Strong broodiness is an important reproductive characteristic of Magang geese, manifested by periodic laying-incubation activities during the breeding season. To investigate the changes in ovarian activity, follicular development, and gonadal reproductive regulators during the laying-incubation cycle, this study examined ovarian morphology, follicular development, blood reproductive hormones, and the expressions of reproductive regulators in the gonadal stroma, follicular granulosa, and membranous layer of the follicles during the laying, early broodiness, depth of broodiness, and end of broodiness periods of Magang geese. The results showed that ovarian activity degenerated and atrophied with the onset of brooding: the number of LWFs and SYFs decreased rapidly; LFY disappeared; PRL in the blood increased significantly; FSH, P4, E2, and INH decreased significantly; and the mRNA levels of GnIH and steroidogenic factors were up-regulated in the ovarian stroma. With the termination of brooding, the ovarian activity was gradually restored: the numbers of LWFs and SYFs increased gradually; LYF began to appear; PRL in the blood decreased; FSH and E2 increased; P4 remained low; and expressions of GnIH and steroidogenic factors were down-regulated in the ovarian stroma. During the laying period, with the rapid development of follicles, the expressions of FSHR and GnIH were significantly up-regulated; GnIH expression peaked in the SY granulosa layer, while FSHR expression peaked in the F6 granulosa layer. As LYF developed and ovulation occurred, the expressions of FSHR and GnIH were significantly down-regulated, LHR expression was significantly up-regulated, the expression of GnIHR peaked in the F3 granulosa layer and then declined, PRLR expression was the lowest in the F1 granulosa layer, steroidogenic factor StAR was up-regulated, CYP19A1 was down-regulated, and 3β-HSD peaked in the F3 granulosa layer and then declined. The results indicate that GnIH/GnIHR, FSHR, LHR, and PRLR in the gonad correspond to the upstream reproductive hormones and the jointly regulated steroid hormone production and follicular development, which leads to periodic changes in ovarian activity during the laying-incubation cycle of the breeding season of Magang geese. GnIH/GnIHR might play an important regulatory role for FSHR, LHR, and PRLR in the gonads.

To investigate the regulatory mechanism mediated by hypothalamic OPN5 on seasonal changes in the reproductive activities of domestic geese, 60 Magang ganders in their breeding period were selected for the experiment and evenly divided into an immunization group(OPN5-IM) and a control group. On days 0, 15 and 30, ganders in the immunized group were immunized with OPN5-KLH protein vaccine, and ganders in the control were immunized with the same amount of blank emulsified vaccine. Additionally, 120 female geese were provided to stimulate the reproductive activities of male geese. The results showed that the arrangement of spermatogenic cells was disturbed, the number of sperm decreased, and the testicular weight, seminiferous tubule area, length diameter, spermatogenic epithelium thickness decreased significantly with the natural day length prolonged. Moreover, the concentration of testosterone and LH decreased significantly while PRL increased. The prolonged photoperiod significantly affected the gene expression of GnRH-I, VIP, FSHβ, FSHR, LHβ, PRL, and PRLR in ganders. Specifically, the gene expression of GnRH-I, FSHβ, and LHβ in the hypothalamus and pituitary decreased, while the gene expression of VIP, PRL, and PRLR increased. Following OPN5 immunization, the anti-OPN5 antibody titer of ganders in the OPN5-IM group was notably higher than in the control group. The testicular degeneration was severe in OPN5-IM group compared with the control, as evidenced by a significant reduction in seminiferous tubule area, length diameter, and thickness of spermatogenic epithelium in the immunized group on day 60. Additionally, the concentrations of testosterone and LH were lower in the OPN5-IM group than in the control group, whereas PRL was higher. Moreover, OPN5 immunization significantly affected the expression of GnRH-I, PRL, and PRLR. OPN5 mRNA and protein expression were higher in the immunized group, whereas TRH, DIO2, and TSHR mRNA expressions were lower. However, DIO3 mRNA and protein were up-regulated in the immunized group. In conclusion, our results indicated that the reproductive performance of Magang geese degraded from the breeding to the non-breeding period as daylight was extended. Immunization against OPN5 increased OPN5 expression and down-regulated the TSH-DIO2/DIO3 pathway, further to affect the HPG axis and accelerate the degradation of reproductive activity. Therefore, OPN5 may play an important mediating role in light-regulating seasonal reproductive degradation in Magang geese.

