Abstract
Hydropericardium syndrome (HPS) is common even in the commercial broilers that ale vaccinated using locally prepared HPS virus infected liver homogenate (HPS LH) vaccine In the HI'S LH vaccine production process some of the in process quality control factors mitigate its efficacy I he HPS LH vaccine containing more than 10(4 6) of bird lethal dose 50 (LD50) when injected to 14 days old broilers and 21 days post vaccination given challenge with infection dose (100 units of LD50 of HPS LH) shoved 100 per cent protection Moreover less than 25 doses of the vaccine prepared from one gram of the HPS LH induced 90 pet cent protection in the vaccinated birds Addition of adjuvant such as oil base (Montanide ISA 70) or aluminum hydioxide gel (AHG) in the vaccine showed additive effect on its efficacy The birds vaccinated with montanide based HPS I H vaccine (10(4 6) units of LD50 25 doses/gram) showed 100 percent protection to challenge infection The montanide is more effective adjuvant ant as compared to AHG Infectivity titer (LD50) of LIPS virus infected chicken embryo hepatocyte homogenate (CLHH) was 100 times less (10(2) (5) units) than that of HPS LH Gel based HPS CEHII vaccine (LD50 titer 10(2 5) units) showed poor response in the vaccinated birds (40 per cent protection) as compared to that of gel based LIPS LH vaccine (90 per cent) It is concluded that gel based vaccine prepared from fresh HPS LH is more effective and economical as compared to that of HPS CDHH vaccine