Molecular detection of coronavirus causing infectious bronchitis in laying hens with cystic oviduct and quantitative and qualitative reduction of egg production

In this study, the contribution of IB coronavirus in egg quantitative and qualitative reduction syndrome was investigated.

nine laying hen flocks attected to egg quantitative and qualitative reduction syndrom and 10 laying farms with a healthy appearance were sampled. In addition, 6 farms with cystic oviduct were sampled in laying flocks, in Isfahan province. After extracting the genome, a fragment of 1200 bp of coronavirus S1 gene was amplified for identification of IB.

Out of 9 laying farms with quantitative and qualitative egg reduction syndrome and 10 apparently healthy farms, respectively 7 and 4 farms (78 and 40%) were infected with IB coronavirus based at least one positive sample. Out of 59 samples from farms with egg quantitative and qualitative reduction syndrome, 32 samples (54.2%) and out of 66 samples taken from apparently healthy farms, 7 samples (10.6%) were evaluated positive for IB coronavirus. In this study, all 6 farms with cystic oviduct had at least one positive sample for IB coronavirus and 31 samples out of 41 samples (73.17%) infected with IB coronavirus.

IB coronavirus has a high share in the syndrome of quantitative and qualitative reduction of egg production in laying hens, but not all cases can be attributed to this virus and other infectious and non-infectious factors should be monitored. Due to the high frequency of this virus in cystic oviduct, it is necessary to identify the viral types that induce this disorder and to develop an appropriate control program.