Effects of thiram exposure on liver metabolism of chickens.

Pesticides are widely used to control crop diseases, which have made an important contribution to the increase of global crop production. However, a considerable part of pesticides may remain in plants, posing a huge threat to animal safety. Thiram is a common pesticide and has been proven that its residues in the feed can affect the growth performance, bone formation, and intestinal health of chickens. However, there are few studies on the liver metabolism of chickens exposed to thiram. Here, the present study was conducted to investigate the effect of thiram exposure on liver metabolism of chickens. Metabolomics analysis shows that 62 metabolites were down-regulated (ginsenoside F5, arbekacin, coproporphyrinogen III, 3-keto Fusidic acid, marmesin, isofumonisin B1, 3-Hydroxyquinine, melleolide B, naphazoline, marmesin, dibenzyl ether, etc.) and 35 metabolites were up-regulated (tetrabromodiphenyl ethers, deoxycholic acid glycine conjugate, L-Palmitoylcarnitine, austalide K, hericene B, pentadecanoylcarnitine, glyceryl palmitostearate, quinestrol, 7-Ketocholesterol, tetrabromodiphenyl ethers, etc.) in thiram-induced chickens, mainly involved in the metabolic pathways including glycosylphosphatidylinositol (GPI)-anchor biosynthesis, porphyrin and chlorophyll metabolism, glycerophospholipid metabolism, primary bile acid biosynthesis and steroid hormone biosynthesis. Taken together, this research showed that thiram exposure significantly altered hepatic metabolism in chickens. Moreover, this study also provided a basis for regulating the use and disposal of thiram to ensure environmental quality and poultry health.

Genome-wide association studies and haplotype sharing analysis targeting the growth traits in Yandang partridge chickens.

The body size of a chicken is an economically important trait as it directly influences the benefits of the poultry industry, but the relevant genetic mechanisms have not yet been elucidated. In this study, we measured eight growth traits for 94 Yandang partridge chickens, then undertook genome-wide association studies (GWAS) for those traits in using a linear mixed model based on 10× whole genomic sequencing data to better understand the knowledge of the genetic architecture of growth traits. Ninety-four individuals and 7647883 SNPs remained after quality control and removal of the sex chromosomes, and these data were used to carry out a GWAS analysis. The result showed that only one significant single-nucleotide polymorphisms (SNP) locates at 14852873 bp on SSC13 surpassed the genome-wide significance level for Keel length (KL). Through linkage disequilibrium analysis and haplotype sharing analysis, we identified one haplotype underlying the SSC13 significantly associated with KL, which could be selected as a potential candidate haplotype that is used in molecular breeding of Yandang partridge chicken. On the other hand, we have learned from a method called bootstrap testing to verify the reliability of GWAS with small experimental samples, which users can access at https://github.com/xuwenwu24/Bootstrap-test.

Genome-Wide Association Study of Egg-Laying Traits and Egg Quality in LingKun Chickens.

Egg production is the most important trait of laying hens. To identify molecular markers and candidate genes associated with egg production and quality, such as body weight at first oviposition (BWF), the number of eggs produced in 500 days (EN500), egg weight (EW), egg shell thickness (EST), egg shell strength (ESS), and Haugh unit (HU), a genome-wide analysis was performed in 266 LingKun Chickens. The results showed that thirty-seven single nucleotide polymorphisms (SNPs) were associated with all traits (p < 9.47 × 10-8, Bonferroni correction). These SNPs were located in close proximity to or within the sequence of the thirteen candidate genes, such as Galanin And GMAP Prepropeptide (GAL), Centromere Protein (CENPF), Glypican 2 (GPC2), Phosphatidylethanolamine N-Methyltransferase (PEMT), Transcription Factor AP-2 Delta (TFAP2D), and Carboxypeptidase Q (CPQ) gene related to egg-laying and Solute Carrier Family 5 Member 7 (SLC5A7), Neurocalcin Delta (NCALD), Proteasome 20S Subunit Beta 2 (PSMB2), Slit Guidance Ligand 3 (SLIT3), and Tubulin Tyrosine Ligase Like 7 (TTLL7) genes related to egg quality. Interestingly, one of the genes involved in bone formation (SLIT3) was identified as a candidate gene for ESS. Our candidate genes and SNPs associated with egg-laying traits were significant for molecular breeding of egg-laying traits and egg quality in LingKun chickens.

