Cytokine profiles, apoptosis and pathology of experimental Pasteurella multocida serotype A1 infection in mice

Pasteurella multocida activates Rassf1-Hippo-Yap pathway to induce pulmonary epithelial apoptosis

Pasteurella multocida is an opportunistic zoonotic pathogen that primarily causes fatal respiratory diseases, such as pneumonia and respiratory syndromes. However, the precise mechanistic understanding of how P. multocida disrupts the epithelial barrier in mammalian lung remains largely unknown. In this study, using unbiased RNA-seq analysis, we found that the evolutionarily conserved Hippo-Yap pathway was dysregulated after P. multocida infection. Given the complexity of P. multocida infection associated with lung injury and systemic inflammatory processes, we employed a combination of cell culture models, mouse models, and rabbit models to investigate the dynamics of the Hippo-Yap pathway during P. multocida infection. Our findings reveal that P. multocida infection activates the Hippo-Yap pathway both in vitro and in vivo, by upregulating the upstream factors p-Mst1/2, p-Lats1, and p-Yap, and downregulating the downstream effectors Birc5, Cyr61, and Slug. Conversely, pharmacological inhibition of the Hippo pathway by XMU-MP-1 significantly rescued pulmonary epithelial cell apoptosis in vitro and reduced lung injury, systemic inflammation, and mouse mortality in vivo. Mechanistic studies revealed that P. multocida induced up-regulation of Rassf1 expression, and Rassf1 enhanced Hippo-Yap pathway through phosphorylation. Accordingly, in vitro knockdown of Rassf1 significantly enhanced Yap activity and expression of Yap downstream factors and reduced apoptosis during P. multocida infection. P. multocida-infected rabbit samples also showed overexpression of Rassf1, p-Lats1, and p-Yap, suggesting that P. multocida activates the Rassf1-Hippo-Yap pathway. These results elucidate the pathogenic role of the Rassf1-Hippo-Yap pathway in P. multocida infection and suggest that this pathway has the potential to be a drug target for the treatment of pasteurellosis.

Differential responses of monocyte-derived macrophages from Theileria orientalis infected carrier cattle to Pasteruella multocida B:2 infection and latex beads: A preliminary study

This study aims to evaluate the responses of peripheral blood monocyte-derived macrophages (PBMDMs) from Theileria orientalis carrier cattle following exposure to Pasteruella multocida B:2 (PM B:2) and latex beads. Twenty-six male crossbred Kedah-Kelantan (KK) cattle were sampled for this study and quantitative PCR (qPCR) was employed in the detection of T. orientalis MPSP gene. Bactericidal assay using a 10:1 multiplicity of infection was performed to measure the phagocytosis and intracellular killing of PM B:2 by PBMDMs. The cell cultures were inoculated with 107 cfu/mL of PM B:2 and incubated in a humidified incubator. The absence of clinical signs, previous history of T. orientalis infection and an MPSP gene copy number below 15,000 GC/μL suggest that the cattle were asymptomatic chronic carriers. A non-significant phagocytic and mean cell death rates were observed in the PBMDMs of T. orientalis positive cattle relative to clinically healthy cattle (CHC) (p > 0.05). The PBMDMs of T. orientalis positive cattle had the lowest mean rate of intracellular killing relative to the CHC at the 30th minute post-infection only (p < 0.05). Exposure to latex beads caused an increase in the appearance of multinucleated macrophages following incubation of PBMDMs from T. orientalis positive cattle. Furthermore, the phagocytic index of PBMDMs of T. orientalis positive cattle were low or poor compared to that of CHC (p = 0.000). Therefore, our findings suggest that PBMDMs from cattle with chronic T. orientalis infection can efficiently phagocytise and kill PM: B2 but exhibited poor phagocytosis ability for foreign bodies despite appearance of multinucleated macrophages.

Chemical Characterisation, Antidiabetic, Antibacterial, and In Silico Studies for Different Extracts of Haloxylon stocksii (Boiss.) Benth: A Promising Halophyte

The objective of the study is to evaluate the chemical characterisation, and biological and in silico potential of Haloxylon stocksii (Boiss.) Benth, an important halophyte commonly used in traditional medicine. The research focuses on the roots and aerial parts of the plant and extracts them using two solvents: methanol and dichloromethane. Chemical characterisation of the extracts was carried out using total phenolic contents quantification, GC-MS analysis, and LC-MS screening. The results exhibited that the aerial parts of the plant have significantly higher total phenolic content than the roots. The GC-MS and LC-MS analysis of the plant extracts revealed the identification of 18 bioactive compounds in each. The biological evaluation was performed using antioxidant, antibacterial, and in vitro antidiabetic assays. The results exhibited that the aerial parts of the plant have higher antioxidant and in vitro antidiabetic activity than the roots. Additionally, the aerial parts of the plant were most effective against Gram-positive bacteria. Molecular docking was done to evaluate the binding affinity (BA) of the bioactive compounds characterised by GC-MS with diabetic enzymes used in the in vitro assay. The results showed that the BA of γ-sitosterol was better than that of acarbose, which is used as a standard in the in vitro assay. Overall, this study suggests that the extract from aerial parts of H. stocksii using methanol as a solvent have better potential as a new medicinal plant and can provide a new aspect to develop more potent medications. The research findings contribute to the scientific data of the medicinal properties of Haloxylon stocksii and provide a basis for further evaluation of its potential as a natural remedy.

Effects of Equol Supplementation on Growth Performance, Redox Status, Intestinal Health and Skeletal Muscle Development of Weanling Piglets with Intrauterine Growth Retardation

Animals with intrauterine growth retardation (IUGR) usually undergo injured postnatal growth and development during the early period after birth. Equol (Eq), an isoflavan produced by gut bacteria in response to daidzein intake, has various health benefits. Therefore, the objective of this study was to evaluate whether Eq supplementation can influence the growth performance, redox status, intestinal health and skeletal muscle development of weanling piglets with IUGR. A total of 10 normal-birth-weight (NBW) newborn female piglets and 20 newborn female piglets with IUGR were selected. After weaning at the age of 21 d, 10 NBW piglets and 10 IUGR piglets were allocated to the NBW group and IUGR group, respectively, and offered a basal diet. The other 10 IUGR piglets were allocated to the IUGR + Eq group and offered a basal diet with 50 mg of Eq per kg of diet. The whole trial lasted for 21 d. At the end of the feeding trial, all piglets were sacrificed for the collection of serum, intestinal tissues and skeletal muscles. Supplementation with Eq increased the average daily gain (ADG), average daily feed intake (ADFI), duodenal villus height to crypt depth ratio (V/C), jejunal villus height and V/C, but reduced the duodenal crypt depth in neonatal piglets with IUGR. Meanwhile, Eq supplementation elevated the activities of superoxide dismutase (SOD) and catalase (CAT) in the serum and duodenum and the activity of SOD in the jejunum, but lowered malondialdehyde (MDA) content in the serum, jejunum and ileum of piglets with IUGR. In addition, supplementation with Eq reduced diamine oxidase (DAO) activity and the levels of D-lactate and endotoxin in serum, and the tumor necrosis factor-α (TNF-α) level in jejunum and ileum, whereas the concentration of serum immunoglobulin G (IgG) and the mRNA levels of intestinal barrier-related markers in jejunum and ileum of IUGR piglets were increased. Furthermore, supplementation with Eq elevated the percentage of fast-fibers and was accompanied with higher mRNA expression of myosin heavy chain IIb (MyHC IIb) and lower mRNA levels in MyHC I in the longissimus thoracis (LT) muscle of IUGR piglets. In summary, Eq supplementation can promote antioxidant capacity, maintain intestinal health and facilitate skeletal muscle development, thus resulting in the higher growth performance of IUGR piglets.

Pmorf0222, a Virulence Factor in Pasteurella multocida, Activates Nuclear Factor Kappa B and Mitogen-Activated Protein Kinase via Toll-Like Receptor 1/2

Pasteurella multocida primarily causes hemorrhagic septicemia and pneumonia in poultry and livestock. Identification of the relevant virulence factors is therefore essential for understanding its pathogenicity. Pmorf0222, encoding the PM0222 protein, is located on a specific prophage island of the pathogenic strain C48-1 of P. multocida. Its role in the pathogenesis of P. multocida infection is still unknown. The proinflammatory cytokine plays an important role in P. multocida infection; therefore, murine peritoneal exudate macrophages were treated with the purified recombinant PM0222, which induced the secretion of tumor necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β) via the Toll-like receptor 1/2 (TLR1/2)-nuclear factor kappa B (NF-κB)/mitogen-activated protein kinase (MAPK) signaling and inflammasome activation. Additionally, the mutant strain and complemented strain were evaluated in the mouse model with P. multocida infection, and PM0222 was identified as a virulence factor, which was secreted by outer membrane vesicles of P. multocida. Further results revealed that Pmorf0222 affected the synthesis of the capsule, adhesion, serum sensitivity, and biofilm formation. Thus, we identified Pmorf0222 as a novel virulence factor in the C48-1 strain of P. multocida, explaining the high pathogenicity of this pathogenic strain.

Pathogenicity, colonization, and innate immune response to Pasteurella multocida in rabbits

BACKGROUND

Pasteurella multocida (P. multocida) infection can cause a series of diseases in different animals and cause huge economic losses to the breeding industry. P. multocida is considered to be one of the most significant pathogens in rabbits. In order to elucidate the pathogenic mechanism and innate immune response of P. multocida, an infection experiment was carried out in this study.

