Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Protective Efficacy of Experimentally Prepared Fowl Typhoid Vaccines

Ferdousi Begum
Department of Microbiology and Hygiene, Bangladesh Agricultural University, Mymensingh-2202.

K. A. Choudhury
Department of Microbiology and Hygiene, Bangladesh Agricultural University, Mymensingh-2202.

M. S. R. Khan
Department of Microbiology and Hygiene, Bangladesh Agricultural University, Mymensingh-2202.

M. M. Rahman
Department of Microbiology and Hygiene, Bangladesh Agricultural University, Mymensingh-2202.

Abstract/ Executive Summary:

Three types of fowl typhoid vaccines such as formalin killed, heat inactivated and live attenuated vaccines were experimentally prepared with a selected field isolate of Salmonella gallinarum to immunize chickens against fowl typhoid. Protective efficacy of the vaccines were measured through virulent challenge at 16 days of second vaccination. It was observed that 10%, 60% and 80% of chickens vaccinated with formalin killed, heal inactivated and live attenuated vaccines respectively survived challenge infection. Among the three types of vaccines used in the present experiment, live attenuated fowl typhoid vaccine was found to be more protective.

Keywords: Protective, Efficacy, Fowl Typhoid, Vaccines

Location: Bangladesh Agricultural University (BAU) Poultry Farm.

Start Date:

End Date:

Program Area: Pest Management

Commodity: Diseases

Objectives:

The present study was concerned with the protective efficacy of three types of experimental vaccines prepared with a local isolate of S. gallinarum.

Methodology:

White leghorn (WLH) chickens of four months of age and not vaccinated against fowl typhoid were obtained from the Bangladesh Agricultural University (BAU) poultry farm. The birds were observed for one month and the apparently healthier birds were selected for experimental use. S gallinarum was isolated from infected birds of Government Central Poultry Farm, Mirpur, Dhaka. Five randomly selected virulent field isolates of S. gallinarum were used to select vaccine and challenge isolate. Prior to the study of pathogenicity test, the bacteria was inoculated in Blood agar (BA) media for three consecutive passages. A single isolated colony of each isolate from third passage was inoculated in 9-10 days old chicken embryos through allantoic sac route for three consecutive passages. An amount of 0.5 ml of allantoic fluid collected from third passages was inoculated in the chicken intramuscularly. Three such consecutive passages were also made to increase the virulence of the organism. The organism so passaged was isolated from chicken and inoculated into the tubes of 5 ml nutrient broth and incubated at 37°C for 18-24 hours to be used as inoculum in pathogenicity test. Five chickens were used to study the pathogenicity of the organism for each selected isolate. Two ml of both culture containing 108 bacteria in 0.5 ml as suggested by Sifva et 01. (1981) was inoculated intramascularly at the thigh muscle of each of the chickens and observed for seven days. The isolate which produced infection and caused subsequent death in maximum number of birds within five days was selected as vaccine and challenge isolate. Three types namely (a) formalin killed (F-K) (b) heat inactivated (HI) and (c) live attenuated (LA) vaccines were prepared with the focal field isolate of S. gallinatum FK vaccine was prepared the procedure. HI vaccine was prepared by heat treatment of the cultured organism (60°C for 3D minutes in whatbath). The vaccines were stored in a refrigerator at 4-8°C. LA vaccine was prepared following the procedure described. Bacteriological sterility, purity and safety tests of the experimental vaccines were conducted as per the method. Challenge dose was prepared following the procedure with sliqht modifications. From the stock culture, the bacteria was grown in BA plates and incubated at 37°C for 24 hours. A single medium size colony from BA plate was then transferred to 5 ml selenite broth and incubated for 16 hours at 37°C. Then the culture was inoculated in tryptose phosphate broth and incubated at 37°C for 48 hours. The culture was then centrifuged at 5000 rpm for 20 minutes and the sediment was collected immediately before challenge infection. The bacterial cells were suspended in physiological saline solution to make 10⁴ bacteria in 01 ml of phosphate buffer saline solution (lPBS). A total of 45 WLH chickens of either sex aged four months old were used in this experiment. The birds were grouped as 'A' and B' and identified individually by leg band. Group 'A' consisting of 30 birds used for immunization and the birds belonging to group 'B' of birds served as unvaccinated control throughout the experiment. Birds of 'A' was subdivided into 'A¹', 'A²' and 'A³' each consisting 10 birds and were inoculated with two doses of FK, HI and LA vaccine respectively at an interval of 14 days. On each occasion, the birds were administered at the rate of I ml of respective vaccine. The immunized birds were housed separately. Vaccinated and control birds were subjected to challenge exposure at the 16th days of second vaccination by intramuscular inoculation in the thigh muscle. An individual challenge dose of 2 ml contained 6 x 10³ to 8 x 10³ CFU of S. gallinarum. Prior to challenge, each vaccinated bird was identified by leg band. In each case, 5 unvaccinated control birds were also inoculated with the same challenge dose All birds were observed daily for two weeks and the result were recorded. From each group, the birds were necropsed as soon as they were found dead. Swabs taken from ovary, intestine, cloaca and faeces were streaked on to BA plates where S gallinorum were confirmed by standard bacteriological procedure. The effect of vaccination with FK, HI and LA vaccines were determined by applying analysis of variance (ANOVA).

Source of Information: Bangladesh Vet. J. 24-26 (1-4)'90-- 93' ISSN 0030-9915

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

Three types of vaccines against fowl typhoid were prepared experimentally to immunize chickens against fowl typhoid. It was revealed from the ANOVA that LA vaccine was superior to two other vaccines in respect of protection capacity against challenge exposure although minor symptoms of infection developed in LA vaccinated group of chickens. The stimulation of a higher protection capacity by LA vaccine may be due to better immunogenic potency of vaccine. Formalin and heat treatment of vaccine might have caused partial loss of their immunogenic potency during preparation.

Knowledge Management: Journal