The synergestic effect of probiotic and Levamisole on antibody titre of Newcastle disease in presence of E.coli as stress

Abstract

This study was conducted to investigate the effects of probiotic (poultry star®), and immunmodulator (levamisole) in feed additive and in drinking water as synergistic or each one alone on immune response post routine vaccination and challenge with Newcastle disease virus and E.coli, also on means lesion score in (air sac, heart and liver). one hundred Ross broiler chicks were used from 1 day to 35 day old, divided randomly to five groups (20 birds/group), diet and drinking water offered ad libitium, experimental groups treated as follows: Group one: received poultry star® as feed additive in dose (2×1011 CFU/kg) from one day till the end of the experiment. Group two: received levamisole (10µg/kg B.w.) in drinking water from one day till the end of the experiment. Group three: received levamisole (10µg/kg B.W.) in drinking water plus poultry star in feed additive in dose (2×1011 CFU) from one day till the end of the experiment. Group four: control positive positive (vaccinated not treated). Group five: Control negative (not vaccinated not treated). All groups except the control (negative) vaccinated with ND vaccine (La Sota strain) orally in drinking water at (5 and 15) days and vaccinated with IBD vaccine (intermediate strain) at 12 days. The challenge was carried out through intranasal inoculation with virulent ND virus (100LD50, 1×106) at day 20, exposed to intratracheal inoculation with E.coli (3×107 CFU/ml) at day 22. The obtained results referred to the synergistic effect of probiotic and levamisole in group three that enhanced the immunity against Newcastle virus, also less means level of air sac lesion, pericarditis and perihepatitis score as compared with single effect in the groups (first and second) and also compared with control negative and positive groups. NDV and E.coli Challenge caused high morbidity and no mortality in all vaccinated group compared with control negative. Therefore, all the additive materials (probiotic, levamisole) protected the chicks from bacterial infection E.coli. But did not protect the chicks from infection with virulent NDV in spite of that reducing the severity of infection by reduced the viral replication.