Hedgehog signaling is required for larval muscle development and larval metamorphosis of the mussel Mytilus coruscus.

Understanding the developmental processes and signaling pathways involved in larval myogenesis and metamorphosis is crucial for comprehending the life history and adaptive strategies of marine organisms. In this study, we investigated the temporal and spatial patterns of myogenesis in the mussel Mytilus coruscus (Mc), focusing on the emergence and transformation of major muscle groups during different larval stages. We also explored the role of the Hedgehog (Hh) signaling pathway in regulating myogenesis and larval metamorphosis. The results revealed distinct developmental stages characterized by the emergence of specific muscular components, such as velum retractor muscles and anterior adductor muscles, in D-veliger and umbo larvae, which are responsible for the planktonic stage. In the pediveliger stage, posterior ventral, posterior adductor, and foot muscles appeared. After larval metamorphosis, the velum structure and its corresponding retractor muscles degenerate, indicating the transition from planktonic to benthic life. We observed a conserved pattern of larval musculature development and revealed a high degree of conservation across bivalve species, with comparable emergence times during myogenesis. Furthermore, exposure to the Hh signaling inhibitor cyclopamine impaired larval muscle development, reduced larval swimming activity, and inhibited larval metamorphosis in M. coruscus. Cyclopamine-mediated inhibition of Hh signaling led to reduced expression of four key genes within the Hh signaling pathway (McHh, McPtc, McSmo, and McGli) and the striated myosin heavy chain gene (McMHC). It is hypothesised that the abnormal larval muscle development in cyclopamine-treated groups may be an indirect effect due to disrupted McMHC expression. We provide evidence for the first time that cyclopamine treatment inhibited larval metamorphosis in bivalves, highlighting the potential involvement of Hh signaling in mediating larval muscle development and metamorphosis in M. coruscus. The present study provides insights into the dynamic nature of myogenesis and the regulatory role of the Hh signaling pathway during larval development and metamorphosis in M. coruscus. The results obtained in this study contribute to a better understanding of the evolutionary significance of Hh signaling in bivalves and shed light on the mechanisms underlying larval muscle development and metamorphosis in marine invertebrates.

Hyposalinity stress reduces mussel byssus secretion but does not cause detachment.

Environmental stressors such as salinity fluctuations can significantly impact the ecological dynamics of mussel beds. The present study evaluated the influence of hyposalinity stress on the detachment and survival of attached mussels by simulating a mussel farming model in a laboratory setting. Byssus production and mechanical properties of thread in response to varying salinity levels were assessed, and histological sections of the mussel foot were analyzed to identify the changes in the byssus secretory gland area. The results showed that hyposalinity stress (20 and 15 psu) led to a significant decrease in mussel byssus secretion, delayed initiation of new byssus production, and reduced plaque adhesion strength and breaking force of byssal threads compared to the control (30 psu) (p < 0.05). The complete suppression of byssal thread secretion in mussels under salinity conditions of 10 and 5 psu, leading to lethality, indicates the presence of a blockade in byssus secretion when mussels are subjected to significant physiological stressors. Histological analysis further demonstrated a decrease in the percentage of foot secretory gland areas in mussels exposed to low salinities. However, contrary to expectations, the study found that mussels did not exhibit marked detachment from ropes in response to the reduced salinity levels during one week of exposure. Hyposalinity stress exposure reduced the byssal secretion capacity and the mechanical properties of threads, which could be a cause for the detachment of suspension-cultured mussels. These results highlight the vulnerability of mussels to hyposalinity stress, which significantly affects their byssus mechanical performance.

The influence of using different types of modified vermiculite cover on ammonia mitigation from animal slurry storage: The role of sulfuric acid.

