Swine Concentrated Animal Feeding Operations Research Articles

From pollution to resource: advancing swine waste treatment in the USA

Concentrated animal feeding operations (CAFOs) have led to environmental challenges, specifically waste management. Swine CAFOs generate large amounts of waste, requiring proper treatment to avoid air and water pollution. Conventional waste management technologies, such as lagoon and spray field systems, do not prevent air and water pollution impacts. Research for the past few decades led to recommendations for waste treatment technologies superior to lagoons and spray fields. Private environmental sustainability initiatives focused on reducing greenhouse gas emissions in the food supply chain have implemented biogas digester projects for capturing methane in covered swine lagoons to reduce greenhouse gas emissions. However, research indicates that methane capture alone does not solve the broader pollution issues associated with lagoon and spray field systems still in use at these CAFOs to dispose of digested effluents. The Environmentally Superior Technologies (EST) initiative in North Carolina set public standards to eliminate waste discharge, reduce atmospheric emissions, and control odors and pathogens. Research has confirmed that technologies coupling solids separation with water treatments to remove volatile organic carbon, pathogens, and reactive forms of nitrogen can meet EST standards. A designated EST—the Super Soil System—substantially reduced odor by 99.9%; pathogens by 99.99%, nutrients (phosphorus and nitrogen) by >90%, and heavy metals (cooper and zinc) by 99%. The ammonia emissions were reduced by 94.4% for the warm and 99.0% for the cool season with respect to a conventional lagoon system. Corresponding greenhouse gas emission reductions were 96.7%. Components of designated EST can be applied to retrofit covered lagoons and anaerobic digestion systems with significant environmental benefits. Recommendations are proposed, based on the collective experience with EST and current trends in animal production concentration, for environmentally safe technologies to handle excess manure produced in the USA.

Zinc Protects against Swine Barn Dust-Induced Cilia Slowing.

Agricultural workers exposed to organic dust from swine concentrated animal feeding operations (CAFOs) have increased chances of contracting chronic lung disease. Mucociliary clearance represents a first line of defense against inhaled dusts, but organic dust extracts (ODEs) from swine barns cause cilia slowing, leading to decreased bacterial clearance and increased lung inflammation. Because nutritional zinc deficiency is associated with chronic lung disease, we examined the role of zinc supplementation in ODE-mediated cilia slowing. Ciliated mouse tracheal epithelial cells were pretreated with 0-10 µg/mL ZinProTM for 1 h, followed by treatment with 5% ODE for 24 h. Cilia beat frequency (CBF) and protein kinase C epsilon (PKCε) activity were assayed. ODE treatment resulted in cilia slowing after 24 h, which was reversed with 0.5 and 1.0 µg/mL ZinPro pre-treatment. No zinc protection was observed at 50 ng/mL, and ciliated cells detached at high concentrations (100 µg/mL). ZinPro alone produced no changes in the baseline CBF and showed no toxicity to the cells at concentrations of up to 10 µg/mL. Pre-treatment with ZinPro inhibited ODE-stimulated PKCε activation in a dose-dependent manner. Based on ZinPro's superior cell permeability compared to zinc salts, it may be therapeutically more effective at reversing ODE-mediated cilia slowing through a PKCε pathway. These data demonstrate that zinc supplementation may support the mucociliary transport apparatus in the protection of CAFO workers against dust-mediated chronic lung disease.

211 Analysis of microbial communities from a commercial-size swine manure pit and their association with production of volatile organic compounds

