Exposure to the environmental pollutant ammonia causes changes in gut microbiota and inflammatory markers in fattening pigs

Air treatment technologies in pig farms. Life cycle assessment of dry and wet scrubbers in Northern Italy and Northeastern Spain

Over the years, different solutions were developed and tested to reduce the emissions of ammonia and particulate matter from the livestock facilities. The environmental performances of these solutions were not always evaluated in detail. This study examines the environmental footprint of pig production at farm gate, with a focus on emissions from housing. Using Life Cycle Assessment, the environmental impact of pig production in a transition farm in Spain and in two finishing farms in Italy was evaluated considering three scenarios (one baseline and two of them involving an air treatment technology: wet scrubber or dry scrubber). The study goal was to quantify the environmental footprint of pig production in different scenarios, identify key environmental hotspots, and to assess impact reduction efficiency due to the two assessed technologies, analyze the environmental trade-offs that come with the use of these technologies, and identify potential for improvements. Both wet and dry scrubbers showed potential for reducing emissions in pig housing, affecting environmental impact categories related to air pollutants such as particulate matter, acidification and eutrophication. However, there were trade-offs between emissions reduction and categories related to energy and resource use. The infrastructure and consumables required to operate the scrubber added to the impacts compared to the baseline. The dry scrubber showed a more favorable balance between emission reduction and trade-offs. In this regard, results were similar for the Spanish and Italian farms, although there were slight variations. Scrubbers had a greater effect in the Italian farms due to their use along longer periods of the pig fattening (closed cycle farms) compared to the Spanish farm (transition farm). Scrubbers are environmentally promising, especially where acidification, eutrophication and particulate matter are local problems. However, they alone cannot fully address the complex environmental impacts of pig production, which require comprehensive interventions across the supply chain.

Biochar alleviates the crop failure of rice production induced by low-nitrogen cultivation mode by regulating the soil microbes taxa composition

To improve the nitrogen utilization efficiency and a series of environmental problems caused by excessive application of nitrogen fertilizer, actual agricultural production often reduced the usage ratio of nitrogen fertilizer. However, the reduction in nitrogen fertilizer not only affects the soil microenvironment but also leads to adverse effects on rice yield. Due to its unique properties, biochar can regulate soil nutrient distribution and significantly affect soil microbial community structure/functions. To further understand the effects of different levels of biochar on soil nutrient indicators, soil microorganisms and crop growth under the nitrogen-reduction condition, our experiment with four groups was set up as followed: 0%, 2.5% and 5% biochar application rates with 99 kg/hm2 nitrogen fertilizer and one control group (the actual fertilizer standard used in the field:110 kg/hm2) without no exogenous biochar supplement. The rice yield and soil nutrient indexes were observed, and the differences between groups were analyzed based on multiple comparisons. 16S ribosomal RNA and ITS sequencing were used to analyze the community structure of soil bacteria and fungi. Redundancy analysis was performed to obtain the correlation relationships between microbial community marker species, soil nutrient indexes, and rice yield. Path analysis was used to determine the mechanism by which soil nutrient indexes affect rice yield. The results showed that a higher application rate of biochar led to a significant increased trend in the soil pH, organic matter and total nitrogen content. In addition, a high concentration of biochar under nitrogen-reduction condition decreased the soil bacterial diversity but elevated the fungal diversity. Different concentrations of biochar resulted in these changes in the relative abundance of soil bacteria/fungi but did not alter the dominant species taxa. Taken together, appropriate usage for biochar under the nitrogen-reduction background could induce alteration in soil nutrient indicators, microbial communities and crop yields. These results provide a theoretical basis for exploring scientific, green and efficient fertilization strategies in the rice cultivation industry. Notably, the interaction relationship between rhizosphere microorganisms in rice and soil microbial taxa are not yet clear, so further research on its detailed effects on rice production is needed. In addition, the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis for the physiological functions of the soil microbes could only predict the potential metabolic pathways. Therefore, the next-generation metagenome techonology might be performed to explore detailed metabolic differences and accurate taxa alteration at the "species" level.

Effects of blackcurrant extract on indole and ammonia productions in an in vitro human fecal culture model

Blackcurrant is available as a traditional medicine in Europe. However, the detailed effects of blackcurrant on the human gut microbiota remain unknown. In this study, we investigated the prebiotic effects of a blackcurrant extract using a human fecal culture model in six healthy subjects. Feces were individually inoculated into a medium with or without the blackcurrant extract and then fermented for 48 hr under anaerobic conditions. The results obtained from analysis of samples from the fermented medium demonstrated that after 48 hr of fermentation, the pH of the medium with the blackcurrant extract was significantly decreased (control, 6.62 ± 0.20; blackcurrant extract, 6.41 ± 0.33; p=0.0312). A 16S rRNA gene sequencing analysis of the microbiota of the fermented medium showed a significant increase in the relative abundance of Bifidobacteriaceae. In measuring the concentrations of putrefactive components in the fermented medium, we found that the blackcurrant extract significantly reduced ammonia levels and displayed a tendency toward reduced indole levels. Our results suggest that blackcurrant extract could be a potential ingredient for relief of putrefactive components in the gut.