Photoperiod is an important environmental factor that influences seasonal reproduction behavior in birds. Birds translate photoperiodic information into neuroendocrine signals through deep brain photoreceptors (DBPs). OPN5 has been considered candidate DBPs involved in regulating seasonal reproduction in birds. We found that OPN5 could mediate light to regulate the follicle development in ducks. In this study, we further verified the effect of OPN5 on follicular development in Shan Partridge ducks by immunizing against the extracellular domain (ECD) of OPN5. We investigated the specific regulatory mechanism of photoperiod mediated by OPN5 on the reproductive activity of ducks. The trial randomly divided 120 Shan Partridge ducks into 3 groups with different treatments: the immunization of OPN5 group was done at d0, d15, d30, and d40 with 1 mL of vaccine containing OPN5 protein (thus containing 1, 1, 0.5, and 0.5 mg of OPN5-KLH protein), and the control group (CS and CL groups) was injected at the same time with the same dose of OPN5-uncontained blank vaccine. The group of CS (900 lux), OPN5 (600 lux), and CL (600 lux) lasted for 40 d in 12 L:12 D photoperiods, respectively. Then, the groups of CS, OPN5, and CL subsequently received 12 L:12 D, 12 L:12 D, and 17 L:7 D light treatments for 33 d, respectively. The ducks were caged in 3 constant rooms with the same feeding conditions for each group, free water, and limited feeding (150 g per duck each day). Duck serum and tissue samples were collected at d 40, d 62, and d 73 (n = 12). It was found that before prolonged light, the group of immunization (group OPN5) and the group of strong light intensity (group CS) were higher than the group of CL in egg production. Subsequent to prolonged light, the group CL in egg production rose about the same as the group immunization, while the strong light group (group CS) was lower. Group OPN5 increased the ovarian index of ducks, and both the immunization of group OPN5 and group CL (extended light) increased the thickness of the granular layer and promoted the secretion of E2, P4, LH, and PRL hormones. Compared with group CS, group CL and OPN5 increased the mRNA level and protein expression of OPN5 in the hypothalamus on d 62 and d 73 (P < 0.05). The gene or protein expression patterns of GnRH, TRH, TSHβ, DIO2, THRβ, VIP, and PRL were positively correlated with OPN5, whereas the gene expression patterns of GnIH and DIO3 were negatively correlated with OPN5. The results showed that immunization against OPN5 could activate the corresponding transmembrane receptors to promote the expression of OPN5, up-regulate the expression of TSHβ and DIO2, and then regulate the HPG axis-related genes to facilitate the follicular development of Shan Partridge ducks. In addition, in this experiment, prolonging the photoperiod or enhancing the light intensity could also enhance follicle development, but the effect was not as significant as immunizing against OPN5. Our results will offer beneficial data and more supportive shreds of evidence in favor of elucidating the role of OPN5 in relation to photoperiods and reproduction.

OPN5 is one of the main deep brain photoreceptors (DBPs), converting photoperiodic information into neuroendocrine signals to regulate reproduction in birds. This study investigated the mechanism of OPN5-mediated photoperiodic regulation of reproduction by active immunization against OPN5. 96 female quail were divided into OPN5-immunized and control group under the same photoperiod: 16 L:8 D (d 1 to d 35), 8 L:16 D (d 36 to d 70) and 12 L:12 D (d 71 to d 126). OPN5-immunized group was conducted with OPN5 protein vaccination and control group was given a blank vaccine. Samples were collected on d 1, d 30, d 60, and d 126. Results showed switching photoperiod to 8 L:16 D decreased the laying rate, GSI%, numbers of YFs and WFs, serum levels of PRL, P4 and E2, and pituitary PRL and TSHβ protein expressions in both groups (P < 0.05). Whereas the OPN5-immunized group exhibited higher laying rates than the control group (P < 0.05). The control group showed reduced GnRHR and TSHβ gene expressions in the pituitary and increased GnIH and DIO3 transcript and/or protein abundance in the hypothalamus. (P < 0.05). The OPN5-immunized group had lower DIO3 expression at both mRNA and protein levels. (P < 0.05). Switching photoperiod from 8 L:16 D to 12 L:12 D increased the laying rates, GSI%, numbers of YFs and WFs, serum levels of PRL, and PRL protein expression in both groups (P < 0.05), and the responses were more pronounced in OPN5-immunized group (P < 0.05). In contrast to the control group, quail with OPN5-immunization had higher OPN5 and DIO2 transcript and/or protein levels but lower DIO3 expressions in the hypothalamus along the transition photoperiods (P < 0.05). The results revealed that OPN5 responds to photoperiod transition, and its activation mediates related signaling to up-regulate TSH-DIO2/DIO3 pathway and VIP-PRL secretion to prime quail reproductive functions.

