Proteome changes in the small intestinal mucosa of broilers (Gallus gallus) induced by high concentrations of atmospheric ammonia

Alteration of growth performance and characterization of pathological lesions in long-term ammonia-exposed pigs

Ammonia (NH3) is a major cause of odor emissions from swine farms, and exposure to high concentrations of NH3 in short-term periods has been reported to cause respiratory and systemic disorders in pigs. However, the impact of long-term NH3 exposure on pig health and productivity remain unknown. This study aimed to assess the impact of long-term NH3 exposure on growth performance and pathological outcomes in pigs. Pigs were reared in the treatment room [34.8 mg/m3 NH3 concentration (50 ppm); TRT group, n = 40] and the control room [5.6 mg/m3 (8 ppm); CON, n = 40]. The experimental period was 107 days (from weaning piglets to market age). Our findings revealed that long-term NH3 exposure results in severe respiratory and systemic pathological lesions, including chronic tracheitis, epithelial metaplasia of the trachea, severe interstitial pneumonia, myocarditis, and interstitial nephritis. In addition, the TRT group exhibited reduced productivity, with two deaths, indicating that uncontrolled NH3 concentrations on pig farms could be linked to a decline in growth performance and even death. Transcriptomic analysis revealed significant changes in immune and inflammatory pathways in lung from TRT pigs, including dysregulated cytokine signaling and incomplete inflammatory responses. The enrichment of DEGs in pathways, such as Cytokine-cytokine receptor interaction, JAK-STAT, and Toll-like receptor signaling, indicated chronic NH3 exposure disrupted immune homeostasis, contributing to chronic inflammation and impaired tissue repair. In conclusion, this study provides valuable insights into the detrimental effects of NH3 exposure on pig health and productivity under farm conditions.

Involvement of glyphosate in disruption of biotransformation P450 enzymes and hepatic lipid metabolism in chicken

The current study investigated the potentially harmful consequences of pure glyphosate or Roundup® on CYP family members and lipid metabolism in newly hatched chicks. On the sixth day, 225 fertilized eggs were randomly divided into three treatments: (1) the control group injected with deionized water, (2) the glyphosate group injected with 10 mg pure glyphosate/Kg egg mass and (3) the Roundup group injected 10 mg the active ingredient glyphosate in Roundup®/Kg egg. The results of the study revealed a reduction in hatchability in chicks treated with Roundup®. Moreover, change of Lipid concentration in serum and the liver-treated groups. Additionally, increased liver function enzymes and increased oxidative stress in the glyphosate and Roundup® groups. Furthermore, liver tissues showed histological changes and several lipid deposits in glyphosate-treated groups. Hepatic CYP1A2 and CYP1A4 expressions were significantly increased (p < .05) after glyphosate exposure, and suppression of CYP1C1 mRNA expression was significant (p < .05) after Roundup® exposure. The pro-inflammatory cytokines genes IFN-γ and IL-1β expression were significantly increased (p < .05) after Roundup® exposure. In addition, there were significant differences in the levels of expression genes which are related to lipid synthesis or catabolism in the liver. In conclusion, in ovo glyphosate exposure caused disruption of biotransformation, pro-inflammatory and lipid metabolism in chicks.

Melatonin alleviates 3,3',4,4',5-pentachlorobenzene induced colon injury by relieving oxidative stress

3,3',4,4',5-pentachlorobiphenyl (PCB126) is widely distributed, non-degradable and bioaccumulative, which can affect the function of tissues and organs of the living organisms. Melatonin (MT) is a sort of indole neurohormone that is mainly secreted by the pineal gland. Numerous studies have shown that MT can alleviate intestinal injury through various mechanisms such as antioxidant, anti-inflammatory, and anti-apoptosis. For the above reasons, the aim of this study is to explore the mechanism of intestinal injury in mice after exposure to PCB126 as well as the antagonistic effect of MT. Mice were respectively fed PCB126 (0.326 mg/kg) and/or MT (10 mg/kg) in vivo. In vitro, colonic epithelial cells (MCEC) were treated with PCB126 (150 μM) and/or MT (2 mM). We found that the microscopic structure of colon tissue was impaired after exposure to PCB126. The levels of oxidative stress, the protein and mRNA levels of expression of inflammatory related factors were significantly increased and the expression levels of intestinal tight junction protein were decreased. Notably, MT can promote Nrf2/HO-1 expression level and reduce the colonic injury caused by PCB126. Further in vitro treatment with reactive oxygen species inhibitors (NAC) showed that it significantly alleviated PCB126-induced in MCEC cell damage. In summary, the above results suggested that MT alleviates PCB126-induced colon inflammation by inhibiting the overproduction of reactive oxygen species (ROS) and up-regulating the expression level of intestinal tight junction protein. Our results contribute to the further comprehension of the intestinal toxicity effects of PCB126 and the significant role of MT in preserving the mechanisms of intestinal injury.

Monitoring physiological processes of fast-growing broilers during the whole life cycle: Changes of redox-homeostasis effected to trassulfuration pathway predicting the development of non-alcoholic fatty liver disease

In the broiler industry, the average daily gain and feed conversion ratio are extremely favorable, but the birds are beginning to approach the maximum of their genetic capacity. However, as a consequence of strong genetic selection, the occurrence of certain metabolic diseases, such as myopathies, ascites, sudden cardiac death and tibial dyschondroplasia, is increasing. These metabolic diseases can greatly affect the health status and welfare of birds, as well as the quality of meat. The main goal of this study was to investigate the changes in the main parameters of redox homeostasis during the rearing (1-42 days of age) of broilers with high genetic capacity, such as the concentrations of malondialdehyde, vitamin C, vitamin E, and reduced glutathione, the activities of glutathione peroxidase and glutathione reductase, and the inhibition rate of superoxide dismutase. Damage to the transsulfuration pathway during growth and the reason for changes in the level of homocysteine were investigated. Further, the parameters that can characterize the biochemical changes occurring in the birds were examined. Our study is the first characterize plasma albumin saturation. A method was developed to measure the levels of other small molecule thiol components of plasma. Changes in redox homeostasis induce increases in the concentrations of tumor necrosis factor alpha and inflammatory interleukins interleukin 2, interleukin 6 and interleukin 8 in broilers reared according to current large-scale husbandry technology and feeding protocols. A significant difference in all parameters tested was observed on the 21st day. The concentrations of cytokines and homocysteine increased, while the concentrations of glutathione and cysteine in the plasma decreased. Our findings suggest that observed changes in the abovementioned biochemical indices have a negative effect on poultry health.

