Exploring the dynamic three-dimensional chromatin architecture and transcriptional landscape in goose liver tissues underlying metabolic adaptations induced by a high-fat diet.

BACKGROUND: Goose, descendants of migratory ancestors, have undergone extensive selective breeding, resulting in their remarkable ability to accumulate fat in the liver and exhibit a high tolerance for significant energy intake. As a result, goose offers an excellent model for studying obesity, metabolic disorders, and liver diseases in mammals. Although the impact of the three-dimensional arrangement of chromatin within the cell nucleus on gene expression and transcriptional regulation is widely acknowledged, the precise functions of chromatin architecture reorganization during fat deposition in goose liver tissues still need to be fully comprehended. RESULTS: In this study, geese exhibited more pronounced changes in the liver index and triglyceride (TG) content following the consumption of the high-fat diet (HFD) than mice without significant signs of inflammation. Additionally, we performed comprehensive analyses on 10 goose liver tissues (5 HFD, 5 normal), including generating high-resolution maps of chromatin architecture, conducting whole-genome gene expression profiling, and identifying H3K27ac peaks in the livers of geese and mice subjected to the HFD. Our results unveiled a multiscale restructuring of chromatin architecture, encompassing Compartment A/B, topologically associated domains, and interactions between promoters and enhancers. The dynamism of the three-dimensional genome architecture, prompted by the HFD, assumed a pivotal role in the transcriptional regulation of crucial genes. Furthermore, we identified genes that regulate chromatin conformation changes, contributing to the metabolic adaptation process of lipid deposition and hepatic fat changes in geese in response to excessive energy intake. Moreover, we conducted a cross-species analysis comparing geese and mice exposed to the HFD, revealing unique characteristics specific to the goose liver compared to a mouse. These chromatin conformation changes help elucidate the observed characteristics of fat deposition and hepatic fat regulation in geese under conditions of excessive energy intake. CONCLUSIONS: We examined the dynamic modifications in three-dimensional chromatin architecture and gene expression induced by an HFD in goose liver tissues. We conducted a cross-species analysis comparing that of mice. Our results contribute significant insights into the chromatin architecture of goose liver tissues, offering a novel perspective for investigating mammal liver diseases.

Modulation of Performance, Plasma Constituents, Small Intestinal Morphology, and Cecum Microbiota in Growing Geese by Dietary Citric Acid Supplementation.

To investigate the efficiency and optimum inclusion level of CA in growing geese diets on performance, plasma constituents, and intestinal health, 240 healthy female geese at the age of 28d were randomly allotted six treatment diets incorporated with 0, 0.8, 1.6, 2.4, 3.2, and 4% CA. Each treatment group consisted of five replicates and eight birds per replicate. The findings demonstrated that 3.2% CA supplementation resulted in improved growth performance (ADG, ADFI, and FBW) (p = 0.001), and geese who received CA also showed lower body fat contents (p < 0.05) than the control group. Moreover, geese from the 2.4% and 3.2% CA group had the highest plasma glutathione peroxidase and insulin-like growth factor 1 levels compared to the other groups (p < 0.05). A microbial diversity analysis of the cecum conducted by 16S rDNA sequencing revealed that 3.2% CA supplementation showed a significantly higher abundance of beneficial bacteria (Muribaculaceae, CHKCI001, Erysipelotricha-ceae_UCG_003, and UCG_009) (p < 0.05) and a lower abundance of harmful bacteria (Atopobiaceae, Streptococcus, Acinetobacter, Pseudomonas, and Alistipes) (p < 0.10). Collectively, our results revealed that dietary supplementation with 3.2% CA had several benefits on the performance and physiological health of growing geese by promoting nutrients metabolism, improving antioxidant capacity, and modulating cecum microbiota.

Effects of Heat Stress and Lipopolysaccharides on Gene Expression in Chicken Immune Cells.