Lactobacillus plantarum Decreased Ammonia Emissions through Modulating Cecal Microbiotain Broilers Challenged with Ammonia

Probiotic supplementation has become a prominent method of decreasing ammonia emissions in poultry production. The present study was conducted to investigate the influence of Lactobacillus plantarum on ammonia emission, immune responses, antioxidant capacity, cecal microflora and short chain fatty acids, and serum metabolites in broilers challenged with ammonia. A total of 360 1-day-old yellow-feathered broilers were randomly divided into three treatment groups: birds fed with a basal diet (CON), a basal diet supplemented with ammonia (AN), and a basal diet supplemented with 2.5 × 108 CFU L. plantarum kg-1 and challenged with ammonia (LP). Data showed that L. plantarum supplementation decreased ammonia more than 30% from day 48, and significantly reduced the levels of serum urea nitrogen and ammonia, fecal urease, and ammonium nitrogen compared with those on CON. Compared with AN and CON treatments, LP administration increased (p < 0.05) the concentration of serum immunoglobulin Y (IgY), IgM, and IL-10, as well as the serum total-antioxidant capacity (T-AOC) and GSH-Px, and decreased (p < 0.05) IL-1β, IL-6, and TNF-α. Furthermore, birds supplemented with LP had higher (p < 0.05) cecal contents of short chain fatty acids (SCFAs) than AN birds and had more butyrate than CON birds. Data from 16s high throughput sequencing showed that LP supplementation significantly increased (p < 0.05) the Shannon and Simpson indices of bird cecal microflora, and Alloprevotella dominated the LP birds. The function prediction of cecal microflora indicated that LP treatment significantly increased alanine aspartate and glutamate metabolism, starch and sucrose metabolism, exosome, mismatch repair, homologous recombination, DNA repair and recombination proteins, and amino acid-related enzymes. The serum metabolome showed that LP supplementation significantly changed the aminoacyl-tRNA, pantothenate and acetyl-coenzyme A, arginine, phenylalanine, tyrosine and tryptophan, valine, leucine, and isoleucine biosynthesis; purine, beta-alanine, galactose, histidine, alanine, aspartate and glutamate, glyoxylate and dicarboxylate, pyruvate and thiamine metabolism, melanogenesis, and citrate cycle.

Review: Methods and biomarkers to investigate intestinal function and health in pigs

Society is becoming increasingly critical of animal husbandry due to its environmental impact and issues involving animal health and welfare including scientific experiments conducted on farm animals. This opens up two new fields of scientific research, the development of non- or minimally invasive (1) methods and techniques using faeces, urine, breath or saliva sampling to replace existing invasive models, and (2) biomarkers reflecting a disease or malfunction of an organ that may predict the future outcome of a pig's health, performance or sustainability. To date, there is a paucity of non- or minimally invasive methods and biomarkers investigating gastrointestinal function and health in pigs. This review describes recent literature pertaining to parameters that assess gastrointestinal functionality and health, tools currently used to investigate them, and the development or the potential to develop new non- and minimally invasive methods and/or biomarkers in pigs. Methods described within this review are those that characterise gastrointestinal mass such as the citrulline generation test, intestinal protein synthesis rate, first pass splanchnic nutrient uptake and techniques describing intestinal proliferation, barrier function and transit rate, and microbial composition and metabolism. An important consideration is gut health, and several molecules with the potential to act as biomarkers of compromised gut health in pigs are reported. Many of these methods to investigate gut functionality and health are considered 'gold standards' but are invasive. Thus, in pigs, there is a need to develop and validate non-invasive methods and biomarkers that meet the principles of the 3 R guidelines, which aim to reduce and refine animal experimentation and replace animals where possible.

Selenium Mitigates Ammonia-Induced Neurotoxicity by Suppressing Apoptosis, Immune Imbalance, and Gut Microbiota-Driven Metabolic Disturbance in Fattening Pigs

Ammonia could be regarded as one detrimental pollutant with an acrid smell in livestock sheds. So far, the pig breeding industry became the main source of atmospheric ammonia. Previous literature demonstrated that excessive ammonia inhalation might cause a series of physiological damage to multiple organs. Unfortunately, the toxicity mechanisms of gaseous ammonia to the porcine nervous system need further research to elucidate. Selenium (Se) involves in many essential physiological processes and has a mitigative effect on the exogenous toxicant. There were scant references that corroborated whether organic Se could intervene in the underlying toxicity of ammonia to the hypothalamus. In the present study, multi-omics tools, ethology, and molecular biological techniques were performed to clarify the detailed mechanisms of relaxation effects of L-selenomethionine on ammonia poisoning. Our results showed that ammonia inhalation caused the clinical symptoms and the increment of positive apoptosis rate in the hypothalamus with the dysfunction of mitochondrial dynamics factors, while obvious mitochondria structure defects were observed. In parallel, the inflammation medium levels and gut microbes-driven metabolism function were altered to mediate the neurotoxicity in fattening pigs through the initiation of inflammation development. Interestingly, L-selenomethionine could attenuate ammonia toxicity by activating the PI3K/Akt/PPAR-γ pathway to inhibit the mitochondria-mediated apoptosis process, blocking the abnormal immune response and the accumulation of reactive oxygen species in the nucleus. Meanwhile, Se could enhance the production performance of fattening sows. Taken together, our study verified the novel hypothesis for the toxicity identification of aerial ammonia and provided a therapeutic strategy for the treatment of occupational poisoning.