Animal slurry storage is an important ammonia (NH3) emission source. Sulfuric acid (H2SO4)-modified vermiculite coverage is a new promising technology for controlling NH3 emission from slurry storage. However, the underlying mechanisms in controlling the mitigation effect remain unclear. Here, a series of experiments to determine the effect of H2SO4 on the modified vermiculite properties, floating persistence, and NH3 mitigation effect was conducted. Results showed that abundant H2SO4 and sulfate remained on the outer surface and in the extended inner pores of the vermiculite with acidifying H+ concentrations higher than 5 M. An initial strong instantaneous acidification of surface slurry released rich carbon dioxide bubbles, strengthening cover floating performance. An acidification in the vermiculite cover layer and a good coverage inhibition interacted, being the two leading mechanisms for mitigating NH3 during initial 40-50 days of storage. The bacterial-amoA gene dominated the conversion of NH3 to nitrous oxide after 50 days of storage. Vermiculite with 5 M H+ modification reduced the NH3 emissions by 90 % within the first month of slurry storage and achieved a 64 % mitigation efficiency throughout the 84 days period. With the development of the aerial spraying equipment such as agricultural drones, acidifying vermiculite coverage hold promise as an effective method for reducing NH3 emission while absorbing nutrients from liquid slurry storage tank or lagoon. This design should now be tested under field conditions.

Hydrogen production promotion and energy saving in anaerobic co-fermentation of heat-treated sludge and food waste.

The objective of this paper is to gain insights into the synergistic advantage of anaerobic co-fermentation of heat-treated sludge (HS) with food waste (FW) and heat-treated food waste (HFW) for hydrogen production. The results showed that, compared with raw sludge (RS) mixed with FW (RS-FW), the co-substrate of HS mixed with either FW (HS-FW) or HFW (HS-HFW) effectively promoted hydrogen production, with HS-HFW promoted more than HS-FW. The maximum specific hydrogen production (MSHP) and the maximum hydrogen concentration (MHC) of HS-HFW were 40.53 mL H2/g dry weight and 57.22%, respectively, and 1.21- and 1.45-fold as high as those from HS-FW. The corresponding fermentation was ethanol type for HS-HFW and butyric acid type for HS-FW. The net energy production from RS-FW and HS-FW was both negative, but it was positive (2.57 MJ) from 40% HFW addition to HS-HFW. Anaerobic fermentation was more viable for HS-HFW.

Ioxynil and diethylstilbestrol impair cardiac performance and shell growth in the mussel Mytilus coruscus.

The herbicide ioxynil (IOX) and the synthetic estrogen diethylstilbestrol (DES) are environmentally relevant contaminants that act as endocrine disruptors (EDCs) and have recently been shown to be cardiovascular disruptors in vertebrates. Mussels, Mytilus coruscus, were exposed to low doses of IOX (0.37, 0.037 and 0.0037 mg/L) and DES (0.27, 0.027 and 0.0027 mg/L) via the water and the effect monitored by generating whole animal transcriptomes and measuring cardiac performance and shell growth. One day after IOX (0.37 and 0.037 mg/L) and DES (0.27 and 0.027 mg/L) exposure heart rate frequency was decreased in both groups and 0.27 mg/L DES significantly reduced heart rate frequency with increasing time of exposure (P < 0.05) and no acclimatization occurred. The functional effects were coupled to significant differential expression of genes of the serotonergic synapse pathway and cardiac-related genes at 0.027 mg/L DES, which suggests that impaired heart function may be due to interference with neuroendocrine regulation and direct cardiac effect genes. Multiple genes related to detoxifying xenobiotic substances were up regulated and genes related to immune function were down regulated in the DES group (vs. control), indicating that detoxification processes were enhanced, and the immune response was depressed. In contrast, IOX had a minor disrupting effect at a molecular level. Of note was a significant suppression (P < 0.05) by DES of shell growth in juveniles and lower doses (< 0.0027 mg/L) had a more severe effect. The shell growth depression in 0.0027 mg/L DES-treated juveniles was not accompanied by abundant differential gene expression, suggesting that the effect of 0.0027 mg/L DES on shell growth may be direct. The results obtained in the present study reveal for the first time that IOX and DES may act as neuroendocrine disrupters with a broad spectrum of effects on cardiac performance and shell growth, and that DES exposure had a much more pronounced effect than IOX in a marine bivalve.

Identified factors and predicted unidentified-factors affecting ammonia emissions from a swine building.

