High Ammonia Levels Research Articles

Comparison of ammonia thresholds for survival and reproduction between two copepods: The planktonic calanoid Eurytemora affinis and the benthic harpacticoid Tigriopus japonicus

The planktonic species Eurytemora affinis and the benthic species Tigriopus japonicus are two copepods that are extensively employed in aquaculture operations, especially as a source of live feed during larval rearing. Compared to T. japonicus, E. affinis is difficult to keep in stable cultures and to mass produce, which largely limits its usage. Furthermore, high levels of un-ionized ammonia (NH3−N) can limit the productivity of aquatic organisms. However, the toxicity of NH3-N can be easily affected by environmental conditions. The planktonic and benthic growth features of E. affinis and T. japonicus may reflect different adaptations to NH3−N stress that could affect their reproductive performances. Hence, we investigated the effect of NH3−N on the survival and reproductive patterns of E. affinis and T. japonicus at both the individual and population levels. The median lethal concentrations for both the nauplius and copepodite stages, life history parameters, and population growths of each species were evaluated after acute (24-h) and chronic (21–28 days) NH3−N exposure. The results showed that E. affinis was more vulnerable to NH3−N stress than T. japonicus at all developmental stages. The nauplius and copepodite stages of E. affinis exhibited 14.7- and 33.7-fold lower 24-h LC50 doses, respectively, than those of T. japonicus. Chronic individual exposure to NH3−N concentrations over a specific threshold (≥ 0.2 mg/L for E. affinis and ≥ 14.6 mg/L for T. japonicus) affected survival rates, extended the duration of the nauplius and copepodite stages, and delayed maturation in both species. In contrast, batch culture showed that low concentrations of NH3−N were beneficial to the reproduction of T. japonicus, whereas such a trend was not clearly observed in E. affinis. Finally, we hypothesize that the differences in the NH3−N sensitivities of E. affinis and T. japonicus could be attributed to their evolutionary history in pelagic and benthic habitats, respectively. The low NH3−N tolerance of E. affinis indicates the importance of managing ammonia levels during their cultivation.

Nanobubble Technology Enhanced Ozonation Process for Ammonia Removal

Ozone (O3) has been widely used for water and wastewater treatment due to its strong oxidation ability, however, the utilization efficiency of O3 is constrained by its low solubility and short half-life during the treatment process. Thereby, an integrated approach using novel nanobubble technology and ozone oxidation method was studied in order to enhance the ozonization of ammonia. Artificial wastewater (AW) with an initial concentration of 1600 mg/L ammonia was used in this study. In the ozone-nanobubble treatment group, the concentration of nano-sized bubbles was 2.2 × 107 particles/mL, and the bubbles with <200 nm diameter were 14 times higher than those in the ozone-macrobubble treatment control group. Ozone aeration was operated for 5 min in both nanobubble treatment and control groups, however, the sampling and measurement were conducted for 30 min to compare the utilization of O3 for ammonia oxidation. H+ was the by-product of the ammonia ozonation process, thus the pH decreased from 8 to 7 and 7.5 in nanobubble treatment and control groups, respectively, after 30 min of operation. The fast removal of ammonia was observed in both systems in the first 10 min, where the concentration of ammonia decreased from 1600 mg/L to 835 and 1110 mg/L in nanobubble treatment and control groups, respectively. In the nanobubble treatment group, ammonia concentrations kept the fast-decreasing trend and reached the final removal performance of 82.5% at the end of the experiment, which was significantly higher than that (44.2%) in the control group. Moreover, the first-order kinetic model could be used to describe the removal processes and revealed a significantly higher kinetic rate constant (0.064 min−1) compared with that (0.017 min−1) in the control group. With these results, our study highlights the viability of the proposed integrated approach to enhance the ozonation of a high level of ammonia in contaminated water.

Impact of Rapid pH Changes on Activated Sludge Process

The inhibition effect of rapid variations of pH in wastewater on activated sludge was investigated in laboratory-scale sequencing batch reactors (SBR). The toxic influence of pH 6.5 and 8.5 was examined. The experiment with pH 8.5 was preferable to formation of high FA concentration and showed a low risk of inhibition of second step nitrification (conversion of nitrites to nitrates). However, the reactor at pH 6.5 showed inhibition of first-step nitrification (conversion of ammonia to nitrites) caused by FNA formation. High ammonia levels caused a decrease in the overall microfauna population, whereas low–enhanced gymnamoebae, Zoogloea, and Chilodonella sp. population increased after 72 h of inhibition. Destructive acidic pH influence caused sludge washout from the reactor and, therefore, higher organic load on ASP and intensive sludge foam due to Zoogloea higher population.