Abstract Global pollution and emission concerns have been linked to concentrated animal feeding operations (CAFOs). Indeed, the U.S Environmental Protection Agency (US EPA) warns that there is a significant danger to human health, soil, and water quality from CAFOs. Volatile organic compounds (VOCs), which are amongst air contaminants that pose a serious risk, are abundantly produced in swine manure pits. While VOC emissions from swine manure have been well studied, the microbial species responsible for their production remain mostly uncharacterized. Thus, a deeper comprehension of the microorganisms responsible for VOC production in swine manure pits may help in the development of management approaches that target the microbiome in these environments. In this context, this study aimed to identify the major bacterial species populating the manure pit of a commercial-size swine wean-to-finish research facility. Manure collected from two sampling locations at different time points were analyzed using the 16S rRNA gene through PCR-amplification of the V1-V3 regions from microbial genomic DNA, followed by Illumina MiSeq 2X300 sequencing. An analysis of the most highly represented microorganisms identified 24 bacterial Operational Taxonomic Units (OTUs), with only four showing a species-level nucleotide sequence identity to currently known or valid species. As these results indicated that the majority of bacterial species from this manure pit were unknown, a metagenomics approach was used to assemble partial to full length genomes from the two most abundant OTUs: Pit_9-00239 [5.09% - 19.44%; Clostridium saccharoperbutylacetonicum (96.60%)] and Pit_ 7-00035 [5.58% - 17.30%; Bacteroides eggerthii (87.66%)]. From genome assembly analysis, 979 contigs were generated for a combined length of 12,367,510 bp, which together included 21,776 coding sequences. Predicted metabolic functions from these contig sets included pathways involved in carbohydrate utilization (glycolysis), vitamin synthesis (riboflavin), and butyrate production (volatile fatty acids). Notably, an enzyme responsible for the production of indole, a common VOC produced from swine manure pits, was also identified. Together, the results from this analysis provide insights on metabolic capabilities of abundant bacterial species from manure pits. These can in turn be used for the future development of management strategies or products that can reduce VOC emissions that result from swine CAFO manure storage.

Agricultural dust derived bacterial extracellular vesicle mediated inflammation is attenuated by DHA

Dietary long-chain omega-3 polyunsaturated fatty acids (n-3 PUFA) and their pro-resolving metabolites are protective against atherosclerotic disease, and ameliorate systemic inflammatory conditions including lupus erythematosus, psoriasis, and bronchial asthma. Organic bioaerosol inhalation is a common and injurious hazard associated with agricultural occupations such as work in swine concentrated animal feeding operations (CAFOs) and is known to increase the risk for developing respiratory conditions such as asthma and COPD. Nearly all cells secrete membrane-bound vesicles (extracellular vesicles, EVs) that have the capacity to transmit protein, nucleic acid, and lipid signaling mediators between cells. Using a polymer-based isolation technique (ExoQuick, PEG) followed by ultracentrifugation, EVs were isolated from CAFO dust extracts, and were quantified and partially characterized. Here, we investigated the role of the n-3 PUFA docosahexaenoic acid (DHA) as a component of n-6 to n-3 PUFA mixtures used to recapitulate physiologically relevant dietary ratios in the resolution of inflammatory injury caused by exposure to EVs carried by agricultural organic dust in vitro. Primary human bronchial epithelial cells, fibroblasts and monocyte-derived macrophages were exposed to EVs isolated from swine CAFO dust. Cells were treated with mixtures of n-6 and n-3 PUFA during recovery from the EV-induced injury. CAFO dust extract (DE) was found to contain EVs that contributed significantly to the overall consequences of exposure to complete DE. DHA-rich PUFA ratios inhibited DE-derived EV-induced proinflammatory cytokine release dose-dependently. DHA-rich PUFA ratios also reversed the damaging effects of EVs on recellularization of lung matrix scaffolds, accelerated wound healing, and stimulated the release of pro-resolution mediators. These results underscore the importance of n-3 PUFA as anti-inflammatory compounds during recovery from EV-laden environmental dust exposure in the context of cellular responses in vitro, warranting future translational studies.

