Two cis-regulatory SNPs upstream of ABCG2 synergistically cause the blue eggshell phenotype in the duck.

Avian eggshell color is an interesting genetic trait. Here, we report that the blue eggshell color of the domestic duck is caused by two cis-regulatory G to A transitions upstream of ABCG2, which encodes an efflux transporter. The juxtaposed blue eggshell allele A-A exhibited higher promoter activity and stronger nuclear protein binding capacity than the white eggshell allele G-G. Transcription factor analysis suggested differential binding capability of CTCF between blue eggshell and white eggshell alleles. Knockdown of CTCF expression significantly decreased the promoter activity of the blue eggshell but not the white eggshell allele. DNA methylation analysis revealed similar high methylation of the region upstream of the CTCF binding sites in both blue-eggshelled and white-eggshelled ducks. However, DNA methylation levels downstream of the binding sites were decreased and 35% lower in blue-eggshelled ducks than in white-eggshelled ducks. Consistent with the in vitro regulatory pattern of causative sites, ABCG2 exhibited higher expression in uteruses of blue-eggshelled ducks and also showed polarized distribution in their endometrial epithelial cells, distributing at the apical surface of endometrial epithelial cells and with orientation toward the uterine cavity, where the eggshell is pigmented. In conclusion, our results suggest that two cis-regulatory SNPs upstream of ABCG2 are the causative mutations for blue eggshells in ducks. The blue eggshell variant up-regulated ABCG2 expression through recruiting CTCF binding, which may function as a barrier element to shield the downstream region from high methylation levels present upstream. ABCG2 was identified as the only candidate causative gene for blue eggshells; it may function as an efflux transporter of biliverdin to the uterine cavity.

Immunopromoter improves liver apoptosis and immune response in Shaoxing ducklings.

Antibiotics as feed additives, play a vital role in animal husbandry. However, overused antibiotics could cause endogenous infections in animals, and even endanger human health through the food chain. And immunopotentiators can make the low immune function improve and accelerate the induction of immune response. The aim of this study was to investigate the effects of five different immunopotentiators on the expression of liver apoptosis and immune factor related genes in Shaoxing ducklings (Anas Platyrhynchos). A total of 150 one-day-old Shaoxing ducklings were randomly divided into six groups including saline, chlorogenic acid, ß-D-glucan, astragalus flavone, CpG DNA and chicken IgG, which were injected subcutaneously into the neck, respectively. At 18 days old, the liver tissues were collected to detecte the mRNA and protein expression levels of inflammatory and apoptosis-related genes. The results showed that compared with the control group, the mRNA and protein levels of liver Bcl2 with chlorogenic acid, ß-D-glucan, astragalus flavone, CpG-DNA and chicken IgG were significantly decreased (p < 0.05), while the expression level of Caspase3 was up-regulated in some different degrees. In addition,The expression levels of liver iNOS and COX2 were significantly increased after the injection of five immunopotentiators (p < 0.05), and the mRNA levels of IFN-α, IFN-ß, IL-1ß, RIG-I, TLR3 and TLR7 genes were also significantly up-regulated compared with the control group (p < 0.05). In conclusion, chlorogenic acid, ß-D-glucan, astragalus flavone, CpG-DNA and chicken IgG can be used as immunopotentiators to regulate duck innate immunity. This study provides a new way to prevent important infectious diseases of ducks, and also provides a certain reference for the application of antibiotic substitutes in animal production.

Transcriptome analyses of potential regulators of pre- and post-ovulatory follicles in the pigeon (Columba livia).

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 4.73million (96% of the raw data) high-quality clean reads, which could be aligned with 20282 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.

Molecular cloning, tissue distribution and function analysis of duck TLR7.

