Odour emissions from poultry litter - A review litter properties, odour formation and odorant emissions from porous materials

Lignite reduces carbon and nitrogen loss from litter in commercial broiler housing

The loss of carbon and nitrogen from broiler litter limits nutrient recycling and is damaging to the environment. This study investigated lignite, a low-rank brown coal, as an amendment to reduce the loss of carbon and nitrogen from broiler litter over 3 consecutive grow-out cycles, November 2021 to May 2022, at a commercially operated farm in Victoria, Australia. Lignite-treated litter contained significantly more carbon and nitrogen, with an increase of 70.1 g/bird and 12.6 g/bird for carbon and nitrogen, respectively. Lignite also reduced aerobic microbial respiration, with a 46.0% reduction in CO2 flux recorded in week 7 of the study, resulting in reduced mass loss. It is expected that this is a key mechanism responsible for nutrient retention in litter following treatment with lignite. Furthermore, lignite treatment lowered litter moisture content by 7, 6 and 3 percentage points for grow-out 1, 2 and 3, respectively. These findings present lignite as a beneficial litter amendment for increasing the nutrient value of waste and reducing carbon dioxide emissions. The study highlights the potential of lignite to reduce the environmental impact of poultry production and presents an alternative use for lignite as an existing resource.

Lignite reduces odour from broiler farms without reducing production performance

An unavoidable consequence of chicken meat production is the generation of substantial quantities of spent litter. This poses several environmental and social challenges, as broiler farms become hotspots for odour emissions. The main source of odour from broiler litter is the microbial decomposition of organic material. Thus, lignite's previously shown capacity to reduce microbial activity in broiler litter was expected to reduce odour emissions from broiler housing. The effect of lignite on odour emission rate (OER) (ou/s) was investigated using dynamic olfactometry over two consecutive summer broiler grow-out cycles in Victoria, Australia, with lignite applied at 3.5 kg/m2. The air quality dispersion model, AERMOD, was used to investigate how lignite's effect on OER influenced the predicted odour dispersion distances and concentrations in the context of various Australian regulatory requirements. Additionally, the effect of lignite on bird production performance was also determined. This study showed that lignite reduced the OER from commercial broiler housing by an average of 56% over both grow-outs. This effect was observed for the duration of the trial. The observed reduction in OER reduced the required separation distances by 44-53% according to the state odour criteria for Victoria, New South Wales, Queensland and South Australia. There were no observed differences in feed conversion ratio, bird live weight or mortality throughout either grow-out. This study demonstrated the capacity of lignite to reduce odour emissions from commercial broiler housing without reducing bird production performance.

Effects of dietary selenized glucose on intestinal microbiota and tryptophan metabolism in rats: Assessing skatole reduction potential

3-Methylindole (Skatole), a degradation product of tryptophan produced by intestinal microbial activity, significantly contributes to odor nuisance. Its adverse effects on animal welfare, human health, and environmental pollution have been noted. However, it is still unclear whether the intestinal microbiota mediates the impact of selenium (Se) on skatole production and what the underlying mechanisms remain elusive. A selenized glucose (SeGlu) derivative is a novel organic selenium compound. In this study, a diverse range of dietary SeGlu-treated levels, including SeGlu-deficient (CK), SeGlu-adequate (0.15 mg Se per L), and SeGlu-supranutritional (0.4 mg Se per L) conditions, were used to investigate the complex interaction of SeGlu on intestinal microbiome and serum metabolome changes in male Sprague-Dawley (SD) rats. The study showed that SeGlu supplementation enhanced the antioxidant ability in rats, significantly manifested in the increases of the activity of catalase (CAT) and glutathione peroxidase (GSH-Px), while no change in the level of malonaldehyde (MDA). Metagenomic sequencing analysis verified that the SeGlu treatment group significantly increased the abundance of beneficial microorganisms such as Clostridium, Ruminococcus, Faecalibacterium, Lactobacillus, and Alloprevotella while reducing the abundance of opportunistic pathogens such as Bacteroides and Alistipes significantly. Further metabolomic analysis revealed phenylalanine, tyrosine, and tryptophan biosynthesis changes in the SeGlu treatment group. Notably, the biosynthesis of indole, a critical pathway, was affected by SeGlu treatment, with several crucial enzymes implicated. Correlation analysis demonstrated strong associations between specific bacterial species - Treponema, Bacteroides, and Ruminococcus, and changes in indole and derivative concentrations. Moreover, the efficacy of SeGlu-treated fecal microbiota was confirmed through fecal microbiota transplantation, leading to a decrease in the concentration of skatole in rats. Collectively, the analysis of microbiota and metabolome response to diverse SeGlu levels suggests that SeGlu is a promising dietary additive in modulating intestinal microbiota and reducing odor nuisance in the livestock and poultry industry.