RESULTS

Our results showed that the clinical symptoms of rabbits were severe dyspnoea and serous nasal fluid. During the course of the disease, the deaths peaked at 2 days post infection (dpi) and mortality rate was 60%. The pathological changes of the lung, trachea, and thymus were observed. In particular, consolidation and abscesses appeared in lung. Histopathologic changes in rabbits showed edema, hemorrhage, and neutrophil infiltration in the lung. P. multocida can rapidly replicate in a variety of tissues, and the colonization in most of the tested tissues reached the maximum at 2 dpi and then decreased at 3 dpi. The number of P. multocida in lung and thymus remained high level at 3 dpi. Toll-like receptors 2 and 4 signaling pathways were activated after P. multocida infection. The expression of Il1β, Il6, Il8, and Tnf-α was significantly increased. The expression of most proinflammatory cytokines peaked at 2 dpi and decreased at 3 dpi, and the expression trend of cytokines was consistent with the colonization of P. multocida in rabbit tissues.

CONCLUSIONS

The P. multocida can rapidly replicate in various tissues of rabbit and cause bacteremia after infection. TLRs signaling pathways were activated after P. multocida infection, significantly inducing the expression of proinflammatory cytokines, which is might the main cause of respiratory inflammation and septicemia.

Up-Regulation of Interleukin-10 in Splenic Immune Response Induced by Serotype A Pasteurellamultocida

Pasteurella multocida (P. multocida) is an opportunistic pathogen that is common in livestock and poultry and leads to massive economic losses in the animal husbandry sector. In this study, we challenged mice with P. multocida strain HN02 by intraperitoneal injection and collected spleens to measure bacterial loads. We also performed histopathological analysis by hematoxylin and eosin (H&E) staining. Then we used RNA-sequencing (RNA-seq) to detect the mRNA expression levels in the mouse spleen and quantitative real-time PCR (qRT-PCR) to verify the sequencing data. Finally, we examined the effect of HN02 on anti-inflammatory cytokine interleukin-10 (IL-10) protein expression in the spleen through immunohistochemical analysis. The results showed that compared to those in the control group, the mouse spleens in the challenge group had lesions, and the average bacteria loads was (3.07 ± 1.09) × 10⁶ CFU (colony-forming unit)/g. The RNA-seq results determined 3653 differentially expressed genes (DEGs), and the qRT-PCR analysis revealed immune-related genes consistent with the expression trend in the sequencing data. The number and area of IL-10 positive cells substantially increased to resist inflammation in the challenge group. In conclusion, we analyzed the spleens of mice infected with P. multocida from multiple perspectives, and our findings lay a foundation for subsequent studies on the mechanism of pathogen-host interactions.

Effects of Pasteurella multocida on Histopathology, miRNA and mRNA Expression Dynamics in Lung of Goats

Pasteurella multocida (Pm) infection causes severe respiratory disease in goats. We investigated the effects of the Pm infection intratracheally on the histopathology, miRNA and mRNA expression dynamics in the lung of goats infected for 1, 2, 5 and 7 days. Pm infection caused fever, which significantly (p < 0.05) increased the body temperature of the goats from day 1 to 5. Haemotoxylin−eosin staining of the infected lung tissue showed characteristics of suppurative pneumonia with inflammatory cells infiltration and the lung structure destruction. During the Pm infection of the goats, compared with the control group, there were 3080, 3508, 2716 and 2675 differentially expressed genes and 42, 69, 91 and 108 significantly expressed miRNAs (|log2Fold Change| > 1, p < 0.05) in the Pm_d1, Pm_d2, Pm_d5 and Pm_d7 groups, respectively. Five miRNAs and nine immune-related genes were selected for confirmation by reverse transcription−polymerase chain reaction. The results indicated that the expression patterns of the miRNAs and genes were consistent with those determined by next-generation sequencing. The differentially expressed genes were enriched in cytokine−cytokine receptor interaction, cell adhesion molecules, complement and coagulation cascades, tight junction and phagosome Kyoto Encyclopedia of Genes and Genomes pathways and cytokine production, leukocyte migration, myeloid leukocyte migration, cell periphery, plasma membrane, extracellular region part, extracellular region and other Gene Ontology terms. The differentially expressed genes were mapped to marker genes in human and mouse lung cells. The results showed the presence of some marker genes of the immune cells. Compared with the CK group, five miRNAs and 892 common genes were differentially expressed in the Pm_d1, Pm_d2, Pm_d5 and Pm_d7 groups. The target relationships between the common 5 miRNAs and 892 differentially expressed genes were explored and the miRNAs involved in the host immune reaction may act through the target genes. Our study characterized goats’ reaction in the lung from histopathological and molecular changes upon Pm infection, which will provide valuable information for understanding the responses in goats during Pm infection.

How to Develop Strategies to Use Insects as Animal Feed: Digestibility, Functionality, Safety, and Regulation

Various insects have emerged as novel feed resources due to their economical, eco-friendly, and nutritive characteristics. Fish, poultry, and pigs are livestock that can feed on insects. The digestibility of insect-containing meals were presented by the species, life stage, nutritional component, and processing methods. Several studies have shown a reduced apparent digestibility coefficient (ADC) when insects were supplied as a replacement for commercial meals related to chitin. Although the expression of chitinase mRNA was present in several livestock, indigestible components in insects, such as chitin or fiber, could be a reason for the reduced ADC. However, various components can positively affect livestock health. Although the bio-functional properties of these components have been verified in vitro, they show positive health-promoting effects owing to their functional expression when directly applied to animal diets. Changes in the intestinal microbiota of animals, enhancement of immunity, and enhancement of antibacterial activity were confirmed as positive effects that can be obtained through insect diets. However, there are some issues with the safety of insects as feed. To increase the utility of insects as feed, microbial hazards, chemical hazards, and allergens should be regulated. The European Union, North America, East Asia, Australia, and Nigeria have established regulations regarding insect feed, which could enhance the utility of insects as novel feed resources for the future.

Melatonergic signalling instructs transcriptional inhibition of IFNGR2 to lessen interleukin‐1β‐dependent inflammation

Background

Immunotransmitters (e.g., neurotransmitters and neuromodulators) could orchestrate diverse immune responses; however, the elaborated mechanism by which melatonergic activation governs inflammation remains less defined.

Methods

Primary macrophages, various cell lines, and Pasteurella multocida (PmCQ2)‐infected mice were respectively used to illustrate the influence of melatonergic signalling on inflammation in vitro and in vivo. A series of methods (e.g., RNA‐seq, metabolomics, and genetic manipulation) were conducted to reveal the mechanism whereby melatonergic signalling reduces macrophage inflammation.

Results

Here, we demonstrate that melatonergic activation substantially lessens interleukin (IL)‐1β‐dependent inflammation. Treatment of macrophages with melatonin rewires metabolic program, as well as remodels signalling pathways which depends on interferon regulatory factor (IRF) 7. Mechanistically, melatonin acts via membrane receptor (MT) 1 to increase heat shock factor (Hsf) 1 expression through lowering the inactive glycogen synthase kinase (GSK3) β, thereby transcriptionally inhibiting interferon (IFN)‐γ receptor (IFNGR) 2 and ultimately causing defective canonical signalling events [Janus kinase (JAK) 1/2‐signal transducer and activator of transcription (STAT) 1‐IRF7] and lower IL‐1β production in macrophages. Moreover, we find that melatonin amplifies host protective responses to PmCQ2 infection‐induced pneumonia.

Conclusions

Our conceptual framework provides potential therapeutic targets to prevent and/or treat inflammatory diseases associating with excessive IL‐1β production.

Effects of Melatonin Supplementation during Pregnancy on Reproductive Performance, Maternal-Placental-Fetal Redox Status, and Placental Mitochondrial Function in a Sow Model

Melatonin (MT) is a bio-antioxidant that has been widely used to prevent pregnancy complications, such as pre-eclampsia and IUGR during gestation. This experiment evaluated the impacts of dietary MT supplementation during pregnancy on reproductive performance, maternal-placental-fetal redox status, placental inflammatory response, and mitochondrial function, and sought a possible underlying mechanism in the placenta. Sixteen fifth parity sows were divided into two groups and fed each day of the gestation period either a control diet or a diet that was the same but for 36 mg of MT. The results showed that dietary supplementation with MT increased placental weight, while the percentage of piglets born with weight < 900 g decreased. Meanwhile, serum and placental MT levels, maternal-placental-fetal redox status, and placental inflammatory response were increased by MT. In addition, dietary MT markedly increased the mRNA levels of nutrient transporters and antioxidant-related genes involved in the Nrf2/ARE pathway in the placenta. Furthermore, dietary MT significantly increased ATP and NAD+ levels, relative mtDNA content, and the protein expression of Sirt1 in the placenta. These results suggested that MT supplementation during gestation could improve maternal-placental-fetal redox status and reproductive performance by ameliorating placental antioxidant status, inflammatory response, and mitochondrial dysfunction.

