Abstract

Newcastle disease virus (NDV) strain V₄-UPM was investigated for its viability when coated on different grains offal following exposure to room temperature (RT) (21-27°C) for 8 weeks and using residual infectivity titration at weekly intervals in chick embryos as a measure of viability. The grains (maize, sorghum and millet) used for the study were processed to produce the offal which was dried in the sun before and at RT under a gentle air current after coating with virus. The time duration taken for the infectivity of the virus to drop below the minimum immunizing dose (MID) (log₁₀ EID₅₀/g ≥ 6.0) was compared for virus suspensions containing additive (2% gelatin) and without additive. Results showed that the virus coated onto the carrier foods offal without additive remained stable at ≥ MID value for ≈3 weeks (millet), 3.5 weeks (sorghum) and ≈5 weeks (maize) and with additive for  ≈5.2 weeks (sorghum), 5 weeks (millet) and ≈6 weeks (maize)  at RT. Thus, V₄-UPM was found in this study to be stable even without additive for a minimum of 3 weeks on one of the grains offal, a reasonable time for the food vaccine to reach remote areas of most villages. It is concluded that the waste byproducts of any of these foods could be suitable as carriers for food-based vaccination of rural chickens in Nigeria.

Key words: V4-UPM, grains offal, stability, room temperature, storage.