Low cerebral energy metabolism in hepatic encephalopathy reflects low neuronal energy demand. Role of ammonia-induced increased GABAergic tone

Hepatic encephalopathy (HE) is a frequent and devastating but generally reversible neuropsychiatric complication secondary to chronic and acute liver failure. During HE, brain energy metabolism is markedly reduced and it remains unclear whether this is due to external or internal energy supply limitations, or secondary to depressed neuronal cellular functions - and if so, which mechanisms that are in play. The extent of deteriorated cerebral function correlates to blood ammonia levels but the metabolic link to ammonia is not clear. Early studies suggested that high levels of ammonia inhibited key tricarboxylic acid (TCA) cycle enzymes thus limiting mitochondrial energy production and oxygen consumption; however, later studies by us and others showed that this is not the case in vivo. Here, based on a series of translational studies from our group, we advocate the view that the low cerebral energy metabolism of HE is likely to be caused by neuronal metabolic depression due to an elevated GABAergic tone rather than by restricted energy availability. The increased GABAergic tone seems to be secondary to synthesis of large amounts of glutamine in astrocytes for detoxification of ammonia with the glutamine acting as a precursor for elevated neuronal synthesis of vesicular GABA.

Upgrading the performance of high solids feeding anaerobic digestion of chicken manure under extremely high ammonia level

Biogas production using high solids feeding anaerobic digestion has several benefits, including higher treatment capacity, lower energy requirements, and reduced volume of digestate. However, when chicken manure is used as a substrate, the process is prone to reactor instability due to ammonia inhibition. This study investigated the performance of three laboratory-scale anaerobic systems fed by chicken manure with total solids (TS) up to 15%, giving rise to total ammonia nitrogen (TAN) concentration of 7.5 g/L. The tolerance of the anaerobic system to ammonia inhibition was evaluated by operating three organic loading rates (OLR) in the range of 1.5–4.5 g-volatile solids (VS)/(L·d). The results showed that methane yield reached 0.33 L/g·VS under an OLR of 1.5 g-VS/(L·d), comparable to conventional wet-type process performance. The total volatile fatty acids (VFAs) were below 0.5 g/L, indicating a highly acceptable performance. The digestive performance deteriorated when the OLR was increased to 4.5 g-VS/(L·d) and highlighted the importance of selecting an appropriate OLR. The result may support the adoption of high solids feeding anaerobic treatment for nitrogen-rich materials.

Serial anaerobic digestion improves protein degradation and biogas production from mixed food waste

Optimization of the biogas generation process is important to achieve efficient degradation and high methane yield, and to reduce methane emissions from the digestate. In this study, serial digester systems with two or three biogas reactors were compared with a single reactor, with the aim of improving degree of degradation and methane yield from food waste and assessing adaptation of microbial communities to different reactor steps. All systems had the same total organic load (2.4 g VS/(L d)) and hydraulic retention time (55 days). Serial systems increased methane yield by >5% compared with the single reactor, with the majority of the methane being obtained from the first-step reactors. Improved protein degradation was also obtained in serial systems, with >20% lower outgoing protein concentration compared with the single reactor and increasing NH4+-N concentration with every reactor step. This resulted in separation of high ammonia (>384 mg NH3-N/L) levels from the main methane production, reducing the risk of methanogen inhibition. Methanosarcina dominated the methanogenic community in all reactors, but increases in the hydrogenotrophic genera Methanoculleus and Methanobacterium were observed at higher ammonia levels. Potential syntrophic acetate-oxidizing bacteria, such as MBA03 and Dethiobacteraceae, followed the same trend as the hydrogenotrophic methanogens. Phylum Bacteroidota family Paludibacteraceae was highly abundant in the first steps and then decreased abruptly, potentially linked to an observed decrease in degradation in the last-step reactors. Nevertheless, the results indicated a trend of increasing relative abundance of the potentially proteolytic genera Proteiniphilum and Fastidiosipila with successive reactor steps.

Sources of ammonium enriched in groundwater in the central Yangtze River Basin: Anthropogenic or geogenic?