A water-soluble β-glucan improves growth performance by altering gut microbiome and health in weaned pigs

Beta-glucan has been shown to have a beneficial effect on gastrointestinal health. This experiment was conducted to investigate the effects of β-glucan isolated from Agrobacterium sp. ZX09 on growth performance and intestinal health of weaning pigs. A total of 108 weaned pigs (21 d of age; 6.05 ± 0.36 kg) were randomly divided into 3 groups (6 pens/group; 6 pigs/pen), and the groups were each treated with the following diets: 1) basal diet, 2) basal diet supplemented with 20 mg/kg olaquindox, 3) basal diet supplemented with 200 mg/kg β-glucan, for 21 d. Compared with the control group, pigs fed with 200 mg/kg β-glucan had greaterBW, average daily gain and duodenal villus height to crypt depth ratio (P < 0.05). Olaquindox increased the duodenal or jejunal villus height of pigs compared with β-glucan. Compared with the control group, β-glucan tended to increase the occludin mRNA expression in the jejunum (0.05 < P < 0.10). Beta-glucan enriched the beneficial microbiota in the ileum of pigs (P < 0.05). In conclusion, β-glucan may promote growth performance by improving intestinal health and increasing beneficial microbiota of weaned pigs. The study results will provide valuable theoretical guidance for the utilization of β-glucan in weaned pigs.

Supplementing daidzein in diets improves the reproductive performance, endocrine hormones and antioxidant capacity of multiparous sows

Certain hormones play important roles in modulating mammalian reproductive behaviour. Daidzein is a well-known isoflavonic phytoestrogen that possesses oestrogenic activity. This study was conducted to probe the effects of daidzein supplementation in gestation diets on the reproductive performance in sows. A total of 120 multiparous sows (Landrace × Yorkshire) were randomly assigned to 2 groups (n = 60) and fed either a base diet (control) or one containing 200 mg/kg daidzein during gestation. We discovered that daidzein supplementation significantly increased the total number of piglets born per litter and number of piglets born alive per litter (P < 0.05), decreased the farrowing time (P < 0.05) and increased the serum oestrogen and progesterone concentrations (P < 0.05) at 35 d of gestation. Moreover, serum immunoglobulin G (IgG) concentration and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were higher in the daidzein-treated group than in the control group at 35 d of gestation (P < 0.05). Daidzein increased the serum SOD activity and total anti-oxidative capacity (T-AOC) at 85 d of gestation (P < 0.05). Interestingly, daidzein elevated the expression levels of the sodium-coupled neutral amino acid transporter 1 (SLC38A1) and insulin-like growth factor 1 (IGF-1) genes in the placenta (P < 0.05). These results suggest that daidzein ingestion could improve sow reproductive performance by changing serum hormones, elevating anti-oxidative capacity and up-regulating critical functional genes in the placenta.

The effect of carbohydrates on the adherence of Pasteurella multocida to the nasal respiratory epithelium

Pasteurella multocida subsp. multocida is responsible for different diseases that generate great economic losses in farm animal. The effectiveness of immunization against those bacteria are variable and the use of antibiotics is questioned; for that reason, we investigated the potential inhibitory effect of different carbohydrates on the adherence in vivo of P. multocida to the rabbit respiratory epithelium as an alternative for the prevention of respiratory infections. Rabbits were intranasally and intratracheally inoculated with a solution containing 200 µl of 1x107 CFU of P. multocida that was previously mixed with 250 µg /200 µl of N-acetylglucosamine, alphamethylglucoside, alphamethylmannoside, N-acetylgalactosamine or sialic acid. The animals that received N-acetylglucosamine, alphamethylglucoside or alphamethylmannoside individually or a mixture of these three carbohydrates plus the bacterium, showed a significant decrease (P <0.05) of the clinical symptoms, microscopic and macroscopic lesions in the nasal septa and in the lungs; also, the number of adhered bacteria to the nasal epithelium were also significantly reduced. This research demonstrates for the first time that such an approach could convert into a method for prevention of P. multocida infection in rabbits that is ecologically and economically safe and effective.

The immune response and protective efficacy of a potential DNA vaccine against virulent Pasteurella multocida

Background

Pasteurella multocida is the main cause of several infections of farm animals, and the immunity gained from commercial vaccines is for the short term only and needs to be routinely administered, so work on new vaccines against virulent P. multocida is crucial.

Results

In this study, the OmpH gene was amplified from ten P. multocida strains, and the PCR products were sequenced and analyzed. The results of RFLP analysis of OmpH gene digested by MspI enzyme showed that all of ten strains examined possessed one restriction site and two fragments, 350 and 650 bp. The OmpH sequence of strain No. 10 was cloned into bacterial expression vector pUCP24, and the recombinant pUCP24-OmpH was expressed in E. coli DH5α. Serum samples obtained from the ELISA test from a group of vaccinated rats indicate that the antibodies were present at high titer in immunized rats and can be tested as a vaccine candidate with a challenge.

Conclusions

In rats infected with the DNA vaccine and inactivated vaccine, a significant increase in serum antibody levels was observed. In addition, the DNA vaccine provided the vaccinated rats with partial protection; however, the protective efficacy was greater than that offered by the live attenuated vaccine. This successful recombinant vaccine is immunogenic and may potentially be used as a vaccine in the future.

Biomarkers, immune responses and cellular changes in vaccinated and non-vaccinated goats during experimental infection of M. haemolytica A2 under tropical conditions

BACKGROUND

We investigated the biomarkers, immune responses and cellular changes in vaccinated and non-vaccinated goats experimentally challenged with M. haemolytica serotype A2 under rainy and hot tropical conditions. A total of twenty-four clinically healthy, non-pregnant, female goats randomly allocated to 2 groups of 12 goats each were used for the study. The 12 goats in each season were subdivided into three groups (n = 4), which served as the control (G-NEG), non-vaccinated (G-POS), and vaccinated (G-VACC). In week-1, the G-VACC received 2 mL of alum-precipitated pasteurellosis vaccine while G-POS and G-NEG received 2 ml of sterile PBS. In week 2, the G-POS and G-VACC received 1 mL intranasal spray containing 10⁵ CFU of M. haemolytica serotype A2. Inoculation was followed by daily monitoring and weekly bleeding for eight weeks to collect data and serum for biomarkers and immune responses using commercial ELISA test kits. The goats were humanely euthanised at the end of the experiments to collect lungs and the submandibular lymph nodes tissue samples for gross and histopathological examinations.

RESULTS

Regardless of the season, we have observed a significant (p < 0.05) increase in serum concentrations of acute-phase proteins (haptoglobin, serum amyloid A), proinflammatory cytokines (interleukine-1β, interleukin-6), antibodies (immunoglobulin M, immunoglobulin G), and stress markers (cortisol and heat shock protein 70) in the G-POS goats compared to G-VACC and G-NEG. With regards to seasons, there was a significantly (p < 0.05) higher serum concentration with 1.5, 2 and 1-folds increase in the serum interleukin (IL)-1β, cortisol, and heat shock protein (HSP)-70 in the G-POS during rainy compared to the hot season. Histopathology of the lungs in G-POS goats revealed inflammatory cell infiltration, degeneration, haemorrhage/congestion, and pulmonary oedema in the alveoli spaces; thickening of the interstitium, and desquamation of bronchiolar epithelium. Cellular changes in the lymph node were characterized by a marked hypercellularity in G-POS goats.

CONCLUSION

Host responses to pneumonic mannheimiosis based on increased serum levels of biomarkers (cortisol, HSP70, IL-1β and IL-6) and severe cellular changes seen in the lungs and lymph nodes of G-POS goats compared to vaccinated goats and control group are influenced by the high environmental humidity recorded in the rainy season. Increased relative humidity in the rainy season is a significant stress factor for the higher susceptibility and severity of pneumonic mannheimiosis of goats in the tropics. Vaccination of goats using the alum precipitated Pasteurella multocida vaccine before the onset of the rainy season is recommended to minimise mortality due to potential outbreaks of pneumonia during the rainy season.

Effect of dietary pyrroloquinoline quinone disodium in sows on intestinal health of the offspring

The objective of this study was to investigate the effects of dietary pyrroloquinoline quinone disodium (PQQ·Na2) supplementation in sows during gestation and lactation on intestinal health in offspring. A total of 40 cross-bred (landrace × large white crossed with Duroc boar) multiparity gestation sows with an average parity of 4.3 were used in this study. Forty sows were allotted to 2 dietary treatments after breeding. One group was the control sows, which were fed a corn-soybean meal control diet (Con treatment, n = 20), and the other group was the treatment sows fed a control diet with 20 mg kg-1 PQQ·Na2 after breeding and through gestation and lactation (PQQ treatment, n = 20). The activities of SOD and GSH-Px were significantly (P < 0.05) increased by PQQ·Na2 supplementation, and MDA activity was decreased (P < 0.05) in the plasma of piglets. CAT, SOD and GSH-Px activities were significantly (P < 0.05) increased, and MDA activity was decreased (P < 0.05) in the small intestine of piglets. The mRNA expression levels of SOD1, CAT and MGST1 in the jejunum were increased in newborn piglets (P < 0.05), and the mRNA expression levels of HO1, SOD1, CAT, SOD2, GPX4, GPX1 and GCLC in the jejunum were increased in weaned piglets (P < 0.05). The mRNA expression of ZO-1 was increased (P < 0.05) in the jejunum of newborn piglets, and the mRNA expression of Occludin and ZO-1 was increased (P < 0.05) in the jejunum of weaned piglets. The villous height of the duodenum and jejunum of weaned piglets was increased (P < 0.05) by dietary PQQ·Na2. In weaned piglets, Bacteroidetes and Firmicutes were the most prevalent phyla in both the Con and PQQ·Na2 treatment groups, and the most prevalent genera were Alloprevotella and Bacteroides. At the phylum level, the abundance of Firmicutes was significantly increased (P < 0.05), and the abundance of Proteobacteria was significantly decreased (P < 0.05). At the genus level, the abundance of Alloprevotella was significantly increased (P < 0.05), and the abundance of Actinobacillus and Escherichia was decreased (P < 0.05). In conclusion, dietary supplementation with PQQ·Na2 in sows during gestation and lactation had positive effects on intestinal health in offspring.

