Comparison of ammonia emissions related to nitrogen use efficiency of livestock production in Europe

Reducing dietary protein and supplementation with starch or rumen-protected methionine and its effect on performance and nitrogen efficiency in dairy cows fed a red clover and grass silage-based diet

The increasing cost of milk production, in association with tighter manure N application regulations and challenges associated with ammonia emissions in many countries, has increased interest in feeding lower crude protein (CP) diets based on legume silages. Most studies have focused on alfalfa silage, and little information is available on low-CP diets based on red clover silage. Our objectives were to examine the effects of dietary CP content and supplementing a low-CP diet with dietary starch or rumen-protected Met (RPMet) on the performance, metabolism, and nitrogen use efficiency (NUE; milk N output/N intake) in dairy cows fed a red clover and grass silage-based diet. A total of 56 Holstein-Friesian dairy cows were blocked and randomly allocated to 1 of 4 diets over a 14-wk feeding period. Diets were based on red clover and grass silages at a ratio of 50:50 on a dry matter (DM) basis and were fed as a total mixed ration, with a 53:47 ratio of forage to concentrate (DM basis). The diets were formulated to supply a similar metabolizable protein (MP) content, and had a CP concentration of either 175 g/kg DM (control [CON]) or 150 g/kg DM (low-protein [LP]), or LP supplemented with either additional barley as a source of starch (LPSt; +64 g/kg DM) or RPMet (LPM; +0.3 g/100 g MP). At the end of the 14-wk feeding period, 20 cows (5 per treatment) continued to be fed the same diets for a further 6 d, and total urine output and fecal samples were collected. We observed that dietary treatment did not affect DM intake, with a mean of 21.5 kg/d; however, we also observed an interaction between diet and week with intake being highest in cows fed LPSt in wk 4 and CON in wk 9 and 14. Mean milk yield, 4% fat-corrected milk, and energy-corrected milk were not altered by treatment. Similarly, we found no effect of dietary treatment on milk fat, protein, or lactose content. In contrast, milk and plasma urea concentrations were highest in cows fed CON. The concentration of blood plasma β-hydroxybutyrate was highest in cows receiving LPM and lowest in LPSt. Apparent NUE was 28.6% in cows fed CON and was higher in cows fed any of the low-protein diets (LP, LPSt, or LPM), with a mean value of 34.2%. The sum of milk fatty acids with a chain length below C16:0 was also highest in cows fed CON. We observed that dietary treatment did not affect the apparent whole-tract nutrient digestibility of organic matter, N, neutral detergent fiber, and acid detergent fiber, with mean values of 0.785, 0.659, 0.660, and 0.651 kg/kg respectively, but urinary N excretion was approximately 60 g/d lower in cows fed the low-CP diets compared with CON. We conclude that reducing the CP content of red clover and grass silage-based diets from 175 to 150 g/kg DM while maintaining MP supply did not affect performance, but reduced the urinary N excretion and improved NUE, and that supplementing additional starch or RPMet had little further effect.

Decoupling livestock and poultry pollution emissions from industrial development: A step towards reducing environmental emissions

China has implemented policies like Leading areas for Agricultural Green Development (LAGD) to mitigate livestock and poultry farming pollution while promoting industry growth. However, it remains uncertain whether LAGDs have successfully balanced emission reduction with stable development. This study examines 165 LAGDs to analyze changes in emissions, assess the decoupling of emission reduction from output value, and identify influencing factors. Findings reveal that emissions from livestock and poultry in LAGDs initially increased and then decreased between 2010 and 2019. Cattle were responsible for over 40% of fecal emissions, and pigs for more than 20%. Additionally, pigs contributed to over 61% of urine emissions. From 2010 to 2014, increases in chemical oxygen demand were mainly due to pigs and cattle. Total nitrogen levels were significantly impacted by cattle, while pigs were affected by total phosphorus. From 2014 to 2019, reductions in emissions were largely attributed to a decrease in pig-related pollutants. The decoupling status shifted from strong to weak and then back to strong between 2014 and 2019. Production efficiency played a crucial role in reducing emissions, while changes in industrial structure moved from supporting to hindering this reduction. Economic development was a primary factor in driving these changes. Standard emissions in Chinese regions showed a rising and then declining trend from 2010 to 2019. The Northeast and Northwest regions of China demonstrated emission trends that were in sync with the growth in rural income. This study offers insights into the successes and challenges of LAGDs in achieving a balance between reduced emissions and development, using quantitative analysis. The findings are instrumental in informing policies for a sustainable livestock and poultry industry. Recommendations include evaluating coordinated approaches to pollution reduction and industrial growth, setting decoupling goals, designing policies based on influential factors, conducting regional assessments of livestock and poultry demand, and implementing region-specific strategies.