Background In cold and temperate zones, seasonal reproduction plays a crucial role in the survival and reproductive success of species. The photoperiod influences reproductive processes in seasonal breeders through the hypothalamic-pituitary-gonadal (HPG) axis, in which the mediobasal hypothalamus (MBH) serves as the central region responsible for transmitting light information to the endocrine system. However, the cis-regulatory elements and the transcriptional activation mechanisms related to seasonal activation of the reproductive axis in MBH remain largely unclear. In this study, an artificial photoperiod program was used to induce the HPG axis activation in male quails, and we compared changes in chromatin accessibility changes during the seasonal activation of the HPG axis. Results Alterations in chromatin accessibility occurred in the mediobasal hypothalamus (MBH) and stabilized at LD7 during the activation of the HPG axis. Most open chromatin regions (OCRs) are enriched mainly in introns and distal intergenic regions. The differentially accessible regions (DARs) showed enrichment of binding motifs of the RFX, NKX, and MEF family of transcription factors that gained-loss accessibility under long-day conditions, while the binding motifs of the nuclear receptor (NR) superfamily and BZIP family gained-open accessibility. Retinoic acid signaling and GTPase-mediated signal transduction are involved in adaptation to long days and maintenance of the HPG axis activation. According to our footprint analysis, three clock-output genes (TEF, DBP, and HLF) and the THRA were the first responders to long days in LD3. THRB, NR3C2, AR, and NR3C1 are the key players associated with the initiation and maintenance of the activation of the HPG axis, which appeared at LD7 and tended to be stable under long-day conditions. By integrating chromatin and the transcriptome, three genes (DIO2, SLC16A2, and PDE6H) involved in thyroid hormone signaling showed differential chromatin accessibility and expression levels during the seasonal activation of the HPG axis. TRPA1, a target of THRB identified by DAP-seq, was sensitive to photoactivation and exhibited differential expression levels between short- and long-day conditions. Conclusion Our data suggest that trans effects were the main factors affecting gene expression during the seasonal activation of the HPG axis. This study could lead to further research on the seasonal reproductive behavior of birds, particularly the role of MBH in controlling seasonal reproductive behavior.

Magang geese are typical short-day breeders whose reproductive behaviors are significantly influenced by photoperiod. Exposure to a long-day photoperiod results in testicular regression and spermatogenesis arrest in Magang geese. To investigate the epigenetic influence of DNA methylation on the seasonal testicular regression in Magang geese, we conducted whole-genome bisulfite sequencing and transcriptome sequencing of testes across 3 reproductive phases during a long-day photoperiod. A total of 250,326 differentially methylated regions (DMR) were identified among the 3 comparison groups, with a significant number showing hypermethylation, especially in intronic regions of the genome. Integrating bisulfite sequencing with transcriptome sequencing data revealed that DMR-associated genes tend to be differentially expressed in the testes, highlighting a potential regulatory role for DNA methylation in gene expression. Furthermore, there was a significant negative correlation between changes in the methylation of CG DMRs and changes in the expression of their associated genes in the testes. A total of 3,359 DMR-associated differentially expressed genes (DEG) were identified; functional enrichment analyses revealed that motor proteins, MAPK signaling pathway, ECM-receptor interaction, phagosome, TGF-beta signaling pathway, and calcium signaling might contribute to the testicular regression process. GSEA revealed that the significantly enriched activated hallmark gene set was associated with apoptosis and estrogen response during testicular regression, while the repressed hallmark gene set was involved in spermatogenesis. Our study also revealed that methylation changes significantly impacted the expression level of vitamin A metabolism-related genes during testicular degeneration, with hypermethylation of STRA6 and increased calmodulin levels indicating vitamin A efflux during the testicular regression. These findings were corroborated by pyrosequencing and real-time qPCR, which revealed that the vitamin A metabolic pathway plays a pivotal role in testicular degeneration under long-day conditions. Additionally, metabolomics analysis revealed an insufficiency of vitamin A and an abnormally high level of oxysterols accumulated in the testes during testicular regression. In conclusion, our study demonstrated that testicular degeneration in Magang geese induced by a long-day photoperiod is linked to vitamin A homeostasis disruption, which manifests as the hypermethylation status of STRA6, vitamin A efflux, and a high level of oxysterol accumulation. These findings offer new insights into the effects of DNA methylation on the seasonal testicular regression that occurs during long-day photoperiods in Magang geese.

