ABSTRACT
Leaf extract of Psidium guajava were subjected to phytochemical screening and in ovo antiviral assay against Newcastle Disease Virus (NDV). Phytochemical analysis revealed the presence of pharmacologically active and nutritionally relevant compounds. Nine-day-old embryonated chicken eggs were divided into ten groups of fives and received various treatments. Groups 1-6 received 100EID50/0.1ml NDV pre-treated with P. guajava leaf extracts at final concentrations of 250, 200, 100, 50, 25 and 10mg/ml in that order. Controls were included. Embryo survival was observed daily. Allantoic fluid from treated eggs and serum from hatched chicks were collected for spot hemagglutination (HA) and hemagglutination inhibition (HI) tests to detect NDV in the eggs and antibodies against NDV in the hatched chicks respectively. Results showed that embryo survival was higher with higher extract concentrations.. Just as increase in extract concentration was directly proportional to virus death and inversely proportional to production of antibody against NDV in hatched chicks. The current findings have clearly demonstrated that P. guajava leaf extract has nutritional value as well as great antiviral potential against NDV in ovo. In vivo trials are needed to validate the use of the tree in controlling Newcastle disease in chickens.