Date Received: 18-08-2020 / Date Accepted: 14-09-2020
This study was performed to evaluate the influence of a protein rich diet as a provocative factor on producing the clinical disease after infection with three weak β-haemolytic Brachyspira species (B. innocens, B. murdochii and B. intermedia) in fattening pigs.A total of 67 pigs with an average body weight of 15.6 ± 3.1kg were fed a diet containing 50% extracted soybean meal for seven days. The results of the experimental groups (infection with weakly haemolytic Brachyspira species B. innocens, n = 15, B. murdochii, n = 24 and B. intermedia, n = 10) were compared with those of the positive control group (infection with B. hyodysenteriae, n = 15) and the negative control group (n = 3; no inoculation). The results showed that all 15 pigs inoculated with B. hyodysenteriae developed mucohaemorrhagic diarrhea after an incubation period of one to 13 days. In contrast, diarrhea could not be detected in the three groups inoculated with weakly haemolytic Brachyspira species. These groups also showed no significant difference in the average weight gain and feed conversion ratio with no pathological findings typical for dysentery among themselves. It can be therefore concluded that the examined strains of weakly haemolytic Brachyspira species could colonize and proliferate in the mucosa of the large intestine after the experimental infection. Faecal shedding occurred regularly, but no clinical symptoms of swine dysentery could be produced in the experimental pigs.