在半旱养模式中,洗浴池水体在鹅养殖中起到关键作用,洗浴池水体污染会造成细菌滋生,传播疾病,影响鹅的生长与繁殖性能.该试验旨在研究净水剂(聚合硫酸铝)对鹅粪污水的净化效果.该试验在 100mL鹅粪稀释液(模拟养殖污水)中通过添加不同浓度的PAS(1×10-3、1×10-4、1×10-5g/mL)对1%、2.5%、5%的污水稀释液进行处理.结果表明,在 1%、2.5%、5%的鹅养殖污水中,添加浓度为 1×10-4g/mL、1×10-5g/mL的PAS,对大肠杆菌与总菌落无显著影响(P＞0.05);浓度为 1×10-3g/mL的PAS能够显著降低大肠杆菌与总菌落的数量,并在浓度为5%的养殖污水中显著降低污水中的悬浮物、化学需氧量、磷酸盐含量(P＜0.05).可见,浓度为 1×10-3g/mL的PAS能够显著减少总菌落与大肠杆菌数量,在5%浓度的鹅养殖污水中,聚合硫酸铝能够显著改善水质.

Goose is an important poultry commonly raised for meat. The early growth performance of geese significantly influences their market weight and slaughter weight, affecting the poultry industry’s economic benefits. To identify the growth surge between the Shitou goose and the Wuzong goose, we collected the early growth body traits from 0 to 12 weeks. In addition, we investigated the transcriptomic changes in leg muscles at the high growth speed period to reveal the difference between the two geese breeds. We also estimated the growth curve parameters under three models, including the logistic, von Bertalanffy, and Gompertz models. The results showed that except for body length and keel length, the best-fitting model between the body weight and body size of the Shitou and Wuzong was the logistic model. The growth turning points of Shitou and Wuzong were 5.954 and 4.944 weeks, respectively, and the turning point of their body weight was 1459.01 g and 478.54 g, respectively. Growth surge occurred at 2–9 weeks in Shitou goose and at 1–7 weeks in Wuzong goose. The body size traits of the Shitou goose and Wuzong goose showed a trend of rapid growth in the early stage and slow growth in the later stage, and the Shitou goose growth was higher than the Wuzong goose. For transcriptome sequencing, a total of 87 differentially expressed genes (DEGs) were identified with a fold change ≥ 2 and a false discovery rate < 0.05. Many DEGs have a potential function for growth, such as CXCL12, SSTR4, FABP5, SLC2A1, MYLK4, and EIF4E3. KEGG pathway analysis identified that some DEGs were significantly enriched in the calcium signaling pathway, which may promote muscle growth. The gene–gene interaction network of DEGs was mainly related to the transmission of cell signals and substances, hematological system development, and functions. This study can provide theoretical guidance for the production and breeding management of the Shitou goose and Wuzong goose and help reveal the genetic mechanisms underlying diverse body sizes between two goose breeds.

BACKGROUND:Domestic geese are seasonal breeders and have the lowest reproductive capacity among all poultry species. Magang geese is a topical short-day breeder, short photoperiod exposure stimulates its reproductive activity while long photoperiod inhibits. To explore epigenetic change that could influence reproductive activity, we performed whole genome bisulfite sequencing and transcriptome sequencing in the hypothalamus at three reproductive stages during long-light exposure in male Magang geese.RESULTS:A total number of 10,602 differentially methylated regions (DMRs) were identified among three comparison groups. We observed that the vast majority of DMRs were enriched in intron regions. By integrating the BS-sequencing and RNA-seq data, the correlation between methylation changes of CG DMRs and expression changes of their associated genes was significant only for genes containing CG DMRs in their intron. A total of 278 DMR-associated DEGs were obtained among the three stages. KEGG analysis revealed that the DMR-associated DEGs were mainly involved in 11 pathways. Among them, the neuroactive ligand-receptor interaction pathway was significantly enriched in both two comparisons (RA vs.RD and RD vs.RI); the Wnt signaling pathway, apelin signaling pathway, melanogenesis, calcium signaling pathway, focal adhesion, and adherens junction were significantly enriched in the RA vs. RI comparison. In addition, the expression level of two serotonin-metabolic genes was significantly altered during reproductive axis inactivation by the methylation status of their promoter region (TPH2) and intron region (SLC18A2), respectively. These results were confirmed by Bisulfite sequencing PCR (BSP), pyrosequencing, and real-time qPCR, indicating that serotonin metabolic signaling may play a key role in decreasing the reproductive activity of Magang geese induced by long-light exposure. Furthermore, we performed a metabolomics approach to investigate the concentration of neurotransmitters among the three stages, and found that 5-HIAA, the last product of the serotonin metabolic pathway, was significantly decreased in the hypothalamus during RI.CONCLUSIONS:Our study reveals that the methylation status of the serotonin metabolic pathway in the hypothalamus is associated with reproductive inactivation, and provided new insight into the effect of DNA methylation on the reproductive regulation of the hypothalamus in Magang geese.

