In vivo and in vitro protective effect of arginine against intestinal inflammatory response induced by Clostridium perfringens in broiler chickens

Effect of 125% and 135% arginine on the growth performance, intestinal health, and immune responses of broilers during necrotic enteritis challenge

The objective of this study was to evaluate the effects of 25% and 35% arginine supplementation in partially alleviating the effects of necrotic enteritis (NE) challenge on the production performance, intestinal integrity, and relative gene expression of tight junction proteins and inflammatory cytokines in broilers. Four hundred and eighty 1-day-old chicks were randomly allocated to the 4 treatments- Uninfected + Basal, NE + Basal, NE + Arg 125%, and NE + Arg 135%. NE was induced by inoculating 1 × 104Eimeria maxima sporulated oocysts on d 14 and 1 × 108 CFU/bird C. perfringens on d 19, 20, and 21 of age by oral gavage. The NE challenge significantly decreased body weight gain (BWG) (p < 0.05) and increased the feed conversion ratio (FCR) (p < 0.05). On d 21, the NE challenge also increased the jejunal lesion score (p < 0.05) and relative gene expression of IL-10 and decreased the expression of the tight junction proteins occludin (p < 0.05) and claudin-4 (p < 0.05). The 125% arginine diet significantly increased intestinal permeability (p < 0.05) and the relative gene expression of iNOS (p < 0.05) and IFN-γ (p < 0.05) on d 21 and the bile anti-C. perfringens IgA concentration by 39.74% (p < 0.05) on d 28. The 135% arginine diet significantly increased the feed intake during d 0 - 28 (p < 0.05) and 0 to 35 (p < 0.05) and increased the FCR on d 0 to 35 (p < 0.05). The 135% and 125% arginine diet increased the spleen CD8+: CD4+ T-cell ratio on d 28 (p < 0.05) and 35 (p < 0.05), respectively. The 135% arginine diet increased the CT CD8+:CD4+ T-cell ratio on d 35 (p < 0.05). In conclusion, the 125% and 135% arginine diets did not reverse the effect of the NE challenge on the growth performance. However, the 125% arginine diet significantly increased the cellular and humoral immune response to the challenge. Hence, the 125% arginine diet could be used with other feed additives to improve the immune response of the broilers during the NE challenge.

Effect of arginine supplementation on the growth performance, intestinal health, and immune responses of broilers during necrotic enteritis challenge

The objective of this study was to evaluate the effect of 25% arginine supplementation as a functional amino acid in partially alleviating the detrimental effects of necrotic enteritis (NE) on the growth performance, serum biochemistry, gut integrity, and the relative gene expression of tight junction proteins and inflammatory cytokines in broilers during NE. Three hundred and sixty 1-day-old chicks were randomly allocated to 4 treatments in a 2 × 2 factorial arrangement -basal diet and 125% arginine diet, with or without NE challenge. NE was induced by inoculating 1 × 104Eimeria maxima sporulated oocysts on d 14 and 1 × 108 CFU/bird C. perfringens on d 19, 20, and 21. The NE challenge had a significant effect on the BWG (p < 0.05), FCR (p < 0.05), serum AST (p < 0.05), GLU (p < 0.05), and K+ (p < 0.05) levels, and intestinal permeability (p < 0.05) and jejunal lesion score (p < 0.05). A significant challenge × diet interaction effect was observed in the cecal tonsil CD8+: CD4+ T-cell ratio on d 21 (p < 0.05) and 28 (p < 0.05) and spleen CD8+: CD4+ T-cell ratio on d 21 (p < 0.05) and 35 (p < 0.05). Arginine supplementation significantly increased the CD8+: CD4+ T-cell ratio in uninfected birds but decreased the CD8+: CD4+ T-cell ratio in infected birds. On d 21, a significant interaction effect was observed on the relative expression of the iNOS gene (p < 0.05). Arginine supplementation significantly downregulated the expression of the iNOS gene in infected birds. A significant effect of the challenge (p < 0.05) was observed on the relative gene expression of the ZO-1 gene in the jejunum. NE challenge significantly downregulated the expression of the ZO-1 gene on d 21. In conclusion, arginine supplementation did not alleviate the depression in growth performance and disease severity during the NE challenge. However, arginine downregulated the expression of inflammatory cytokines and enzymes, preventing inflammatory injury to the tissues during NE. Hence, arginine might be supplemented with other alternatives to downregulate inflammatory response during NE in poultry.

Mechanisms of intestinal epithelial cell damage by Clostridiumperfringens

Clostridium perfringens, a Gram-positive bacterium, causes intestinal diseases in humans and livestock through its toxins, related to alpha toxin (CPA), beta toxin (CPB), C. perfringens enterotoxin (CPE), epsilon toxin (ETX), Iota toxin (ITX), and necrotic enteritis B-like toxin (NetB). These toxins disrupt intestinal barrier, leading to various cell death mechanisms such as necrosis, apoptosis, and necroptosis. Additionally, non-toxin factors like adhesins and degradative enzymes contribute to virulence by enhancing colonization and survival of C. perfringens. A vicious cycle of intestinal barrier breach, misregulated cell death, and subsequent inflammation is at the heart of chronic inflammatory and infectious gastrointestinal diseases. Understanding these mechanisms is essential for developing targeted therapies against C. perfringens-associated intestinal diseases.

Exploring the therapeutic potential of regulatory T cell in rheumatoid arthritis: Insights into subsets, markers, and signaling pathways

Rheumatoid arthritis (RA) is a complex autoimmune inflammatory rheumatic disease characterized by an imbalance between immunological reactivity and immune tolerance. Regulatory T cells (Tregs), which play a crucial role in controlling ongoing autoimmunity and maintaining peripheral tolerance, have shown great potential for the treatment of autoimmune inflammatory rheumatic diseases such as RA. This review aims to provide an updated summary of the latest insights into Treg-targeting techniques in RA. We focus on current therapeutic strategies for targeting Tregs based on discussing their subsets, surface markers, suppressive function, and signaling pathways in RA.