Effectiveness and diurnal variations of vegetative environmental buffers (VEBs) for mitigating NH3 and PM emissions from poultry houses

Air pollutants from poultry production, such as ammonia (NH3) and particulate matter (PM), have raised concerns due to their potential negative impacts on human health and the environment. Vegetative environmental buffers (VEBs), consisting of trees and/or grasses planted around poultry houses, have been investigated as a mitigation strategy for these emissions. Although previous research demonstrated that VEBs can reduce NH3 and PM emissions, these studies used a limited number of samplers and did not examine concentration profiles. Moreover, the differences between daytime and nighttime emissions have not been investigated. In this study, we characterized emission profiles from a commercial poultry house using an array with multiple sampling heights and explored the differences between daytime and nighttime NH3 and PM profiles. We conducted three sampling campaigns, each with ten sampling events (five daytime and five nighttime), at a VEB-equipped poultry production facility. NH3 and PM samples were collected downwind from the ventilation tunnel fans before, within, and after the VEB. Results showed that ground-level concentrations beyond the VEB decreased to 8.0% ± 2.7% for NH3, 13% ± 4% for TSP, 13% ± 4% for PM10, and 2.4% ± 2.8% for PM2.5 of the original concentrations from the exhaust tunnel fan, with greater reduction efficiency during daytime than nighttime. Furthermore, pollutant concentrations were positively intercorrelated. These findings will be valuable for developing more effective pollutant remediation strategies in poultry house emissions.

Microbiome-metabolomics analysis reveals abatement effects of itaconic acid on odorous compound production in Arbor Acre broilers

BACKGROUND

Public complaints concerning odor emissions from intensive livestock and poultry farms continue to grow, as nauseous odorous compounds have adverse impacts on the environment and human health. Itaconic acid is a metabolite from the citric acid cycle of the host and shows volatile odor-reducing effects during animal production operations. However, the specific role of itaconic acid in decreasing intestinal odorous compound production remains unclear. A total of 360 one-day-old chicks were randomly divided into 6 treatment groups: control group (basal diet) and itaconic acid groups (basal diet + 2, 4, 6, 8 and 10 g/kg itaconic acid). The feeding experiment lasted for 42 d.

RESULTS

Dietary itaconic acid supplementation linearly and quadratically decreased (P < 0.05) the cecal concentrations of indole and skatole but did not affect (P > 0.05) those of lactic, acetic, propionic and butyric acids. The cecal microbial shift was significant in response to 6 g/kg itaconic acid supplementation, in that the abundances of Firmicutes, Ruminococcus and Clostridium were increased (P < 0.05), while those of Bacteroidetes, Escherichia-Shigella and Bacteroides were decreased (P < 0.05), indicative of increased microbial richness and diversity. Furthermore, a total of 35 significantly (P < 0.05) modified metabolites were obtained by metabolomic analysis. Itaconic acid decreased (P < 0.05) the levels of nicotinic acid, nicotinamide, glucose-6-phosphate, fumatic acid and malic acid and increased (P < 0.05) 5-methoxytroptomine, dodecanoic acid and stearic acid, which are connected with the glycolytic pathway, citrate acid cycle and tryptophan metabolism. Correlation analysis indicated significant correlations between the altered cecal microbiota and metabolites; Firmicutes, Ruminococcus and Clostridium were shown to be negatively correlated with indole and skatole production, while Bacteroidetes, Escherichia-Shigella and Bacteroides were positively correlated with indole and skatole production.

CONCLUSIONS

Itaconic acid decreased cecal indole and skatole levels and altered the microbiome and metabolome in favor of odorous compound reduction. These findings provide new insight into the role of itaconic acid and expand its application potential in broilers.

Intensive poultry farming: A review of the impact on the environment and human health

Poultry farming is one of the most efficient animal husbandry methods and it provides nutritional security to a significant number of the world population. Using modern intensive farming techniques, global production has reached 133.4 mil. t in 2020, with a steady growth each year. Such intensive growth methods however lead to a significant environmental footprint. Waste materials such as poultry litter and manure can pose a serious threat to environmental and human health, and need to be managed properly. Poultry production and waste by-products are linked to NH₃, N₂O and CH₄ emissions, and have an impact on global greenhouse gas emissions, as well as animal and human health. Litter and manure can contain pesticide residues, microorganisms, pathogens, pharmaceuticals (antibiotics), hormones, metals, macronutrients (at improper ratios) and other pollutants which can lead to air, soil and water contamination as well as formation of antimicrobial/multidrug resistant strains of pathogens. Dust emitted from intensive poultry production operations contains feather and skin fragments, faeces, feed particles, microorganisms and other pollutants, which can adversely impact poultry health as well as the health of farm workers and nearby inhabitants. Fastidious odours are another problem that can have an adverse impact on health and quality of life of workers and surrounding population. This study discusses the current knowledge on the impact of intensive poultry farming on environmental and human health, as well as taking a look at solutions for a sustainable future.