Prolonged exposure to high temperatures and humidity can trigger heat stress in animals, leading to subsequent immune suppression. Lipopolysaccharides (LPSs) act as upstream regulators closely linked to heat stress, contributing to their immunosuppressive effects. After an initial examination of transcriptome sequencing data from individual samples, 48 genes displaying interactions were found to potentially be associated with heat stress. Subsequently, to delve deeper into this association, we gathered chicken bone marrow dendritic cells (BMDCs). We combined heat stress with lipopolysaccharides and utilized a 48 × 48 Fluidigm IFC quantitative microarray to analyze the patterns of gene changes under various treatment conditions. The results of the study revealed that the combination of heat stress and LPSs in a coinfection led to reduced expressions of CRHR1, MEOX1, and MOV10L1. These differentially expressed genes triggered a pro-inflammatory response within cells via the MAPK and IL-17 signaling pathways. This response, in turn, affected the intensity and duration of inflammation when experiencing synergistic stimulation. Therefore, LPSs exacerbate the immunosuppressive effects of heat stress and prolong cellular adaptation to stress. The combination of heat stress and LPS stimulation induced a cellular inflammatory response through pathways involving cAMP, IL-17, MAPK, and others, consequently leading to decreased expression levels of CRHR1, MEOX1, and MOV10L1.

Insights into genetic diversity and phenotypic variations in domestic geese through comprehensive population and pan-genome analysis.

BACKGROUND: Domestic goose breeds are descended from either the Swan goose (Anser cygnoides) or the Greylag goose (Anser anser), exhibiting variations in body size, reproductive performance, egg production, feather color, and other phenotypic traits. Constructing a pan-genome facilitates a thorough identification of genetic variations, thereby deepening our comprehension of the molecular mechanisms underlying genetic diversity and phenotypic variability. RESULTS: To comprehensively facilitate population genomic and pan-genomic analyses in geese, we embarked on the task of 659 geese whole genome resequencing data and compiling a database of 155 RNA-seq samples. By constructing the pan-genome for geese, we generated non-reference contigs totaling 612 Mb, unveiling a collection of 2,813 novel genes and pinpointing 15,567 core genes, 1,324 softcore genes, 2,734 shell genes, and 878 cloud genes in goose genomes. Furthermore, we detected an 81.97 Mb genomic region showing signs of genome selection, encompassing the TGFBR2 gene correlated with variations in body weight among geese. Genome-wide association studies utilizing single nucleotide polymorphisms (SNPs) and presence-absence variation revealed significant genomic associations with various goose meat quality, reproductive, and body composition traits. For instance, a gene encoding the SVEP1 protein was linked to carcass oblique length, and a distinct gene-CDS haplotype of the SVEP1 gene exhibited an association with carcass oblique length. Notably, the pan-genome analysis revealed enrichment of variable genes in the "hair follicle maturation" Gene Ontology term, potentially linked to the selection of feather-related traits in geese. A gene presence-absence variation analysis suggested a reduced frequency of genes associated with "regulation of heart contraction" in domesticated geese compared to their wild counterparts. Our study provided novel insights into gene expression features and functions by integrating gene expression patterns across multiple organs and tissues in geese and analyzing population variation. CONCLUSION: This accomplishment originates from the discernment of a multitude of selection signals and candidate genes associated with a wide array of traits, thereby markedly enhancing our understanding of the processes underlying domestication and breeding in geese. Moreover, assembling the pan-genome for geese has yielded a comprehensive apprehension of the goose genome, establishing it as an indispensable asset poised to offer innovative viewpoints and make substantial contributions to future geese breeding initiatives.

Identification of SNPs Associated with Goose Meat Quality Traits Using a Genome-Wide Association Study Approach.

(1) Background: Goose meat is highly valued for its economic significance and vast market potential due to its desirable qualities, including a rich nutritional profile, tender texture, relatively low-fat content, and high levels of beneficial unsaturated fatty acids. However, there is an urgent need to improve goose breeding by identifying molecular markers associated with meat quality. (2) Methods: We evaluated meat quality traits, such as meat color, shear force (SF), cooking loss rate (CLR), and crude fat content (CFC), in a population of 215 male Sichuan white geese at 70 days of age. A GWAS was performed to identify potential molecular markers associated with goose meat quality. Furthermore, the selected SNPs linked to meat quality traits were genotyped using the MALDI-TOP MS method. (3) Results: A dataset of 2601.19 Gb of WGS data was obtained from 215 individuals, with an average sequencing depth of 10.89×. The GWAS revealed the identification of 43 potentially significant SNP markers associated with meat quality traits in the Sichuan white goose population. Additionally, 28 genes were identified as important candidate genes for meat quality. The gene enrichment analysis indicated a substantial enrichment of genes within a 1Mb vicinity of SNPs in both the protein digestion and absorption pathway and the Glycerolipid metabolism pathway. (4) Conclusion: This study provides valuable insights into the genetic and molecular mechanisms underlying goose meat quality traits, offering crucial references for molecular breeding in this field.