Arginine alleviates Clostridium perfringens α toxin-induced intestinal injury in vivo and in vitro via the SLC38A9/mTORC1 pathway

Introduction

Clostridium perfringens α toxin is a main virulence factor responsible for gut damage in animals. Arginine is a functional amino acid exhibiting significant immunoregulatory activities. However, the effects and immunoregulatory mechanisms of arginine supplementation on α toxin-induced intestinal injury remain unclear.

Methods

In vivo, 256 male Arbor Acres chickens were randomly assigned to a 2×2 factorial arrangement, involving diet treatments (with or without 0.3% arginine supplementation) and immunological stress (with or without α toxin challenge). In vitro, IEC-6 cells were treated with or without arginine in the presence or absence of α toxin. Moreover, IEC-6 cells were transfected with siRNA targeting mTOR and SLC38A9 to explore the underlying mechanisms.

Results and discussion

The results showed that in vivo, arginine supplementation significantly alleviated the α toxin-induced growth performance impairment, decreases in serum immunoglobulin (Ig)A and IgG levels, and intestinal morphology damage. Arginine supplementation also significantly reduced the α toxin-induced increase in jejunal proinflammatory cytokines interleukin (IL)-1β, IL-6 and IL-17 mRNA expression. Clostridium perfringens α toxin significantly decreased jejunal mechanistic target of rapamycin (mTOR) and solute carrier family 38 member 9 (SLC38A9) mRNA expression, while arginine supplementation significantly increased mTOR and SLC38A9 mRNA expression. In vitro, arginine pretreatment mitigated the α toxin-induced decrease in cell viability and the increase in cytotoxicity and apoptosis. Arginine pretreatment also alleviated the α toxin-induced upregulation of mRNA expression of inflammation-related cytokines IL-6, C-X-C motif chemokine ligand (CXCL)10, CXCL11 and transforming growth factor-β (TGF-β), as well as apoptosis-related genes B-cell lymphoma-2 associated X protein (Bax), B-cell lymphoma-2 (Bcl-2), B-cell lymphoma-extra large (Bcl-XL) and cysteinyl aspartate specific proteinase 3 (Caspase-3) and the ratio of Bax to Bcl-2. Arginine pretreatment significantly increased the α toxin-induced decrease in mTOR, SLC38A9, eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4EBP1) and ribosomal protein S6 kinase (S6K) mRNA expression. Knockdown SLC38A9 and mTOR largely abrogated the positive effects of arginine pretreatment on α toxin-induced intracellular changes. Furthermore, SLC38A9 silencing abolished the increased mTOR mRNA expression caused by arginine pretreatment. In conclusion, arginine administration attenuated α toxin-induced intestinal injury in vivo and in vitro, which could be associated with the downregulation of inflammation via regulating SLC38A9/mTORC1 pathway.

Probiotic cocktails accelerate baicalin metabolism in the ileum to modulate intestinal health in broiler chickens

BACKGROUND

Baicalin and probiotic cocktails are promising feed additives with broad application prospects. While probiotic cocktails are known to enhance intestinal health, the potential synergistic impact of combining baicalin with probiotic cocktails on the gut health of broiler chickens remains largely unexplored. Therefore, this study aims to investigate the influence of the combined administration of baicalin and probiotic cocktails on the composition of ileal and cecal microbiota in broiler chickens to elucidate the underlying mechanisms responsible for the health-promoting effects.

RESULTS

A total of 320 1-day-old male Arbor Acres broilers were divided into 4 groups, each with 8 replicates of 10 chicks per replicate. Over a period of 42 d, the birds were fed a basal diet or the same diet supplemented with 37.5 g/t baicalin (BC), 1,000 g/t probiotic cocktails (PC), or a combination of both BC (37.5 g/t) and PC (1,000 g/t). The results demonstrated that BC + PC exhibited positive synergistic effects, enhancing intestinal morphology, immune function, and barrier function. This was evidenced by increased VH/CD ratio, sIgA levels, and upregulated expression of occludin and claudin-1 (P < 0.05). 16S rRNA analysis indicated that PC potentiated the effects of BC, particularly in the ileum, where BC + PC significantly increased the α-diversity of the ileal microbiota, altered its β-diversity, and increased the relative abundance of Flavonifractor (P < 0.05), a flavonoid-metabolizing bacterium. Furthermore, Flavonifractor positively correlated with chicken ileum crypt depth (P < 0.05). While BC + PC had a limited effect on cecal microbiota structure, the PC group had a very similar microbial composition to BC + PC, suggesting that the effect of PC at the distal end of the gut overshadowed those of BC.

CONCLUSIONS

We demonstrated the synergistic enhancement of gut health regulation in broiler chickens by combining baicalin and probiotic cocktails. Probiotic cocktails enhanced the effects of baicalin and accelerated its metabolism in the ileum, thereby influencing the ileal microbiota structure. This study elucidates the interaction mechanism between probiotic cocktails and plant extract additives within the host microbiota. These findings provide compelling evidence for the future development of feed additive combinations.

Beyond protein synthesis: the emerging role of arginine in poultry nutrition and host-microbe interactions

Arginine is a functional amino acid essential for various physiological processes in poultry. The dietary essentiality of arginine in poultry stems from the absence of the enzyme carbamoyl phosphate synthase-I. The specific requirement for arginine in poultry varies based on several factors, such as age, dietary factors, and physiological status. Additionally, arginine absorption and utilization are also influenced by the presence of antagonists. However, dietary interventions can mitigate the effect of these factors affecting arginine utilization. In poultry, arginine is utilized by four enzymes, namely, inducible nitric oxide synthase arginase, arginine decarboxylase and arginine: glycine amidinotransferase (AGAT). The intermediates and products of arginine metabolism by these enzymes mediate the different physiological functions of arginine in poultry. The most studied function of arginine in humans, as well as poultry, is its role in immune response. Arginine exerts immunomodulatory functions primarily through the metabolites nitric oxide (NO), ornithine, citrulline, and polyamines, which take part in inflammation or the resolution of inflammation. These properties of arginine and arginine metabolites potentiate its use as a nutraceutical to prevent the incidence of enteric diseases in poultry. Furthermore, arginine is utilized by the poultry gut microbiota, the metabolites of which might have important implications for gut microbial composition, immune regulation, metabolism, and overall host health. This comprehensive review provides insights into the multifaceted roles of arginine and arginine metabolites in poultry nutrition and wellbeing, with particular emphasis on the potential of arginine in immune regulation and microbial homeostasis in poultry.