Large variabilities in ammonia (NH3) released from animal manure and emitted from different livestock buildings were frequently reported, but the factors influencing the emissions were not sufficiently investigated. In this paper, continuously monitored data of NH3 emissions and other relevant environmental variables under controlled conditions in a 12-room experimental swine building for a 155-d complete wean-to-finish cycle were studied. Measurement data mining was conducted at both spatial and temporal dimensions using panel data analysis with heterogeneous time trends. The pig diet, total pig weight, and the pit air temperature were identified as the major influencing factors for the variabilities by using multivariate linear regression. Two unidentified factors that imposed substantial influences on the NH3 emission variabilities were predicted. They were most possibly related to variations in microenvironment and microbial activity inside the manure in the pit. The results suggest necessary future research to identify physical properties of the new NH3 emissions factors in microbiological and biochemical processes.

Computational Fluid Dynamics Modeling of a Broiler House Microclimate in Summer and Winter.

Appropriate microclimate conditions in broiler housing are critical for optimizing poultry production and ensuring the health and welfare of the birds. In this study, spatial variabilities of the microclimate in summer and winter seasons in a mechanically ventilated broiler house were modeled using the computational fluid dynamics (CFD) technique. Field measurements of temperature, relative humidity, and airspeeds were conducted in the house to compare the simulated results. The study identified two problems of high temperature in summer, which could result in bird heat stress and stagnant zones in winter, and simulated possible alternative solutions. In summer, if an evaporative cooling pad system was used, a decrease in temperature of approximately 3 °C could be achieved when the mean air temperature rose above 25 °C in the house. In winter, adding four 500-mm circulation fans of 20-m spacing inside the house could eliminate the accumulation of hot and humid air in the stagnant zones in the house. This study demonstrated that CFD is a valuable tool for adequate heating, ventilation, and air conditioning system design in poultry buildings.

The effect of reduced CP, synthetic amino acid supplemented diets on growth performance and nutrient excretion in wean to Finish swine.

Mixed sex pigs (n = 720) were placed in 12 rooms (Purdue Swine Environmental Research Building) to measure the effect of reduced crude protein (CP), amino acid (AA)-supplemented diets on growth and the carcass. Pigs were blocked by body weight (BW) and gender and allotted to room and pen (10 mixed-sex pigs/pen). Pigs were fed a nine-phase, wean-finish program. Control pigs consumed corn-soybean meal-distiller's dried grains with solubles (DDGS) diets containing no to minimal (Met) synthetic AA. The 2X diet was formulated to meet the seventh most-limiting AA, and balanced using synthetic AAs to meet all AA needs. The 1X diet was formulated to meet a CP value halfway between the control and 2X diet, and also balanced using synthetic AAs to meet all AA needs. Diets were formulated to identical net energy concentrations and balanced to meet standard ileal digestible NRC 2012 AA requirements. Pit vacuum samples were collected at the end of each growth phase for analyses of nitrogen, C and dry matter (DM). Pigs fed the Control and 1X diet grew faster (P < 0.005), had greater gain:feed (P < 0.001), and were heavier at market (P < 0.001) than animals fed the 2X diet. No consistent effects of diet were observed on average daily feed intake. Carcass data were analyzed for sex, diet and sex*diet effects. Reductions in dietary CP resulted in a linear reduction in ammonium nitrogen excretion per kg of BW gain in Nursery (P < 0.001) and Grow-Finish (P < 0.001) phases. Reductions in dietary CP, with synthetic AA supplementation resulted in a linear reduction in total nitrogen excreted per kg BW gain in the Grow-Finish phase (P < 0.001) and overall (P < 0.001). Total mineral excretion per kg gain was reduced in pigs fed 1X and 2X diets compared with control-fed pigs (P < 0.005). Reductions in dietary CP of ~3 and 5%-units from wean-finish result in reductions of total N excretion of 11.7 and 24.4%, respectively. Reduced performance and carcass characteristics observed in pigs fed the 2X diets indicates an inaccurate estimate of NRC 2012 AA requirements or ratios to lysine in a low CP diet.

Antidiabetic potential of Catechu via assays for α-glucosidase, α-amylase, and glucose uptake in adipocytes.

