Table 1 Design of the transmission study with the samples/actions and diagnostics/products, as a function of the pigs’ age
Age of the pigs in weeks | Sampling or action (Group) | Frequency (Number of pigs) | Diagnostic method or product |
|---|---|---|---|
3 - 8 | Floor faeces (group A, B, C, D) | Once/week (1 pool/pen; n = 7) | Isolation (ISO 6579 Annex D) |
9 - 15 | Rectal faeces (group A, B, C, D) | Twice/week (individually; n = 56) | Isolation (ISO 6579 Annex D) |
3 - 15 | Blood (group A, B, C, D) | Once/week (n = 56) | ELISA a |
3 - 15 | Feed supplementation (group B) | Ad libitum (n = 15) | Coated calcium-butyrate salt (Globamax Performant,, Sanluc International) |
4 + 7 | Oral vaccination (group A, B) | Twice: primer + boost | 107 - 108 CFU of DIVA vaccine |
(n = 16(A); n = 15(B)) | ‘Salmoporc-∆rfaJ’ | ||
9 | Oral challenge (group A, B, C) | Once; in a separate stable, with replacement 24 h later (2 pigs/pen; n = 12) | 107 CFU of nalidixic acid-resistant Salmonella Typhimurium strain 112910a |
15 | Rectal faeces, Ileum + content, Caecum + content, Ileocaecal Lnn, Tonsils (group A, B, C, D) | At necropsy (n = 56) | Isolation (ISO 6579 Annex D) |