Ammonia concentration and relative humidity in poultry houses affect the immune response of broilers

The influence of relative humidity during the first 21 days post-hatch on the production performance, biochemical indices, and meat quality of Pekin ducks

This study aims to investigate the effects of different relative humidity (RH) during 4-21d of Beijing ducks on their condition at 42 d. A total of 48 Pekin duck were randomly allotted into 4 treatments (A:RH60 %, B:RH67 %,C:RH74 %,D:RH81 %), each having 3 replicates of 4 ducks. Different humidity treatments were applied from 4 to 21 days. At 42 d, there were no significant differences (P > 0.05) in body weight (BW), average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) among the 4 groups. Oblique body length in D was significantly higher than that in A (P < 0.05). Compared with A, the chest depth of the other groups was significantly increased, and the abdominal fat weight of B and C was significantly increased (p < 0.05). Liver weight and liver index in C and D significantly higher than that in B (p < 0.05). Abdominal fat ratio in B was significantly higher than that in A (P < 0.05). Cholesterol (CHOL) in D was significantly higher than that in A and C (P < 0.05), triglyceride (TG) in C was significantly higher than that in A and B (P < 0.05), and low-density lipoprotein cholesterol (LDL-C) in B was significantly higher than that in A, C, and D (P < 0.05). pH in B was significantly higher than that in A (P < 0.05), brightness (L*) in A was significantly higher than that in B and C (P < 0.05), redness (a*) in B and C was significantly higher than that in A and D (P < 0.05), and yellowness (b*) in C was significantly lower than that in A and D (P < 0.05).The results indicate that the RH of environment during the brooding period has no impact on duck production performance but induces some oxidative stress damage and changes in meat quality. Additionally, ducks subjected to different RH treatments during the brooding period exhibit varying adaptability to the same environment as they mature.

Identification and functional analysis of circular RNA expression profiles associated with ammonia exposure in chicken lungs

Ammonia acts as a detrimental atmospheric pollutant, posing a sever threat to respiratory tract health and causing lung injury in humans and animals. Circular RNAs (circRNAs) are a distinctive class of non-coding RNA generated by back-splicing of linear RNA, implicated in various biological processes. However, their role in the immune response of chicken lungs to ammonia exposure remains unclear. In this study, we examined the expression profiles of circRNAs in chicken lungs under ammonia stimulation. In total, 61 differentially expressed (DE) circRNAs were identified between the ammonia exposure and control groups, including 17 up-regulated and 44 down-regulated circRNAs. The source genes of these DE circRNAs were predominantly enriched in Influenza A, SNARE interactions in vesicular transport, and Notch signaling pathway. Notably, nine DE circRNAs (circNBAS, circMTIF2, circXPO1, circSNX24, circRAB11A, circARID3B, circUSP54, circPPARA, and circERG) were selected for validation the reliability and authenticity of RNA-seq data. Results showed the back-splicing circular structure, as well as the reliability and accuracy of RNA-seq data in quantifying circRNA expression, as the RT-qPCR results were in agreement with the RNA-seq data. Moreover, we constructed the circRNA-miRNA-mRNA regulatory networks and identified several regulatory networks in chicken lungs under ammonia stimulation, including circRAB11A-gga-miR-191b-3p-BRD2 and circARID3B-gga-miR-1696-CKS2. Taken together, our study delineates the circRNA expression profile and their potential roles in the immune response of chicken lungs to ammonia exposure. These findings offer insights into molecular mechanisms that may mitigate diseases associated with ammonia induced respiratory tract pollution in humans and animals.

Postbiotic, anti-inflammatory, and immunomodulatory effects of aqueous microbial lysozyme in broiler chickens

Lysozymes, efficient alternative supplements to antibiotics, have several benefits in poultry production. In the present study, 120, one-day-old, Ross 308 broiler chickens of mixed sex, were allocated into 2 equal groups, lysozyme treated group (LTG) and lysozyme free group (LFG), to evaluate the efficacy of lysozyme (Lysonir®) usage via both drinking water (thrice) and spray (once). LTG had better (p = 0.042) FCR, and higher European production efficiency factor compared to LFG (p = 0.042). The intestinal integrity score of LTG was decreased (p = 0.242) compared to that of LFG; 0.2 vs. 0.7. Higher (p ≤ 0.001) intestinal Lactobacillus counts were detected in chickens of LTG. Decreased (p ≤ 0.001) IL-1β and CXCL8 values were reported in LTG. The cellular immune modulation showed higher (p ≤ 0.001) opsonic activity (MΦ and phagocytic index) in LTG vs. LFG at 25 and 35 days. Also, higher (p ≤ 0.001) local, IgA, and humoral, HI titers, for both Newcastle, and avian influenza H5 viruses were found in LTG compared to LFG. In conclusion, microbial lysozyme could improve feed efficiency, intestinal integrity, Lactobacillus counts, anti-inflammatory, and immune responses in broiler chickens.

In-house ammonia induced lung impairment and oxidative stress of ducks

Ammonia (NH3) is a toxic gas that in intensive poultry houses, damages the poultry health and induces various diseases. This study investigated the effects of NH3 exposure (0, 15, 30, and 45 ppm) on growth performance, serum biochemical indexes, antioxidative indicators, tracheal and lung impairments in Pekin ducks. A total of 288 one-day-old Pekin male ducks were randomly allocated to 4 groups with 6 replicates and slaughtered after the 21-d test period. Our results showed that 45 ppm NH3 significantly reduced the average daily feed intake (ADFI) of Pekin ducks. Ammonia exposure significantly reduced liver, lung, kidney, and heart indexes, and lowered the relative weight of the ileum. With the increasing of in-house NH3, serum NH3 and uric acid (UA) concentrations of ducks were significantly increased, as well as liver malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPX-Px) contents. High NH3 also induced trachea and lung injury, thereby increasing levels of tumor necrosis factor-α (TNF-α) and interleukin-4 (IL-4) in the lung, and decreasing the mRNA expressions of zonula occludens 1 (ZO-1) and claudin 3 (CLDN3) in the lung. In conclusion, in-house NH3 decrease the growth performance in ducks, induce trachea and lung injuries and meanwhile increase the compensatory antioxidant activity for host protection.

Impacts of longitudinal water curtain cooling system on transcriptome-related immunity in ducks

BACKGROUND

The closed poultry houses integrated with a longitudinal water curtain cooling system (LWCCS) are widely used in modern poultry production. This study showed the variations in environmental conditions in closed houses integrated with a longitudinal water curtain cooling system. We evaluated the influence of different environmental conditions on duck growth performance and the transcriptome changes of immune organs, including the bursa of Fabricius and the spleen.

