Prebiotic Driven Increases in IL-17A Do Not Prevent Campylobacter jejuni Colonization of Chickens

© Copyright © 2020 Flaujac Lafontaine, Richards, Connerton, O’Kane, Ghaffar, Cummings, Fish and Connerton. Worldwide Campylobacter jejuni is a leading cause of foodborne disease. Contamination of chicken meat with digesta from C. jejuni-positive birds during slaughter and processing is a key route of transmission to humans through the food chain. Colonization of chickens with C. jejuni elicits host innate immune responses that may be modulated by dietary additives to provide a reduction in the number of campylobacters colonizing the gastrointestinal tract and thereby reduce the likelihood of human exposure to an infectious dose. Here we report the effects of prebiotic galacto-oligosaccharide (GOS) on broiler chickens colonized with C. jejuni when challenged at either an early stage in development at 6 days of age or 20 days old when campylobacters are frequently detected in commercial flocks. GOS-fed birds had increased growth performance, but the levels of C. jejuni colonizing the cecal pouches were unchanged irrespective of the age of challenge. Dietary GOS modulated the immune response to C. jejuni by increasing cytokine IL-17A expression at colonization. Correspondingly, reduced diversity of the cecal microbiota was associated with Campylobacter colonization in GOS-fed birds. In birds challenged at 6 days-old the reduction in microbial diversity was accompanied by an increase in the relative abundance of Escherichia spp. Whilst immuno-modulation of the Th17 pro-inflammatory response did not prevent C. jejuni colonization of the intestinal tract of broiler chickens, the study highlights the potential for combinations of prebiotics, and specific competitors (synbiotics) to engage with the host innate immunity to reduce pathogen burdens

Galacto-Oligosaccharides Modulate the Juvenile Gut Microbiome and Innate Immunity To Improve Broiler Chicken Performance

Copyright © 2020 Richards et al Improvements in growth performance and health are key goals in broiler chicken production. Inclusion of prebiotic galacto-oligosaccharides (GOS) in broiler feed enhanced the growth rate and feed conversion of chickens relative to those obtained with a calorie-matched control diet. Comparison of the cecal microbiota identified key differences in abundances of Lactobacillus spp. Increased levels of Lactobacillus johnsonii in GOS-fed juvenile birds at the expense of Lactobacillus crispatus were linked to improved performance (growth rate and market weight). Investigation of the innate immune responses highlighted increases of ileal and cecal interleukin-17A (IL-17A) gene expression counterposed to a decrease in IL-10. Quantification of the autochthonous Lactobacillus spp. revealed a correlation between bird performance and L. johnsonii abundance. Shifts in the cecal populations of key Lactobacillus spp. of juvenile birds primed intestinal innate immunity without harmful pathogen challenge. IMPORTANCE Improvements in the growth rate of broiler chickens can be achieved through dietary manipulation of the naturally occurring bacterial populations while mitigating the withdrawal of antibiotic growth promoters. Prebiotic galactooligosaccharides (GOS) are manufactured as a by-product of dairy cheese production and can be incorporated into the diets of juvenile chickens to improve their health and performance. This study investigated the key mechanisms behind this progression and pinpointed L. johnsonii as a key species that facilitates the enhancements in growth rate and gut health. The study identified the relationships between the GOS diet, L. johnsonii intestinal populations, and cytokine immune effectors to improve growth

Prebiotic galactooligosaccharide feed modifies the chicken gut microbiota to efficiently clear Salmonella

