Non-surgical transplantation of Oesophagostomum dentatum to recipient pigs via rectal intubation

Abstract

This experiment was designed to evaluate a new transplantation method, which employs a non-invasive rather than a surgical technique for transplanting Oesophagostomum dentatum worms to recipient pigs. Four groups of pigs were used. Group A (four pigs) served as a donor group, and these pigs were each inoculated with 6000 L 3 of O. dentatum. Groups B, C, and D (five pigs each) served as helminth naive recipient pigs. On Day 28 post inoculation, the donor pigs were slaughtered, and the worms recovered by an agar-gel technique. Wiithin 3–4 h after slaughter of the donor animals, a mean of 357 worms ( ♂/♀ = 1.0) were transferred to each of the sedated recipient pigs via a PVC tube inserted approximately 50 cm up into the rectum and colon descendens. The infection was then monitored by weekly faecal egg counts and by killing the recipient pigs at Week 1 (group B), Week 2 (group C), and Week 3 (group D) post transplantation. The majority of the recovered worms were found in the proximal third of the colon, i.e. the normal predilection site of O. dentatum. The mean worm recovery for groups B and D was 85%, whereas from group C it was only 23%. The faecal egg counts were positive throughout the experiment, although low in group C at the time of slaughter 2 weeks post transplantation. The ♂/♀ ratios changed from an initial 1.0 to 1.5 in group C, whereas there was little or no change in groups B and D. The reason for the deviating results in group C are obscure. This method is less traumatic to animals when compared with surgical transfer techniques, is rapid to perform, and will allow studies on a larger scale.