Effects of Hydroxylated Lecithin on Growth Performance, Serum Enzyme Activity, Hormone Levels Related to Lipid Metabolism and Meat Quality in Jiangnan White Goslings.

The objective of the present study was to evaluate the effects of hydroxylated lecithin on growth performance, serum enzyme activity, hormone levels related to lipid metabolism and meat quality in Jiangnan White goslings. Six hundred 1-day-old goslings were randomly divided into five treatments with six replicates and 20 for each replicate. The control group (CG) was fed the basal diet, while the experimental group was fed the basal diet with 50, 100, 200 mg/kg hydroxylated lecithin and 100 mg/kg soy lecithin (HLG50, HLG100, HLG200, and LG100, respectively) in the form of powder. Feed and water were provided ad libitum for 32 days. Compared with the CG, (a) the average daily feed intake was higher (P < 0.05) in HLG100, the final body weight and average daily gain were higher (P < 0.05), and the feed conversion ratio was lower in the HLG200; (b) the alanine aminotransferase, malate dehydrogenase, leptin, glucagon, thyroid hormone, Triiodothyronine contents in the HLG200 were lower (P < 0.05); (c) The breast muscle water holding capacity was higher (P < 0.05) in groups with hydroxylated lecithin, the breast muscle shear force and fiber diameter were lower (P < 0.05) in the HLG100; (d) the inositic acid, intramuscular fat, phospholipid contents were higher (P < 0.05), the triglyceride content was lower (P < 0.05) in HLG100 of the breast muscle; (e) the relative expression of sterol regulatory element-binding protein-1 genes were higher (P < 0.05) in the treated groups of muscles, the phosphorylase kinase gamma subunit 1 gene expression was shown an opposite trend. In comparison with LG100, (a) the feed conversion ratio was lower (P < 0.05) in HLG200; (b) the alanine aminotransferase and adiponectin contents were higher (P < 0.05), the malondialdehyde and free fatty acid contents were lower (P < 0.05) in HLG200; (c) the water holding capacity and intramuscular fat contents in the breast and leg muscles were higher (P < 0.05) in HLG200. The hydroxylated lecithin concentration of 200 mg/kg improved the growth performance, serum enzyme activity, hormone levels related to lipid metabolism, and the meat quality of Jiangnan White goslings.

Two DsbA Proteins Are Important for Vibrio parahaemolyticus Pathogenesis.

Bacterial pathogens maintain disulfide bonds for protein stability and functions that are required for pathogenesis. Vibrio parahaemolyticus is a Gram-negative pathogen that causes food-borne gastroenteritis and is also an important opportunistic pathogen of aquatic animals. Two genes encoding the disulfide bond formation protein A, DsbA, are predicted to be encoded in the V. parahaemolyticus genome. DsbA plays an important role in Vibrio cholerae virulence but its role in V. parahaemolyticus is largely unknown. In this study, the activities and functions of the two V. parahaemolyticus DsbA proteins were characterized. The DsbAs affected virulence factor expression at the post-translational level. The protein levels of adhesion factor VpadF (VP1767) and the thermostable direct hemolysin (TDH) were significantly reduced in the dsbA deletion mutants. V. parahaemolyticus lacking dsbA also showed reduced attachment to Caco-2 cells, decreased ß-hemolytic activity, and less toxicity to both zebrafish and HeLa cells. Our findings demonstrate that DsbAs contribute to V. parahaemolyticus pathogenesis.

Protective role of dryland rearing on netting floors against mortality through gut microbiota-associated immune performance in Shaoxing ducks.

