Gut microbiome and serum metabolome analyses identify Bacteroides fragilis as regulators of serotonin content and PRL secretion in broody geese

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.

Transcriptome analysis reveals the genetic basis of crest cushion formation in duck

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.

Mining the key regulatory genes of chicken inosine 5'-monophosphate metabolism based on time series microarray data

IMP （inosine 5＇-monophosphate） is a compound that enhances the flavor of poultry meat. IMP has become a new breeding trait to improve poultry meat quality. We tried to identify several potential regulatory genes, and construct their predicted regulatory relationships. Time series gene expression profiles of thigh muscle tissues of Rugao chicken, a famous indigenous breed in China, were performed for analysis of genes that are co-expressed or correlated with the concentration of IMP. We found 15 crucial co-expression genes, which are Hspa2, Pten, Gabpa, Bpi, Mkll, Srf,, Cd34, Hspa4, EtvS, Bmpr2, Gdel, IgfbpS, Cd28, Pecam1 and Gja1, that may directly or indirectly regulate IMP metabolism. Eventually, we computed the correlation coefficient between 19 IMP Genes and 15 CGs （15 co-expression genes）, and we identified and constructed a predicted regulation network. In conclusion, variation of IMP concentration was primarily connected with the muscle development process. During this process, 15 CGs were identified that may have significant influence on IMP metabolism. In particular, Bmpr2, Pten and co-expression genes correlated with Entpd8 might play important roles in regulating IMP de novo synthesis, decomposition and salvage synthesis.

Molecular cloning and expression patterns of the cholesterol side chain cleavage enzyme(CYP11A1) gene during the reproductive cycle in goose(Anas cygnoides)

Background： CYP11A1, a gene belonging to the family 11 of cytochrome P450, encodes a crucial steroidogenic enzyme that catalyzes the initial step in the production of all classes of steroids. Many studies show that CYP11A1 plays a role in ovary function. However, the role of CYP11A1 in goose reproductive cycle remains largely unknown.Results： In this study, full-length CYP11A1 c DNA of Zhedong goose was obtained using reverse transcription polymerase chain reaction（RT-PCR） and rapid amplification of c DNA ends（RACE）. The c DNA consisted of a 96-base pair（bp） 5′untranslated region（UTR）, a 179-bp 3′UTR and a 1509-bp open reading frame. The open reading frame encodes a putative 503 amino acid protein that shares high homology with CYP11A1 of other birds. The amino acid sequence possesses conserved domains of the P450 superfamily, which include the steroid-binding domain and the heme-binding region. Real-time quantitative polymerase chain reaction（q PCR） analysis revealed CYP11A1 mR NA was expressed ubiquitously in every Zhedong goose tissue analyzed, including the heart, liver, glandular stomach,lung, spleen, kidney, intestinum tenue, intestinum crassum, cerebrum, cerebellum, muscle, oviduct, pituitary,hypothalamus and ovary.. The relatively low levels of CYP11A1 m RNA were detected in pituitary, ovary and oviduct tissues at ovulation when compared with levels at oviposition. Interestingly, higher expression was observed in ovary and oviduct tissues during brooding. Lastly, higher m RNA expression of Yangzhou geese was detected during the ovulation period than that of Zhedong geese.Conclusions： Our findings reveal the sequence characterization and expression patterns of the CYP11A1 gene during the goose reproductive cycle, which may provides correlative evidence that CYP11A1 expression is important in reproduction activity.

The First Crested Duck Genome Reveals Clues to Genetic Compensation and Crest Cushion Formation

The Chinese crested(CC)duck is a unique indigenous waterfowl breed,which has a crest cushion that affects its survival rate.Therefore,the CC duck is an ideal model to investigate the genetic compensation response to maintain genetic stability.In the present study,we first generated a chromosome-level genome of CC ducks.Comparative genomics revealed that genes related to tissue repair,immune function,and tumors were under strong positive selection,indicating that these adaptive changes might enhance cancer resistance and immune response to maintain the genetic stability of CC ducks.We also assembled a Chinese spot-billed(Csp-b)duck genome,and detected the structural variations(SVs)in the genome assemblies of three ducks(i.e.,CC duck,Csp-b duck,and Peking duck).Functional analysis revealed that several SVs were related to the immune system of CC ducks,further strongly suggesting that genetic compensation in the anti-tumor and immune systems supports the survival of CC ducks.Moreover,we confirmed that the CC duck originated from the mallard ducks.Finally,we revealed the physiological and genetic basis of crest traits and identified a causative mutation in TAS2R40 that leads to crest formation.Overall,the findings of this study provide new insights into the role of genetic compensation in adaptive evolution.

Proteomic and phosphoproteomic analysis reveal threonine deficiency increases hepatic lipid deposition in Pekin ducks via reducing STAT phosphorylation

Dietary threonine(Thr)deficiency enhances triglyceride(TG)deposition in the liver of Pekin ducks,which injures hepatic function and impairs growth performance.However,the underlying molecular mechanisms remain unclear.In the present study,we investigated the effects of dietary Thr deficiency on the expressions of proteins and phosphoproteins in liver of Pekin ducks,to identify the underlying molecular changes.A total of 300 one-day-old ducklings were divided into 3 groups with 10 replicates of 10 birds.All ducks were fed corn-wheat-peanut meal diets containing 0.46%,0.71%,and 0.96%Thr,respectively,from 1 to 21 days of age.Growth performance,serum parameters,hepatic TG content,and expression of genes involved in lipid metabolism of Pekin ducks were determined.A Thr deficiency group(Thr-D,0.46%Thr)and a Thr sufficiency group(Thr-S,0.71%Thr)were selected for subsequent proteomic and phosphoproteomic analysis.The results showed that Thr-D reduced the growth performance(P<0.001),and increased the plasma concentrations of cholesterol,high-density lipoprotein cholesterol,low-density lipoprotein cholesterol,and hepatic TG(P<0.05).Thr-D increased gene expression related to fatty acid and TG synthesis(P<0.05).A total of 176 proteins and 259 phosphosites(containing 198 phosphoproteins)were observed to be differentially expressed as a result of Thr-D.The upregulated proteins were enriched in the pathway related to amino acid metabolism,peroxisome.The down-regulated proteins were enriched in linolenic and arachidonic acid metabolism,and the Janus kinase-signal transducer and activator of transcription(JAK-STAT)signaling pathway.The upregulated phos-phoproteins were enriched in the pathways related to fatty acid biosynthesis,fructose and mannose metabolism,and glycolysis/gluconeogenesis.Thr-D reduced the phosphorylation of STAT1 at S729 and STAT3 at S728,and expression of STAT5B.In contrast,Thr-D increased non-receptor tyrosine-protein kinase(TYK2)expression and STAT1 phosphorylation at S649.Taken together,dietary Thr-D increased hepatic TG accumulation by upregulating the expression of genes and proteins,and phosphoproteins related to fatty acid and triglyceride synthesis.Furthermore,these processes might be regulated by the JAK-STAT signaling pathway,especially the phosphorylation of STAT1 and STAT3.