show Abstracthide AbstractThe gut microbiome interacts with host physiology and plays important roles in the host organism. Although seasonal changes in gut microbiome have been reported in several species, functional significance of seasonal changes in gut microbiome on host physiology remain unclear. Japanese quail (Coturnix japonica) show rapid and robust seasonal responses and provide excellent model to understand this question. When we examined the effects of changing photoperiod and antibiotics, antibiotics treatment significantly attenuated photoperiodic induction of ovarian development in female quail. Analysis of 16S rRNA revealed significant changes in the composition of cecum microbiome between short day (SD) and long day (LD) conditions. To further examine the effects of seasonal changes in cecum microbiome, we examined the effects of cecum microbiome transplantation. Transplantation of cecum microbiome obtained from female quail kept under LD conditions increased ovarian weight under short day conditions. These results suggest the contribution of seasonal changes in cecum microbiome in the photoperiodic regulation of ovary in female. Our results provide new insights into our understanding of seasonal regulation of reproduction.