RESULT

This study investigated the slaughter indicators and immune organ transcriptomes of 52-day-old Cherry Valley ducks by analyzing the LWCC at different locations (water curtain end, middle position, and fan cooling end). The results showed that the cooling effect of the LWCCS was more evident from 10:00 a.m. -14:00. And from the water curtain end to the fan cooling end, the hourly average temperature differently decreased by 0.310℃, 0.450℃, 0.480℃, 0.520℃, and 0.410℃, respectively (P < 0.05). The daily and hourly average relative humidity decreased from the water curtain end to the fan cooling end, dropping by 7.500% and 8.200%, respectively (P < 0.01). We also observed differences in production performance, such as dressing weight, half-eviscerated weight, skin fat rate, and percentage of abdominal fat (P < 0.01), which may have been caused by environmental conditions. RNA-sequencing (RNA-seq) revealed 211 and 279 differentially expressed genes (DEGs) in the ducks' bursa of Fabricius and spleen compared between the water curtain end and fan cooling end, respectively. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of the two organs showed the DEGs were mainly enriched in cytokine-cytokine receptor interaction, integral component of membrane, Retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) signaling pathway, etc. Our results implied that full-closed poultry houses integrated with LWCCS could potentially alter micro-environments (water curtain vs. fan cooling), resulting in ducks experiencing various stressful situations that eventually affect their immunity and production performance.

CONCLUSION

In this study, our results indicated that uneven distributions of longitudinal environmental factors caused by LWCCS would affect the dressed weight, breast muscle weight, skin fat rate, and other product performance. Moreover, the expression of immune-related genes in the spleen and bursa of ducks could be affected by the LWCCS. This provides a new reference to optimize the use of LWCCS in conjunction with close duck houses in practical production.

Effect of Hardwood Dust and Ammonia Gas on the Respiratory Integrity of Broiler Chickens

Dust and ammonia gas (NH3) are two of the most abundant pollutants suspended in the air of poultry houses. Chronic inhalation of poultry dust and NH3 causes damage to the airways and reduces performance in broilers. Poultry dust is a mixture of organic and inorganic matter from feed, bedding material, manure, feathers, skin debris, and microorganisms. Thus, the composition and concentration of poultry dust vary among farms. This study proposes a model to assess the individual effect of a defined fraction of poultry dust derived from bedding material (wood dust) and its effects, alone or combined with NH3, on the performance and respiratory integrity of broilers. Ninety-six, 1-day-old broilers were randomly divided into groups of 24 and placed into four controlled environment chambers to continuously receive one of four treatments: 1) negative control; 2) exposure to airborne red oak wood dust at a concentration of 7.5 × 106 particles/m3 (particulate matter5.0); 3) exposure to 50 parts per million (ppm) of NH3; and 4) exposure to airborne red oak wood dust and 50 ppm of NH3. On day 43, all birds were weighed and euthanized. Performance data were recorded. Tissue samples were collected from six birds per treatment. Histologic evaluations of the nasal turbinates, trachea, and lungs were conducted. Histologic lesion scores (0 to 3) were assigned, and tracheal mucosal thickness was measured. No significant differences among treatments were found in body weight (P = 0.066), tracheal mucosal thickness (P = 0.593), or tracheal lesion score (P = 0.07). The average nasal turbinate lesion scores were higher in the wood and wood + ammonia treatments compared with the control (P = 0.015). The lung lesion scores were higher (P = 0.004) in all treatment groups compared with the control. In conclusion, chronic exposure to red oak wood dust, alone or in combination with NH3, induced important inflammatory damage to portions of the respiratory system of broilers; however, no significant effects on performance were observed.

Modulation of the immune system of chickens a key factor in maintaining poultry production-a review

The awareness of poultry production safety is constantly increasing. The safety of poultry production is defined as biosecurity and the health status of birds. Hence the constant pursuit of developing new strategies in this area is necessary. Biosecurity is an element of good production practices that ensures adequate hygiene and maintaining the health status of poultry production. Poultry production is the world leader among all livestock species. Producers face many challenges during rearing, which depend on the utility type, the direction of use, and consumer requirements. For many years, the aim was to increase production results. Increasing attention is paid to the quality of the raw material and its safety. Therefore, it is crucial to ensure hygiene status during production. It can affect the immune system's functioning and birds' health status. Feed, water, and environmental conditions, including light, gases, dust, and temperature, play an essential role in poultry production. This review aims to look for stimulators and modulators of the poultry immune system while affecting the biosecurity of poultry production. Such challenges in current research by scientists aim to respond to the challenges posed as part of the One Health concept. The reviewed issues are a massive potential for an innovative approach to poultry production and related risks as part of the interaction of the animal-human ecosystem.

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.

Influence of Improved Microclimate Conditions on Growth and Physiological Performance of Two Japanese Quail Lines

Microclimate parameters (ammonia, ambient temperature, heat index, and relative humidity) surrounding birds affect the production and health status of poultry. Therefore, this study aimed to evaluate the impact of adding natural zeolite to the litter of Japanese quail on improving microclimate parameters and its reflection in growth performance, blood gases, and blood biochemical parameters. A total of 1152 chicks were obtained from the same hatch at the 20th selection generation. Chicks were allocated into two groups based on the litter composition: Group 1: wheat straw as litter (untreated group); Group 2: 80% wheat straw + 20% zeolite (treated group). Each group consisted of 576 chicks: 410 selected line chicks and 166 control line chicks. Significant and favorable effects of the treatment on microclimate parameters during tested periods were found to favor the treated group. Either the treated group or the selected line had significantly better growth performance than the untreated group and control line. Zeolite-treated quails had significantly desirable blood gases and lower blood acidity and serum total iron binding capacity compared to the untreated group. Thus, adding natural zeolite to the litter enhanced the microclimate parameters that improved growth performance, blood gases, and blood biochemical parameters and reduced ammonia emission.

Temporal dynamics of the cecal and litter microbiome of chickens raised in two separate broiler houses

In this study, we investigated the dynamics of the ceca and litter microbiome of chickens from post-hatch through pre-harvest. To achieve this, six hundred one-day old Cobb 500 broiler chicks were raised on floor pens for 49 days in two separate houses. We performed short-read and full-length sequencing of the bacterial 16S rRNA gene present in the meconium and in cecal and litter samples collected over the duration of the study. In addition, we determined the antimicrobial resistance (AMR) phenotype of Escherichia coli and Enterococcus spp. isolated from the meconium and the ceca of 49-day old chickens. We monitored the relative humidity, temperature, and ammonia in each house daily and the pH and moisture of litter samples weekly. The overall microbial community structure of the ceca and litter consistently changed throughout the course of the grow-out and correlated with some of the environmental parameters measured (p < 0.05). We found that the ceca and litter microbiome were similar in the two houses at the beginning of the experiment, but over time, the microbial community separated and differed between the houses. When we compared the environmental parameters in the two houses, we found no significant differences in the first half of the growth cycle (day 0-21), but morning temperature, morning humidity, and ammonia significantly differed (p < 0.05) between the two houses from day 22-49. Lastly, the prevalence of AMR in cecal E. coli isolates differed from meconium isolates (p < 0.001), while the AMR phenotype of cecal Enterococcus isolates differed between houses (p < 0.05).