House ammonia exposure causes alterations in microbiota, transcriptome, and metabolome of rabbits

Introduction

Pollutant gas emissions in the current production system of the livestock industry have negative influences on environment as well as the health of farm staffs and animals. Although ammonia (NH3) is considered as the primary and harmful gas pollutant in the rabbit farm, less investigation has performed to determine the toxic effects of house ammonia exposure on rabbit in the commercial confined barn.

Methods

In this study, we performed multi-omics analysis on rabbits exposed to high and low concentration of house ammonia under similar environmental conditions to unravel the alterations in nasal and colonic microbiota, pulmonary and colonic gene expression, and muscular metabolic profile.

Results and discussion

The results showed that house ammonia exposure notably affected microbial structure, composition, and functional capacity in both nasal and colon, which may impact on local immune responses and inflammatory processes. Transcriptome analysis indicated that genes related to cell death (MCL1, TMBIM6, HSPB1, and CD74) and immune response (CDC42, LAMTOR5, VAMP8, and CTSB) were differentially expressed in the lung, and colonic genes associated with redox state (CAT, SELENBP1, GLUD1, and ALDH1A1) were significantly up-regulated. Several key differentially abundant metabolites such as L-glutamic acid, L-glutamine, L-ornithine, oxoglutaric acid, and isocitric acid were identified in muscle metabolome, which could denote house ammonia exposure perturbed amino acids, nucleotides, and energy metabolism. In addition, the widespread and strong inter-system interplay were uncovered in the integrative correlation network, and central features were confirmed by in vitro experiments. Our findings disclose the comprehensive evidence for the deleterious effects of house ammonia exposure on rabbit and provide valuable information for understanding the underlying impairment mechanisms.

Effects of dietary supplementation of bacteriophage cocktail on health status of weanling pigs in a non-sanitary environment

BACKGROUND

The study evaluated the effects of bacteriophage cocktail (BP) and ZnO administered during weaning time for piglets exposed to a non-sanitary environment. The bacteriophages were designed to eliminate Escherichia coli (K88, K99 and F41), Salmonella (typhimurium and enteritidis), and Clostridium perfreingens (types A and C). Forty 21-day-old crossbreed piglets were assigned to four treatments, including the PC (sanitary environment), NC (non-sanitary environment), BP (NC plus 10⁸ pfu/kg BP), and ZO (NC plus 2,500 mg/kg ZnO). Piglets in the NC, BP and ZO were kept in a non-sanitary environment for 14 d, which was contaminated with the feces of infected pigs.

RESULTS

Pigs in the BP and ZO treatments had a higher final body weight compared with the NC. The NC treatment showed the highest concentration of inflammatory cytokines including interleukin (IL)-1β, IL-6 and tumor necrosis factor-α in the plasma. The administration of BP and ZO showed lower myeloperoxidase concentrations compared with the NC. The NC treatment showed a lower concentration of superoxide dismutase in serum compared with the PC. Among the treatments in non-sanitary environment, the NC treatment showed a higher concentration of malondialdehyde compared with the ZO. The PC treatment showed a lower concentration of butyric acid in the feces compared with the BP treatment. Among non-sanitary treatments, the villus height in the duodenum was greater in the BP and ZO compared with the NC. The lower abundance of Proteobacteria phylum was observed in the BP and PC treatments compared with the NC. The highest relative abundance of Eubacterium was recorded in the BP treatment. The abundance of Megasphaera and Schwartzia was higher in the NC pigs compared with the BP piglets. The abundance of Desulfovibrio was lower in the supplemented treatments (BP and ZO) compared with non-supplemented (NC and PC). The abundance of Cellulosilyticum genera was higher in the BP and ZO treatments rather than in the NC. The piglets in the NC treatment had the highest abundance of Escherichia-Shigella, followed by the PC and ZO treatments.

CONCLUSION

In conclusion, these results suggest that the supplementation of bacteriophage cocktail could effectively control Proteobacteria phylum, Clostridium spp. and coliforms population and mitigated the adverse influences of weaning stress in piglets.

Ammonia-induced oxidative stress triggered proinflammatory response and apoptosis in pig lungs

Ammonia, a common toxic gas, is not only one of the main causes of haze, but also can enter respiratory tract and directly affect the health of humans and animals. Pig was used as an animal model for exploring the molecular mechanism and dose effect of ammonia toxicity to lung. In this study, the apoptosis of type II alveolar epithelial cells was observed in high ammonia exposure group using transmission electron microscopy. Gene and protein expression analysis using transcriptome sequencing and western blot showed that low ammonia exposure induced T-cell-involved proinflammatory response, but high ammonia exposure repressed the expression of DNA repair-related genes and affected ion transport. Moreover, high ammonia exposure significantly increased 8-hydroxy-2-deoxyguanosine (8-OHdG) level, meaning DNA oxidative damage occurred. In addition, both low and high ammonia exposure caused oxidative stress in pig lungs. Integrated analysis of transcriptome and metabolome revealed that the up-regulation of LDHB and ND2 took part in high ammonia exposure-affected pyruvate metabolism and oxidative phosphorylation progress, respectively. Inclusion, oxidative stress mediated ammonia-induced proinflammatory response and apoptosis of porcine lungs. These findings may provide new insights for understanding the ammonia toxicity to workers in livestock farms and chemical fertilizer plants.

