Intestinal colonization of different Brachyspira spp. in laying hens

Abstract

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