Genome-Wide Identification and Characterization of Long Non-Coding RNAs in Embryo Muscle of Chicken.

Embryonic muscle development determines the state of muscle development and muscle morphological structure size. Recent studies have found that long non-coding RNAs (lncRNAs) could influence numerous cellular processes and regulated growth and development of flora and fauna. A total of 1056 differentially expressed lncRNAs were identified by comparing the different time points during embryonic muscle development, which included 874 new lncRNAs. Here, we found that there were different gene expression patterns on the 12th day of embryo development (E12). Herein, WGCNA and correlation analyses were used to predict lncRNA function on E12 through the screening and identification of lncRNAs related to muscle development in the embryo leg muscles of Chengkou mountain chickens at different times. GO and KEGG functional enrichment analysis was performed on target genes involved in cis-regulation and trans-regulation. An interaction network diagram was constructed based on the muscle development pathways, such as Wnt, FoxO, and PI3K-AKT signaling pathways, to determine the interaction between mRNAs and lncRNAs. This study preliminarily determined the lncRNA expression pattern of muscle development during the middle and late embryonic stages of Chengkou mountain chickens, and provided a basis to analyze the molecular mechanism of muscle development.

Transcriptome analysis of embryonic muscle development in Chengkou Mountain Chicken.

BACKGROUND: Muscle is the predominant portion of any meat product, and growth performance and product quality are the core of modern breeding. The embryonic period is highly critical for muscle development, the number, shape and structure of muscle fibers are determined at the embryonic stage. Herein, we performed transcriptome analysis to reveal the law of muscle development in the embryonic stage of Chengkou Mountain Chicken at embryonic days (E) 12, 16, 19, 21. RESULTS: Diameter and area of muscle fibers exhibited significant difference at different embryonic times(P < 0.01). A total of 16,330 mRNAs transcripts were detected, including 109 novel mRNAs transcripts. By comparing different embryonic muscle development time points, 2,262 in E12vsE16, 5,058 in E12vsE19, 6139 in E12vsE21, 1,282 in E16vsE19, 2,920 in E16vsE21, and 646 in E19vsE21differentially expressed mRNAs were identified. It is worth noting that 7,572 mRNAs were differentially expressed. The time-series expression profile of differentially expressed genes (DEGs) showed that the rising and falling expression trends were significantly enriched. The significant enrichment trends included 3,150 DEGs. GO enrichment analysis provided three significantly enriched categories of significantly enriched differential genes, including 65 cellular components, 88 molecular functions, and 453 biological processes. Through KEGG analysis, we explored the biological metabolic pathways involved in differentially expressed genes. A total of 177 KEGG pathways were enriched, including 19 significant pathways, such as extracellular matrix-receptor interactions. Similarly, numerous pathways related to muscle development were found, including the Wnt signaling pathway (P < 0.05), MAPK signalingpathway, TGF-beta signaling pathway, PI3K-Akt signaling pathway and mTOR signaling pathway. Among the differentially expressed genes, we selected those involved in developing 4-time points; notably, up-regulated genes included MYH1F, SLC25A12, and HADHB, whereas the down-regulated genes included STMN1, VASH2, and TUBAL3. CONCLUSIONS: Our study explored the embryonic muscle development of the Chengkou Mountain Chicken. A large number of DEGs related to muscle development have been identified ,and validation of key genes for embryonic development and preliminary explanation of their role in muscle development. Overall, this study broadened our current understanding of the phenotypic mechanism for myofiber formation and provides valuable information for improving chicken quality.

Genome-Wide Association Study-Based Identification of SNPs and Haplotypes Associated With Goose Reproductive Performance and Egg Quality.