Recycling nitrogen from liquid digestate via novel reactive struvite and zeolite minerals to mitigate agricultural pollution

Recycling nutrients is of paramount importance. For this reason, struvite and nitrogen enriched zeolite fertilizers produced from wastewater treatments are receiving growing attention in European markets. However, their effects on agricultural soils are far from certain, especially struvite, which only recently was implemented in EU Fertilizing Product Regulations. In this paper, we investigate the effects of these materials in acid sandy arable soil, particularly focusing on N dynamics, evaluating potential losses, transformation pathways, and the effects of struvite and zeolitic tuffs on main soil biogeochemical parameters, in comparison to traditional fertilization with digestate. Liming effect (pH alkalinization) was observed in all treatments with varying intensities, affecting most of the soil processes. The struvite was quickly solubilized due to soil acidity, and the release of nutrients stimulated nitrifying and denitrifying microorganisms. Zeolitic tuff amendments decreased the NO_x gas emissions, which are precursors to the powerful climate altering N₂O gas, and the N enriched chabazite tuff also recorded smaller NH₃ emissions compared to the digestate. However, a high dosage of zeolites in soil increased NH₃ emissions after fertilization, due to pronounced pH shifts. Contrasting effects were observed between the two zeolitic tuffs when applied as soil amendments; while the chabazite tuff had a strong positive effect - increasing up to ∼90% the soil microbial N immobilization - the employed clinoptilolite tuff had immediate negative effects on the microbial biomass, likely due to the large quantities of sulphur released. However, when applied at lower dosages, the N enriched clinoptilolite also contributed to the increase of microbial N. From these outcomes, we confirm the potential of struvite and zeolites to mitigate the outfluxes of nutrients from agricultural systems. To gain the best results and significantly lower environmental impacts, extension practitioners could give recommendations based on the soils that are planned for zeolite application.

Optimization and modeling of ammonia nitrogen removal from anaerobically digested liquid dairy manure using vacuum thermal stripping process

During anaerobic digestion (AD) of liquid dairy manure, organic nitrogen converts to ammonia nitrogen (NH₃-N) and subsequently escalates the NH₃-N concentrations in manure. Among different available NH₃-N removal processes treating anaerobically digested liquid dairy manure (ADLDM), vacuum thermal stripping is reported to be an effective technique. However, none of the studies have performed multi-parameter optimization, which is of utmost significance in maximizing process efficiency. In this study, critical operational parameters for vacuum thermal stripping of NH₃-N from ADLDM were optimized and modeled for the first time via integrating grey relational analysis (GRA)-based Taguchi design, response surface methodology (RSM), and RSM-artificial neural network (ANN). The initial experimental trials conducted using the GRA coupled with Taguchi L₁₆ orthogonal array revealed the order of influence of the process parameters on NH₃-N removal as vacuum pressure (kPa) > temperature (°C) > treatment time (min) > mixing speed (rpm) > pH. The values of the first three most influential operating parameters were then further optimized and modeled using RSM and RSM-ANN models. Under the optimized conditions (temperature: 69.6 °C, vacuum pressure: 43.5 kPa, and treatment time: 87.65 min), the NH₃-N removal efficiency of 93.58 ± 0.59 % was experimentally observed and was in line with the RSM and RSM-ANN models' predicted values. While the RSM-ANN model showed a better prediction potential than did the RSM model when compared statistically. Moreover, the nutrient contents (nitrogen, N and sulfur, S) of the recovered NH₃-N as ammonium sulfate ((NH₄)₂SO₄) were in reasonable agreement with the market-available (NH₄)₂SO₄ fertilizer. The results presented in this study provide important insights into improving the treatment process performance and will help design and operate future pilot- and full-scale vacuum thermal stripping processes in dairy farms.