ETHNOPHARMACOLOGICAL RELEVANCE: Catechu is the dry water extract of barked branches or stems from Senegalia catechu(L. F.)P. J. H. Hurter & Mabb, which is used as a hypoglycemic regulator in recent researches. Potential anti-hyperglycemic components and the putative mechanisms were evaluated in this investigation. AIM OF THE STUDY: Evaluated the hypoglycemic activity of Catechu via α-glucosidase, α-amylase inhibition assays, and glucose uptake in 3T3-L1 adipocytes. MATERIALS AND METHODS: The effects of Catechu on α-glucosidase, α-amylase inhibition assays and glucose uptake experiment were tested after the ethanol extract of Catechu (EE) was sequentially partitioned with petroleum ether (PEE), ethyl acetate (EAE), and n-butanol fractions (NBE). Next, HPLC-MS and traditional Chinese medicine (TCM) database were used to detect and analyze the primary active ingredients presented in hypoglycemic fraction. In addition, in silico molecular docking study was used to evaluate the candidates' inhibitory activity against α-glucosidase and α-amylase. RESULTS: The results of α-glucosidase and α-amylase inhibition assays indicated that all fractions, with the exception of PEE, presented significant inhibitory effects on α-glucosidase and α-amylase. The inhibitory effect of NBE on α-glucosidase was similar to the positive control (NBE IC50 = 0.3353 ± 0.1215 µg/mL; Acarbose IC50 = 0.1123 ± 0.0023 µg/mL). Furthermore, the inhibitory kinetics of α-glucosidase revealed that all fractions except for PEE belong to uncompetitive type. In silico molecular docking analysis showed that the main compositions of NBE ((-)-epicatechin, cyanidin, and delphinidin) possessed superior binding capacities with α-glucosidase (3WY1 AutoDock score: 4.82 kcal/mol; -5.59 kcal/mol; -5.63 kcal/mol) and α-amylase (4GQR AutoDock score: 4.80 kcal/mol; -5.89 kcal/mol; -4.26 kcal/mol), respectively. The results of glucose uptake experiment indicated that EE, PEE, EAE, and NBE without significant promotion effect on glucose uptake rate of 3T3-L1 adipocytes (P > 0.05). CONCLUSION: This study revealed that the hypoglycemic effect of Catechu might be related to the inhibitory effects of phenols on digestive enzymes (α-glucosidase and α-amylase), and the possible active phenols were (-)-epicatechin, cyanidin, delphinidin and their derivatives, which provided scientific evidences for Catechu's traditional use to treat T2DM.

Summary of Known U.S. Injuries and Fatalities Involving Livestock Waste Storage, Handling, and Transport Operations: 1975-2019.

HIGHLIGHTS: Approximately ten cases were documented annually over the 44-year period; 48% were in the last decade and 28% were in the last three years, primarily due to more aggressive surveillance and on-line access to incident reports. A total of 389 incidents involving 459 individuals were documented, of which 59% were fatal; >85% of the victims were male, with an average age of 37. 49 rescue incidents involved a total of 119 secondary victims, indicating that approximately 26% of the victims were secondary victims, including first responders. 20% of all victims, when age was known, were children or youth under the age of 21. ABSTRACT: There is limited published research exploring the frequency and causes of livestock waste-related fatalities and injuries among farm operators and workers. While there has been ongoing surveillance of mortality and morbidity involving agricultural confined space-related incidents, such as grain storage facilities, few resources have been invested in estimating the frequency of livestock waste-related incidents, which are often reported as primarily involving confined spaces. Existing surveillance efforts have historically underreported fatal cases, injuries, and near misses and misclassified these incidents as non-farm related. For nearly 40 years, the Purdue Agricultural Confined Spaces Incident Database (PACSID) has been used to document agricultural confined space-related incidents, of which manure storage and handling activities have accounted for 22% of the cases documented. The specific goal of this study was to address the gap in the current understanding of the frequency and severity of injuries associated with livestock waste storage, handling, and transport by: (1) developing a consistent way to identify, document, and code these cases; (2) summarizing all known U.S. cases, both fatal and non-fatal, currently documented in the PACSID; (3) identifying the most significant risks contributing to livestock waste storage, handling, and transport-related incidents; and (4) providing evidence-based recommendations and mitigation strategies to enhance the effectiveness of current injury prevention measures. The PACSID and other sources were mined for relevant data, and an aggressive effort was made to document additional cases through a variety of surveillance methods. A total of 459 individual U.S. cases from the study period (1975 to 2019) were identified, coded using a uniform coding system, and summarized. Overall, cases were documented in 43 states, with 66% (302 cases) documented in heavily agricultural and, more specifically, historically strong dairy production states. Of the cases reviewed, 59% were fatal, males ages 21 to 30 and dairy farm workers were identified as high-risk populations, 20% were identified as under the age of 21, and 49 incidents involved multiple victims. Farm injury data limitations and underreporting were problematic, especially during the early years of the study period. However, the findings provide a foundation for recommending safer workplace safety and health practices, evaluating existing engineering and regulatory standards, assessing the impacts of current injury prevention efforts, and redesigning farm safety programs, especially those targeting livestock workers, to reduce the frequency and severity of these incidents.