Effects of Dietary Limosilactobacillus fermentum and Lacticaseibacillus paracasei Supplementation on the Intestinal Stem Cell Proliferation, Immunity, and Ileal Microbiota of Broiler Chickens Challenged by Coccidia and Clostridium perfringens

This study was conducted to investigate effects of dietary Limosilactobacillus fermentum and Lacticaseibacillus paracasei supplementation on the intestinal stem cell proliferation, immunity, and ileal microbiota of broiler chickens challenged by coccidia and Clostridium perfringens. A total of 336 one-day-old Ross 308 chickens were randomly assigned into four groups. Chickens in the control (CTR) group were fed basal diet, and chickens in the three challenged groups were fed basal diets supplemented with nothing (CCP group), 1.0 × 109 CFU/kg L. fermentum (LF_CCP group), and 1.0 × 109 CFU/kg L. paracasei (LP_CCP group), respectively. All challenged birds were infected with coccildia on day 9 and Clostridium perfringens during days 13-18. The serum and intestinal samples were collected on days 13 and 19. The results showed that L. fermentum significantly increased jejunal gene expression of cdxB (one of the intestinal stem cell marker genes) on day 13. Additionally, L. fermentum significantly up-regulated mRNA levels of JAK3 and TYK2 and tended to increase STAT6 mRNA expression in jejunum on day 19. In the cecal tonsil, both L. fermentum and L. paracasei decreased mRNA expression of JAK2 on day 13, and L. fermentum down-regulated JAK1-2, STAT1, and STAT5-6 gene expressions on day 19. Ileal microbiological analysis showed that coccidial infection increased the Escherichia-Shigella, Lactobacillus, and Romboutsia abundance and decreased Candidatus_Arthromitus richness on day 13, which were reversed by Lactobacillus intervention. Moreover, Lactobacilli increased ileal Lactobacillus richness on day 19. In conclusion, Lactobacilli alleviated the impairment of intestinal stem cell proliferation and immunity in coccidia- and C. perfringens-challenged birds via modulating JAK/STAT signaling and reshaping intestinal microflora.

Dietary methionine sources and levels modulate the intestinal health status of broiler chickens

Given the key role of methionine in biological processes, adequate methionine should be provided to meet the nutritional requirements. DL-2-hydroxy-4-(methylthio)-butanoic acid (DL-HMTBA) has been considered as an important source of methionine. However, the effects of different sources and levels of methionine on the intestinal health status have not been clarified yet. An experiment was carried out to investigate the effects of different dietary sources and levels of methionine on the intestinal epithelial barrier, inflammatory cytokines expression, ileal morphology, microbiota composition, and cecal short chain fatty acids (SCFA) profiles. For this purpose, 720 male Arbor Acre broiler chicks at 1 d old were randomly assigned to a 2 × 3 factorial arrangement with 2 methionine sources (DL-methionine and DL-HMTBA) and 3 total sulfur amino acids (TSAA) levels (80%, 100%, and 120% of Arbor Acre recommendation). The results showed that DL-HMTBA supplementation promoted intestinal physical barrier at both gene expression level of claudin-1 and serum diamine oxidase level (P < 0.05), and the inflammatory cytokine IL-6 mRNA expression was down-regulated by dietary DL-HMTBA supplementation compared with the DL-methionine group (P < 0.05). Meanwhile, an upregulated gene expression of claudin-1 and zonula occluden-1 (ZO-1) were observed in the low-TSAA treatment on d 14 (P < 0.05), whereas this treatment increased the expression of IL-1β and IL-6 (P < 0.05). Villus height to crypt depth ratio was high (P < 0.05) in the middle-level TSAA group. Furthermore, DL-HMTBA supplementation optimized the microbiota of the ileum especially the relative abundance of Lactobacillus, where the digestion and absorption were completed, and elevated the concentrations of SCFA (acetate, propionate, and butyrate) in the cecal content on d 21 (P < 0.01). In conclusion, dietary DL-HMTBA supplementation improved the intestinal barrier function, immune homeostasis and optimized the microbiota to promote intestinal health status in broiler chickens.

The protective effects of Bacillus licheniformis against inflammatory responses and intestinal barrier damage in broilers with necrotic enteritis induced by Clostridium perfringens

BACKGROUND

Bacillus licheniformis is a gram-positive bacterium that has strong environmental adaptability and can improve the growth performance, immunity, and antioxidant function of broilers. The current study aimed to elucidate the protective capability of B. licheniformis against inflammatory responses and intestinal barrier damage in broilers with necrotic enteritis (NE) induced by Clostridium perfringens (CP).

RESULTS

The results showed that B. licheniformis enhanced the final body weight in broilers compared with that of broilers in the CP group after the stress of infection (P < 0.05). Bacillus licheniformis reversed the decreased levels of serum and jejunum mucosa immunoglobulins and anti-inflammatory cytokines, reduced the values of villus height and the ratio of villus height to crypt depth, and mitigated the increased levels of serum d-lactic acid and diamine oxidase in CP-challenged broilers (P < 0.05). Moreover, B. licheniformis modulated the expression levels of genes involved in the TLR4/NF-κB signalling pathway, the NLRP3 inflammasome activation pathway, and the sirt 1/Parkin signalling pathway in CP-challenged broilers. Compared with the CP challenge group, the B. licheniformis-treated group exhibited reduced abundance values of Shuttleworthia and Alistipes and enhanced abundance values of Parabacteroides in the caecal contents (P < 0.05).

CONCLUSION

Bacillus licheniformis improved the final body weight and alleviated the inflammatory response and intestinal barrier function damage in birds with NE induced by CP by maintaining intestinal physiological function, enhancing immunity, regulating inflammatory cytokine secretion, modulating the mitophagy response, and increasing the abundance of beneficial intestinal flora. © 2023 Society of Chemical Industry.

