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Sperm storage tubules (SST) in broiler breeders and turkeys. A) In this squash preparation of a broiler’s proximal region of the uterovaginal junction (UVJ) folds, the SST were conspicuously short, some no more than 40 μm in length. Bar = 500 μm. B and C) In these squash preparations, SST in the middle regions of the broiler’s UVJ folds varied in length, with some reaching 700 μm in length (arrow in panel B), and exhibited a straight or curved morphology. Microfurrows (highlighted within box in panel B and at increased magnification in panel E) are also observed leading to the SST orifices. Bar = 500 μm. D) Broiler hen SST in the distal region of the UVJ folds in this squash preparation possessed characteristics of the middle region SST but were less densely distributed. Bar = 500 μm. E) Higher magnification of the box in panel B, which clearly shows a microfurrow leading to the SST orifices (short arrows). An oval, puckered, slit-like opening is the common orifice for 2 SST (long arrow). Bar = 300 μm. F) The extension of turkey’s SST epithelium into the UVJ lumen and the abrupt transition to the ciliated epithelium of the UVJ lumen (arrow) is readily apparent in this histological preparation. Sperm are observed within the SST. Bar = 50 μm.
Source publication
The biological basis of sustained fertility in broiler and turkey hens is their capacity to store sperm in the oviductal sperm storage tubules (SST) located in the uterovaginal junction. The objectives of this study were to determine if the numbers of SST varied between 4 strains of broiler breeders and determine the number of SST in the turkey bef...
Contexts in source publication
Context 1
... SST in the proximal region of the UVJ folds in broiler hens were conspicuously short, some no more than 40 μm in length ( Figure 1A). Short SST in the turkey UVJ were similar to those of the broiler as well as to the short SST reported previously ( Bakst and Vinyard, 2002). ...
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... the middle region of the broiler's UVJ folds ( Figures 1B and C), the SST were up to 700 μm long and straight to curvy. In contrast, the turkey SST in the middle region were up to 900 μm in length and were characterized by their pleomorphic morphology consist- ing of straight, convoluted, or coiled SST (Bakst, 1987;Bakst and Vinyard, 2002). ...
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... contrast, the turkey SST in the middle region were up to 900 μm in length and were characterized by their pleomorphic morphology consist- ing of straight, convoluted, or coiled SST (Bakst, 1987;Bakst and Vinyard, 2002). The SST in the distal re- gion of the UVJ folds possessed characteristics of the middle region SST but were less densely distributed, with their presence gradually dissipating in the vagina ( Figure 1D). ...
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... a few squash preparations revealed mi- crofolds on the surface mucosa leading to the orifice of the SST in both broilers and turkeys. The microfolds were narrow furrows up to 800 μm long consisting of tightly apposed ciliated epithelial cells ( Figure 1E). The SST orifice was bounded by ciliated cells that had a puckered appearance when viewed under the stereomi- croscope. ...
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... turkeys, the SST orifice was also fully sur- rounded by ciliated cells. However, histological sections revealed that the border of ciliated cells lining the SST orifice was occasionally interrupted by an exteriorized extension of the SST epithelium that merged abruptly with the UVJ surface epithelium in the lumen of the UVJ ( Figure 1F). In histological sections, microfolds were observed primarily on the lateral surfaces of the primary and secondary mucosal UVJ folds. ...
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Citations
... Wang et al. 2023). Moreover, TGF-beta signalling pathway (PPP2CA and CUL1) is responsible for immunosuppression and regulation of epithelial cell function (Bakst et al. 2010;Das et al. 2006) and adherens junction (CSNK2A1 and ACTN) is responsible for cell adhesion, barrier function and signal transport (Brady et al. 2023;Brady et al. 2022;Das et al. 2008) which is crucial for maintaining the long DF in chicken. The KRAS protein mainly regulates cellular processes, and GTP binding activates KRAS for continuous lactic acid production, which has been discussed before (Ducummon and Berger 2006;L. ...
1. This study determined the effective indicators and proteins involved in long-duration fertility (DF)
in chickens.
2. Three lines of Chinese Xinhua chickens (900) were compared using seven phenotypic trait indicators, and the best was determined based on repeatability value. Subsequently, differential
expression analysis, functional annotation and protein-protein interaction (PPI) network analyses were performed to investigate the pathways and hub proteins. Finally, qPCR analysis was conducted to validate the expression of identified hub proteins, and functional annotation with previously published genes was performed to explain how hub proteins work to maintain the trait.
3. The study found that the number of fertilised eggs (FN) and maximum fertilised eggs (MCF) were
the most repeatable among the seven indicators. It identified 231 differentially expressed proteins, with 144 being down-regulated and 87 being up-regulated. The differentially expressed proteins exhibited high clustering within various cellular compartments, including the cytosol and cytoplasm and GTP binding. Multiple pathways were identified, including tight and adherens junctions, TGF-
beta signalling, autophagy-animal, regulation of actin cytoskeleton and the ribosome that may regulate the trait. Three hub proteins, KRAS, RPL5 (p < 0.001), and HSPA4 (p < 0.01), were significantly differentially expressed between high and low DF groups.