Dryland rearing on netting floors (DRNF) is a new rearing method for ducks, which could prevent duck excreta from polluting water bodies. However, the influence of DRNF on duck production and immune performance remains poorly understood. In this study, 2,280 Shaoxing ducks, an egg-type breed of Sheldrake in China, were chosen and randomly divided into 2 groups to investigate the effects of DRNF on duck farming. During the experimental laying rates, feed-egg ratios, and mortality rates of the 2 groups were calculated and recorded. Serum immune parameters, including thymus index, spleen index, levels of immunoglobulin G (IgG), interleukin 1ß (IL-1ß), and tumor necrosis factor α (TNF-α), were determined. Sequencing of the 16S rRNA gene was used to analyze the variability of gut microbiota in the duck ileum and cecum. The results showed that DRNF significantly reduced the mortality rate of the ducks and increased the thymus index (P < 0.05), compared to the control. No other significant differences were detected in productional and immune indices (P > 0.05). The 16S rRNA sequencing results revealed differentially enriched microbial compositions in the ileum and cecum, which might be responsible for the improved immune function of Shaoxing ducks. For example, an increase in Lactobacillaceae (family), Anaerotruncus (genus), Saccharibacteria (phylum), Flavobacteriaceae (family), and a reduction in Anaerobiospirillum (genus), Lachnospiraceae (family), Blautia (genus) was revealed in the DRNF ducks. In conclusion, DRNF could alter gut microflora, enhance duck immune system, and reduce mortality in Shaoxing ducks.

Redox pathway sensing bile salts activates virulence gene expression in Vibrio cholerae.

Vibrio cholerae, the causative agent of the severe diarrheal disease cholera, has evolved signal transduction systems to control co-ordinately the expression of virulence determinants. It was previously shown that the presence of the bile salts glycocholate and taurocholate in the small intestine causes dimerization of the transmembrane transcription factor TcpP by inducing intermolecular disulphide bonds in the TcpP periplasmic domain. In this study, they further investigated the mechanism of how taurocholate affects V. cholerae virulence determinants. In vitro assay of TcpP oxidation by VcDsbA showed that VcDsbA induced TcpP dimerization in the presence of taurocholate. Taurocholate bound to VcDsbA with a KD of 40 ± 2.5 µM, and also bound other Dsb proteins, including EcDsbA, EcDsbC and VcDsbC. Taurocholate inhibited VcDsbA reductase activity without affecting VcDsbA secondary structure or thermostability. VcDsbA and its substrates were more extensively reduced in the presence of taurocholate, as compared with their redox state in the absence of taurocholate. The data presented here not only provide new insights into the mechanism by which bile salts induce V. cholerae virulence but also suggest a means by which to develop inhibitors against DsbA.

[VcDsbA enhances bioflim formation by stimulating MSHA expression in Vibrio cholera].

Objective: Biofilm plays an important role during the infection cycle of Vibrio cholerae. In this study, we try to demonstrate the role of VcDsbA in the biofilm formation of V. cholerae. Methods: By making the VcDsbA inframe knock-out construct, the vcdsbA null mutant (ΔdsbA) strain was obtained. And the complemented strain (CΔdsbA) was constructed by transferring a plasmid-coded VcDsbA expressed under the control of arabinose to ΔdsbA strain. Crystal violet staining assay was used to analyze the biofilm formation in the wild-type (WT), ΔdsbA and CΔdsbA strains. V. cholerae strains containing msh promoter luxCDABE transcriptional fusion were used to analyze the transcriptional level. Results: The ΔdsbA and CΔdsbA strains were constructed successfully. Biofilm formation analysis shows that the ability of biofilm formation of ΔdsbA was significantly reduced compared with WT, whereas CΔdsbA could form even stronger biofilm than WT does. Luminescence expression by Pmsh shows that VcDsbA enhanced msh expression. VcDsbA enhances the biofilm formation of V. cholerae by involving in the regulation of msh expression level. VcDsbA up-regulates msh expression probably through helping the folding of a msh expression activator. Conclusion: VcDsbA plays an important role in the biofilm formation of V. chlerae, which makes the bacteria better survive in their living niche.