Table 1.

Protection efficacy in different groups of chickens against vvIBDV challenge.

Sl. No	Groups	a Mortality	b B/B Ratio	c Bursal Lesion Score	d Protection Percentage
1	Unvaccinated unchallenged	-	0.67 ± 0.28	0 ± 0	-
2	Unvaccinated challenged	10/10 (100%)	0.24 ±0.09	4.6 ± 0.2	0/10 (0%)
3	Live IBDV vaccine	0/10 (0%)	0.48 ± 0.01	2.2 ± 0.2	10/10 (100%)
4	Inactivated IBDV killed vaccine	1/10 (10%)	0.43 ± 0.02	2.8 ± 0.2	9/10 (90%)
5	rNDV F/VP2	0/10 (0%)	0.54 ±0.02	2.0 ± 0.2	10/10 (100%)

^a Mortality was recorded during 10 days period after virus challenge and presented as number of dead chickens/total number of chickens in each group and percentage in parenthesis. ^b Bursa/Body weight ratios was calculated by bursal weight divided by body weight × 100 and presented as the mean ± standard deviation from each group. ^c Bursal lesion score was measured from 0 to 4 based on the increasing severity of bursal lesions; (0) no lesions, (1) mild scattered cell depletion in a few follicles, (2) moderate with 1/3–1/2 of the follicles atrophied or with depleted cells, (3) diffuse with atrophy in all follicles, (4) acute inflammation and necrosis typical of IBD and expressed as the mean ± standard deviation from each group. ^d Protection percentage was determined as the number of protected chickens/total number of chickens in a group ×100.