Proteomic profiling of Ascaridia galli reveals sex- and stage-specific protein signatures.

Abstract

Ascaridia galli is one of the most prevalent intestinal nematodes of domesticated chickens and the primary cause of avian ascaridiasis, a globally important disease in poultry production. Infection rates often reach 70-90 % in free-range systems due to its direct life cycle and efficient environmental transmission. Despite its impact, the molecular mechanisms governing A. galli host-parasite interactions remain poorly understood. A. galli belongs to Clade III nematodes, which include several species of major veterinary importance. Comparative genomic studies Clade III-nematodes have revealed expansions in gene families associated with key parasitic traits such as immune modulation, tissue migration, and adaptation to host environments. Proteomics provides a powerful approach for characterizing these processes by identifying proteins essential for development, metabolism, reproduction, and host interaction. However, current knowledge is based almost exclusively on mammalian-infecting species, and no developmental proteome has previously been mapped for A. galli. By profiling protein expression across life stages, this study produces the first proteomic dataset for A. galli. In total, 852 worm proteins were identified. Of these, 452 proteins were shared across female adults, male adults, and larvae, while each group also displayed distinct protein sets. Male worms shared a substantial subset of 327 proteins with females but not larvae, while larvae and females shared 18 proteins. These findings demonstrate that protein expression in parasitic nematodes is strongly sex-specific, with males typically expressing proteins linked to spermatogenesis and motility, and females expressing vitellogenins and lipid-binding proteins.