Interaction of TGF-β4 and IL-17 with IgA secretion in the intestine of chickens fed with E. faecium AL41 and challenged with S. Enteritidis

Effects of Mink-Origin Enterococcus faecium on Growth Performance, Antioxidant Capacity, Immunity, and Intestinal Microbiota of Growing Male Minks

The purpose of this experiment was to explore the effects of dietary Enterococcus faecium (EF) on the growth performance, antioxidant capacity, immunity, and intestinal microbiota of growing male minks. A total of 60 male Regal White minks at 12 weeks of age were randomly assigned to two groups, each with 15 replicates of two minks per replicate. The minks in two groups were fed the basal diets and the basal diets with viable Enterococcus faecium (more than 107 cfu/kg of diet), respectively. Compared with the minks in control, Enterococcus faecium minks had heavier body weight (BW) at week 4 and week 8 of the study (p < 0.05), greater average daily gain (ADG), and a lower feed/gain ratio (F/G) of male minks during the initial 4 weeks and the entire 8-week study period (p < 0.05). Furthermore, Enterococcus faecium increased the apparent digestibility of crude protein (CP) and dry matter (DM) compared to the control (p < 0.05). Moreover, Enterococcus faecium enhanced the serum superoxide dismutase (SOD) activity and decreased the malondialdehyde (MDA) contents (p < 0.05). The results also confirmed that Enterococcus faecium increased the levels of serum immunoglobulin A (IgA), immunoglobulin G (IgG), and the concentrations of secretory immunoglobulin A (SIgA) in the jejunal mucosa while decreasing the interleukin-8 (IL-8) and interleukin-1β (IL-1β) levels in the jejunal mucosa (p < 0.05). Intestinal microbiota analysis revealed that Enterococcus faecium increased the species numbers at the OUT level. Compared with the control, Enterococcus faecium had significant effects on the relative abundance of Paraclostridium, Brevinema, and Comamonas (p < 0.05). The results showed that Enterococcus faecium could improve the growth performance, increase the antioxidant capacity, improve the immunity of growing male minks, and also modulate the gut microbiota.

Prophylactic and Therapeutic Efficacy of Ultrasonicated Rosmarinus officinalis Ethanolic Extract and its Chitosan-Loaded Nanoparticles Against Eimeria tenella Infected Broiler Chickens

PURPOSE

The in vivo efficacy of ultrasonicated Rosmarinus officinalis ethanolic extract (UROEE) and its chitosan-loaded nanoparticles (UROEE-CsNPs) was investigated as a dietary prophylactic agent and as a therapeutic treatment against Eimeria tenella infected broiler chickens.

METHODS

Chickens were infected with 4 × 104 E. tenella oocysts at 21 days old for primary infection and with 8 × 104 oocysts at 35 days old for secondary infection. Eleven experimental groups were conducted. Dietary addition of 100 mg/kg UROEE and 20 mg/kg for CsNPs as well as UROEE-CsNPs were included for prophylactic groups from day 1 to 42. The same doses were used for therapeutic treatment groups for 5 constitutive days. Oocyst output in feces was counted. Histopathological and immunohistochemical studies were conducted. Gene expression of pro-inflammatory cytokines as IFN-γ, IL-1β and IL-6 as well as anti-inflammatory cytokines as IL-10 and TGF-β4 was analyzed using semi-quantitative reverse transcriptase-PCR.

RESULTS

The results showed an efficacy of UROEE, CsNPs and UROEE-CsNPs in reduction of oocyst excretion and improving the cecal tissue architecture. CD4+ and CD8+ T lymphocytes protein expression were reduced. E. tenella infection lead to upregulation of pro-inflammatory cytokines as IFN-γ, IL-1β, IL-6 and anti-inflammatory cytokines as TGF-β4 following primary infection, while their expression was downregulated following secondary infection.

CONCLUSION

The dietary prophylactic additives and therapeutic treatments with UROEE, CsNPs and UROEE-CsNPs could decrease the inflammatory response to E. tenella as indicated by oocyst output reduction, histopathological improvements, CD4+ and CD8+ T cells protein expression reduction as well as reducing mRNA expression levels of the tested cytokines following primary and secondary infections. Consequently, these results will help to develop better-combating strategies for the control and prevention of coccidiosis on poultry farms as a dietary prophylactic agent or as a therapeutic treatment.