Chicken meat is contaminated with Salmonella from the gut of infected chickens during slaughter. Eradication of Salmonella from broiler chickens through hygiene measures and/or vaccination is not cost-effective; complementary approaches are required. A mature gut microbiota obstructs Salmonella infection in chickens, and deliberate fortification of colonization resistance through prebiotic feed formulations would benefit public health and poultry production. Prebiotic galactooligosaccharides hastens Salmonella clearance from the gut of infected chickens. To better understand the role of galactooligosaccharides in colonization resistance, broiler chickens were raised on a wheat-soybean meal-based feed, with or without galactooligosaccharides for the first 24 days of life. Chickens were orally challenged with Salmonella enterica serovar Enteritidis at 20 days and the effect of supplementary galactooligosaccharides characterized by profiling Salmonella colonization, gut microbiota, innate immune response, and cecal short-chain fatty acid concentrations. Exposure to dietary galactooligosaccharides shortened the time to clear S. Enteritidis from the ceca. Differential abundance analysis of the cecal microbiota associated Salmonella challenge with a bacterial taxon belonging to the Acidaminococcaceae family (P < 0.005). Increased cecal concentrations of the short-chain fatty acids propionate and valerate were measured in Salmonella-challenged chickens sustained on either control or galactooligosaccharide-supplemented feed relative to mock-challenged controls; but far greater concentrations were detected in chickens fed a galactooligosaccharide-supplemented diet in early life. The abundance of the Acidaminococcaceae taxon exhibited a positive correlation with the cecal concentrations of propionate (ρ = 0.724, P = 0.008) and valerate (ρ = 0.71, P = 0.013). The absence of cecal pro-inflammatory transcriptional responses suggest that the rapid Salmonella clearance observed for the galactooligosaccharide-supplemented diet was not linked to innate immune function. IMPORTANCE: Work presented here identifies bacterial taxa responsible for colonization resistance to Salmonella in broiler chickens. Deliberate cultivation of these taxa with prebiotic galactooligosaccharide has potential as a straight-forward, safe, and cost-effective intervention against Salmonella. We hypothesize that catabolism of galactooligosaccharide and its breakdown products by indigenous microorganisms colonizing the chicken gut produce excess levels of propionate. In the absence of gross inflammation, propionate is inimical to Salmonella and hastens intestinal clearance

In Vitro Evaluation of the Effects of Commercial Prebiotic GOS and FOS Products on Human Colonic Caco–2 Cells

Prebiotic oligosaccharides are widely used as human and animal feed additives for their beneficial effects on the gut microbiota. However, there are limited data to assess the direct effect of such functional foods on the transcriptome of intestinal epithelial cells. The purpose of this study is to describe the differential transcriptomes and cellular pathways of colonic cells directly exposed to galacto-oligosaccharides (GOS) and fructo-oligosaccharides (FOS). We have examined the differential gene expression of polarized Caco&ndash;2 cells treated with GOS or FOS products and their respective mock-treated cells using mRNA sequencing (RNA-seq). A total of 89 significant differentially expressed genes were identified between GOS and mock-treated groups. For FOS treatment, a reduced number of 12 significant genes were observed to be differentially expressed relative to the control group. KEGG and gene ontology functional analysis revealed that genes up-regulated in the presence of GOS were involved in digestion and absorption processes, fatty acids and steroids metabolism, potential antimicrobial proteins, energy-dependent and -independent transmembrane trafficking of solutes and amino acids. Using our data, we have established complementary non-prebiotic modes of action for these frequently used dietary fibers

Nurse- and midwife-led trials in Australia and New Zealand : Scoping review protocol

Background: Research led by nurses or midwives has the potential to successfully address current issues in clinical care. High-quality randomised controlled trials are needed to inform evidence-based practice; however, nursing and midwifery research has commonly been nonexperimental. Two connected scoping reviews of nurse- and midwife-led randomised controlled trials within Australia and New Zealand will be conducted to highlight potential research directions and identify resources for future research. Aim: The purpose of the two reviews is to map the number and types of randomised controlled trials led by nurses or midwives within Australia and New Zealand. Methods: The concept of interest is randomised controlled trials with a lead principal investigator holding nursing or midwifery credentials. The lead principal investigator must report an institutional affiliation in Australia or New Zealand, and the trial must recruit at a minimum of one site in Australia or New Zealand. Searches for academic literature will be conducted using Pubmed, Emcare, and Scopus. Sources for grey literature will include the Australian New Zealand Clinical Trials Registry, and grant outcomes published by the National Health and Medical Research Council, Medical Research Future Fund, and Health Research Council of New Zealand. Data analysis and presentation will be conducted separately for each review. Discussion: These reviews will comprehensively map the experimental research activity of nurses and midwives within Australia and New Zealand and highlight potential research directions. From this, strategies to facilitate high quality nurse- and midwife-led trials can be developed, which are vital for informing evidence-based practice.</p