Transcriptomic Analysis of Chicken Lungs Infected With Avian and Bovine Pasteurella multocida Serotype A

Pasteurella multocida (P. multocida) is a common animal pathogen responsible for many animal diseases. Strains from different hosts exhibit disparate degrees of effect in other species. Here, we characterize an avian P. multocida serogroup A strain (PmQ) showing high lethality to chickens and a bovine P. multocida serogroup A strain (PmCQ2) with no lethality to chickens. We used RNA-seq to profile the transcriptomes of chicken lungs infected with PmQ and PmCQ2. A total of 1,649 differentially expressed genes (DEGs) due to PmQ infection (831 upregulated genes and 818 downregulated genes) and 1427 DEGs (633 upregulated genes and 794 downregulated genes) due to PmCQ2 infection were identified. Functional analysis of these DEGs demonstrated that the TNF signaling pathway, the toll-like receptor signaling pathway, complement and coagulation cascades, and cytokine–cytokine receptor interaction were both enriched in PmQ and PmCQ2 infection. STAT and apoptosis signaling pathways were uniquely enriched by PmQ infection, and the NOD-like receptor signaling pathway was enriched only by PmCQ2 infection. Cell-type enrichment analysis of the transcriptomes showed that immune cells, including macrophages and granulocytes, were enriched in both infection groups. Collectively, our study profiled the transcriptomic response of chicken lungs infected with P. multocida and provided valuable information to understand the chicken responses to P. multocida infection.

Ultrastructural changes in endothelial cells of buffaloes following in-vitro exposure to Pasteurella multocida B:2

BACKGROUND

Pasteurella multocida B:2 causes haemorrhagic septicaemia in cattle and buffaloes. However, buffaloes are found to be more susceptible to the infection than cattle. Upon infection, the pathogen rapidly spread from the respiratory tract to the blood circulation within 16-72 h, causing septicaemia. So far, limited study has been conducted to evaluate the response of endothelial cells of buffalo towards P. multocida B:2 and its lipopolysaccharide (LPS). This study aimed to evaluate the ultrastructural changes in the aortic endothelium of buffaloes (BAEC) following exposure to P. multocida B:2 and its endotoxin. The endothelial cells were harvested from the aorta of healthy buffaloes and were prepared as monolayer cell cultures. The cultures were divided into 3 groups before Group 1 was inoculated with 10⁷ cfu/ml of whole cell P. multocida B:2, Group 2 with LPS, which was extracted earlier from 10⁷ cfu/ml of P. multocida B:2 and Group 3 with sterile cell culture medium. The cells were harvested at 0, 6, 12, 18, 24, 36, and 48 h post-inoculation for assessment of cellular changes using transmission electron microscopy.

RESULTS

The BAEC of Groups 1 and 2 demonstrated moderate to severe endothelial lysis, suggestive of acute cellular injury. In general, severity of the ultrastructural changes increased with the time of incubation but no significant difference (p > 0.05) in the severity of the cellular changes between Groups 1 and 2 was observed in the first 18 h. The severity of lesions became significant (p < 0.05) thereafter. Both treated Groups 1 and 2 showed significantly (p < 0.05) more severe cellular changes compared to the control Group 3 from 6 h post-inoculation. The severity reached peak at the end of the study period with score 3 for Group 1 and score 2.8 for Group 2.

CONCLUSIONS

This study revealed that both whole cells P. multocida B:2 and LPS endotoxin showed similar moderate to severe cellular damage, but whole-cell P. multocida B:2 appeared to be more potent in causing much severe damage than LPS alone.

Modulation of Gut Microbiota, Short-Chain Fatty Acid Production, and Inflammatory Cytokine Expression in the Cecum of Porcine Deltacoronavirus-Infected Chicks

Porcine deltacoronavirus (PDCoV) is a novel swine enteropathogenic coronavirus that causes watery diarrhea and induces proinflammatory cytokine responses in piglets. Our previous research showed that the specific-pathogen-free (SPF) chicks exhibited mild diarrhea and low fecal viral shedding, along with cecum lesions after PDCoV infection. Disturbances in the homeostasis of the gut microbiota have been associated with various diseases. We aimed to explore the effects of PDCoV infection on chick gut microbiota, short-chain fatty acid (SCFAs) production, and inflammatory cytokine expression in chicks, and also to investigate the relationship between gut microbiota and SCFAs or inflammatory cytokine expression of the PDCoV-infected chicks. Results obtained using 16S rRNA sequencing showed that infection with PDCoV strain HNZK-02 significantly altered the composition of chick gut microbiota, with the reduced abundance of Eisenbergiella and Anaerotruncus genera at 5 days post-inoculation (dpi) (P < 0.05), and an increased abundance of Alistipes genus at 17 dpi (P < 0.05). The production of SCFAs in the cecum of PDCoV HNZK-02–infected chicks, including acetic acid, propionic acid, and butyric acid, decreased in all cases. The expression of inflammatory cytokines (interferon-γ, tumor necrosis factor-α, and interleukin-10) was increased in the cecum tissue and serum of the PDCoV HNZK-02–infected chicks when detected by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Further analysis showed significant correlation between bacterial genera and SCFAs or inflammatory cytokines expression in cecum of the PDCoV infected chicks. These findings might provide new insight into the pathology and physiology of PDCoV in chicks.

High- and low-virulent bovine Pasteurella multocida induced differential NLRP3 inflammasome activation and subsequent IL-1β secretion

Pasteurella multocida is a gram-negative bacterial pathogen, which causes a large number of diseases in mammals, birds and human. Although the bacterium has been known for decades, the pathogenesis and the mechanisms of P. multocida induced host immunity are poorly understood. Recently, we have reported that nucleotide-binding oligomerization domain-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome plays an important role in caspase-1 activation and IL-1β secretion in macrophages infected with P. multocida. In this study, the inflammasome activation and IL-1β secretion were further demonstrated by using high- and low-virulent bovine P. multocida isolates. The results showed that, comparing with macrophages infected with the high-virulent PmCQ2 isolates, the low-virulent PmCQ6 induced higher levels of NLRP3 transcription, caspase-1 activation and mature IL-1β secretion. Furthermore, the capsule of the high-virulent PmCQ2 was much thicker than that of low-virulent PmCQ6, which indicating that capsular thickness might influence the bacteria colonization and NLRP3 inflammasome activation. The results suggested that differences in maturation of IL-1β in macrophages upon high- and low- virulent P. multocida infection are critically dependent on the differential activation of NLRP3 inflammasome. This study provided more understanding for the host immune responses induced by P. multocida and further extended the knowledge of P. multocida virulence from the view of host innate immunity.

Defatted Rice Bran Supplementation in Diets of Finishing Pigs: Effects on Physiological, Intestinal Barrier, and Oxidative Stress Parameters

Simple Summary

Most studies on dietary fiber mainly focus on the digestibility of feed nutrients and microbial flora, etc. However, insufficient attention has been paid to the regulation of immune and oxidative stress of the intestinal tract by dietary fiber. This study investigated the effects of varying levels of defatted rice bran replacing corn on physiological, intestinal barrier, and oxidative stress parameters in finishing pigs. Based on the current findings, a high diet of rice bran will not only reduce the level of inflammatory factors in the peripheral blood of finishing pigs, but also enhance the healthy level of the colon through mucin2 and keap1-Nrf2 pathways. Our results can be used as reference for dietary rice bran to improve intestinal health in finishing pigs.

Abstract

Rice bran is a waste product with low cost and high fiber content, giving it an added advantage over corn and soybean meal, which have to be purchased and always at a relatively higher cost. Under the background of increased attention to sustainable agriculture, it is significant to find alternative uses for this byproduct. A total of 35 finishing pigs were allotted to five dietary treatments: a control group with basal diet and four experimental diets where corn was equivalently substituted by 7%, 14%, 21%, and 28% defatted rice bran (DFRB), respectively. With increasing levels of DFRB, the neutrophil to lymphocyte ratio (NLR) linearly decreased (p < 0.05). In the jejunum, the mRNA level of nuclear factor erythroid-2 related factor-2 (Nrf2) exhibited a quadratic response (p < 0.01) with incremental levels of DFRB. In the colon, the mRNA levels of mucin 2 (MUC2), Nrf2, and NAD(P)H: quinone oxidoreductase 1 (NQO1) were upregulated (linear, p < 0.05) and heme oxygenase-1 (HO-1) was upregulated (linear, p < 0.01). Overall, using DFRB to replace corn decreased the inflammatory biomarkers of serum and showed potential function in modulating the intestinal barrier by upregulating the mRNA expression levels of MUC2 and downregulating that of Nrf2, NQO1, and HO-1 in the colon.

