Research note: Bioaccumulation of β-N-methylamino-L-alanine and 2,4-diaminobutyric acid in chicken eggs

β-N-methylamino-L-alanine (BMAA) and its structural isomer 2,4-diaminobutyric acid (DAB) are non-proteinogenic amino acids known to cause neurotoxicity. Although both compounds have been detected in a range of organisms, their presence in chicken eggs has not been examined. We analyzed egg white and yolk from 30 Swedish eggs obtained from a small-scale producer to assess the bioaccumulation of BMAA and DAB. Both toxins were detected predominantly in egg white. Mean concentrations in egg white were 5.6 ± 3.9 ng g^-1 dry weight (DW) for BMAA and 7.1 ± 4.6 ng g^-1 DW for DAB, compared with 0.7 ± 1.6 ng g^-1 DW and 0.9 ± 0.7 ng g^-1 DW in egg yolk, respectively. The corresponding concentrations of BMAA and DAB on a wet weight (WW) basis were 0.90 ± 0.62 ng g^-1 WW and 1.14 ± 0.74 ng g^-1 WW in egg white, and 0.34 ± 0.77 ng g^-1 WW and 0.43 ± 0.34 ng g^-1 WW in egg yolk, respectively. These findings indicate that chicken eggs from small-scale production systems may represent a previously underrecognized exposure route to BMAA and DAB, highlighting the need for broader surveillance across large-scale commercial egg production systems to confirm whether chicken eggs are a potential source of dietary exposure.