Slow-release capsule for reducing winter scours in sheep – STAGE 1: Proof of Concept
Research has shown that it is potentially feasible to use a small continuous dose of worm antigen to prevent immune scouring in sheep.
| Project start date: | 01 August 2010 |
| Project end date: | 06 June 2013 |
| Publication date: | 25 June 2013 |
| Project status: | Completed |
| Livestock species: | Sheep |
| Relevant regions: | National |
|
Download Report
(0.9 MB)
|
|
Summary
The potential for continuous Trichostrongylus antigen administration to sheep as a means to prevent hypersensitivity scours following infection was investigated. The results of the trial demonstrate continuous administration of parasite antigen leads to a suppression of the eosinophil response in the sheep following parasite challenge. This eosinophil suppression correlated with a significantly higher worm count in the antigen treated group. Despite being challenged with 7000 L3s, neither treated nor untreated sheep developed scours, indicating the development of diarrhoea is a multifactorial process. Although scouring did not occur in sheep in this trial following challenge, the suppression of eosinophils, the main mechanism behind the development of immune mediated scouring in sheep, indicates that the continuous administration of low doses of parasite antigen to sheep has the potential to prevent or reduce hypersensitivity diarrhoea in sheep. This concept may serve as a basis development of a commercial intra-ruminal device to prevent scouring in sheep.
Objectives
The aims of this project were threefold:
1) Demonstrate the feasibility of using small, continuous doses of worm antigen to
prevent hypersensitivity scouring in sheep.
2) Serve as the basis behind further research into the development of a commercial
intra-ruminal device to prevent winter scours in sheep based on this concept.
3) Instigate larger multi-centre research into host-parasite interactions in ruminants
to develop novel technologies to reduce the burden of parasitism in red meat
production
Key findings
The results of the study indicate that it is potentially feasible to use a small continuous dose of worm antigen to prevent immune scouring in sheep as we clearly suppressed the eosinophil response using the antigen treatment. The possible deleterious effects of the resultant higher worm burden requires further investigation. As a proof of concept trial, this study has successfully served as a basis from which further research into the development of a commercial intra-ruminal device can be developed based on this concept to reduce scouring in sheep.
Benefits to industry
Reduction in scours will lead to increased productivity and profitability, and reduce associated animal welfare risks.
Future research
It is recommended that additional research be undertaken in the field, and with sheep more inclined towards scouring, to investigate to what extent the antigen treatment can prevent or reduce diarrhoea. If successful in field conditions, work towards an intra-ruminal device based on this concept would be feasible.
In addition, further research is recommended on the role of eosinophils and intraepithelial lymphocytes in parasite immunology and tolerance. This study demonstrated the immune response associated with parasite infection in sheep can be influenced. By understanding the mechanisms by which the immune response can be modified, improved parasite control measures could be developed.
More information
| Project manager: | Johann Schroder |
| Contact email: | reports@mla.com.au |
| Primary researcher: | University of Adelaide |