Molecular characterization and function of JAK/STAT pathway in IPEC-J2 cells during Clostridium perfringens beta2 toxin stimulation

Intestinal infection with C. perfringens is responsible for outbreaks of diarrhea in piglets. Janus kinase / signal transducer and activator of transcription (JAK/STAT) is a vital signaling pathway that regulates cellular activity and inflammatory response, closely correlated with multiple diseases development and advances. Currently, the potential effect of JAK/STAT on C. perfringens beta2 (CPB2) treatment on porcine intestinal epithelial (IPEC-J2) cells has not been explored. The expression of JAK/STAT genes or proteins in IPEC-J2 cells induced by CPB2 were observed by qRT-PCR and Western blot, and further used WP1066 to explore the effect of JAK2/STAT3 on mechanism employed by CPB2 on apoptosis, cytotoxicity, oxidative stress and inflammatory cytokines of IPEC-J2 cells. JAK2, JAK3, STAT1, STAT3, STAT5A and STAT6 were highly expressed in CPB2-induced IPEC-J2 cells, among which STAT3 had the highest expression. Moreover, apoptosis, cytotoxicity and oxidative stress were attenuated via blocking the activation of JAK2/STAT3 by using WP1066 in CPB2-treated IPEC-J2 cells. Furthermore, WP1066 significantly suppressed the secretion of interleukin (IL)-6, IL-1β and TNF-α induced by CPB2 in IPEC-J2 cells.Our findings provide some insights into the functional roles of JAK2/STAT3 in piglets against to C. perfringens infection.

Effects of Vitamin A on Immune Responses and Vitamin A Metabolism in Broiler Chickens Challenged with Necrotic Enteritis

Necrotic enteritis (NE) is an important enteric inflammatory disease of poultry, and the effects of vitamin A (VitA) on NE birds are largely unknown. The present study was conducted to investigate the effects of VitA on the immune responses and VitA metabolism of NE broilers as well as the underlying mechanisms. Using a 2 × 2 factorial arrangement, 336 1-day-old Ross 308 broiler chicks were randomly assigned to 4 groups with 7 replicates. Broilers in the control (Ctrl) group were fed a basal diet without extra VitA supplementation. Broilers in the VitA group were fed a basal diet supplemented with 12,000 IU/kg of VitA. Birds in NE and VitA + NE groups were fed corresponding diets and, in addition, co-infected with Eimeria spp. and Clostridium perfringens on days 14 to 20. Samples of the blood, jejunum, spleen and liver were obtained on day 28 for analysis, and meanwhile, lesion scores were also recorded. The results showed that NE challenge increased lesion score in the jejunum and decreased serum glucose, total glyceride, calcium, phosphorus and uric acid levels (p < 0.05). VitA supplementation reduced the levels of serum phosphorus, uric acid and alkaline phosphatase in NE-challenged birds and increased serum low-density lipoprotein content and the activity of aspartate aminotransferase and creatine kinase (p < 0.05). Compared with the Ctrl group, the VitA and NE groups had higher mRNA expression of interferon-γ in the jejunum (p < 0.05). NE challenge up-regulated mRNA expression of interleukin (IL)-13, transforming growth factor-β4, aldehyde dehydrogenase (RALDH)-2 and RALDH-3 in the jejunum, while VitA supplementation increased jejunal IL-13 mRNA expression and hepatic VitA content, but down-regulated splenic IL-13 mRNA expression (p < 0.05). The VitA + NE group had higher serum prostaglandin E₂ levels and the Ctrl group had higher splenic RALDH-3 mRNA expression than that of the other three groups (p < 0.05). NE challenge up-regulated jejunal retinoic acid receptor (RAR)-β and retinoid X receptor (RXR)-α as well as splenic RAR-α and RAR-β mRNA expression (p < 0.05). VitA supplementation up-regulated jejunal RAR-β expression but down-regulated mRNA expression of RXR-α, RXR-γ, signal transducers and activators of transcription (STAT) 5 and STAT6 in the spleen (p < 0.05). Moreover, compared with the Ctrl group, the VitA and NE groups had down-regulated mRNA expression of jejunal and splenic Janus kinase (JAK) 1 (p < 0.05). In conclusion, NE challenge induced jejunal injury and expression of Th2 and Treg cell-related cytokines and enhanced RALDH and RAR/RXR mRNA expression, mainly in the jejunum of broilers. VitA supplementation did not alleviate jejunal injury or Th2 cell-related cytokine expression; however, it improved hepatic VitA deposition and inhibited the expression of RALDH-3, RXR and the JAK/STAT signaling pathway in the spleen of broilers. In short, the present study suggested the modulatory effects of vitamin A on the immune responses and vitamin A metabolism in broiler chickens challenged with necrotic enteritis.

Barley Leaf Ameliorates Citrobacter-rodentium-Induced Colitis through Arginine Enrichment

Inflammatory bowel disease (IBD) has become a global public health challenge. Our previous study showed that barley leaf (BL) significantly reduces Citrobacter-rodentium (CR)-induced colitis, but its mechanism remains elusive. Thus, in this study, we used non-targeted metabolomics techniques to search for potentially effective metabolites. Our results demonstrated that dietary supplementation with BL significantly enriched arginine and that arginine intervention significantly ameliorated CR-induced colitis symptoms such as reduced body weight, shortened colon, wrinkled cecum, and swollen colon wall in mice; in addition, arginine intervention dramatically ameliorated CR-induced histopathological damage to the colon. The gut microbial diversity analysis showed that arginine intervention significantly decreased the relative abundance of CR and significantly increased the relative abundance of Akkermansia, Blautia, Enterorhabdus, and Lachnospiraceae, which modified the CR-induced intestinal flora disorder. Notably, arginine showed a dose-dependent effect on the improvement of colitis caused by CR.

Citric Acid and Magnolol Ameliorate Clostridium perfringens Challenge in Broiler Chickens

Clostridium perfringens (C. perfringens) is a common pathogenic bacterium implicated in the enteric diseases of animals. Each year, the disease is responsible for billions of dollars of losses worldwide. The development of new phytomedicines as alternatives to antibiotics is becoming a new hotspot for treating such diseases. Citric acid (CA) and magnolol (MA) have been shown to have antibacterial, antioxidant, and growth-promoting properties. Here, the bacteriostatic effects of combinations of CA and MA against C. perfringens were investigated, together with their effects on yellow-hair chickens challenged with C. perfringens. It was found that the optimal CA:MA ratio was 50:3, with a dose of 265 μg/mL significantly inhibiting C. perfringens growth, and 530 μg/mL causing significant damage to the bacterial cell morphology. In animal experiments, C. perfringens challenge reduced the growth, damaged the intestinal structure, activated inflammatory signaling, impaired antioxidant capacity, and perturbed the intestinal flora. These effects were alleviated by combined CA-MA treatment. The CA-MA combination was found to inhibit the TLR/Myd88/NF-κB and Nrf-2/HO-1 signaling pathways. In conclusion, the results suggest the potential of combined CA-MA treatment in alleviating C. perfringens challenge by inhibiting the growth of C. perfringens and affecting the TLR/MyD88/NF-κB and Nrf-2/HO-1 signaling pathways.