The occurrence of excessive ammonium in groundwater threatens human and aquatic ecosystem health across many places worldwide. As the fate of ammonium in groundwater systems is often affected by a complex mixture of transport and biogeochemical transformation processes, identifying the sources of groundwater ammonium is an important prerequisite for planning effective mitigation strategies. Elevated ammonium was found in both a shallow and an underlying deep groundwater system in an alluvial aquifer system beneath an agricultural area in the central Yangtze River Basin, China. In this study we develop and apply a novel, indirect approach, which couples the random forest classification (RFC) of machine learning method and fluorescence excitation-emission matrices with parallel factor analysis (EEM-PARAFAC), to distinguish multiple sources of ammonium in a multi-layer aquifer. EEM-PARAFAC was applied to provide insights into potential ammonium sources as well as the carbon and nitrogen cycling processes affecting ammonium fate. Specifically, RFC was used to unravel the different key factors controlling the high levels of ammonium prevailing in the shallow and deep aquifer sections, respectively. Our results reveal that high concentrations of ammonium in the shallow groundwater system primarily originate from anthropogenic sources, before being modulated by intensive microbially mediated nitrogen transformation processes such as nitrification, denitrification and dissimilatory nitrate reduction to ammonium (DNRA). By contrast, the linkage between high concentrations of ammonium and decomposition of soil organic matter, which ubiquitously contained nitrogen, suggested that mineralization of soil organic nitrogen compounds is the primary mechanism for the enrichment of ammonium in deeper groundwaters.

The importance of plasma amino acid profiling in the diagnosis of inborn errors of metabolism: analytical – prospective study

Introduction. Inborn errors of metabolism (IEM) make up a large group of disorders caused by an inherited defect of proteins that have enzymatic, carrier, receptor or structural roles. The cumulative prevalence of IEM in different populations is around 1:500 – 800 newborns, despite the fact that some of these disorders are extremely rare when taken individually. Early recognition and intervention are essential to avoiding disastrous consequences associated with IEM. The phenotype of IEM patients is very heterogeneous and only in combination with specialized metabolic test it can lead to a correct diagnosis. The aim of the study was defined as evaluation of importance of plasma amino acid profile in the diagnosis of IEM. Material and methods. Plasma amino acids quantification have been performed by high performance liquid chromatography on Shimadzu LC-20 with post column derivatization with OPA in 15 patients aged from 0 to 13 years old, selected through medical genetic counseling, based on inclusion and exclusion criteria. Inform consent has been signed by parents after receiving all necessary information regarding the study. Additionally, liquid chromatography-tandem mass spectrometry (LC-MS/MS) on dried blood spots and Nuclear Magnetic Resonance Spectroscopy (H1-NMR) on urine has been done as complementary tests. Results. The first line investigations showed acid-base imbalance (33,3%), hypoglycemia (46,6%), high lactate level (46,6%) and high ammonia level (20%). Plasma amino acid concentrations were abnormal in 4 patients (27%). Increased glycine (544 μmol/L, reference values 70,72 – 256,36 μmol/L), along with elevated glycine in cerebrospinal fluid (CSF) / plasma ratio (0,147, normal < 0.02) was detected in a patient with seizures, coma, and respiratory arrest indicating non-ketotic hyperglycinemia. High level of phenylalanine (Phe 1568µmol/L, reference values 26.52 – 221 µmol/L) has been identified in a patient suspected for Phenylketonuria after neonatal screening results (Phe > 3mg/dL). Also the ratio Phe / Tyr around 17 was specifically appreciated as for classical form of PKU. High alanine concentration (> 450 µmol/L) has been observed in two patients presenting severe metabolic acidosis and high lactate level, suggesting for a metabolic error with mitochondrial involvement. The results from extended newborn screening and NMR spectroscopy narrowed the spectrum of suspected diseases, facilitating the diagnosis. Molecular genetic tests are required for the confirmation of disease in all cases. Conclusions. Quantitative amino acids analysis is an important tool for the diagnosis of “intoxication type” of IEMs and nutritional monitoring of individuals with already established diagnosis.