Oxidative stress mediated immunosuppression caused by ammonia gas via antioxidant/oxidant imbalance in broilers

1. Ammonia is one of major air pollutants in intensive poultry houses, where it causes immunosuppression in broilers. Although previous studies have focused on a particular organ, data on multiple organs have not been reported.2. In the following work, broilers were exposed to environmental ammonia (0, 10, 20, and 40 mg/m³ from 1-21 d old; and 0, 15, 30, and 60 mg/m³ from 22-42 d old).3. Ammonia exposure reduced bird spleen index at 42 d and thymus index at 14, 28, 35 and 42 d, meaning that ammonia caused immunosuppression in birds. Moreover, high ammonia exposure down-regulated the expression of toll-like receptor 4 (TLR4) in lung tissue at 21 d, as well as TLR4 in lung and tracheal mucosa at 42 d when analysed using qRT-PCR. It increased SIgA in saliva at 42 d when analysed by ELISA. Ammonia increased interleukin-6 (IL-6), IL-1β, interferon-α (IFN-α), and IFN-γ in serum at 28 d from the ELISA assay, which indicated that all of these factors took part in ammonia-immunosuppression in birds.4. Three antioxidants (CAT, SOD, T-AOC) decreased, and one oxidant MDA increased after ammonia exposure in the liver and blood, which indicated that ammonia caused oxidative stress via the imbalance of antioxidants/oxidants in birds.5. Correlation analysis showed that TLR4 and TLR15 in the tracheal mucosa were significantly positively related to IFN-γ and negatively related to IL-6. TLR2 in the lung was significantly positively related to IL-1β, and TLR2 in bird tracheal mucosa was negatively related to IL-6 in serum.6. The results suggested that oxidative stress mediated immunosuppression caused by ammonia gas via antioxidant/oxidant imbalance in broilers.

Effects of the In Ovo Administration of L-ascorbic Acid on the Performance and Incidence of Corneal Erosion in Ross 708 Broilers Subjected to Elevated Levels of Atmospheric Ammonia

Effects of the in ovo injection of various levels of L-ascorbic acid (L-AA) on the performance and corneal erosion incidence in Ross 708 broilers exposed to 50 parts per million (ppm) of atmospheric ammonia (NH3) after hatch were determined. A total of 1440 Ross 708 broiler embryos were randomly assigned to 4 treatments: non-injected (control), 0.85% sterile saline-injected (control), or saline containing 12 or 25 mg of L-AA. At hatch, 12 male chicks were randomly assigned to each of 48 battery cages with 12 replicate cages randomly assigned to each treatment group. All birds were exposed to 50 ppm of NH3 for 35 d and the concentration of NH3 in the battery cage house was recorded every 20 s. Mortality was determined daily, and mean body weight (BW), BW gain (BWG), average daily BW gain (ADG), and feed intake, as well as feed conversion ratio (FCR), were determined weekly. From 0 to 35 d of post-hatch age (doa), six birds from each cage were selected and sampled for eye erosion scoring. Incidences of corneal erosion were significantly higher at 21 and 28 doa in comparison to those at 14 and 35 doa, and at 21 doa, birds in the saline-injected group exhibited a higher incidence of corneal erosion compared to all other treatment groups. The in ovo injection of 12 mg of L-AA increased BWG (p = 0.043) and ADG (p = 0.041), and decreased FCR (p = 0.043) from 0 to 28 doa in comparison to saline-injected controls. In conclusion the in ovo administration of 12 mg of L-AA may have the potential to improve the live performance of broilers chronically exposed to high aerial NH3 concentrations, but further study is needed to determine the physiological and immunological factors that may contribute to this improvement.

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.

Comparison and Correlation Analysis of Immune Function and Gut Microbiota of Broiler Chickens Raised in Double-Layer Cages and Litter Floor Pens

This study aimed to compare the immune function and gut microbiota between double-layer caged and litter floor pen-raised broiler chickens. Eighty meaty male chicks were selected and divided into cage group and litter floor group, with 20 replicates in each group. The broilers were raised in the same chicken house. The rearing density of the two rearing systems was same. The broilers were sampled on days 13 and 34. The results showed that compared with the cage group, the litter floor broilers had worse growth performance (23.24% increase in feed conversion ratio) in the early stage; better slaughter performance at day 42; stronger peripheral immune function (including higher lysozyme activity, T-cell ratio, Th-cell ratio, Tc-cell ratio, CD4/CD8, IL-10, B-cell ratio, IgG and IgA levels; and spleen immune-related gene expression); and stronger intestinal immune function (including higher ileum CD80, AvBD2, Mucin2, NF-κB, IL-8, IFN-γ/IL-4, and IgA mRNA expression levels and ileal mucosa sIgA levels). Compared with the cage group, the alpha diversity of ileum microbiota of the litter floor broilers was higher, and the relative abundance levels of litter breeding bacteria (Facklamia, Globicatella, and Jeotgalicoccus) and potential pathogenic bacteria (Streptococcus and Staphylococcus) were higher (P < 0.05). Through Spearman correlation analysis, it was found that enriched microbes in the ileum of litter floor broilers were positively correlated with immune function. In summary, compared with cage broilers, litter floor broilers had more potential pathogenic bacteria and litter breeding bacteria in the ileum, which may be one of the important reasons for the stronger immune function status. IMPORTANCE In China, the three-dimensional rearing system (cage) for broilers has gradually become a trend. In production, it was found that the incidence of disease in broiler chickens raised in cage systems was significantly higher than that of ground litter. Given that broilers raised on ground litter systems may be exposed to more environmental microbes, it is important to understand whether the rearing environment affects the function and status of the host immune system by altering the gut microbiota. In this study, rearing environment-derived gut microbes associated with stronger immune function in ground litter broilers were provided, which will provide new insights into strategies to target gut microbes to promote immune function and status in broilers raised in cages.

