Broody behavior is regulated by hypothalamic prolactin secretion, which seriously affects egg production in poulty production.  Numerous studies have provided evidence that animal behavior is governed by dynamic bidirectional communication between specific gut bacteria and their host via the brain–gut–microbiome axis.  However, little research focused on how the gut microbiota influence broody behavior in poultry.  In this study, Zhedong white geese in laying and brooding phases were selected.  Ten differentially abundant bacteria in cecum were detected between brooding and laying geese through metagenomic analyses and 16S rRNA sequencing (P<0.05), and Bacteroides fragilis was specifically identified as a key driver species in the brooding geese.  Moverover, the serum metabolites were quantified, and the 313 differentially abundant metabolites were found between the two groups of different physiological geese.  They were primarily enriched in the tryptophan metabolism pathways.  Pearson correlation analyses revealed there was a significant positive correlation between B. fragilis abundance and the context of 11 tryptophan metabolism-related metabolites (such as serotonin, etc.) in broody geese, which hinted that those tryptophan metabolites might be produced or driven by B. fragilis.  Finally, the serum hormone levels were also measured.  We found there was a positive correlation between B. fragilis abundance and content of serotonin.  Besides, prolactin secreted by the pituitary gland was greater in brooding geese than that in laying geese, which was also highly correlated with B. fragilis abundance.  This result implied that B. fragilis could promote the secretion of prolactin by the pituitary gland.  Together, the current study findings provided the information on gut microbiota influencing broody behavior, B. fragilis produced or driven more serum serotonin, and stimulated the pituitary gland to secret more prolactin, which potentially offered a new enlightenment for the intervention of broody behavior in poultry.

The Chinese crested duck is a unique duck breed having a bulbous feather shape on its duck head.  However, the mechanisms involved in its formation and development are unclear.  In the present study, RNA sequencing analysis was performed on the crested tissues of 6 Chinese crested ducks and the scalp tissues of 6 cherry valley ducks (CVs) from 2 developmental stages.  This study identified 261 differentially expressed genes (DEGs), 122 upregulated and 139 downregulated, in the E28 stage and 361 DEGs, 154 upregulated and 207 downregulated in the D42 stage between CC and CV ducks.  The subsequent results of weighted gene co-expression network analysis (WGCNA) revealed that the turquoise and cyan modules were associated with the crest trait in the D42 stage, meanwhile, the green, brown, and pink modules were associated with the crest trait in the E28 stage.  Venn analysis of the DEGs and WGCNA showed that 145 and 45 genes are associated between the D42 and E28 stages, respectively.  The expression of WNT16, BMP2, SLC35F2, SLC6A15, APOBEC2, ABHD6, TNNC2, MYL1, and TNNI2 were verified by real-time quantitative PCR.  This study provides an approach to reveal the molecular mechanisms underlying the crested trait development.

Germplasm resources are essential for the sustainable development of biodiversity and husbandry of local chickens, as well as for the breeding and industry of superior quality chickens. Unfortunately, many local and indigenous chicken breeds are at risk of declining numbers, emphasizing the need to conserve breed resources for endangered chickens. Primordial germ cells (PGCs) are crucial for preserving germplasm resources by inheriting genetic information from parents to offspring and ensuring stability of genetic material between germlines. In this study, PGCs were isolated from chicken embryos' gonads and cultured in FAcs medium without feeder cells. Over a period of approximately 40 days, the cells proliferated to a number of up to 10⁶, establishing various cell lines. Particularly, 18 PGC lines were created from Rugao Yellow Chicken and Shouguang Chicken, with an efficiency ranging from 39.1% to 45%. Furthermore, PGCs that had been cultured for 40 passages exhibited typical PGC characteristics, such as glycogen staining reaction, and expression of pluripotency and reproductive markers. These results confirm that PGCs maintain stem cell properties even after long-term in vitro culture. Additionally, PGCs cryopreserved for up to 120 days remained viable, maintained typical PGC morphologies, and possessed stable cell proliferation ability. Through intravascular injection into chicken embryos, green fluorescent protein (GFP)-PGCs were found in the recipient embryos' gonads and could develop into gametes to produce offspring, indicating that even after extended culture, PGCs retain their migratory and lineage-transmitting capabilities. This research offers valuable insights into the in vitro cultivation and preservation of PGCs of Chinese indigenous chickens. The findings of this study can be applied in transgenic chicken production and the preservation of genetic resources of indigenous chicken breeds.