Toll-like receptors (TLRs) play an important role in detecting pathogen-associated molecular patterns (PAMPs). Among the TLRs, TLR7 is involved in the recognition of antiviral compounds and single-stranded RNA. This study was designed to explore the structure and function of TLR7 in duck (Anas platyrhynchos), a natural host for avian influenza virus. Firstly, the full-length cDNA of Shaoxing egg-laying duck TLR7 (duTLR7) was obtained using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). It consisted of 38 base pairs (bp) 5'-untranslated region (UTR), 187 bp 3'-UTR, and 3270 bp open reading frame that encodes a single protein of 1089 amino acid residues. DuTLR7 shares high identity with TLR7 genes from other vertebrates. In healthy ducks, duTLR7 transcripts were broadly expressed in different tissues, with higher expression levels in the liver, kidney, and thymus. The highest relative transcript level of duTLR7 could be induced with R848 stimulation. In addition, overexpression of duTLR7 by stimulating with poly(I:C) significantly promoted IFN-ß, NF-κB, IRF7, TRIF, Mx, STAT1 and STAT2 expressions. Taken together, these results suggest that TLR7 may play an important role in the innate immune response of ducks.

Postharvest factors affect under-skin browning in 'Honey Gold' mango fruit.

BACKGROUND: Under-Skin Browning (USB) is a physiological skin disorder that significantly reduces quality of 'Honey Gold' mango (HG) fruit. Relationships between potential causative factors (vibration, holding temperature, sap) and expression factors (enzymes activities, phenolic concentration, anatomy) were investigated. RESULTS: USB incidence was 2.6-3.6-fold higher in ripe HG fruit vibrated for 3-18 h at 12 °C to simulate transport damage and held then at 12 °C for 8 days compared to control fruit held under the same conditions. USB severity of fruit lightly abraded with sand paper to simulate physical damage and artificially induce USB was higher in fruit held at 10 °C than at 6-8 °C or 12-13 °C for 6-8 days. Compared to non-affected skin, USB-affected tissue had a 7.4% increase in total phenolics concentration. However, polyphenol oxidase (PPO) and peroxidase (POD) activities decreased by 19%. Anatomical similarities were observed between USB symptoms and sapburn caused by spurt sap or terpinolene (a major sap component) to abraded skin areas. Incidence of sapburn was higher in abraded fruit held at 12 °C than at 20 °C. CONCLUSION: Holding HG mango fruit at 10 °C can intensify USB. Activities of PPO and POD appear not to be regulatory factors in USB expression in HG. Sap components may be involved in USB expression under conducive postharvest conditions. © 2021 Society of Chemical Industry.

Graphene oxide enters the rice roots and disturbs the endophytic bacterial communities.

The environmental release of graphene oxide (GO) will certainly induce the GO exposure to plants. To date, the influence of GO on the intracellular structures and the endophytic bacterial ecology of plants have been rarely reported. In the present study, the rice seedlings were exposed to GO (5 mg/L) under hydroponic condition for fifteen days with periodic stir. The cellular structures damage, GO deposition and oxidative stress were found in rice root after GO exposure. A Illumina analysis based on the bacterial 16 S rRNA gene showed that the richness, evenness and diversity of endophytic bacterial communities of rice root decreased due to GO exposure. The relative abundance of beneficial endophytic bacterial populations decreased after GO exposure. Out of potential phenotypes predicted by BugBase, the relative abundance of Gram negative, stress-tolerant and biofilm-forming phenotypes, presented an increase trend after GO exposure.

Effects of cage and floor rearing system on the factors of antioxidant defense and inflammatory injury in laying ducks.

BACKGROUND: Cage-rearing in laying ducks, as a novel rearing system, not only fundamentally solves the pollution problem of the duck industry and improve bio-safety and product quality but also exhibits more benefits by implementing standardized production compared with the floor-rearing. Of course, this system also brings some welfare problems and stress injuries to layers due to lack of water environment and limited activities in the cages. However, the effects on the factors of antioxidant defense and inflammatory injury in the early cage stage are not well-understood. RESULTS: In this study, eighty Shaoxing layers were reared on floor and in cages from 12 weeks of age. The ducks were caged 1, 2, 4, 7, and 10 days, the factors of antioxidant defense and inflammatory injury were investigated. The results showed that the caged ducks suffered liver injury to a certain extent when the ducks were just put into the cages. Analysis of antioxidant enzyme activities indicated that the different rearing system could not affect the change of antioxidant capacities, while the liver malondialdehyde (MDA) level was significant higher in the 2-d, 7-d, and 10-d ducks compared with the 1-d ducks during the change of days, while catalase (CAT) activity showed the opposite results. Additionally, quantitative real-time PCR (qRT-RCR) revealed that the relative mRNA levels of endoplasmic reticulum (ER) stress-related gene (CHOP and GRP78) were significantly upregulated in cage rearing ducks compared to that of the floor rearing ducks. Moreover, the mRNA levels of inflammatory cytokines including cycloxygenase-2 (COX-2), nitric oxide synthase (iNOS), Interleukin 1 beta (IL-1ß), Interleukin 2 (IL-2) and Interleukin 6 (IL-6), were also increased significantly in caged layers. CONCLUSIONS: Taken together, although antioxidant defense has no obvious effect on cage stress, the stress levels of laying ducks vary greatly in the early cage stage, which not only caused liver tissue damage to some extent, but also resulted in increases in the expression of the factors of inflammatory injury. Therefore, we recommend that anti-stress agents should be added in the feed to alleviate the stress in the early cage stage.