Ammonia and greenhouse emissions from cow's excreta are affected by feeding system, stage of lactation and sampling time

Decomposition of dairy cows' excreta on housing floor leads to ammonia and greenhouse gases production, yet factors affecting total emissions have not been fully disclosed. This work aimed to assess the impact of lactation stage, feeding system and sampling time on gaseous emission potential of cow's faeces and urine in laboratory chambers systems. Individual faeces and urine were collected from two groups of four cows, at peak and post peak lactation, from three commercial farms with distinct feeding systems: total mixed ration (TMR), total mixed ration plus concentrate at robot (TMR + robot), and total mixed ration plus concentrate in automatic feeders (TMR + AF). Samples were collected before a.m. (T8h), at middle day (T12h), and before p.m. (T17h) milking. In a laboratory chambers system, faeces and urine were mixed in a ratio of 1.7:1, and ammonia and greenhouse gases emissions were monitored during 48-h. Cumulative N-N₂O emissions were the highest in TMR + robot system, post peak cows and sampling time T17h. An interaction between stage of lactation and sampling time was detected for N-NH₃ and N-N₂O (g/kg organic soluble N) emissions. Post peak cows also produced the highest cumulative N-NH₃ emissions. Overall results contribute for the identification of specific on-farm strategies to reduce gaseous emissions from cows' excreta.

Dietary Change and Global Sustainable Development Goals

Food production for human consumption is a leading cause of environmental damage in the world and yet over two billion people suffer from malnutrition. Several studies have presented evidence that changes in dietary patterns across the world can lead to win-win outcomes for environmental and social sustainability and can complement ongoing technological and policy efforts to improve the efficiency of agricultural production. However, the existing evidence have been compiled in “silos” by a large range of researchers across several disciplines using different indicators. The aim of this quantitative review is to bring together the existing knowledge on heterogeneity of current dietary patterns across the world and how a transition toward healthy diets in different countries can aid in progress toward multiple global Sustainable Development Goals (SDGs). We first summarize the nutritional quality, economic cost, and environmental footprint of current diets of over 150 countries using multiple indicators. Next, we review which shifts in dietary patterns across different world regions can help toward achievement of SDG2 (Zero hunger), SDG3 (Good health and wellbeing), SDG 6 (Clean water and sanitation), SDG13 (Climate action), SDG14 (Life below water), and SDG15 (Life on land). Finally, we briefly discuss how to enable the shift toward sustainable dietary patterns and identify the research and data gaps that need to be filled through future efforts. Our analysis reveals that dietary change is necessary in all countries as each one has unique priorities and action items. For regions such as Sub-Saharan Africa and South Asia, increased intake of nutrient dense foods is needed to address deficiency of essential nutrients like folate, potassium, and vitamin A. For North America and Europe, shifting toward more plant-based diets would be healthier and simultaneously reduce the per capita environmental footprints. The results can be useful for policymakers in designing country-specific strategies for adoption of sustainable dietary behaviors and for food industry to ensure the supply of sustainable food items customized with regions' need.