Prediction of Ammonia Concentration in a Pig House Based on Machine Learning Models and Environmental Parameters

Accurately predicting the air quality in a piggery and taking control measures in advance are important issues for pig farm production and local environmental management. In this experiment, the NH₃ concentration in a semi-automatic piggery was studied. First, the random forest algorithm (RF) and Pearson correlation analysis were combined to analyze the environmental parameters, and nine input schemes for the model feature parameters were identified. Three kinds of deep learning and three kinds of conventional machine learning algorithms were applied to the prediction of NH₃ in the piggery. Through comparative experiments, appropriate environmental parameters (CO₂, H₂O, P, and outdoor temperature) and superior algorithms (LSTM and RNN) were selected. On this basis, the PSO algorithm was used to optimize the hyperparameters of the algorithms, and their prediction performance was also evaluated. The results showed that the R² values of PSO-LSTM and PSO-RNN were 0.9487 and 0.9458, respectively. These models had good accuracy when predicting NH₃ concentration in the piggery 0.5 h, 1 h, 1.5 h, and 2 h in advance. This study can provide a reference for the prediction of air concentrations in pig house environments.

Characteristics of Gases Emitted from Chicken Manure Wastewater and Potential Effects on Human Health

Hazardous and odorous gas emissions from chicken manure wastewater are a public preoccupation. Odor composition measurements are crucial steps to provide appropriate air pollution control measures and design strategies to minimize the human health impact. In this study, chicken manure wastewater samples were extensively analyzed in a closed system by a portable handheld gas detector to characterize the odor and chemical compositions. A portable detector was calibrated prior to sampling. The total number of 153 chemical compounds found in the chicken manure wastewater samples had various olfactory characteristics, including strong, pleasant, and odorless smells. Depending on the route of exposure, most of these chemical compounds could cause human health effects, such as irritation, burns, and severe symptoms including carcinogenic.

First report of multidrug-resistant Salmonella Infantis in broiler litter in Tolima, Colombia

Background and Aim:

Salmonella has been identified as one of the most widely distributed zoonotic pathogens in broiler litter. Multidrug-resistant strains have been isolated from salmonellosis outbreaks, compromising the success of their treatment. This study aimed to isolate and identify Salmonella spp. serovars in healthy broiler litter in Tolima (Colombia), determine their resistance to different antimicrobials, and detect genes associated with b-lactam resistance that could be useful to control Salmonella spp. in poultry.

Materials and Methods:

In total, 45 broiler litter samples were collected. Salmonella spp. was isolated and identified using selective and differential culture media and biochemical tests. Molecular confirmation of the pathogen was performed with the invA gene and serotyping by Kauffman–White scheme. Antimicrobial susceptibility to 15 antibiotics was determined by Kirby–Bauer method. In cefotaxime-resistant strains, blaCTX-M-F, blaCTX-M-1, blaCMY, and blaTEM genes were evaluated by polymerase chain reaction (PCR).

Results:

In total, 817 presumptive strains were obtained from xylose lysine deoxycholate and SalmonellaShigella agars and subcultured on xylose-lysine-tergitol 4 and MacConkey agars, from which 150 strains were isolated; 29 of these strains were presumptive for Salmonella spp. after performing biochemical tests and 16 were confirmed by PCR as Salmonella Infantis (15) and Gallinarum (1). All strains were found to be multiresistant to antibiotics, showing three different profiles and isolates resistant to cefotaxime, and the blaCTX-M gene was detected.

Conclusion:

This is the first study to isolate S. Infantis from broiler litter in Colombia. All isolates exhibited resistance to the evaluated antimicrobials, suggesting the misuse of antimicrobials in small- and medium-sized poultry farms. The presence of Salmonella enterica serovar Infantis is a public health problem. Thus, regular monitoring of poultry litter is recommended, as these bacteria can be transmitted to humans through animal products or contaminated environments.

Can Biochar Improve the Sustainability of Animal Production?

Animal production is a significant contributor of organic and inorganic contaminants in air, soil, and water systems. These pollutants are present beginning in animal houses and impacts continue through manure storage, treatment, and land application. As the industry is expected to expand, there is still a lack of affordable, sustainable solutions to many environmental concerns in animal production. Biochar is a low-cost, sustainable biomaterial with many environmental remediation applications. Its physicochemical properties have been proven to provide environmental benefits via the adsorption of organic and inorganic contaminants, promote plant growth, improve soil quality, and provide a form of carbon sequestration. For these reasons, biochar has been researched regarding biochar production, and application methods to biological systems have a significant influence on the moisture content, pH, microbial communities, and carbon and nitrogen retention. There remain unanswered questions about how we can manipulate biochar via physical and chemical activation methods to enhance the performance for specific applications. This review article addresses the positive and negative impacts of biochar addition at various stages in animal production from feed intake to manure land application.

