Experimental trials to assess the immune modulatory influence of thyme and ginseng oil on NDV-vaccinated broiler chickens

Abstract

Background: The use of traditional medicine against viral disease in animal production has been practiced worldwide. Herbal extracts possess organic substances would improve chicken body performance. Aim: The current study was designed to evaluate the effect of either thyme or ginseng oil in regard to their immune-modulatory, antiviral, and growth promoter properties. Methods: Two hundred and forty- one -day- old broiler chicks were allocated into eight equal groups as the following: group 1; non-vaccinated and non-treated and group 2; NDV vaccinated and non-treated. Birds of groups 3 and 4 were treated with thyme oil (200mg/L of drinking water for 12 hrs/day) without or with NDV vaccination. Birds of groups 5 and 6 were treated with ginseng oil (200mg/L of drinking water for 12 hrs/day) without or with NDV vaccination. Birds of groups 7 and 8 were treated with a combination of ginseng oil (100mg/L of drinking water) and thyme oil (100mg/L of drinking water) for 12 hrs/day. On the 35th day of life, birds in all the experimental groups were given 0.1 mL of a virulent genotype VIId NDV strain suspension containing 106.3 EID50/mL intramuscularly (IM). Results: Administration of ginseng and thyme oils each alone or simultaneously to birds either vaccinated or non-vaccinated elicited a significant improvement in body performance parameters. Administration of thyme and ginseng each alone or concurrently to vaccinated birds (Gp 4, 6 and 8) induced a higher HI titer of 6, 7.3 and 6.3 log2 at 21 days of age, 6.7, 7.6 and 7 log2, at 28 days of age and 7, 8 and 6.8 log2 at 35 days of age, respectively. Challenge with vNDV genotype VII led to an increase in the NDV-specific HI-Ab titers ten days post-challenge in all the experimental groups. In addition, thyme, ginseng oils or a combination of them improved the protection from mortality in vaccinated birds; 100%, 100% and 90% respectively, compared with 80% protection from mortality in vaccinated-only birds post-NDV challenge. Moreover, NDV-vaccinated birds treated either with thyme; ginseng or their combination showed negative detection of the virus in both tracheal and cloacal swabs and non-vaccinated groups that received oils showed improvement in vNDV shedding in tracheal and cloacal swabs. Conclusion: It could be concluded that administration of thyme and ginseng essential oils to broilers can improve productive performance parameters, stimulate humoral immunity against, and protect from vNDV infection.