Long-term performance of three mesophilic anaerobic digesters to convert animal and agro-industrial wastes into organic fertilizer.

Few studies have investigated the performance of anaerobic digestion (AD) to convert animal and agro-industrial wastes to organic fertilizers over a long-term field conditions. This paper studied three large-scale mesophilic digesters (D1eD3) over two years for their effects on feedstocks, which were dairy manure for D1 and D2 and co-digestion mixed manure and agro-industrial wastes for D3. Hydraulic retention times (HRT) were 9 d for D1, 12 d for D2, and 34 d for D3. Digester influent and effluent samples were taken every two months from the digesters and analyzed for pH, and concentrations of total solids (TS), ammonium nitrogen (NH4-N), total Kjeldahl nitrogen (TKN), total phosphorus (TP), and eight metals. The study revealed high variability in converting feedstock in the three digesters. Compared with their respective influent, the mean digester effluent pH decreased from 7.9 by 0.6 in D1 (p < 0.01) and by 0.3 in D2 (p < 0.01), but it increased from 6.1 by 1.8 in D3 (p < 0.01). The mean digester effluent TS increased from 3.4% by 0.1% (p > 0.05) in D1, but it decreased from 4.9% by 1.3% in D2 (p < 0.05) and from 12.3% by 4.8% in D3 (p < 0.01). All three digesters significantly increased NH4-N concentrations by 21.4 e81.8% (p < 0.05), but insignificantly changed TKN and TP concentrations (p > 0.05). Effects of AD on all metal concentrations were mixed and were insignificant (p > 0.05) because of large concentration variations. However, study of a ratio quotient (q Mg ) using magnesium (Mg) as the reference discovered accumulation of NH4-N, copper, potassium, and sodium, but loss of TKN, TP, iron, manganese, zinc, and calcium during AD for D2 and D3. The impact of AD conversion was closely related with types of feedstock (on pH) and HRT (on TS and NH4-N). The results of this study can assist in developing strategies for cleaner production using AD in an environmentally sustainable manner.

A synchronous demodulation technology based on sample-and-hold for eddy current sensors.

This paper proposes a synchronous demodulation technology based on sample-and-hold which shows significant advantages in the application of precision sensors. The traditional synchronous demodulation methods are discussed, and then the working principle of the proposed method is theoretically analyzed in detail. It is found that the proposed method can not only effectively suppress the harmonic components caused by the signal source but is also beneficial to improving the dynamic range of precision sensors. The eddy current sensor is adopted as an example of precision sensors, and a high-precision eddy current displacement sensor prototype was designed and tested. The results show that with the proposed method, the harmonics in the output signal are suppressed more effectively, and the demodulation circuit is relatively simplified. This synchronous demodulation method has an extensive application prospect in precision sensors.

Summary of Injuries and Fatalities Involving Livestock Manure Storage, Handling, and Transport Operations in Seven Central States: 1976-2019.