Inhibition mechanisms of ammonia and sulfate in high-solids anaerobic digesters for food waste treatment: Microbial community and element distributions responses

The horizontal flow anaerobic digester indicated that high ammonia (2923 mg/L) and SO42− (3653 mg/L) would influence the performance of methane production with food waste as substrates. Therefore, bottle anaerobic digestion reactors were carried out to investigate the effect of ammonia/sulfate concentrations on the methane production. Experimental results manifested that the anaerobic digesters with an ammonia concentration of 3500 mg/L or sulfate of 1600 mg/L showed the best performance of methane production, with an average methane yield of 0.32 and 0.33 L (g VS)−1 d−1, respectively. Specifically, a higher ammonia (6500 mg/L) or sulfate (1600-3500 mg/L) level hindered the bioconversion of C from liquid to gas phase (2.68% or 1.73% CH4-Gas, respectively), while insignificantly for the hydrolyzation of C and N from solid to liquid phase. Similar to sulfate, high ammonia nitrogen seriously inhibited the methanation process, leading to a significant carbon accumulation in the anaerobic reactor, especially for propionic acid. The predominant archaea Methanosarcina at genus level indicated that aceticlastic methanogenesis was the major methanogenic pathway. Meanwhile, high ammonia level suppressed the activity of Methanosarcina, while modest sulfate improved H2-consuming methanogens activity. A large fraction of unclassified bacteria within the Firmicutes (43.78%-63.17%) and Bacteroidetes (24.20%-33.30%) phylum played an important role in substrates hydrolysis.

Zinc bioremediation in soil by two isolated L-asparaginase and urease producing bacteria strains

Since urease-based microbial induced calcium carbonate precipitation (MICCP) process produces high ammonia levels, alternative strategies are very useful in adopting the MICCP process for bioremediating heavy metals. This study aimed to investigate the potential application of two native L-asparaginase and urease-producing isolates and Sporosarcina pasteurii as an indicator strain in removing zinc (Zn) from a contaminated solution and immobilizing it in soil through MICCP method. Zn removal from contaminated solution was 70.36% and 71.46% in 4 mmol L−1 Zn by S. pasteurii and urease-producing isolate, respectively. However, it was 97.32% when L-asparaginase-producing isolate was inoculated in solution with doubled Zn concentration (8 mmol L−1 Zn). The overall mean reduction of Zn in soluble-exchangeable fraction of soil was the highest in L-asparaginase-producing isolate treatment (71.8%) in comparison to S. pasteurii (61.8%) and urease-producing isolate treatments (56.2%). In contaminated soil with 150, 300, 400, and 500 mg kg−1 Zn, carbonate-bound Zn fraction increased to 79.2–85.35% and 83.86–85.12% in soil inoculated with S. pasteurii and urease-producing isolate, respectively. However, this fraction increased to 80.67, 84.95, 85.45, and 86.05%, respectively, in the case of L-asparaginase-producing isolate inoculation. Overall, the results confirmed the efficacy of both isolated strains in removing and immobilizing Zn in comparison to the indicator strain, which indicated the higher potential of the L-asparaginase strain. Therefore, due to the less ammonia production, L-asparaginase based MICCP process can be considered as a more environmentally friendly approach for bioremediating soil heavy metal.

Fish sludge as a co-substrate in the anaerobic digestion of municipal sewage sludge- maximizing the utilization of available organic resources

The thriving of on-land based aquaculture at Norway's western region is to provide higher amounts of discharges to handle sustainably. Utilizing the sludge generated as a co-digestion substrate at already existing biogas plants treating sewage sludge may contribute to higher yields and improved nutrient recirculation. For this study, both wet and dried fish sludge samples were tested as co-substrates on the digestion of sewage sludge in semi-continuous bench-scale reactors. Additions of 30% in volatile solids (VS) of fish sludge gave a 35% methane production increase at mesophilic conditions. In thermophilic conditions the same addition caused process inhibition due to high ammonia levels obtained. Addition of up to 20% VS of dried fish sludge provided an increase between 30–50% in the yield. Fish sludge was verified as a promising co-substrate to increase the yield. However, heavy metals accumulation during the process caused the downgrading of the digested biomass as soil conditioner.