Impact of Waste Tea Litter on NH3 and CO2 Emissions during Broiler Rearing

Pollution generated by livestock and poultry rearing is an important environmental issue, and gas emissions during animal production are continuously increasing. A digital rearing chamber inspection system was designed in the present study in order to examine the waste tea litter’s impact on the growth performance and harmful gas emissions, such as ammonia (NH3) and carbon dioxide (CO2), during broiler rearing. Broilers were raised without litter and with waste tea litter. According to the results, broiler growth showed little difference between the two groups during the experimental period, and it was concluded that waste tea litter had no impact on broiler growth. Meanwhile, the gas emissions of the waste tea-litter group were lower than the non-bedding-materials group. In detail, the average concentrations of NH3 and CO2 of the non-bedding-materials group were 9.33 ± 3.65 ppm and 797 ± 107 ppm, respectively; while these concentrations in the waste-tea-litter group were 1.01 ± 0.35 ppm and 713 ± 69 ppm, respectively. According to the analysis of the litter properties, it was suggested that waste tea litter can reduce the moisture content in litter, and affect microbial and urease activity due to its low carbon nitrogen ratio (C/N), weak acid, and porous structure characteristics. In conclusion, this study showed the potential of waste tea litter in NH3 and CO2 emission reduction during broiler rearing.

Odour Emissions from Livestock Buildings

Due to the intensification and concentration of agriculture and the interpenetration of residential and agricultural areas, odours are an important air pollutant. The changes taking place in rural areas mean that not all inhabitants of these areas are involved in agricultural activities, and there are new people looking for an idyllic life in the countryside. In recent years, there has been an increase in the number of complaints concerning odour emissions from agricultural sources. The aim of the study was to compare odour emissions from selected livestock buildings for various animal species in the Great Poland Voivodeship. The assessment of odour concentrations was made in accordance with EN 13725: 2003 using the TO 8 olfactometer in the accredited olfactometric laboratory of the Institute of Technology and Life Sciences National Research Institute in Poznań. The fattening house showed the highest odour burden for the surroundings (mean odour concentration and odour emission factor: 450 ouE·m3 and 0.419 ouE·s−1·kg−1, respectively). In the case of buildings for poultry and dairy cows, the differences in the emission factors were not large. The emission factor for poultry (0.232 ouE·s−1·kg−1) was 22% higher than that for dairy cows (0.190 ouE·s−1·kg−1). Conversely, the mean concentration in the hen house (281 ouE·m3) was 18% lower than that in the dairy cow barn (342 ouE·m3).

Impact of poultry litter Salmonella levels and moisture on transfer of Salmonella through associated in vitro generated dust

Dust present in poultry houses can contain high concentrations of microorganisms and has the potential to include pathogens from the litter. The objective of this study was to examine in vitro the potential for litter to dust transfer of aerobic bacteria, Salmonella, E. coli, and coliforms, and the role of the litter moisture on this process. Poultry litter was inoculated with 10² to 10⁹ CFU/mL of Salmonella Typhimurium to evaluate litter to dust transfer of bacteria (Experiment 1). To evaluate the effect of litter moisture on litter to dust microbial transfer (Experiment 2), litter was inoculated with 10⁹S. Typhimurium with increasing amounts of sterilized water added for moisture adjustment. Dust was generated by blowing air in a direct stream onto inoculated litter while simultaneously collecting dust through impingement. Following litter and dust sample collection, microbial analyses for aerobic plate counts (APC),Salmonella, E. coli, and coliforms were conducted. Both experiments were repeated 5 times and their data analyzed by one-way ANOVA and simple logistic regression. In Experiment 1, APC of litter (log₁₀ CFU/g) and dust samples (log₁₀ CFU/L) were 10.55 and 4.92, respectively. Salmonella ranged from 1.70 to 6.16 log₁₀ CFU/g in litter and only one dust sample had 1.10 log₁₀ CFU/L of Salmonella. As Salmonella levels in litter increased, the probability of obtaining a dust Salmonella positive result also increased. In Experiment 2, attained moisture percentages were 13.0, 18.2, 23.0, 28.2, and 33.3%. Litter recovery for APC, Salmonella, E. coli, and coliforms counts did not differ (P > 0.05) with increasing moisture levels. Dust sample bacterial counts significantly decreased with increasing moisture levels (P < 0.0001). Results from this in vitro study indicate that there is potential for Salmonella to be present in generated dust and the higher levels of Salmonella in litter increase the likelihood of detecting Salmonella in dust. Additionally, with higher litter moisture percentage, prevalence of Salmonella in generated dust was decreased.