MiR-144 affects fatty acid composition by regulating ELOVL6 expression in duck hepatocytes.

Lipid metabolism in duck is very important for both raisers and people's health. In our previous studies, we have detected that miR-144 is related to duck lipid metabolism and validated one of its target genes, elongation of very long chain fatty acids protein 6 (ELOVL6). In the present study, we isolated, cultured, and identified duck hepatocytes, and transfected with miR-144 mimics/inhibitor to mediate the miR-144 level. The qRT-PCR results showed that the ELOVL6 expression in duck hepatocytes was down/upregulated, respectively. The fat contents and each fatty-acid percent content of the hepatocytes and medium were also determined. When ELOVL6 expression suppressed (miR-144 mimics transfected), the palmitic acid (C16:0) content was significantly increased (P < 0.05); the oleic acid (C18:1, n-9), eicosenoic acid (C20:1, n-9), and eicosatrienoic acid (C20:3) contents were significantly reduced (P < 0.05). The myristic acid (C14:0) and palmitic acid (C16:0) contents were significantly reduced (P < 0.05), and the oleic acid (C18:1, n-9) content was significantly increased (P < 0.05) when ELOVL6 expression upregulated (miR-144 inhibitor transfected). It indicated that miR-144 could regulate some saturated fatty acids elongated to longer unsaturated fatty acids through controlling ELOVL6 expression. Whereas, miR-144/ELOVL6 appeared not associated with fat deposition in duck hepatocytes (P > 0.05). Our findings suggest that miR-144 might regulate the percentages of fatty acids in duck hepatocytes through affecting ELOVL6 expression.

Evaluations of diffusion tensor image registration based on fiber tractography.

BACKGROUND: Diffusion Tensor Magnetic Resonance Imaging (DT-MRI, also known as DTI) measures the diffusion properties of water molecules in tissues and to date is one of the main techniques that can effectively study the microstructures of the brain in vivo. Presently, evaluation of DTI registration techniques is still in an initial stage of development. METHODS AND RESULTS: In this paper, six well-known open source DTI registration algorithms: Elastic, Rigid, Affine, DTI-TK, FSL and SyN were applied on 11 subjects from an open-access dataset, among which one was randomly chosen as the template. Eight different fiber bundles of 10 subjects and the template were obtained by drawing regions of interest (ROIs) around various structures using deterministic streamline tractography. The performances of the registration algorithms were evaluated by computing the distances and intersection angles between fiber tracts, as well as the fractional anisotropy (FA) profiles along the fiber tracts. Also, the mean squared error (MSE) and the residual MSE (RMSE) of fibers originating from the registered subjects and the template were calculated to assess the registration algorithm. Twenty-seven different fiber bundles of the 10 subjects and template were obtained by drawing ROIs around various structures using probabilistic tractography. The performances of registration algorithms on this second tractography method were evaluated by computing the spatial correlation similarity of the fibers between subjects as well as between each subject and the template. CONCLUSION: All experimental results indicated that DTI-TK performed the best under the study conditions, and SyN ranked just behind it.

Transcriptomic analysis of different stages of pigeon ovaries by RNA-sequencing.

