Oral inoculation of ultraviolet-irradiated Eimeria species oocysts protects chickens against coccidiosis
Research Abstract
Prevention of coccidiosis is one of the best ways of controlling disease. Therefore, the present study was carried out to
evaluate the protective effect of ultraviolet (UV)-irradiated sporulated oocysts of Eimeria species against coccidiosis in
layer chickens. One hundred forty-four one-day-old layer chicks were randomly divided into 4 groups (n = 36), including
non-immunized/non-challenged negative control group (NC group), non-immunized/challenged control group (NIC
group), non-irradiated sporulated oocyst/challenged group (CA group), and UV-irradiated sporulated oocyst/challenged
(UV group). At the age of 4 days, chickens in groups UV and CA were both orally inoculated with 1.0 × 104 UVirradiated and non-irradiated sporulated oocysts of Eimeria species, respectively. Chickens in groups NIC and NC were
served as positive and negative controls, respectively. Chickens in all groups were orally challenged with 7.5 × 104
sporulated oocysts of Eimeria species except the NC group at the age of 21 days. The results revealed that chicks
receiving UV-irradiated sporulated oocysts had no signs of illness with minimal or no changes in the cecal integrity and
a significantly lower oocyst shedding (OPG) than in the NIC group. Additionally, the cytokine gene expression profiles
were evaluated. Expression levels of IL-2, IL-12, and IFN-γ were significantly higher in the spleen of chicks in the UV
and CA groups than in the NC group post-challenge. As expected, treatment with irradiated oocysts resulted in a
significant reduction in oocyst shedding and maintenance of cecal mucosal integrity. Furthermore, the body weight
was higher in chickens inoculated with UV-irradiated oocysts than their non-irradiated counterparts. In conclusion,
our results demonstrate that inoculation with UV-irradiated sporulated oocysts of Eimeria species can produce a substantial reduction in infection symptoms.
Research Keywords