Hannover Veterinary High School, Germany 2004

Progut^TM and the intestinal barriers of pigs (Breves, G. 2004. Veterinary High School, Hannover).

Objective

The aim of the research was to test the effect of Progut^TM on gut physiology of piglet under E.coli (F4) challenge by measuring tissue conductance (Gt) and short circuit current (Isc) in Ussing chamber system. Bio-mos was used as positive control.

Materials and Methods

The small intestine was removed immediately after slaughtering a weaned piglet. A section of the middle jejenum was repeatedly washed with ice-cold physiological common salt solution. The mucous tunic was mechanically separated (stripped) from muscular coat and serous coat. The stripped epithelium was subsequently placed into Ussing chambers (determ. diameter) for 30 mins. It was pre-incubated with Krebs-Ringer solution (pH 7.4). The chambers were subsequently divided according to the follwing protocol and processed:

Chamber 1 to 4 Control

Chamber 5 to 8 + E.coli (F4) mucosal

Chamber 9 to 12 + E.coli (F4) + 30mg/10ml Progut^TM mucosal

Chamber 13 to 16 + E.coli (F4) + 30mg/10ml Bio-Mos mucosal

During the following two-hour incubation, the usual electrophysical parameters, tissue conductance and short circuit current, were continuously registered and recorded. For graphic demonstration of the time dependant progression of short circuit current and tissue conductance, the sigle values belonging together in each group were presented as means and standard deviations.

Results

Generally gut tissue conductance (Gt) decreases during E.coli and other intestinal infections which in turn leads to increased water flow to the gut (diarrhoea) was also seen in the experiment. While the conductance in the control group remained the same at the time (see pictre 1 below), only by adding E.coli lead to a continuous increase in conductance (see picture 2 below). The same thing happened in cultures with Bio-Mos and E.coli (see picture 3 below). In the cultures with Progut^TM and E.coli, the conductance remained unhanged as in the control test (see picture 4 below). This indicates that Progut^TM was capable of protecting the gut tissue from an E.coli infection.

PICTURE 1. GUT TISSUE CONDUCTANCE (GT MS/CM²), CONTROL WITH NO ADDITIVES; +/- STANDARD DEVIATION

PICTURE 2. GUT TISSUE CONDUCTANCE (GT MS/CM²), CONTROL WITH E.COLI; MEAN +/- STANDARD DEVIATION

PICTURE 3. GUT TISSUE CONDUCTANCE (GT MS/CM²), BIO-MOS WITH E.COLI; MEAN +/- STANDARD DEVIATION

PICTURE 4. GUT TISSUE CONDUCTANCE (GT MS/CM²), PROGUT^TM WITH E.COLI; MEAN +/- STANDARD DEVIATION

Short circuit currents were measured as an indicator of electrogenic ion current. In the control groups and after adding E.coli, the short circuit currents stayed virtually constant during the test with average ranges between 1.5 and 2.0 μEq/cm²/h. The values in this range comply with present findings for this intestine section of pigs and are to be considered as physiological. Adding Progut^TM and E.coli lead to a stimulation of short circuit current in a few minutes having a virtually constant average value of 2.5 μEq/cm²/h in the long run. The stimulation of the current can be under the chosen test conditions interpreted as a result of anion secretion or cation absorption. The reason for this stimulation remains unclear and requires further investigation. In the case of Bio-Mos, a time delayed adjustment of a constant short circuit current was registered.

Conclusions

- During the two-hour incubation conductivity between 18 and 35 mS/cm² was measured in all of the experimental chambers. These values are considered to be as normal under the given test consitions.

-There were noticeable differences between the single groups in time dependant course. While the conductance in the control group remained the same, adding only E.coli or Bio-Mos and E.coli lead to a continuous increase in the conductance.

-In cultures with Progut^TM and E.coli the conductance renmained unchanged indicating the capability of Progut^TM to protect the gut tissue from an E.coli infection.

Reference:

Bericht zum Verschusvorhaben Progut^TM und die intestinale Barriere beim Schwein. Brewes, G. 2004. Tierärtzliche Hochschule Hannover.