Intestinal colonization of different Brachyspira spp. in laying hens

Abstract

BACKGROUND:Avian intestinal spirochetosis (AIS) is caused by spiral-shaped Gram-negative Brachyspira spp. in poultry and is known as a cause of diarrhea, low egg production, and increased occurrence of dirty eggs in layer hens. OBJECTIVES: In this study, the presence of some Brachyspira spp. was investigated in laying hens. METHODS: A total of 100 cloacal swab samples were individually collected from 20 laying hen flocks showing fecal egg staining in northeastern Iran. RESULTS: Using culture and<br><br>morphologic examination, 41 samples (41%) from 20 flocks were positive; however, by using genus-specific PCR, only 37 (37%) samples were confirmed as Brachyspira spp. Using speciesspecific<br><br>primers, single colonization was identified in 18 samples associated with B. pilosicoli (48.6%), while single colonization with B. intermedia was found in only two samples (5.4%).<br><br>Simultaneous colonization by B. intermedia and B. murdochii was<br><br>detected in 3 samples (8.1%). B. pilosicoli was the most prevalent<br><br>species in concurrent colonization in 11 cases (29.7%). Finally, cocolonization<br><br>by B. intermedia and B. innocens was identified in 3<br><br>samples (8.1%). CONCLUSIONS: The results of this study showed<br><br>the colonization of different species of Brachyspira with<br><br>dominance of B. pilosicoli in layer hens.