Intestinal colonization of different Brachyspira spp. in laying hens

BACKGROUND:Avian intestinal spirochetosis (AIS) is causedby spiral-shaped Gram-negative Brachyspira spp. in poultry. It isknown as a cause of diarrhea, low egg production, and increasedoccurrence of dirty eggs in layer hens. OBJECTIVES: In this study,the presence of some Brachyspira spp. was investigated in layinghens. METHODS: A total of 100 cloacal swab samples wereindividually collected from 20 laying hen flocks showing fecal eggstaining in northeast of Iran. RESULTS: Using culture andmorphologic examination, 41 samples (41%) from 20 flocks werepositive; however, by using genus-specific PCR, only 37 (37%)samples were confirmed as Brachyspira spp. Using speciesspecificprimers, single colonization was identified in 18 samplesassociated with B. pilosicoli (48.6%), while single colonizationwith B. intermedia was found in only two samples (5.4%).Simultaneous colonization by B. intermedia and B. murdochii wasdetected in 3 samples (8.1%). B. pilosicoli was the most prevalentspecies in concurrent colonization in 11 cases (29.7%). Finally, cocolonizationby B. intermedia and B. innocens was identified in 3samples (8.1%). CONCLUSIONS: The results of this study showedthe colonization of different species of Brachyspira withdominance of B. pilosicoli in layer hens.