Genome-wide association studies of parasite resistance, productivity and immunology traits in Scottish Blackface sheep

Gastrointestinal parasitism represents a global problem for grazing ruminants, which can be addressed sustainably by breeding animals to be more resistant against infection by parasites. The aim of this study was to assess the genetic architecture underlying traits associated with gastrointestinal parasite resistance, immunological profile and production in meat sheep, and identify and characterise candidate genes affecting these traits. Data on gastrointestinal parasite infection (faecal egg counts for Strongyles (FECS) and Nematodirus (FECN) and faecal oocyst counts for Coccidia, along with faecal soiling scores (DAG), characterised by the accumulation of faeces around the perineum) and production (live weight (LWT)) were gathered from a flock Scottish Blackface lambs at three and four months of age. Data on the immune profile were also collected from a subset of these lambs at two and five months of age. Immune traits included the production of Interferon-γ (IFN-γ), Interleukin (IL)-4 and IL-10 following stimulation of whole blood with pokeweed mitogen (PWM) or antigen from the gastric parasite Teladorsagia circumcincta (T-ci), and serum levels of T. circumcincta-specific immunoglobulin A (IgA). Animals were genotyped with genome-wide DNA arrays, and a total of 1 766 animals and 45 827 Single Nucleotide Polymorphisms (SNPs) were retained following quality control and imputation. Genome-wide association studies were performed for 24 traits. The effects of individual markers with significant effects were estimated, and the genotypic effect solutions were used to estimate additive and dominance effects, and the proportion of additive genetic variance attributed to each SNP locus. A total of 15 SNPs were associated at least at a suggestive level with FECS, FECN, DAG, IgA, PWM-induced IFN-γ and IL-4, and T-ci-induced IL-10. This study uncovered 52 genes closely related to immune function in proximity to these SNPs. A number of genes encoding C-type lectins and killer cell lectin-like family members were close to a SNP associated with FECN, while several genes encoding IL-1 cytokine family members were found to be associated with IgA. Potential candidate genes belonging to or in close proximity with the Major Histocompatibility Complex (MHC) were revealed, including Homeostatic Iron Regulator and butyrophilin coding genes associated with IFN-γ(PWM), and IL-17 coding genes associated with IgA. Due to the importance of the MHC in the control of immune responses, these genes may play an important role in resistance to parasitic infections. Our results reveal a largely complex and polygenic genetic profile of the studied traits in this Scottish Blackface sheep population.

Measuring Chronic Stress in Broiler Chickens: Effects of Environmental Complexity and Stocking Density on Immunoglobulin-A Levels

Commercial housing conditions may contribute to chronic negative stress in broiler chickens, reducing their animal welfare. The objective of this study was to determine how secretory (fecal) and plasma immunoglobulin-A (IgA) levels in fast-growing broilers respond to positive and negative housing conditions. In three replicated experiments, male Ross 708 broilers (n = 1650/experiment) were housed in a 2 × 2 factorial study of high or low environmental complexity and high or low stocking density. In experiments 1 and 3 but not in experiment 2, high complexity tended to positively impact day 48 plasma IgA concentrations. When three experiments were combined, high complexity positively impacted day 48 plasma IgA concentrations. Stocking density and the complexity × density interaction did not impact day 48 plasma IgA concentrations. Environmental complexity and the complexity × density interaction did not impact day 48 secretory IgA concentrations. A high stocking density negatively impacted day 48 secretory IgA concentrations overall but not in individual experiments. These results suggest that environmental complexity decreased chronic stress, while a high stocking density increased chronic stress. Thus, plasma IgA levels increased under high-complexity housing conditions (at day 48), and secretory IgA levels (at day 48) decreased under high-density conditions, suggesting that chronic stress differed among treatments. Therefore, these measures may be useful for quantifying chronic stress but only if the statistical power is high. Future research should replicate these findings under similar and different housing conditions to confirm the suitability of IgA as a measure of chronic stress in broiler chickens.

A review on circular RNAs and bacterial infections

Bacterial infections and related diseases have been a major burden on social public health and economic stability around the world. However, the effective diagnostic methods and therapeutic approaches to treat bacterial infections are still limited. As a group of non-coding RNA, circular RNAs (circRNAs) that were expressed specifically in host cells and played a key regulatory role have the potential to be of diagnostic and therapeutic value. In this review, we systematically summarize the role of circRNAs in common bacterial infections and their potential roles as diagnostic markers and therapeutic targets.

Pretreatment with probiotics Enterococcus faecium NCIMB 11181 attenuated Salmonella Typhimurium-induced gut injury through modulating intestinal microbiome and immune responses with barrier function in broiler chickens

Background

Preventing Salmonella infection and colonization in young birds is key to improving poultry gut health and reducing Salmonella contamination of poultry products and decreasing salmonellosis for human consumption (poultry meat and eggs). Probiotics can improve poultry health. The present study was conducted to investigate the impact of a probiotics, Enterococcus faecium NCIMB 11181 (E. faecium NCIMB 11181) on the intestinal mucosal immune responses, microbiome and barrier function in the presence or absence of Salmonella Typhimurium (S. Typhimurium, ST) infection.

Methods

Two hundred and forty 1-day-old Salmonella-free male broiler chickens (Arbor Acres AA⁺) were randomly allocated to four groups with 6 replicate cages of 10 birds each. The four experimental groups were follows: (1) negative control (NC), (2) S. Typhimurium, challenged positive control (PC), (3) the E. faecium NCIMB 11181-treated group (EF), (4) the E. faecium NCIMB 11181-treated and S. Typhimurium-challenged group (PEF).

