Formulation of novel trehalose flakes for storage and delivery of newcastle disease (strain I-2) vaccine to chickens

Abstract

Newcastle disease (ND) strain I-2 vaccine flakes were formulated by using an amorphous trehalose sugar as a stabilizer and evaluated for long term storage and delivery to chickens. The results showed that the I-2 virus stored in trehalose flakes maintained its infectivity titre at 108.6 EID 50/0.1 mL for 4 weeks at ambient room temperature. The vaccine flakes were stable after storage for 16 weeks while maintaining the infectivity titre of 107.5 EID 50/0.1 mL. The results further indicated that the infectivity titres for ND virus recovered from flakes and liquid vaccine were similar. The findings from the present study showed the vaccine flakes are easily transported and readily released into a fluid phase when mixed with water; they can be administered orally without mixing with feeds and hence suitable for individual or mass vaccination of semi-feral scavenging village chickens. Chickens vaccinated orally with the flakes developed antiviral antibodies and resisted challenge with virulent strain of ND virus. The formulation of trehalose vaccine flakes could be a useful way to store and deliver ND vaccines to village chicken flocks in rural areas, particularly in developing countries if it is optimised.