Fecal bacteria and metabolite responses to dietary lysozyme in a sow model from late gestation until lactation

Lysozyme (LZM) is a natural anti-bacterial protein that is found in the saliva, tears and milk of all mammals including humans. Its anti-bacterial properties result from the ability to cleave bacterial cell walls, causing bacterial death. The current study was conducted to investigate the effects of dietary LZM on fecal microbial composition and variation in metabolites in sow. The addition of LZM decreased the fecal short-chain fatty acids (SCFAs). Zonulin and endotoxin in the serum, and feces, were decreased with lysozyme supplementation. Furthermore, fecal concentrations of lipocalin-2 and the pro-inflammatory cytokine TNF-α were also decreased while the anti-inflammatory cytokine IL-10 was increased by lysozyme supplementation. 16S rRNA gene sequencing of the V3-V4 region suggested that fecal microbial levels changed at different taxonomic levels with the addition of LZM. Representative changes included the reduction of diversity between sows, decreased Bacteroidetes, Actinobacteria, Tenericutes and Spirochaetes during lactation as well as an increase in Lactobacillus. These findings suggest that dietary lysozyme supplementation from late gestation to lactation promote microbial changes, which would potentially be the mechanisms by which maternal metabolites and inflammatory status was altered after LZM supplementation.

Pasteurella multocida specific bacteriophage suppresses P. multocida-induced inflammation: identification of genes related to bacteriophage signaling by Pasteurella multocida-infected swine nasal turbinate cells

BACKGROUND

Although Pasteurella multocida is highly prevalent pathogen in animals and plays an important role in swine respiratory diseases, only a few studies on the use of bacteriophages specific to Pasteurella multocida disease have been reported.

OBJECTIVE

The object of this study was to investigate the therapeutic effect of specific P. multocida bacteriophages and to identify genes related to bacteriophage signaling utilizing RNA microarrays in swine nasal turbinate cells.

METHODS

Pas-MUP-1 phages were applied 24 h prior to P. multocida infection (1 × 10⁷ cfu/ml) at several concentrations of bacterial infection. Cells were incubated to detect cytokines and 24 h to detect mucin production. And real-time quantitative PCR was performed to examine related genes expression. To determine the change of total gene expression based on P. multocida and Pas-MUP-1 treatment, we performed RNA sequencing experiments.

RESULTS

We found that P. multocida-infected PT-K75 cells show increased gene expression of IL-1β, IL-6, and Muc1 in a dose-dependent manner. Interestingly, these genes resulted in decreased expression in P. multocida pretreated with the P. multocida-specific Pas-MUP-1 bacteriophage. RNA sequencing analysis revealed that bacteriophage administration regulated genes associated with immune and inflammatory responses, and the regulated genes were dramatically concentrated in the cytokine/chemokine-based signaling pathways. Pas-MUP-1 treatment was shown to regulate P. multocida induced gene expression in the bacteria.

CONCLUSION

These results suggest the specific bacteriophage has therapeutic potential as an alternative to antibiotic treatment to defend against P. multocida infection by altering inflammatory gene expression profiles.

Effects of Maternal Supplementation with Rare Earth Elements during Late Gestation and Lactation on Performances, Health, and Fecal Microbiota of the Sows and Their Offspring

Simple Summary

The immunological and metabolic status of breeding sows directly affect the overall productivity of porcine operations. Especially, maternal health status during the transition from gestation to lactation are important in maintaining health and growth of the suckling piglets. Rare earth elements (REEs) have been considered as a promising natural feed additive and been reported to exert their activity locally within the gastrointestinal tract, including effects on the bacterial microflora and on nutrient utilization. The present study was conducted to explore the effects of dietary maternal REE supplementation during late gestation and lactation on sows and their offspring. After the experiment, we found that maternal REE addition enhanced antioxidant activity and immunity of sows and their suckling piglets. At the same time, REE supplementation during perinatal period improved the reproductivity of the sows as well as the growth of their offspring. Besides, maternal REEs supply altered the intestinal microbiota community and composition of sows as well as their offspring, and Spearman correlation analysis shows that fecal bacteria are associated with the antioxidase, inflammatory factors of the sows and offspring as well as average daily gain of the suckling piglets. In addition, our results suggested that REE supplementation during both gestation and lactation are more beneficial to sows and their offspring than supplementation during only late gestation. This paper holds promise in providing efficient feeding strategies in swine production.

Abstract

The study was conducted to investigate the effects of maternal supplementation with rare earth elements (REEs) on sows and their offspring. During late gestation, 120 multiparous sows were divided randomly into the control group (Basal diet) and REE-G group (Basal diet supplemented with 200 mg REE/kg). After delivery, REE-G group was further divided into two groups: REE-L- (Change to basal diet during lactation) and REE-L+ group (REE diet all the time). Our results showed that maternal REE supplementation improved the antioxidant and immunity of sows and piglets. Additionally, REE supply during late gestation significantly decreased the coefficient of within-litter variation (CV) in birth weight and increased the weaning weights and the average daily gain (ADG) of piglets. During lactation, the insulin-like growth factor-1 (IGF-1) levels in piglets of REE-L+ group were higher, while no difference between REE-L- and the control group. More beneficial bacteria (Christensenellaceae and Ruminococcaceae) were found in the REE-L+ group while some opportunistic pathogens (Proteobacteria and Campylobacter) were relatively suppressed. Fecal microbiota showed correlation with antioxidase, inflammatory factors, and average daily gain (ADG). Collectively, our findings indicated that REEs added in both gestation and lactation was more conducive to establish a healthier status for sows and their offspring.

Enterococcus faecium NCIMB 10415 administration improves the intestinal health and immunity in neonatal piglets infected by enterotoxigenic Escherichia coli K88

Background

This study aimed to investigate the effects of oral administration of Enterococcus faecium NCIMB 10415 (E. faecium) on intestinal development, immunological parameters and gut microbiota of neonatal piglets challenged with enterotoxigenic Escherichia coli K88 (ETEC). A total of 96 1-day-old sow-reared piglets were randomly assigned to 2 groups, with 48 piglets in each group. The piglets were from 16 litters (6 piglets each litter), and 3 piglets each litter were allocated to the E. faecium-supplemented (PRO) group, while the other 3 piglets were allocated to the control (CON) group. After colostrum intake, piglets in the PRO group were orally administrated with 3 × 10⁹ CFU E. faecium per day for a period of one week. On day 8, one piglet per litter from each group was challenged (CON+ETEC, PRO+ETEC) or not (CON-ETEC, PRO-ETEC) with ETEC in a 2 × 2 factorial arrangement of treatments. On day 10 (2 days after challenge), blood and tissue samples were obtained from piglets.

Results

Before ETEC challenge, there were no significant differences for the average daily gain (ADG) and fecal score between the two groups of piglets. After ETEC challenge, the challenged piglets had greater fecal score compared to the non-challenged piglets, whereas E. faecium administration was able to decrease the fecal score. Piglets challenged with ETEC had shorter villous height, deeper crypt depth, and reduced number of goblet cells in the jejunum and decreased mRNA abundance of claudin-1 in the ileum, whereas increased the percentage of lymphocytes, concentrations of IL-1β in the plasma and TNF-α in the ileal mucosa, as well as increased the mRNA abundances of innate immunity-related genes in the ileum tissue. These deleterious effects caused by ETEC were partly alleviated by feeding E. faecium. In addition, piglets in PRO-ETEC group had decreased the percentage of CD8⁺ T cells of the peripheral blood when compared to those in CON-ETEC group. Moreover, E. faecium administration increased Verrucomicrobia at phylum level and decreased Bilophila at genus level.

Conclusions

These results suggest that oral administration of E. faecium alleviated the intestinal injury and diarrhea severity of neonatal piglets challenged by ETEC, partly through improving the intestinal microbiota and immune response. This offers a potential strategy of dietary intervention against intestinal impairment by ETEC in neonatal piglets.

Electronic supplementary material

The online version of this article (10.1186/s40104-019-0376-z) contains supplementary material, which is available to authorized users.

The Role of Necroptosis, Apoptosis, and Inflammation in Fowl Cholera-Associated Liver Injury in a Chicken Model

Fowl cholera resulting from infection with Pasteurella multocida causes huge economic losses in the poultry industry. Necrotic hepatitis is reported to be a significant lesion associated with fowl cholera in chickens. Clarifying the underlying molecular mechanism of hepatic injury caused by P. multocida infection is needed to develop new strategies to control fowl cholera. Pasteurella multocida Q (the standard reference strain) and P. multocida 1G1 (a clinical strain) were used to infect healthy laying hens. Clinical signs were observed and gross lesions in livers were observed postmortem. Histologic lesions and the localization and expression of protein molecules associated with necroptosis, apoptosis, and inflammation in hepatic tissues were examined by hematoxylin and eosin staining and immunohistochemistry. Western blot analysis was used to determine the expression of liver injury-related genes. Necroptotic molecules such as RIPK1 (receptor interaction protein kinases 1), RIPK3 (receptor interaction protein kinases 3), and MLKL (mixed lineage kinase domain-like protein) were observed by immunostaining primarily in the cytoplasm of hepatocytes within or around necrotic foci, and inflammatory mediators HMGB1 (high-mobility group box 1) and IL-6 (interleukin-6) were found in the cytoplasm of heterophils, monocytes/macrophages, and hepatic sinusoids. In addition, MMP9 (matrix metalloproteinase 9) and TIMP1 (tissue inhibitor of metalloproteinase 1) were observed in hepatic parenchymal cells, inflammatory cells, and interstitial spaces, whereas the apoptotic effector molecule caspase-3 (cysteine-containing aspartic proteolytic enzymes 3) was mainly found in hepatocytes. The expression of RIPK1, RIPK3, and MLKL was significantly higher in the infected chickens than in the controls. HMGB1 and IL-6 protein levels were also increased in infected chickens relative to those in controls. Both MMP9 and TIMP1 were highly expressed in infected chickens. In addition, caspase-3 protein levels were significantly elevated in infected chickens. Necroptosis, apoptosis, and inflammation played a significant role in hepatic injury caused by P. multocida.

