Effect of Ethanol Bark Extract of Mahogany (Sweitenia macrophylla) on Viral Shedding in Cockerels Experimentally Infected with Newcastle Disease Virus Kudu 113 Strain

Abstract

Newcastle disease (ND) is a viral disease that affects both domestic and wild birds. Despite routine vaccination, outbreaks are frequently reported in the field. Studies have indicated that traditional medicinal plants provide rich sources of antiviral agents. Effect of ethanol bark extract of Mahogany (Sweitenia macrophylla) on ND virus shedding in cockerels experimentally infected with NDV Kudu 113 velogenic strain was determined in this study. Phytochemical analysis revealed that the extract contained some antiviral components and LD₅₀ determination indicated that it is safe for consumption at the highest dose given (5500mg/kg body weight). Day old commercial cockerels (150 in number) were obtained and divided into five groups namely; A, B, C, D and E. Group A served as negative control where the birds were given normal feed and water, group B (positive control) were given only the extract, group C were only challenged with velogenic NDV, group D were given the extract after challenge with the virus, and group E were given the extract before challenge. Haemagglutination assay was carried out before experimental infection in groups C, D and E to check antibody titer of NDV. Result revealed that all the groups had unprotective titers. Real-time polymerase chain reaction was carried out to quantify ND viral shedding. The result in copies/ml was highest in group C at day 3 followed by day 5 then day 7 and lowest at day 1. Group D was second in viral shedding; highest at day 3, followed by day 1, day 5 and lowest at day 7. Group E was the lowest in viral shedding where the viral shedding was highest at day 1, followed by day 3, then day 5 and lowest at day 7. Using repeated measure ANOVA within groups C, D and E, difference in viral shedding was statistically significant with P<0.05. It was concluded that ethanol bark extract of Mahogany (Sweitenia macrophylla) has the potential of reducing Newcastle disease viral shedding in chickens when administered as both prophylactic and treatment agent with lowest shedding when given as prophylaxis. It is recommended that ethanol bark extract of Mahogany (Sweitenia macrophylla) should be considered as an alternative to symptomatic therapy done in the management of Newcastle disease.