The hypothalamic-pituitary-gonad (HPG) axis is vital for reproductive activities in vertebrates. The large-scale comparative analyses of gene expression in the HPG axis across vertebrates have not been carried out yet. Here we collected 175 high-quality RNA-seq samples of hypothalamus, pituitary, ovary and testis from eight species (four mammals and four poultry) to compare transcriptome in the HPG axis, and to detect key pathways and related genes associated with reproduction. We demonstrated the distinguished difference in gene expression of the HPG axis between mammalian and avian species by a series of bioinformatics analysis, including gene differential expression, the phylogeny analysis of gene expression, and their functional annotations. We revealed two pathways, i.e., neuroactive ligand-receptor interaction and calcium signaling pathway, which play important roles in animal reproduction. In these two pathways, we detected 17 differentially expressed genes shared in 4 tissues, while 13, 27, and 27 were specifically differentially expressed genes in hypothalamus, pituitary and ovary, respectively. Our study on the comparative transcriptomics in the HPG axis across species will provide novel knowledge for exploring the molecular mechanism underlying reproductive traits in animals.

Abstract: Photoperiod is an important environmental factor that influence seasonal reproduction behavior in bird. Birds translates photoperiodic information into neuroendocrine signals through deep brain photoreceptors (DBPs). OPN5 has been considered as candidate DBPs involving in regulation of seasonal reproduction in birds. However, little is known about the effect of OPN5 in non-seasonal breeding birds. Thus, we pondered on whether OPN5 regulating follicular development through TSH-DIO2/DIO3 system responds to different photoperiods in non-seasonal laying ducks. As an ideal non-seasonal breeding bird, a total of 120 mountain ducks were randomly divided into three groups and treated respectively to a different photoperiod: group S (8 L:16D), group C (17 L:7D), and group L (24 L:0D). The ducks were caged in a fully enclosed shelter with the same feeding conditions for each group, free water and limited feeding (150 g per duck each day). Samples were collected from each group at d 0, d 5, d 8, d 20, and d 35 (n = 8). The ducks in 24 h photoperiod had the highest laying rate and the lowest feed-to-egg ratio, while the ducks in 8 h photoperiod had the lowest laying rate and the highest feed-to-egg ratio. Long-day photoperiod for 24 h significantly increased the ovarian index and GnRH, LH, E2, and P4 levels in serum; short-day photoperiod for 8 h increased testosterone levels in serum. Compared with 8 h photoperiod, long-day photoperiod significantly or highly significantly increased the mRNA level and protein expression of OPN5 in the hypothalamus of long-day photoperiod on d 35 (p < 0.05). The gene or protein expression patterns of GnRH, TRH, TSHβ, DIO2, THRβ, VIP, and PRL were positively correlated with OPN5, whereas the gene expression patterns of GnIH and DI O 3 were negatively correlated with OPN5. The results revealed that OPN5 mediated the effect of light on follicular development through the TSH-DIO2/DIO3 pathway, the expression of OPN5 increased with light duration and improved the efficiency of the HPG axis to promote follicular development in mountain ducks.