Results

Results indicated that, although continuous feeding E. faecium NCIMB 11181 did not obviously alleviate growth depression caused by S. Typhimurium challenge (P > 0.05), E. faecium NCIMB 11181 addition significantly blocked Salmonella intestinal colonization and translocation (P < 0.05). Moreover, supplemental E. faecium NCIMB 11181 to the infected chickens remarkably attenuated gut morphological structure damage and intestinal cell apoptosis induced by S. Typhimurium infection, as evidenced by increasing gut villous height and reducing intestinal TUNEL-positive cell numbers (P < 0.05). Also, E. faecium NCIMB 11181 administration notably promoting the production of anti-Salmonella antibodies in intestinal mucosa and serum of the infected birds (P < 0.05). Additionally, 16S rRNA sequencing analysis revealed that E. faecium NCIMB 11181 supplementation ameliorated S. Typhimurium infection-induced gut microbial dysbiosis by enriching Lachnospiracease and Alistipes levels, and suppressing Barnesiella abundance. Predicted function analysis indicated that the functional genes of cecal microbiome involved in C5-branched dibasic acid metabolism; valine, leucine and isoleucine biosynthesis; glycerolipid metabolism and lysine biosynthesis were enriched in the infected chickens given E. faecium NCIMB 11181. While alanine, asparate and glutamate metabolism; MAPK signal pathway-yeast; ubiquine and other terpenoid-quinore biosynthesis, protein processing in endoplasmic reticulum; as well as glutathione metabolism were suppressed by E. faecium NCIMB 11181 addition.

Conclusion

Collectively, our data suggested that dietary E. faecium NCIBM 11181 supplementation could ameliorate S. Typhimurium infection-induced gut injury in broiler chickens. Our findings also suggest that E. faecium NCIMB 11181 may serve as an effective non-antibiotic feed additive for improving gut health and controlling Salmonella infection in broiler chickens.

The Effect of Enterococcus faecium AL41 on the Acute Phase Proteins and Selected Mucosal Immune Molecules in Broiler Chickens

Probiotic bacteria, including the Enterococcus faecium strain, can improve intestinal mucosal health by several mechanisms, including modulation of the immune response, as well as by improving the protective function of the epithelial barrier. In this study, we tested the effect of Enterococcus faecium AL41 on the acute phase proteins response (blood), gene expression of selected molecules of mucosal immunity (immunoglobulin A, mucin-2, insulin-like growth factor 2) and mucus production (all parts of the small intestine) in broilers. Eighty broiler chicks were divided into two groups: a control and E. faecium AL41 (birds were inoculated with AL41 for 7 days) group. The whole experiment lasted 11 days. Our results revealed that the administration of E. faecium AL41 had no substantial effect on the concentrations of acute phase proteins, but we recorded a significant increase in β- and γ-globulin fractions at the end of the experiment, which may indicate an improvement in the immune status. A significant prolonged stimulatory effect of E. faecium AL41 on the relative expression of molecules (immunoglobulin A, mucin-2) as well as on the dynamic of mucus production in the chicken intestine was observed. In addition, AL41 significantly reduced the total number of enterococci in the cecum and faeces.

Influence of Immune Parameters after Enterococcus faecium AL41 Administration and Salmonella Infection in Chickens

Immune response of day-old chicks infected with Salmonella Enteritidis PT4 and preventive administration of Enterococcus faecium AL41 were studied using hematology and flow cytometry of immunocompetent cells in blood, cecum, bursa and spleen for 11 days, and included 220 animals divided into four groups (n = 55). E. faecium AL41 was administered for 7 days to EF and EFSE groups and on day 4 SE and EFSE groups were infected with Salmonella Enteritidis. Values of monocytes at 4 dpi significantly increased in EFSE and lymphocytes at 7 dpi in EF groups. Blood CD3, CD4, CD8 and IgM lymphocytes improved in EF and EFSE groups and IgA in EF group at 4 dpi. Phagocytic activity of probiotic groups was improved in both samples. Cecal IEL and LPL lymphocytes showed at 7 dpi stimulation of CD3, CD4 and CD8 subpopulations in probiotic groups, especially in EFSE group, IgA IEL and IgA with IgM LPL in EF groups. Bursa Fabricii at 7 dpi presented overstimulation of IgG subpopulation in SE group, spleen CD3 and CD8 in EF and EFSE groups. E. faecium AL41 revealed the protective effect and positive influence on the local and systemic immune response in Salmonella Enteritidis PT4 infected chickens.