Complex molecular mechanism of ammonia-induced apoptosis in chicken peripheral blood lymphocytes: miR-27b-3p, heat shock proteins, immunosuppression, death receptor pathway, and mitochondrial pathway

Ammonia gas, a toxic environmental pollutant, is a vital component of PM2.5 aerosols, and can decrease human and animal immunity. Peripheral blood lymphocytes (PBLs) are main immune cells. Nevertheless, poisoning mechanism of PBLs under ammonia exposure remains unclear. Here, we established an ammonia poisoning model of chicken PBLs to explore poisoning mechanism of ammonia-caused apoptosis in chicken PBLs. Cell viability and apoptosis rate were detected using CCK8 assay and flow cytometry, respectively. Mitochondrial membrane potential (MMP) was observed using fluorescent staining. In addition, qRT-PCR was performed to measure mRNA levels of apoptosis-related genes (tumor necrosis factor-α (TNF-α), tumor necrosis factor receptor 1 (TNFR1), TNF receptor-associated death domain (TRADD), Fas-associated death domain (FADD), Caspase-8, BH3-interacting domain death agonist (Bid), Bcl-2-associated X protein (Bax), Bcl-2 homologous antagonist/killer (Bak), B-cell lymphoma-2 (Bcl-2), Cytochrome-c (Cytc), apoptotic protease activating factor-1 (APAF1), Caspase-9, and Caspase-3), immune-related genes (interferon-γ (IFN-γ), interleukin-2 (IL-2), IL-4, IL-6, IL-1β, IL-10, transforming growth factor-β1 (TGF-β1), IL-17, IL-21, and IL-22), heat shock protein (HSP) genes (HSP25, HSP40, HSP60, HSP70, HSP90, and HSP110), as well as miR-27b-3p. Western blot was used to determine protein levels of apoptosis-related factors (TNF-α, Caspase-8, Bcl-2, Caspase-9, and Caspase-3), as well as HSPs (HSP40, HSP60, HSP70, and HSP90). The results indicated that TRADD, FADD, and APAF1 were target genes of miR-27b-3p, as well as miR-27b-3p participated in molecular mechanism of apoptosis through targeting TNF-α/TNFR1/Caspase-8 death receptor pathway-triggered Bid/Cytc/Caspase-9 mitochondrial pathway in ammonia-treated chicken PBLs. In addition, our findings demonstrated that excess ammonia led to immunosuppression via Th1/Th2 imbalance and Treg/Th17 imbalance. Simultaneously, ammonia stress activated HSPs. In summary, for the first time, our data demonstrated that HSPs-triggered immunosuppression led to apoptosis under ammonia exposure. Our findings provided a new insight into molecular mechanism of ammonia poisoning and an important reference for environmental risk assessment related to ammonia.

Assessment of Husbandry Practices That Can Reduce the Negative Effects of Exposure to Low Ammonia Concentrations in Broiler Houses

Simple Summary

We used two commercial breeds, differing in growth rate: Fast-growing breed and slow-growing breed. We stocked these birds in two different densities. The slow-growing birds was stocked at a high density and the fast-growing birds at a high density and low density. These birds were reared under two different environmental conditions: A control room with a low concentration of ammonia and a second room with a higher concentration. We analyzed management practices such as the effect of ventilation, animal density and growth rate as management possibilities to reduce the negative effect of ammonia on production parameters.

Abstract

Ammonia is an important pollutant emitted by broiler litter that can accumulate inside farms, impairing animal health and welfare productivity. An experiment was designed to evaluate of precision husbandry practices such as the effect of ventilation, animal density and growth rate as management options to reduce the adverse effects of ammonia exposure on productive parameters in broiler houses. Two identical experimental rooms were used in this study. They were programmed to differ in ammonia concentration from day 32 of the growing period (10 and 20 ppm in Room 1 and Room 2, respectively). Three treatments were tested in each room: slow growth in high stocking density (SHD), fast growth in low density (FLD) and fast growth in high density (FHD). Animal weight, feed intake and feed conversion ratio were determined weekly. In addition, the immune status of animals was assessed by weighing the organs related to immune response as stress indicators. Increasing ventilation was effective to control ammonia concentrations. Exposure to ammonia caused no significant effect on productive parameters. However, lowering stocking density improved response to higher ammonia concentrations by lowering the feed conversion ratio. No other relevant effects of differential exposure to ammonia were found in fast-growing animals, either at high or low stocking density. The use of slow-growing breeds had no effect on production parameters. Despite having a slower growth rate, their feed conversion ratio was not different from that of fast-growing breeds. The productive performance of slow-growing animals was not affected by the differential exposure to ammonia, but the reduced spleen size would suggest an impairment of the immune system.

Atmospheric Ammonia Causes Histopathological Lesions, Cell Cycle Blockage and Apoptosis of Spleen in Chickens

The experiment was conducted to investigate the effect of atmospheric ammonia (NH3) on histological changes, cell cycle distribution, and apoptosis of spleen in chickens. 240 chickens were randomly allocated to control group (without NH3 challenge) and NH3 group (70±5 ppm NH3). The experiment lasted for eight days. The results showed that NH3 exposure caused the decreased relative weight (P<0.05), dysplasia of lymphatic follicle, up-regulation of G0G1 phase cells, excessive apoptosis, and increase of reactive oxygen spcecies (ROS) activated cells (P<0.05) in the spleen. The mechanisms of cell cycle blockage were closely related to the upregulation of p53, p21 gene (P<0.05), the downregulation of cyclinD1, cdk6 gene (P<0.05), and the decrease of Proliferating Cell Nuclear Antigen (PCNA) protein (P<0.05). The activated apoptosis could resulted from the increased gene and protein expressions of bax and caspase-3 (P<0.05), and the decreased gene and protein expressions of bcl-2 (P<0.05). The results suggested that 70±5 ppm NH3 caused the spleen dysplasia, which were closely related to the cell cycle arrest and mitochondria apoptotic pathway activation.

Recovery of E. coli From Liver and Spleen of Broiler Birds and the Effects of Induced High Ammonia Level on Haematobiochemical Parameters and Its Amelioration by Different Modifiers

The poultry sector is one of the most vibrant segments of the agriculture industry of Pakistan. In addition to different infections, ammonia (NH₃) production from litter material of broiler is the most harmful pollutant and causes serious threats for the environment. To overcome this problem, different methods are proposed assuring poultry bird’s health and production. This study was carried out to evaluate the effect of toxic levels of NH₃ on the haematology and serum proteins of broiler birds and its amelioration by using different modifiers. The recovery of Escherichia coli (E. coli) from liver and spleen of broiler birds was also carried out. A total of 100 birds were divided into 5 separate groups (groups A–D). The groups C, D and E were treated with potassium aluminium sulphate, aluminium silicate and Yucca schidigera plant extract, respectively. Blood and tissue samples were collected after slaughtering the birds at 42 days of age. This study revealed increased RBC, total leucocyte count, Hb and heterophils percentage. Serum proteins were decreased in Yucca-treated and potassium aluminium sulphate–treated groups. This study concluded that NH₃ production was reduced by the application of different modifiers, and these modifiers also neutralized the changes in blood parameters induced by NH₃.