Effects of rumen undegradable protein sources on nitrous oxide, methane and ammonia emission from the manure of feedlot-finished cattle

The effects of sources of rumen undegradable protein (RUP) in diets on methane (CH₄), nitrous oxide (N₂O) and ammonia (NH₃) emissions from the manure of feedlot-finished cattle were evaluated. We hypothesized that the use of different RUP sources in diets would reduce N loss via urine and contribute to reduced N₂O, CH₄ and NH₃ emissions to the environment. Nellore cattle received different diets (18 animals/treatment), including soybean meal (SM, RDP source), by-pass soybean meal (BSM, RUP source) and corn gluten meal (CGM, RUP source). The protein source did not affect the N and C concentration in urine, C concentration in feces, and N balance (P > 0.05). The RUP sources resulted in a higher N₂O emission than the RDP source (P = 0.030), while BSM resulted in a higher N₂O emission than CGM (P = 0.038) (SM = 633, BSM = 2521, and CGM = 1153 g ha⁻² N–N₂O); however, there were no differences in CH₄ and NH₃ emission (P > 0.05). In conclusion, the use of RUP in diets did not affect N excretion of beef cattle or CH₄ and NH₃ emission from manure, but increased N₂O emission from the manure.

High ambient humidity aggravates ammonia-induced respiratory mucosal inflammation by eliciting Th1/Th2 imbalance and NF-κB pathway activation in laying hens

Ammonia (NH₃) is an irritant and harmful gas. Its accumulation in the poultry house poses detrimental effects on the respiratory mucosal system of birds. In this process, the relative humidity of the poultry house also plays an important role in potentiating the adverse effects of NH₃ on the respiratory status of birds, causing severe physiological consequences. In this study, the combined effects of NH₃ and humidity on the respiratory mucosal barrier of laying hens was studied. The gene expression of tight junction proteins, mucin, inflammatory cytokines secreted by Th1/Th2 cells, and proteins related to the Nuclear factor-κB (NF-κB) signaling pathway were detected by qRT-PCR. In addition, the contents of mucin and secretory immunoglobulin A (SIgA) in bronchoalveolar lavage fluid (BALF) were determined. The results showed that treatment with NH₃ alone or NH₃ and humidity led to morphological changes in the respiratory tract, decreased the gene expressions of tight junction protein, and increased the expression of mucin. Also, the expression of interleukin-4 (IL-4) and IL-10 were increased, whereas, the expression of interferon-γ (IFN-γ) and IL-2 was decreased in laying hens treated with NH₃ and humidity. Furthermore, the activation of inhibitor kappa B kinase β (I-KK-β) and the degradation of inhibitor of NF-κB α (I-κB-α) contributed to the activation of the NF-κB pathway, such that the downstream genes, cycooxygenase 2 (COX2) and inducible nitric oxide synthase (iNOS) were significantly increased. In conclusion, NH₃ damaged the mucosal barrier and induced an imbalance in the mucosal immunity, leading to respiratory tract inflammation. Thus, the relative humidity of the environment aggravates the adverse effects of NH₃ in poultry.

A figure of merits-based performance comparison of various advanced functional nanomaterials for adsorptive removal of gaseous ammonia

The implementation of sustainable industrial development based on energy/cost-effective techniques with zero/low rate of pollutant emission is an ideal strategy for the proper management of a natural environment. Gaseous ammonia released from a variety of anthropogenic sources (e.g., agriculture, pharmaceuticals, commercial cleaning products, and refrigerant) is estimated to be as high as 150 million tons∙year^-1. To reduce the negative effects of atmospheric ammonia, the great utility of advanced functional nanomaterials (e.g., metal organic frameworks, covalent organic polymers, metal/metal oxide nanoparticles, and carbon nanostructures) has been recognized. To gain a better understanding of the sorptive removal potential of diverse materials, their performance has been evaluated based on the key performance merits (e.g., initial concentration, sorption capacity, and partition coefficient). Generally, the PC values can be applied to significantly estimate the contaminant adsorption potential of NMs via balancing the biased influences of operating parameters (e.g., initial concentration of pollutants) as perceived for the partitioning of compounds between aqueous phases at equilibrium (e.g., Henry's Law). Therefore, in this work, we have proposed the PC as a prosperous performance merit (in terms of heterogeneity of surface and strength of adsorption process) for the selection of high performance nano-adsorbents for gaseous ammonia. Moreover, the water stability, recyclability, economic aspects, and future perspectives have also been discussed for real-world applications of advanced nanomaterial against gaseous ammonia adsorption. The outcome of this evaluation will be expedient for the classification/selection of the most effectual and cost-effective options for mitigation of environmental pollutants like gaseous ammonia.

