Neurogenic inflammation in the upper digestive tract of the mule duck: effect of a chemical algogen and force-feeding

1. The objectives were to quantify the presence of neurogenic inflammation in 4 regions of the upper digestive tract of anaesthetised ducks (post-pharynx, pseudo-crop, transition between the pseudo-crop and the proventriculus, and proventriculus) after application of HCl stimulation of up to 4 M in the pseudo-crop.

2. The second objective was to quantify the presence of neurogenic inflammation in the same digestive tract regions as mentioned above during 4 feeding periods of foie gras production (rearing, preparation to force-feeding, and second and last meals of the force-feeding period).

3. Extravasation increased above a HCl stimulation threshold of 2 M. Furthermore, more extravasation was observed in the proventriculus compared to the other regions (P < 0·001).

4. Highest extravasation responses were observed in the proventriculus and the pseudo-crop at the end of the preparation period, and in the proventriculus after the second forced meal, compared with the rearing period (P < 0·01), with a return to rearing level at the end of force-feeding.

5. Such a kinetic could be indicative of a relative mildness of the irritant components associated with this feeding practice.