Yeast hydrolysate prevented E. coli -induced increase in piglet intestinal tissue conductance

The world-wide Covid-19 pandemic forced the 71^st annual meeting of the European Federation of Animal Science (EAAP) conference to be held as a virtual congress for the first time in its history. This made some changes into the programme. For example the posters were presented as 3 minutes pre-recorded mini-presentations. One of the posters from Hankkija FFI was on a trial studying pig gut tissue permeability changes with enterotoxigenic E. coli with F4 fimbriae (F4-ETEC).

The enterotoxigenic E. coli with F4 fimbriae (F4 ETEC) is known to increase intestinal permeability in pigs. This process may lead to loss of homeostasis, diarrhoea, and reduced performance. It is well acknowledged that the cell wall of Saccharomyces cerevisiae yeast contains macromolecules that are able bind to the fimbriae of F4-ETEC. Thus these structures may inhibit the ability of F4-ETEC to bind to intestinal mucosa, and to be able to impede the increase in gut permeability.

To study the F4-ETEC effects on intestinal permeability, this experiment applied an ex vivo model in Ussing chambers, where tissue conductance was used as an indirect measure of epithelial permeability. In this model a section of middle jejunum of a piglet was prepared and the mucous tunic was cut and placed into sixteen pairs of Ussing chambers. The tissue cut separates the paired chambers and the apparatus can be used to measure tissue properties like conductance.

To elucidate which components of yeast contribute to the integrity of gut epithelium, a comparison was made between a treatment with Progut® whole yeast hydrolysate and the pathogen F4-ETEC, and a treatment with a yeast cell wall product and the pathogen F4-ETEC. In addition these treatments were compared with a control treatment without the pathogen, and a control with the pathogen F4-ETEC.

RESULTS

As expected, the pathogen F4-ETEC control treatment induced an increasing gut tissue conductance over the 2 hours measurement period, whilst the control treatment without the pathogen showed steady conductance values over the 2 hours. Progut® yeast hydrolysate was able to prevent the F4-ETEC induced increase in the conductance, showing unchanging conductance values during the experiment. This is an interesting indication of potential protection against the negative effects of E. coli on gut tissue.

Further, the treatment with yeast cell wall product showed increasing conductance values, similar to those observed in the control treatment with the pathogen. This indicates that the cell wall product did not have the same inhibitory effect as the whole yeast hydrolysate.

The mechanisms causing the increased gut tissue permeability and conductance are not yet identified. However, this study implied that Progut® has properties that potentially protect the gut tissue against the effects of E.coli with F4 fimbria that the yeast cell wall product does not possess.

Further studies are needed to identify which mechanisms cause the observed changes in conductance induced by E. coli, and to find out how Progut® hydrolysed yeast product counteracts these events.

Reference: Eija Valkonen¹, Hannele Kettunen¹, Shah Hasan¹, Juhani Vuorenmaa¹, Gerhard Breves² (2020) Hydrolysed Saccharomyces cerevisiae -yeast prevented E. coli -induced increase in piglet intestinal tissue conductance in an Ussing chamber ex vivo model. Abstract no 45.11 in: European Federation of Animal Science (EAAP) virtual meeting 1-4 December 2020. ¹Hankkija Oy, FI-05800 Hyvinkää, Finland, ²Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, Bischofsholer Damm 15, 30173 Hannover, Germany