Mechanistic Approaches to the Application of Nano-Zinc in the Poultry and Biomedical Industries: A Comprehensive Review of Future Perspectives and Challenges

Bio-fortification is a new, viable, cost-effective, and long-term method of administering crucial minerals to a populace with limited exposure to diversified foods and other nutritional regimens. Nanotechnology entities aid in the improvement of traditional nutraceutical absorption, digestibility, and bio-availability. Nano-applications are employed in poultry systems utilizing readily accessible instruments and processes that have no negative impact on animal health and welfare. Nanotechnology is a sophisticated innovation in the realm of biomedical engineering that is used to diagnose and cure various poultry ailments. In the 21st century, zinc nanoparticles had received a lot of considerable interest due to their unusual features. ZnO NPs exhibit antibacterial properties; however, the qualities of nanoparticles (NPs) vary with their size and structure, rendering them adaptable to diverse uses. ZnO NPs have shown remarkable promise in bio-imaging and drug delivery due to their high bio-compatibility. The green synthesized nanoparticles have robust biological activities and are used in a variety of biological applications across industries. The current review also discusses the formulation and recent advancements of zinc oxide nanoparticles from plant sources (such as leaves, stems, bark, roots, rhizomes, fruits, flowers, and seeds) and their anti-cancerous activities, activities in wound healing, and drug delivery, followed by a detailed discussion of their mechanisms of action.

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.

Role of Physiology, Immunity, Microbiota, and Infectious Diseases in the Gut Health of Poultry

“Gut health” refers to the physical state and physiological function of the gastrointestinal tract and in the livestock system; this topic is often focused on the complex interacting components of the intestinal system that influence animal growth performance and host-microbial homeostasis. Regardless, there is an increasing need to better understand the complexity of the intestinal system and the various factors that influence gut health, since the intestine is the largest immune and neuroendocrine organ that interacts with the most complex microbiome population. As we face the post-antibiotic growth promoters (AGP) era in many countries of the world, livestock need more options to deal with food security, food safety, and antibiotic resilience to maintain agricultural sustainability to feed the increasing human population. Furthermore, developing novel antibiotic alternative strategies needs a comprehensive understanding of how this complex system maintains homeostasis as we face unpredictable changes in external factors like antibiotic-resistant microbes, farming practices, climate changes, and consumers’ preferences for food. In this review, we attempt to assemble and summarize all the relevant information on chicken gut health to provide deeper insights into various aspects of gut health. Due to the broad and complex nature of the concept of “gut health”, we have highlighted the most pertinent factors related to the field performance of broiler chickens.

Ammonia exposure causes the imbalance of the gut-brain axis by altering gene networks associated with oxidative metabolism, inflammation and apoptosis

Ammonia is an acknowledged environment pollutant in atmosphere with irritating smell. Previous studies have shown that excessive ammonia has toxic effects on farm animals and humans. However, the detail toxicity mechanism of ammonia to pigs is still unknown so far. In order to clarify the mechanism of ammonia toxicity, we established a porcine exogenous ammonia poisoning model and assessed the effects of ammonia on the gut-brain axis by transcriptome sequencing, histological observation and chemical analysis. Our results showed that after 30 d of ammonia exposure, 578 differentially expressed genes (DEGs) and 407 DEGs were obtained in the hypothalamus and jejunum, respectively. These DEGs were enriched into Gene Ontology terms associated with inflammation, oxidative metabolism, apoptosis, and the highly expressed genes among these DEGs were verified by real-time quantitative PCR. The content of glutathione and the activities of glutathione peroxidase and superoxide dismutase were significantly decreased, while malondialdehyde content was increased after ammonia exposure. Corticotropin releasing factor, substance P, 5-hydroxytryptamine and ghrelin contents in serum elevated significantly. Furthermore, pathologic observation in the ammonia group revealed infiltration of lymphocytes in the hypothalamus and significant decrease of jejunal epithelial cells. Our results indicated that ammonia exposure mediated changes in transcriptional profiles, pathological damage, oxidative stress and brain-gut peptide of the pig jejunum and hypothalamus, and induced the imbalance of the brain-gut axis through the "oxidative stress-inflammation-apoptosis" interaction network. Our study not only provides a new perspective for the toxicity assessment of ammonia, but also enriches the toxicology mechanism of ammonia.

Immunosuppression, oxidative stress, and apoptosis in pig kidney caused by ammonia: Application of transcriptome analysis in risk assessment of ammonia exposure

Ammonia (NH₃) is a recognized environmental contaminant around the world and has adverse effects on animal and human health. However, the mechanism of the renal toxicity of NH₃ is not well understood. Pigs are considered an ideal model for biomedical and toxicological research because of the similarity to humans in physiological and biochemical basis. Therefore, in this study, twelve pigs were selected as research objects and randomly divided into two groups, namely the control group and the NH₃ group. The formal experiment lasted 30 days. The effects of excessive NH₃ inhalation on the kidney of fattening pig were evaluated by chemical analysis, ELISA, transcriptome analysis and real-time quantitative PCR (qRT-PCR) from the renal antioxidant level, renal function, blood ammonia content and gene level. Our results showed that excessive NH₃ exposure could cause an increase in blood NH₃ content, a reduction in renal GSH-Px, SOD and GSH, as well as an increase in MDA levels and an increase in serum creatinine, urea and uric acid levels. In addition, transcriptome analysis showed that NH₃ exposure caused changes in 335 differentially expressed genes (DEGs) (including 126 up-regulated DEGs and 109 down-regulated DEGs). Some highly expressed DEGs were enriched into GO terms associated with immune function, oxidative stress, and apoptosis and were verified by qRT-PCR. The qRT-PCR results were comsistent with the transcriptome results. Our results indicated that NH₃ exposure could cause changes in renal transcriptional profiles and kidney function, and induce kidney damage in the fattening pigs through oxidative stress, immune dysfunction and apoptosis. Our present study provides novel insights into the immunotoxicity mechanism of NH₃ on kidney.

Applied Proteomics in 'One Health'

‘One Health’ summarises the idea that human health and animal health are interdependent and bound to the health of ecosystems. The purpose of proteomics methodologies and studies is to determine proteins present in samples of interest and to quantify changes in protein expression during pathological conditions. The objectives of this paper are to review the application of proteomics technologies within the One Health concept and to appraise their role in the elucidation of diseases and situations relevant to One Health. The paper develops in three sections. Proteomics Applications in Zoonotic Infections part discusses proteomics applications in zoonotic infections and explores the use of proteomics for studying pathogenetic pathways, transmission dynamics, diagnostic biomarkers and novel vaccines in prion, viral, bacterial, protozoan and metazoan zoonotic infections. Proteomics Applications in Antibiotic Resistance part discusses proteomics applications in mechanisms of resistance development and discovery of novel treatments for antibiotic resistance. Proteomics Applications in Food Safety part discusses the detection of allergens, exposure of adulteration, identification of pathogens and toxins, study of product traits and characterisation of proteins in food safety. Sensitive analysis of proteins, including low-abundant ones in complex biological samples, will be achieved in the future, thus enabling implementation of targeted proteomics in clinical settings, shedding light on biomarker research and promoting the One Health concept.

