To identify the dominant genes controlling follicular maturation, ovulation and regression for pigeon, we used RNA-seq to explore the gene expression profiles of pre- and post-ovulatory follicles of pigeon. We obtained total of 4.73 million (96% of the raw data) high-quality clean reads, which could be aligned with 20 282 genes. Gene expression profile analysis identified 1461 differentially expressed genes (DEGs) between the pre- (P4) and post-ovulatory follicles (P5). Of these, 843 genes were upregulated, and 618 genes were down-regulated. Furthermore, many DEGs were significantly enriched in some pathways closely related to follicle maturation, ovulation and regression, such as ECM–receptor interaction, vascular smooth muscle contraction, progesterone-mediated oocyte maturation, phagosome. Importantly, the DGEs in ECM–receptor interaction pathway included COL1A1, COL1A2, COL4A1, COL4A2, ITGA11, ITGB3 and SDC3, in the progesterone-mediated oocyte maturation pathway involved CDK1, CDC25A, CCNB3, CDC20 and Plk1, and in the vascular smooth muscle contraction covered CALD1, KCNMA1, KCNMB1, CACNA1, ACTA2, MYH10, MYL3, MYL6, MYL9, closely related to promoting follicular maturation and ovulation in pre-ovulatory follicles. Moreover, it seems that the lysosomal cathepsin family has a decisive role in the regression of early stage of post-ovulatory follicle. Taken together, these data enrich the research of molecular mechanisms of pigeon follicular activities at the transcriptional level and provide novel insight of breeding-related physiology for birds.

Background: Pigeons are significant economic animals in China; however, research regarding the establishment and influencing factors of gut microbiota in squabs remains limited. Understanding how the gut microbiota develops in pigeons, particularly in relation to pigeon milk, is importance in pigeon production. This study aims to elucidate the establishment characteristics of the gut microbiota in White King pigeon squabs and explore the role of pigeon milk in this process.Methods: This study employed 16S rRNA sequencing technology to investigate the dynamics of microbial composition in feces and pigeon milk at various growth stages of White King pigeon. Functional prediction analysis was performed to assess the metabolic pathways involved, and correlation analysis was used to explore the relationships between microbial communities in different sample types.Results: The findings revealed a diverse microbiome present in the meconium of newborn pigeons, with a microbial composition that significantly differed from that of other feces groups. In contrast, the microbial composition of feces (FN) from pigeons aged 7 to 21 days exhibited less variability. At the phylum level, the predominant microbial taxa identified in the feces of FN were Firmicutes, Actinobacteriota, and Proteobacteria. At the genus level, the main dominant bacterial groups included Lactobacillus, Limosilactobacillus, and Turicibacter. Functional prediction analysis indicated that the gut microbiota of pigeons primarily participate in metabolic pathways related to carbohydrates, amino acids, lipids, cofactors, and vitamins. Furthermore, the dominant bacteria found in pigeon milk (MN) were identified as probiotics, including Limosilactobacillus, Ligilactobacillus, Lactobacillus, Bifidobacterium, and Aeriscardovia, which collectively accounted for over 90% of the total abundance. Correlation analysis of the abundance of shared microbes revealed that the association between meconium and feces at the other stages was extremely low. In contrast, the correlation between colostrum and feces at the post-feeding stage were found to be the highest.Conclusion: This study indicates that prenatal colonization occurs in White King pigeons. Notably, within the first week after birth, the gut microbial composition of young pigeons becomes stable. Furthermore, the colostrum serves as the most significant driver for the establishment of intestinal microbiota in squab post-birth. The findings of this study suggest that microorganisms can be added to artificial pigeon milk based on the predominant microbial composition of colostrum. This approach could facilitate the establishment of gut microbiota in young pigeons, thereby promoting their growth and development and providing production benefits.

Human activities have increased the imbalance in atmospheric N and P deposition, which changes soil nutrient availability and subsequently affects the structure and function of terrestrial ecosystems. Dioecious plants are important parts of terrestrial ecosystems and are characterized by sex-related differences in their response to the external environment and always exhibit a skewed sex ratio, which makes them more vulnerable to climate change and increases their risk of extinction. However, little attention has been paid to the effects of unbalanced N and P deposition on these plants, especially on their defense traits. In this study, we used dioecious Populus cathayana to investigate the influence of gradient N and P deposition on the correlation between growth and defense traits. The results showed that although the different rates of N and P deposition enhanced biomass accumulation in both sexes to varying degrees, the most substantial biomass increment was noted under a lower-nitrogen and higher-phosphorus (LNHP) treatment regimen, with females showing an approximately 112% increase and males a 47% increase in total biomass. In response to varying levels of simulated N and P deposition, males and females adopt distinct strategies for biomass allocation. Although declines in root biomass were observed in both sexes as nutrient availability increased, the decrement was more marked in males; under the LNHP treatment, it dropped by about 11%, while under a high-nitrogen and high-phosphorus (HNHP) treatment, the decrease was about 35%. Conversely, females demonstrated a heightened propensity to allocate biomass towards leaf development. Furthermore, with increasing N and P deposition, there was a general reduction in the concentrations of physical and chemical defense substances within the leaves of both sexes. Nonetheless, the correlations between defense substances, nutrient element content, non-structural carbohydrate (NSC) content, and dry biomass were more pronounced in males, suggesting a greater sensitivity to defense substance responses in males than in females. Overall, these results indicate that there is sexual dimorphism in the accumulation of chemical substances in male and female P. cathayana under unbalanced N and P deposition and they provide a technical and theoretical basis for predicting the population dynamics of dioecious plants, maintaining the stability of poplar populations, and constructing high-productivity poplar plantations globally in the future.

Duck egg production, like that of laying hens, follows a typical low–peak–low cycle, reflecting the dynamics of the reproductive system. Post-peak, some ducks undergo a cessation of egg laying, indicative of a regression process in the oviduct. Notably, the magnum, being the longest segment of the oviduct, plays a crucial role in protein secretion. Despite its significance, few studies have investigated the molecular mechanisms underlying oviduct regression in ducks that have ceased laying eggs. In this study, we conducted single-cell transcriptome sequencing on the magnum tissue of Shaoxing ducks at 467 days of age, utilizing the 10× Genomics platform. This approach allowed us to generate a detailed magnum transcriptome map of both egg-laying and ceased-laying ducks. We collected transcriptome data from 13,708 individual cells, which were then subjected to computational analysis, resulting in the identification of 27 distinct cell clusters. Marker genes were subsequently employed to categorize these clusters into specific cell types. Our analysis revealed notable heterogeneity in magnum cells between the egg-laying and ceased-laying ducks, primarily characterized by variations in cells involved in protein secretion and extracellular matrix (ECM)-producing fibroblasts. Specifically, cells engaged in protein secretion were predominantly observed in the egg-laying ducks, indicative of their role in functional albumen deposition within the magnum, a phenomenon not observed in the ceased-laying ducks. Moreover, the proportion of THY1⁺ cells within the ECM-producing fibroblasts was found to be significantly higher in the egg-laying ducks (59%) compared to the ceased-laying ducks (24%). Similarly, TIMP4⁺ fibroblasts constituted a greater proportion of the ECM-producing fibroblasts in the egg-laying ducks (83%) compared to the ceased-laying ducks (58%). These findings suggest a potential correlation between the expression of THY1 and TIMP4 in ECM-producing fibroblasts and oviduct activity during functional reproduction. Our study provides valuable single-cell insights that warrant further investigation into the biological implications of fibroblast subsets in the degeneration of the reproductive tract. Moreover, these insights hold promise for enhancing the production efficiency of laying ducks.