Geese are one of the most economically important waterfowl. However, the low reproductive performance and egg quality of geese hinder the development of the goose industry. The identification and application of genetic markers may improve the accuracy of beneficial trait selection. To identify the genetic markers associated with goose reproductive performance and egg quality traits, we performed a genome-wide association study (GWAS) for body weight at birth (BBW), the number of eggs at 48 weeks of age (EN48), the number of eggs at 60 weeks of age (EN60) and egg yolk color (EYC). The GWAS acquired 2.896 Tb of raw sequencing data with an average depth of 12.44× and identified 9,279,339 SNPs. The results of GWAS showed that 26 SNPs were significantly associated with BBW, EN48, EN60, and EYC. Moreover, five of these SNPs significantly associated with EN48 and EN60 were in a haplotype block on chromosome 35 from 4,512,855 to 4,541,709 bp, oriented to TMEM161A and another five SNPs significantly correlated to EYC were constructed in haplotype block on chromosome 5 from 21,069,009 to 21,363,580, which annotated by TMEM161A, CALCR, TFPI2, and GLP1R. Those genes were enriched in epidermal growth factor-activated receptor activity, regulation of epidermal growth factor receptor signaling pathway. The SNPs, haplotype markers, and candidate genes identified in this study can be used to improve the accuracy of marker-assisted selection for the reproductive performance and egg quality traits of geese. In addition, the candidate genes significantly associated with these traits may provide a foundation for better understanding the mechanisms underlying reproduction and egg quality in geese.

Genome-Wide Gene Expression Profiles Reveal Distinct Molecular Characteristics of the Goose Granulosa Cells.

Granulosa cells (GCs) are decisive players in follicular development. In this study, the follicle tissues and GCs were isolated from the goose during the peak-laying period to perform hematoxylin-eosin staining and RNA-seq, respectively. Moreover, the dynamic mRNA and lncRNA expression profiles and mRNA-lncRNA network analysis were integrated to identify the important genes and lncRNAs. The morphological analysis showed that the size of the GCs did not significantly change, but the thickness of the granulosa layer cells differed significantly across the developmental stages. Subsequently, 14,286 mRNAs, 3,956 lncRNAs, and 1,329 TUCPs (transcripts with unknown coding potential) were detected in the GCs. We identified 37 common DEGs in the pre-hierarchical and hierarchical follicle stages, respectively, which might be critical for follicle development. Moreover, 3,089 significant time-course DEGs (Differentially expressed genes) and 13 core genes in 4 clusters were screened during goose GCs development. Finally, the network lncRNA G8399 with CADH5 and KLF2, and lncRNA G8399 with LARP6 and EOMES were found to be important for follicular development in GCs. Thus, the results would provide a rich resource for elucidating the reproductive biology of geese and accelerate the improvement of the egg-laying performance of geese.

General hierarchical structure to solve transport phenomena with dissimilar time scales: Application in large-scale three-dimensional thermosolutal phase-field problems.

A general hierarchical structure is developed for phase-field lattice-Boltzmann simulations with dissimilar time scales. The number of the grid levels can be artificially selected in a reasonable range, which can enhance the time marching step by two to three orders of magnitude in comparison with explicit methods. Constructed on a massively parallel platform, the mesh distribution is dynamically adjusted according to a gradient criterion. The developed high performance computing scheme is applied to simulate the coupled thermosolutal dendrite evolution. Numerical tests indicate that the computing efficiency can be further improved by two to three orders of magnitude, which makes numerical simulation of fully coupled thermosolutal dendrite growth viable for alloys with Lewis number ∼10^{4}. The domain size which equivalently consists of billions of uniform meshes is handled to simulate multidendrite evolution. Results show that the domain temperature becomes extremely uneven due to the release of latent heat, which causes a significant difference from isothermal solidification. A simple analytical model is proposed to predict the relation between growth velocity and Lewis number, and the growth morphologies of both equiaxed and directional multiple dendrites are discussed. The combination of the hierarchical mesh structure and the phase-field lattice-Boltzmann method provides an efficiency-driven approach to solve the coupled thermosolutal microstructure evolution.

Pacific Biosciences assembly with Hi-C mapping generates an improved, chromosome-level goose genome.