Gut transcriptome reveals differential gene expression and enriched pathways linked to immune activation in response to weaning in pigs

Weaning represents one of the most critical periods in pig production associated with increase in disease risk, reduction in performance and economic loss. Physiological changes faced by piglets during the weaning period have been well characterised, however little is currently known about the underlying molecular pathways involved in these processes. As pig meat remains one of the most consumed sources of protein worldwide, understanding how these changes are mediated is critical to improve pig production and consequently sustainable food production globally. In this study, we evaluated the effect of weaning on transcriptomic changes in the colon of healthy piglets over time using an RNA-sequencing approach. The findings revealed a complex and coordinated response to weaning with the majority of genes found to be rapidly differentially expressed within 1 day post weaning. Multiple genes and pathways affected by weaning in the colon were associated with immune regulation, cell signalling and bacterial defence. NOD-like receptors, Toll-like receptor and JAK-STAT signalling pathways were amongst the pathways significantly enriched. Immune activation was evidenced by the enrichment of pathways involved in interferon response, cytokines interactions, oxidoreductase activities and response to microbial invasion. Biosynthesis of amino acids, in particular arginine, was also amongst the most enriched KEGG pathways in weaned pigs, reinforcing the critical role of arginine in gut homeostasis under stress conditions. Overall, transcriptomic and physiological results suggest that pigs going through the weaning transition undergo a transient period of inflammatory state with a temporary breakdown of barrier functions in the gut. These findings could provide valuable tools to monitor host response post weaning, and may be of particular relevance for the investigation and development of intervention strategies aimed to reduce antibiotic use and improve pig health and performance.

Artificial gut and the applications in poultry: A review

Artificial gut models including both the gastric and intestinal phases have been used in poultry research for decades to predict the digestibility of nutrients, the efficacy of feed enzymes and additives, and caecal fermentation. However, the models used in the past are static and cannot be used to predict interactions between the feed, gut environment and microbiome. It is imperative that a standard artificial gut model for poultry is established, to enable these interactions to be examined without continual reliance on animals. To ensure the validity of an artificial model, it should be validated with in vivo studies. This review describes current practices in the use of artificial guts in research, their importance in poultry nutrition studies and highlights an opportunity to develop a dynamic gut model for poultry to reduce the number of in vivo experiments.

Therapeutic effect of heat-killed Lactobacillus plantarum L-137 on the gut health and growth of broilers

Although some studies on the effects of para-probiotics on the immune system and intestinal health have been conducted independently of research on antibiotics ass growth promoters. This study investigated the effects of heat-killed Lactobacillus plantarumL-137 (L-137) and antibiotics as preventive and/or therapeutic substances for broilers against subclinical necrotic enteritis caused by Clostridium perfringens (CP). In total, 300 1-day-old broilers (46.13 ± 1.38 g) were randomly stocked at 10 birds pen^-1 in five replicates and divided into six groups, namely T1 and T2, positive and negative control of CP challenge; T3 and T4, prevention with basal diet plus 10 and 50 mg/kg L-137; T5 and T6, prevention and treatment with basal diet plus 50 mg/kg of L-137 and bacitracin at 50 ppm, respectively. Broilers administered L-137 in T4, T5 and bacitracin in T6 showed an improved (p < 0.05) villus height/crypt depth ratio than control groups, suggesting that it might significantly boost growth performance. In contrast to bacitracin, a high dosage of L-137 significantly increased (p < 0.05) the spleen index value and the cytokine levels, as well as the expression of intestinal β-defensin genes on day 28. During the 42-day production period, broilers in T4 and T5 showed a significantly enhanced (p < 0.05) expression of cytokines, AvBD-1 and AvBD-7 on day 42 compared to the control and bacitracin groups. In particular, broilers given the L-137 diets demonstrated no cumulative mortality following CP exposure, compared to a 2% mortality in T6. Our findings provide insight into eco-friendly alternatives to antibiotics for maximizing growth performance, feed efficiency and long-term disease protection in chickens; however, this has to be proven in larger-scale commercial experiments.

Dietary ellagic acid ameliorated Clostridium perfringens-induced subclinical necrotic enteritis in broilers via regulating inflammation and cecal microbiota

Background

Subclinical necrotic enteritis (SNE), a common intestinal disease of broiler caused by Clostridium perfringens, could reduce production performance of broilers by chronic intestinal damage and poor absorption of nutrients. Ellagic acid (EA) has been reported to present antioxidant and anti-inflammatory properties on human and animals in many aspects. This study was conducted to evaluate the effect and mechanism of EA in relieving SNE in broilers induced by C. perfringens.

Results

C. perfringens challenge decreased body weight (BW), average daily gain (ADG), jejunal villi height/crypt depth (V/C) ratio, the activity of catalase (CAT) and the mRNA expression of zonula occludens 1 (ZO-1) in jejunal mucosa of broilers. While feed conversion ratios (FCR), jejunal crypt depth (CD), the activities of myeloperoxidase (MPO) and diamine oxidase (DAO), as well as the concentrations of interleukin 6 (IL-6), C-reactive protein (CRP) and procalcitonin (PCT) in serum, the activities of inducible nitric oxide synthase (iNOS) and lysozyme (LZM), the concentration of malondialdehyde (MDA), and the mRNA expressions of claudin-2, TNF-α, IL-1β, TLR-4, TLR-2, NF-κB, JAK3, STAT6 and iNOS in jejunal mucosa of broilers were increased by C. perfringens challenge. Dietary EA supplement relieved these adverse effects, and heightened jejunal villi height (VH), the concentration of D-xylose in plasma, activity of superoxide dismutase (SOD), and the mRNA expression of occludin in jejunal mucosa of broilers. The alpha diversity of cecal microbiota indicated that dietary EA supplement increased observed species and Shannon index. C. perfringens challenge increased the relative abundance of Firmicutes and decreased the relative abundance of Desulfobacterota in cecal microbiota. EA increased the relative abundance of Firmicutes in cecal microbiota. LEfSe analysis showed that C. perfringens challenge triggered the imbalance of cecal microbiota in broilers, dietary EA supplementation led to a small beneficial effect on microbiota, while the simultaneous effect of them seemed to stimulate the immune function of broilers by improving the microbiota balance.