Effects of dietary supplementation with a laminarin-rich extract on the growth performance and gastrointestinal health in broilers

Restriction in antimicrobial use in broiler chicken production is driving the exploration of alternative feed additives that will support growth through the promotion of gastrointestinal health and development. The objective of this study was to determine the effects of dietary inclusion of laminarin on growth performance, the expression of nutrient transporters, markers of inflammation and intestinal integrity in the small intestine and composition of the caecal microbiota in broiler chickens. Two-hundred-and-forty day-old male Ross 308 broiler chicks (40.64 (3.43 SD) g) were randomly assigned to: (T1) basal diet (control); (T2) basal diet + 150 ppm laminarin; (T3) basal diet + 300 ppm laminarin (5 bird/pen; 16 pens/treatment). The basal diet was supplemented with a laminarin-rich Laminaria spp. extract (65% laminarin) to achieve the two laminarin inclusion levels (150 and 300 ppm). Chick weights and feed intake was recorded weekly. After 35 days of supplementation, one bird per pen from the control and best performing (300 ppm) laminarin groups were euthanized. Duodenal, jejunal and ileal tissues were collected for gene expression analysis. Caecal digesta was collected for microbiota analysis (high-throughput sequencing and QPCR). Dietary supplementation with 300 ppm laminarin increased both final body weight (2033 vs. 1906 ± 30.4, P < 0.05) and average daily gain (62.3 vs. 58.2 ± 0.95, P < 0.05) compared to the control group and average daily feed intake (114.1 vs. 106.0 and 104.5 ± 1.77, P < 0.05) compared to all other groups. Laminarin supplementation at 300 ppm increased the relative and absolute abundance of Bifidobacterium (P < 0.05) in the caecum. Laminarin supplementation increased the expression of interleukin 17A (IL17A) in the duodenum, claudin 1 (CLDN1) and toll-like receptor 2 (TLR2) in the jejunum and IL17A, CLDN1 and SLC15A1/peptide transporter 1 (SLC15A1/PepT1) in the ileum (P < 0.05). In conclusion, supplementation with laminarin is a promising dietary strategy to enhance growth performance and 300 ppm was the optimal inclusion level with which to promote a beneficial profile of the gastrointestinal microbiota in broiler chickens.

Influence of Lacto-Immuno-Vital on growth performance and gene expression of IgA, MUC-2, and growth factor IGF-2 in the jejunum of broiler chickens

The effects of Lacto-Immuno-Vital synbiotic preparation on gene expression of IgA, MUC-2, and growth factor IGF-2 in the jejunum and on BW gain in broiler chickens were studied. A flock of 64,400 1-day-old Hybrid ROSS 308 chickens was inducted in the 42-day experiment. The chickens were divided into 2 equally size groups in separate halls. The chickens in the experimental (E) group received 500 g of Lacto-Immuno-Vital in 1,000 L of drinking water. The preparation was administered daily from the first day (day 1) to day 7 of the experiment. From day 7 to day 22, it was given in pulsed manner (every third day) at a dose of 300 g in 1,000 L of drinking water. The broiler chickens in the E group gained more weight (P < 0.001) compared with control from day 10 to day 42. Death of animals during feeding period was 1,078 chickens in the E group compared with 1,115 dead chickens in the control group. Feed conversion ratio was 1.61 kg of supplemented diet/kg of BW in the E group compare with 1.67 kg of nonsupplemented diet/kg of BW in control. The relative expression of IgA gene in the jejunum was upregulated on day 22 in the E group compared with control (P < 0.05), whereas relative expression of MUC-2 gene was upregulated in the E group compared with control on day 8 and day 22 (P < 0.05; P < 0.001). Similarly, relative expression of IGF-2 gene was upregulated in the E group compared with control on both samplings (P < 0.01). The composition of Lacto-Immuno-Vital synbiotic preparation showed beneficial effects on growth performance, feed conversion ratio, morbidity, mortality, and selected parameters of mucosal immunity in the chicken jejunum.

Effect of Tourist Activities on Fecal and Salivary Glucocorticoids and Immunoglobulin A in Female Captive Asian Elephants in Thailand

Simple Summary

How tourist camp activities affect individual elephant welfare is an important and highly debated topic. Saliva and fecal samples were collected monthly for 1 year from 44 female Asian elephants that participated in three programs (saddle-, bareback-, or no-riding), and analyzed for glucocorticoids (GC) and immunoglobulin A (IgA). The hypothesis was that better welfare would be associated with low GC and high IgA concentrations. Both biomarkers showed significant variation with respect to camp size, riding activities, tourist-to-elephant ratios and seasonality, but not always consistently between feces and saliva, and not always in the predicted direction. However, there was no clear indication that riding per se negatively affected these two biomarkers. The lack of consistent responses highlights the difficulty in interpreting physiological data in relation to management factors, and suggests more work is needed to differentiate between potential chronic (feces) and acute (saliva) responses.