BACKGROUND: The domestic goose is an economically important and scientifically valuable waterfowl; however, a lack of high-quality genomic data has hindered research concerning its genome, genetics, and breeding. As domestic geese breeds derive from both the swan goose (Anser cygnoides) and the graylag goose (Anser anser), we selected a female Tianfu goose for genome sequencing. We generated a chromosome-level goose genome assembly by adopting a hybrid de novo assembly approach that combined Pacific Biosciences single-molecule real-time sequencing, high-throughput chromatin conformation capture mapping, and Illumina short-read sequencing. FINDINGS: We generated a 1.11-Gb goose genome with contig and scaffold N50 values of 1.85 and 33.12 Mb, respectively. The assembly contains 39 pseudo-chromosomes (2n = 78) accounting for ∼88.36% of the goose genome. Compared with previous goose assemblies, our assembly has more continuity, completeness, and accuracy; the annotation of core eukaryotic genes and universal single-copy orthologs has also been improved. We have identified 17,568 protein-coding genes and a repeat content of 8.67% (96.57 Mb) in this genome assembly. We also explored the spatial organization of chromatin and gene expression in the goose liver tissues, in terms of inter-pseudo-chromosomal interaction patterns, compartments, topologically associating domains, and promoter-enhancer interactions. CONCLUSIONS: We present the first chromosome-level assembly of the goose genome. This will be a valuable resource for future genetic and genomic studies on geese.

Regulating lamellar eutectic trajectory through external perturbations.

The present understanding of asymmetric lamellar eutectics focuses on pure diffusive transport, and how the external perturbations cause asymmetric pattern transitions remains unclear. In this work, the effect of external perturbations is discussed in terms of both thermal and convective effects via phase-field modeling. The presence of thermal perturbation distorts eutectic lamellae, while the convective perturbation causes a tilt band. Both can adjust the eutectic trajectory to accommodate newly established thermodynamics by reconstructing the transport equilibrium. Furthermore, how to regulate the eutectic growth (eutectic colony, zigzag, and snakelike patterns) by altering external perturbations is investigated, which provides information on how to control eutectic evolution.

Microevolutionary Dynamics of Chicken Genomes under Divergent Selection for Adiposity.

Decades of artificial selection have significantly improved performance and efficiency of animal production systems. However, little is known about the microevolution of genomes due to intensive breeding. Using whole-genome sequencing, we document dynamic changes of chicken genomes under divergent selection on adiposity over 19 generations. Directional selection reduced within-line but increased between-line genomic differences. We observed that artificial selection tended to result in recruitment of preexisting variations of genes related to adipose tissue growth. In addition, novel mutations contributed to divergence of phenotypes under selection but contributed significantly less than preexisting genomic variants. Integration of 15 generations genome sequencing, genome-wide association study, and multi-omics data further identified that genes involved in signaling pathways important to adipogenesis, such as autophagy and lysosome (URI1, MBL2), neural system (CHAT), and endocrine (PCSK1) pathways, were under strong selection. Our study provides insights into the microevolutionary dynamics of domestic animal genomes under artificial selection.

Physiological Implications of Orexins/Hypocretins on Energy Metabolism and Adipose Tissue Development.

Orexins/hypocretins and their receptors (OXRs) are ubiquitously distributed throughout the nervous system and peripheral tissues. Recently, various reports have indicated that orexins play regulatory roles in numerous physiological processes involved in obesity, energy homeostasis, sleep-wake cycle, analgesia, alcoholism, learning, and memory. This review aims to outline recent progress in the research and development of orexins used in biochemical signaling pathways, secretion pathways, and the regulation of energy metabolism/adipose tissue development. Orexins regulate a variety of physiological functions in the body by activating phospholipase C/protein kinase C and AC/cAMP/PKA pathways, through receptors coupled to Gq and Gi/Gs, respectively. The secretion of orexins is modulated by blood glucose, blood lipids, hormones, and neuropeptides. Orexins have critical functions in energy metabolism, regulating both feeding behavior and energy expenditure. Increasing the sensitivity of orexin-coupled hypothalamic neurons concurrently enhances spontaneous physical activity, non-exercise activity thermogenesis, white adipose tissue lipolysis, and brown adipose tissue thermogenesis. With this comprehensive review of the current literature on the subject, we hope to provide an integrated perspective for the prevention/treatment of obesity.

Conservative phase-field method with a parallel and adaptive-mesh-refinement technique for interface tracking.

