A rapid yolk-sac serum extraction method for quantifying maternal IgY of individual birds

Maternal immunoglobulin Y (IgY) antibodies in birds are deposited into the egg yolk and are later transferred to the developing embryo via the yolk sac during embryonic development. Quantification of IgY in egg yolk and yolk sac sera is used to assess maternal antibody transfer. Current yolk sac serum extraction methods require large sample volumes, necessitating the pooling of yolk sac samples from several birds. Here, we describe a modified yolk-sac serum extraction protocol that requires a smaller volume and enables individual quantification of IgY, allowing assessment of inter-individual variability in maternal antibody transfer within a flock. The proposed method, while using a reduced sample volume, also maintains antibody levels for downstream immunoassays. While pooled samples provide an overview of the flock's immunological status, analyzing individual antibody levels enables assessment of variability in vertical antibody transfer, which may reflect differences in maternal immune status. • Individual maternal antibody transfer quantification. • Small sample volume input. • Rapid and efficient method for preparing samples compatible with immunoassays.