Impact of Livestock Farming on Nitrogen Pollution and the Corresponding Energy Demand for Zero Liquid Discharge

Intensive livestock farming has negatively impacted the environment by contributing to the release of ammonia and nitrous oxide, groundwater nitrate pollution and eutrophication of rivers and estuaries. The nitrogen footprint calculator has predicted the large impact of meat production on global nitrogen loss, but it could not form the relationship between meat production and the corresponding manure generation. Here we report on the formation of direct relationships between beef, pork and poultry meat production and the corresponding amount of nitrogen loss through manure. Consequently, the energy demand for ammonium nitrogen recovery from manure is also reported. Nitrogen loss to the environment per unit of meat production was found directly proportional to the virtual nitrogen factors. The relationship between total nitrogen intake and the corresponding nitrogen loss per kg of meat production was also found linear. Average nitrogen loss due to manure application was calculated at 110 g kg−1 for poultry. The average nitrogen loss increased to 190 and 370 g-N kg−1 for pork and beef productions, respectively. Additionally, 147 kg ammonium nitrogen was calculated to be recovered from 123 m3 of manure. This corresponded to 1 Mg of beef production. The recovery of ammonium nitrogen was reduced to 126 and 52 kg from 45 and 13 m3 of pork and poultry manure, respectively. The ammonium nitrogen recovery values were calculated with respect to 1 Mg of both pork and poultry meat productions. Consequently, the specific energy demand of ammonium nitrogen recovery from beef manure was noticed at 49 kWh kg−1, which was significantly 57% and 69% higher than that of pork and poultry manure, respectively.

Comparison of nitrogen losses from different manure treatment and application management systems in China

There is a worldwide focus on reducing the environmental impacts of livestock manure management. In China, there are different manure treatment and application modes, including complete treatment to remove nitrogen (N) for direct discharge into watercourses. But we lack a systematic quantitative comparison of the environmental losses that occur from different management modes. We used an example farm of 10,000 finisher pigs to quantitatively analyze the annual N losses from land application (LA) and treatment to remove N from manure to the level of discharge consent (DS) under 24 sub-modes. This is an important study to unravel the effect of choice of different manure management systems on subsequent N losses. The results showed that the N losses from the LA mode (52.6% of total N excretion) were significantly lower than that from the DS mode (75.9%). Compared with other sub-modes, N emission from whole slurry injection was the smallest, accounting for 43.2% of total N excretion. NH₃-N was the main source of N loss which accounted for 72.9% and 50.2% in LA and DS mode, respectively. The lowest N emission of LA mode with mitigation options, including slurry store covers, composting with bio-filter deodorization and injection application, was 28.8% of total N excretion, which is only 42.2% of N emission from DS mode with mitigation options. Insights from this systematic study of different manure management modes in China show the imperative of control ammonia emission for China, and provide guidance to the sustainable manure management in rapidly developing countries.

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.

Bio-membrane integrated systems for nitrogen recovery from wastewater in circular bioeconomy

Wastewater contains a significant amount of recoverable nitrogen. Hence, the recovery of nitrogen from wastewater can provide an option for generating some revenue by applying the captured nitrogen to producing bio-products, in order to minimize dangerous or environmental pollution consequences. The circular bio-economy can achieve greater environmental and economic sustainability through game-changing technological developments that will improve municipal wastewater management, where simultaneous nitrogen and energy recovery are required. Over the last decade, substantial efforts were undertaken concerning the recovery of nitrogen from wastewater. For example, bio-membrane integrated system (BMIS) which integrates biological process and membrane technology, has attracted considerable attention for recovering nitrogen from wastewater. In this review, current research on nitrogen recovery using the BMIS are compiled whilst the technologies are compared regarding their energy requirement, efficiencies, advantages and disadvantages. Moreover, the bio-products achieved in the nitrogen recovery system processes are summarized in this paper, and the directions for future research are suggested. Future research should consider the quality of recovered nitrogenous products, long-term performance of BMIS and economic feasibility of large-scale reactors. Nitrogen recovery should be addressed under the framework of a circular bio-economy.