Based on Fick's second law and Cahn-Hilliard theory, a conservative phase-field model is developed to track interface. The phase-field variable changes in a hyperbolic tangent behavior across the diffuse interface over which the interface curvature can be easily calculated. Different from the frequently used lattice-Boltzmann-based discrete method, the phase-field equation is discretized using a fourth-order Runge-Kutta method. Accordingly, the present numerical scheme alleviates the programming burden, reduces the memory usage, but maintains a high numerical accuracy. To achieve large-scale interface tracking, a parallel and adaptive-mesh-refinement algorithm is developed to reduce the computing overhead. Various cases of the interface evolutions under steady flow fields indicate that the proposed numerical scheme can capture the interface with high accuracy. Furthermore, the robustness of the numerical scheme is validated by simulating the Rayleigh-Taylor instability, and good agreement with previous work is achieved.

Influence of Two-Stage Combinations of Constructed Wetlands on the Removal of Antibiotics, Antibiotic Resistance Genes and Nutrients from Goose Wastewater.

Antibiotic and antibiotic resistance genes (ARGs) have been considered as emerging environmental contaminants and possess potential crisis to global public health. However, little is known about the differences between various configurations of two-stage combinations of constructed wetlands (CWs) on antibiotics and ARG removal from wastewater. In the study, three configurations of two-stage hybrid CWs (horizontal subsurface flow-down-flow vertical subsurface flow CWs, HF-DVF; horizontal subsurface flow-up-flow vertical subsurface flow CWs, HF-UVF; down-flow vertical subsurface flow-up-flow vertical subsurface flow CWs, DVF-UVF) were operated to evaluate their ability to remove high-concentration antibiotics (tilmicosin-TMS and doxycycline-DOC), ARGs (seven tet genes and three erm genes), intI1, 16S rRNA, and nutrients from goose wastewater. The results showed that all three hybrid CWs could remove more than 98% of TMS and DOC from wastewater, without significant difference among treatments (p > 0.05). For ARGs, DVF-UVF showed significantly higher removal efficiencies of intI1, ermB, ermC, ermF, tetW, and tetG compared to HF-UVF (p < 0.05), mainly because they might remove and arrest growth of bacteria. The relatively high removal efficiencies of NH4+-N, NO3-N, and NO2--N were also observed from DVF-UVF, ranging from 87% to 95% (p > 0.05), indicating that anaerobic ammonium oxidation (anammox) might be established in the CWs. Our results demonstrate that the removal performances of antibiotics using two-stage hybrid CWs are not affected by the combined configuration, whereas the combination of DVF and UVF CWs perform better on the removal of ARGs and nutrients compared with HF-DVF and HF-UVF CWs.

Nutritive Value of Sorghum Dried Distillers Grains with Solubles and its Effect on Performance in Geese.

The study was conducted to determine the chemical composition and nutritive value of sorghum dried distillers grains with solubles (sDDGS) and its effect as a feed supplement on the performance of geese. Experiment 1 showed that the gross energy, crude protein, ether extract, crude fiber, calcium, phosphorus, and amino acid content values of sDDGS were 17.87 MJ/kg and 15.48, 4.26, 31.46, 0.17, 0.25, and 0.06-3.18% [dry matter basis (DM)], respectively. Experiment 2 used fasting-force feeding to measure the true metabolizable energy of sDDGS (11.38 MJ/kg DM) and true total tract digestibility of amino acids (43.16-80.92% DM) in geese. Experiment 3 examined the effectiveness of sDDGS as a feed supplement for geese. Three hundred and fifteen 35-day-old male Sichuan white geese with an initial average bodyweight of 1,732 g were randomly allocated to five treatments. Geese in each treatment group were fed one of five experimental diets (control diet alone, or supplemented with 4, 8, 12, or 16% sDDGS) until 70 days of age. Inclusion of sDDGS in the diet did not affect daily average weight gain (P>0.05). Birds fed diets containing up to 8% sDDGS had higher average feed intake (P<0.05) than geese fed the control diet, and the feed/gain ratio in geese fed diets containing 16% sDDGS was higher (P<0.05) than in the control and the 4% sDDGS group. The yields of breast meat, leg meat, subcutaneous fat and skin, and abdominal fat were not affected (P>0.05) bydietary sDDGS levels. Generally, sDDGS is a potentially valuable feedstuff for geese, but it should be supplemented with a high-energy or protein-rich ingredient. To improve growth performance and carcass yield, up to 12% sDDGS can be included in diets from 35 to 70 days of age.