Selenium Alleviates Ammonia-Induced Splenic Cell Apoptosis and Inflammation by Regulating the Interleukin Family/Death Receptor Axis and Nrf2 Signaling Pathway

Ammonia (NH₃) is a harmful gas in livestock houses. So far, many researchers have demonstrated that NH₃ is detrimental to animal and human organs. Selenium (Se) is one of the essential trace elements in the body and has a good antioxidant effect. However, there was little conclusive evidence that Se alleviated NH₃ poisoning. To investigate the toxic mechanism of NH₃ on pig spleen and the antagonistic effect of L-selenomethionine, a porcine NH₃-poisoning model and an L-selenomethionine intervention model were established in this study. Our results showed that NH₃ exposure increased the apoptosis rate, while L-selenomethionine supplementation alleviated the process of excessive apoptosis. Immunofluorescence staining, real-time quantitative polymerase chain reaction (qRT-PCR), and western blot results confirmed that exposure to NH₃ changed the expression levels of interleukin family factors, apoptosis, death receptor, and oxidative stress factors. Our study further confirmed that excessive NH₃ induced inflammatory response and mediated necroptosis leading to cell apoptosis by activating the Nrf2 signaling pathway. Excessive NH₃ could mediate spleen injury through oxidative stress-induced mitochondrial dynamics disorder. L-Selenomethionine could alleviate inflammation and abnormal apoptosis by inhibiting the IL-17/TNF-α/FADD axis. Our study would pave the way for comparative medicine and environmental toxicology.

Ascophyllum nodosum polysaccharide regulates gut microbiota metabolites to protect against colonic inflammation in mice

Ascophyllum nodosum polysaccharide (ANP) can protect against colonic inflammation but the underlying mechanism is still unclear. This study has determined the metabolites of gut microbiota regulated by ANP to reveal the mechanism of the anti-inflammation effect of ANP. Using an in vitro colonic fermentation model, the results indicate that gut microbiota could utilize a proportion of ANP to increase the concentrations of short-chain fatty acids (SCFAs) and decrease ammonia content. Metabolomics revealed that 46 differential metabolites, such as betaine, L-carnitine, and aminoimidazole carboxamide ribonucleotide (AICAR), could be altered by ANP. Metabolic pathway analysis showed that ANP mainly up-regulated the phenylalanine, tyrosine, and tryptophan biosynthesis and aminoacyl-tRNA biosynthesis, which were negatively correlated with inflammation progression. Interestingly, these metabolites associated with inflammation were also up-regulated by ANP in colitis mice, including betaine, L-carnitine, AICAR, N-acetyl-glutamine, tryptophan, and valine, which were mainly associated with amino acid metabolism and aminoacyl-tRNA biosynthesis. Furthermore, the metabolites modulated by ANP were associated with the relative abundances of Akkermansia, Bacteroides, Blautia, Coprobacillus, Enterobacter, and Klebsiella. Additionally, based on VIP values, betaine is a key metabolite after the ANP supplement in vitro and in vivo. As indicated by these findings, ANP can up-regulate the production of SCFAs, betaine, L-carnitine, and AICAR and aminoacyl-tRNA biosynthesis to protect against colonic inflammation and maintain intestinal health.

Functional Fermented Milk with Fruit Pulp Modulates the In Vitro Intestinal Microbiota

The effect of putative probiotic fermented milk (FM) with buriti pulp (FMB) or passion fruit pulp (FMPF) or without fruit pulp (FMC) on the microbiota of healthy humans was evaluated. FM formulations were administered into a simulator of the human intestinal microbial ecosystem (SHIME^®) to evaluate the viability of lactic acid bacteria (LAB), microbiota composition, presence of short-chain fatty acids (SCFA), and ammonium ions. The probiotic LAB viability in FM was affected by the addition of the fruit pulp. Phocaeicola was dominant in the FMPF and FMB samples; Bifidobacterium was related to FM formulations, while Alistipes was associated with FMPF and FMB, and Lactobacillus and Lacticaseibacillus were predominant in FMC. Trabulsiella was the central element in the FMC, while Mediterraneibacter was the central one in the FMPF and FMB networks. The FM formulations increased the acetic acid, and a remarkably high amount of propionic and butyric acids were detected in the FMB treatment. All FM formulations decreased the ammonium ions compared to the control; FMPF samples stood out for having lower amounts of ammonia. The probiotic FM with fruit pulp boosted the beneficial effects on the intestinal microbiota of healthy humans in addition to increasing SCFA in SHIME^® and decreasing ammonium ions, which could be related to the presence of bioactive compounds.

