Accepted articles-next issues

This study investigated the dynamics of maternal humoral immunity in Hisex laying hens subjected to prolonged Newcastle disease (ND) vaccination by evaluating IgM, IgG, and IgA concentrations in egg yolk and egg white. Hens aged 28, 31, 37, and 61 weeks were examined, and antibody levels were quantified using commercially available ELISA kits at four time points, days 3, 7, 10, and 14, within collection period. IgM responses were most pronounced in younger hens (28 and 31 weeks), which exhibited early peaks (p≤0.05) followed by significant declines (p≤0.05), consistent with the transient nature of primary antibody responses. Older hens (37 and 61 weeks) showed attenuated or delayed IgM activity, and egg‑white IgM declined progressively with age, suggesting reduced early‑phase immune responsiveness. IgG was predominantly yolk‑associated. In 28‑ and 31‑week‑old hens, yolk IgG remained high and stable; egg‑white IgG showed a day‑10 decrease in 31‑week‑old hens (p < 0.001). In 61‑week‑old hens, yolk IgG increased at day 10 (p < 0.01) but decreased by day 14 (p < 0.05). IgA showed early increases but declined sharply by days 10 and 14 in most age groups (p < 0.05). These reductions were most pronounced in older hens, indicating that mucosal immune responses were short‑lived and more susceptible to age‑related decline. Overall, prolonged ND vaccination effectively supported long‑term IgG‑mediated maternal immunity but was less successful in sustaining IgM and IgA levels, particularly in older hens. These findings highlight significant age‑dependent differences in maternal antibody deposition and underscore the importance of optimizing vaccination programs to enhance protection in newly hatched chick.