EN
Maternal antibodies (matAb) can protect avian embryos and young birds after hatching against vertically transmitted pathogens. In birds, maternal IgY in egg yolk is transferred across the yolk sac through the FcRY receptor to passively immunize chicks. High-affinity binding occurs at pH 6, and does not occur at pH greater than 8.0. This study aimed to evaluate the influence of enrofloxacine, florfenicol, and ceftiofur on maternal IgY concentration in the yolk sac and serum of newly hatched chicks. In this study 184 one-day-old chicks were administered enrofloxacine, florfenicol, or ceftiofur in recommended doses according to the currently recommended treatment schedule. The yolk sac and blood were collected daily from day 1 to day 5 (yolk sac) or 7 (blood) of the experiment. Then, the samples were subjected to radial immunodiffusion investigation. The experiment showed that the concentration of IgY in serum on day 3 after the administration of ceftiofur and florfenicol was higher than that in the control group or the enrofloxacine group. It was also shown that after enrofloxacine treatment the level of IgY was higher in the yolk sac on day 4 of the experiment and lower in serum on day 5 of the experiment compared with the corresponding levels of IgY in the ceftiofur and florfenicol groups. These results suggest that the administration of enrofloxacine, florfenicol, and ceftiofur might influence the efficiency of matAb transfer from the yolk sac to the bloodstream of chicks.