HIGHLIGHTS A total of 133 cases were documented in a seven-state region, with Iowa reporting 43% of the cases and asphyxiations accounting for 42% of all cases. Most victims were male (>79%) with an average age of 38 years. The overall fatality rate was 57%, and 16% of the victims were under the age of 21. Thirteen incidents involved secondary victims, including eleven incidents involving two, one incident involving three, and one incident involving four. ABSTRACT. Research was conducted to document, classify, analyze, and summarize available injury and fatality data involving facilities and equipment for livestock manure storage, handling, and transport in the seven-state region (Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, and South Dakota) served by the Central States Center for Agricultural Safety and Health (CS-CASH). Data were initially drawn from the Purdue Agricultural Confined Space Incident Database (PACSID), which contained over 2,400 individual U.S. cases of agricultural confined space related entrapment, engulfment, entanglement, asphyxiation, and falls that were documented between 1975 and 2019. Data from these cases have been partially summarized and published, but the findings did not include in-depth analysis of manure-related incidents. Approximately one in five (460) of the 2,400+ cases that were documented over 44 years involved storage, handling, or transport of livestock wastes, including exposure to toxic gases. Of these, 133 cases were documented as having occurred in the targeted seven-state region. Each case was identified and coded according to a protocol developed previously to classify incidents related to livestock manure handling, storage, and transport. Iowa and Minnesota accounted for 79% of the total, with swine operations accounting for 33% of cases when livestock type was known. Of the victims, 79% were male. Ages ranged from 1 to 85, with an average age of 38, and 15% of the victims were age 21 and under. There were 13 incidents for which two or more victims were identified, including one incident involving four victims. It is believed that historical under-reporting of incidents, especially non-fatal incidents, continues to be a barrier to achieving a more comprehensive understanding of the scope and magnitude of the problem. However, the findings are sufficient to be used in cooperation with stakeholders to enhance the content and delivery of evidence-based agricultural safety and health programs, promote safer work practices, and contribute to the development of engineering design standards. The desired outcomes of this research include more effective strategies to protect farmers and farm workers who are at high risk of manure-related injuries. The findings also provide a sufficient baseline to gauge the effectiveness of future injury prevention measures.

Early Use of Corticosteroid May Prolong SARS-CoV-2 Shedding in Non-Intensive Care Unit Patients with COVID-19 Pneumonia: A Multicenter, Single-Blind, Randomized Control Trial.

BACKGROUND: There is still no clinical evidence available to support or to oppose corticosteroid treatment for coronavirus disease 2019 (COVID-19) pneumonia. OBJECTIVE: To investigate the efficacy and safety of corticosteroid given to the hospitalized patients with COVID-19 pneumonia. METHODS: This was a prospective, multicenter, single-blind, randomized control trial. Adult patients with COVID-19 pneumonia who were admitted to the general ward were randomly assigned to either receive methylprednisolone or not for 7 days. The primary end point was the incidence of clinical deterioration 14 days after randomization. RESULTS: We terminated this trial early because the number of patients with COVID-19 pneumonia in all the centers decreased in late March. Finally, a total of 86 COVID-19 patients underwent randomization. There was no difference of the incidence of clinical deterioration between the methylprednisolone group and control group (4.8 vs. 4.8%, p = 1.000). The duration of throat viral RNA detectability in the methylprednisolone group was 11 days (interquartile range, 6-16 days), which was significantly longer than that in the control group (8 days [2-12 days], p = 0.030). There were no significant differences between the 2 groups in other secondary outcomes. Mass cytometry discovered CD3+ T cells, CD8+ T cells, and NK cells in the methylprednisolone group which were significantly lower than those in the control group after randomization (p < 0.05). CONCLUSIONS: From this prematurely closed trial, we found that the short-term early use of corticosteroid could suppress the immune cells, which may prolong severe acute respiratory syndrome coronavirus 2 shedding in patients with COVID-19 pneumonia. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04273321.

A critical review of advancement in scientific research on food animal welfare-related air pollution.

