ADPN Regulates Oxidative Stress-Induced Follicular Atresia in Geese by Modulating Granulosa Cell Apoptosis and Autophagy.

Geese are susceptible to oxidative stress during reproduction, which can lead to follicular atresia and impact egg production. Follicular atresia is directly triggered by the apoptosis and autophagy of granulosa cells (GCs). Adiponectin (ADPN), which is secreted by adipose tissue, has good antioxidant and anti-apoptotic capacity, but its role in regulating the apoptosis of GCs in geese is unclear. To investigate this, this study examined the levels of oxidative stress, apoptosis, and autophagy in follicular tissues and GCs using RT-qPCR, Western blotting, immunofluorescence, flow cytometry, transcriptomics and other methods. Atretic follicles exhibited high levels of oxidative stress and apoptosis, and autophagic flux was obstructed. Stimulating GCs with H2O2 produced results similar to those of atretic follicles. The effects of ADPN overexpression and knockdown on oxidative stress, apoptosis and autophagy in GCs were investigated. ADPN was found to modulate autophagy and reduced oxidative stress and apoptosis in GCs, in addition to protecting them from H2O2-induced damage. These results may provide a reasonable reference for improving egg-laying performance of geese.

Protective effects of AdipoRon on the liver of Huoyan goose fed a high-fat diet.

Adiponectin can participate in the regulation of glucose and lipid metabolism, energy regulation, immune response, resistance to inflammation, oxidative stress, and apoptosis. Studies in rodents demonstrated that the small molecule compound adiponectin receptor agonist AdipoRon could activate the adiponectin receptor and played the same biological role as adiponectin. To explore the influence and regulation of AdipoRon on lipid metabolism disorder in Huoyan goose liver, in this study, goslings were fed a high-fat diet and then administered different dosages of AdipoRon. Subsequently, goose body weight, liver index, liver histopathological changes, blood glucose, blood and liver lipid, biochemical indexes related to liver function and oxidative stress, and the expression levels of genes related to lipid metabolism, inflammation, apoptosis, and autophagy, adiponectin and its receptors, key molecules of adiponectin involved signal pathway, and transcription factors in the liver, were detected using H&E and Oil red O staining, ELISA, and qRT-PCR methods. The results indicated that AdipoRon could alter the expression of lipid metabolism-related genes, inflammatory factors, apoptosis and autophagy genes, and adiponectin and its receptor genes in liver tissues through signaling pathways such as AMPK and p38 MAPK, as well as the involvement of transcription factors such as PPARα, PPARγ, SIRT1, and FOXO1, reduce the lipid content in blood and liver tissues of geese fed high-fat diets, improve liver antioxidant capacity, regulate apoptosis and autophagy of hepatocytes, and reduce liver inflammatory injury. Our study suggests that AdipoRon has a protective effect on fatty liver injury in goslings fed a high-fat diet.

Antimicrobial resistance analysis and whole-genome sequencing of Salmonella enterica serovar Indiana isolate from ducks.

OBJECTIVES: Salmonella is one of the most important genera of enteric pathogenic bacteria that threaten duck farms. The aim of this study was to increase the understanding of antimicrobial resistance mechanisms in Salmonella enterica serovar Indiana isolates of duck origin. METHODS: Salmonella were isolated from duck cloacal swabs collected from duck farms located in Zhejiang and Henan provinces of China. All of the isolates were identified after a series of confirmatory tests including selective culture method, biochemical tests, serotyping and PCR targeting the invA gene. Isolates were then subjected to antimicrobial susceptibility testing by the standard Kirby-Bauer disk diffusion method. Subsequently, whole-genome sequencing analysis of a representative multidrug-resistant Salmonella Indiana isolate (designated SAP) was performed using a combination of Nanopore and Illumina sequencing platforms. RESULTS: A total of 18 Salmonella isolates were identified. The predominant serotype was Salmonella Indiana (14 of 18 isolates). All 14 Salmonella Indiana isolates were multiresistant to ten antimicrobials with multidrug resistance to ampicillin, cefoperazone, gentamicin, kanamycin, neomycin, tetracycline, norfloxacin, ciprofloxacin, colistin B and trimethoprim/sulfamethoxazole. The genome of Salmonella Indiana isolate SAP carried 65 antimicrobial resistance genes (ARGs) belonging to different families, including genes encoding antibiotic efflux pumps, rpsL, kdpDE, aac(6'), general bacterial porin with reduced permeability to ß-lactams, AmpC-type ß-lactamase gene, mutant lpx gene conferring resistance to colistin, sulfonamide-resistant dihydropteroate synthase folP and trimethoprim-resistant dihydrofolate reductase dfr. CONCLUSION: The Salmonella Indiana strain isolated in this study carried multiple ARGs and exhibited resistance to multiple antibiotics.

