Fatty acid‐binding protein is essential for molting and male mating in <scp> <i>Dermanyssus gallinae</i> </scp> and confers protection as a vaccine antigen

BACKGROUND: Fatty acid-binding proteins (FABPs) play crucial roles in various physiological processes in arthropods and are considered promising targets for pest control. However, their functions and potential as vaccine candidates against Dermanyssus gallinae, a notorious hematophagous poultry pest, remain unexplored. This study aims to characterize a newly identified FABP in D. gallinae (designated as DgFABP), elucidate its physiological roles, and evaluate its potential as a candidate vaccine antigen. RESULTS: The DgFABP was localized in the testes, synganglion, cuticle, and midgut of male mites. RNA interference (RNAi) silencing of DgFABP significantly increased mortality in adult males (by 13.3%) and male deutonymphs (by 34.7%), while reducing the latter molting rate by 11.6%. Notably, the mating rate of individual males decreased by 60.0%, which consequently led to a significant reduction in the oviposition rate of the female in freely mating assays. Recombinant DgFABP (rDgFABP) induced strong antibody responses in chicks. This immune response resulted in a significant increase in the mortality rates of both male and female deutonymphs. Most importantly, the lowest oviposition rate (35.98 ± 2.13%) was observed when virgin females fed on immunized birds were mated with males who had fed on immunized chicks as deutonymphs. CONCLUSION: DgFABP is critical for the survival, molting, and reproductive success of D. gallinae. The significant reduction in reproductive ability and increased mite mortality following immunization highlights the strong potential of rDgFABP as a novel vaccine candidate for the sustainable control of poultry red mite infestations. © 2026 Society of Chemical Industry.