Abstract

Asian elephants have been an important part of wildlife ecotourism in Thailand for over two decades. Elephants in tourist camps are exposed to a variety of management styles and daily activities that can potentially affect health and welfare. This study investigated relationships between a novel welfare biomarker, immunoglobulin A (IgA), and daily camp activities, and compared results to glucocorticoid (GC) measures. Often no-riding camps are portrayed as providing better welfare than camps that offer riding. Therefore, we predicted that elephants at no-riding camps would have lower GC and higher IgA concentrations, and a low GC/IgA ratio. Forty-four female elephants from six elephant camps were divided into three groups based on riding activities: saddle-riding, bareback-riding, and no-riding. Fecal and salivary samples were collected monthly for 1 year along with evaluations of body condition, foot health, and wounding. Camp environment and management varied among camps, although the major difference was in riding activities. Concentrations of GCs and IgA varied among the working groups, but not always consistently between sample matrices. Overall fecal glucocorticoid metabolite concentrations were lowest in the saddle-riding group. Only in one bareback-riding camp did the elephants exhibit a potentially positive welfare response with a low GC/IgA ratio over time. Other results varied between the two biomarkers, with considerable variability across camps, suggesting there is more to good welfare than whether elephants participate in riding or not. Several other human-induced stressors, like chaining, ankus use, and limited social opportunities are likely to be impacting well-being and should be considered to ensure management practices meet physical and psychological welfare needs.

Pretreatment with probiotic Enterococcus faecium NCIMB 11181 ameliorates necrotic enteritis-induced intestinal barrier injury in broiler chickens

The dysfunction of tight-junction integrity caused by necrotic enteritis (NE) is associated with decreased nutrient absorption and gut injury in broiler chickens. Although probiotic Enterococcus faecium (E. faecium) has been reported to possess immune-regulatory characteristics and can prevent diarrhea in pigs, very little information exists in relation to the specific regulatory impact of E. faecium NCIMB 11181 on NE-induced intestinal barrier injury of broiler chickens. This study was conducted to investigate the protective effects of probiotic E. faecium NCIMB 11181 on NE-induced intestinal barrier injury in broiler chickens. The study also aimed to elucidate the mechanisms that underpin these protective effects. One hundred and eighty Arbor Acres (AA) broiler chicks (one day old) were randomly assigned using a 2 × 2 factorial arrangement into two groups fed different levels of dietary E. faecium NCIMB 11181 (0 or 2 × 10⁸ CFU/kg of diet) and two disease-challenge groups (control or NE challenged). The results showed that NE induced body weight loss, intestinal lesions, and histopathological inflammation, as well as intestinal-cell apoptosis. These symptoms were alleviated following the administration of probiotic E. faecium NCIMB 11181. Pretreatment with probiotic E. faecium NCIMB 11181 significantly upregulated the expression of the Claudin-1 gene encoding a tight-junction protein. Claudin-1 and HSP70 protein expression were also increased in the jejunum regardless of NE infection. Furthermore, NE-infected birds fed with E. faecium displayed notable increases in MyD88, NF-κB, iNOS, PI3K, GLP-2, IL-1β, IL-4, and HSP70 mRNA expression. E. faecium NCIMB 11181 administration also significantly improved the animals’ intestinal microbial composition regardless of NE treatment. These findings indicated that addition of E. faecium NCIMB 11181 to poultry feed is effective in mitigating NE-induced gut injury, possibly by strengthening intestinal mucosal barrier function, as well as modulating gut microflora and intestinal mucosal immune responses.

Cecal CircRNAs Are Associated With the Response to Salmonella Enterica Serovar Enteritidis Inoculation in the Chicken

Circular RNAs (circRNAs) are a class of endogenous noncoding RNA, which is different from linear RNA. CircRNA is an RNA molecule with a closed loop structure formed by reverse splicing. CircRNAs have been studied in several organisms, however, the circRNAs associated with the response to Salmonella enterica serovar Enteritidis (SE) inoculation in chickens are still unclear. In the current study, Jining Bairi chickens were inoculated with SE. CircRNAs involved in the response to SE inoculation were identified through next-generation sequencing. Our results showed that there were 5,118 circRNAs identified in the control and treated groups. There were 62 circRNAs significantly differentially expressed following SE inoculation. Functional classification revealed that those significantly differentially expressed circRNAs were associated with immune system process, rhythmic process and signaling following SE inoculation. CircRNAs NC_006091.4: 65510578|65515090, NC_006099.4: 16132825|16236906, and NC_006099.4: 15993284|16006290 play important roles in the response to SE inoculation. The findings in the current study provide evidence that circRNA alterations are involved in the response to SE inoculation in the chicken.

Identification of Serum Biomarkers for Intestinal Integrity in a Broiler Chicken Malabsorption Model

Intestinal health is essential for feed efficiency and growth in animal agriculture and is dependent on barrier function, inflammation and dysbiosis. Our laboratory has published a nutritional model to induce gut inflammation using rye as a source of energy in poultry. More recently, we have used this model as an assessment of a nutritional rehabilitation model for better understanding of childhood undernutrition. The objective of this brief research report was to use a well-establish malabsorption model in broiler chickens using corn and rye as an energy source to identify several intestinal health biomarkers in the serum. To screen for inflammatory biomarkers, seven commercially available tests were used including Griess, superoxide dismutase, thiobarbituric acid reactive substances, Total antioxidant capacity, extracellular-signal-regulated kinase, Citrulline, and Interferon-ɤ; total IgA from cloacal swab was also measured. In the present study, chickens fed rye had a significant (P < 0.05) reduction in body weight and body weight gain at 10 day when compared with chickens that received the corn diet. In the second phase of the experiment, chickens that remain with the corn diet had significant differences in body weight and body weight gain. No significant differences were observed for any of the four antioxidant biomarkers evaluated in the sera (P > 0.05). However, significant differences were observed in serum citrulline and IFN-ɤ, as well as in cloacal IgA, in broiler chickens fed with rye, suggesting their potential use as biomarkers to study intestinal inflammation.