Effects of dietary inclusion of Radix Bupleuri extract on the growth performance, and ultrastructural changes and apoptosis of lung epithelial cells in broilers exposed to atmospheric ammonia

To explore whether Radix Bupleuri extract (RBE) could protect lung injury of broilers under ammonia (NH3) exposure, 360 one-d-old male broilers were randomly allocated to four groups of six replicates each in a 2 × 2 factorial design with two diets (the basal diet [control; CON] and the basal diet supplemented with RBE [RB]) and two air conditions (normal condition [<2 ppm of NH3; NOR] and NH3 exposure [70 ppm of NH3; NH70]). The RB diet contained 80 mg saikosaponins/kg diet. On day 7, the lung tissues were collected and the lung epithelial cells (LEC) were isolated. Our experimental results showed that the NH3 exposure decreased body weight gain and feed intake irrespective of dietary treatments during days 1 to 7. However, the RBE addition decreased feed consumption to body weight gain ratio in broilers under NH70 conditions. In the LEC of CON-fed broilers under NH70 conditions, Golgi stacks showed the dilation of cisternaes and reduced secretory vesicles, mitochondria enlarged, the inner membrane of mitochondria became obscure, and the cristae of mitochondria ruptured, whereas only a mild enlargement of Golgi cisternaes and the part rupture of mitochondrial cristaes occurred in the LEC of RB-fed broilers under NH70 conditions. The NH3 exposure increased malondialdehyde (MDA) level, but decreased total antioxidant capacity (T-AOC) in the lungs of CON-fed broilers. However, the RBE addition decreased MDA level and increased T-AOC in the lungs of broilers under NH70 conditions. Simultaneously, the NH3 exposure increased apoptotic rate (AR), mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) level in the isolated LEC of CON-fed broilers. The RBE addition decreased AR, MMP, and ROS in the isolated LEC of broilers under NH70 condition. Besides, the NH3 exposure increased mRNA expression of B-cell lymphoma-2 associated X protein (BAX), caspase-3, and tumor necrosis factor α (TNF-α), but increased interferon γ (IFN-γ) mRNA abundance in the lungs of CON-fed broilers. The RBE supplement decreased mRNA levels of BAX, caspase-3, and TNF-α, but increased IFN-γ, interleukin (IL)-4, and IL-17 mRNA levels in the lungs of broilers under NH70 conditions. These results indicated that dietary RBE addition alleviated NH3 exposure-induced intercellular ultrastructural damage via mitochondrial apoptotic pathway, possibly due to RBE-induced increase of antioxidant capacity and immunomodulatory function in the lungs of broilers under NH3 exposure.

A Heuristic and Data Mining Model for Predicting Broiler House Environment Suitability

The proper combination of environment and flock-based variables plays a critical role in broiler production. However, the housing environment control is mainly focused on temperature monitoring during the broiler growth process. The present study developed a novel predictive model to predict the broiler (Gallus gallus domesticus) rearing conditions' suitability using a data-mining process centered on flock-based and environmental variables. Data were recorded inside four commercial controlled environment broiler houses. The data analysis was conducted in three steps. First, we performed an exploratory and descriptive analysis of the environmental data. In the second step, we labeled the target variable that led to a specific broiler-rearing scenario depending on the age of the birds, the environmental dry-bulb temperature and relative humidity, the ammonia concentration, and the ventilation rate. The output (final rearing condition) was discretized into four categories ('Excellent', 'Good', 'Moderate', and 'Inappropriate'). In the third step, we used the dataset to develop tree models using the data-mining process. The random-tree model only presented accuracy for predicting the 'Excellent' and 'Moderate' rearing conditions. The decision-tree model had high accuracy and indicated that broiler age, relative humidity, and ammonia concentration play a critical role in proper rearing conditions. Using a large amount of data allows the data-mining approach to building up 'if-then' rules that indicate suitable environmental control decision-making by broiler farmers.

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

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

Effects of ammonia on growth performance, lipid metabolism and cecal microbial community of rabbits

This study was designed to investigate the effect of ammonia on growth performance, lipid metabolism and intestinal flora of rabbits. A total of 150 female IRA rabbits (35-days-old) were randomly divided into three groups including 0 ppm (CG), 10 ppm (LAC) and 30 ppm ammonia (HAC) groups for a period of 28 days. The average daily weight gain (ADG) of rabbits was significantly reduced in LAC (-17.11%; p < 0.001) and HAC groups (-17.46%; p < 0.001) as compared with the CG. Serum concentration of high density lipoprotein (HDL) and glucose (Glu) were increased in LAC (+80.95%; +45.99; p < 0.05) and HAC groups (+219.05%; +45.89; p < 0.001), while apolipoprotein A1 (apoA1) was decreased in LAC (-58.49%; p < 0.001) and HAC groups (-36.92%; p < 0.001). The structural integrity of cecum was damaged, and the thickness of mucosa and serosa were significantly decreased in LAC and HAC. The acetate, butyrate and propionate level of cecal chyme were reduced in HAC group (-21.67%; -19.82%; -30.81%; p < 0.05). Microbial diversity and burden of Firmicutes were significantly decreased, while that of pathogenic bacteria, such as Bacteroidetes, Clostridium and Proteobacteria were increased in ammonia treated groups. Spearman's correlation confirmed that burden of Ruminococcaceae_NK4A214_group showed significantly negative correlation with acetic acid (r = -0.67; p < 0.001) while Barnesiellaceae_unclassified showed significantly positive correlation with propionic acid (r = 0.50; p < 0.001). In conclusion, ammonia treatment was responsible for an imbalance of intestinal flora, which affected lipid metabolism and damaged intestinal barrier of rabbits, resulting in low growth performance due to lipid metabolism dysfunction.

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.

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.

Impact of Housing Environment on the Immune System in Chickens: A Review

During their lifespan, chickens are confronted with a wide range of acute and chronic stressors in their housing environment that may threaten their welfare and health by modulating the immune system. Especially chronic stressful conditions can exceed the individual's allostatic load, with negative consequences for immunity. A fully functional immune system is mandatory for health and welfare and, consequently, also for high productivity and safe animal products. This review provides a comprehensive overview of the impact of housing form, light regime as well as aerial ammonia and hydrogen sulfide concentrations on the immune system in chickens. Certain housing conditions are clearly associated with immunological alterations which potentially impair the success of vaccinations or affect disease susceptibility. Such poor conditions counteract sustainable poultry production. This review also outlines current knowledge gaps and provides recommendations for future research.