Effect of a Mineral-Microbial Deodorizing Preparation on the Functions of Internal Organs and the Immune System in Commercial Poultry

Animal production is identified as one of the main sources of high concentrations of odours, which are related to air pollution, health problems of living organisms and indirect negative impact on production results. One common method for reducing emissions of ammonia is using preparations containing probiotics and hygroscopic or disinfecting compounds. This study was undertaken in order to determine the impact of innovative mineral-microbial deodorizing preparation, which reduces odorous gases, applying to the litter once a week in poultry houses on the physiological status of breeder chickens, broiler chickens and turkeys. Samples were collected after slaughter and analyzed using ELISA tests, flow cytometry and biochemical methods. Biochemical markers of the liver and kidney profile (ALT, AST, LDH, ALP, CK, TP, CALC, PHOS) and the titers of specific antibodies against AEV, aMPV, AAvV-1, IBDV, HEV, BA were analyzed in serum samples. The percentage contribution of T and B lymphocyte subpopulations was determined in the samples of tracheal mucosa, blood, and spleen. No significant differences were found between the control and experimental group with regard to all the analyzed parameters, with some exceptions for biochemistry. The results of our study indicated that mineral-microbial deodorizing preparation did not affect the physiological status of birds.

Ammonia and nitrous oxide emission factors for excreta deposited by livestock and land-applied manure

Manure application to land and deposition of urine and dung by grazing animals are major sources of ammonia (NH₃ ) and nitrous oxide (N₂ O) emissions. Using data on NH₃ and N₂ O emissions following land-applied manures and excreta deposited during grazing, emission factors (EFs) disaggregated by climate zone were developed, and the effects of mitigation strategies were evaluated. The NH₃ data represent emissions from cattle and swine manures in temperate wet climates, and the N₂ O data include cattle, sheep, and swine manure emissions in temperate wet/dry and tropical wet/dry climates. The NH₃ EFs for broadcast cattle solid manure and slurry were 0.03 and 0.24 kg NH₃ -N kg^-1 total N (TN), respectively, whereas the NH₃ EF of broadcast swine slurry was 0.29. Emissions from both cattle and swine slurry were reduced between 46 and 62% with low-emissions application methods. Land application of cattle and swine manure in wet climates had EFs of 0.005 and 0.011 kg N₂ O-N kg^-1 TN, respectively, whereas in dry climates the EF for cattle manure was 0.0031. The N₂ O EFs for cattle urine and dung in wet climates were 0.0095 and 0.002 kg N₂ O-N kg^-1 TN, respectively, which were three times greater than for dry climates. The N₂ O EFs for sheep urine and dung in wet climates were 0.0043 and 0.0005, respectively. The use of nitrification inhibitors reduced emissions in swine manure, cattle urine/dung, and sheep urine by 45-63%. These enhanced EFs can improve national inventories; however, more data from poorly represented regions (e.g., Asia, Africa, South America) are needed.

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

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

Innovative high digestibility protein feed materials reducing environmental impact through improved nitrogen-use efficiency in sustainable agriculture

Sustainable development in agriculture brings both environmental and economic benefits. Contemporary agriculture is also about increasing nutrient use efficiency, especially nitrogen, as the critical nutrient causing the most significant environmental pressure. This creates the need to produce highly digestible protein feed with high bioavailability, reducing losses of biogenic elements to feces. In this review, the latest trends and the potential for their implementation in sustainable agriculture have been compared, as well as the need to reduce the negative environmental impact of agriculture has been demonstrated. Applying local protein sources to feed animals reduces greenhouse gas emissions associated with transportation. The production of highly digestible fodder leads to a reduction in environmental pollution caused by excessive nitrogen outflows. Another approach indecreasing ammonia emissions from livestock farming is feed protein reduction and amino acid supplementation. All of the aforementioned approaches may result in beneficial long-term changes, contributing to environmental safety, animal welfare and human health.

