In ovo silencing of SERPINA6 using siRNA alters endocrine responses and embryonic growth in broiler chickens

A temporary reduction in developmental progression during critical incubation stages may impair embryonic growth and subsequent chick quality. This study evaluated whether in ovo siRNA-mediated silencing of the SERPINA6 gene is associated with changes in endocrine responses and late-stage embryonic development in broiler chickens. A total of 720 Ross 308 eggs were randomly assigned to six treatments, including a negative control (no injection), a distilled water control, and four siRNA injection groups administered on Days 3, 7, 14, and 17 of incubation. Embryonic growth parameters were assessed at multiple developmental stages. In addition, relative SERPINA6 mRNA expression was quantified using RT-qPCR, and plasma corticosteroid-binding globulin (CBG) and total corticosterone concentrations were measured on Day 18. SERPINA6 expression was significantly downregulated in siRNA-treated groups, with the most pronounced suppression observed following injection on Day 17. This was accompanied by reduced plasma CBG levels and increased total corticosterone concentrations, resulting in an elevated corticosterone/CBG ratio. These endocrine changes were associated with differences in late-stage embryonic growth, including higher embryo weight and increased utilization of yolk and albumen reserves (P ≤ 0.05). The findings suggest that SERPINA6 silencing may be associated with endocrine-related changes during late embryogenesis. However, further studies are required to evaluate post-hatch performance and to clarify the underlying metabolic mechanisms.