Exposure to industrial hog operations and gastrointestinal illness in North Carolina, USA

With 9 million hogs, North Carolina (NC) is the second leading hog producer in the United States. Most hogs are housed at concentrated animal feeding operations (CAFOs), where millions of tons of hog waste can pollute air and water with fecal pathogens that can cause diarrhea, vomiting, and/or nausea (known as acute gastrointestinal illness (AGI)). We used NC's ZIP code-level emergency department (ED) data to calculate rates of AGI ED visits (2016–2019) and swine permit data to estimate hog exposure. Case exposure was estimated as the inverse distances from each hog CAFO to census block centroids, weighting with Gaussian decay and by manure amount per CAFO, then aggregated to ZIP code using population weights. We compared ZIP codes in the upper quartile of hog exposure (“high hog exposed”) to those without hog exposure. Using inverse probability of treatment weighting, we created a control with similar demographics to the high hog exposed population and calculated rate ratios using quasi-Poisson models. We examined effect measure modification of rurality and race using adjusted models. In high hog exposed areas compared to areas without hog exposure, we observed a 11% increase (95% CI: 1.06, 1.17) in AGI rate and 21% increase specifically in rural areas (95% CI: 0.98, 1.43). When restricted to rural areas, we found an increased AGI rate among American Indian (RR = 4.29, 95% CI: 3.69, 4.88) and Black (RR = 1.45, 95% CI: 0.98, 1.91) residents. The association was stronger during the week after heavy rain (RR = 1.41, 95% CI: 1.19, 1.62) and in areas with both poultry and swine CAFOs (RR = 1.52, 95% CI: 1.48, 1.57). Residing near CAFOs may increase rates of AGI ED visits. Hog CAFOs are disproportionally built near rural Black and American Indian communities in NC and are associated with increased AGI most strongly in these populations.

Wastewater Treatment Using Novel Magnetic Nanosponges

Modern agricultural activities and concentrated animal feeding operations (CAFOs) are two of the major sources of groundwater contamination that affect the quality of drinking water. Conventional water quality improvement methods include direct filtration, coagulation/settling treatment techniques, membrane-based systems, and absorption-based systems. However, to date, there are no efficient and cost-effective processes available for water treatment. This study developed an innovative nanotechnology-based technique to improve groundwater quality. Magnetic nanosponges (MNSs) were synthesized and characterized using two different magnetic nanoparticles along with polymeric coagulants. The efficiency of MNSs in removing pollutants in wastewater collected from local diary and swine CAFO lagoons was investigated. Standard water quality evaluation parameters, such as the total organic content (TOC), turbidity, total suspended solids (TSS), and biological oxygen demand (BOD), were measured prior to and after treatment with MNSs. The results demonstrate the potential of MNSs to improve the quality of groundwater and support the development of a cost-effective best management practice (BMP) that also employs traditional coagulants at CAFOs and other wastewater treatment plants.

High-frequency assessment of air and water quality at a concentration animal feeding operation during wastewater application to spray fields

Air and water quality at a concentrated animal feeding operation (CAFO) in Eastern North Carolina that uses a covered lagoon and anaerobic digester was evaluated for 2 weeks in August 2020. Real-time PM2.5 mass concentrations were determined using a reference ADR-1500 nephelometer and high-frequency measurements of dissolved inorganic nitrogen (DIN) were evaluated using autonomously logging sensors. Air and water quality parameters were assessed before, during and after wastewater from the lagoon was irrigated onto adjacent spray fields. Reference measurements were conducted alongside a HOBO weather station to collect real-time wind speed and direction, temperature, and humidity measurements. PM2.5 concentrations varied between 0 and 159 μg/m3 with an average concentration of 11 μg/m3, below EPA standard for secondary aerosols of 15 μg/m3. Higher PM2.5 concentrations were observed when wind originated from swine barns but not from covered lagoons. Water quality data showed that DIN concentrations downgradient from the CAFO were elevated relative to upstream concentrations. A groundwater seep that drains a spray field contained the highest average DIN concentration (31.0 ± 12.8 mg L−1), which was 25 times greater than upstream DIN concentrations (1.2 ± 0.8 mg L−1). Average DIN concentration at the downstream station was lower than the seep concentration (8.6 ± 16.2 mg L−1), but approximately 8 times greater than upstream. Air quality data show that the lagoon cover was effective at mitigating air quality degradation, whereas DIN concentrations in water were similar to previous studies on CAFOs using open lagoons. In addition, air and water quality parameters were significantly (p < 0.001) higher after irrigation, indicating possible influence due to ammonia and nitrate elevation. Additional research is needed to compare high-frequency data collected from swine CAFOs using capped and uncapped lagoon systems to better understand spatiotemporal air and water quality trends of this practice.