Effects of atmospheric ammonia on the production performance, serum biochemical indices, and liver RNA-seq data of laying ducks

1. Ammonia is a toxic gas and an air pollutant of great concern. The effects of ammonia-induced damage in ducks are rarely reported. 2. A total of 176 laying ducks were randomly allocated to one of two groups with four replicates and were exposed to ammonia at 5 ± 5 ppm (low ammonia, LA) or 75 ± 5 ppm (high ammonia, HA), respectively, for 30 days. 3. The results showed that atmospheric ammonia exposure significantly decreased body weight and laying performance (P < 0.05). It significantly changed serum biochemical indices by increasing alanine aminotransferase and aspartate aminotransferase (P < 0.05), and decreasing superoxide dismutase activity (P < 0.05). Haematoxylin and eosin staining of hepatocytes revealed severe fatty degeneration. Results of RNA-seq analyses revealed that eight genes were significantly up-regulated in the HA group, which were involved in catalytic activity, single-organism metabolic processes, oxidation-reduction processes, and carbohydrate metabolic processes. 4. These results indicated that atmospheric ammonia exposure reduced production performance, affected serum biochemical indices, and led to severe fatty degeneration in the liver of laying ducks. Differentially expressed genes in liver indicated that there were effects of ammonia exposure on the metabolism and detoxification capabilities in ducks.

Ammonia inhalation-induced inflammation and structural impairment in the bursa of fabricius and thymus of broilers through NF-κB signaling pathway

Ammonia (NH₃) is a toxic, environmental pollutant, and irritant gas. Previous studies reported the toxic effects of NH₃ which led to inflammation in various organs of chicken. However, the exact mechanism of NH₃-induced inflammation in chicken lymphoid organs bursa of fabricius (BF) and thymus is still elusive. Thus, this study was designed to investigate NH₃-induced inflammation in chicken BF and thymus. Experimental chickens were divided into low (5.0 mg/m³), middle (10.0-15.0 mg/m³), and high (20.0-45.0 mg/m³) NH₃-treated groups. To investigate NH₃-induced inflammation in chicken's BF and thymus, histological observation, NO content and iNOS activity, inflammatory cytokine contents, and mRNA levels were performed by light microscopy, microplate spectrophotometer, ELISA assay, and qRT-PCR. The finding of the present study showed that NH₃ exposure reduced BF and thymus index, increased nitric oxide (NO) content and inducible nitric oxide synthase (iNOS) activity, inflammatory cytokine contents and mRNA levels of nuclear factor-kappa B (NF-κB), cyclooxygenase-2 (Cox-2), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), IL-10, IL-1β, IL-18, toll-like receptor 2A (TLR-2A), and iNOS. Histopathological examination revealed signs of inflammation including increased nuclear debris and vacuoles in the cortex and medulla of thymus and bursal follicles. Conclusively, our findings displayed that NH₃ exposure affects the normal function of BF and thymus and led inflammation. The data provided a new ground for NH₃-induced toxicity and risk assessment in chicken production.

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.

The co-expression of circRNA and mRNA in the thymuses of chickens exposed to ammonia

Ammonia (NH₃) is one of major air pollutants in intensive poultry houses, affecting chicken health. Circular RNA (circRNA) is a novel type of RNA that can regulate gene expression and be associated with various biological activities. However, the changes of circRNA caused by excess NH₃ in chickens have not been investigated. We found differentially expressed genes and morphological changes in the thymuses of chickens exposed to NH₃ on day 42. We used a combination of RNA deep sequencing, qRT-PCR, and bioinformatic analysis to explore regulatory mechanism of circRNA and mRNA. Transcriptional profiling results showed that 5 circRNA genes and 100 mRNA genes were significantly dyregulated by high NH₃. The results from GO items showed that immune response and the regulation of cytokine production were involved in the mechanisms of chickens exposed to NH₃. Co-expression analysis found that circRNA-mRNA network was correlated with oxidative stress and inflammation. NH₃ exposure decreased mRNA expression of antioxidant-related genes (GPx and GST4) and increased the mRNA expression of inflammation-related genes (IL-1β, IL-6, IL-8, and iNOS) in chicken thymuses. Histopathologic analysis demonstrated that NH₃ caused inflammatory injury in chicken thymuses. In conclusion, the co-expression of circRNA and mRNA took part in chicken thymus inflammatory injury caused by NH₃. Our study further enriches the mechanism of NH₃ toxicity on chickens, which may be valuable for human and animal health protection.

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.

Whispering gallery mode micro resonators for multi-parameter sensing applications

A novel fiber optic sensing configuration for simultaneously measuring ammonia vapor (NH₃) concentration and relative humidity (RH) in air is proposed and experimentally demonstrated. The system comprised two silica whispering gallery mode (WGM) microsphere resonators coated with different polymer layers. One of the microspheres was dip-coated with sol gel silica polymer and another with a 0.5 % wt./vol. agarose hydrogel. WGMs in both microspheres were excited simultaneously by evanescent coupling using a single adiabatic fiber taper. The optical properties of both coating layers change due to their exposure to ammonia and water molecules in the surrounding atmosphere, resulting in the spectral shifts of the WGM resonances relevant to each of the microspheres. By measuring the relevant WGMs' spectral shifts, the NH₃ concentration in air and the RH can be determined simultaneously. The experimentally demonstrated sensitivity of the proposed sensor array to ammonia was estimated as 19.07 pm/ppm (NH₃ molecules in air) and its sensitivity to relative humidity as 1.07 pm/% RH. Detailed studies of the coatings' cross-sensitivity and temperature dependence are also presented. The proposed sensor array is compact, highly sensitive and potentially low cost.

The effects of atmospheric hydrogen sulfide on peripheral blood lymphocytes of chickens: Perspectives on inflammation, oxidative stress and energy metabolism

Excessive hydrogen sulfide (H₂S) affects poultry health. Exposure to air pollution induces inflammation, oxidative stress, energy metabolism dysfunction and adverse health effects. However, few detailed studies have been conducted on the molecular mechanisms of H₂S-induced injury in poultry. To understand how H₂S drives its adverse effects on chickens, twenty-four 14-day-old chickens were randomly divided into two groups. The chickens in the control group were raised in a separate chamber without H₂S, and the chickens in the treatment group were exposed to 30 ppm H₂S. After 14 days of exposure, peripheral blood samples were taken and the lymphocytes were extracted to detect inflammation, oxidative stress and energy metabolism in broilers. Overall, an increase in the inflammatory response was detected in the peripheral blood lymphocytes following H₂S exposure compared to the control group, and the expression levels of the heat shock proteins (HSPs) and the transcription factors nuclear factor κB (NF-κB), cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) were up-regulated in the H₂S group, which further suggested that H₂S induced an inflammatory response via the NF-κB pathway. Because of the activation of NF-κB, which is a major regulator of oxidative stress, we also observed that reactive oxygen species (ROS) production was elevated under H₂S exposure. In addition, we presumed that energy metabolism might be damaged due to the increased ROS production, and we found that H₂S down-regulated the expression levels of energy metabolism-related genes, which indicated the occurrence of energy metabolism dysfunction. Altogether, this study suggests that exposure to excessive atmospheric H₂S induces an inflammatory response, oxidative stress and energy metabolism dysfunction, providing a reference for comparative medicine.

