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.新型鹅细小病毒（Novel goose parvovirus, NGPV）感染雏鸭可诱发短喙矮小综合征（Short beak and dwarfism syndrome, SBDS），造成显著的经济损失。鉴于NGPV主要感染雏鸭，通过成年鸭粪便菌群移植（Fecal microbiota transplantation from adult ducks, FMT-A）重塑雏鸭肠道菌群，能否缓解SBDS是一个颇具研究价值的科学问题。本研究旨在探讨FMT-A对雏鸭感染NGPV易感性的影响，阐明肠道菌群与病毒致病性之间的潜在关联。研究结果显示，雏鸭相较于成年鸭对NGPV更易感，且成年鸭的粪便菌群丰富度与多样性更高。FMT-A干预可减轻NGPV诱导的体重、喙长、胫骨长度及肌肉量下降。此外，FMT-A可缓解肠道菌群失调与肠道组织损伤，提升肠黏膜糖原含量，上调紧密连接蛋白ZO-1的表达，扩大胫骨骨骺区域，并减少雏鸭胫骨中的破骨细胞数量。进一步研究发现，FMT-A可抑制回肠与骨髓中Th17细胞（Th17 cell）特异性转录因子视黄酸受体相关孤儿受体γt（Retinoic acid receptor-related orphan receptor γt）的表达，降低回肠、骨髓及血清中促炎细胞因子的表达水平。上述结果表明，雏鸭相较于成年鸭对NGPV更易感，其粪便菌群多样性与丰度显著更低。FMT-A可稳定肠道菌群结构，减轻肠道屏障损伤，抑制Th17细胞分化，进而改善骨骼发育异常，最终缓解雏鸭的SBDS。本研究为开发靶向调控肠道菌群的新型策略以防控雏鸭SBDS提供了理论依据。