Review of litter turning during a grow-out as a litter management practice to achieve dry and friable litter in poultry production

Maintaining dry litter that chickens can “work” is a key objective for successful meat chicken production as it reduces the likelihood of health and welfare issues by breaking down and working excreta and contributing to the water evaporation process. Litter turning is a practice that may help reduce moisture content within the litter by accelerating the drying process when it is combined with effective ventilation. However, information and research about the practice and the effects it could have on the health and well-being of meat chickens (broilers) are minimal. A recent survey of Australian meat chicken growers reiterated the concerns they have about its impact on chicken well-being, but it also demonstrated how growers thought it could enhance the effectiveness of their operation. The aim of this review paper is to identity information relevant to litter turning and the potential effects of this practice on litter quality, ammonia emissions, litter moisture, and animal welfare. This review demonstrates the need for additional research to validate perceptions and address potential concerns and impacts that this practice may have on broiler production. Closing this knowledge gap will improve litter turning practices leading to safer and more consistent outcomes.

Assessment of gaseous ozone treatment on Salmonella Typhimurium and Escherichia coli O157:H7 reductions in poultry litter

Poultry litter is used as soil amendment or organic fertilizer. While poultry litter is enriched with organic matter suitable for land, the presence of pathogens such as Salmonella in poultry litter is a concern. To investigate the effect of gaseous ozone on pathogen reductions in poultry litter, this study conducted a series of experiments that involved understanding of Salmonella Typhimurium and Escherichia coli O157:H7 inactivation at various doses of Ozone (O₃) in wet and dry poultry litter conditions. Previously, ozone treatment has been shown to disinfect the surface of foods and plant materials including fruits, juices, and wastewater, however, additional research are needed to better understand the impacts of ozone on treatment of soil amendments. Sanitizing methods capable of eliminating pathogens of soil amendments are crucial to mitigate disease outbreaks related with litter/manure-based fertilizers. In this study, a bench scale continuous ozone treatment system was designed to produce O₃ gas, with a range O₃ concentrations (7.15-132.46 mg·L^-1), monitor ozone concentrations continuously, and control the ozone exposure time (15 to 90 mins) to understand the effectiveness of O₃ in eliminating S. Typhimurium and E. coli O157:H7 in poultry litter. Results showed that 7.15 mg·L^-1 did not reduce the counts of S. Typhimurium until exposure to O₃ for 90 min. The O₃ concentrations of 43.26 ~ 132.46 mg·L^-1 exposure reduced the bacterial counts. Furthermore, the moisture content of poultry litter was found to be an influencing factor for pathogen reduction. The pathogen reduction rates were reduced when the moisture content was increased. At higher moisture content, high concentrations of O₃ (132.46 mg·L^-1) were needed for pathogen reductions. The moisture content of 30% or lower was found to be more effective for controlling pathogen levels in poultry litter. Our study demonstrates that gaseous O₃ treatment could be used as an additional decontamination technique to ensure the certain degree of microbiological safety of poultry litter based soil amendment.

Volatile Cues Influence Host-Choice in Arthropod Pests

Many arthropod pests of humans and other animals select their preferred hosts by recognising volatile odour compounds contained in the hosts' 'volatilome'. Although there is prolific literature on chemical emissions from humans, published data on volatiles and vector attraction in other species are more sporadic. Despite several decades since the identification of a small number of critical volatiles underpinning specific host-vector relationships, synthetic chemicals or mixtures still largely fail to reproduce the attractiveness of natural hosts to their disease vectors. This review documents allelochemicals from non-human terrestrial animals and considers where challenges in collection and analysis have left shortfalls in animal volatilome research. A total of 1287 volatile organic compounds were identified from 141 species. Despite comparable diversity of entities in each compound class, no specific chemical is ubiquitous in all species reviewed, and over half are reported as unique to a single species. This review provides a rationale for future enquiries by highlighting research gaps, such as disregard for the contribution of breath volatiles to the whole animal volatilome and evaluating the role of allomones as vector deterrents. New opportunities to improve vector surveillance and disrupt disease transmission may be unveiled by understanding the host-associated stimuli that drive vector-host interactions.

Properties of conventional and alternative bedding materials for dairy cattle

The bedding material used in barns for dairy cows has a significant effect on animal welfare and performance. Bedding influences the duration in which animals remain lying down and, consequently, the processes of rumination and milk production. It is crucial to have a complete understanding of the properties of bedding materials and the effects of alternative bedding materials on dairy cattle. This paper aims to evaluate the physical, chemical, and biological properties of various alternative and conventional bedding materials for dairy cattle for use in compost bedded pack or freestall barn systems. We analyzed 50 samples of 17 bedding materials produced in 3 European countries. We analyzed physical properties including the water holding capacity, porosity, moisture content, bulk density, dry bulk density, and particle size. Chemical analyses were performed to determine the total N, total organic C, and C:N ratio. In the biological analyses, the Escherichia coli count, total bacteria count, coliform count, and Klebsiella spp. count were assessed. The results demonstrated how the physical properties of the bedding materials may influence the chemical and biological properties. All of the materials presented adequate chemical properties to be used as bedding material. The physical properties of the bedding materials differed widely among the materials except for the dry bulk density, which presented no difference. Moreover, the contamination of each studied microorganism was observed for each bedding material to determine which material had the lowest level of contamination. Posidonia oceanica, Miscanthus grass, and spelt husks could be considered as a potential alternative material for use as bedding material for dairy cows in both systems (i.e., composted bedded pack and freestall). This experiment illustrated the importance of performing thorough physical, chemical, and biological analyses before implementing a material as bedding for dairy cattle.