The pigeon ovary is an ideal model for deciphering the molecular mechanism of folliculogenesis. While most analysis has focused on the influence of hormones and factors on ovarian follicle development in this model, changes occurring in the ovarian stroma can also be extremely informative. Here, we profiled the transcriptome of pigeon ovaries at pre-ovulation, post-ovulation, and 5-6 days after ovulation using RNA-sequencing to gain insights into the molecular and cellular events mediating ovary activity. We obtained 44,784,505 clean reads that aligned with 14,088 genes. Gene expression profile analysis identified 409 differentially expressed genes between pre- and post-ovulation; 96 genes were up-regulated genes while 313 genes were down-regulated. Gene ontology analysis of the down-regulated genes revealed significant enrichment in components of the immune response, immune system, antigen processing and presentation, receptor binding, and biological adhesion. Pathway analyses of the high-expression genes of the post-ovulation ovary identified enrichment in phagosomes, lysosomes, cytokine-cytokine receptor interactions, cell adhesion molecules, and the Toll-like receptor signaling. These data together suggest that post-ovulatory follicle regression and elimination occurs through an immune response. Mol. Reprod. Dev. 83: 640-648, 2016. © 2016 Wiley Periodicals, Inc.

Efficacy evaluation of summer acupoint application treatment on asthma patients: a two-year follow-up clinical study.

UNLABELLED: fill out a questionnaire evaluating asthma degree, exacerbation frequency, concomitant medications and self-satisfaction. The self-rate and doctor-report outcomes obtained in parallel were evaluated to assess the efficacy of SAAT. RESULTS: A total of 527 asthma patients were initially enrolled in this study, of which 97 elderly patients and those with more severe cases of asthma were lost to follow-up. Thus, a total of 430 patients were valid for analysis using self-rate data. Nevertheless, occasional negative returns were obtained; almost all of the outcomes were rated as "No change", "Moderate effective", or "Very effective". In addition, 80% of the patients were satisfied with this treatment. Moreover, 391 (91.4% ) patients were somewhat improved after SAAT in 2009, and further improvement was observed in 2010. After SAAT, the average asthma-degree score decreased from 5.3 in 2008 to 4 in 2009 and, subsequently to 3.5 in 2010. CONCLUSION: With pronounced patient satisfaction, SAAT can reduce the exacerbation severity and frequency, concomitant medications and asthma degree. Prolonging the treatment course might enhance the efficacy of SAAT. OBJECTIVE: To evaluate the self-efficacy and satisfaction of asthma patients subjected to summer acupoint application treatment (SAAT). METHODS: A two-year follow-up clinical study was conducted. Patients with asthma were treated by applying a herbal paste onto the Feishu (BL 13) and Fengmen (BL 12) acupoints on the three hottest days of summer, according to the traditional Chinese calendar, from 2008 to 2010. During a two-year follow-up, these patients were asked to

[Evaluation for Merchandise Character and Quality of Bupleurum chinense Root from Different Habitats].

OBJECTIVE: To evaluate the merchandise character and quality of Bupleurum chinense root from different habitats. METHODS: The spectrophotometer method was used to determine the content of total saponins and total flavonoids in Bupleurum chinense root. The content of alcohol-soluble extract and total ash were determined according to the method in the Chinese Pharmacopoeia. RESULTS: The quality of Bupleuri Radix from different habitats varied greatly. There were also differences (P < 0.05) between the merchandise packaged with selection and the merchandise packaged without selection of Bupleurum chinense root from the same habitats. The merchandise packaged without selection had the better quality, whose root length, root diameter, weight, total length proportional share of residual stems, total saponins, total flavonoids, total alcohol-soluble extract and total ash was 14.50 cm/plant, 0.59 cm/plant, 5.14 g/plant, 36.85%, 0.721%, 0.615%, 12.993% and 4.890%, respectively. CONCLUSION: Bupleurum chinense root from Tong'an, Jiangsu has the best quality in the test samples from different habitats.

Effects of coated sodium butyrate on the growth performance, serum biochemistry, antioxidant capacity, intestinal morphology, and intestinal microbiota of broiler chickens.