Gut microbiota dysbiosis exaggerates ammonia-induced tracheal injury Via TLR4 signaling pathway

Ammonia is a toxic air pollutant that causes severe respiratory tract injury in animals and humans. Gut microbiota dysbiosis has been found to be involved in the development of respiratory tract injury induced by air pollutants, however, the specific mechanism requires investigation. Here, we found that, inhaled ammonia induced tracheal injury by reducing expression of claudin-1, increasing expression of muc5ac, TLR4, MyD88, NF-κB and cytokines (TNF-α, IL-1β, IL-6 and IL-10), and also altering tracheal microbiota composition. Spearman correlation analysis indicated that gut microbiota dysbiosis positively correlated with TLR4 level in the trachea. Antibiotic depletion intestinal microbiota treatment reduced the severity of ammonia-induced tracheal injury via TLR4 signaling pathway. Microbiota transplantation induced the tracheal injury via TLR4 signaling pathway even without the ammonia exposure. These results indicate that gut microbiota dysbiosis exaggerates ammonia-induced tracheal injury via TLR4 signaling pathway. In addition, the [Ruminococcus]_torques_group, Faecalibacterium, unclassified_f_Lachnospiraceae may be the key gut microbiota contributing to the alterations of tracheal microbiota composition.

Organic Selenium Alleviates Ammonia-Mediated Abnormal Autophagy by Regulating Inflammatory Pathways and the Keap1/Nrf2 Axis in the Hypothalamus of Finishing Pigs

Ammonia is a significant pollutant in the livestock houses and the atmospheric environment, and excessive ammonia would harm the health of livestock and breeders. Previous studies have shown that ammonia exposure could damage the tissue structure of the nervous system, but the molecular mechanism of ammonia-induced hypothalamus damage was still unclear. The purpose of this study was to determine the role of excessive ammonia in abnormal autophagy of pig hypothalamus and whether selenomethionine would have a mitigating effect on ammonia toxicity. Twenty-four 18-week pigs were randomly divided into four groups: the control group (C group), the selenium group (Se group), the ammonia + selenium group (A + Se group), and the ammonia group (A group). In our study, the expression levels of NF-κB, IL-1β, iNOS, TNF-α, IKK-α, p-IKK-α, Nrf2, ATG5, ATG 10, ATG 12, LC3 I/II, HSP60, HSP70, and HSP90 were increased after ammonia exposure; meanwhile, IFN-γ, IKB-α, p-IKB-α, Keap1, P62, mTOR, AKT, p-AKT, PI3K, SQSTM, and Beclin1 showed decreasing trends. The results indicated that excessive ammonia inhalation inhibited the AKT/mTOR pathway to acclerated autophagy through oxidative stress-mediated inflammation in the porcine hypothalamus. L-selenomethionine could alleviate hypothalamus injury induced by ammonia exposure.

The use of selenomethionine to reduce ammonia toxicity in porcine spleen by inhibiting endoplasmic reticulum stress and autophagy mediated by oxidative stress

Ammonia (NH3) is a typical pollutant in the atmosphere and is well known for its harmful effects on plants, animals as well as human health. Previous studies have shown that NH3 exposure can cause damage to immune organs and impaired immune function in animals. Selenomethionine is a kind of organic selenium, which can not only promote the growth and development of the body, but also inhibit the generation of intracellular reactive oxygen species (ROS), and effectively improve the immune function of the body. Therefore, this study evaluated the toxic effect of NH3 exposure on spleen from a new perspective and investigated the protective effect of selenomethionine on ammonia-induced immunotoxicity. Twenty-four Large White*Duroc*Min pigs were randomly assigned to 4 groups: control group, NH3 group, selenium group, and NH3 + selenium group. Our results showed that NH3 inhalation caused autophagy in the pig spleen, a decrease in lymphocytes, and an increase in autophagic vesicles. Also, NH3 exposure led to a decrease in the activity of some antioxidant enzymes (decreased by about 50%) and a significant increase in the expression of genes related to oxidative stress and endoplasmic reticulum stress (ERS). Our results indicated that selenomethionine mitigated ammonia toxicity in pigs (alleviated about 20-55%). In summary, our findings should be of value in providing a theoretical basis for revealing the toxicity of the high-risk gas NH3, and providing a new perspective on the mechanism of Se against toxic substances.

Transcriptome Revealed Exposure to the Environmental Ammonia Induced Oxidative Stress and Inflammatory Injury in Spleen of Fattening Pigs

Simple Summary

Ammonia is a major environmental pollutant. Previous estimates of ammonia emissions have focused on livestock sources in agricultural systems. Livestock continues to be the main source of ammonia emissions. Exposure to high concentrations of ammonia can cause varying degrees of damage to tissues and organs. However, the damage of ammonia exposure to the spleen of pigs in the fattening pigs is unknown. Therefore, the aim of this study was to explore the mechanism at the gene level of exogenous ammonia-induced spleen toxicity by enzyme-linked immunosorbent assay (ELISA), spleen histomorphological observation, and transcriptome technology. The results showed that ammonia exposure led to oxidative stress, activation of inflammatory pathways, and splenic injury. In addition, the genes that encode histone methyltransferase were found to be significantly upregulated. Therefore, histone methylation may be the epigenetic mechanism of splenic poisoning induced by ammonia. Our findings provide a novel direction for exploring the underlying molecular mechanisms of ammonia toxicity.