[目的]探究外源性RF-酰胺相关肽3(RF-amide related peptide 3,RFRP-3)和褪黑素(melatonin,MLT)对雄性昆明小鼠初情期生长、繁殖性能的影响及两者之间的关系.[方法]以初情期雄性昆明小鼠为研究对象,单独给予雄鼠生理盐水、外源性RFRP-3或MLT以及混合给予RFRP-3、MLT,检测其对雄鼠平均增重、平均采食量、料重比、睾丸发育情况,血清生长激素(growth hormone,GH)、黄体生成素(luteinizing hormone,LH)水平,以及生长、生殖相关基因表达的影响.[结果]外源性RFRP-3能抑制雄鼠GH基因表达,并抑制体重增长,提高料重比;而外源性MLT促进雄鼠GH基因表达,使体重增长较快,料重比降低;RFRP-3和MLT共同处理下,GH基因表达增加,体重增长速度与单独给予MLT组接近.RFRP-3可抑制褪黑素受体1A(melatonin receptor 1A,Mtnr1A)、LH基因表达及睾酮分泌,小鼠睾丸各级生精细胞和间质细胞数量减少;MLT可促进Mtnr1A、LH基因表达及睾酮分泌,睾丸间质细胞密度极显著增加(P＜0.01);MLT和RFRP-3共同处理下,小鼠睾丸各级生精细胞和间质细胞数量减少,睾酮分泌显著减少(P＜0.05).[结论]外源性RFRP-3能一定程度抑制雄性小鼠初情期的生长及繁殖性能,外源性MLT可促进初情期雄性小鼠的生长及繁殖性能.

This study sought to understand the regulation mechanism of OPN5 through the TSH-DIO2/DIO3 pathway mediated photoperiod on the breeding activity of short-day breeding birds. In this study, the reproductive activity of Magang goose was regulated by artificial light, and the reproductive activity of the ganders were determined according to the daily laying rate of female geese. The testicular development and the serum reproductive hormone concentrations of ganders were measured during the reproductive period (d 0), the reproductive degeneration period (d 13 and 27) and the resting period (d 45). The mRNA and protein expression patterns of OPN5, the HPG axis reproductive genes, and TSH-DIO2/DIO3 pathway related genes were examined. Results showed that the laying rate of geese and the gonadal indices (GSI) decreased gradually after the photoperiod increased. Histological observation found that the spermatogenic function of the testis was normal on d 0 and 13, while degeneration occurred by d 27 and 45. Serum testosterone, FSH, and LH concentration showed a slight increase on d 13, followed by a sharp decrease on d 27 and 45 (P < 0.01), while PRL concentrations were low on d 0 and 13, and increased rapidly on d 27 and 45 (P < 0.01).The expression pattern of GnRH, FSH, LH, and THRβ mRNA were similar, with high levels on d 0 and 13 and a decreasing trend on d 27 and 45 (P < 0.05 or P < 0.01); and GnRHR mRNA levels were higher on d 13 (P < 0.05), but then had decreased by d 27 and 45 (P < 0.01). The expression pattern of GnIH and GnIHR was similar, which was opposite to that of GnRHR. VIP, PRL, and PRLR increased gradually and peaked on d 45 (P < 0.01). The expression trend of TRH, TSHβ, and DIO2 was similar to that of GnRHR, and the expression abundance increased on d 13, and then decreased on d 27 and 45. GnRH protein expression was significantly higher than during the other 3 periods (P < 0.01) while the GnIH protein levels were extremely low on d 0, had gradually increased by d 13, and significantly increased by d 27 and 45 (P < 0.01). The protein expression trends of THR and DIO2 were similar to that of GNIH. DIO3 protein expression was low on d 0 and 13, and increased by d 27 and 45. These results suggest that when the photoperiod increased, the hypothalamus OPN5 gene and protein were upregulated and the pituitary TSHβ, TSHR, and hypothalamus THRβ, TRH, and DIO2 were downregulated, and thus the reproductive activity of geese was inhibited.

Photoperiod is an important environmental factor affecting animal physiological function. Melatonin is an endogenous hormone that plays an important role in circadian and seasonal (or cyclical) rhythms and seasonal reproduction in mammals. To investigate the effects of melatonin on the reproductive performance of adult male mice under different photoperiods, sixty mice were randomly allotted to six groups: control (Light Dark, 12 L:12 D), control plus melatonin (MLD, 12 L:12 D), 24-hour continuous light (LL, 24 L:0 D), 24-hour continuous light plus melatonin (MLL 24 L:0 D), constant darkness (DD, 0 L:24 D), and constant darkness plus melatonin (MDD, 0 L:24 D). Normal saline (100 μL) was injected into the LD, LL, and DD groups at noon each day; the MLD, MLL, and MDD groups were injected with melatonin (1 mg/mL; 2 mg/kg·body weigh). After 24 hours of prolonged light exposure, testis morphology decreased, convoluted seminiferous tubules became sparse, the diameter of convoluted seminiferous tubules decreased, and the level of sex hormones decreased. After the administration of exogenous melatonin, testicular morphology and sex hormone levels decreased in the MLD group under normal light conditions. In the MLL group, the testicular tissue morphology returned to normal, the diameter of convoluted tubules increased, the hormone levels of LH (Luteinizing hormone) and MTL (melatonin) significantly increased (P<0.05), and th0e gene expressions of LHβ and Mtnr1A (Melatonin receptors 1A) increased. There was almost no difference in the MDD group under continuous darkness. In conclusion, melatonin can damage the reproductive performance of male mice under normal light conditions, while exogenous melatonin can alleviate and protect the testicular injury of male mice under continuous light conditions.