Effects of Intranasal Pseudorabies Virus AH02LA Infection on Microbial Community and Immune Status in the Ileum and Colon of Piglets

Pseudorabies virus (PRV) variants broke out in china since 2011, causing high fever, respiratory distress, systemic neurological symptoms, and diarrhea in piglets. This study investigated the effect of intranasal PRV variant (AH02LA) infection on ileal and colonic bacterial communities and immune status in piglets. Ten piglets (free of PRV) were assigned to PRV variant and control groups (uninfected). At day 5 after inoculation, all piglets were euthanized. No PRV was detected in the ileal and colonic mucosa. In the PRV group, we observed up-regulation of specific cytokines gene expression, down-regulation of intestinal barrier-related gene expression, and reduction of secretory immunoglobulin A (sIgA) concentration in the ileum and colon. PRV infection increased the diversity of ileal bacterial community composition. PRV infection reduced the abundance of some beneficial bacteria (Lactobacillus species in the ileum and colon; butyrate-producing bacteria species in the colon) and increased the abundance of potentially pathogenic Fusobacterium nucleatum in the ileum and Sphingomonas paucimobilis in the colon. Moreover, PRV infection decreased concentrations of the beneficial lactate in the ileum and butyrate in the colon. However, this study does not allow to evaluate whether the observed changes are directly due to the PRV infection or rather to indirect effects (fever, clinical signs and changes in diet), and will be our next research content. In summary, our findings provide evidence that intranasal PRV infection directly or indirectly brings gut health risks and implications, although no PRV was detected in the ileum and colon.

In-vitro phagocytosis and intracellular killing of Pasteurella multocida B:2 by phagocytic cells of buffaloes

Pasteurella multocida B:2 is a Gram-negative organism causing haemorrhagic septicaemia (HS) in buffaloes. It causes severe pulmonary infection, leading to infiltration of numerous macrophages and neutrophils. Despite the inflammatory response, buffaloes succumb to HS. This study aims to evaluate the in-vitro efficacy of macrophages and neutrophils of buffalo following exposure to P. multocida B:2. In-vitro infections were done using 10⁷ cfu/ml of P. multocida B:2 for Group 1, Escherichia coli for Group 2 and Mannhaemia haemolytica A:2 for Group 3 cells. The inoculated cell cultures were harvested at 0, 30, 60 and 120 min post-exposure and the phagocytic, killing and cell death rates were determined. Both phagocytosis and killing rates of all bacteria increased over time. Phagocytosis involved between 71% and 73% neutrophils and between 60% and 64% macrophages at 120 min. Killing rate of all bacteria involved between 76% and 79% for neutrophils and between 70% and 74% for macrophages at 120 min. Death rate of neutrophils ranged between 67% in Group 3, and 88% in Group 1 at 120 min, significantly (p < 0.05) higher than Group 3 but insignificant (p > 0.05) than Group 2. Similar pattern was observed for death rate of macrophages. The phagocytosis and killing rates of P. multocida B:2 were similar to other bacterial species used in this study but more neutrophils and macrophages were dead following infection by P. multocida B:2 than M. haemolytica A:2.

Responses of pro-inflammatory cytokines, acute phase proteins and cytological analysis in serum and cerebrospinal fluid during haemorrhagic septicaemia infection in buffaloes

Sudden death is usually the main finding in field animals during haemorrhagic septicaemia outbreaks caused by Pasteurella multocida type B:2 that causes acute, fatal and septicaemic disease in cattle and buffaloes. This situation may be due to failure in early detection of the disease where early treatment of antibiotics may improve the prognosis of the animal and other surviving animals. Thus, there is a grey area on the knowledge on the potential usage of pro-inflammatory cytokines and acute phase proteins as early biomarkers in the diagnosis of haemorrhagic septicaemia. In addition, exploration of the cerebrospinal fluid during infection has never been studied before. Therefore, this study was designed to fill up the grey areas in haemorrhagic septicaemia research. Twenty-one buffalo calves were divided into seven treatment groups where group 1 was inoculated orally with 10 mL of sterile phosphate-buffered saline pH 7 which act as a negative control group. Groups 2 and 3 were inoculated orally and subcutaneously with 10 mL of 10¹² colony-forming unit of P. multocida type B:2. Group 4 and 5 buffaloes were inoculated orally and intravenously with 10 mL of lipopolysaccharide broth. Groups 6 and 7 were administered orally and subcutaneously with 10 mL of outer membrane protein broth. During the post-infection period of 21 days, blood and cerebrospinal fluid were sampled for the analyses of pro-inflammatory cytokines, acute phase proteins and cytological examination. Buffalo calves infected with P. multocida and its immunogens via different routes of inoculation showed significant changes (p < 0.05) of pro-inflammatory cytokines, acute phase proteins and cytological changes in both the serum and cerebrospinal fluid. Buffalo calves from groups 3 and 7 showed the highest pro-inflammatory cytokines, whereas group 6 had the highest acute phase protein concentration and group 5 revealed the highest value for cytology changes. In summary, results obtained in this study could be used as a profiling study to add novel knowledge to the haemorrhagic septicaemia research as well as the development of biomarkers.

Effects of dietary lysozyme levels on growth performance, intestinal morphology, immunity response and microbiota community of growing pigs

BACKGROUND

Lysozyme has been studied as a potential alternative to antibiotics for animals in recent years. The aim of this study was to evaluate the effect of dietary lysozyme on growth performance, serum biochemical parameters, immune response and gut health of growing pigs.

RESULTS

A total of 216 growing pigs (19.81 ± 0.47 kg) were fed the diets supplemented with colistin sulfate at 20 mg kg^-1 (control), or lysozyme at 50 (L50) or 100 mg kg^-1 (L100) diet for 30 days. The results showed that pigs fed with L100 or control had greater average daily gain and gain-to-feed ratio than pigs in the L50 group. Pigs fed with L100 or colistin had greater villus height to crypt depth ratio in jejunum compared with pigs in the L50 group. Pigs fed with L100 had greater serum immunoglobulin A and jejunal secretory immunoglobulin A than control and L50, but lower serum total protein and globulin than control. No differences were observed in the messenger RNA expression of genes related to mucosal cytokines, antioxidant capacity, enzyme activity, and barrier functions among three treatments. The caecal microflora evenness was lower in the L100 group than in the control or L50 group by 16S ribosomal DNA sequencing. Phylogenetic investigation of communities by reconstruction of unobserved states analysis predicted that lysozyme may modify nutrient metabolism by changing intestinal microbial function of pigs.

CONCLUSIONS

Pigs supplemented with 100 mg kg^-1 lysozyme had similar growth performance and intestinal morphology as pigs fed with colistin. This was likely due to the improved systemic and gut immune responses and the reduced microbiota diversity by feeding 100 mg kg^-1 lysozyme. © 2018 Society of Chemical Industry.

Effects of pyrroloquinoline quinone supplementation on growth performance and small intestine characteristics in weaned pigs

This study was conducted to explore the effect of graded levels of pyrroloquinoline quinone disodium (PQQ·Na2) on the performance and intestinal development of weaned pigs. A total of 216 pigs weaned at 28 d were assigned in a randomized complete block design to 6 diets containing 0, 1.5, 3.0, 4.5, 6.0, or 7.5 mg/kg PQQ·Na2 for 28 d. Performance, diarrhea incidence, intestinal morphology, redox status, cytokines, and the expression of tight junction proteins were determined. Pigs had increased ADG (linear, P < 0.01), G:F (quadratic, P < 0.01), and lower diarrhea incidence (P < 0.01) with the increase of PQQ·Na2 supplementation. Villus height increased (quadratic, P < 0.01) in all segments of the small intestine, and crypt depth in the duodenum and jejunum was decreased (linear, P < 0.05) in pigs with the increase of PQQ·Na2 supplementation. Pigs fed PQQ·Na2-supplemented diets had higher (P < 0.05) activities of antioxidant enzymes including total superoxide dismutase in duodenum, jejunum, and ileum; glutathione peroxidase (GSH-Px) in jejunum and ileum; catalase (CAT) in duodenum and ileum; and lower (P < 0.05) malondialdehyde concentrations in the intestinal mucosa of all segments. In the intestinal mucosa, cytokines including interleukin (IL)-1β, IL-2, and interferon-γ were significantly decreased (P < 0.05) in pigs fed PQQ·Na2-supplemented diets. The protein expression of zonula occluden protein-1 (ZO-1) and occludin in the jejunum was significantly increased (P < 0.05) in pigs fed diets containing PQQ·Na2. In conclusion, these results have indicated that dietary PQQ·Na2 supplementation improves growth performance and gut health in weaned pigs. Moreover, pigs fed diet with as low as 1.5-mg/kg PQQ·Na2 have better performance compared with pigs fed no PQQ·Na2-supplemented diet; pigs fed diet with 4.5-mg/kg PQQ·Na2 have highest G:F among treatments during the whole period.