Annual Nitrogen Balance from Dairy Barns, Comparison between Cubicle and Compost-Bedded Pack Housing Systems in the Northeast of Spain

Simple Summary

Environmental concerns related to livestock production have driven the importance of developing manure-management alternatives to mitigate N emissions. Hence, we carried out measurements of N loss in two different dairy housing systems (compost-bedded pack vs. cubicles), each system with a very distinct manure-management procedure. Since each system performs different manure-management practices, it may be important to compare their efficiency in terms of N recovery from manure in both systems. In contemplation of annual temperature variation, measurements of N recovery after manure management were carried out during warm and cold seasons of the year. Significantly higher volatilization rates were found in compost-bedded pack system with respect to cubicles system, therefore, N left in manure was lower in compost-bedded pack barns.

Abstract

The aim of this study was to determine N recovery and irreversible losses (i.e., through NH₃-N volatilization) from manure in two different housing systems throughout a year using an N mass balance approach. Dietary, milk, and manure N were monitored together with outside temperatures in six dairy barns during six months, comprising two different seasons. Three barns were designed as conventional free stalls (cubicle, CUB) and the other three barns as compost-bedded packs (CB). All the barns were located in the Ebro’s valley, in the northeast of Spain. Mass N balance was performed simultaneously in the six barns, during two three-month periods (Season I and II) and sampling at a 15-day interval. Results of ANOVA analysis showed that annual N retained in manure (kg/head per year) from cows housed in CUB barns was significantly higher than in manure from cows housed in CB (133.5 vs. 70.9, p < 0.001), while the opposite was observed for N losses (26.9 vs. 84.8, for CUB and CB barn, respectively; p < 0.005). The annual mean proportion of irreversible N loss from manure in relation to N intake was much lower in barns using conventional free-stall cubicles than the mean ratio registered in bedded pack systems barns.

Assessment of Nitrogen Flows at Farm and Regional Level When Developing the Manure Management System for Large-Scale Livestock Enterprises in North-West Russia

Arranging efficient manure management is the major environmental challenge in livestock farming in the Leningrad Region, with manure nitrogen being regarded as the main pollution source. The study aimed to identify the baselines for taking integrated manure management decisions towards reducing nitrogen losses applying nitrogen surplus and nitrogen use efficiency (NUE) as indicators calculated at the regional and municipal district level. At the regional level, NUE was found to be 34% and N surplus was 103 kg ha−1. Eleven “environmentally friendly” districts had a mean NUE of 59%, a mean N surplus 39.6 kg ha−1 and a mean animal density 0.89 LSU ha−1. Four districts were identified as “hot spots”, with an animal density in the range from 2.6 to 67 LSU ha−1, NUE from 1 to 37% and N surplus from 87 to 3082 kg ha−1. A scenario was suggested for the redistribution of organic fertilisers between “hot spots” and “environmentally friendly” districts, allowing each district to increase the N surplus to the regional value. Nitrogen flows and measures improving NUE at the farm level through organisational activity and advanced practices were considered with the help of the “N input − N output” diagram and the example of the nitrogen flows on a pilot dairy farm.

Societal benefits of halving agricultural ammonia emissions in China far exceed the abatement costs

Mitigating agricultural ammonia (NH₃) emissions in China is urgently needed to avoid further damage to human and ecosystem health. Effective and feasible mitigation strategies hinge on integrated knowledge of the mitigation potential of NH₃ emissions and the associated economic costs and societal benefits. Here we present a comprehensive analysis of marginal abatement costs and societal benefits for NH₃ mitigation in China. The technical mitigation potential of agricultural NH₃ emissions is 38–67% (4.0–7.1 Tg N) with implementation costs estimated at US$ 6–11 billion. These costs are much lower than estimates of the overall societal benefits at US$ 18–42 billion. Avoiding unnecessary fertilizer use and protein-rich animal feed could provide 30% of this mitigation potential without additional abatement costs or decreases in agricultural productivity. Optimizing human diets with less animal-derived products offers further potential for NH₃ reduction of 12% by 2050.