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.

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

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

Protective effect of dietary supplementation of Bupleurum falcatum L saikosaponins on ammonia exposure-induced ileum injury in broilers

Ammonia (NH3) at a high concentration has been recognized as a highly poisonous pollutant affecting both air and water quality. NH3, as a stimulus, exerts negative impact on broiler growth and production, but the molecular mechanisms are not clear yet. This study was designed to evaluate the effects of dietary supplementation of Bupleurum falcatum L saikosaponins (SP) on the growth and ileum health status in broilers exposed to NH3. Day-old Arbor Acers broilers (n = 480) were randomly allocated into 1 of 4 treatments. The main factors were dietary SP supplementation (0 or 80 mg/kg of diet) and NH3 challenge (with or without 70 ± 5 ppm NH3). The data of growth, intestinal morphology, and mRNA expression related to ileal function were collected from broilers exposed to NH3 for 7 d. Results showed that NH3 remarkably suppressed growth performance and intestinal development as well as induced biological injuries in the ileum of broilers, resulting from oxidative stress, mucous barrier damage, and immune dysfunction as well as upregulated apoptosis. These negative effects of NH3 were alleviated by the SP supplement. In conclusion, dietary supplementation of SP may be helpful in alleviating the detrimental effects of NH3 on the ileum development in broilers.

Short-Term Aerial Pollutant Concentrations in a Southwestern China Pig-Fattening House

Concentrations of critical aerial pollutants within animal farms are important to the health of animals and farm staff and can be reduced via manure management, ventilation control, and barn design. This study characterized measurements of ammonia (NH3), total suspended particle (TSP), and airborne microbial communities of a large-scale pig-fattening house, as well as their correlations with environmental variables in Southwestern China. Monitoring was conducted for 15 consecutive days during both August and January, at various locations inside the pig house. The concentrations of NH3 and TSP averaged 3.22 and 0.55 mg m−3, respectively, while the average number of airborne microbial colonies was 3.91 log cfu m−3. The aerial pollutant concentrations displayed significant seasonal differences (p < 0.05). Specifically, concentrations in winter were significantly higher than those in summer (p < 0.05), and the 07:00 measurements were the highest among the three measurement times. The concentrations were significantly correlated with indoor temperature and relative humidity. In summer, TSP concentration was negatively correlated with temperature (correlation coefficient = −0.732), while NH3 concentration was positively correlated with temperature (correlation coefficient = 0.58). In winter, TSP and NH3 concentrations were negatively correlated with relative humidity (correlation coefficients = −0.739 and −0.713, respectively), while the airborne microbial colonies were not correlated with either humidity or temperature in summer or winter. These findings confirm that the aerial pollutant concentrations in a Southwestern China pig-fattening house exhibited significant seasonal and diurnal variations. Air quality can be improved by more precise ventilation control as observed by the correlation of concentrations with ventilation control, indoor temperature, and humidity.

PTEN/AKT/mTOR pathway involvement in autophagy, mediated by miR-99a-3p and energy metabolism in ammonia-exposed chicken bursal lymphocytes

Emission of atmospheric ammonia (NH₃) is an environmental challenge because of its harmful effects on humans and animals including birds. Among all organisms, NH₃ is highly sensitive to birds. Autophagy plays a critical role in Bursa of fabricius (BF)-mediated immune responses against various hazardous substances. Therefore, we designed our work to demonstrate whether NH₃ can induce autophagy in broiler chicken BF. In this study, the downregulated levels of mammalian target of rapamycin and light chain-3 (LC-Ⅰ), as well as the upregulated levels of phosphate and tensin homology (PTEN), protein kinase B (AKT), autophagy related-5, light chain-3 (LC3-Ⅱ), Becline-1, and Dynein, were found. Our results of transmission electron microscopy displayed signs of autophagosomes/autophagic lysosomes, and immunofluorescence assay displayed that NH₃ exposure reduced the relative amount of CD8⁺ B-lymphocyte in chicken BF. Exposure of NH₃ led to energy metabolism disturbance by decreasing mRNA levels of glucose metabolism factors aconitase-2, hexokinase-1, hexokinase-2, lactate dehydrogenase-A, lactate dehydrogenase-B, pyruvate kinase, phosphofructokinase and succinate dehydrogenase complex unit-B, and adenosine triphosphates (ATPase) activities (Na⁺/K⁺ ATPase, Ca²⁺ ATPase, Mg²⁺ ATPase, and Ca/Mg²⁺ ATPase). Moreover, phosphate and tensin homology was found as target gene of microRNA-99a-3p which confirmed that high concentration of NH₃ caused autophagy in chicken BF. In summary, these findings suggested that ammonia induced autophagy via miR-99a-3p, the reduction of ATPase activity, and the alteration of autophagy-related factors, and energy metabolism mediation in BF. Our findings provide information to assess the harmful effects of NH₃ on chicken and clues for human health pathophysiology.

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.

Ammonia-triggered apoptosis via immune function and metabolic process in the thymuses of chickens by proteomics analysis

Ammonia (NH₃), an environmental pollutant with a pungent odor, is not only an important volatile in fertilizer production and ranching, but also main basic component of haze. In present study, we found that ultrastructural changes and 3167 differentially expressed proteins (DEPs) using proteomics analysis in the thymuses of chickens exposed to NH₃ on day 42. Obtained DEPs were enriched using GO and KEGG; and 66 DEPs took part in immune function, metabolic process, and apoptosis in the thymuses of chickens treated with NH₃. 9 genes of DEPs were validated using qRT-PCR, and mRNA expression of 2 immune-related genes (CTSG and NFATC2), 3 metabolic process-related genes (APOA1, GOT1, and GOLGA3), and 4 apoptosis-related genes (PIK3CD, CTSS, CAMP, and NSD2) were consistent with DEPs in chicken thymuses. Our results indicated that excess NH₃ led to immunosuppression, metabolic disorder, and apoptosis in chicken thymuses. Present study gives a novel insight into the mechanism of NH₃ toxicity and demonstrated that immune response, metabolism process, and apoptosis were important in the mechanism of NH₃ toxicity of chicken exposure to high concentration of NH₃.