Ameliorative effect of dietary supplementation of copper oxide nanoparticles on inflammatory and immune reponses in commercial broiler under normal and heat-stress housing conditions

Heat stress (HS) is one of the most serious adverse conditions that affect poultry causing immunosuppression and decreasing production. In a novel approach, we investigated effects of supplementing copper oxide nanoparticles (CuO-NPs) on the immune response in two commercial broiler strains (Ross 308 and Cobb 500). At one day old, birds were divided into 3 groups with 3 replicates for each. The first group received diet supplemented with 100% of their recommended copper requirements as CuO while, in the second and third groups, birds were given diets supplemented with 100% and 50% of the recommended Cu requirements in the form of CuO-NPs, respectively. At age of 21 day, each group was subdivided randomly into normal (24 ± 2 °C) and heat stressed (33 ± 2 °C for 5 h per day for two successive weeks) groups. Under normal housing temperature, CuO-NPs, significantly enhanced the immune response in these birds, compared to CuO shown by the increased levels of phagocytic activity (PA), lysozyme serum activity, and by upregulating immune-modulator genes including NF-κβ, PGES, IL-1β, TGF-1β, IFN-γ, BAX and CASP8. The responses were different between the two studied strains especially at the level of gene expression. In HS birds, supplementation of CuO-NPs reduced HS induced inflammatory conditions, as shown by lower gene expression levels, lower degenerative changes in the spleen, and altered heterophils/lymphocytes (H/L) ratio. We suggest CuO-NPs supplementation, especially in those chickens that received diet supplemented with 50% of their recommended Cu requirements, could be used under normal housing temperature to enhance the birds' immune response, and during HS to lower heat stress-induced degenerative changes depending on the magnitude of the HS.

Poultry rearing on perforated plastic floors and the effect on air quality, growth performance, and carcass injuries - Experiment 2: Heat stress situation

Previously, we reported the effect of rearing conditions (plastic floors and air quality) on carcass injury development of broiler chickens at thermal comfort. In this study, the same rearing conditions were tested at thermal stress. The birds were reared in 2 climatic chambers, and the experiment followed a completely randomized design with one factor, flooring material: wood shaving or perforated plastic. The birds were divided into 16 experimental pens, being 8 females and 8 males. The studied parameters were the same as the previous study (ammonia concentration, carbon dioxide, performance, carcass yield, and variability, and scores of hygiene, gait and chest, and hocks and footpad lesions). Higher ammonia (15 ppm vs. 4 ppm) and carbon dioxide (1,000 ppm vs. 850 ppm) concentration was seen at d 42 for the wood shavings floor as compared to the perforated plastic floor, respectively. Regarding gender, males had better performance than females at 42 d of age on both floor types. Males reared on wood shavings showed a higher meat production (29.049 kg/m2) than females (24.700 kg/m2). There were observed breast lesion incidences of 10.4% (score 1) in males reared on the plastic floor, as well higher incidence of hock injury and footpad dermatitis. Chickens reared on plastic flooring showed better hygiene than chickens reared on wood shavings. Our findings revealed that the use of perforated plastic flooring in a heat stress situation can improve the air quality (less CO2 and NH3 concentration) and bird cleanliness. On the other hand, chickens are more susceptible to develop lesions in the breast, hock, and footpad. We conclude that the use of plastic flooring in heat stress conditions needs more attention, since chickens are more susceptible to develop lesions on the carcass, being a source of pain, impairing bird wellbeing and causing losses in meat production.

Ammonia production in poultry houses can affect health of humans, birds, and the environment-techniques for its reduction during poultry production

Due to greater consumption of poultry products and an increase in exports, more poultry houses will be needed. Therefore, it is important to investigate ways that poultry facilities can coexist in close proximity to residential areas without odors and environmental challenges. Ammonia (NH₃) is the greatest concern for environmental pollution from poultry production. When birds consume protein, they produce uric acid, ultimately converted to NH₃ under favorable conditions. Factors that increase production include pH, temperature, moisture content, litter type, bird age, manure age, relative humidity, and ventilation rate (VR). NH₃ concentration and emissions in poultry houses depend on VR; seasons also have effects on NH₃ production. Modern ventilation systems can minimize NH₃ in enclosed production spaces quickly but increase its emissions to the environment. NH₃ adversely affects the ecosystem, environment, and health of birds and people. Less than 10 ppm is the ideal limit for exposure, but up to 25 ppm is also not harmful. NH₃ can be minimized by housing type, aerobic and anaerobic conditions, manure handling practices, litter amendment, and diet manipulation without affecting performance and production. Antibiotics can minimize NH₃, but consumers have concerns about health effects. Administration of probiotics seems to be a useful replacement for antibiotics. More studies have been conducted on broilers, necessitating the need to evaluate the effect of probiotics on NH₃ production in conjunction with laying hen performance and egg quality. This comprehensive review focuses on research from 1950 to 2018.

Poultry rearing on perforated plastic floors and the effect on air quality, growth performance, and carcass injuries-Experiment 1: Thermal Comfort

The present study investigated the use of perforated plastic floors in the rearing of male and female poultry under thermal comfort conditions. The study was conducted in 2 climate chambers, in one was conventional poultry litter (wood shavings) and in the other was a perforated plastic floor. The experimental design was a completely randomized design with the factors wood shavings and plastic floor. In each chamber, the animals were divided into 16 experimental pens (8 with males and 8 with females) with a density of 12 birds/m2. The poultry rearing effect was evaluated in terms of air quality (% concentration of ammonia [NH3] and carbon dioxide [CO2]); broiler performance, e.g., weight gain (kg), feed intake (kg), feed conversion, carcass yield and parts (%), meat production (kg/m2), and viability (% of live birds at d 42); scores of hygiene and mobility; and injuries in the chest, hocks, and footpads. Treatments affected air quality, with higher concentrations of NH3 on d 42 (25 ppm vs. 2 ppm) and CO2 (1,400 ppm vs. 1,000 ppm) for wood shavings than for perforated plastic floor, respectively. Males showed a better performance (weight gain, feed intake and feed conversion) than females on d 42 in both floor types (wood shavings and plastic floor). Males reared on wood shavings showed a higher meet production (35.992 kg/m2) than females (32.257 kg/m2). On the plastic floor, males showed a better viability (100%) than females (94.05%), as well better meet production for males (38.55 kg·m-2) than females (31.64 kg/m2). There was no incidence of breast lesions in any of the studied systems. The birds reared on the plastic floor had better hygiene scores and lower hock injury rates than birds reared in the wood shavings chambers. The results of the present study show that the use of perforated plastic floors in chicken farming is an efficient method, which promotes a better-quality environment, superior production rates, and reduced incidence of injuries.