Conclusions

Dietary EA ameliorated C. perfringens-induced SNE in broilers via regulating jejunal inflammation signaling pathways TLR/NF-κB and JAK3/STAT6, relieving jejunal oxidative stress and balancing cecal microbiota to inhibit intestinal barrier damage, prevent systemic inflammatory response and improve nutrient absorption capacity, finally protect and enhance growth performance of broilers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-022-00694-3.

A blend of microencapsulated organic acids and botanicals reduces necrotic enteritis via specific signaling pathways in broilers

Necrotic enteritis (NE) is a devastating disease that has seen a resurgence of cases following the removal of antibiotics from feed resulting in financial loss and significant animal health concerns across the poultry industry. The objective was to evaluate the efficacy of a microencapsulated blend of organic (25% citric and 16.7% sorbic) acids and botanicals (1.7% thymol and 1% vanillin [AviPlusP]) to reduce clinical NE and determine the signaling pathways associated with any changes. Day-of-hatch by-product broiler breeder chicks were randomly assigned to a control (0) or supplemented (500 g/MT) diet (n = 23-26) and evaluated in a NE challenge model (n = 3). Birds were administered 2X cocci vaccine on d 14 and challenged with a cocktail of Clostridium perfringens strains (107) on d 17 to 19. On d 20 to 21 birds were weighed, euthanized, and scored for NE lesions. Jejunal tissue was collected for kinome analysis using an immuno-metabolism peptide array (n = 5; 15/treatment) to compare tissue from supplement-fed birds to controls. Mortality and weight were analyzed using Student's t test and lesion scores analyzed using F-test two-sample for variances (P < 0.05). The kinome data was analyzed using PIIKA2 peptide array analysis software and fold-change between control and treated groups determined. Mortality in the supplemented group was 47.4% and 70.7% in controls (P = 0.004). Lesions scores were lower (P = 0.006) in supplemented birds (2.47) compared to controls (3.3). Supplement-fed birds tended (P = 0.19) to be heavier (848.6 g) than controls (796.2 g). Kinome analysis showed T cell receptor, TNF and NF-kB signaling pathways contributed to the improvements seen in the supplement-fed birds. The following peptides were significant (P < 0.05) in all 3 pathways: CHUK, MAP3K14, MAP3K7, and NFKB1 indicating their importance. Additionally, there were changes to IL6, IL10, and IFN- γ mRNA expression in tissue between control- and supplement-fed chickens. In conclusion, the addition of a microencapsulated blend of organic acids and botanicals to a broiler diet reduced the clinical signs of NE that was mediated by specific immune-related pathways.

In Vivo Recovery of Bacteriophages and Their Effects on Clostridium perfringens-Infected Broiler Chickens

The objectives of this study were to recover bacteriophages (BPs) from the intestinal digesta of BP-fed broilers and to evaluate the antibacterial effects of encapsulated or powdered BPs in broiler chickens challenged with Clostridium perfringens. Day-old broiler chicks (n = 320/experiment) were randomly assigned to 32 pens (n = 10 broilers/pen) and allocated to one of four dietary groups: (1) unchallenged group (NEG); (2) C. perfringens-challenged group (POS); (3) POS group fed a diet supplemented with powdered BPs; and (4) POS group fed a diet supplemented with encapsulated BPs. On days 21, 22, and 23 post-hatch, all chickens except NEG were orally inoculated twice a day with 2 mL C. perfringens (1.0 × 10⁸ cfu/mL). Varying BP levels were detected in gut digesta at all ages and were numerically or significantly higher in the encapsulated BP group than in the powdered BP group. Dietary powder or encapsulated BPs reversed the C. perfringens-mediated increase in crypt depth. In addition, villus height to crypt depth ratio was elevated in the NEG and BP-treated/challenged groups compared with that in the POS group. C. perfringens counts in the cecum were significantly lower in the BP-fed chickens than in the POS group. The encapsulated BP-supplemented diet-fed chickens had the highest serum IgA levels. Collectively, our results suggest that dietary BP remains viable in intestinal digesta upon ingestion and can inhibit cecal C. perfringens counts.

Effects of dietary glucose oxidase on growth performance and intestinal health of AA broilers challenged by Clostridium perfringens

Arbor Acre (AA) broilers were used as the research object to investigate whether glucose oxidase (GOD) has preventive and relieving effects on necrotic enteritis. The experiment was designed as a factorial arrangement of 2 dietary treatments × 2 infection states. Chickens were fed a basal diet or a diet with 150 U/kg GOD, and were challenged with Clostridium perfringens (Cp) or sterile culture medium. In our study, Cp challenge led to intestinal injury, as evidenced by reducing the average daily gain and the average daily feed intake of AA broilers of 14 to 21 d (P < 0.05), increasing the intestinal jejunal lesion score (P < 0.05), reducing the jejunal villi height and villi height/crypt depth (P < 0.05), upregulating the mRNA expression levels jejunal IFN-γ (P < 0.05). The dietary GOD had no significant effects on the growth performance of each growth period, but significantly decreased the ileal pH, increased the height of villi and the ratio of villi height to crypt depth (P < 0.05) and the expression levels of Occludin and Zonula occludens-1 (ZO-1) at d 21. Moreover, dietary GOD and the Cp challenge significantly altered the composition of 21-d ileal microbiota. The Cp challenge decreased the relative abundance of genus Lactobacillus (P = 0.057), and increased the relative abundance of genus Romboutsia (P < 0.05) and genus Veillonella (P = 0.088). The dietary GOD tended to increase the relative abundance of genus Helicobacter (P = 0.066) and decrease the relative abundance of genus Streptococcus (P = 0.071). This study has shown that the supplementation of GOD could promote the integrity of intestinal barrier and the balance of ileal microbiota, but the effects of GOD on NE broilers and its application in actual production need to be further confirmed.

