Antibody titers against SRBC were increased (Pb0.05) by
feeding diets containing yeast autolysate or black cumin
seed (Table 7). There was also a significant interaction
(Pb0.001) between yeast autolysate and black cumin seed
supplementation. The presence of yeast autolysate or black
cumin seed affected anti SRBC titer, however the groups fed
diets containing black cumin seed had highest anti SRBC
titer. This could be explained by the beneficial effects of supplementation
in maintaining a physiological balance of
immunopotent cells and, therefore providing a healthy environment
for the immune system. Similarly some researchers
observed greater antibody titer in laying hens fed diet containing
2, 3 or 4 g/kg yeast autolysate (Yalçın et al., 2010)
and 1 g/kg yeast (Mohiti-Asli et al., 2007). Higher antibody
responses in broiler breeders fed MOS were also observed
in a study by Shashidhara and Devegowda (2003). Toghyani
et al. (2010) showed that diets containing 2 and 4 g/kg
black seed (Nigella sativa L.) failed to induce any significant
impact on antibody titers against Newcastle and influenza viruses
but increased the weight of lymphoid organs significantly
(Pb0.05) in broilers.