Abstract

Ammonia is one of the major environmental pollutants that seriously threaten human health. Although many studies have shown that ammonia causes oxidative stress and inflammation in spleen tissue, the mechanism of action is still unclear. In this study, the ammonia poisoning model of fattening pigs was successfully established. We examined the morphological changes and antioxidant functions of fattening pig spleen after 30-day exposure to ammonia. Effects of ammonia in the fattening pig spleen were analyzed from the perspective of oxidative stress, inflammation, and histone methylation via transcriptome sequencing technology (RNA-seq) and real-time quantitative PCR validation (qRT-PCR). We obtained 340 differential expression genes (DEGs) by RNA-seq. Compared with the control group, 244 genes were significantly upregulated, and 96 genes were significantly downregulated in the ammonia gas group. Some genes in Gene Ontology (GO) terms were verified and showed significant differences by qRT-PCR. The KEGG pathway revealed significant changes in the MAPK signaling pathway, which is strongly associated with inflammatory injury. To sum up, the results indicated that ammonia induces oxidative stress in pig spleen, activates the MAPK signaling pathway, and causes spleen necrosis and injury. In addition, some differential genes encoding epigenetic factors were found, which may be involved in the response mechanism of spleen tissue oxidative damage. The present study provides a transcriptome database of ammonia-induced spleen poisoning, providing a reference for risk assessment and comparative medicine of ammonia.

Probiotic Formulations: A Patent Landscaping Using the Text Mining Approach

The outstanding research outcomes and registrations of myriads of probiotic strains have flooded the health market with various innovative probiotic-based products and their patents. The study of patented formulations of probiotics can give an overall insight into its existing application. A landscaping review of patents for probiotic-based preparations is presented in the current work. The patent search was performed over commercially available patent databased and analysis tool-PatSeer Pro®. Search strings containing words "Formulation" and "Composition" resulted in more than 3700 patents. Landscaping review of 400 + patents from the last 20 years (2000-2020) was performed using the Text-Mining approach. Text-Mining helped to identify 19 technological clusters which represent these patents. These clusters include the patents of probiotic preparations on animal feed, human food, cosmetics, antimicrobial, antidiabetic, arthritis, etc. A review of this massive number of patents unveiled many exciting preparations. Probiotic-based innovative products for depression, diabetes, Parkinson's, tumor, acne, and animal husbandry are reviewed comprehensively. The present work also unravels a few new-flanged products like probiotic layered condoms, products for acute alcoholism, and traditional Chinese medicine with probiotics. The patent landscape of probiotic-based preparations has presented a whole scenario of probiotic-based preparations. It has also revealed many unexplored areas where innovation can be excelled.

Evaluation of potential cardiotoxicity of ammonia: l-selenomethionine inhibits ammonia-induced cardiac autophagy by activating the PI3K/AKT/mTOR signaling pathway

Ammonia is a major harmful gas in the environment of livestock and poultry. Studies have shown that excessive ammonia inhalation has adverse effects in pig heart. However, the mechanism of ammonia-induced cardiac toxicity in pigs has not been reported. L-selenomethionine is a kind of organic selenium (Se) which is easily absorbed by the body. Therefore, in this study, twenty-four 125-day-old pigs were randomly divided into 4 groups: C (control) group, A (ammonia) group, Se group (Se content: 0.5 mg kg-1), and A (ammonia) + Se group. The mechanism of ammonia-induced cardiotoxicity and the alleviating effect of L-selenomethionine were examined. The results in the A group showed as follows: a large number of myocardial fiber edema and cytoplasmic bleakness were observed in the heart; a large number of mitochondrial autophagy were observed; ATP content, ATPase activities and hematological parameters decreased significantly; Endoplasmic reticulum stress (ERS) markers (GRP78, IRE1α, ATF4, ATF6, and CHOP) were significantly induced in the mRNA and protein levels; PI3K/AKT/mTOR signaling pathway was activated; and autophagy key genes and proteins (Beclin-1, LC3, ATG3, and ATG5) were significantly up-regulated. The results of comparison between the A + Se group and the A group were as follows: the degree of edema of cardiac muscle fiber in the A + Se group was somewhat relieved; the level of mitochondrial autophagy decreased; ATP content and ATPase activities increased significantly; the mRNA and protein levels of ERS markers were significantly down-regulated; the expression level of PI3K/AKT/mTOR signaling pathway was decreased; and the mRNA and protein levels of key autophagy genes were decreased. However, the changes of these indexes in the A + Se group were still significantly different from those in the C group. Our results indicated that L-selenomethionine supplementation inhibited ammonia-induced cardiac autophagy by activating the PI3K/AKT/mTOR signaling pathway, which confirmed that L-selenomethionine could alleviate the cardiac injury caused by excessive ammonia inhalation to a certain extent. This study aims to enrich the toxicological mechanism of ammonia and provide valuable reference for future intervention of ammonia toxicity.

CircRNA-IGLL1/miR-15a/RNF43 axis mediates ammonia-induced autophagy in broilers jejunum via Wnt/β-catenin pathway