Introduction: This study examined the impact of adding coated sodium butyrate (CSB) to the diet on the growth performance, serum biochemistry, antioxidant capacity, intestinal morphology, and cecal microbiota of yellow-feathered broiler chickens. Methods: In this study, 240 yellow-feathered broiler chickens at 26 days old were divided into two groups: the control group (CON group) received a standard diet, and the experimental group (CSB group) received a diet with 0.5 g/kg of a supplement called CSB. Each group had 6 replicates, with 20 chickens in each replicate, and the experiment lasted for 36 days. Results: Compared to the CON group, the CSB group showed a slight but insignificant increase in average daily weight gain during the 26-62 day period, while feed intake significantly decreased. The CSB group exhibited significant increases in serum superoxide dismutase, catalase, and total antioxidant capacity. Additionally, the CSB group had significant increases in total protein and albumin content, as well as a significant decrease in blood ammonia levels. Compared to the CON group, the CSB group had significantly increased small intestine villus height and significantly decreased jejunal crypt depth. The abundance of Bacteroidetes and Bacteroides in the cecal microbiota of the CSB group was significantly higher than that of the CON group, while the abundance of Proteobacteria, Deferribacteres, and Epsilonbacteraeota was significantly lower than that of the CON group. Conclusion: These results suggest that adding CSB to the diet can improve the growth performance and antioxidant capacity of yellow-feathered broiler chickens while maintaining intestinal health.

Integrated transcriptome and microbiome analyses of residual feed intake in ducks during high production period.

Residual feed intake (RFI) is a crucial parameter for assessing the feeding efficiency of poultry. Minimizing RFI can enhance feed utilization and reduce costs. In this study, 315 healthy female ducks were individually housed in cages. Growth performance was monitored during the high laying period, from 290 to 325 d of age. The cecal transcriptome and microbiome of 12 ducks with high RFI and 12 with low residual feed intake (LRFI) were analyzed. Regarding growth performance, the LRFI group exhibited significantly lower RFI, feed conversion ratio (FCR), and feed intake (Fi) compared to the HRFI group (p < 0.01). However, there were no significant differences observed in body weight (BW), body weight gain (BWG), and egg mass (EML) between the groups (p > 0.05). Microbiome analysis demonstrated that RFI impacted gut microbial abundance, particularly affecting metabolism and disease-related microorganisms such as Romboutsia, Enterococcus, and Megamonas funiformis. Transcriptome analysis revealed that varying RFI changed the expression of genes related to glucose metabolism and lipid metabolism, including APOA1, G6PC1, PCK1, and PLIN1. The integrated analysis indicated that host genes were closely linked to the microbiota and primarily function in lipid metabolism, which may enhance feeding efficiency by influencing metabolism and maintaining gut homeostasis.

[Treating influenza patients of wind-heat affecting Fei syndrome by jinhua qinggan granule: a double-blinded randomized control trial].

OBJECTIVE: To assess the effect and safety of Jinhua Qinggan Granule (JHG) in treating influenza patients of wind-heat affecting Fei syndrome (WHAFS). METHODS: Totally 136 influenza patients of WHAFS were randomized by stratification into 3 groups, the high dose JHG group (44 cases, 10 g each time), the low dose JHG group (45 cases, 5 g JHG + 5 g placebo each time), and the placebo control group (47 cases, 10 g placebo each time). All medication was administered three times daily for 5 days. The fever disappearance time, the fever disappearance rate, efficacy of TCM syndrome, the disappearance rate of main symptoms and physical signs of flu, the negative rate of virus nucleic acid in the pharyngeal secretion, and safety indicators were assessed. RESULTS: The median fever disappearance time was 32.8 h (95% CI: 22.5-41.0 h) in the high dose JHG group, 26.0 h (95% CI: 14.5-36.5 h) in the low dose JHG group, 39.5 h (95% CI: 29.0-46.0 h) in the placebo control group. There was statistical difference in the median fever disappearance time between the low dose JHG group and the placebo control group (P = 0.011). Three days after treatment, the markedly effective rate of TCM symptoms in the low dose JHG group was 66.7%, higher than that of the placebo control group (38.3%), and its effective rate was superior to that of the high dose JHG group (P = 0.043). Five days after treatment, the recovery rate of the low dose JHG group (42.2%) was higher than that of the high dose JHG group (25.0%, P = 0.026) and that of the placebo control group (14.9%, P = 0.002). The markedly effective rate of the low dose JHG group (86.7%) was higher than that of the placebo control group (55.3%, P = 0.001). Similar effects were obtained in the low dose JHG group and the high dose JHG group, but slightly poor in partial indicators of the high dose JHG group. There was no statistical difference in adverse reaction among these three groups (P > 0.05). CONCLUSIONS: JHG was effective and safe in treating influenza patients of WHAFS. Routinely low dose was the optimal dosage of JHG.