Protective Effects of Lactobacillus plantarum Lac16 on Clostridium perfringens Infection-Associated Injury in IPEC-J2 Cells

Clostridium perfringens (C. perfringens) causes intestinal injury through overgrowth and the secretion of multiple toxins, leading to diarrhea and necrotic enteritis in animals, including pigs, chickens, and sheep. This study aimed to investigate the protective effects of Lactobacillus plantarum (L. plantarum) Lac16 on C. perfringens infection-associated injury in intestinal porcine epithelial cell line (IPEC-J2). The results showed that L. plantarum Lac16 significantly inhibited the growth of C. perfringens, which was accompanied by a decrease in pH levels. In addition, L. plantarum Lac16 significantly elevated the mRNA expression levels of host defense peptides (HDPs) in IPEC-J2 cells, decreased the adhesion of C. perfringens to IPEC-J2 cells, and attenuated C. perfringens-induced cellular cytotoxicity and intestinal barrier damage. Furthermore, L. plantarum Lac16 significantly suppressed C. perfringens-induced gene expressions of proinflammatory cytokines and pattern recognition receptors (PRRs) in IPEC-J2 cells. Moreover, L. plantarum Lac16 preincubation effectively inhibited the phosphorylation of p65 caused by C. perfringens infection. Collectively, probiotic L. plantarum Lac16 exerts protective effects against C. perfringens infection-associated injury in IPEC-J2 cells.

Clostridium butyricum Supplement Can Ameliorate the Intestinal Barrier Roles in Broiler Chickens Experimentally Infected With Clostridium perfringens

Necrotic enteritis (NE), caused by Clostridium perfringens, is an economically important disease in the broiler. Among normal flora in the broiler intestinal region, Clostridium butyricum has been identified as a probiotic agent that reduces the susceptibility of broilers to C. perfringens. However, the effects of C. butyricum supplement on broiler intestinal integrity during NE are largely unknown. In this study, we investigated the effects of C. butyricum on the growth performance, intestinal morphology and barrier function, and the functions of immune-related cytokines under NE in broilers. Chickens were divided into five groups: control group (NC), supplement C. butyricum only group (CB), NE-infected group (PC), supplement C. butyricum from Day 14 (NECB1) to Day 22 NE-infected group, and supplement C. butyricum from Day 1 (NECB2) to Day 22 NE-infected group. The results showed that there were significantly decreased average daily weight gain and increased feed conversion rate in the infected group (PC) compared with the C. butyricum-supplemented groups (NECB1 and NECB2) through the diet. Histopathological observation on the Hematoxylin–Eosin staining avian small intestine sections revealed that supplementation of C. butyricum (NECB1 and NECB2) could increase the intestinal villus height/crypt depth and lessen the intestinal damage under NE. ELISA and Limulus test showed that broilers infected with NE (PC) had higher serum IgA and lipopolysaccharide content; however, after C. butyricum supplementation (NECB1 and NECB2), they returned to a normal level. Furthermore, real-time PCR and Western blot results indicated that compared with PC, supplementing C. butyricum (NECB1 and NECB2) could initialize the expressions of genes related to the intestinal barrier-associated molecules (such as CLDN-1, CLDN-3, OCLN, MUC2, ZO-1, and CLDN5), cytokines (such as IL-10, IL-6, and TGFB1), and C. perfringens plc gene expression. Moreover, the results detected by the Ussing chamber suggested that C. butyricum (NECB1 and NECB2) could amend the decrease in conductivity value and short-circuit current value caused by NE. In addition, NECB2 significantly reduced the upregulation of fluorescein isothiocyanate–dextran flux caused by the NE disease. In conclusion, these findings suggest that dietary supplementation of C. butyricum in broilers with NE improved chicken growth performance, intestinal integrity and barrier function, and immunological status. Notably, no statistical difference was observed with the addition of C. butyricum on day 1 or day 14.

Increased Dietary Inclusion Levels of Lysine Are More Effective than Arginine in Supporting the Functional Status of the Gut in Growing Turkeys

Arginine (Arg) and lysine (Lys) may be important for the overall health of turkeys. The aim of this study was to determine whether low (consistent with the guidelines) and high (10% higher than recommended) levels of dietary Arg and Lys can modulate performance and the functional status of the gut. Female turkeys were allocated to four dietary treatments (two levels of Lys (low or high) and two levels of Arg (low or high)) for a 16 wk feeding period. The treatments did not affect turkey performance determined separately for four feeding phases and for the entire 16 wk experiment (p > 0.05). They had no significant influence on carcass yield, meat characteristics or the associated traits either (p > 0.05). High-Lys diets contributed to a decrease in cecal pH, a significant increase in the concentrations of short-chain fatty acids (SCFA) and a decrease in the concentrations of putrefactive SCFA and ammonia in the cecum. High dietary levels of both amino acids significantly enhanced the activity of cecal microbiota evaluated based on extracellular enzyme activity. These findings indicate that the higher dietary level of Lys was more effective in modulating the physiological status of the gut in turkeys than Arg.

Transversal gene expression panel to evaluate intestinal health in broiler chickens in different challenging conditions

There is a high interest on gut health in poultry with special focus on consequences of the intestinal diseases, such as coccidiosis and C. perfringens-induced necrotic enteritis (NE). We developed a custom gene expression panel, which could provide a snapshot of gene expression variation under challenging conditions. Ileum gene expression studies were performed through high throughput reverse transcription quantitative real-time polymerase chain reaction. A deep review on the bibliography was done and genes related to intestinal health were selected for barrier function, immune response, oxidation, digestive hormones, nutrient transport, and metabolism. The panel was firstly tested by using a nutritional/Clostridium perfringens model of intestinal barrier failure (induced using commercial reused litter and wheat-based diets without exogenous supplementation of enzymes) and the consistency of results was evaluated by another experiment under a coccidiosis challenge (orally gavaged with a commercial coccidiosis vaccine, 90× vaccine dose). Growth traits and intestinal morphological analysis were performed to check the gut barrier failure occurrence. Results of ileum gene expression showed a higher expression in genes involved in barrier function and nutrient transport in chickens raised in healthy conditions, while genes involved in immune response presented higher expression in C.perfringens-challenged birds. On the other hand, the Eimeria challenge also altered the expression of genes related to barrier function and metabolism, and increased the expression of genes related to immune response and oxidative stress. The panel developed in the current study gives us an overview of genes and pathways involved in broiler response to pathogen challenge. It also allows us to deep into the study of differences in gene expression pattern and magnitude of responses under either a coccidial vaccine or a NE.

