Gut integrity in piglets – The first line of defense

A healthy functioning gut barrier and an intact mucus layer is crucial to combat potential infections post-weaning.

The gut barrier is the first line of host defence
The gut barrier is one part of the innate immune system, which comprises the first line host defence mechanisms against pathogen exposure. The main component of this barrier is the intestinal epithelium lining which forms the luminal surface to the external environment of both the small and large intestines. The luminal side of the intestinal epithelium is covered by the mucus layer which serves several purposes. It forms a lubricating selective barrier which traps pathogens and unwanted substances and washes them off as the mucus gets replenished. A key component of the mucus layer are the mucins, which are proteins covered in chains of sugar and which stick together to give the mucus its gel-like structure. The mucins are produced primarily by Goblet cells – one of the specialised cell types that make up the intestinal epithelial lining.

The immune system of the newborn piglet is underdeveloped due to missing antibody supply from the placenta, and acquisition of passive immunity through colostrum and milk is therefore crucial for survival. Colostral and maternal antibodies provide the first source of immune protection. However, the maternal supply of antibodies under commercial pig production is withdrawn at weaning, leaving the newly weaned pig in a vulnerable state as the active immune system is not yet developed. A fully functioning innate immunity including having a healthy functioning gut barrier and an intact mucus layer is therefore crucial if the pig is to combat potential infections post-weaning.

In vitro studies demonstrate the potential of SolPreme strains
Using the transepithelial electrical resistance (TEER) assay, a healthy and a compromised gut barrier can be mimicked. In this assay, the amount of fluorescein isothiocyanate tagged sugar molecules (FITC-dextrans) that translocate from the apical side across the cell monolayers can be measured. The greater the amount of translocated FITC-dextrans, the more “leaky” is the cell monolayer. In Figure 1, this assay has been used to demonstrate the potential for the probiotic product SolPreme to support gut barrier integrity. The intestinal epithelial cell monolayers were incubated with or without SolPreme and then exposed or not to the reactive oxygen species (ROS) hydrogen peroxide (H2O2) as a model for oxidative stress. ROS are natural by-products of cellular metabolism. However, excessive ROS can lead to oxidative stress which can cause damage to cells. What we see is that H2O2 increases FITC-dextran-20kDa (FD20) translocation. But when we co-administer SolPreme to the H2O2-exposed cells, we see a prevention of FD20 translocation (Source: Internal).