The issue of food safety concerning lamb following the BSE epidemic has raised similar concerns as those in relation to beef. The confirmation of transmissibility of BSE to other species, including man, by the oral route has raised suspicions that the sheep flock may also be infected.
<p> Experiments have already demonstrated that sheep are susceptible to BSE when administered by the oral route but to date no evidence for natural infection in the field has been found. It has been suggested that scrapie infection, which is not transmissible to other species, may be masking BSE infection in the sheep flock since the two diseases are not distinguishable by clinical signs alone.
<p>Anil et al. (2001) demonstrated the presence of neural tissue emboli in the jugular venous return of sheep following stunning with captive bolt gun devices. Both cartridge operated and pneumatic type captive bolt guns are widely used in the pre-slaughter stunning of sheep in the United Kingdom. This project aims to determine the prevalence of neural tissue emboli in sheep following stunning by current methods.
<p>In addition to determining the prevalence of neural embolism this project also aims to demonstrate whether the emboli could contaminate the carcass after passing through the lungs into the arterial circulation. Demonstration of embolic material in the aorta would substantiate claims that neural tissue emboli pose a risk for contamination of the entire carcass.
The project plan requires that 200 animals will be sampled of which half of each will be stunned using the pneumatic and conventional cartridge operated captive bolt guns respectively. All samples will be collected from anaesthetised sheep at the University of Bristol Veterinary School at Langford.
<p>The prevalence of neural embolism will then be determined. In order to demonstrate whether the emboli could contaminate the carcass after passing through the lungs into the arterial circulation, blood will be sampled directly from the aorta or left ventricle of the heart after first injecting a suitable brain tissue suspension into the jugular venous supply of the same test animal. <P>
The final report, "<a href="http://www.foodbase.org.uk/results.php?f_report_id=66" target="_new">Prevalence of CNS Embolism and Determination of Potential for Visceral Dissemination at Stunning and Slaughter in Sheep</a>" is available at Foodbase, an open access repository of the <acronym title="Food Standards Agency">FSA</acronym>.
<p> Find more about this project and other FSA food safety-related projects at the <a href="http://www.food.gov.uk/science/research/" target="_blank">Food Standards Agency Research webpage</a>.