Effects of recombinant goose adiponectin on steroid hormone secretion in Huoyan geese ovarian granulosa cells.

Adiponectin is an adipokine associated with the regulation of reproductive processes. To determine whether recombinant goose adiponectin contributes to the goose ovarian steroidogenesis, the native and then purified goose recombinant adiponectin protein was produced using recombinant DNA technologies. The effect of recombinant adiponectin on the progesterone (P4) and estradiol (E2) production in Huoyan geese ovarian granulosa cells was examined. Furthermore, the effect of recombinant adiponectin (2.5 µg/mL) on the abundance of StAR (steroidogenic acute regulatory protein), CYP11A1 (cytochrome P450scc, cholesterol side-chain cleavage enzyme) and CYP19A1 (cytochrome P450 aromatase) mRNA and protein in granulosa cells was evaluated. Results indicate that a 24-h treatment with recombinant adiponectin (2.5 µg/mL) affected P4 and E2 production by geese ovarian granulosa cells by stimulating P4 production (P < 0.01) and weakly inhibiting E2 production (P > 0.05). Furthermore, when the results with treatment were compared to when there was not adiponectin treatment, the abundance of StAR and CYP11A1 mRNA was greater (P < 0.05) while the CYP19A1 mRNA slightly decreased (P > 0.05). In addition, the fluorescence intensity of StAR tended to be greater compared to PBS-treated (P < 0.05) and control groups (P > 0.05) and StAR protein abundance was greater (P < 0.05) compared to the other two groups. The fluorescence intensity and protein abundances of CYP11A1 increased (P < 0.05) while those for CYP19A1 tended to decrease (P > 0.05) after adiponectin treatment. The results indicate recombinant goose adiponectin affects steroidogenesis and/or hormone secretion of geese ovarian granulosa cells. There may, therefore, be important functions of adiponectin in goose reproductive physiology.

Comparative proteomic analysis of hypothalamus tissue from Huoyan geese between pre-laying period and laying period using an iTRAQ-based approach.

The hypothalamus plays a central role in controlling poultry endocrine and reproductive activities. So far there is limited information focused on the proteome profiles of the hypothalamus from geese during different stages of the egg-laying cycle. In order to identify proteins regulating the egg-laying process of Huoyan geese, we investigated the proteome profiles of the hypothalamus from Huoyan geese during the laying period and pre-laying period by applying an isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic technology. A total number of 3,337 were identified and quantified, of which 18 were significantly up-regulated and 16 were significantly down-regulated. These differentially expressed proteins were subjected to bioinformatics analyses based on the Gene Ontology annotation and Kyoto Encyclopedia of Genes and Genomes pathway. Some of these were revealed to be involved in hormone and neurotransmitter secretion, exocytosis, calcium ion transport and synaptic transmission. Subsequently, excitatory amino acid transporter 2, complexin-1 and inositol 1,4,5-trisphosphate receptor, type 3 were confirmed at the messenger RNA level using quantitative real-time RT-PCR. Then, the abundance change of these proteins was verified further using Western blotting analysis. These data may aid in elucidating the molecular mechanism of higher laying performance in Huoyan geese.

Comparative proteomic analysis of pituitary glands from Huoyan geese between pre-laying and laying periods using an iTRAQ-based approach.

In this study, we performed a comprehensive evaluation of the proteomic profile of the pituitary gland of the Huoyan goose during the laying period compared to the pre-laying period using an iTRAQ-based approach. Protein samples were prepared from pituitary gland tissues of nine pre-laying period and nine laying period geese. Then the protein samples from three randomly selected geese within each period were pooled in equal amounts to generate one biological sample pool. We identified 684 differentially expressed proteins, including 418 up-regulated and 266 down-regulated proteins. GO annotation and KEGG pathway analyses of these proteins were conducted. Some of these proteins were found to be associated with hormone and neurotransmitter secretion and transport, neuropeptide signalling and GnRH signalling pathways, among others. Subsequently, the modification of the abundance of three proteins (prolactin, chromogranin-A and ITPR3) was verified using western blotting. Our results will provide a new source for mining genes and gene products related to the egg-laying performance of Huoyan geese, and may provide important information for the conservation and utilization of local goose breeds.

Molecular cloning and expression analysis of neuregulin 1 (Nrg1) in the hypothalamus of Huoyan goose during different stages of the egg-laying cycle.