With the continued increase of global ammonia emission, the damage to human or animal caused by ammonia pollution has attracted wide attention. The noncoding RNAs have been reported to regulate a variety of biological processes under different environmental stimulation via ceRNA (competing endogenous RNA) networks. Autophagy is a hallmark of tissue damage from air pollution. However, the specific role of circular RNAs (circRNAs) in the injury of intestinal tissue caused by autophagy remains unclear. Here, we established 42-days old ammonia-exposed broiler models and observed that autophagy flux in broiler jejunum was activated under ammonia exposure. Meanwhile, a total of eight significantly dysregulated expressed circRNAs were obtained and a circRNAs-miRNAs-genes interaction networks were constructed by bioinformatics analysis. Furthermore, an axis named circRNA-IGLL1/miR-15a/RNF43 was predicted to participate in the excessive autophagy by targeting RNF43. The target relationship was proved by dual-luciferase reporter assay in vitro. Mechanistically, downregulated circRNA-IGLL1 could suppress the expression of RNF43 in ammonia-exposed jejunum and the Wnt/β-catenin pathway was activated. Inhibition of miR-15a reversed autophagy caused by downregulated circRNA-IGLL1. CircRNA-IGLL1 could competitively bind miR-15a to regulate RNF43 expression, thus modulating the occurrence of autophagy. Taken together, our results showed that circRNA-IGLL1/miR-15a/RNF43 axis is involved in ammonia-induced intestinal autophagy in broilers.

Ammonia stress disrupts intestinal microbial community and amino acid metabolism of juvenile yellow catfish (Pelteobagrus fulvidraco)

Ammonia has adverse effects on aquatic animals, which is also widely distributed in natural aquatic environments and intensive aquaculture systems. The intestine is a primary defensive line for aquatic animals, the accumulation of ammonia in the aquatic environment can cause irreversible damage to intestinal function. In this study, we investigated the effects of acute ammonia stress on the reaction characteristics of digestive function, amino acid metabolism, and the variation in the intestinal microbiota of juvenile yellow catfish (Pelteobagrus fulvidraco). Thus, the yellow catfish was placed in water with the addition of ammonia at 0 (control), 14.6, and 146 mg/L total ammonia nitrogen for 96-h. The present study observed that ammonia accumulated in the intestine and muscle (ammonia contents in the intestine and muscle increased) and induced the activities of protein digestive enzymes dysfunction (pepsin increased while trypsin decreased). Ammonia stress changed various amino acids composition (proline, arginine, lysine, histidine, phenylalanine, tyrosine, leucine, isoleucine, valine, alanine, glutamic acid, tyrosine, and aspartic acid contents were increased in muscle) and increased the activities of alanine aminotransferase and aspartate aminotransferase in muscle. Furthermore, through 16 S rRNA gene analysis, ammonia stress-induced reduction in diversity, richness, and evenness and structure of microbiota alteration in the intestine. At the phylum level, the abundance of Fusobacteria increased while Firmicutes and Actinobacteria decreased significantly. At the genus level, the abundance of beneficial microbiota Cetobacterium significantly increased after ammonia stress. In conclusion, activation of amino acid synthesis in muscle may be involved in ammonia detoxification after severe ammonia stress. The accumulation of ammonia can disrupt the intestinal digestive function and intestinal microbiota community. The Cetobacterium may be a new potential positive factor in the resistance of ammonia toxicity.

Selenomethionine protects against ammonia-induced apoptosis through inhibition of endoplasmic reticulum stress in pig kidneys

Ammonia (NH₃) emission is a common threat to farm animals. Selenium (Se) is known for its antioxidant property and can resist several stressors affecting farm animals. The aims of this study were (Ⅰ) to determine how excess NH₃ exert nephrotoxic effects in pigs and (Ⅱ) to investigate whether selenomethionine has an alleviative effect on NH₃ toxicity. Two diets supplemented with different doses of Se (0.22 mg/kg or 0.50 mg/kg) and two concentrations of NH₃ (< 5 mg/m³ or 89.8 mg/m³) were used in a 2 × 2 factorial design trial for a period of 30 days. The results showed that NH₃ exposure caused apoptosis and increased the number of apoptotic cells in pig kidneys. Further, the activities of antioxidant enzymes were decreased, and the transcriptional and translational levels of endoplasmic reticulum stress-related genes, Bcl-2 and Caspase family members were increased under NH₃ exposure. In addition, Wnt/β-catenin signaling pathway was suppressed after NH₃ treatment. Dietary supplement with selenomethionine appears to offer protection against NH₃-induced kidney injury in pigs and the pathologic changes above were alleviated. Our findings provide additional insight into the mechanism of NH₃ toxicity in pigs while elucidating the role of Se as a potential antidote against NH₃ poisoning.

In-Feed Supplementation of Resin Acid-Enriched Composition Modulates Gut Microbiota, Improves Growth Performance, and Reduces Post-Weaning Diarrhea and Gut Inflammation in Piglets

The weaning process represents a delicate phase for piglets, and is often characterized by lower feed intake, lower weight gain, diarrhea, and ultimately increased mortality. We aimed to determine the effects of RAC supplementation in diets on improving piglet growth and vitality, reducing post-weaning diarrhea, and enhancing gut health. In a 2 × 2 × 2 factorial experiment, we selected forty sows and their piglets. Piglets were followed until seven weeks of age. There were no significant differences found between RAC treated and control piglets until weaning (p = 0.26). However, three weeks after weaning, RAC treated piglets had higher body weight and average daily growth (ADG) than the control piglets (p = 0.003). In addition, the piglets that received RAC after weaning, irrespective of mother or prior creep feed treatment, had lower post-weaning diarrhea (PWD) and fecal myeloperoxidase (MPO) level than control piglets. Gut microbiota analysis in post-weaning piglets revealed that RAC supplementation significantly increased Lachnospiraceae_unclassified, Blautia, Butyricicoccus, Gemmiger and Holdemanella, and decreased Bacteroidales_unclassified. Overall, RAC supplementation to piglets modulated post-weaning gut microbiota, improved growth performance after weaning, reduced post-weaning diarrhea and reduced fecal myeloperoxidase levels. We therefore consider RAC to be a potential natural feed supplement to prevent enteric infections and improve growth performance in weaning piglets.

