Effects on plasma pepsinogen, gastrin and pancreatic polypeptide of ostertagia spp. transferred directly into the abomasum of sheep

Abstract

Ostertagia spp. obtained at slaughter from the abomasa. of previously infected sheep and transferred via cannulae into the abomasa of previously worm-free sheep produced severe effects. This was shown with populations of mainly adult parasites given to three sheep and also when mixed populations of 4th stage larvae and adults were given to three other sheep. Although more severe effects were produced when both larval and adult worms were transferred, there were clearly effects when isolates composed predominantly of adults were transferred. Sheep of each group had reductions in food intake and elevations in plasma pepsinogen and gastrin within 24 h of transfer of the parasites. Further increase in plasma pepsinogen and gastrin occurred when abomasal pH rose 5–7 days after infection. Plasma pancreatic polypeptide varied but showed a general tendency to be markedly lower after infection. Ostertagia spp. eggs were detected in the faeces of infected sheep 48 h after transfer. The proportions of adults and inhibited larvae recovered from the abomasa were similar to those in the donor sheep, showing that inhibition, or arrested development of larvae, continued after their transfer to worm free sheep.