Humoral and mucosal immune responses in challenged chickens vaccinated with Infectious bursal disease vaccine using gums from Cedrela odorata and Khaya senegalensis as delivery agents

ABSTRACT

The emergence of antigenic variants and very virulent strains of infectious bursa disease virus (IBDV) in vaccinated flocks considerably stimulated research in IBDV vaccine administration. The mucoadhesive and immunopotentials of Cedrela odorata and Khaya senegalensis were explored in vaccine delivery against clinical IBDV in broiler chickens. A total of 400 chicks were successfully brooded and raised from day old for commencement of this experiment. The birds were randomly distributed into eight groups with an average of 50 birds per group comprising: Gums-Gumboro Vaccine Ocular (infected) (GGVOC), Gumboro Vaccine alone Ocular (infected) (GVOC), Gums alone Ocular (infected) (GOC), Gums-Gumboro Vaccine Oral (infected) (GGVOR), Gumboro Vaccine alone Oral (infected) (GVOR), Gums alone Oral (infected) (GOR), No-Vaccine-No-Gums (infected) (NVNG/i), and No-Vaccine-No-Gums (not infected) (NVNG). On a weekly basis, 1.5mls of blood were collected from 5 birds and 3 birds euthanized per group for serological analysis and mucosal washings (trachea and intestine) respectively. Data obtained were analyzed and sample to positive ratio calculated. The post 1st vaccination trachea IgG antibody response was moderately higher in the ocular groups than the oral groups. It was also high in the VOC, GVOC, GOC, VOR groups than the GVOR groups. The antibody response (IgG) pre and post 1st vaccination, post 2nd vaccination and post infection from serum, trachea and intestinal washes showed that by week 1 Post 1st vaccination, there was insignificant increase in titer serum response of the gum-vaccine ocular group compared to the vaccine ocular alone while both groups were insignificantly higher than the oral group. Overall, serum titer showed a rapid response with spiked significant response by 48h pi in the gum vaccine groups (especially GVOR), which peaks by day 3 and remains insignificantly higher throughout the day 7 pi compared to vaccine alone groups. In conclusion, use of the mucilage from C. odorata and K. senegalenses in equal proportion has given better enhancement of the response to IBDV vaccination and premise for further investigations for improvement against IBD.

KEYWORDS:

• IBDV
• antibody response
• mucosal washings
• phytogenic adjuvants