Global largest agricultural ammonia (NH₃) emissions in China have caused severe damage to both ecosystem and human health, yet no policy is formulated to reduce NH₃ emissions. Here, the authors show that halving agricultural NH₃ emissions with feasible technical mitigation options in China generates far more societal benefits than abatement costs.

NF-κB pathway took part in the development of apoptosis mediated by miR-15a and oxidative stress via mitochondrial pathway in ammonia-treated chicken splenic lymphocytes

Ammonia, a kind of gas with pungent smell, is harmful to livestock and people, and has bad influence on the atmosphere. However, the mechanism of splenic toxicity caused by ammonia is still poorly understood. The aim of present study was to investigate the effect of ammonia on chicken splenic lymphocytes from the perspective of apoptosis. Chicken splenic lymphocytes were divided into the control group and the two ammonium treatment groups (1 mmol/L and 5 mmol/L ammonia), and were cultured for 24 h. CCK-8, flow cytometry (FC), fluorescence microscope, quantitative real-time PCR (qRT-PCR), and Western blot were used to study the differences between different groups. The results showed that ammonia exposure increased the release of calcium (Ca)²⁺ and reactive oxygen species (ROS) from mitochondrion. Besides, we found an increase in mRNA levels of glutathione peroxidase (GPx), inflammation-related genes (nuclear factor-κB (NF-κB), cyclooxygenase-2 (COX-2), inducible nitric (iNOS), tumor necrosis factor-α (TNF-α), and transforming growth factor-β (TGF-β)), apoptosis-related genes (B-cell lymphoma-2 (BCL-2), Bcl-2 associated X protein (BAX), Cytochrome c (Cytc), apoptotic protease activating factor 1 (APAF1), Caspase-9, and Caspase-3), and an increase in protein levels of NF-κB, iNOS, BAX, Cytc, Caspase-9, and Caspase-3. At the same time, we found a decrease level of GPx protein expression, and a decrease level of glutathione S-transferase (GST) mRNA expression, and a decrease level of heme oxygenase-1 (HO-1) and BCL-2 mRNA and protein expression in splenic lymphocytes exposed to ammonia. Meanwhile, miR-15a expression increased under ammonia exposure. In summary, these results indicated that ammonia induced oxidative stress, promoted the release of Ca²⁺, Cytc, and ROS from mitochondria, and then induced mitochondria-mediated inflammatory response, finally triggered apoptosis in chicken splenic lymphocytes.

Low Protein-High Carbohydrate Diets Alter Energy Balance, Gut Microbiota Composition and Blood Metabolomics Profile in Young Pigs

Reducing dietary crude protein (CP) beyond a certain threshold leads to poor growth performance in pigs; however, the underlying mechanisms are not well understood. Following an adaption period, thirty-seven weaned pigs were weight matched (8.41 ± 0.14 kg), housed individually and randomly assigned into three groups with different dietary CP levels: 24% CP (CON; n = 12), 18% CP (n = 12) and 12% CP (n = 13) for 28 days. The body weight was not different between the CON and 18% CP diets, but 12% CP significantly decreased body weight after day 21. Compared to the CON, pigs fed with 12% CP decreased feed intake day 17 onwards. The 12% CP diet increased the energy expenditure during week 1 compared to the CON. The 12% CP influenced starch and sucrose, nitrogen, and branched-chain amino acids metabolism pathways. The feces of pigs fed with 12% CP were less enriched in Prevotella, but had higher relative abundance of Christensenedilaceae, Aligiphilus and Algoriphagus than CON and 18% CP. Overall, reducing dietary CP by 50%, but not by 25%, significantly influenced the physiological responses in nursery pigs. The pigs fed with low or standard protein diets had differential bacterial communities in their feces as well as serum metabolomics profile.