Air pollution generates hazardous pollutants that have resulted in safety, health, and other welfare issues of food animals. This paper reviewed scientific research advancement in food animal welfare-related air pollution based on 219 first-hand research publications in refereed journals (referred to as "RPs") over the past nine decades. Scientific studies in this area began in the 1930s. The number of RPs has increased significantly with each decade from the 1960s to the 1980s, then decreased until the 2010s. Twenty-six countries have contributed to this multidisciplinary research. About 52% of the studies were conducted in the U.S. and U.K. Research activities have surged in China since the 2010s. On-farm discoveries in air toxicity that resulted in animal death or injury were all from observational studies. About 75% of the studies were experimental and conducted primarily under laboratory conditions. Ammonia (NH3) was the main pollutant in 59% of the RPs, followed by dust, hydrogen sulfide (H2S), bacteria and endotoxins, carbon dioxide (CO2), carbon monoxide (CO), silo gas, sulfur dioxide (SO2), and odor. Approximately 23% of RPs reported multiple pollutants in the same study. The most intensively studied animal species were poultry (broilers, hens, turkeys, ducks, and eggs and embryos in 44% of the RPs) and pigs (also 44%), followed by cattle, and sheep and goats. Scientific investigations in this area were driven by the research focuses in the areas of animal agriculture and industrial air pollution. Some major research teams played important roles in advancing scientific research. However, research in this area is still relatively limited. There is a great need to overcome some technical challenges and reverse the trend of decreasing research activities in North America and Europe.

Farm-Related Injuries and Fatalities Involving Children, Youth, and Young Workers during Manure Storage, Handling, and Transport.

Objective: Manure storage, handling, and transport facilities and equipment have been associated with life threatening hazards on many livestock farms. These hazards have been documented in prior research as including 1) exposure to toxic manure gases or lack of adequate oxygen in enclosed structures, which can be fatal to both humans and livestock; 2) below and above ground liquid manure storage structures that have the potential risk for drowning and falling; and 3) mechanical hazards associated with manure handling and transport equipment, including entanglement, road collisions, runover, and equipment failure.Methods: Over the past 40 years, Purdue University's Agricultural Safety and Health Program (PUASHP) has collected, documented, and maintained data regarding agricultural-related injuries and fatalities associated with agricultural confined spaces in the United States. As part of ongoing surveillance, a total of 369 fatal and non-fatal cases relating to manure storage, handling and transport equipment, and facilities have been documented. Of these, 89 have involved children, youth, and young farm workers ages (birth-21) documented between 1975 and 2019. The purpose of this study was to summarize these 89 documented cases to better understand contributing factors and to develop recommendations for evidence-based strategies to reduce the frequency and severity of these incidents. Though recognized as not comprehensive for all incidents of this type, the data represent the largest data set known to exist, providing insight into previously unstudied hazards facing children and youth living and working on, and visiting farms as non-workers.Results: Findings in this study include: there has been an increase in the documented frequency of these incidents, which may be due, at least partially, to enhanced or more aggressive surveillance efforts; 57% of the cases were fatal; incidents involving underground or inground manure storage facilities were the most frequent type; incidents involving manure transport vehicles were higher than expected; 33% of the victims were five years of age and younger; and July was the month with the most documented incidents.Conclusions: Recommendations for future injury prevention strategies include incorporation of information on manure-related hazards in curricula targeting children and youth, more aggressive enforcement of child labor laws that currently prohibit the employment of youth to work in manure storage structures or to be involved in their operations, and greater use of physical and administrative controls, including safety signage, fencing, gates, and covers to restrict access to manure storage structures.

Dynamic and 3-D spatial variations in manure characteristics in two commercial manure-belt laying hen houses.

Animal manure could be hazardous to human and animals if not managed properly. Laying hen manure in two commercial manure-belt houses was sampled in seven events over two years. A total of 124 samples was taken in randomly-selected 3-D space with 24 subspaces, composed of 3 sections × 4 sides × 2 floors in the houses. The samples were analyzed for manure pH, total solids (TS), and total ammonia (NH3). Manure characteristics demonstrated large temporal variations that were correlated with indoor temperature and ventilation rate and demonstrated quasi seasonal patterns. Variations in manure NH3 were larger than TS and pH. Manure characteristics varied substantially in the 3-D space but no patterns could be seen among the four sides and between the two floors. However, manure with different ages in the 3 sections along the manure belt moving direction showed differences in manure TS and NH3. Manure on the belts could loss approximately 2.5 % moisture and 0.2 % NH3 concentration per day.