4. This study identified FN and MCF as effective indicators for addressing DF. As it is a quantitative trait, KRAS, HSPA4, and RPL5 are potential hub proteins that work with other genes to maintain the trait.
... over one month. Therefore, artificial insemination only needs to be carried out once a month in the production process of fertile turkey eggs 22,25 . In some commercial lines, including chickens (White leghorn and Jinghong hens) and ducks (Anas platyrhyncha domestica), their DF characteristics are generally less than two weeks 5,12 . ...
The duration-of-fertility (DF), which was defined as the number of days when breeding hens lay fertile eggs following copulation or artificial insemination (AI), is an important economic trait in chick production when it has strong effects on fertile egg output and production costs. Little is known about the underlying genes and molecular markers related to DF trait to date. Here, we measured the DF of 701 Chinese Jinghong hens and 408 Jingfen hens. The DF showed high individual variability and potential for genetic improvement. Then, 192 Jinghong breeding hens were provided for a genome-wide association study, 27 SNPs respectively located in three genomic linkage regions (GGA1:41Kb; GGA3:39Kb and GGA8:39Kb) were suggested to be significantly associated with DF. Particularly, 6 of these 27 SNPs were further verified to be associated with DF in the 701 Jinghong and 408 Jingfen hens using PCR-RFLP genotyping method. These 27 SNPs were also mapped to 7 genes according to their genomic position. Furtherly, 5 of these 7 genes were tested using qPCR. Results show that the CYP2D6, WBP2NL, ESR1 and TGFBR3 mRNA expression levels of hens with long DF were significantly higher than the hens with short DF (P < 0.05). Overall, findings in our research provide new insight into the genetic basis of duration-of-fertility in breeding hens while providing new clues for further functional validation on the DF-related genetic regulation mechanism and improvement of DF through chicken breeding.
... Previous studies found that SS capacity is related to the surface area, epithelial cell height, and outer and inner diameters of the SSTs (Fan, 2020;Kheawkanha et al., 2021), consistent with the results of the present study. The SS capacity and number of SSTs are reportedly greater in turkeys than hens, suggesting that the number of SSTs varies in birds with different SS capacity (Bakst et al., 2010;Bakst and Bauchan, 2016). However, the results of the present study showed that although the number of SSTs was greater in the high SS group than the low SS group, the difference was not significant (P > 0.05). ...
The fertilization rate is an important index to evaluate the reproductive capacity of hens, which is mainly affected by semen quality, timing of artificial insemination (AI), and the ability to store sperm. A high sperm storage (SS) capacity can extend the interval, reduce the frequency, and decrease the labor costs of AI. However, relatively few studies have investigated the SS capacity of hens. Therefore, the aims of the present study were to identify factors influencing the SS capacity of Guangxi partridge chickens and to explore the impact of the sperm count in different sections of the oviduct and sperm storage tubules (SSTs), in addition to the number and surface area of SSTs on SS capacity at different time points after AI. We found that SS capacity was positively correlated to the egg production rate (P < 0.01) and body length (P < 0.05). On post-AI days 5, 10, and 15, the sperm count was higher in uterus-vagina junction (UVJ) than the magnum, isthmus, and infundibulum (P < 0.01), but gradually decreased over time. Also, the duration of SS and the sperm count of the UVJ was greater in the high SS group than the low SS group (P < 0.05). Histopathological analysis of the UVJ showed that the number and surface area of the SSTs (P < 0.01), as well as the proportion of SSTs containing sperm, were greater in the high SS group at all time points post AI (P < 0.01), while the proportion of SSTs containing sperm gradually decreased over time. Collectively, these results highlight the potential for selective breeding of SS capacity and show that SS capacity is related to laying performance and body length of Guangxi partridge hens. In addition, SS capacity was positively correlated to the surface area of SSTs and the proportion containing sperm. A greater sperm count stored in the UVJ was correlated to more sperm transported to the infundibulum and subsequent greater SS capacity of hens.
... The significant differences in the fertile periods observed between species have been related to changes in SST-specific sperm numbers and sperm storage capacity [37]. According to Bakst et al. [38], the biological basis of sustained fertility in chicken and turkeys is the ability of sperm to reside in SSTs. Differences in fertility duration in their study depended on the species, with that of domestic fowls (2-3 weeks) and turkeys (10-15 weeks) being related to their respective number of SSTs (4893 and 30,566 SSTs in chicken and turkeys, respectively). ...
