Adult duck fecal microbiota transplantation alleviates short beak and dwarfism syndrome in ducklings by inhibiting Th17 cell differentiation.

Novel goose parvovirus (NGPV) infection in ducklings induces short beak and dwarfism syndrome (SBDS), leading to significant economic losses. Since NGPV predominantly infects ducklings, whether reshaping the intestinal flora of ducklings through fecal microbiota transplantation from adult ducks (FMT-A) can alleviate SBDS is an interesting question. This study aimed to investigate the impact of FMT-A on the susceptibility of ducklings to NGPV infection, to elucidate the potential relationship between gut microbiota and viral pathogenicity. The results showed that ducklings were more susceptible to NGPV than adults, and that adult ducks exhibited higher fecal microbiota richness and diversity. FMT-A treatment attenuated NGPV-induced reductions in body weight, beak and tibia length, and muscle mass. Furthermore, FMT-A alleviated gut dysbiosis and intestinal tissue damage, increased glycogen in the intestinal mucosa, upregulated ZO-1 expression, expanded the epiphyseal region, and reduced osteoclast numbers in the tibia of ducklings. Moreover, FMT-A suppressed the expression of the Th17 cell-specific transcription factor retinoic acid receptor-related orphan receptor γt in the ileum and bone, and decreased the expression levels of pro-inflammatory cytokines in the ileum, bone, and serum. These findings indicate that ducklings are more susceptible to NGPV than adult ducks, with significantly lower diversity and abundance of fecal microbiota. FMT-A can stabilize intestinal flora, mitigate intestinal barrier damage, inhibit Th17 cell differentiation, thereby reducing abnormal bone development, and ultimately alleviate SBDS in ducklings. These findings provide a theoretical basis for developing novel strategies targeting gut microbiota modulation to prevent and control SBDS in ducklings.