Characterizing the soil microbiome and quantifying antibiotic resistance gene dynamics in agricultural soil following swine CAFO manure application.

As agriculture industrializes, concentrated animal feeding operations (CAFOs) are becoming more common. Feces from CAFOs is often used as fertilizer on fields. However, little is known about the effects manure has on the soil microbiome, which is an important aspect of soil health and fertility. In addition, due to the subtherapeutic levels of antibiotics necessary to keep the animals healthy, CAFO manure has elevated levels of antibiotic resistant bacteria. Using 16s rRNA high-throughput sequencing and qPCR, this study sought to determine the impact of swine CAFO manure application on both the soil microbiome and abundance of select antibiotic resistance genes (ARGs) and mobile element genes (erm(B), erm(C), sul1, str(B), intI1, IncW repA) in agricultural soil over the fall and spring seasons. We found the manure community to be distinct from the soil community, with a majority of bacteria belonging to Bacteroidetes and Firmicutes. The soil samples had more diverse communities dominated by Acidobacteria, Actinobacteria, Proteobacteria, Verrucomicrobia, and unclassified bacteria. We observed significant differences in the soil microbiome between all time points, except between the spring samples. However, by tracking manure associated taxa, we found the addition of the manure microbiome to be a minor driver of the shift. Of the measured genes, manure application only significantly increased the abundance of erm(B) and erm(C) which remained elevated in the spring. These results suggest bacteria in the manure do not survive well in soil and that ARG dynamics in soil following manure application vary by resistance gene.

Cost-effective treatment of swine wastes through recovery of energy and nutrients

Wastes from concentrated animal feeding operations (CAFOs) are challenging to treat because they are high in organic matter and nutrients. Conventional swine waste treatment options in the U.S., such as uncovered anaerobic lagoons, result in poor effluent quality and greenhouse gas emissions, and implementation of advanced treatment introduces high costs. Therefore, the purpose of this paper is to evaluate the performance and life cycle costs of an alternative system for treating swine CAFO waste, which recovers valuable energy (as biogas) and nutrients (N, P, K+) as saleable fertilizers. The system uses in-vessel anaerobic digestion (AD) for methane production and solids stabilization, followed by struvite precipitation and ion exchange (IX) onto natural zeolites (chabazite or clinoptilolite) for nutrient recovery. An alternative approach that integrated struvite recovery and IX into a single reactor, termed STRIEX, was also investigated. Pilot- and bench-scale reactor experiments were used to evaluate the performance of each stage in the treatment train. Data from these studies were integrated into a life cycle cost analysis (LCCA) to assess the cost-effectiveness of various process alternatives. Significant improvement in water quality, high methane production, and high nutrient recovery (generally over 90%) were observed with both the AD-struvite-IX process and the AD-STRIEX process. The LCCA showed that the STRIEX system can provide considerable financial savings compared to conventional systems. AD, however, incurs high capital costs compared to conventional anaerobic lagoons and may require larger scales to become financially attractive.

The ProS Peptide of Porcine Cathelicidins Is an Active Component of Swine Concentrated Animal Feeding Operations (CAFOs) Dust that Mobilizes Calcium and Stimulates Proliferation in Human Airway Smooth Muscle Cells

