Commensal microbiome effects on mucosal immune system development in the ruminant gastrointestinal tract

Immunometabolism and the Kinome Peptide Array: A New Perspective and Tool for the Study of Gut Health

Immunometabolism is a relatively new research perspective, focusing on both metabolism and immunology and the cross-talk between these biological processes. Immunometabolism can be considered from two perspectives; 1) the role that immune cells play in organ metabolism and metabolic disease, and 2) the metabolic processes that occur within immune cells and how they affect overall immunity. The gut may be the prototypical organ of immunometabolism. The gut is the site of nutrient absorption and is a major, if not the major, immune organ. We also describe the integration of kinomics and the species-specific peptide array to the study of the gut. This unique immunometabolic tool combined with the unique immunometabolic nature of the gut provides significant research potential to many animal health applications.

Late Enteral Feedings Are Associated with Intestinal Inflammation and Adverse Neonatal Outcomes

BACKGROUND

Morbidities of impaired immunity and dysregulated inflammation are common in preterm infants. Postnatal Intestinal development plays a critical role in the maturation of the immune system and is, in part, driven by exposure to an enteral diet.

OBJECTIVE

The aim of this study was to evaluate the influence of the timing of the first enteral feeding on intestinal inflammation and risk of disease.

METHODS

130 infants <33 weeks' gestation were studied. Maternal and infant data were abstracted from the medical record. Single and multiplex ELISA assays quantified cytokines from fecal and serum samples at two weeks postnatal age.

RESULTS

A delay in enteral feedings after the third postnatal day is associated with a 4.5 (95% CI 1.8-11.5, p=0.002) fold increase in chronic lung disease, 2.9 (1.1-7.8, p=0.03) fold increase in retinopathy of prematurity, and 3.4 (1.2-9.8, p=0.02) fold increase in multiple comorbidities compared to infants fed on or before the third day. Additionally, a delay in the initiation of feedings is associated with increased fecal IL-8 levels and a decreased IL-10:IL-8 ratio.

CONCLUSIONS

A delay in enteral feeding is associated with intestinal inflammation and increased risks of morbidities. To improve neonatal outcomes, early nutritional practices need to be reevaluated.

PI3K/AKT/PTEN pathway as a target for Crohn's disease therapy (Review)

The pathogenesis of inflammatory bowel disease (IBD), including Crohn's disease, is a subject of increasing interest. Loss-of-function mutations in nucleotide-binding oligomerization domain-containing protein 2 (NOD2) are strong genetic factors linked to Crohn's disease, which eventually leads to an excessive mucosal inflammatory response directed against components of normal gut microbiota. Reactive oxygen species (ROS) play an important role in inflammation processes, as well as in transduction of signals from receptors for several cytokines, such as tumor necrosis factor α (TNFα). ROS activate nuclear factor-κB (NF-κB) via IκB kinase (IKK) through the PI3K/AKT/PTEN pathway. Therefore, this pathway is recognized to play a key role in Crohn's disease. Loss of function has been demonstrated to occur as an early event in a wide variety of diseases. Given this prevalent involvement in a number of diseases, the molecular development that modulates this pathway has been the subject of several studies. In addition, it has been the focus of extensive research and drug discovery activities. A better understanding of the molecular assemblies may reveal novel targets for the therapeutic development against Crohn's disease.

Altered egos: antibiotic effects on food animal microbiomes

The human food chain begins with upwards of 1,000 species of bacteria that inhabit the intestinal tracts of poultry and livestock. These intestinal denizens are responsible for the health and safety of a major protein source for humans. The use of antibiotics to treat animal diseases was followed by the surprising discovery that antibiotics enhanced food animal growth, and both led to six decades of antibiotic use that has shaped food animal management practices. Perhaps the greatest impact of antibiotic feeding in food animals has been as a selective force in the evolution of their intestinal bacteria, particularly by increasing the prevalence and diversity of antibiotic resistance genes. Future antibiotic use will likely be limited to prudent applications in both human and veterinary medicine. Improved knowledge of antibiotic effects, particularly of growth-promoting antibiotics, will help overcome the challenges of managing animal health and food safety.

Broiler lines divergently selected for digestive efficiency also differ in their susceptibility to colibacillosis

Increasing feed efficiency of broiler chickens by selective breeding could lead to decreased feed cost and reduced environmental impact of poultry production. At INRA, two broiler chicken lines (D+/D-) were divergently selected for their digestive efficiency. Strong differences were shown between both lines for the anatomy and histology of the digestive tract, and for the intestinal microbiota composition. In the present study, we investigated whether this selection also had an effect on susceptibility to colibacillosis, which is one of the main causes of economic losses in poultry production. The broiler lines D+/D- were challenged with an avian pathogenic Escherichia coli strain. A first experiment was conducted to assess the 50% lethal dose by subcutaneous infection of hatchlings, whereas a second experiment reproduced colibacillosis by infecting air sacs of 23-day-old chicks. The 50% lethal dose was very low for both lines. However, the line with the higher digestive efficiency (D+) was the less susceptible to colibacillosis. This result is interesting for selection purposes and opens the way to integrative genetic studies of the interactions between digestion efficiency and resistance to colibacillosis.

Overfeeding and genetics affect the composition of intestinal microbiota in Anas platyrhynchos (Pekin) and Cairina moschata (Muscovy) ducks

To investigate the effect of overfeeding on the ileal and cecal microbiota of two genotypes of ducks (Pekin and Muscovy), high-throughput 16S rRNA gene-based pyrosequencing was used. The ducks were overfed for 12 days with 58% maize flour and 42% maize grain. Samples were collected before the overfeeding period (at 12 weeks), at 13 weeks, at 14 weeks, and 3 h after feeding. In parallel, ducks fed ad libitum were killed at the same ages. Whatever the digestive segment, the genotype, and the level of intake, Firmicutes and Bacteroidetes are the dominant phyla in the bacterial community of ducks (at least 80%). Before overfeeding, ileal samples were dominated by Bacilli, Clostridia, and Bacteroidia classes (≥ 70%), and cecal samples, by Bacteroidia and Clostridia classes (around 90%) in both Pekin and Muscovy ducks. The richness and diversity decreased in the ileum and increased in the ceca after overfeeding. Overfeeding triggers major changes in the ileum, whereas the ceca are less affected. Overfeeding increased the relative abundance of Clostridiaceae, Lactobacillaceae, Streptococcaceae, and Enterococcaceae families in the ileum, whereas genotype affects particularly three families: Lachnospiraceae, Bacteroidaceae, and Desulfovibrionaceae in the ceca.

Appraisal of microbial evolution to commensalism and pathogenicity in humans

The human body is host to a number of microbes occurring in various forms of host-microbe associations, such as commensals, mutualists, pathogens and opportunistic symbionts. While this association with microbes in certain cases is beneficial to the host, in many other cases it seems to offer no evident benefit or motive. The emergence and re-emergence of newer varieties of infectious diseases with causative agents being strains that were once living in the human system makes it necessary to study the environment and the dynamics under which this host microbe relationship thrives. The present discussion examines this interaction while tracing the origins of this association, and attempts to hypothesize a possible framework of selective pressures that could have lead microbes to inhabit mammalian host systems.