Exposure to High Aerial Ammonia Causes Hindgut Dysbiotic Microbiota and Alterations of Microbiota-Derived Metabolites in Growing Pigs

Ammonia, an atmospheric pollutant in the air, jeopardizes immune function, and perturbs metabolism, especially lipid metabolism, in human and animals. The roles of intestinal microbiota and its metabolites in maintaining or regulating immune function and metabolism are irreplaceable. Therefore, this study aimed to investigate how aerial ammonia exposure influences hindgut microbiota and its metabolites in a pig model. Twelve growing pigs were treated with or without aerial ammonia (35 mg/m³) for 25 days, and then microbial diversity and microbiota-derived metabolites were measured. The results demonstrated a decreasing trend in leptin (p = 0.0898) and reduced high-density lipoprotein cholesterol (HDL-C, p = 0.0006) in serum after ammonia exposure. Besides, an upward trend in hyocholic acid (HCA), lithocholic acid (LCA), hyodeoxycholic acid (HDCA) (p < 0.1); a downward trend in tauro-deoxycholic acid (TDCA, p < 0.1); and a reduced tauro-HDCA (THDCA, p < 0.05) level were found in the serum bile acid (BA) profiles after ammonia exposure. Ammonia exposure notably raised microbial alpha-diversity with higher Sobs, Shannon, or ACE index in the cecum or colon and the Chao index in the cecum (p < 0.05) and clearly exhibited a distinct microbial cluster in hindgut indicated by principal coordinate analysis (p < 0.01), indicating that ammonia exposure induced alterations of microbial community structure and composition in the hindgut. Further analysis displayed that ammonia exposure increased the number of potentially harmful bacteria, such as Negativibacillus, Alloprevotella, or Lachnospira, and decreased the number of beneficial bacteria, such as Akkermansia or Clostridium_sensu_stricto_1, in the hindgut (FDR < 0.05). Analysis of microbiota-derived metabolites in the hindgut showed that ammonia exposure increased acetate and decreased isobutyrate or isovalerate in the cecum or colon, respectively (p < 0.05). Unlike the alteration of serum BA profiles, cecal BA data showed that high ammonia exposure had a downward trend in cholic acid (CA), HCA, and LCA (p < 0.1); a downward trend in deoxycholic acid (DCA) and HDCA (p < 0.05); and an upward trend in glycol-chenodeoxycholic acid (GCDCA, p < 0.05). Mantel test and correlation analysis revealed associations between microbiota-derived metabolites and ammonia exposure-responsive cecal bacteria. Collectively, the findings illustrated that high ammonia exposure induced the dysbiotic microbiota in the hindgut, thereby affecting the production of microbiota-derived short-chain fatty acids and BAs, which play a pivotal role in the modulation of host systematic metabolism.

Effects of Ammonia on Gut Microbiota and Growth Performance of Broiler Chickens

Simple Summary

The composition and function of gut microbiota is crucial for the health of the host and closely related to animal growth performance. Factors that impact microbiota composition can also impact its productivity. Ammonia (NH3), one of the major contaminants in poultry houses, negatively affects poultry performance. However, the influence of ammonia on broiler intestinal microflora, and whether this influence is related to growth performance, has not been reported. Our results indicated that ammonia caused changes to cecal microflora of broilers, and these changes related to growth performance. Understanding the effects of ammonia on the intestinal microflora of broilers will be beneficial in making targeted decisions to minimize the negative effects of ammonia on broilers.

Abstract

In order to investigate the influence of ammonia on broiler intestinal microflora and growth performance of broiler chickens, 288 21-day-old male Arbor Acres broilers with a similar weight were randomly divided into four groups with different NH3 levels: 0 ppm, 15 ppm, 25 ppm, and 35 ppm. The growth performance of each group was recorded and analyzed. Additionally, 16s rRNA sequencing was performed on the cecal contents of the 0 ppm group and the 35 ppm group broilers. The results showed the following: a decrease in growth performance in broilers was observed after 35 ppm ammonia exposure for 7 days and 25 ppm ammonia exposure for 14 days. At phylum level, the relative abundance of Proteobacteria phylum was increased after 35 ppm ammonia exposure. At genus level, ammonia increased the relative abundance of Escherichia–Shigella and decreased the relative abundance of Butyricicoccus, Parasutterella, Lachnospiraceae_UCG-010, Ruminococcaceae_UCG-013 and Ruminococcaceae_UCG-004. Negative correlation between Escherichia–Shigella and growth performance, and positive correlation between bacteria genera (including Butyricicoccus, Parasutterella, Lachnospiraceae_UCG-010, Ruminococcaceae_UCG-013 and Ruminococcaceae_UCG-004) and growth performance was observed. In conclusion, ammonia exposure caused changes in the structure of cecal microflora, and several species were either positively or negatively correlated with growth performance. These findings will help enhance our understanding of the possible mechanism by which ammonia affect the growth of broilers.