Components in the dust from swine concentrated animal feeding operations (CAFOs) can induce inflammatory lung disease with features of chronic obstructive lung disease. An aqueous hogbarn dust extract (HDE) induces pro‐inflammatory responses in both airway cells in culture and in mouse airways in vivo, thus providing a starting point for identifying the dust molecules that are involved. Proteomics analysis of an EGF receptor‐activating peak from gel filtration of HDE revealed multiple fragments from the ProS peptide precursor of a subset of porcine anti‐bacterial cathelicidins. Antibodies against ProS confirmed its presence in HDE. The full‐length ProS peptide, without the N‐terminal signal peptide and the C‐terminal anti‐bacterial peptide, stimulated proliferation of human airway smooth muscle (HASM) cells assessed as [3H]thymidine incorporation. Stimulation was concentration‐dependent, with a maximal stimulation of 2‐ to 3‐fold, greater than that with EGF and somewhat less than with the G protein‐coupled receptor (GPCR) mitogen lysophosphatidic acid (LPA). ProS stimulation was blocked by the EGF receptor inhibitor AG1478 and the phospholipase C inhibitor U73122, but not by the Gq inhibitor YM‐254890 or the matrix metalloprotease inhibitor GM6001. ProS also stimulated a concentration‐dependent increase in intracellular calcium that was not blocked by AG1478 but was blocked by U73122 and by the Gq inhibitor YM‐254890. These data indicate that ProS is likely to be a novel Gq‐coupled GPCR agonist that mobilizes calcium in HASM cells via Gq activation but stimulates HASM cell proliferation through a Gq‐independent pathway involving EGF receptor activation. Whether and how the phospholipase C‐dependent calcium response may be related to the phospholipase C‐dependent proliferation response remains to be established. Further studies are in progress to identify the specific receptor and signaling pathways involved. The simultaneous formation of both an anti‐bacterial peptide to fight infection and the ProS peptide to activate EGF receptors to initiate cell proliferation and repair suggests a unique dual role for the cathelicidin precursor protein.Support or Funding InformationFunded by NIOSH 1RO1‐0H008539‐09 to DJR and UNMC Institutional Funds to MLT

Integrating remote sensing with nutrient management plans to calculate nitrogen parameters for swine CAFOs at the sprayfield and sub-watershed scales

North Carolina (NC) regulates swine concentrated animal feeding operations (CAFOs) using five-year nutrient management plans (NMPs) requiring the plant available nitrogen sprayed (PANspray) to be less than that utilized by crops (PANcrops), i.e. the PAN balance (defined as PANbal=PANspray-PANcrops) remains negative, which avoids over-spraying liquid effluent onto crops. Objectives of this research are first to characterize Duplin County sprayfields and PANbal by creating the first, open-source sprayfield spatial database created for swine CAFOs in NC (for Duplin County). Second, this paper finds that for two sub-watershed scales 199 additional catchments and 1 additional HUC12 were identified as having permitted lagoon effluent applied compared to using CAFO point locations for a total of 510 catchments and 34 HUC12s with swine CAFO sprayfields. Third, a new method disaggregates annual PANbal from NMPs using remote sensing crop data. And finally, probability that sprayfields have excess PANbal is estimated due to k, a PAN availability coefficient. The remote sensing approach finds that 9-14% of catchments in a given year and 24% of catchments over a five year period have a positive PANbal. An additional 3-4% of catchments have probability of a positive PANbal due to variability in k. This work quantifies the impact of crop rotations on of sprayfields at the catchment spatial scale with respect to PANbal and highlights some of the limitations of NMPs have for estimation of PANbal. We recommend that NMPs be permitted based on the crop rotation scenario utilizing the least PAN and that swine producer compliance to manure management practice be encouraged.

Design and Assessment of an Innovative Swine Waste to Renewable Energy System

<abstract> The greater reliance on concentrated animal feeding operations (CAFOs) for livestock production presents both environmental challenges and opportunities for renewable energy and resource recovery. In this article, the design, economics of construction and operation, and environmental process performance of an innovative swine waste to renewable energy management system are presented and discussed. The system was installed at a feeder-to-finish swine CAFO permitted for 8,640 head of swine. It is comprised of an in-ground 7,600 m³ anaerobic digester that receives the hog manure and generates biogas that is used on-site for renewable energy generation in a 65 kW microturbine. The effluent of the anaerobic digester is further treated biologically in a 4,200 m³ intermittently aerated basin, providing both organics removal and some nitrogen control. Water from that basin recharges and flushes the pits in the animal barns. The system has been operational for over two years and is efficiently converting swine manure to biogas. The biogas production rate typically fluctuates seasonally from 350 to 900 m³ d^-1. The overall chemical oxygen demand (COD) and biochemical oxygen demand (BOD) removal are 92% and 99%, respectively, while total nitrogen removal is about 77% and total phosphorous removal is 82%. Thus far, carbon offset and Renewable Energy Certificate (REC) production have averaged 2485 offsets and 385 RECs per year when running without issue. The overall cost per 1,000 kg of steady-state live weight (SSLW) per year was estimated at $462, a value that is competitive as an environmentally superior technology. Overall, this large-scale project illustrates the significant potential of this system while simultaneously highlighting the important economic challenges of waste-to-energy bioprocesses.