Neuregulin 1 (Nrg1) is one of the most active members of the epidermal growth factor (EGF)-like family, which bind to the ErbB tyrosine kinase receptor and play many roles in modulation of synaptic activity, synaptogenesis, GABAergic neurotransmission, neurotransmitter receptor expression and the hormonal control of neuroendocrine reproductive development. In this study, we cloned and characterized the cDNA of goose Nrg1 originating from hypothalamus tissues of Huoyan goose using RACE method, investigated the mRNA expression profiles during different stages of the egg-laying cycle by real-time PCR. Multiple alignments and phylogenetic analyses of the deduced amino acid sequence were conducted using bioinformatics tools. We also determined the profiles of blood serum progesterone, estradiol, FSH and LH content during different egg-laying stages using radioimmunoassay. The cDNA of Nrg1 is consisted of 2061bp open reading frame encoding 686 amino acids. The deduced amino acid sequence of goose Nrg1 contains one EGF domain from amino acid residues 224 to 265 and shows a closer genetic relationship to the avian species than to other mammal species. The expression level of Nrg1 mRNA increased from the pre-laying period to the peak-laying period, reached its peak in the peak-laying period, and then decreased in the ceased period. The concentrations of FSH and estradiol in blood serum have the similar changing trend. These results might suggest a potential correlation between Nrg1/ErbB signaling network with the reproductive neuroendocrine of Huoyan goose.

Molecular cloning and expression analysis of adiponectin and its receptors (AdipoR1 and AdipoR2) in the hypothalamus of the Huoyan goose during different stages of the egg-laying cycle.

BACKGROUND: Adiponectin and its receptors (AdipoR1 and AdipoR2) are novel endocrine systems that act at various levels to regulate metabolic homeostasis and reproductive processes. We cloned and characterized the cDNA of adiponectin and its receptors from the hypothalamus of the Huoyan goose to reveal the influence of these factors on the process of goose egg-laying. We also determined the mRNA and protein expression profiles during different stages of the egg-laying cycle. METHODS: Hypothalamus tissues were obtained from 36 Huoyan geese in the pre-laying, early-laying, peak-laying, and ceased periods. The cDNA sequences of goose adiponectin and its receptors (AdipoR1 and AdipoR2) were cloned and characterized using the 5'-RACE and 3'-RACE methods. Multiple alignments and phylogenetic analyses of the deduced amino acid sequence were conducted using bioinformatics tools. The expression profiles of mRNA and protein in the hypothalamus during the pre-laying, early-laying, peak-laying and ceased periods were examined using real-time PCR (qRT-PCR) and Western blotting techniques. RESULTS: The cDNA of adiponectin, AdipoR1 and AdipoR2 consisted of 738, 1131 and 1161 bp open reading frame encoding 245, 376 and 386 amino acids, respectively. The deduced amino acid sequence of goose adiponectin, as well as AdipoR1 and AdipoR2 showed a closer genetic relationship to the avian species than to other mammal species. The expression level of adiponectin mRNA and protein increased from the pre-laying period to the peak-laying period, reached its peak in the peak-laying period, and then decreased during the ceased period. Conversely, the expression levels of AdipoR1 and AdipoR2 mRNA and protein decreased in the early-laying period, peak-laying period, and ceased period compared with the pre-laying period. CONCLUSIONS: This study is the first to obtain full-length cDNA sequences of goose adiponectin and the genes of its receptors from the hypothalamus, and demonstrate that the egg-laying cycle affects the expression of the goose adiponectin system. Our results suggest the potential role of adiponectin as a key neuromodulator of reproductive functions.

Transcriptome profiling identifies differentially expressed genes in Huoyan goose ovaries between the laying period and ceased period.

The Huoyan goose is famous for its high egg-laying performance and is listed as a nationally protected domestic animal by the Chinese government. To elucidate the key regulatory genes involved in Huoyan goose egg laying, RNA from ovarian tissue during the ceased and laying periods was sequenced using the Illumina HiSeq 2000 sequencing platform. More than 12 million reads were produced in ceased and laying libraries that included 11,896,423 and 12,534,799 clean reads, respectively. More than 20% of the reads were matched to the reference genome, and 23% of the reads were matched to reference genes. Genes with a false discovery rate (FDR) ≤0.001 and log2ratio ≧1 or ≤-1 were characterized as differentially expressed, and 344 up-regulated and 344 down-regulated genes were classified into functional categories. Twelve genes that are mainly involved in pathways for reproduction regulation, such as steroid hormone biosynthesis, GnRH signaling pathways, oocyte meiosis, progesterone-mediated oocyte maturation, steroid biosynthesis, calcium signaling pathways, and G-protein coupled receptor signaling pathway were selected for validation by a quantitative real-time polymerase chain reaction (qRT-PCR) analysis, the qRT-PCR results are consistent with the general expression patterns of those genes from the Illumina sequencing. These data provide comprehensive gene expression information at the transcriptional level that might increase our understanding of the Huoyan goose's reproductive biology.