Muscle characteristics in chicks challenged with Salmonella Enteritidis and the effect of preventive application of the probiotic Enterococcus faecium

The present study was conducted to assess the effects of the probiotic Enterococcus faecium AL41 (EF) and of the enteric pathogen Salmonella Enteritidis PT4 (SE) on the development of posthatch pectoralis major muscle (PM) of broiler chicks. The four experimental groups were control (CON), EF, SE, and EF+SE (EFSE). EF and SE were given per os from days 1 to 7 and at day 4 posthatch, respectively. Muscle samples from 6 chicks per group were taken at day 8 (D8) and day 11 (D11) to evaluate PM myofiber growth, capillarization, DNA, RNA, and protein content, as well as enzyme activities (isocitrate dehydrogenase, lactate dehydrogenase, creatine kinase). PM growth rate was 7.45 ± 2.7 g/d in non-SE groups (CON, EF) and 5.10 ± 1.82 g/d in SE-infected groups (P < 0.02). Compared with group CON, application of bacteria (groups EF and SE) reduced the fiber cross-sectional area (246 and 262 vs. 347 ± 19 μm2) and the number of myonuclei per fiber (0.66 and 0.64 vs. 0.79 ± 0.03). At D11, hypertrophic myofiber growth normalized in the EF group, but negative effects persisted in SE and EFSE birds contributing to lower daily PM gain. In addition, SE infection strongly disturbed PM capillarization. Negative effects on capillary cross-sectional area and on the area (%) covered by capillaries persisted until D11 in the SE group, whereas pre-feeding of EF restored capillarization in the EFSE group to control levels. We conclude that supplementation of the probiotic bacteria EF AL41 had positive effects on PM capillarization and, thus, on delivery of O2, supply of nutrients, and removal of metabolites. Supplementation of probiotic bacteria might therefore reduce energetic stress and improve muscle health and meat quality during SE infection.

The effects of the supplementation of multi-strain probiotics on intestinal microbiota, metabolites and inflammation of young SPF chickens challenged with Salmonella enterica subsp. enterica

This study assessed the effect of probiotics on cecal microbiota, cecal short-chain fatty acids (SCFAs), and the gene expression of cytokines in young specific-pathogen-free (SPF) chickens infected with S. enterica subsp. enterica. One-day-old SPF chickens (n = 105) were randomly assigned to one of the three treatment groups: control (Cont) group, Salmonella-infected (Sal) group, and a Salmonella-infected group treated with multi-strain probiotics (ProSal group). All chickens except those in the Cont group were challenged orally with 1 × 10⁸  cfu/ml of Salmonella 4 days after hatching. Chickens in the Sal group exhibited more abundance of Proteobacteria than those in the Cont and ProSal groups. At the genus level, chickens in ProSal group exhibited increased numbers of Lactobacillus and Oscillospira compared with those in the other groups. Chickens in the ProSal group exhibited a significant increase of cecal SCFAs compared with chickens in the Sal group. Chickens in the ProSal group exhibited increased gene expression of anti-inflammatory cytokines, IL-10 and TGF-β4, and decreased expression of the proinflammatory cytokine, IFN-γ, in the cecal tonsil compared with those in the Sal group. The results of this study indicated that the administration of probiotics can modulate microbiota, SCFAs, and immunomodulatory activity in SPF chickens.

Cecal microbiome profile altered by Salmonella enterica, serovar Enteritidis inoculation in chicken

Background

Salmonella enterica, serovar Enteritidis (S. Enteritidis), an important zoonotic foodborne pathogen, can affect the microbiota of the chicken intestine and cause many enteric diseases, such as acute gastroenteritis. The gut microbiota contributes to the development and function of the host immune system and competes with pathogenic microbes. The interaction between S. Enteritidis and the host cecal microbiota is still not fully understood. We investigated the microbiome composition in both treated and control groups through 16S ribosomal RNA (rRNA) gene sequencing at 1, 3, 7, 14, 21, 28, and 35 days post-S. Enteritidis inoculation (dpi) in the current study.