Improvement of SI engine combustion with ammonia as fuel: Effect of ammonia dissociation prior to combustion

Although recent studies have shown the possibility of running ‘standard’ spark-ignition engines with pure ammonia, the operating range remains limited mainly due to the unfavorable characteristics of ammonia for premixed combustion and often requires the addition of a complementary fuel such as H2 to extend it. As the best way to add H2 is to crack ammonia directly on-board, this paper focuses on the impact of the upstream cracking level of ammonia on the performance and emissions of a single cylinder spark ignition engine. Experiments were performed over several equivalence ratios, dissociation rates and load conditions. It is confirmed that only a slight rate of ammonia dissociation (10%) upstream of the combustion considerably enhances the engine's operating range thanks to a better combustion stability. In terms of pollutant emissions, the partial dissociation of ammonia, especially for slightly lean mixtures induces a very clear trade-off between high NOx and high unburned ammonia level for high and low ammonia dissociation rates, respectively. Therefore, cracking NH3 does not only improve the operating range of ammonia-fueled spark ignition engines but can also help to reduce NH3. However, to reach the same engine output work, higher ammonia fuel consumption will be necessary since the global system efficiency is lower using fuel dissociation. In addition, the global warming effect is increased with dissociation level since a higher level of N2O is generated by the hydrogen contribution.

Hyperammonemia of unknown cause in a young postpartum woman: a case report

BackgroundHyperammonemia is a medical condition described as increased or elevated serum ammonia levels. High serum levels of ammonia can cause neurotoxicity. Sudden onset severe hyperammonemia may cause severe encephalopathy with brain damage. It can result in cerebral edema, emesis, seizures, hypotonia, and death. We report a young postpartum woman who had a sudden rise in serum ammonia levels after vaginal delivery.Case presentationA 24-year-old, married, postpartum Pakistani woman was admitted to the intensive care unit through the emergency department, with complaints of fever, severe abdominal pain with distension, and altered levels of consciousness. The patient had a medical history of spontaneous vaginal delivery 2 weeks before this hospital admission, after which she gradually developed the above symptoms. However, the patient’s past medical history was unremarkable with no hepatic disease, but her investigations revealed a progressive rise in serum ammonia levels. In the intensive care unit, she developed generalized tonic–clonic seizures. This was followed by a coma, tonsillar herniation, and death.ConclusionPostpartum hyperammonemia is a rare entity. It is a critical illness and must be evaluated for underlying metabolic disorders. Early diagnosis and treatment may result in better outcomes and reduced mortality among postpartum women with hyperammonemia.

Exploring Different Pretreatment Methodologies for Allowing Microalgae Growth in Undiluted Piggery Wastewater

The overapplication of manure on agricultural soils leads to nitrogen and phosphorus discharge into the aquatic environment, resulting in serious eutrophication problems and decreased water quality. Piggery wastewater (PWW) can be treated by microalgae to recycle nutrients, but the toxic levels of ammonia and organic matter hinder their growth. Fresh water is usually used to dilute PWW, but it is a scarce resource. The implementation of a pretreatment step before microalgae-based treatment could make PWW suitable for microalgae growth. Electrocoagulation, ammonia stripping, photo-Fenton, and constructed wetlands were evaluated as pretreatment methods to reduce ammonia, chemical oxygen demand (COD), color, and total suspended solids. Moreover, the pretreated PWWs were tested to grow the microalga Tetradesmus obliquus. Photo-Fenton showed the best results among the other pretreatments, achieving removal efficiencies above 90%, except for ammonia. This resulted in T. obliquus being capable of growing on undiluted PWW, even at higher ammonia levels, achieving similar biomass productivity to synthetic medium (66.4 ± 17.8 mg·L−1·day−1 and 60.1 ± 10.4 mg·L−1·day−1, respectively) almost doubling with pH control (116.5 mg·L−1·day−1). Thus, this pretreatment seems to be the most promising one to incorporate into microalgae-based treatment systems and must be further explored.

Swine diets: Impact of carbohydrate sources on manure characteristics and gas emissions