Both hypothalamic neurotransmitters and serum steroid hormones are impacted by photoperiod and have effects on physiology and seasonal reproductive. However, the relationship between circulating gonadal steroids and hypothalamic neurotransmitters underlying different photoperiod is still unclear. To further understand the crosstalk of neurotransmitters and steroids in seasonal reproduction, metabolic changes of 27 neurotransmitters concentrated in hypothalamus tissues and 42 steroids hormones in serum were assessed during two artificial photoperiodic programs. The results showed that photoperiod induce testicular atrophy and recrudescence. In L-to-S groups, significantly decreased levels of testosterone concentration were found in serum (P< 0.001) and increased 11-Dehydrocorticosterone (P< 0.05); Testosterone were almost undetectable at SD_14d. In addition, the hypothalamus exhibited significantly increased arginine and 4-aminobutyric acid (GABA) concentration and decreased serotonin and epinephrine content (P< 0.01 orP< 0.05). Accordingly, serum testosterone and androstenedione became detectable at LD_3d in the S-to-L group and were markedly increase at LD_7d. Furthermore, Serum androstenedione showed a significant increase with long light expose (P< 0.01). Additionally, the hypothalamus exhibited both significantly increased L.Tryptophan and phenylalanine concentration, as well as decreased L-glutamine and L-glutamine.acid content (P< 0.01 orP< 0.05). Serotonin metabolism showed significant differences between L-to-S group and S-to-L group. Furthermore, in the correlation analysis, serum testosterone had a positive correlation with 5-Hydroxyindole-3-acetic acid (5-HIAA), while Androstenedione was significantly negative with L.Tryptophan in L-to-S (P< 0.05). However, in S-to-L group, serum testosterone showed strong negative correlation with both serotonin and 5-HIAA (P< 0.05), but positive correlation with L.Tryptophan (P< 0.01), while Androstenedione was significantly negative correlation with both serotonin (P< 0.05) and L-Glutamine (P< 0.01). Photoperiod also had significant effects on the mRNA expression. We found significant differences in gene expression patterns of both serotonin signaling and steroid biosynthesis, whileMAOB,NR5A1, and3β-HSDshowed an opposite tendency between two groups. Taken together, our results revealed that circulating gonadal steroids and hypothalamic neurotransmitters were significantly impact quail’s seasonal reproduction. Circulating gonadal steroids have different effects on neurotransmitter at different photoperiodism, which may coordinately influence the seasonal reproduction of quails.

为了研究不同浓度GnIH对鸭颗粒细胞周期、增殖及相关基因表达的影响.本研究分别用不同浓度GnIH(0、0.1、1、10和100 ng ? mL-1)处理体外培养的鸭颗粒细胞24 h(n=3),观察细胞的生长状态,通过流式细胞术和EdU方法检测细胞周期和细胞增殖,并用qRT-PCR方法检测增殖相关基因CDK6、CyclinD1、IGF-2、IGFBP-2、p27kip1的表达.结果显示,各浓度GnIH处理组的细胞生长状态良好,形态正常,细胞轮廓清晰,组间死亡细胞数差异不显著(P＞0.05);在0.1和1 ng ? mL-1 GnIH处理组,细胞周期阻滞在G2期的比例显著上升(P＜0.05);随着GnIH处理浓度的增加,EdU阳性细胞数所占的百分比降低;在0.1和1 ng ? mL-1 GnIH处理组,颗粒细胞中CDK6、CyclinD1、IGF-2、IGFBP-2、p27kip1基因的相对表达量均下降,在10和100ng? mL-1 GnIH处理组中这些基因的相对表达量则有所上升.研究表明,在体外培养的鸭颗粒细胞中,GnIH能使细胞周期阻滞在G2期,并降低EdU阳性细胞所占百分比和下调增殖相关基因的表达水平,从而抑制颗粒细胞增殖来影响动物繁殖性能.

