Immunostimulant Effects of Essential Oils of Peppermint and
Eucalyptus in Chickens
M. H. H. Awaad*, G. A. Abdel-Alim, K. S. S. Sayed,
Kawkab, A. Ahmed1, A. A. Nada2, A. S. Z.
Metwalli and A. N. Alkhalaf3
Department of Poultry Diseases, 1Department
of Pathology, Faculty of Veterinary Medicine, Cairo University, Egypt; 2Animal
Health Research Institute, Dokki, Egypt; 3Department of Veterinary
Medicine, College of Agriculture and Veterinary Medicine, King Saud University,
P. O. Box 1482, Buraydah, Qassim, Saudi Arabia *Corresponding author:
awaad_m_h_h@hotmail.com
Abstract
The immunostimulatory effects of peppermint and
eucalyptus essential oils on cell mediated and/or humoral immunity
in chickens vaccinated against
Newcastle disease (ND) and Avian Influenza (AI) were
investigated. The HI titers against both ND and AI vaccines were
higher in volatile oils treated group as compared to the untreated
control. The protection percentage reached 35% in volatile oils
treated group as compared to 25% in untreated control group and 0%
in unvaccinated negative control group on challenge with velogenic
viscerotropic ND virus. The positive effect of volatile oils on
phagocytic activity of macrophages was significantly (P<0.05)
enhanced in treated birds over untreated ones at 14, 28 and 42 days
of age. Their effect on serum nitric oxide level revealed
significant increase in treated birds versus non-treated ones at 28
and 42 days of age. Lysozyme activity did not show significant
change between treated and non-treated groups. In treated birds,
scoring of histomorphological changes of major immune organs
revealed lymphocytic hyperplasia and activation in Bursa of
Fabricious, thymus, spleen and caecal tonsils with a sum of
activation score reaching 8 versus 0
in untreated birds. It was concluded that
eucalyptus and peppermint oils proved to be able to implement
innate-cell mediated, humoral immune response and have a potent
immunomodulatory effect in chickens.
Key words:
AI vaccine,
Chickens,
Essential oils,
Eucalyptus,
HI test, Immunostimulant, Lysozyme activity,
NDV vaccine, Phagocytic activity,
Peppermint