Environmental contaminant ammonia triggers epithelial-to-mesenchymal transition-mediated jejunal fibrosis with the disassembly of epithelial cell-cell contacts in chicken

Ammonia (NH₃) is an environmental contaminant that is causing increasing problems with human and animal health due to the development of poultry industry. There are limited studies on the effect of NH₃ inhalation toxicity on the intestinal tract of animals, and underlying molecular mechanisms remain unclear. In the present study, we established a chicken model of NH₃ aspiration-induced injury for 42 days and observed histopathological changes of the jejunum. Tandem mass tag-based quantitative proteomic analysis was applied to investigate changes in the protein profile in the jejunum tissue of chickens that were exposed to NH₃. Overall, 48 significantly differentially expressed proteins (DEPs) were identified. GO and KEGG analyses revealed that most DEPs were closely related to epithelial-to-mesenchymal transition (EMT), cell-cell junctions, and fibrosis-related factors. Regarding fibrosis, type I collagen and fibronectin were significantly increased. With respect to EMT, epithelial marker proteins (such as E-cadherin and keratin) were repressed, while mesenchymal marker proteins (such as vimentin) were activated. Loss of epithelial cell-cell junctions (such as tight junctions, adherens junctions and desmosomes) were observed. Additionally, overexpression of transforming growth factor-beta (TGF-β) may play a key role in the EMT process and fibrosis. Taken together, these findings suggested that NH₃ triggered the EMT and disassembly of epithelial cell-cell contacts, resulting in jejunal fibrosis that was mediated by TGF-β in chickens. The results of our study will contribute to provide a technical reference regarding the research methods of intestinal toxicity of NH₃ and have largely regulatory implications for ecological risk assessment of human health.

Ammonia Exposure Induced Cilia Dysfunction of Nasal Mucosa in the Piglets

As one of the main environmental stressors commonly found in closed pig houses, ammonia poses high risks to the well-being of humans and animals. This study is aimed at assessing the toxicity of ammonia exposure (80 ppm for 12 days) on the nasal mucosa in piglets. Firstly, we found that after ammonia exposure, the number of white blood cells significantly increased and the serum levels of cytokine IL-4 were significantly decreased. Then, histological analyses showed significant thickening of nasal mucosa and excessive mucus production in the exposure group. Finally, RNA-seq analyses demonstrated that the ammonia exposure disturbed the transcriptome of nasal mucosa which revealed 176 upregulated genes and 426 downregulated genes. GO and KEGG pathway enrichment analysis of the DEGs showed that the upregulated genes were mainly related to neutrophil chemotaxis and immune response, while 80 out of the 426 downregulated genes including CCDCs, CFAPs, DNAHs, and TEKTs were enriched in the microtubule cytoskeleton and cilium morphogenesis/movement. All these results indicated that ammonia exposure induces nasal mucosal hyperplasia and cilia dysfunction, as well as a systemic inflammatory response in piglets. These findings provide new evidence for understanding the damage mechanism of ammonia on the nasal mucosa.

Disruption of cytochrome P450 enzymes in the liver and small intestine in chicken embryos in ovo exposed to glyphosate

Glyphosate is the active component of several commercial formulations as in Roundup®. The present study was investigated the toxic effects of pure glyphosate or Roundup® on the liver and small intestine of chick embryos. On day 6, a total of 180 fertile eggs injected with deionized water (control group), 10 mg pure glyphosate, or 10 mg of the active ingredient glyphosate in Roundup®/kg egg mass. The results showed an increase in relative weights of the liver in embryos that treated with Roundup®. Furthermore, oxidative stress was observed in the embryos treated with glyphosate or Roundup®, increased total superoxide dismutase, and content of malondialdehyde in the liver and intestine; moreover, decrease of glutathione peroxidase in the liver with increased in the intestine compared with the control. Besides, glutamic-pyruvic transaminase was increased in Roundup® group compared with other groups. Moreover, histopathological alterations in the liver and intestine tissues were observed in treated groups. Suppression of hepatic CYP1A2, CYP1A4, CYP1B1, and MDR1 mRNA expression after exposed to Roundup®. Furthermore, inhibition of CYP1A4 in the duodenum, CYP1A4, and MRP2 in the jejunum in embryos exposed to glyphosate or Roundup®. In addition, glyphosate treatment caused an increase of CYP3A5, CYP1C1, and IFNY mRNA expression in the jejunum and CYP1A2 expression in the ileum, while IFN-Y gene increase in embryos treated with Roundup®. In conclusion, in ovo exposure to glyphosate caused histopathological alterations and induced oxidative stress in the liver and small intestines. Moreover, the expression of cytochrome P450, MDR1, and MRP2 transporters was also modulated in the liver and small intestines for chick embryos.

Effects of ammonia exposure on growth performance and cytokines in the serum, trachea, and ileum of broilers

This study investigated the effects of ammonia (NH₃) exposure (0, 15, 25, and 35 ppm) on growth performance and cytokines in the serum, trachea, and ileum of broilers. A total of 288 22-day-old male broiler chickens were assigned to 4 treatment groups with 6 replicates of 12 chickens for a 21-D trial period. Growth performance and cytokines (IL-1β, IL-6, and IL-10) concentrations in the serum, trachea, and ileum were measured in response to 3, 7, 14, or 21 D of exposure to NH₃. Correlations between cytokines in the serum, trachea, and ileum and growth performance, and between tracheal and ileal cytokines, were also analyzed. Results showed that exposure to 15 ppm NH₃ did not influence the growth performance, but exposure to both 25 ppm and 35 ppm NH₃ decreased the growth performance compared to that of the control group. Exposure to 15 ppm NH₃ for 3 D increased IL-6 concentrations and induced an inflammatory response in the trachea and ileum, whereas exposure to 15 ppm NH₃ for 7 D increased IL-10 concentrations and induced an anti-inflammatory response in the ileum. Exposure to 25 ppm NH₃ induced an inflammatory response in the serum, trachea, and ileum after 3 D and induced an anti-inflammatory response in the ileum after 7 D. Exposure to 35 ppm NH₃ for 3 D induced both inflammatory and anti-inflammatory responses in the trachea and ileum. Furthermore, increases in cytokines in the serum, trachea, or ileum were accompanied by a decrease in BW, ADFI, ADG, and an increase of feed/gain (F/G) from 7 D to 21 D. In addition, tracheal cytokine, especially IL-1β, was positively correlated with ileal cytokine IL-1β. These results indicated that the low growth performance associated with NH₃ exposure may be due in part to an increase in cytokines, and the inflammatory response in the trachea and ileum may be related to cross-talk by cytokines such as IL-6, IL-10, and, in particular, IL-1β.