Results

Chao1 richness and Shannon diversity significantly increased with chicken development in both the treated and control groups (P < 0.05). The Chao1 index was significantly lower in the treated group than that in the control group at 14 dpi (P < 0.05). Phyla Proteobacteria and Firmicutes were most dominant at 1 and 3 dpi. S. Enteritidis inoculation influenced cecal microbiota mainly at 7 and 14 dpi. S. Enteritidis inoculation significantly altered the relative abundance of 18 genera at different time points (P < 0.05) with relative abundance significantly changed after 14 dpi. The abundance of those genera changed dramatically between 28 and 35 dpi in the treated group compared to control group. Positive correlations existed between Bacillus and Blautia and between Coprococcus and Flavonifractor following S. Enteritidis inoculation.

Conclusions

Our results indicated that both development and S. Enteritidis have effect on chicken cecal microbiota profiles. S. Enteritidis inoculation in young chicks influences the cecal microbiota mainly at 7 and 14 dpi. The cecal microbiota exhibited immunity to S. Enteritidis inoculation at 28 dpi. These findings will provide basic knowledge of the role that chicken cecal microbiota play in response to S. Enteritidis inoculation.

Immunogenicity and safety of a live Riemerella anatipestifer vaccine and the contribution of IgA to protective efficacy in Pekin ducks

Riemerella anatipestifer (RA) infections cause major economic losses in the duck industry. In this study, we developed an RA vaccine to control virulent serotype 1 and 2 RA, which predominate in worldwide prevalence. We established a strategy for vaccine candidate screening, and selected strains D15-RDA-92 (serotype 1) and D14-RDA-8 (serotype 2). These strains were characterized by ≤50% embryo mortality and <3.0 serum resistance assay values in in vitro screening. We evaluated the protective efficacy of live bivalent RA vaccines against virulent homologous serotype RA. Ducklings received two oral immunizations with the bivalent vaccine and showed significant protection against two virulent strains (serotypes 1 and 2) at 21 days post-immunization. No death or clinical signs of diarrhea, tremors, or limb swelling were observed in the immunized ducks. In a safety evaluation, ducks immunized with 100 times higher doses showed no clinical signs, mortality, gross lesions, or histological lesions, and body weight of the ducks showed no significant difference compared to that of negative controls. In addition, IgA analysis showed a significant increase in secretory IgA antibodies generated in the trachea and duodenum of orally immunized ducks at 28 days of age. The IgA might be involved in one of the major immune responses to RA and contributes to protecting against virulent RA. In this study, we developed monovalent and bivalent RA vaccines that were safe in ducks and provided significant protective efficacy against virulent homologous RA strains.

Linking stress and immunity: Immunoglobulin A as a non-invasive physiological biomarker in animal welfare studies

As the animal welfare community strives to empirically assess how care and management practices can help maintain or even enhance welfare, the development of tools for non-invasively measuring physiological biomarkers is essential. Of the suite of physiological biomarkers, Immunoglobulin A (IgA), particularly the secretory form (Secretory IgA or SIgA), is at the forefront because of its crucial role in mucosal immunity and links to physical health, stress, and overall psychological well-being. While interpretation of changes in SIgA concentrations on short time scales is complex, long-term SIgA patterns are consistent: conditions that create chronic stress lead to suppression of SIgA. In contrast, when welfare is enhanced, SIgA is predicted to stabilize at higher concentrations. In this review, we examine how SIgA concentrations are reflective of both physiological stress and immune function. We then review the literature associating SIgA concentrations with various metrics of animal welfare and provide detailed methodological considerations for SIgA monitoring. Overall, our aim is to provide an in-depth discussion regarding the value of SIgA as physiological biomarker to studies aiming to understand the links between stress and immunity.

Effects of rye inclusion in grower diets on immune competence-related parameters and performance in broilers

An experiment was conducted to investigate the effects of dietary inclusion of rye, a model ingredient to increase gut viscosity, between 14 and 28 d of age on immune competence-related parameters and performance of broilers. A total of 960 day-old male Ross 308 chicks were weighed and randomly allocated to 24 pens (40 birds per pen), and the birds in every 8 replicate pens were assigned to 1 of 3 experimental diets including graded levels, 0%, 5%, and 10% of rye. Tested immune competence-related parameters were composition of the intestinal microbiota, genes expression in gut tissue, and gut morphology. The inclusion of 5% or 10% rye in the diet (d 14 to 28) resulted in decreased performance and litter quality, but in increased villus height and crypt depth in the small intestine (jejunum) of the broilers. Relative bursa and spleen weights were not affected by dietary inclusion of rye. In the jejunum, no effects on number and size of goblet cells, and only trends on microbiota composition in the digesta were observed. Dietary inclusion of rye affected expression of genes involved in cell cycle processes of the jejunal enterocyte cells, thereby influencing cell growth, cell differentiation and cell survival, which in turn were consistent with the observed differences in the morphology of the gut wall. In addition, providing rye-rich diets to broilers affected the complement and coagulation pathways, which among others are parts of the innate immune system. These pathways are involved in eradicating invasive pathogens. Overall, it can be concluded that inclusion of 5% or 10% rye to the grower diet of broilers had limited effects on performance. Ileal gut morphology, microbiota composition of jejunal digesta, and gene expression profiles of jejunal tissue, however, were affected by dietary rye inclusion level, indicating that rye supplementation to broiler diets might affect immune competence of the birds.