A Data-Driven Prediction Method for an Early Warning of Coccidiosis in Intensive Livestock Systems: A Preliminary Study

Coccidiosis is still one of the major parasitic infections in poultry. It is caused by protozoa of the genus Eimeria, which cause concrete economic losses due to malabsorption, bad feed conversion rate, reduced weight gain, and increased mortality. The greatest damage is registered in commercial poultry farms because birds are reared together in large numbers and high densities. Unfortunately, these enteric pathologies are not preventable, and their diagnosis is only available when the disease is full-blown. For these reasons, the preventive use of anticoccidials-some of these with antimicrobial action-is a common practice in intensive farming, and this type of management leads to the release of drugs in the environment which contributes to the phenomenon of antibiotic resistance. Due to the high relevance of this issue, the early detection of any health problem is of great importance to improve animal welfare in intensive farming. Three prototypes, previously calibrated and adjusted, were developed and tested in three different experimental poultry farms in order to evaluate whether the system was able to identify the coccidia infection in intensive poultry farms early. For this purpose, a data-driven machine learning algorithm was built, and specific critical values of volatile organic compounds (VOCs) were found to be associated with abnormal levels of oocystis count at an early stage of the disease. This result supports the feasibility of building an automatic data-driven machine learning algorithm for an early warning of coccidiosis.

Variations and environmental impacts of odor emissions along the waste stream

Odor nuisance related to municipal solid waste (MSW) disposal is one of the main incentives to counter the Not-In-My-Backyard Syndrome. Moreover, integrated odor management contributes to specific odor control at different waste treatment stages. In this study, odor emissions along typical MSW streams were categorized based on their olfactive and environmental impacts after a field investigation of the residential district (RD), transfer station (TS), and landfill (LF) in the Chongming Eco-island. It was found that odorants, especially NH₃ and sulfides, increased along the MSW stream, with total chemical concentration increasing from 1241.5 ± 235.6 to 6947.2 ± 1726.8 μg/m³. Source separation and co-landfill system, which premixes the MSW with bottom ash (BA) at a ratio of 5:1, were speculated to efficiently attenuate odorants. Sulfides reduced owing to an increase in trace metal dissolution and carbon source consumption with the addition of BA at the LF, whereas NH₃ in the leachate pond increased due to enhanced biodegradation and alkalinity. Photochemical ozone formation (6.7 × 10^-8-8.6 × 10^-5 personal equivalent, PE), nutrient enrichment (5.4 × 10^-8-4.6 × 10^-5 PE), and acidification (4.8 × 10^-8-4.1 × 10^-5 PE) were the major environmental impact categories. The priority odor pollutants screened using ternary fuzzy synthetic system could reflect the impact of olfaction and environment and greatly varied along the waste stream.

Integrated model for estimating odor emissions from civil wastewater treatment plants

The objective of this research project was the design and development of an integrated model for odor emission estimation in wastewater treatment plants. The SMAT's plant, the largest wastewater treatment facility in Italy, was used as a case study. This article reports the results of the characterization phase that led to the definition and design of the proposed conceptual model for odor emission estimation. In this phase, concentrations of odor chemical tracers (VOC, H₂S, NH₃) and odor concentrations were monitored repeatedly. VOC screening with GC-MS analysis was also performed. VOC concentrations showed significant variability in space and magnitude. NH₃ and H₂S were also detected at considerable concentrations. Results were elaborated to define a spatially variable linear relationship between the sum of odor activity values (SOAV) and odor concentrations. Based on the results, a conceptual operational model was presented and discussed. The proposed system is composed by a network of continuous measurement stations, a set of algorithms for data elaboration and synchronization, and emission dispersion modeling with the application of Lagrangian atmospheric models.

Measurements techniques and models to assess odor annoyance: A review

Odors have received increasing attention among atmospheric pollutants. Indeed, odor emissions are a common source of complaints, affecting the quality of life of humans and animals. The odor is a property of a mixture of different volatile chemical species (sulfur, nitrogen, and volatile organic compounds) capable of stimulating the olfaction sense sufficiently to trigger a sensation of odor. The impact of odors on the surrounding areas depends on different factors, such as the amount of odors emitted from the site, the distance from the site, weather conditions, topography, other than odors sensitivity and tolerance of the neighborhood. Due to the complexity of the odor issue, the aim of this review was to give an overview of: (i) techniques (sensorial and analytical) that can be used to determine a quantitative and qualitative characterization; (ii) air dispersion models applied for the evaluation of the spatial and temporal distribution of atmospheric pollutants in terms of concentration in air and/or deposition in the studied domain; (iii) major sources of odor nuisance (waste and livestock); (iv) mitigation actions against odor impact. Among sensorial techniques dynamic olfactometry, field inspection, and recording from residents were considered; whereas, for analytical methodologies: gas chromatography-mass spectrometry, identification of specific compounds, and electronic nose. Both kinds of techniques evaluate the odor concentration. Instead, to account for the effective impact of odors on the population, air dispersion models are used. They can provide estimates of odor levels in both current and future emission scenarios. Moreover, they can be useful to estimate the efficiency of mitigation strategies. Most of the odor control strategies involve measures oriented to prevent, control dispersion, minimize the nuisance or remove the odorants from emissions, such as adequate process design, buffer zones, odor covers, and treatment technologies.