Molecular cloning and expression analysis of the synaptotagmin-1 gene in the hypothalamus and pituitary of Huoyan goose during different stages of the egg-laying cycle.

BACKGROUND: Synaptotagmin-1 (Syt1) is an abundant, evolutionarily conserved integral membrane protein that plays essential roles in neurotransmitter release and hormone secretion. Neurotransmitters secreted by hypothalamic neurons can alter GnRH (gonadotropin-releasing hormones) neuronal activity by binding to and activating specific membrane receptors in pituitary cells and, in turn, control the release of gonadotropin hormones from the pituitary gland. To reveal the influence of Syt1 on the process of goose egg-laying, we cloned and characterized the cDNA of goose Syt1 originating from hypothalamus and pituitary tissues of Huoyan goose and investigated the mRNA expression profiles during different stages of the egg-laying cycle. METHODS: Hypothalamus and pituitary tissues were obtained from 36 Huoyan geese in the pre-laying period, early laying period, peak-laying period, and ceased period. The cDNA sequences of goose Syt1 were cloned and characterized from Huoyan goose tissues using 5'-RACE and 3'-RACE methods. Multiple alignments and phylogenetic analyses of the deduced Syt1 amino acid sequence were conducted using bioinformatics tools. The expression profiles of the Syt1 mRNA in the hypothalamus and pituitary during pre-laying, early laying, peak-laying and ceased period were examined using real-time PCR (qRT-PCR). RESULTS: The cDNA of Syt1 consisted of a 274 bp 5' UTR, a 1266 bp open reading frame (ORF) encoding 421 amino acids, and a 519 bp 3' UTR. The deduced amino acid sequence of goose Syt1 is highly conserved with the sequence from other species, especially with birds (more than 98%), and contains two protein kinase C2 conserved regions (C2 domain) from amino acids residue 157 to 259 and 288 to 402. The results of qRT-PCR demonstrated that the expression of Syt1 mRNA increased from the pre-laying period to the peak-laying period, reached its peak in the peak-laying period, and then decreased in the ceased period. CONCLUSIONS: To the best of our knowledge, this study is the first to obtain full-length cDNA sequences of the goose Syt1 gene, and the results of Syt1 mRNA expression profiling in the hypothalamus and pituitary tissues suggested that Syt1 may play an important role in regulating the secretion of hormones relevant to the reproduction and egg-laying of female geese.

Differential expression profiling of hypothalamus genes in laying period and ceased period Huoyan geese.

The hypothalamus plays a central role in controlling poultry reproductive activity. To increase our understanding of genes involved in egg laying of Huoyan geese, gene profiles in the hypothalamus of laying period and ceased period Huoyan geese were investigated using suppression subtractive hybridization (SSH) method. A total of 95 differentially expressed sequence tags (ESTs), including 46 up-regulated and 49 down-regulated sequences showed homology to known genes of the non-redundant NCBI databases. Bioinformatic analysis demonstrated that these genes were mainly involved in anatomical structure development, signal transduction, cellular nitrogen compound metabolic process, biosynthetic process, cellular protein modification process, cell differentiation, transport, cell adhesion, and reproduction. Ten ESTs were selected for further analyses by quantitative real-time RT-PCR (qRT-PCR). Whose most part of results were consistent with the SSH results. Of note, AdipoR2, Nrg1, and NCAM1, which related with secretion of GnRH and other hormones, were identified to be differentially expressed between laying period and ceased period. These findings provided a new source for mining genes related to higher laying performance of Huoyan geese, which facilitate our understanding of the reproductive biology of the goose.

Gene expression profiling in the pituitary gland of laying period and ceased period huoyan geese.

Huoyan goose is a Chinese local breed famous for its higher laying performance, but the problems of variety degeneration have emerged recently, especially a decrease in the number of eggs laid. In order to better understand the molecular mechanism that underlies egg laying in Huoyan geese, gene profiles in the pituitary gland of Huoyan geese taken during the laying period and ceased period were investigated using the suppression subtractive hybridization (SSH) method. Total RNA was extracted from pituitary glands of ceased period and laying period geese. The cDNA in the pituitary glands of ceased geese was subtracted from the cDNA in the pituitary glands of laying geese (forward subtraction); the reverse subtraction was also performed. After sequencing and annotation, a total of 30 and 24 up and down-regulated genes were obtained from the forward and reverse SSH libraries, respectively. These genes mostly related to biosynthetic process, cellular nitrogen compound metabolic process, transport, cell differentiation, cellular protein modification process, signal transduction, small molecule metabolic process. Furthermore, eleven genes were selected for further analyses by quantitative real-time PCR (qRT-PCR). The qRT-PCR results for the most part were consistent with the SSH results. Among these genes, Synaptotagmin-1 (SYT1) and Stathmin-2 (STMN2) were substantially over-expressed in laying period compared to ceased period. These results could serve as an important reference for elucidating the molecular mechanism of higher laying performance in Huoyan geese.