New insights into concentrations, sources and transformations of NH3, NOx, SO2 and PM at a commercial manure-belt layer house.

Pollutant gases and particulate matters (PM) from livestock facilities can affect the health of animals and farm workers and lead to great social environmental risks. This paper presents a comprehensive study on the characteristics of ammonia (NH3), nitrogen oxides (NOx), sulfur dioxide (SO2) and PM (including PM2.5 and PM10) in a 100,000-bird manure-belt layer house in suburb Beijing for three typical seasons of summer, autumn and winter. Indoor air was sampled at an exhaust fan of the mechanically ventilated commercial house. The monitored indoor concentrations of NH3, NOx, SO2, PM2.5 and PM10 were 3.7-5.0 mg m-3, 17-58 µg m-3, 0-11 µg m-3, 100-149 µg m-3 and 354-828 µg m-3, respectively. The indoor NH3 concentrations were largely influenced by the manure removal frequency. The NOx and SO2 were mainly sourced from the ambient air, and the NOx was also partly sourced from manure decomposition in summer. The indoor PM2.5 and PM10 were largely sourced from the ambient air and the indoor manure, respectively. The abundant indoor NH3 caused significantly higher NH4+ concentration in the indoor PM10 (7.98 ± 9.04 µg m-3) than that in the ambient PM10 (3.48 ± 3.52 µg m-3). Secondary inorganic ions (SO42-, NO3- and NH4+) totally contributed 5.7% and 14.6% to the indoor and ambient PM2.5, respectively; they contributed 2.8% and 8.9% to the indoor and ambient PM10, respectively. Organic carbon was the main component of the PM and accounted for 26.6% and 41.5% of the indoor PM2.5 and PM10, respectively. Heavy metal elements (Zn, Cu and Cr) were likely transported from feed to manure and finally accumulated in the PM. Given the high emission potential, the air pollutants from animal production suggested potential risks for human health.

Effects of antibiotic-free pig rearing on ammonia emissions from five pairs of swine rooms in a wean-to-finish experiment.

Antibiotic use and ammonia (NH3) emissions during animal production are two environmental issues of worldwide concern. However, the role of antibiotics on NH3 emissions is still unknown. This study evaluated the effects of rearing pigs without antibiotics on NH3 emissions from a swine experimental building starting with 657 piglets during a wean-to-finish production cycle of 154 days. Pigs were reared in two groups of 10 rooms that were divided into five 2-room pairs (P1-P5) and fed in nine dietary phases. Each pair consisted of one room without antibiotics (no antibiotics in the diet, water, or injectable) and another room as a positive control. Control animals were fed diets containing carbadox-10 (phases 1-4), chlortetracycline (CTC, phase 5), lincomix (phases 6-7), and tylan 40 (phases 8-9). Temperatures in the pig living space and the under-floor manure pit headspace were continuously measured. Ventilation rates at all wall fans and pit fans were obtained by continuous monitoring. Ammonia concentrations in the wall and pit fan exhaust air, and in room inlet air were measured with two multi-gas monitors. Only days that contained at least 18 h of data each day were validated and used. The study generated 1337 room-days of valid data of NH3 emission rates, with a data completeness of 88.6%. Daily mean NH3 emission patterns demonstrated large variations between the paired rooms and among different pairs. Within the individual 2-room pairs, no NH3 emission differences were found in P1 (rooms 1 and 2, p = 0.34) and P2 (rooms 3 and 4, p = 0.44). Significant differences were found in P3-P5 (p < 0.01). The antibiotic-free rooms emitted more NH3 from P3 and P4, but less NH3 from P5. However, the combined cycle mean NH3 emissions from the group of five antibiotic-free rooms and the group of five control rooms were 41.6 ±â€¯10.5 and 39.4 ±â€¯10.6 g d-1 AU-1 (mean ±â€¯standard deviation. AU = 500 kg live body weight), respectively. Therefore, there was no statistical difference in combined cycle mean NH3 emissions from rearing pigs with or without antibiotics (p = 0.78). This study also revealed that experiments with multiple replicates and long NH3 monitoring durations were necessary to avoid potential misinterpretation of experimental results.