSWS being 50%. The highest specific biogas volume produced (318 mL g^-1 initial VS) was also obtained in the same solid category. A polynomial regression between FAN and the methanogenic activity was obtained with the correlation coefficient being 0.9472. A FAN inhibitory threshold concentration of 253.9 mg L^-1 was found, and a total loss of methane production occurred when the FAN concentration reached 1000 mg L^-1. An optimal TS content for anaerobic digestion of poultry litter with wheat straw was around 4.15% to achieve the best biogas yield. Similarly, for digesting poultry litter without addition of wheat straw, the TS content should be kept at around 6.8%.

Amending Poultry Broiler Litter to Prevent the Development of Stable Fly, Stomoxys calcitrans (Diptera: Muscidae) and Other Nuisance Flies

Spent poultry litter use as a fertilizer in horticulture supports stable fly Stomoxys calcitrans (L.) (Diptera: Muscidae) development. Stable fly continues to have an economic impact on livestock production and rural lifestyle in south-western Australia. The use of raw poultry manure is banned in 12 Shires surrounding Perth. The loss of market options for West Australian broiler growers has caused economic hardship. Hence, this study examined a range of chemical and biological amendments to spent poultry broiler litter in preventing stable fly and nuisance fly development. These included alkalizers (i.e., lime sand, quicklime, soda ash, and shell grit), acidifiers (aluminum sulfate, sodium bisulfate), gypsum, zeolite, spongolite, calcium cyanamide, and two fungal agents. The treated litters were placed under irrigation in horticulture with amendments added prior to them being exposed in the field as replicate 1-liter pads. In total, 19,559 stable flies developed from the spent litters exposed over five field experiments (88.7% of all flies recovered). House flies (Musca domestica L. (Diptera: Muscidae); 2,067 or 9.4%), false stable flies (Muscina stabulans Fallén (Diptera: Muscidae); 414 or 1.9%), and two sarcophagids (flesh fly) also developed from the litter. Borax completely prevented any fly development from the litter. Calcium cyanamide (1-2.5% v/v) and sodium bisulfate (10%) reduced stable fly numbers by as much as 99-100% when added to litter. Alkalizers, zeolite, spongolite, and entomopathogenic fungi had no significant impact on stable fly development. The addition of either calcium cyanamide or sodium bisulfate to raw litter can boost the fertilizer value of the litter while preventing stable fly development.

Long-term influence of trace element deficiency on anaerobic mono-digestion of chicken manure

Recent findings showed that some trace elements essential for anaerobic digestion might be deficient in chicken (laying hens) manure. In this study, the long-term influence of trace element deficiency on anaerobic mono-digestion of chicken manure was investigated. Three bench-scale anaerobic reactors were operated with or without trace element supplementation. As trace element, only Se or a mix containing Co, Mo, Ni, Se, and W was added to the reactors. The results revealed that in anaerobic digestion of chicken manure at total ammonium nitrogen concentrations over 6000 mg L^-1, Se supplementation was critical but not sufficient alone for long-term stable CH₄ production. Addition of a mix consisting of Co, Mo, Ni, Se and W resulted in a more stable digestion performance. Daily trace element mix supplementation promoted the hydrogenotrophic Methanoculleus bourgensis, which is an ammonia tolerant methanogen. The decrease in the relative abundance of Methanoculleus detected after termination of trace element addition and resulted in accumulation of acetate and propionate that followed by a significant decrease in CH₄ production.