Preventive effect of taurine on experimental type II diabetic nephropathy.

BACKGROUND: It has been verified that taurine has some preventive effects on diabetes and its complications when used alone or together with other drugs, but there are few reports about taurine on the prevention of diabetic nephropathy, the mechanisms of which are still unknown. METHODS: Taurine was administered to type diabetic rats induced by high fat high sugar diet combined with STZ injection. The preventive effect of taurine on diabetic nephropathy was investigated by detecting blood glucose, lipid metabolism, kidney function and glomerular basement membrane metabolism. RESULTS: Taurine could lower blood glucose, TG, TC, BUN, Scr, NAG, U-PRO, the expression of laminin B1(LBN1) mRNA, and increase HDL-C of diabetic rats. CONCLUSIONS: The results indicated that taurine could prevent the occurrence and development of diabetic nephropathy by decreasing blood glucose, improving lipid metabolism, glomerular basement membrane metabolism, and kidney function.

Effect of taurine on alcoholic liver disease in rats.

To investigate the effect of taurine on alcoholic liver disease in rats, male Wistar rats were administered alcohol intragastrically for 3 months. The effect of beta-alanine-mediated taurine depletion and taurine administration on the development of alcoholic liver disease was examined. It was found that taurine administration produced lower levels of aspartate aminotransferase and alkaline aminotransferase than that of the untreated group. In addition, the levels of hepatic total protein, glutathione and superoxide dismutase were higher in the taurine treated groups than in the untreated control or the taurine depleted group, while hepatic malondialdehyde content exhibited the opposite effect. Moreover, the content of hepatic hydroxyproline, serum hyaluronic acid, interleukin-2, interleukin-6, tumor necrosis factor-alpha and laminin were all decreased in the taurine treated group. The pathological changes showed that the percentage of fatty degeneration and inflammation in the taurine group were less than that of the control, taurine depleted and automatic recovery groups. These in-vivo findings demonstrate that hepatic disease caused by chronic alcohol consumption can be prevented and reversed by administration of taurine.

Effect of taurine on alcoholic liver disease in rats.

To investigate the effect of taurine on alcoholic liver disease in rats, male Wistar rats were administered alcohol intragastrically for 3 months. The effect of beta-alanine-mediated taurine depletion and taurine administration on the development of alcoholic liver disease was examined. It was found that taurine administration produced lower levels of aspartate aminotransferase and alkaline aminotransferase than that of the untreated group. In addition, the levels of hepatic total protein, glutathione and superoxide dismutase were higher in the taurine treated groups than those in the untreated control or the taurine depleted groups, while hepatic malondialdehyde content exhibited the negative effect. Moreover, the concentrations of hepatic hydroxyproline, serum hyaluronic acid, interleukin-2, interleukin-6, tumor necrosis factor-alpha and laminin were all decreased in the taurine treated groups. The pathological changes showed that the percentage of fatty degeneration and inflammation in the taurine groups were lower than that of the control, taurine depleted and automatic recovery groups. These in vivo findings demonstrate that hepatic disease caused by chronic alcohol consumption can be prevented and cured by administration of taurine.

[Study on screening differentially expressed genes in mice livers by silver staining DD-PCR].

AIM: To screen swimming-fatigue related genes in mice and lay theoretic basis for researching the molecular mechanism of fatigue. METHODS: 30 male BALB/c mice (20 +/- 2g) were divided into control group, dipping in water group and swimming-fatigue group respectively. After fatigue for swimming in swimming-fatigue group, with control group and dipping in water group, liver tissues in mice were collected. With improved silver staining mRNA differential display method, the differentially expressed genes in mice livers were screened and evaluated by reversed Northern blot. The positive segments were analyzed homology by BLAST. RESULTS: 7 of DD-ESTs were gained. Two of them only expressed in swimming-fatigue group, two down-regulated expressed, and three up-regulated. One of them was a novel gene and was accepted by GenBank, AY615302. CONCLUSION: Seven DD-ESTs in swimming-fatigue mice were gained by silver staining mRNA differential display method.