Swine growers seeking to lower costs and environmental impact have turned to alternative carbohydrate feed sources. A feeding trial was conducted to determine the effect carbohydrate sources have on manure composition and gas emissions. A total of 48 gilts averaging 138 kg BW were fed diets consisting of (a) low fiber (LF) grain, or (b) high fiber (HF) aro-industrial co-product (AICP). The LF diets included corn and soybean meal (CSBM) and barley soybean meal (BSBM). The HF AICP diets were CSBM based and supplemented with one of the following materials: beet pulp; corn distillers dried grains with solubles; soybean hulls; or wheat bran. Diets were fed for 42 d with an average daily feed intake of 2.71 kg d−1. Feces and urine were collected twice daily and added to manure storage containers in which manure slurries were monitored for gas emissions and chemical properties. Manures of animals fed HF diets had significantly (P < 0.05) more excretion of solids, C, N, and organic N, but less total S compared to pigs fed the LF diets. Animals feed HF diets had significantly (P < 0.05) higher levels of ammonia, sulfide, volatile fatty acids, and phenols in manure compared to pigs fed the LF diets. Manure of animals fed HF diets had 30% (P < 0.05) lower NH3 and 17% lower hydrogen sulfide emissions; however, fiber had no impact on odor emissions. Based on the partitioning of nutrients, animals fed HF fiber diets had increased manure retention for C and N but decreased levels of N gas emissions and manure S. There were little differences in manure and gas emissions for animals fed LF diets, but the source of HF AICP diets had a significant impact on manure composition and gas emissions.

Geochemical factors controlling natural background levels of phosphate in various groundwater units in a large-scale urbanized area

Assessing natural background levels (NBLs) of groundwater chemical components is useful to the identification of geochemical factors controlling the origin of high levels of chemical components in groundwater. This study assessed the NBLs of phosphate in various groundwater units in the Pearl River Delta (PRD) where urbanization is a large-scale by the combination of a modified pre-selection method and Grubbs’ test, and discussed main geochemical processes controlling the origin of high levels of phosphate in groundwater. Here, the PRD is divided into four groundwater units according to its hydrogeological conditions. The modified pre-selection method consists of detected organic contaminants, the oxidation capacity, as well as the high levels of ammonium and nitrate in groundwater. Results showed that the NBL of phosphate in the coastal-alluvial aquifer was abnormal high (1.8 mg/L), and was >4 times that in other groundwater units. This is mainly attributed to the co-release of phosphate, bicarbonate, and Fe(II) accompanied with the elevated pH and decreased Eh, which resulted from the mineralization of organic matter accompanied with the reductive dissolution of Fe(III)-(hydr)oxides as well as the desorption of other secondary minerals such as aluminum oxyhydroxides in the overlaid marine stratum. Besides, unlike other groundwater units, the property of discharge area of the coastal-alluvial aquifer with more reducing environment also contributes the higher NBL of phosphate in the coastal-alluvial aquifer than in other groundwater units.

Air contamination of therapeutic drug monitoring assay reagents results in falsely high plasma ammonia levels.

Accumulating evidence shows that contamination of blood samples by atmospheric ammonia affects blood ammonia test levels; however, reports on the effect of ammonia contamination of assay reagents are limited. Here, we aimed to clarify the effect of ammonia contamination of assay reagents, particularly the therapeutic drug monitoring (TDM) reagents, on the detection levels of blood ammonia using enzymatic assays. Ammonia gas was measured in the refrigerator compartment of the automatic analyser and the reaction tank water, probe wash water and drain outlets connected to the automatic analyser. At different time points following the closure of the cold storage, ammonia levels in quality control plasma samples were measured using three commercial assay reagents to evaluate the effect of air contamination. The distribution of evaporated ammonia in the reagent was measured using the CicaLiquid NH3 assay kit containing the assay reagent most affected by air contamination. It was confirmed that ammonia gas was generated in the cold storage of the automatic analyser. More than half of the reagents detected >0.25 ppm ammonia, and the highest concentration was detected in the TDM reagent. The ammonia levels obtained using all three reagents increased significantly after 3h of air contamination. The effect was resolved by measuring a 'dummy' sample or mixing the reagents by inversion. We demonstrated that air contamination by TDM reagents placed in cold storage could result in significantly falsely high ammonia measurements. Preventing this effect would improve the accuracy of ammonia measurements.

Antimicrobial Efficacy of Un-Ionized Ammonia (NH3) against Salmonella Typhimurium in Buffered Solutions with Variable pH, NH3 Concentrations, and Urease-Producing Bacteria.