Effects of dietary supplementation with lysozyme during late gestation and lactation stage on the performance of sows and their offspring

This study investigated the effects of supplementing sow diets with lysozyme during the late gestation to lactation stage on the performance of sows and their offspring. Sixty sows (Yorkshire × Landrace, 3 to 6 of parity) at day 85 of gestation were allocated to the following 3 dietary treatments: 1) sows fed a basal diet from late gestation to lactation (control, n = 20), 2) sows fed a basal diet with lysozyme 150 g/t (LZM 150, n = 20), and 3) sows fed a basal diet with lysozyme 300 g/t (LZM 300, n = 20). During the lactation period, sows fed diets containing lysozyme had increased average daily feed intake (ADFI) (P < 0.01) and decreased weaning-to-estrus interval (WEI, P < 0.05), but there were no significant effects on backfat during the trial among treatments. Sows fed lysozyme diets had increased (P < 0.05) serum concentration of total protein (TP) compared with those fed the control diets. Serum immunoglobulin M (IgM) of the sows increased (P < 0.05) on day 1 of lactation, immunoglobulin A (IgA) and interleukin-10 (IL-10) increased (P < 0.05) on day 7 of lactation, and immunoglobulin G (IgG) had a tendency to increase (P = 0.05) during the lactation. Milk concentration of IgA increased (P < 0.05) on day 1 and 7 of lactation and tended to be greater (P = 0.06) on day 21 of lactation. No significant differences among the dietary treatments were observed in placental tissue mRNA expression of interleukin-6 (IL-6), IL-10, tumor necrosis factor-α (TNF-α), polymeric immunoglobulin receptor (pIgR), or the concentrations of IL-6, IL-10, TNF-α, or secretory immunoglobulin A (sIgA). Moreover, there was a decrease (P < 0.05) in stillborn in sows fed lysozyme diets. The diarrhea rate decreased (P < 0.05) and serum concentrations of IgA, IgG, IgM, and IL-10 increased (P < 0.05) in piglets from sows fed the diets containing lysozyme compared with piglets from sows fed the control diet. The serum concentrations of TP increased (P < 0.05), and albumin (ALB) and globulin (GLB) had a tendency to increase (P = 0.08, P = 0.06) in piglets from sows fed the diets containing lysozyme compared with piglets from sows fed the control diet. In conclusion, this study indicates that feeding sows diets supplemented with lysozyme from the late gestation through lactation stage increased sow ADFI during the lactation, shortened the WEI, and improved the maternal and offspring health status as indicated by immunological characteristics and a reduced incidence of diarrhea in piglets.

Ileum terminal antibiotic infusion affects jejunal and colonic specific microbial population and immune status in growing pigs

Background

Compared with oral antibiotics (primarily disrupt foregut microbiota), the present study used antibiotics with ileum terminal infusion to disrupt the hindgut microbiota, and investigated the changes in specific bacterial composition and immune indexes in the jejunum and colon, and serum of growing pigs. Twelve barrows (45 d of age, 12.08 ± 0.28 kg) fitted with a T-cannula at the terminal ileum, were randomly assigned to two groups and infused either saline without antibiotics (Control) or with antibiotics (Antibiotic) at the terminal ileum. After 25 d experiment, all pigs were euthanized for analyzing bacterial composition and immune status.

Results

Ileum terminal antibiotic infusion (ITAI) altered dominant bacteria counts, with a decrease in Bifidobacterium, Clostridium cluster IV and Clostridium cluster IV in the colon (P < 0.05), and an increase in Escherichia coli in the jejunum (P < 0.05). ITAI decreased (P < 0.05) short-chain fatty acids concentrations in the colon. ITAI decreased interleukin-8 (IL-8), IL-10 and secretory immunoglobulin A (sIgA) concentrations, and down-regulated IL-10, Mucin-1 (MUC1), Mucin-2 (MUC2) and zonula occludens-1 (ZO-1) mRNA expression in the colonic mucosa (P < 0.05). In the jejunal mucosa, ITAI decreased interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), sIgA and IgG levels together with down-regulation of IFN-γ, TNF-α, MUC2 and ZO-1 mRNA expression (P < 0.05). Furthermore, ITAI decreased IL-10, INF-γ, TNF-α, IgA and IgG concentrations in serum (P < 0.05). Correlation analysis revealed that the change in intestinal microbiota was correlated with alterations of Ig and cytokines.

Conclusions

ITAI affected jejunal and colonic specific bacteria counts, and altered some immune markers levels in the jejunal and colonic mucosa and serum. These findings implicate the potential contribution of hindgut bacteria to immune response in the intestinal mucosa and serum of growing pigs.

Electronic supplementary material

The online version of this article (10.1186/s40104-018-0265-x) contains supplementary material, which is available to authorized users.

Anti-Inflammatory, Immunomodulatory, and Antioxidant Activities of Allicin, Norfloxacin, or Their Combination against Pasteurella multocida Infection in Male New Zealand Rabbits

The present study investigated the efficacy of allicin as an antibacterial, anti-inflammatory, antioxidant, and immunostimulant agent in reducing the severity of Pasteurella multocida (P. multocida) type B infection in rabbits. Fifty New Zealand rabbits, 5 weeks old, were divided equally into five groups. Except for group 1, all groups were intranasally infected with P. multocida type B (2 × 10⁵ colony forming units/ml/rabbit). Then, group 3 rabbits were orally treated with allicin (50 mg/kg BW) for 5 days, group 4 rabbits received a single oral dose of norfloxacin 30% (100 mg/kg BW), while group 5 rabbits were treated with a combination of norfloxacin and allicin. Hematological, serum biochemical, inflammatory cytokine, immunological, and histopathological analyses were performed. Results revealed that rabbits, infected with P. multocida type B, exhibited macrocytic hypochromic anemia and leukocytosis with a significant elevation in the phagocytic percentage and index. Moreover, significant reductions in serum total protein, albumin, globulin, and immunoglobulin (IgG and IgM) levels were observed in infected rabbits. Infected rabbits showed significant increases in serum inflammatory cytokine (TNF-α and IL-6), alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase, and serum bilirubin (total, direct, and indirect) levels. Further, P. multocida infection induced oxidative stress as demonstrated by the significant reduction in serum levels of reduced glutathione and superoxide dismutase enzyme and marked elevation in serum malondialdehyde. Treatment with allicin, norfloxacin, or their combination significantly ameliorated the alterations in all studied parameters. In conclusion, allicin could ameliorate the inflammation and oxidative stress, induced by P. multocida type B infection in rabbits.

Dietary supplemented antimicrobial peptide microcin J25 improves the growth performance, apparent total tract digestibility, fecal microbiota, and intestinal barrier function of weaned pigs

Microcin J25 (MccJ25) is an antimicrobial peptide produced by a fecal strain of Escherichia coli containing 21 AA. This study was performed primarily to evaluate the effects of MccJ25 as a potential substitute for antibiotics (AB) on growth performance, nutrient digestibility, fecal microbiota, and intestinal barrier function in weaned pigs. In the present study, 180 weaned pigs (7.98 ± 0.29 kg initial BW) were randomly assigned to 1 of 5 treatments, including a basal diet (CON) and CON supplemented with AB (20 mg/kg colistin sulfate; ABD) or 0.5, 1.0, and 2.0 mg/kg MccJ25. On d 0 to 14, dietary supplementation with MccJ25 and ABD had positive effects on ADG, ADFI, diarrhea incidence, and G:F ( < 0.05). Pigs fed the 2.0 mg/kg MccJ25 diet had greater ADG ( < 0.05) and marginally greater G:F ( < 0.10) compared with pigs fed the ABD diet. Compared with the CON diet, the 2.0 mg/kg MccJ25 diet sharply improved ( < 0.05) ADG and G:F and decreased ( < 0.05) diarrhea incidence (d 15 to 28 and d 0 to 28). Apparent digestibility of nutrients in pigs fed 1.0 and 2.0 mg/kg MccJ25 was improved ( < 0.05) compared with that of pigs fed CON and ABD. The serum cytokines IL-6 and IL-1β and tumor necrosis factor-α levels in pigs fed MccJ25 were greater than in pigs fed CON ( < 0.05). Additionally, the IL-10 concentration in pigs fed MccJ25 was sharply increased ( < 0.05) compared with that of pigs fed CON. Pigs fed 1.0 and 2.0 mg/kg MccJ25 diets had remarkably decreased lactate, diamine oxidase, and endotoxin concentrations and fecal numbers ( < 0.05) and improved fecal and numbers ( < 0.05). Compared with the ABD diet, the diet containing 2.0 mg/kg MccJ25 did not increase lactate, diamine oxidase, and endotoxin (d 14) concentrations ( < 0.05) or decrease the and (d 28) numbers ( < 0.05). The diets containing 1.0 and 2.0 mg/kg MccJ25 and ABD (d 28) improved lactate concentration and short-chain fatty acid concentrations, including acetate, propionate, and butyrate, in feces ( < 0.05). Moreover, the pigs fed 2.0 mg/kg MccJ25 had greater lactate, butyrate (d 14), and propionate concentrations than the pigs fed the ABD diet ( < 0.05). In conclusion, dietary supplemented MccJ25 effectively improved performance, attenuated diarrhea and systematic inflammation, enhanced intestinal barrier function, and improved fecal microbiota composition of weaned pigs. Therefore, MccJ25 could be a potential effective alternative to AB for weaned pigs.

