Effects of Ocimum sanctum Leaf on pathology and immune response in chickens experimentally infected with hydropericardium syndrome

The effects of Ocimum sanctum leaf (OSL) supplementation was studied in chickens experimentally infected with HPS virus. Sixty chickens at the age of 14 days were given feed mixed with OSL powder while sixty birds were kept on feed without OSL supplementation. At the age of 21 days, each group was further divided into two subgroups and the birds of one of the subgroups from each group were inoculated with HPS virus infected liver suspension (ID₅₀) subcutaneously. The clinical signs exhibited in OSL supplemented- HPS infected birds were of milder nature as compared to that in the non OSL supplemented- HPS group. The mortality due to HPS infection in non- OSL supplemented group was of twelve birds whereas in OSL supplemented group it was only of seven birds. The characteristic pathological changes in HPS infected birds were hydropericardium, hepatitis, myocarditis accompanied with haemorrhages, oedema in lungs, lymphocytic depletion in lymphoid organs and focal interstitial nephritis. There was a marked reduction in the severity of these gross and microscopic lesions in liver, heart, lungs and kidneys due to OSL supplementation. The lymphoid organs of OSL supplemented HPS infected birds did not reveal any changes. DTH response against DNCB antigen was significantly more pronounced in OSL supplemented groups. It is concluded that OSL supplementation reduced the severity of HPS infection and enhanced the CMI response, suggesting the protective role of OSL powder in limiting the pathogenesis of HPS infection in broiler chickens.