Abstract

The present study was conducted in order to determine the quality of commercially available Angara disease vaccines. For the experiment, 200 broiler chicks of one day old were reared at National Veterinary Laboratories, Islamabad in isolation units. Chicks were divided into three groups that is, 1, 2, 3 and having 25, 25 and 150 chicks, respectively. Group 1 was used to determine LD₅₀ of the virus in chicks, whereas the chicks of group 2 and 3 were used to assess the safety and potency of the vaccines. The LD₅₀  (lethal dose₅₀) of the virus was determined in 26 days old broiler chickens divided into sub-groups a, b, c, d and e. The LD₅₀ titre of the (10%) viral suspension was prepared from liver extract and determined as 10^-2.4 per ml. During investigation before use, the sterility of the vaccines was carried out by culturing on microbiological   media. All four vaccines were found free from any contamination.  The safety standard of the vaccines was also tested by inoculating in 25 chicks of sub-groups F, G, H, I and J, each contained 5 chicks. The chicks were kept under observation for five days post-vaccination. All four vaccines used in chicks were found safe. During study, the potency of the vaccines was determined by vaccinating 150 chicks of sub-group K, L, M, N and O with dose of 0.2 ml. The vaccinated and non-vaccinated chicks of sub-groups were challenged with viral dose of 2 ml at day 17 post-vaccination to know the protection potency of the vaccines. No any chick showed clinical manifestation of disease up to five days post challenge. On post-mortem examination, lesions of hydropericardium syndrome such as straw colour like fluid was observed around the heart. Other lesions recorded were hydronephrosis and hepatitis. Sera of different groups were checked for demonstration of antibody titration. A higher antibody titre was observed at day 21 as compared to 7 and 14 days post vaccination. Purity of vaccines was also determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Multiple proteins bands were seen however, a band at the position of 18.6 Kda was observed in all four vaccines and positive control as well, which was detected as viral protein. All four vaccines showed similar viral protein profile by SDS-PAGE.

Key words: Quality, antibody, potency, Angara disease, titre.

Abbreviation

 BHIA, Brain heart infusion agar, RCM, reinforcement clostridial medium;BA, blood agar; MA, mycoplasma agar; SA, sabouraud agar; GMT, geometric mean titre.