Ammonia regulates chicken tracheal cell necroptosis via the LncRNA-107053293/MiR-148a-3p/FAF1 axis

Ammonia (NH₃) is a known harmful gas that causes injury to the respiratory system. Ammonia also exists in haze, forming secondary organic aerosols. However, the specific damage caused by NH₃ in chicken trachea has not been determined. The regulatory mechanism of ceRNA and its multiple roles have been proposed in many pathomechanisms; therefore, we investigated the functional role of ceRNA in chicken trachea after NH₃ inhalation. Broiler chicken trachea exposed to NH₃ was selected as the research object. The pathological ultrastructure was observed by transmission electron microscopy. Transcriptome analyses were applied and referenced, and lncRNA-107053293 and miR-148a-3p and FAF1 were selected. A dual-luciferase reporter assay verified the target relationship. Real-time quantitative PCR (RT-PCR) and western blotting were performed to examine the expression levels of necroptosis genes, such as RIPK1, RIPK3, MLKL, caspase 8, and FADD. Our results indicated that lncRNA-107053293 regulated necroptosis by acting as a competing endogenous RNA of miR-148a-3p. FAF1, as a gene target of miR-148a-3p, also affects necroptosis.

Impact of in ovo administered pioneer colonizers on intestinal proteome on day of hatch

Pioneer colonization of the gastrointestinal tract (GIT) by bacteria is thought to have major influence on neonatal tissue development. Previous studies have shown in ovo inoculation of embryos with saline (S), species of Citrobacter (C, C2), or lactic acid bacteria (L) resulted in an altered microbiome on day of the hatch (DOH). The present study investigated GIT proteomic changes at DOH in relation to different inoculations. Embryos were inoculated in ovo with S or ∼10² cfu of C, C2, or L at 18 embryonic days. On DOH, the GIT was collected, and tissue proteins were extracted for analysis via tandem mass spectrometry. A total of 493 proteins were identified for differential comparison with S at P ≤ 0.10. Different levels were noted in 107, 39, and 78 proteins in C, C2, and L groups, respectively, which were uploaded to Ingenuity Pathway Analysis to determine canonical pathways and biological functions related to these changes. Three members of the cytokine family (interleukin [IL]-1β, IL6, and Oncostatin M) were predicted to be activated in C2, indicated with Z-score ≥ 1.50, which suggested an overall proinflammatory GIT condition. This was consistent with the activation of the acute-phase response signaling pathway seen exclusively in C2 (Z-score = 2.00, P < 0.01). However, activation (Z-score = 2.00) of IL-13, upregulation of peroxiredoxin-1 and superoxide dismutase 1, in addition to activation of nitric oxide signaling in the cardiovascular system of the L treatment may predict a state of increased antioxidant capacity and decreased inflammatory status. The nuclear factor erythroid 2-related factor 2 (NRF2)-mediated oxidative stress response (Z-score = 2.00, P < 0.01) was predicted to be upregulated in C which suggested that chicks were in an inflammatory state and associated oxidative stress, but the impact of these pathways differed from that of C2. These changes in the proteome suggest that pioneer colonizing microbiota may have a strong impact on pathways associated with GIT immune and cellular development.

Evaluation of the impact of in ovo administered bacteria on microbiome of chicks through 10 days of age

Initial inoculation and colonization of the chicken gastrointestinal tract (GIT) by microbiota have been suggested to have a major influence on the growth performance and health of birds. Commercial practices in chicken production may alter or delay microbial colonization by pioneer colonizing bacteria that can have an impact on the development and maturation of the GIT and intestinal microflora. The objective of this study was to compare the impact of apathogenic Gram-negative isolates or lactic acid bacteria (LAB) as pioneer colonizers on the microbiome at the day of hatch (DOH) and evaluate the influence through 10 D of age on ceca. At 18 embryonic days (E), the amnion of embryos was inoculated with either saline (S), approximately 102 CFU of LAB (L), Citrobacter freundii (C), or Citrobacter species (C2). Once DNA was isolated from mucosal and digesta contents, samples underwent 2 × 300 paired-end Illumina MiSeq library preparation for microbiome analysis. An increased abundance of Lactobacillaceae family and Lactobacillus genus was observed in the L group at DOH (P < 0.05), whereas the abundance of Enterococcaceae and Enterococcus was numerically decreased. While Lactobacillus salivarius was one of the pioneer colonizers in the L group at 18E, the population decreased by 10 D (39.59 to 0.09%) and replaced with a population of undefined Lactobacillus (10.36%) and Lactobacillus reuteri (3.63%). Results suggest that L treatment may have accelerated a mature microbiota. Enterobacteriaceae was the dominant family (57.44%) in C group at DOH (P < 0.05). The C2 group only showed some abundance of the C2 species (7.92%) at DOH but had the highest overall abundance of undefined Lactobacillus in the ceca by 10 D (25.28%). Taken together, different isolates provided in ovo can have an impact on the initial microbiome of the GIT, and some of these differences in ceca remain notable at 10 D.

miR-187-5p/apaf-1 axis was involved in oxidative stress-mediated apoptosis caused by ammonia via mitochondrial pathway in chicken livers

Ammonia (NH₃), a toxic gas, is an important cause of atmospheric haze and one of the main pollutants in air environment of poultry houses, threatening the health of human beings and poultry. However, little is known about the effect of NH₃ on liver apoptotic damage. This study aimed to investigate the mechanism of oxidative stress-mediated apoptosis caused by NH₃ in chicken livers and whether miR-187-5p/apaf-1 axis was involved in this mechanism. Here we duplicated NH₃ poisoning model of chickens for fattening to study the ultrastructure of chicken livers, apoptosis rate, oxidative stress indexes, miR-187-5p, and apoptosis-related genes. Obvious apoptotic characteristics of liver tissues exposed to excess NH₃ were observed, and the apoptosis rate increased. Excess NH₃ decreased the activities of catalase (CAT), superoxide dismutase (SOD), total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-Px), and increased the content of malondialdehyde (MDA), suggesting that oxidative stress occurred. miR-187-5p decreased, and apoptotic protease activating factor-1 (apaf-1) increased, indicating that excess NH₃ dysregulated miR-187-5p/apaf-1 axis. The expression of tumor protein p53 (p53), Bcl-2 associated X protein (Bax), Bcl-2 homologous antagonist/killer (Bak), Cytochrome-c (Cyt-c), Caspase-9, Caspase-8, and Caspase-3 was promoted, and the expression of B-cell lymphoma-2 (Bcl-2) was inhibited, resulting in apoptosis. Moreover, oxidative stress indexes, miR-187-5p, and apoptosis-related genes changed in dose- and time-dependent manner. Altogether, miR-187-5p/apaf-1 axis participated in oxidative stress-mediated apoptosis caused by NH₃ via mitochondrial pathway in the livers of chickens for fattening. This study may provide new ideas to study the mechanism of liver apoptotic damage induced by NH₃ exposure.

