The gut microbiota is a complex ecological community and widely recognized in many aspects of research, but little is known on the relation between gut microbiota and embryonic development in chickens. The aim of this study was to explore the dynamic distribution of gut microbiota in chickens' embryos during stages of developments (chicken embryos that had incubated until day 3 [E3], day 12 [E12], and day 19 [E19]). Here, 16S rRNA gene sequencing was performed on the gut microbiota in chicken embryos across different developmental stages. Twenty-one phyla and 601 genera were present in chicken embryos, and 96 genera such as Ochrobactrum , Phyllobacterium, and Amycolatopsis were the core microbiota in the 3 stages of development. Second, 94 genera of microbes were found to change significantly between E3 and E12, and 143 genera significantly differed between E12 and E19 in chicken embryos ( P < 0.05). Ochrobactrum and Amycolatopsis decreased with growth changes: E3 (30.4%), E12 (25.1%), and E19 (13.6%) and E3 (11.5%), E12 (7.4%), and E19 (5.6%), respectively. Contrarily, Phyllobacterium increased to 47.9% at E19, indicating the growing trend of microbial diversity among the embryos' development. Moreover, the principal component analysis showed a high level of similarities between E3 and E12 compared with E19, whereas the alpha analysis showed more diversity of gut microbiota at E19. Furthermore, the functional predictions showed that metabolic pathways such as energy metabolism and genetic information processing were significantly enriched on day 3 and day 12 in our study, suggesting their strong influence on growth, development, and immunity of chicken embryos. Our findings provide insights into the understanding of dynamic shifts of gut microbiota during chicken embryonic growth.

Mammalian neonates obtain antibodies, nutrients, and microbiota from breast milk that help them resist the complex growth environment. Similar to mammals’ lactation behavior for their offspring, parent pigeons regurgitate pigeon milk (PM) from their crops to feed the squabs. Whether pigeon milk is as valuable as mammalian milk is not clear, especially in terms of microbiota. This study adopted 16S rRNA gene sequencing to investigate the microbial composition and function in pigeon milk. We found abundant microbiota in pigeon milk. The dominant genera in parent pigeons’ milk were Lactobacillus , Enterococcus , Veillonella , and Bifidobacterium . An analysis of squab milk (SM) showed that Lactobacillus also accounted for a considerable proportion, followed by Bifidobacterium . Most of the squab milk microbial genera were also detected in parent pigeons. Microbial functional analysis showed that the squab milk microbes were more involved in the pathways of carbohydrate metabolism, amino acid metabolism, and energy metabolism. These findings indicated that microbiota play an important role in squabs and can be transmitted from parent pigeons to squabs by pigeon milk. The presence of plentiful probiotics in squabs also suggests that adding probiotics in artificial pigeon milk may promote the growth and development of squabs and improve the production performance of pigeons.

The common pheasant Phasianus colchicus, belonging to the order Galliformes and family Phasianidae, is the most widespread species. Despite a long history of captivity, the domestication of this bird is still at a preliminary stage. Recently, the demand for accelerating its transformation to poultry for meat and egg production has been increasing. In this study, we assembled high quality, chromosome scale genome of the common pheasant by using PacBio long reads, next‐generation short reads, and Hi‐C technology. The primary assembly has contig N50 size of 1.33 Mb and scaffold N50 size of 59.46 Mb, with a total size of 0.99 Gb, resolving most macrochromosomes into single scaffolds. A total of 23,058 genes and 10.71 Mb interspersed repeats were identified, constituting 30.31% and 10.71% of the common pheasant genome, respectively. Our phylogenetic analysis revealed that the common pheasant shared common ancestors with turkey about 24.7–34.5 million years ago (Ma). Rapidly evolved gene families, as well as branch‐specific positively selected genes, indicate that calcium‐related genes are potentially related to the adaptive and evolutionary change of the common pheasant. Interestingly, we found that the common pheasant has a unique major histocompatibility complex B locus (MHC‐B) structure: three major inversions occurred in the sequence compared with chicken MHC‐B. Furthermore, we detected signals of selection in five breeds of domestic common pheasant, several of which are production‐oriented.

Reporter genes are widely applied in biotechnology and biomedical research owning to their easy observation and lack of toxicity. Taking advantage of the reporter genes in conjunction with imaging technologies, a large number of reporter mouse models have been generated. Reporter mouse models provide systems that enable the studies of live cell imaging, cell lineage tracing, immunological research and cancers etc. in vivo. In this review, we describe the types of different reporter genes and reporter mouse models including, random reporter strains, Cre reporter strains and ROSA 26 reporter strains. Collectively, these reporter mouse models have broadened scientific inquires and provided potential strategies for generation of novel reporter animal models with enhanced capabilities.

Pullorum disease is one of the most common diarrhea-related diseases caused by Salmonella enterica subspecies enterica serovar Gallinarum biovar Pullorum (S. Pullorum); it negatively affects the poultry industry. However, limited studies have explored the association between the gut microbiota and S. Pullorum infection in chickens. In the present study, we performed a microbiome comparison and a microbiome genome-wide association study (mGWAS) to investigate the association among the host genetics, the gut microbiota, and pullorum disease in chickens. We found that S. Pullorum infection in chickens could alter the abundance of 39 bacterial genera (P < 0.05). The altered structure and composition of the gut microbiota were also detected in the offspring. mGWAS results revealed host genetic variants to be prominently associated with gut microbial diversity and individual microbes. The pathogens Pelomonas and Brevundimonas, which had a high abundance in positive parent chickens and their offspring, were significantly associated with several genetic mutations in immunity-related genes, such as TGIF1, TTLL12, and CCR7. This finding explained why Pelomonas and Brevundimonas were heritable in S. Pullorum-infected chickens. The heritable gut microbes and identified genetic variants could provide references for the selection of resistant chickens and the elimination of pullorum disease. IMPORTANCE The present study investigated the association among the host genome, the gut microbiome, and S. Pullorum infection in chickens. The results suggested that the gut microbial structure is altered in S. Pullorum-infected chickens. The diversity and abundance of the gut microbiota remarkably differed between the offspring coming from S. Pullorum-positive and S. Pullorum-negative chickens. Heritable gut microbiota were detected in the offspring. Moreover, host genetic variants were associated with microbial diversity and individual gut microbes. The pathogens Pelomonas and Brevundimonas, which exhibited a high heritability in S. Pullorum-positive parents and their offspring, were associated with several genetic mutations in immunity-related genes.