ABSTRACTThe presence of Salmonella in poultry litter, when used as a biological soil amendment, presents a risk for the preharvest contamination of fresh produce. Poultry litter is rich in organic nitrogen, and previous studies have suggested that ammonia (NH3) in poultry litter may affect the survival of Salmonella. Salmonella enterica serovar Typhimurium was inoculated into buffer solutions to characterize the pH dependency, minimum antimicrobial concentration, and efficacy of NH3 production. In solutions with 0.4 M total ammonia nitrogen (TAN) at various pH levels (5, 7, 8, and 9), significant inactivation of Salmonella only occurred at pH 9. Salmonella was reduced by ∼8 log CFU/mL within 12 to 18 h at 0.09, 0.18, 0.26, and 0.35 M NH3. The minimum antimicrobial concentration tested was 0.04 M NH3, resulting in an ∼7 log CFU/mL reduction after 24 h. Solutions with urea (1% and 2%) and urease enzymes rapidly produced NH3, which significantly reduced Salmonella within 12 h. The urease-producing bacterium Corynebacterium urealyticum showed no antagonistic effects against Salmonella in solution. Conversely, with 1% urea added, C. urealyticum rapidly produced NH3 in solution and significantly reduced Salmonella within 12 h. Salmonella inactivation data were nonlinear and fitted to Weibull models (Weibull, Weibull with tailing effects, and double Weibull) to describe their inactivation kinetics. These results suggest that high NH3 levels in poultry litter may reduce the risk of contamination in this biological soil amendment. This study will guide future research on the influence of ammonia on the survival and persistence of Salmonella in poultry litter.IMPORTANCE Poultry litter is a widely used biological soil amendment in the production of fresh produce. However, poultry litter may contain human pathogens, such as Salmonella, which introduces the risk of preharvest produce contamination in agricultural fields. Ammonia in poultry litter, produced through bacterial degradation of urea, may be detrimental to the survival of Salmonella; however, these effects are not fully understood. This study utilized aqueous buffer solutions to demonstrate that the antimicrobial efficacy of ammonia against Salmonella is dependent on alkaline pH levels, where increasing concentrations of ammonia led to more rapid inactivation. Inactivation was also demonstrated in the presence of urea and urease or urease-producing Corynebacterium urealyticum. These findings suggest that high levels of ammonia in poultry litter may reduce the risk of contamination in biological soil amendments and will guide further studies on the survival and persistence of Salmonella in poultry litter.

Current state of poultry waste management practices in Bangladesh, environmental concerns, and future recommendations.

This review paper focuses on the current state of poultry waste generation, composition, and management techniques in commercial poultry farms and trading in Bangladesh, to reduce pollution and generate economic benefits from poultry waste. It also underlines the negative impact of poultry waste disposal on the environment. In Bangladesh, collection of poultry waste into bags and, subsequently, direct use as fertilizer in agricultural fields and aquaculture is common, while alternative disposal methods such as composting and biogas generation are now attracting commercial poultry producers. Direct use of poultry manure results in poor air and soil quality, environmental deterioration, detrimental effects on global health, climate change due to high levels of atmospheric ammonia, and the creation of significant amounts of greenhouse gases. Lack of knowledge and investment, as well as high demand for free land for composting, are important obstacles. Future research on precise waste characterization, improved understanding of poultry waste management, and increased efforts on developed waste disposal for a safe environment are therefore recommended. So, poultry waste, which is currently a burden for the environment, could be turned into a useful agricultural resource, which would be useful for the poultry industry.

Novorođenče lečeno kontinuiranom terapijom zamene bubrežne funkcije za citrulinemiju-tip 1

Introduction: Hyperammonemia occurs as a result of the inability to convert ammonia, a metabolic toxin, into urea due to a block in the urea cycle, and there resulting neurotoxicity is responsible for the pathogenesis. Case Presentation: Our patient was 7 days old when followed up in an external center for 3 days with a preliminary diagnosis of neonatal sepsis. Lethargy, vomiting, tachypnea, and convulsions, which are frequently seen in the first neonatal forms of urea cycle disorders, were also present in our patient. He was referred to us as a result of high ammonia levels when he was examined in terms of congenital metabolic diseases. He was intubated due to the rapid development of respiratory failure. When he was admitted to our intensive care unit with hyperammonemia, light reflex could not be obtained, and widespread cutis marmaratus was developed. Continuous renal replacement therapy was started in our patient and administered intermittently for 120 hours. The glucose infusion rate was followed by high fluid. When it orally tolerated, it is supported with sodium benzoate and sodium stearyl fumarate to reduce ammonia. Nutrition was limited to protein with Basic P. Conclusion: After staying in the intensive care unit for 30 days, our patient was discharged with the recommendation of outpatient follow-up by the pediatric metabolism physician. When our patient came for his check up after two months,there was no nystagmus and no seizures.