Pigs in Space: Determining the Environmental Justice Landscape of Swine Concentrated Animal Feeding Operations (CAFOs) in Iowa.

Given the primacy of Iowa in pork production for the U.S. and global markets, we sought to understand if the same relationship with traditional environmental justice (EJ) variables such as low income and minority populations observed in other concentrated animal feeding operation (CAFO) studies exists in the relationship with swine CAFO densities in Iowa. We examined the potential for spatial clustering of swine CAFOs in certain parts of the state and used spatial regression techniques to determine the relationships of high swine concentrations to these EJ variables. We found that while swine CAFOs do cluster in certain regions and watersheds of Iowa, these high densities of swine are not associated with traditional EJ populations of low income and minority race/ethnicity. Instead, the potential for environmental injustice in the negative impacts of intensive swine production require a more complex appraisal. The clustering of swine production in watersheds, the presence of antibiotics used in swine production in public waterways, the clustering of manure spills, and other findings suggest that a more literal and figurative “downstream” approach is necessary. We document the presence and location of antibiotics used in animal production in the public waterways of the state. At the same time, we suggest a more “upstream” understanding of the structural, political and economic factors that create an environmentally unjust landscape of swine production in Iowa and the Upper Midwest is also crucial. Finally, we highlight the important role of publicly accessible and high quality data in the analysis of these upstream and downstream EJ questions.

Doctor-diagnosed health problems in a region with a high density of concentrated animal feeding operations: a cross-sectional study

BackgroundThere is growing interest in health risks of residents living near concentrated animal feeding operations (CAFOs). Previous research mostly focused on swine CAFOs and self-reported respiratory conditions. The aim was to study the association between the presence of swine, poultry, cattle and goat CAFOs and health of Dutch neighbouring residents using electronic medical records from general practitioners (GPs).MethodsData for the year 2009 were collected of 119,036 inhabitants of a rural region with a high density of CAFOs using information from GIAB (high exposed population). A comparison was made with GP data from 78,060 inhabitants of rural areas with low densities of CAFOs (low exposed population). Associations between the number of CAFOs near residents’ homes and morbidity were determined by multilevel (cross-classified) logistic regression.ResultsIn 2009, the prevalence of most respiratory and gastrointestinal conditions was similar in the high and low exposed population. Exceptions were pneumonia, atopic eczema and unspecified infectious diseases with an increased prevalence, and sinusitis with a decreased prevalence in the high exposed population. Within the high CAFO density region, the number of poultry, cattle and swine CAFOs near residents’ homes was not associated with allergic, respiratory or gastrointestinal conditions. Conversely, each additional goat CAFO within the postal code area of residents’ homes significantly increased the odds of unspecified infectious disease and pneumonia by 87 and 41 percent, respectively.ConclusionsUsing GP records, pneumonia and unspecified infectious diseases were positively associated with the number of goat CAFOs near residents’ homes, but no association was found between swine, cattle, and poultry CAFOs and respiratory, allergic or gastrointestinal conditions.Electronic supplementary materialThe online version of this article (doi:10.1186/s12940-016-0123-2) contains supplementary material, which is available to authorized users.