Screening of single or combined administration of 9 probiotics to reduce ammonia emissions from laying hens

The effects of single/combined administration of 9 probiotics on ammonia (NH3) emissions during in vitro fermentation of the caecal contents of laying hens were studied. Not all of the probiotics reduced NH3 emissions. Pichia farinose, Bacillus coagulans, Lactobacillus plantarum, Pichia guilliermondii, and Bacillus subtilis reduced NH3 production by approximately 35.1 to 39%. Compared with the control group, the greatest NH3 inhibition was achieved via the combined application of P. guilliermondii, B. subtilis, and L. plantarum at 1:2:1, resulting in a 46% reduction. Effective probiotics use decreased crude protein digestibility, pH, ammonium nitrogen, valerate levels, and urease and uricase activity, but increased urea, purine trione, nitrate nitrogen, total volatile fatty acids, and acetate levels. The relative abundance of the bacteria responsible for fermenting carbohydrates to produce short fatty acids was increased. Under different treatments, the KEGG Orthology (KO) metabolic pathways of NH3 production and utilization were diverse. Hence, the application of probiotics to control NH3 emissions is dependent on the types and combined ratio of the organisms involved.

Biochar reduces volatile organic compounds generated during chicken manure composting

The efficiency of biochar for reducing the levels of volatile organic compounds (VOC) was investigated in a composting mixture containing 90% poultry manure and 10% straw (with and without 3% biochar addition) at three different stages of the process. The use of a low application rate of biochar reduced the concentration of VOC during the thermophilic phase. Biochar significantly reduced the levels of nitrogen volatile compounds, which are the most abundant VOC family, originated from microbial transformation of the N-compounds originally present in manure. The most efficient VOC reduction was observed in oxygenated volatile compounds (ketones, phenols and organic acids), which are intermediates of organic matter degradation, whereas there was no effect on other VOC families (aliphatic, aromatic and terpenes). These results suggest the importance of not only the sorption capacity of biochar but also its impact in the composting progress as main drivers for VOC reduction.

Why did severe feather pecking and cannibalism outbreaks occur? An unintended case study while investigating the effects of forage and stress on pullets during rearing

This 2 × 2 factorial experiment aimed to investigate the effects of stimulating foraging behavior from wk 6 and imposed stress at wk 16 on the development of severe feather pecking (SFP) in chickens reared for free-range egg production. Non-beak-trimmed ISA Brown chicks were purchased at one day old and floor-reared on wood shavings. From wk 6, straw was provided daily in dispensers (Forage vs. No forage) to stimulate foraging. At wk 15, there were 16 pens of 50 pullets. "Stressors" were applied to half the pens in wk 16 via combined transport, relocation, and mixing (TRM) of pullets, simulating activities around transfer from the rearing to egg-laying farm (TRM vs. Not TRM). Range access was permitted from wk 21. Behavior, plumage damage (PD), growth, egg production, feed use, injuries, and mortalities were recorded, along with litter moisture and pH. In wk 26, an SFP outbreak commenced. By wk 34, PD was worse in south- than north-aspect pens (P < 0.001). Further, PD was more affected by side of the shed than the experimental treatments. In wk 30, an outbreak of injurious pecking (IP) commenced in the 4 TRM-treatment pens on the south side, with IP deaths almost 3 times more common in the Forage+TRM than No forage+TRM treatment. We suggest factors associated with a 13-day rainfall event that occurred in late winter predisposed the flock to SFP. While multiple factors such as winter cold, muddy ranges, damp floor litter with elevated pH, among others coincided, hens were clearly more impacted in south- than north-aspect pens. Once initiated, SFP possibly spread via social learning, and by wk 40, ∼98% of hens had PD. Interestingly, the IP outbreak was related to a combination of factors (stressors?), such as being housed in colder, damper south-aspect pens (note: southern hemisphere), having added Forage, and TRM. These unexpected relationships could help direct future research to identify the specific factors involved in the causation of SFP and IP/cannibalism outbreaks.