Cecal MicroRNAome response to Salmonella enterica serovar Enteritidis infection in White Leghorn Layer

Background

Salmonella enterica serovar Enteritidis (SE) is a food-borne pathogen and of great threat to human health through consuming the contaminated poultry products. MicroRNAs (miRNAs) play an important role in different biological activities and have been shown to regulate the innate immunity in the bacterial infection. The objective of this study is to identify miRNAs associated with SE infection in laying chicken cecum.

Results

Average number of reads of three libraries constructed from infected and non-infected chickens was 12,476,156 and 10,866,976, respectively. There were 598 miRNAs including 194 potential novel miRNAs identified in which 37 miRNAs were significantly differentially expressed between infected and non-infected chickens. In total, 2897 unique target genes regulated by differentially expressed miRNAs were predicted, in which, 841 genes were uniquely regulated by up-regulated miRNAs (G1), 636 genes were uniquely regulated by down-regulated miRNAs (G2), and 1420 were co-regulated by both up and down- regulated miRNAs (G3). There were 118, 73 and 178 GO (Gene ontology) BP (Biological process) terms significantly enriched in G1, G2 and G3 groups, respectively. More immune-related GO BP terms than metabolism-related terms were found in G1. Expression of 12 immune-related genes of four differentially expressed miRNAs was detected through qRT-PCR. The regulatory direction of gga-miR-1416-5p, gga-miR-1662, and gga-miR-34a-5p were opposite with the target genes of TLR21, BCL10, TLR1LA, NOTCH2 and THBS1, respectively.

Conclusion

The miRNAs contribute to the response to SE infection at the onset of egg laying through regulating the homeostasis between metabolism and immunity. The gga-miR-125b-5p, gga-miR-34a-5p, gga-miR-1416-5p and gga-miR-1662 could play an important role in SE infection through regulating their target genes. The finding herein will pave the foundation for the studies of microRNA regulation in SE infection in laying hens.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-3413-8) contains supplementary material, which is available to authorized users.

Vaccine-induced Th17 cells are established as resident memory cells in the lung and promote local IgA responses

The ability to mount accelerated and efficient mucosal immune responses is critically important to prevent the establishment of many infections. Secretion of immunoglobulin A (IgA) is a key component in this first line of defense, but the underlying cellular mechanisms are still not completely understood. We have evaluated different routes of immunization and examined the requirements for IgA induction in the airway mucosa. We demonstrate that subcutaneous priming with a recombinant antigen in a T helper (Th)17-inducing adjuvant followed by airway boosting promotes high and sustained levels of IgA in the lungs. This response is associated with germinal center formation in the lung-draining lymph nodes. The lung IgA response is dependent on Th17 cells and absent if interleukin (IL)-17 is depleted or when priming with vaccines inducing only Th1 or Th2 responses. We used intravascular staining to demonstrate that IgA+ B cells and chemokine receptor 6 (CCR6)+Th17 cells are recruited to the lung parenchyma after the airway booster immunization. Once recruited to the lung parenchyma, the Th17 cells transform into resident lymphocytes that persist in the lung tissue for at least 10 weeks. Here, they facilitate the accelerated recruitment of T and B cells resulting in an accelerated IgA recall response to a second airway booster immunization.

TLR4 and TLR21 expression, MIF, IFN-β, MD-2, CD14 activation, and sIgA production in chickens administered with EFAL41 strain challenged with Campylobacter jejuni

The protective effect of Enterococcus faecium EFAL41 on chicken's caecum in relation to the TLR (TLR4 and TLR21) activation and production of luminal IgA challenged with Campylobacter jejuni CCM6191 was assessed. The activation of MIF, IFN-β, MD-2 and CD14 was followed-up after bacterial infection. Day-old chicks (40) were divided into four groups (n = 10): control (C), E. faecium AL41 (EFAL41), C. jejuni (CJ) and combined E. faecium AL41+C. jejuni (EFAL41+CJ). Relative mRNA expression of TLR4, TLR21 and CD14 was upregulated in the probiotic strain and infected (combined) group on day 4 and 7 post infection (p.i.). The caecal relative MD-2 mRNA expression was upregulated on day 4 p.i. in the EFAL41+CJ and CJ groups. MIF and IFN-β reached the highest levels in the combined groups on day 7 p.i. The concentration of the sIgA in intestinal flush was upregulated in EFAL41+CJ group on day 4 p.i. The results demonstrated that E. faecium EFAL41 probiotic strain can modulate the TLRs expression and modify the activation of MIF, IFN-β, MD-2 and CD14 molecules in the chickens caecum challenged with C. jejuni CCM 6191. The counts of EFAL41 were sufficient and high, similarly the counts of enterococci in both, caecum and faeces but without reduction of Campylobacter counts.