Physiological impact on layer chickens fed corn distiller's dried grains with solubles naturally contaminated with deoxynivalenol

Objective

An experiment was conducted to investigate the response of laying hens fed corn distiller’s dried grains with solubles (DDGS) that are naturally contaminated with deoxynivalenol (DON).

Methods

One hundred and sixty 52-week-old Lohmann Brown Lite hens were randomly allotted to five dietary treatments with 8 replicates per treatment. The dietary treatments were formulated to provide a range of corn DDGS contaminated with DON from 0% to 20% (i.e., 5% scale of increment). All laying hens were subjected to the same management practices in a controlled environment. Body weight, feed intake and egg production were measured biweekly for the entire 8-week experiment. The egg quality was measured biweekly for 8 weeks. On weeks 4 and 8, visceral organ weights, blood metabolites, intestinal morphology, and blood cytokine concentrations were measured.

Results

The inclusion of corn DDGS contaminated with DON in the diet did not alter (p> 0.05) the body weight, feed intake, hen-day egg production, egg mass and feed efficiency of the laying hens. No difference was found (p>0.05) in the egg quality of hens that were fed the dietary treatments. Furthermore, hens that were fed a diet containing corn DDGS contaminated with DON showed no change (p>0.05) in the visceral organ weights, the blood metabolites, and the cytokine concentrations. The crypt depth increased (p<0.05) as the amount of corn DDGS contaminated with DON increased. Proportionately, the villus height to crypt depth ratio of the laying hens decreased (p<0.05) with the increasing level of corn DDGS contaminated with DON in the diet.

Conclusion

The inclusion of corn DDGS contaminated with DON up to 20% in layer diets did not cause changes in egg production performance and egg quality, which indicates that DON is less toxic at the concentration of 1.00 mg DON/kg.

Validation of reference genes for quantitative gene expression analysis in Auricularia cornea

Auricularia cornea Ehrenb., previously named A. polytricha (Mont.) Sacc, has become one of the most widely cultivated mushrooms in China. Considerable research has been conducted on its cultivation, pathogen identification, proteomics, and more. However, to the best of our knowledge, no studies have been performed on reference-gene validation in this species. Formerly, reference genes were selected for their expression levels only relied upon from others species, owing to the fact that the gene stability in this species is unknown. In this study, nine candidate genes, including tubulin alpha-1A chain (TUBA1A), β-tubulin (Btu), phosphoglucomutase (Pgm), actin 1 (Act1), protein phosphatase 2A regulatory subunit (PP2A), polyubiquitin (UBQ), glyceraldehyde-3-phosphate dehydrogenase (Gapdh), 18S ribosomal protein (18S) and 28S ribosomal protein (28S), were evaluated among different strains and developmental stages. Four algorithms (i.e., geNorm, NormFinder, BestKeeper and RefFinder) were used to analyze candidate genes. The results revealed that UBQ was the most stable reference gene, while 18S was the least stable. Despite these results, the candidate genes were largely inadequate and only two were considered suitable. Based on candidate gene stability, PP2A and UBQ were identified as a set of usable interior control genes for future analyses in this species. This is the first systematic study conducted for selecting reference genes in A. cornea, and lays the foundation for identifying genes and quantifying gene expression in this species.

Changes in the intestinal mucosal proteome of turkeys (Meleagris gallopavo) infected with haemorrhagic enteritis virus

Haemorrhagic enteritis (HE) is a viral disease affecting intestinal integrity and barrier function in turkey (Meleagris gallopavo) and resulting in a significant economic loss. Sequential Windowed Acquisition of All Theoretical Fragment Ion Mass Spectra (SWATH-MS) was applied to identify crucial proteins involved in HE infection. A total of 938 proteins were identified and used to generate a reference library for SWATH-MS analysis. In total, 523 proteins were reliably quantified, and 64 proteins were found to be differentially expressed, including 49 up-regulated and 15 down-regulated proteins between healthy and HE-affected intestinal mucosa. Functional analysis suggested that these proteins were involved in the following categories of cellular pathways and metabolisms: 1) energy pathways; 2) intestine lipid and amino acid metabolism; 3) oxidative stress; 4) intestinal immune response. Major findings of this study demonstrated that natural HE infection is related to the changes in abundance of several proteins involved in cell-intrinsic immune defense against viral invasion, systemic inflammation, modulation of excessive inflammation, B and T cell development and function and antigen presentation. mRNA quantitative expression demonstrated that most of the proteins involved in innate immunity that were found to be differentially abundant were produced by intestinal mucosa, suggesting its direct involvement in immune defences against HE infection.

Effects of ammonia on intestinal microflora and productive performance of laying ducks

Atmospheric ammonia is harmful to poultry and human health. The effect of ammonia on the intestinal microflora of laying ducks is still unknown. In this study, the effects of atmospheric ammonia and exposure time on the intestinal microflora of laying ducks were investigated using 16S rDNA sequencing technology. The body weight, ovary weight, spleen weight, liver weight, and productive performance of laying ducks were also recorded, and the relationship between intestinal microflora diversity and productive performance was analyzed. The results showed that Bacteroidetes, Firmicutes, and Proteobacteria were the dominant bacterial phyla. At the phylum and genus levels, with the exception of the phylum Firmicutes and the genus Sutterella, the top 10 most abundant phyla and genera differed significantly when the ammonia concentration was increased from 10 to 75 ppm and/or the exposure time was extended from 10 to 30 D. Laying rate was highly significantly lower in ducks exposed to 75 ppm ammonia for 10 D compared with those exposed to 10 ppm ammonia for 10 D. Body, ovary, and spleen weights also decreased when the ammonia concentration was increased. At the genus level, Flavonifractor was highly significantly positively correlated with ovary weight. Methanocorpusculum and Anaerotruncus were significantly positively correlated with ovary weight. Lactobacillus was significantly positively correlated with spleen weight. Phascolarctobacterium, Sphaerochaeta, Erysipelotrichaceae_UCG.004, and Lactococcus were significantly positively correlated with spleen weight. These results indicated that ammonia affected the diversity of the intestinal microbiota and the productive performance of laying ducks. Several intestinal microbiota genera were also correlated with organ weights.