Goose FMO3 gene cloning, tissue expression profiling, polymorphism detection and association analysis with trimethylamine level in the egg yolk.

Flavin-containing monooxygenase 3 (FMO3) plays a critical role in catalyzing the conversion of trimethylamine (TMA) to trimethylamine-N-oxide (TMAO) in vivo. Despite the well-documented association between FMO3 mutations and a 'fishy' off-flavor eggs in chicken and quail, little information is available regarding the molecular characteristic of goose (Anser cygnoides) FMO3 and its relationship with the yolk TMA content. To fill these gaps, we cloned the full-length cDNA sequence of goose FMO3, which comprised 1851bp encoding 531 amino acids. FMO3 mRNA was dramatically expressed in liver than in other tissues in the geese. Eight single nucleotide polymorphisms (SNPs) were detected in the entire coding region. The CC genotype at the T669C site, GG at the A723G site, and AA at the G734A site of FMO3 were highly significantly associated with elevated TMA content in goose egg yolk (P<0.001). Carriers of the A allele of G734A or C allele of T885C had yolk TMA content that had a high probability of being elevated after feeding with additional choline chloride (P=0.0429, OR=4.1300, 95%CI=1.0390-16.4270, and P=0.0251, OR=4.6060, 95%CI=1.1620-18.2620, respectively). This work lays a foundation for studying the function of FMO3 and yolk TMA content in goose. However, studies using larger sample sizes and more goose breeds are required to determine whether the fishy off-flavor trait exists in goose.

Nutritive Value of Mulberry Leaf Meal and its Effect on the Performance of 35-70-Day-Old Geese.

Availability of feed crops for animal production is decreasing, creating a need to identify alternative food sources. With their high protein content, mulberry leaves are a likely candidate for feed supplementation and have been trialed on pigs and chickens, but little is known about their effect as a feed supplement on geese. Here, we determine the nutritive value of mulberry leaf meal (MLM), measure the digestibility of energy and amino acid of MLM in male Sichuan white geese, and evaluate the performance of these geese fed an MLM-supplemented diet. The composition of MLM was as follows: gross energy 4.94 Mcal/kg, crude protein 18.81%, ether extract 11.65%, crude fiber 12.45%, calcium 2.46%, phosphorous 0.24% and amino acids 0.26-1.92% (all % on a dry matter basis). Using the emptying then force-feeding method on 24 geese aged 194 days, we measured the apparent metabolizable energy of MLM as 1.58 Mcal/kg (on a dry matter basis), and the true total tract digestibility of the amino acids in MLM as 50.54-79.98%. We then randomly allocated a further 210 geese aged 35 days to one of five dietary treatments (control diet alone or supplemented with 4%, 8%, 12% or 16% MLM). Each treatment contained six replicate pens of seven birds per pen, and birds were maintained on their treatment until 70 days of age. Geese fed diets containing MLM exhibited lower weight gains, elevated feed consumption and an increased feed to gain ratio (P<0.05) compared with geese fed the control diet. Moreover, geese fed diets supplemented with MLM all experienced diarrhea, reduced amounts of subcutaneous fat and lower percentages of skin and abdominal fat (P<0.05) compared with control geese. In conclusion, MLM should be used with caution as a feed supplement for geese.

Genome and metagenome analyses reveal adaptive evolution of the host and interaction with the gut microbiota in the goose.

The goose is an economically important waterfowl that exhibits unique characteristics and abilities, such as liver fat deposition and fibre digestion. Here, we report de novo whole-genome assemblies for the goose and swan goose and describe the evolutionary relationships among 7 bird species, including domestic and wild geese, which diverged approximately 3.4~6.3 million years ago (Mya). In contrast to chickens as a proximal species, the expanded and rapidly evolving genes found in the goose genome are mainly involved in metabolism, including energy, amino acid and carbohydrate metabolism. Further integrated analysis of the host genome and gut metagenome indicated that the most widely shared functional enrichment of genes occurs for functions such as glycolysis/gluconeogenesis, starch and sucrose metabolism, propanoate metabolism and the citrate cycle. We speculate that the unique physiological abilities of geese benefit from the adaptive evolution of the host genome and symbiotic interactions with gut microbes.