Expression of selected genes encoding mechanistic pathways, nutrient and amino acid transporters in jejunum and ileum of broiler chickens fed a reduced protein diet supplemented with arginine, glutamine and glycine under stress stimulated by dexamethasone

Reducing crude protein and supplementation with synthetic amino acids in poultry nutrition is a recent trend to avoid wastage of protein and ammonia in production systems. Stress has been shown to impair intestinal barrier and increase inflammatory response. This study was performed on intestinal tissues of broiler chickens to understand the mechanism of stress induced by a synthetic glucocorticoid, dexamethasone (DEX) and the effect of supplementation of arginine, glutamine and glycine in reduced protein diets. Intestinal tissue samples from a previous study were utilized. Male Ross 308 chickens received a basal diet for the first seven days and then fed with crude protein that was reduced to 194 g/kg in grower experimental diets supplemented with glutamine, glycine and additional arginine at 10, 10 and 5 g/kg respectively. Half of the 96 individual birds were injected with DEX (0.5 mg/kg body weight) or saline on days 14, 16, 18 and 20 of age. mRNA expression for jejunum and ileum for amino acid transporters (y+LAT-1, B^o,+ AT, EAAT-3 and CAT-1), mechanistic genes (SGLT-1, mTOR, IAP and FABP-2) and pro-inflammatory genes (MUC-2, NF-κB, iNOS, IL-8 and IL-1β) were analysed using real-time PCR. The results showed that DEX decreased y+ LAT1 in jejunum, B^{o ,+} AT and EAAT-3 in ileum. Arginine increased CAT-1 in the jejunum and ileum under DEX treatment. Through an interaction, DEX reduced IAP in jejunum of glycine and arginine supplemented group and reduced mTOR in jejunum independently. DEX reduced MUC-2 and iNOS in jejunum and increased iNOS and IL8 in the ileum. Amino acid supplementation did not appear to ameliorate these effects; however, there were some positive effects of glycine on NF-κB and arginine through increased CAT-1. Mechanistic understanding of amino acid supplementation in broiler diets warrants further research particularly when dietary protein is reduced below the level tested in the present study.

Spotlight on avian pathology: untangling contradictory disease descriptions of necrotic enteritis and necro-haemorrhagic enteritis in broilers

Necrotic enteritis (NE) is one of the most detrimental infectious diseases in the modern poultry industry, characterized by necrosis in the small intestine. It is commonly accepted that NetB-producing C. perfringens type G strains are responsible for the disease. However, based on both macroscopic and histopathological observations, two distinct types of NE are observed. To date, both a haemorrhagic form of NE and the type G-associated non-haemorrhagic disease entity are commonly referred to as NE and the results from scientific research are interchangeably used, without distinguishing between the disease entities. Therefore, we propose to rename the haemorrhagic disease entity to necro-haemorrhagic enteritis.

Probiotics mitigating subclinical necrotic enteritis (SNE) as potential alternatives to antibiotics in poultry

Subclinical necrotic enteritis (SNE) caused by Clostridium perfringens (CP), is an important disease in chickens, which causes huge economic losses by damaging the intestinal mucosa, decreasing digestion and absorption of nutrients. Use of antibiotics at a sub-therapeutic level as antimicrobial growth promoters in poultry feed prevents the birds from SNE and improves growth. Due to the ban on the use of antibiotics in 2006 as antimicrobial growth promoters have led to the reemergence of the disease. Worldwide numerous studies have been carried out to investigate the alternatives to antibiotics for the prevention of SNE. Possible alternatives to control SNE include probiotics, prebiotics, bacteriophages, essential oils, organic acids, secondary metabolites and other microbial products. Currently, probiotics are most extensively used in poultry production as an alternative to antibiotics. This review summarizes recent insights and experimental evidence on the use of different microorganisms like Bacillus, Lactic acid bacteria, Bifidobacteria, Enterococcus, yeast, etc. as valuable probiotics for prevention of SNE and potential molecular mechanisms responsible for ameliorating effects of probiotics against SNE.

Dexmedetomidine Exerts Brain-Protective Effects Under Cardiopulmonary Bypass Through Inhibiting the Janus Kinase 2/Signal Transducers and Activators of Transcription 3 Pathway

Brain injury is a major complication resulted from cardiopulmonary bypass (CPB). Dexmedetomidine (DEX) has potential brain-protective effects; however, the mechanism is unclear. The aim of this study is to investigate the effect of DEX on brain injury in CPB rats and its mechanism. The levels of interleukin-6 (IL-6), interleukin-10 (IL-10), S100β, and neuron-specific enolase (NSE) were measured by enzyme-linked immunosorbent assay. The hippocampus CA1 region in rats was observed by hematoxylin-eosin staining. Western blot and quantitative real-time polymerase chain reaction were performed to detect related proteins and mRNA expressions in the hippocampus tissues. We found that after CPB, the neuron cells in hippocampus CA1 region of rats were randomly arranged, and that the levels of IL-6, IL-10, S100β, NSE, Cleaved Caspase-3, and Bax were upregulated, while Bal-2 level was downregulated. However, after DEX treatment, the neuron cells arranged in an orderly manner, and the levels of IL-6, IL-10, S100β, NSE, Cleaved Caspase-3, and Bax were downregulated, but Bal-2 level was upregulated. DEX suppressed Janus kinase 2 (JAK2)/signal transducers and activators of transcription 3 (STAT3) pathway activated by CPB, ameliorated CPB-induced brain injury in rats by reducing inflammatory response, and inhibited neuronal apoptosis. The brain-protective effect of DEX may be related to the inhibition of the activation of JAK2/STAT3 pathway.