Test of antibacterial feed additives in a Brachyspira hyodysenteriae infection model

Two, non-antibiotic feed additives (Dys-1 and Trial-D1) developed for prevention and alleviation of clinical symptoms of swine dysentery (SD) were studied in an infection model. The feed of two groups (Dys-1, Trial-D1) contained one of the additives and similarly to the third group (T-2) T-2 toxin (2 mg/kg) as well. After 19 days of intake all of the four groups ('Control' group too which did not consume T-2 toxin and any additives) were inoculated with fresh colon scraping of SD affected pigs via gastric tube, Form, appearance and consistency of faeces following the infection was qualified by a 5-grade (0-4) scoring system. Fisher exact probe demonstrated that frequency of diarrhoea scores depended on treatments. Average live weight and daily weight gain of Dys-1 pigs were found superior to that of the others. Gross pathologiacl lesions of SD were foun d exclusively in pigs that showed the clinical signs of the disease at the time of exsanguination. Data of the present experiment justifies further improvement of Dys-1 and semi-field trials with the upgraded additive. The infection model, with minor alterations, seems suitable for further studies with sd