Ammonia exposure induced abnormal expression of cytokines and heat shock proteins via glucose metabolism disorders in chicken neutrophils

Ammonia (NH₃) is a highly irritant, alkaline gas. Atmospheric emission of NH₃ was recognized as an environmental challenge. As a global issue, the NH₃ emission survey with spatially detailed information demonstrated that the sources of atmospheric NH₃ include agriculture (livestock wastes, fertilizers) and some industrial activities. As an environmental pollution, excessive NH₃ exposure can induce many bird dysfunction. Neutrophils respond to multiple invading pathogens through different mechanisms. In order to investigate the effect of NH₃ exposure on broilers' neutrophil, 1-day-old broilers were treated with/without NH₃ for 28 days. We extracted neutrophils from peripheral blood of chicken with/without NH₃ exposure and subsequently stimulated with PMA. Changes of cytokines and inflammatory bodies, heat shock proteins (HSPs), and glucose metabolism of neutrophil were examined in both cases. We not only explored that the index associated with inflammation changed due to NH₃ exposure but also observed the status of neutrophils which was treated with PMA stimulation. After NH₃ exposure, IL-1β and IL-6 were significantly increased on broilers neutrophil. Inflammatory-related factors (NLRP3, ASC, and caspase-1) were significantly elevated. The mRNA expression of HSP70 and HSP90 was increased significantly. All glucose metabolism indicators were reduced. In summary, we concluded that NH₃ enhanced inflammation and disrupted glucose metabolism, and increased the expression of HSPs and inflammatory factors. In addition, the sensitivity of neutrophils to exogenous stimuli was diminished. This information can not only be used to evaluate the damage of NH₃-spiked neutrophils to chickens, but also provide clues for human health pathophysiology caused by excess NH₃, providing valuable information for NH₃ risk management.

Proteomics alterations in chicken jejunum caused by 24 h fasting

The small intestine is the longest part of the chicken (Gallus gallus) gastrointestinal system that is specialized for nutrient absorption. It is known that decrease in intestinal villi area or height in early age can cause a reduction in essential nutrient intake, which may lead to delayed growth and consequently poorer performance of broiler chickens. The small intestinal absorptive surface is known to be affected by various factors, among others things the nutritional state. In our experiment, we aimed to investigate the possible protein expression alterations that lie behind the villus area and height decrease caused by feed deprivation. A total of 24 chickens were divided into three groups, namely ad libitum fed, fasted for 24 h, fasted for 24 h then refed for 2 h. The morphometric parameters were also measured in the duodenum, jejunum and ileum tissue sections using image analysis. Differential proteome analyses from jejunum samples were performed using two-dimensional difference gel electrophoresis followed by tryptic digestion and protein identification by matrix-assisted laser desorption/ionization mass spectrometry. Overall 541 protein spots were detected after 2D. Among them, eleven showed 1.5-fold or higher significant difference in expression and were successfully identified. In response to 24 h fasting, the expression of nine proteins was higher and that of two proteins was lower compared to the ad libitum fed group. The functions of the differentially expressed proteins indicate that the 24 h fasting mainly affects the expression of structural proteins, and proteins involved in lipid transport, general stress response, and intestinal defense.

Oxidative Stress in the Poultry Gut: Potential Challenges and Interventions

The gastrointestinal tract (GIT) provides the biological environment for nutrient digestion and absorption, and protection from pathogens and toxins. Broilers are fast growing because of the great potential of intestinal epithelia for nutrient absorption, and efficient conversion of nutrient to muscle. Physiologically, reactive oxygen species (ROS) and reactive nitrogen species (RNS) are generated by GIT epithelial cells either from oxygen metabolism or by enteric commensal bacteria and regulate gut health. However, increased production of ROS elevates free radical production and antioxidant insults resulting in oxidative stress. Oxidative stress in poultry GIT is derived from nutritional, environmental heat stress, and pathological factors, which alters overall performance as well as meat and egg quality. Supplementation of exogenous vitamins, antioxidants, and plant extract having antioxidant properties scavenge ROS and are beneficial in mitigating oxidative stress in the GIT. This review highlights the involvement of oxidative stress in the gastrointestinal functionality of poultry and potential intervention strategies to maintain redox balance in the GIT.

A method to culture chicken enterocytes and their characterization

Enterocytes function as both absorptive and protective components of intestine that come in close contact with a variety of enteric factors, such as dietary, microbial, and parasites, that have potential to affect the organismal health. Understanding how enterocytes interact with this complex array of factors may help improve gut health particularly in the context of poultry production where it is also linked to food safety issues. The enterocyte in vitro culture can help screen different factors and their interactions with microbiome, and potentially be utilized in the development of interventions strategies for pathogens such as antibiotic alternatives. We developed a method to culture primary chicken enterocytes and conducted their characterization using cytochemical and proteomic methods, and investigated their potential to respond to different chemical stimuli. Using selected micronutrients, microbial toxins, and metabolic modulators, we assessed their effects on the viability and morphological changes in enterocytes. We found that whereas some nutritional factors (calcitriol, retinoic acid) produced different morphological changes, toxins such as aflatoxin B1 and deoxynivalenol produced enterocyte degeneration and death, and the bacterial lipopolysaccharide had very little effect compared on the basis of their mass. Both cyclic AMP and phorbol myristate acetate exhibited some cachectic effects on enterocytes with the later showing more severe changes. Thyroxin induced distinct morphological changes making the cells more cuboidal and Na-butyrate produced no significant change in morphology. The cytochemical and proteomic characterization suggest that these enterocytes largely belong to epithelial cell categories which may be amenable to analysis of biochemical paths and mechanisms of action of different factors that affect these cells. Based on these results we conclude that chicken enterocyte culture can be a useful in vitro model to study intestinal physiology.

The effect of microbial challenge on the intestinal proteome of broiler chickens

Background

In poultry production intestinal health and function is paramount to achieving efficient feed utilisation and growth. Uncovering the localised molecular mechanisms that occur during the early and important periods of growth that allow birds to grow optimally is important for this species. The exposure of young chicks to used litter from older flocks, containing mixed microbial populations, is a widely utilised model in poultry research. It rarely causes mortality but effects an immunogenic stimulation sufficient enough to cause reduced and uneven growth that is reflective of a challenging growing environment.

Methods

A mixed microbial challenge was delivered as used litter containing Campylobacter jejuni and coccidial oocysts to 120 male Ross 308 broiler chicks, randomly divided into two groups: control and challenged. On day 12, 15, 18 and 22 (pre- and 3, 6 and 10 days post-addition of the used litter) the proximal jejunum was recovered from 6 replicates per group and differentially abundant proteins identified between groups and over time using 2D DiGE.

Results

The abundance of cytoskeletal proteins of the chicken small intestinal proteome, particularly actin and actin associated proteins, increased over time in both challenged and control birds. Villin-1, an actin associated anti-apoptotic protein, was reduced in abundance in the challenged birds indicating that many of the changes in cytoskeletal protein abundance in the challenged birds were as a result of an increased rate of apoptosis. A number of heat shock proteins decreased in abundance over time in the intestine and this was more pronounced in the challenged birds.