CALPUFF and CAFOs: Air Pollution Modeling and Environmental Justice Analysis in the North Carolina Hog Industry

Concentrated animal feeding operations (CAFOs) produce large amounts of animal waste, which potentially pollutes air, soil and water and affects human health if not appropriately managed. This study uses meteorological and CAFO data and applies an air pollution dispersion model (CALPUFF) to estimate ammonia concentrations at locations downwind of hog CAFOs and to evaluate the disproportionate exposure of children, elderly, whites and minorities to the pollutant. Ammonia is one of the gases emitted by swine CAFOs and could affect human health. Local indicator of spatial autocorrelation (LISA) analysis uses census block demographic data to identify hot spots where both ammonia concentrations and the number of exposed vulnerable population are high. We limit our analysis to one watershed in North Carolina and compare environmental justice issues between 2000 and 2010. Our results show that the average ammonia concentrations in hot spots for 2000 and 2010 were 2.5–3-times higher than the average concentration in the entire watershed. The number of people living in the areas where ammonia concentrations exceeded the minimal risk level was 3647 people in 2000 and 3360 people in 2010. We recommend using air pollution dispersion models in future environmental justice studies to assess the impacts of the CAFOs and to address concerns regarding the health and quality of life of vulnerable populations.

The omega-3 fatty acid docosahexaenoic acid attenuates organic dust-induced airway inflammation.

Workers exposed to organic dusts from concentrated animal feeding operations (CAFOs) are at risk for developing airway inflammatory diseases. Available preventative and therapeutic measures for alleviating dust-induced lung disease are inadequate. Because omega-3 fatty acids can mitigate inflammatory processes, we aimed to determine whether nutritional supplementation with the omega-3 fatty acid docosahexaenoic acid (DHA) could reduce the airway inflammatory consequences of exposures to organic dust. Aqueous extracts of organic dusts from swine CAFOs (ODE) were utilized. In DHA-pretreated human bronchial epithelial cells, lung fibroblasts, monocyte cell cultures, and precision-cut murine lung slices, we found that DHA pretreatment dose-dependently decreased ODE-induced inflammatory cytokine production. To determine the in vivo significance of DHA, C57BL/6 mice were orally administered DHA for seven days prior to treatment with intranasal ODE or saline inhalations. Animals treated with 2 mg DHA demonstrated significant reductions in ODE-induced bronchial alveolar lavage neutrophil influx and pro-inflammatory cytokine/chemokine production compared to mice exposed to ODE alone. Collectively, these data demonstrate that DHA affects several lung cells to reduce the airway inflammatory response to organic dust exposures. Dietary supplementation with DHA may be an effective therapeutic strategy to reduce the airway inflammatory consequences in individuals exposed to agriculture dust environments.

Hepatitis E virus and coliphages in waters proximal to swine concentrated animal feeding operations

North Carolina is the second leading state in pork production in the United States, with over 10 million swine. Swine manure in NC is typically collected and stored in open-pit lagoons before the liquid waste is sprayed onto agricultural fields for disposal. Components of this waste may be able to impact surface water quality with the potential for human exposure. This study examined viruses of public health concern in creeks adjacent to swine concentrated animal feeding operation (CAFO) spray fields. Surface water samples (n=154) were collected from public access waters in proximity to swine CAFO spray fields for six months and were tested for hepatitis E virus (HEV) and coliphages. HEV was detected in one sample. Somatic coliphages were detected in 98% of samples (geometric mean 24±4.1PFU per 100ml), and F+ coliphages were detected in 85% of samples (geometric mean 6.8±5.0PFU per 100ml). Only 3% (21) of the F+ coliphage isolates were RNA phage, and all of the F+ RNA coliphages belonged to genogroup I. Although the pervasiveness of swine CAFOs in this area prevented a comparison with samples from un-impacted sites, the near ubiquity of coliphages, as well as the presence of HEV, suggests that current waste management practices may be associated with the dissemination of viruses of public health concern in waters proximal to CAFO spray fields.

CAMP-dependent protein kinase activation decreases cytokine release in bronchial epithelial cells.