Effectiveness of poultry litter amendments on bacterial survival and Eimeria oocyst sporulation

AIM

Broilers' optimum performance in response to their genetic potential depends on litter environment which is ideal for bacterial survival and coccidian oocyst sporulation. An in vitro evaluation was conducted for the effectiveness of superphosphate, meta-bisulfide, and charcoal litter amendments in minimizing Escherichia coli O157:H7 and Salmonella Typhimurium survival, Eimeria oocyst count, and sporulation.

MATERIALS AND METHODS

Three groups of 16 litter trays were prepared and inoculated with E. coli O157:H7, S. Typhimurium, and Eimeria non-sporulated oocyst. A set of four trays in each group was designed for each one of the chemical amendments. A total of 720 litter samples were collected and examined for bacterial counts, Eimeria oocyst count, and sporulation during the experimental period (35 days).

RESULTS

Litter moisture and pH revealed a highly significant (p<0.001) reduction in all treated litter trays compared to control. Total bacterial count (TBC), total Enterobacteriaceae count, and S. Typhimurium count showed a highly significant (p<0.001) reduction in meta-bisulfide-treated trays compared to other amendments and positive control. Meanwhile, Eimeria oocyst count and sporulation revealed a highly significant (p<0.001) reduction in superphosphate, meta-bisulfide, and charcoal-treated trays, respectively. Temperature revealed a highly significant (p<0.001) weak positive correlation with pH of all inoculated trays, a highly significant (p<0.001) weak negative correlation with moisture percentage of E. coli O157:H7 and S. Typhimurium inoculated trays, and a highly significant (p<0.001) weak negative correlation with TBC. Meanwhile, relative humidity revealed significant (p≤0.005) weak positive correlation with moisture percentage of E. coli O157:H7 inoculated trays.

CONCLUSION

The study concluded that regular usage with periodical reapplication of litter amendments as meta-bisulfide or superphosphate in poultry farms is one of the indispensable managemental and preventive measures for minimizing bacterial survival and inhibiting Eimeria oocyst maturation and sporulation.

Ammonia Oxidizers in a Grazing Land with a History of Poultry Litter Application

Poultry litter (PL) is widely applied on grazing lands in Georgia. However, it is not clear how its long-term use affects soil microorganisms and their function. We examined changes in activity and community structure of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in a grazing land with a history of PL application and compared it to treatment with urea ammonium nitrate (UAN). Soil samples (0-15 cm) were collected in 2009 (after 15 yr of PL application) and in 2013 (after 2 yr of no application). The abundance and community composition of ammonia oxidizers (AO) were determined with molecular techniques that targeted Nitrification potential (NP) was used for measuring their activity. Abundance of AO was significantly higher in PL (7.41 and 7.10 log copies g soil for AOB and AOA, respectively) than in UAN plots (6.82 and 6.50 log copies g soil for AOB and AOA, respectively) in 2009. This is consistent with NP, which was higher in PL (0.78 mg NO -N kg h) than in UAN (0.50 mg NO-N kg h) plots in 2009. The abundance of AO and NP decreased in 2013. There was no treatment effect on the composition of AO. Correlation analysis suggested that AOB were functionally more important than AOA, indicating the need to target AOB for efficient management of N in PL-receiving soils. Overall, the difference in nitrification between PL and UAN was mainly caused by the change in AO abundance rather than composition, and AO were not negatively affected by an increase in PL-derived trace metal concentrations.

Odorous Compounds from Poultry Manure Induce DNA Damage, Nuclear Changes, and Decrease Cell Membrane Integrity in Chicken Liver Hepatocellular Carcinoma Cells

Animal breeding and management of organic wastes pose a serious problem to the health of livestock and workers, as well as the nearby residents. The aim of the present study was to determine the mechanisms of toxicity of selected common odorous compounds from poultry manure, including ammonia, dimethylamine (DMA), trimethylamine (TMA), butyric acid, phenol, and indole. We measured their genotoxic and cytotoxic activity in the model chicken cell line (LMH), in vitro, by comet assay and lactate dehydrogenase assay, respectively. We also made microscopic observations of any morphological changes in these cells by DAPI staining. Four compounds, namely ammonia, DMA, TMA, and butyric acid increased DNA damage in a dose-dependent manner (p < 0.05), reaching genotoxicity as high as 73.2 ± 1.9%. Phenol and indole induced extensive DNA damage independent of the concentration used. Ammonia, DMA, and TMA caused a dose-dependent release of lactate dehydrogenase (p < 0.05). The IC₅₀ values were 0.02%, 0.05%, and 0.1% for DMA, ammonia and TMA, respectively. These compounds also induced nuclear morphological changes, such as chromatin condensation, shrinkage, nuclear fragmentation (apoptotic bodies), and chromatin lysis. Our study exhibited the damaging effects of odorous compounds in chick LMH cell line.

A rich-amine porous organic polymer: an efficient and recyclable adsorbent for removal of azo dye and chlorophenol

A novel rich-amine porous organic polymer (RAPOP) was synthesized via the Schiff base reaction with melamine (MA) and terephthalaldehyde (TA) as the monomers.