The crucial roles of inflammatory mediators in inflammation: A review

The inflammatory response is a crucial aspect of the tissues' responses to deleterious inflammogens. This complex response involves leukocytes cells such as macrophages, neutrophils, and lymphocytes, also known as inflammatory cells. In response to the inflammatory process, these cells release specialized substances which include vasoactive amines and peptides, eicosanoids, proinflammatory cytokines, and acute-phase proteins, which mediate the inflammatory process by preventing further tissue damage and ultimately resulting in healing and restoration of tissue function. This review discusses the role of the inflammatory cells as well as their by-products in the mediation of inflammatory process. A brief insight into the role of natural anti-inflammatory agents is also discussed. The significance of this study is to explore further and understand the potential mechanism of inflammatory processes to take full advantage of vast and advanced anti-inflammatory therapies. This review aimed to reemphasize the importance on the knowledge of inflammatory processes with the addition of newest and current issues pertaining to this phenomenon.

Effects of Pasteurella multocida lipopolysaccharides on bovine leukocytes

Lipopolysaccharide (LPS) is a major virulence factor of Gram-negative bacteria playing a major role in stimulating protective immune response in mammalian host. However, in many gram-negative bacterial infections, LPS also elicits immunopathology by inducing excessive inflammatory changes. P. multocida (Pm), a gram-negative bacterium, causes acute lung inflammation and fatal septicemic disease in animals. However, the effects of Pm LPS on host cells are little known. In this study, LPS isolated from three different serotypes (B:2, A:1 and A:3) of Pm were individually tested in vitro to assess the response of bovine leukocytes. Pm LPS induced cell proliferation and cell death of leukocytes, in a dose- and time-dependent manner. In these cells, mitochondrial dysfunction and caspase activation mediate cell death.

Chlorogenic Acid Improves Intestinal Development via Suppressing Mucosa Inflammation and Cell Apoptosis in Weaned Pigs

Chlorogenic acid (CGA) is a naturally occurring polyphenol in the human diet and plants, exhibiting antioxidant and anti-inflammatory activities. This study was conducted to investigate the effects of CGA on intestinal development and health in weaned pigs. Twenty-four weaned pigs were randomly assigned to two treatments and fed with a basal diet or a basal diet supplemented with 1000 mg/kg CGA. After a 14 d trial, samples were collected. Compared with the control group, CGA supplementation decreased the serum tumor necrosis factor-α, interleukin-6, and interleukin-1βIL-6 concentrations and elevated the serum immunoglobulin G and jejunal secretory immunoglobulin A concentrations. Meanwhile, jejunal villus height, duodenal and jejunal villus width, and jejunal and ileal villus height/crypt depth were increased by CGA. CGA not only decreased the number of duodenal and jejunal cells in the G0G1 phase but also increased the number of jejunal and ileal cells in the S phase. The percentages of late and total apoptotic cells in jejunum and the ratio of B-cell lymphoma-2-assiciated X protein to B-cell lymphoma-2 (Bcl-2) in duodenum and jejunum were also decreased by CGA supplementation. Finally, CGA upregulated the expression level of Bcl-2 in duodenum and jejunum, whereas it downregulated the expression levels of caspase-3 in duodenum and jejunum, caspase-9 in jejunum, as well as Fas in jejunum and ileum. This study suggested that the beneficial effects of CGA on intestinal development and health are partially due to improvement in immune defense and suppression in excessive apoptosis of intestinal epithelial cells in weaned pigs.

Cytokine gene expression and pathology in experimental Pasteurella multocida infection in mice

The study was conducted to know the pathology and cytokine gene expression studies in experimental infection with Pasteurella multocida in mice. Swiss albino mice (20) were inoculated with P. multocida (200 μl of 1 × 108 cfu/ml) and control mice with sterile PBS intraperitoneally and sacrificed 4 mice at 6, 12, 18 and 24 h. Mice showed dullness, lethargy and unable to move at 18 and 24 h after inoculation. Histopathology revealed changes in liver, kidney, spleen, lung and no observable changes in heart and abdominal muscles. Liver showed septicemia condition and acute bronchopneumonia of lung at 24 h. TNF-α gene showed 20-fold increase in liver and spleen and 5-folds in kidney. There was upregulation of pro-inflammatory cytokines in liver, kidney, spleen and IL–10 gene at later periods of infection which is a new finding, needs further study. Thus, the present study indicated that increase in tissue cytokine gene expression concurred with histopathological changes were attributed to the pathogenesis of Pasteurellosis in mice.

Effect of deoxynivalenol on apoptosis, barrier function, and expression levels of genes involved in nutrient transport, mitochondrial biogenesis and function in IPEC-J2 cells

This study was conducted to determine the effect of 200 ng mL^-1 and 2000 ng mL^-1 deoxynivalenol (DON) on apoptosis, barrier function, nutrient transporter gene expression, and free amino acid variation as well as on mitochondrial biogenesis and function-related gene expression in the intestinal porcine epithelial cell line J2 (IPEC-J2) for 6 h, 12 h, and 24 h. Exposure to 200 ng mL^-1 DON inhibited the cell viability and promoted cell cycle progression from the G2/M phase to the S phase (P < 0.05). The data showed that the IPEC-J2 cell content of free amino acids, such as valine, methionine, leucine, and phenylalanine, was increased (P < 0.05) after treatment for 6 h; the aspartate, threonine, and lysine contents increased (P < 0.05) after treatment for 12 h; and the aspartate, serine, glycine, alanine, isoleucine, leucine, and lysine contents decreased (P < 0.05) after treatment for 24 h. The expression levels of barrier function genes, including zonula occludens 1 (ZO-1), occludin (OCLN), and claudin 1 (CLDN1), showed a significant reduction (P < 0.05). Moreover, the expression levels of differently regulated nutrient transporter genes, including B^0,+ amino acid transporter (B^0,+AT) and sodium-glucose transporter 1 (SGLT1) genes, showed a significant decrease (P < 0.05), while the Na⁺-dependent neutral amino acid transporter 2 (ASCT2) and glucose transporter type 2 (GLUT2) showed a significant increase (P < 0.01). The expression levels of cytokine genes, including IL-8, and IL-1β genes, showed a significant increase (P < 0.05). Furthermore, the expression levels of mitochondrial biogenesis and function-related genes, including mitochondrial transcription factor A (TFAM) and nuclear respiratory factor-1 (NRF), mitochondrial single-strand DNA-binding protein (mt SSB) and mitochondrial polymerase r (mt polr), NADH dehydrogenase subunit 4 (ND4) and cytochrome c oxidase (CcOX) IV, CcOX V and cytochrome c (Cyt c), mammalian silencing information regulator-2α (SIRT-1), glucokinase and citrate synthase (CS), showed a significant increase (P < 0.05). Taken together, the present study indicated that 200 and 2000 ng mL^-1 DON could affect proliferation and cell cycle progression from the G2/M phase to the S phase and could mediate the expression levels of differently regulated barrier function, nutrient transport, and mitochondrial biogenesis and function-related genes.

Genome wide host gene expression analysis in mice experimentally infected with Pasteurella multocida

Pasteurella multocida causes acute septicemic and respiratory diseases, including haemorrhagic septicaemia, in cattle and buffalo with case fatality of 100%. In the present study, mice were infected with P. multocida (1.6 × 10³ cfu, intraperitoneal) to evaluate host gene expression profile at early and late stages of infection using high throughput microarray transcriptome analyses. Several differentially expressed genes (DEGs) at both the time points were identified in P.multocida infected spleen, liver and lungs. Functional annotation of these DEGs showed enrichment of key pathways such as TLR, NF-κB, MAPK, TNF, JAK-STAT and NOD like receptor signaling pathways. Several DEGs overlapped across different KEGG pathways indicating a crosstalk between them. The predicted protein—protein interaction among these DEGs suggested, that the recognition of P. multocida LPS or outer membrane components by TLR4 and CD14, results in intracellular signaling via MyD88, IRAKs and/or TRAF6 leading to activation of NFκB and MAPK pathways and associated cytokines.

Transcriptomic Analysis on Responses of Murine Lungs to Pasteurella multocida Infection

Pasteurella multocida infection in cattle causes serious epidemic diseases and leads to great economic losses in livestock industry; however, little is known about the interaction between host and P. multocida in the lungs. To explore a fully insight into the host responses in the lungs during P. multocida infection, a mouse model of Pasteurella pneumonia was established by intraperitoneal infection, and then transcriptomic analysis of infected lungs was performed. P. multocida localized and grew in murine lungs, and induced inflammation in the lungs, as well as mice death. With transcriptomic analysis, approximately 10⁷ clean reads were acquired. 4236 differently expressed genes (DEGs) were detected during P. multocida infection, of which 1924 DEGs were up-regulated. By gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichments, 5,303 GO enrichments and 116 KEGG pathways were significantly enriched in the context of P. multocida infection. Interestingly, genes related to immune responses, such as pattern recognition receptors (PRRs), chemokines and inflammatory cytokines, were significantly up-regulated, suggesting the key roles of these genes in P. multocida infection. Transcriptomic data showed that IFN-γ/IL-17-related genes were increased, which were validated by qRT-PCR, ELISA, and immunoblotting. Our study characterized the transcriptomic profile of the lungs in mice upon Pasteurella infection, and our findings could provide valuable information with respect to better understanding the responses in mice during P. multocida infection.