Optimization of the Process for Green Jujube Vinegar and Organic Acid and Volatile Compound Analysis during Brewing.

Healthy fruit vinegar has become very popular recently in China. This study aimed to produce fruit vinegar with a good taste, high nutritional value, and strong functional properties from green jujube. This study investigated the optimization of the process for green jujube vinegar using response surface methodology. The optimum fermentation parameters for green jujube vinegar were determined as follows: initial alcoholicity 6%, acetobacter 8%, fermentation temperature 32 °C, and time 7 d. The organic acids of the optimized sample were evaluated by HPLC, and the volatile substances were identified and analyzed by HS-SPME and GC-MS during the fermentation and aging of the green jujube vinegar. The results showed that the variation trends of the different organic acids during the making of the green jujube vinegar were significantly different. Organic acids are the key flavor compounds of green jujube vinegar, and their changes were mainly attributed to microbial metabolism. In particular, the green jujube vinegar stood out in terms of volatile aroma compounds, including a total of 61 volatile compounds whose major components were acetic acid, isoamyl acetate, ethyl acetate, 3-hydroxy-2-butanone, methyl palmitate, and ethanol. The results can provide theoretical support for the production of green jujube vinegar.

Use of different food additives to control browning in fresh-cut potatoes.

Fresh-cut potato browning is a severe problem in the potato processing industry. Ascorbic acid, L-cysteine, hydrogen sulfide (H2S), and nitric oxide (NO) have been reported to reduce the browning in fresh-cut vegetables and fruits. We compared the effect of each food additive at its commonly used concentration on fresh-cut potato browning in order to choose a highly efficient treatment and explore its mechanism. Fresh-cut potato slices were immersed in 0.3 mmol L-1 ascorbic acid, 0.7 mmol L-1 L-cysteine, 0.7 mmol L-1 H2S, or 2.0 mmol L-1 NO for 10 min and stored at 4°C until the measurements finished. Results showed that the ascorbic acid and L-cysteine treatments showed less browning than the control treatment, while the H2S and NO treatments did not. Ascorbic acid increased total phenolic content, polyphenol oxidase (PPO) and peroxidase (POD) activities, while L-cysteine decreased PPO and POD activities with no change in total phenolic content. In addition, these two treatments did not influence respiration rate, weight loss, or rot index. In conclusion, ascorbic acid (0.3 mmol L-1) and L-cysteine (0.7 mmol L-1) can be valuable means to control fresh-cut potato browning. Ascorbic acid inhibits the browning mainly by reducing quinones back to phenolic compounds, but L-cysteine inhibits the browning mainly by decreasing PPO and POD activities.

Integration of LC-MS-Based and GC-MS-Based Metabolic Profiling to Reveal the Effects of Domestication and Boiling on the Composition of Duck Egg Yolks.

Egg yolks contain abundant lipids, proteins, and minerals that provide not only essential nutrients for embryonic development but also cheap sources of nutrients for consumers worldwide. Previous composition analyses of egg yolks primarily focused on nutrients such as lipids and minerals. However, few studies have reported the effects of domestication and heating on yolk composition and characteristics. The objective of this study was to investigate the impact of domestication and boiling on the metabolite contents of egg yolks via untargeted metabolomics using GC-MS and LC-MS. In this study, eggs were collected from Fenghua teals, captive mallards, and Shaoxing ducks. Twelve duck eggs (half raw and half cooked) were randomly selected from each variety, and the egg yolks were separated for metabolic profiling. The analysis identified 1205 compounds in the egg yolks. Domestication generated more differential metabolites than boiling, which indicated that the changes in the metabolome of duck egg yolk caused by domestication were greater than those caused by boiling. In a comparative analysis of domestic and mallard ducks, 48 overlapping differential metabolites were discovered. Among them, nine metabolites were upregulated in domesticated ducks, including monoolein, emodin, daidzein, genistein, and glycitein, which may be involved in lipid metabolism; some of them may also act as phytoestrogens (flavonoids). Another 39 metabolites, including imethylethanolamine, harmalan, mannitol, nornicotine, linoleic acid, diphenylamine, proline betaine, alloxanthin, and resolvin d1, were downregulated by domestication and were linked to immunity, anti-inflammatory, antibacterial, and antioxidant properties. Furthermore, four overlapping differential metabolites that included amino acids and dipeptides were discovered in paired comparisons of the raw and boiled samples. Our findings provided new insights into the molecular response of duck domestication and supported the use of metabolomics to examine the impact of boiling on the composition of egg yolks.