Administration of Bacillus Amyloliquefaciens and Saccharomyces Cerevisiae as Direct-Fed Microbials Improves Intestinal Microflora and Morphology in Broiler Chickens

This study was conducted to investigate the effects of Bacillus amyloliquefaciens (BA) and Saccharomyces cerevisiae (SC) as directed-fed microbials on performance, intestinal microflora, and intestinal morphology in broiler chickens. A total of four hundred one-day-old broiler chickens were randomly divided into 16 pens of 25 chickens each, and every treatment had 4 replicated pens with two pens of males and females respectively. A formulated corn-soybean meal based control diets and experimental diets, including 0.1% BA (1×10⁷ colony-forming units (CFU)/kg), the mixture of 0.05% BA (5×10⁶ CFU/kg) and 0.05% SC (5×10⁶ CFU/kg), and 10 ppm antibiotic (avilamycin), were fed for 5 weeks. The results showed no significant difference in the growth performance among all treatments. Supplementation of the mixture of BA and SC increased acetate and propionate and decreased the E. coli in ceca compared to control and antibiotic treatment. The treatments with antibiotic, BA, and the mixture of BA and SC compared to control treatment increased villus height / crypt depth ratio and decreased ammonia in excreta. In addition, supplementation of BA and the mixture of BA and SC compared to antibiotic treatment increased serum high-density lipoprotein, and decreased serum glutamic-oxaloacetic transaminase, respectively. In conclusion, supplementation of the mixture of BA and SC was better than added BA only, and the mixed probiotics product could potentially alter the use of avilamycin in broiler diets.

Effects of two litter amendments on air NH3 levels in broiler closed-houses

OBJECTIVE

High NH₃ emissions from poultry houses are reported to have negative impacts on health, welfare and safety of birds and humans, and on the environment. Objective of the present study was to determine the effects of two litter amendments on the NH₃ levels in broiler closed houses under hot-humid conditions.

METHODS

Giving a completely randomize design, nine closed houses, each housed 32,500 birds on paddy husk litter, were randomly allocated into two treatment (Mizuho; a bacterial culture mix and Rydall OE; an enzymatic biocatalyst) and control groups. NH₃ levels were determined thrice a day (0600, 1200, and 1800 h), at three heights from the litter surface (30, 90, and 150 cm), at 20 predetermined locations of a house, from day 1 to 41.

RESULTS

Rydall significantly reduced the NH₃ level compared to control and Mizuho. NH₃ levels at 30 cm were significantly higher than that of 90 and 150 cm. The NH₃ levels at 30 cm height were higher than 25 ppm level from day 9, 11, and 13 in Mizuho, control, and Rydall groups, respectively to day 41. NH₃ levels at 150 cm height were higher than maximum threshold limit of 50 ppm for human exposure from day 12, 14, and 15 in Mizuho, control, and Rydall groups, respectively to day 33. Being significantly different among each other, the NH₃ level was highest and lowest at 0600 and 1800 h. Litter amendments had no significant effects on growth performance. Rydall significantly increased the litter N content on day 24.

CONCLUSION

It was concluded that the NH₃ levels of closed house broiler production facilities under tropical condition are so high that both birds and workers are exposed to above recommended levels during many days of the growing period. Compared to microbial culture, the enzymatic biocatalyst was found to be more effective in reducing NH₃ level.

Transcriptome Profile Analysis of Breast Muscle Tissues from High or Low Levels of Atmospheric Ammonia Exposed Broilers (Gallus gallus)

Atmospheric ammonia is a common problem in poultry industry. High concentrations of aerial ammonia cause great harm to broilers' health and production. For the consideration of human health, the limit exposure concentration of ammonia in houses is set at 25 ppm. Previous reports have shown that 25 ppm is still detrimental to livestock, especially the gastrointestinal tract and respiratory tract, but the negative relationship between ammonia exposure and the tissue of breast muscle of broilers is still unknown. In the present study, 25 ppm ammonia in poultry houses was found to lower slaughter performance and breast yield. Then, high-throughput RNA sequencing was utilized to identify differentially expressed genes in breast muscle of broiler chickens exposed to high (25 ppm) or low (3 ppm) levels of atmospheric ammonia. The transcriptome analysis showed that 163 genes (fold change ≥ 2 or ≤ 0.5; P-value < 0.05) were differentially expressed between Ammonia25 (treatment group) and Ammonia3 (control group), including 96 down-regulated and 67 up-regulated genes. qRT-PCR analysis validated the transcriptomic results of RNA sequencing. Gene Ontology (GO) functional annotation analysis revealed potential genes, processes and pathways with putative involvement in growth and development inhibition of breast muscle in broilers caused by aerial ammonia exposure. This study facilitates understanding of the genetic architecture of the chicken breast muscle transcriptome, and has identified candidate genes for breast muscle response to atmospheric ammonia exposure.

High concentrations of atmospheric ammonia induce alterations of gene expression in the breast muscle of broilers (Gallus gallus) based on RNA-Seq

BACKGROUND

High concentrations of atmospheric ammonia are one of the key environmental stressors affecting broiler production performance, which causes remarkable economic losses as well as potential welfare problems of the broiler industry. Previous reports demonstrated that high levels of ammonia altered body fat distribution and meat quality of broilers. However, the molecular mechanisms and metabolic pathways in breast muscle altered by high concentrations of ambient ammonia exposure on broilers are still unknown.

RESULTS

This study utilized RNA-Seq to compare the transcriptomes of breast muscles to identify differentially enriched genes in broilers exposed to high and low concentrations of atmospheric ammonia. A total of 267 promising candidate genes were identified by differential expression analysis, among which 67 genes were up-regulated and 189 genes were down-regulated. Bioinformatics analysis suggested that the up and down-regulation of these genes were involved in the following two categories of cellular pathways and metabolisms: Steroid biosynthesis (gga00100) and peroxisome proliferator-activated receptor (PPAR) signaling pathway (gga03320), which both participated in the lipid metabolism processes.

CONCLUSIONS

This study suggests that longtime exposure to high concentrations of aerial ammonia can change fat content in breast muscle, meat quality and palatability via altering expression level of genes participating in important lipid metabolism pathways. These findings have provided novel insights into our understanding of molecular mechanisms of breast muscles exposed to ammonia in broilers. This study provides new information that could be used for genetic breeding and nutritional intervention in production practice of broilers industry in the future.