Conclusions

The small intestinal proteome sampled from 12 to 22 days of age showed considerable developmental change, comparable to other species indicating that many of the changes in protein abundance in the small intestine are conserved among vertebrates. Identifying and distinguishing the changes in proteins abundance and molecular pathways that occur as a result of normal growth from those that occur as a result of a challenging microbial environment is important in this major food producing animal.

Proteomic Analysis of Chicken Skeletal Muscle during Embryonic Development

Embryonic growth and development of skeletal muscle is a major determinant of muscle mass, and has a significant effect on meat production in chicken. To assess the protein expression profiles during embryonic skeletal muscle development, we performed a proteomics analysis using isobaric tags for relative and absolute quantification (iTRAQ) in leg muscle tissues of female Xinghua chicken at embryonic age (E) 11, E16, and 1-day post hatch (D1). We identified 3,240 proteins in chicken embryonic muscle and 491 of them were differentially expressed (fold change ≥ 1.5 or ≤ 0.666 and p < 0.05). There were 19 up- and 32 down-regulated proteins in E11 vs. E16 group, 238 up- and 227 down-regulated proteins in E11 vs. D1 group, and 13 up- and 5 down-regulated proteins in E16 vs. D1 group. Protein interaction network analyses indicated that these differentially expressed proteins were mainly involved in the pathway of protein synthesis, muscle contraction, and oxidative phosphorylation. Integrative analysis of proteome and our previous transcriptome data found 189 differentially expressed proteins that correlated with their mRNA level. The interactions between these proteins were also involved in muscle contraction and oxidative phosphorylation pathways. The lncRNA-protein interaction network found four proteins DMD, MYL3, TNNI2, and TNNT3 that are all involved in muscle contraction and may be lncRNA regulated. These results provide several candidate genes for further investigation into the molecular mechanisms of chicken embryonic muscle development, and enable us to better understanding their regulation networks and biochemical pathways.

Maternal nutrition modulates fetal development by inducing placental efficiency changes in gilts

BACKGROUND

Intra-uterine growth restriction (IUGR) and fetal overgrowth increase risks to postnatal health. Maternal nutrition is the major intrauterine environmental factor that alters fetal weight. However, the mechanisms underlying the effects of maternal nutrition on fetal development are not entirely clear. We developed a pig model, and using isobaric tags for relative and absolute quantification (iTRAQ), we investigated alterations in the placental proteome of gilts on a normal-energy-intake (Con) and high-energy-intake (HE) diet.

RESULTS

In the Con group, heavy and light fetuses were found at the tubal and cervical ends of the uterus respectively at 90 d of gestation. Moreover, the heavy fetuses had a higher glucose concentration than the light fetuses. However, a higher uniformity was noted in the HE group. Placental promoters between these two positions indicated that 78 and 50 differentially expressed proteins were detected in the Con and HE groups respectively. In the Con group, these proteins were involved in lipid metabolism (HADHA, AACS, CAD), nutrient transport (GLUT, SLC27A1), and energy metabolism (NDUFV1, NDUFV2, ATP5C1). However, in the HE group they mainly participated in transcriptional and translational regulation, and intracellular vesicular transport.

CONCLUSIONS

Our findings revealed that maternal nutrition may alter birth weight mainly through the modulation of placental lipid and energy metabolism, which also provides a possible mechanism to explain the higher uniformity of fetal weight in gilts fed a HE diet.

Differential expression analysis of the broiler tracheal proteins responsible for the immune response and muscle contraction induced by high concentration of ammonia using iTRAQ-coupled 2D LC-MS/MS

Ammonia has been considered the contaminant primarily responsible for respiratory disease in poultry. Even though it can cause tracheal lesions, its adverse effects on the trachea have not been sufficiently studied. The present study investigated tracheal changes in Arbor Acres broilers (Gallus gallus) induced by high concentration of ammonia using isobaric tag for relative and absolute quantification (iTRAQ)-based proteome analysis. In total, 3,706 proteins within false discovery rate of 1% were identified, including 119 significantly differentially expressed proteins. Functional analysis revealed that proteins related to immune response and muscle contraction were significantly enriched. With respect to the immune response, up-regulated proteins (like FGA) were pro-inflammatory, while down-regulated proteins participated in antigen processing and antigen presenting (like MYO1G), immunoglobulin and cathelicidin production (like fowlicidin-2), and immunodeficiency (like PTPRC). Regarding muscle contraction, all differentially expressed proteins (like TPM1) were up-regulated. An over-expression of mucin, which is a common feature of airway disease, was also observed. Additionally, the transcriptional alterations of 6 selected proteins were analyzed by quantitative RT-PCR. Overall, proteomic changes suggested the onset of airway obstruction and diminished host defense in trachea after ammonia exposure. These results may serve as a valuable reference for future interventions against ammonia toxicity.

Protein Profiles for Muscle Development and Intramuscular Fat Accumulation at Different Post-Hatching Ages in Chickens

Muscle development and growth influences the efficiency of poultry meat production, and is closely related to deposition of intramuscular fat (IMF), which is crucial in meat quality. To clarify the molecular mechanisms underlying muscle development and IMF deposition in chickens, protein expression profiles were examined in the breast muscle of Beijing-You chickens at ages 1, 56, 98 and 140 days, using isobaric tags for relative and absolute quantification (iTRAQ). Two hundred and four of 494 proteins were expressed differentially. The expression profile at day 1 differed greatly from those at day 56, 98 and 140. KEGG pathway analysis of differential protein expression from pair-wise comparisons (day 1 vs. 56; 56 vs. 98; 98 vs. 140), showed that the fatty acid degradation pathway was more active during the stage from day 1 to 56 than at other periods. This was consistent with the change in IMF content, which was highest at day 1 and declined dramatically thereafter. When muscle growth was most rapid (days 56-98), pathways involved in muscle development were dominant, including hypertrophic cardiomyopathy, dilated cardiomyopathy, cardiac muscle contraction, tight junctions and focal adhesion. In contrast with hatchlings, the fatty acid degradation pathway was downregulated from day 98 to 140, which was consistent with the period for IMF deposition following rapid muscle growth. Changes in some key specific proteins, including fast skeletal muscle troponin T isoform, aldehyde dehydrogenase 1A1 and apolipoprotein A1, were verified by Western blotting, and could be potential biomarkers for IMF deposition in chickens. Protein-protein interaction networks showed that ribosome-related functional modules were clustered in all three stages. However, the functional module involved in the metabolic pathway was only clustered in the first stage (day 1 vs. 56). This study improves our understanding of the molecular mechanisms underlying muscle development and IMF deposition in chickens.