Association of residual feed intake with intestinal microbiome and metabolome in laying period of ducks.

Introduction: Residual feed intake (RFI) is a indicator to evaluate animal feed. This experiment was explored to study the relationship between intestinal microbiome and metabolome of ducks with different residual feed intake during laying period. Methods: A total of 300 Shaoxing ducks aged 42 weeks were randomly selected and fed a diet of 60 d. At the end of the trial, 20 samples were selected according to the phenotype of RFI and divided into two groups (HRFI and LRFI). The cecal microbiota composition was explored by 16S ribosomal RNA gene sequencing and rectal metabolomics uses liquid chromatography-mass spectrometry (LC-MS) to identify the composition of metabolites in a non-targeted manner. Results: Results show feed intake and feed conversion ratio in the group HRFI were significantly higher than those in the group LRFI (p < 0.05). Chao1 indices were higher in the group LRFI than in the HRFI (p < 0.05), Shannon and Simpson indices were higher in the group LRFI than in the HRFI (p < 0.01). After linear discriminant analysis effect size (p < 0.05, LDA score > 3), Rikenellaceae, Rikenellaceae_RC9_gut_group, Lactobacillales and Ruminococcus_2, etc. were significantly enriched in the group LRFI at the genus level, while Prevotellaceae_NK3B31_group and Bacteria were significantly enriched in the group HRFI. After LC-MS analysis we found 338 metabolic difference products and 10 metabolic pathways, including the ABC transporter system, cysteine and methionine metabolism, arginine and proline metabolism, and vitamin B6 metabolism, were identified to be associated with the significantly differentially expressed between the groups LRFI and HRFI (p < 0.05). We hypothesize that the difference between ducks with different RFIs is mainly due to the fact that ducks with LRFI have more SCFAs-producing bacteria in their gut microorganisms, which regulate the RFI of animals. This process we found that Phascolarctobaterium and Anaerobiospirillum may provide energy for ABC transporter system by producing SCFAs, and regulate RFI to improve feed utilization efficiency. Discussion: These results revealed the relationship between microbiome and metabonomics in laying ducks with different RFI, and provided theoretical basis for further study on the relationship between them.

Dietary supplementation of coated sodium butyrate improves growth performance of laying ducks by regulating intestinal health and immunological performance.

Introduction: This study was conducted to assess the effects of dietary supplementation of coated sodium butyrate (CSB) on the growth performance, serum antioxidant, immune performance, and intestinal microbiota of laying ducks. Methods: A total of 120 48-week-old laying ducks were randomly divided into 2 treatment groups: the control group (group C fed a basal diet) and the CSB-treated group (group CSB fed the basal diet + 250 g/t of CSB). Each treatment consisted of 6 replicates, with 10 ducks per replicate, and the trial was conducted for 60 days. Results: Compared with the group C, the group CSB showed a significant increase in the laying rate (p<0.05) of the 53-56 week-old ducks. Additionally, the serum total antioxidant capacity, superoxide dismutase activity and immunoglobulin G level were significantly higher (p<0.05), while the serum malondialdehyde content and tumor necrosis factor (TNF)-a level were significantly lower (p<0.05) in the serum of the group CSB compared to the group C. Moreover, the expression of IL-1b and TNF-a in the spleen of the group CSB was significantly lower (p<0.05) compared to that of the group C. In addition, compared with the group C, the expression of Occludin in the ileum and the villus height in the jejunum were significantly higher in the group CSB (p<0.05). Furthermore, Chao1, Shannon, and Pielou-e indices were higher in the group CSB compared to the group C (p<0.05). The abundance of Bacteroidetes in the group CSB was lower than that in the group C (p<0.05), while the abundances of Firmicutes and Actinobacteria were higher in the group CSB compared to the group C (p<0.05). Conclusions: Our results suggest that the dietary supplementation of CSB can alleviate egg-laying stress in laying ducks by enhancing immunity and maintaining the intestinal health of the ducks.