为揭示马岗鹅的生长发育规律,挖掘马岗鹅的生长潜力,本研究通过测定马岗鹅0～12周龄的体重和体尺性状,并用Logistics、Von Bertalanffy和Gompertz 3种模型进行生长曲线拟合.结果表明:马岗鹅体重生长曲线最佳模型为Gompertz模型(R2=0.999),拐点周龄是4.31周龄,拐点体重是1459.01 g,2～8周龄的周增重都在320 g以上,相对生长率都在16％ 以上,8周龄前为马岗鹅体重迅速增长时期.胸深、龙骨长、颈长的最佳拟合模型为Gompertz,拐点周龄分别为0.65、3.71、2.28周龄;体斜长、半潜水长的最佳拟合模型为Von Bertalanffy,拐点周龄分别为0.53、0.47周龄;胸宽、骨盆宽、胫长、胫围的最佳拟合模型为Logistic,拐点周龄分别为3.81、1.39、0.91、0.51周龄;7周龄前为马岗鹅体尺性状迅速增长时期.本研究结果可为马岗鹅的生产和饲养管理提供理论指导.

为探讨催乳素(PRL)在垂体层面对禽类生殖的调控机制,以原代培养的鸡胚垂体细胞为材料,研究不同PRL处理浓度和不同处理时间下鸡胚垂体细胞促性腺激素分泌和生殖相关基因表达的变化.结果显示,用5 ng/mL和50ng/mL的PRL处理鸡胚垂体细胞24h,对PRLR表达有先抑制后促进作用,对LHβ表达则呈现明显促进作用,对GnRHR和FSHβ表达无显著影响;而对培养液中LH和FSH浓度均无显著影响.当处理时间为12 h时,与对照组相比,50 ng/mL PRL组显著抑制鸡胚垂体细胞分泌LH和FSH;并且在处理12 h后,PRL能抑制LHβ、FSHβ、GnRHR和TGFBR3的表达,而对PRLR和GnIHR的表达水平均无显著影响.研究结果表明,PRL在垂体层面对促性腺激素的分泌和促生殖相关基因表达具有抑制作用.

In quantitative PCR research, appropriate reference genes are key to determining accurate mRNA expression levels. In order to screen the reference genes suitable for detecting gene expression in tissues of the reproductive axis, a total of 420 (males and females = 1:5) 3-year-old Magang geese were selected and subjected to light treatment. The hypothalamus, pituitary and testicular tissues were subsequently collected at different stages. Ten genes including HPRT1, GAPDH, ACTB, LDHA, SDHA, B2M, TUBB4, TFRC, RPS2 and RPL4 were selected as candidate reference genes. The expression of these genes in goose reproductive axis tissues was detected by real-time fluorescent quantitative PCR. The ΔCT, geNorm, NormFinder and BestKeeper algorithms were applied to sort gene expression according to stability. The results showed that ACTB and TUBB4 were the most suitable reference genes for the hypothalamic tissue of Magang goose in the three breeding stages; HPRT1 and RPL4 for pituitary tissue; and HPRT1 and LDHA for testicular tissue. For all three reproductive axis tissues, ACTB was the most suitable reference gene, whereas the least stable reference gene was GAPDH. Altogether, these results can provide references for tissue expression studies in geese under light treatment.

Insulin-like growth factor 1 (IGF1) is one of the endocrine hormones that plays an important role in regulating growth and development of animals. In this study, polymorphism in the 5′UTR and 3′UTR coding region and of the IGF1 gene was detected by DNA sequencing technology, and the abundance of IGF1 mRNA in various tissues at three growth stages of the Shitou goose was determined by quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, the differential expression of IGF1 in various tissues between the Shitou goose and Wuzong goose was revealed. Two single nucleotide polymorphisms (SNPs) were found in the exon3 region of IGF1 in the Shitou goose. IGF1 mRNA was extensively expressed in various tissues of Shitou geese with high abundant expression in the liver, breast muscle and leg muscle at three growth stages. IGF1 mRNA expression showed a trend of first increase and then decrease in the pituitary, liver, subcutaneous fat and abdominal fat tissues, but it decreased in the breast muscle and leg muscle of a Shitou goose with growing age. Expression of IGF1 in the liver, leg muscle and pituitary tissues of the Shitou goose was significantly higher than that of the Wuzong goose. This provides a foundation for further study of regulatory mechanisms of IGF1 in the growth and development of geese.