Lung injury caused by inhalation of dust from swine-concentrated animal-feeding operations (CAFO) involves the release of inflammatory cytokine interleukin 8 (IL-8), which is mediated by protein kinase C-ε (PKC-ε) in airway epithelial cells. Once activated by CAFO dust, PKC-ε is responsible for slowing cilia beating and reducing cell migration for wound repair. Conversely, the cAMP-dependent protein kinase (PKA) stimulates contrasting effects, such as increased cilia beating and an acceleration of cell migration for wound repair. We hypothesized that a bidirectional mechanism involving PKA and PKC regulates epithelial airway inflammatory responses. To test this hypothesis, primary human bronchial epithelial cells and BEAS-2B cells were treated with hog dust extract (HDE) in the presence or absence of cAMP. PKC-ε activity was significantly reduced in cells that were pretreated for 1 h with 8-bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP) before exposure to HDE (P < 0.05). HDE-induced IL-6, and IL-8 release was significantly lower in cells that were pretreated with 8-Br-cAMP (P < 0.05). To exclude exchange protein activated by cAMP (EPAC) involvement, cells were pretreated with either 8-Br-cAMP or 8-(4-chlorophenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate (8-CPT-2Me-cAMP) (EPAC agonist). 8-CPT-2Me-cAMP did not activate PKA and did not reduce HDE-stimulated IL-6 release. In contrast, 8-Br-cAMP decreased HDE-stimulated tumor necrosis factor (TNF)-α-converting enzyme (TACE; ADAM-17) activity and subsequent TNF-α release (P < 0.001). 8-Br-cAMP also blocked HDE-stimulated IL-6 and keratinocyte-derived chemokine release in precision-cut mouse lung slices (P < 0.05). These data show bidirectional regulation of PKC-ε via a PKA-mediated inhibition of TACE activity resulting in reduced PKC-ε-mediated release of IL-6 and IL-8.

Influence of farming exposure on the development of asthma and asthma-like symptoms.

Based upon age and type of farming exposures, a wide range of studies demonstrate either protective or deleterious effects of the farming environment on asthma. In this review, we highlight key studies supporting the concept that farming exposure protects children from asthma and atopy based on studies performed largely in European pediatric cohorts. Various types of farming in certain regions appear to have a greater effect on asthma protection, as does the consumption of unpasteurized milk. In the United State, where concentrated animal feeding operations (CAFOs) are more common, asthma is increased in children exposed especially to swine CAFOs; whereas, rates of atopy and allergy are lower in these children. We also review studies evaluating the role of farming exposures both as a child and/or as an adult on asthma seen in adults. The importance of microbes in farming environments and the contribution of various components of the innate immune system including toll-like receptors to the underlying mechanisms of asthma related to farming exposures are also reviewed.

Modeled Effectiveness of Ventilation with Contaminant Control Devices on Indoor Air Quality in a Swine Farrowing Facility

Because adverse health effects experienced by swine farm workers in concentrated animal feeding operations (CAFOs) have been associated with exposure to dust and gases, efforts to reduce exposures are warranted, particularly in winter seasons when exposures increase due to decreased ventilation. Simulation of air quality and operating costs for ventilating swine CAFO, including treating and recirculating air through a farrowing room, was performed using mass and energy balance equations over a 90-day winter season. System operation required controlling heater operation to achieve room temperatures optimal to ensure animal health (20 to 22.5°C). Five air pollution control devices, four room ventilation rates, and five recirculation patterns were examined. Inhalable dust concentrations were easily reduced using standard industrial air pollution control devices, including a cyclone, filtration, and electrostatic precipitator. Operating ventilation systems at 0.94 m3 s−1 (2000 cfm) with 75 to 100% recirculation of treated air from cyclone, electrostatic precipitator, and shaker dust filtration system achieves adequate particle control with operating costs under $1.00 per pig produced ($0.22 to 0.54), although carbon dioxide (CO2) concentrations approach 2000 ppm using in-room ventilated gas fired heaters. In no simulation were CO2 concentrations below industry recommended concentrations (1540 ppm), but alternative heating devices could reduce CO2 to acceptable concentrations. While this investigation does not represent all production swine farrowing barns, which differ in characteristics including room dimensions and swine occupancy, the simulation model and ventilation optimization methods can be applied to other production sites. This work shows that ventilation may be a cost-effective control option in the swine industry to reduce exposures.[Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: detailed simulation results, including room concentration and operation cost for all simulations performed in this study.]