Simple Summary
In chicken, sperm is transported through the cloaca to the uterovaginal junction, which consists of sperm storage tubules (SSTs) which store sperm for long periods and retain its fertilizing capacity. Declining fertility in old hens is speculated to be due to a higher sperm release rate from the SSTs of old hens compared to that of younger hens. To enhance older breeds’ fertility efficiency, the optimal number of sperm-per-insemination dose (150–250 × 10⁶ spz/dose) together with the insemination frequency (once, twice, and thrice weekly) and the morphological appearance of SSTs after insemination were explored in this study. The present study’s findings showed that the sperm concentration dosages did not influence fertility. The highest fertility rate was obtained through a thrice-weekly insemination frequency. The SST sperm content-related categories helped explain these results. The SST categories containing high levels of sperm decreased significantly in the once-weekly insemination group from day four onward. Meanwhile, only the thrice-weekly insemination group maintained a high sperm count in the SSTs throughout the week. In summary, an insemination dose of 150 × 10⁶ sperm was sufficient for fertilization, but a thrice-weekly insemination frequency was most appropriate for sustaining the fertility rate in aged Thai native hens.
Abstract
We aimed to evaluate the effects of sperm concentration (150–250 × 10⁶ spz/dose) and insemination frequency (once, twice, and thrice weekly) on fertility and sperm storage tubule (SST) characteristics. The SSTs were classified into five categories: namely, SSTs having an unscorable (SST1), empty (SST2), low (SST3), medium (SST4), and high (SST5) sperm count after insemination. The results showed that only insemination frequency affected the fertility rate (p < 0.05). The highest fertility was found in the thrice-weekly insemination group; however, this rate was not significantly different from that for the twice-weekly insemination group, except on day 7, while the once-weekly insemination group showed the lowest fertility rate (p < 0.05) from day four onward. On day 1, the SST characteristics showed no differences among the various insemination frequencies. On day 4, the SST2 and SST3 categories increased in the once-weekly insemination group (p < 0.05), while the SST4 and SST5 categories decreased compared to the twice- and thrice-weekly insemination groups (p < 0.05). On day 7, only the thrice-weekly insemination group maintained a level of SST5 category tubules like that measured on day 1 (p > 0.05). In summary, the insemination dose of 150 × 10⁶ sperm was enough for fertilization, and thrice-weekly insemination was the appropriate frequency in old Thai native hens for maintaining a high sperm density in the SSTs throughout the week.
... In avian species, duration of fertility from a single artificial insemination corresponds to the number and size of the SST present in the UVJ and varies across species. The turkey hen has been shown to possess up to 30,566 elongated SST, capable of storing sperm for up to 70 days compared to the domestic chicken, which has only up to 4,893 shorter SST, capable of storing sperm for only 21 days (Birkhead and Møller, 1992;Bakst et al., 2010). Despite stark differences in SST numbers between avian species correlated with duration of fertility, SST number does not differ between low fertility and high fertility hens within the same flock, indicating that SST functional differences are responsible for downstream differences in flock fertility rates. ...
Introduction: Sperm storage within the uterovaginal junction (UVJ) of avian species occurs in specialized structures termed sperm storage tubules (SSTs) and allows for prolonged storage of semen, though the molecular mechanisms involved in semen preservation are not well understood. Little work has been done examining how function of the SSTs is impacted by insemination and by semen present in the SSTs.
Methods: Transcriptome analysis was performed on isolated SSTs from turkey hens receiving no insemination (control), sham-insemination, or semen-insemination at three timepoints (D1, D30, and D90 post-insemination). Bioinformatic and functional annotation analyses were performed using CLC Genomics Workbench, Database for Annotation, Visualization, and Integrated Discovery (DAVID), and Ingenuity Pathway Analysis (IPA). Pairwise comparisons and k-medoids cluster analysis were utilized to decipher differential expression profiles in the treatment groups.
Results: The SST transcriptome of the semen inseminated group exhibited the greatest differences within the group, with differences detectable for up to 90 days post insemination, while control and sham-inseminated groups were more similar. In the semen-inseminated samples, upregulation of pathways relating to classical and non-classical reproductive signaling, cytoskeletal remodeling, physiological parameters of the local UVJ environment, and cellular metabolism was observed. In the sham-inseminated samples, upregulation of immune pathways and non-reproductive endocrine hormones was observed.
Discussion: This work provides insights into the molecular level changes of the SST in response to insemination as well as to the presence of semen. Results from this study may have direct implications on fertility rates as well as potential strategies for avian semen cryopreservation protocols.
... A diferencia de la hembra, que aumenta la producción de estradiol y progesterona con un diferencial significativo recién en septiembre, a fines de invierno, relacionado con el inicio de la postura de huevos. Los aparentes desfases reproductivos entre ambos sexos, desde el punto de vista hormonal, durante el inicio de la temporada, podrían explicarse por la capacidad de almacenamiento espermático que posee la hembra, capaz de mantener en su tracto a espermatozoides viables hasta por 70 días en los túbulos de almacenamiento espermático de la unión útero vaginal (Bakst et al., 1994;Bakst y Vinyard, 2002;Bakst et al., 2010). Las hembras son receptivas a la monta previo al inicio de la ovulación y consiguiente postura de huevos, período en que los túbulos de almacenamiento espermático son más eficientes, con mayor velocidad y volumen de carga espermática (Brillard y Bakst, 1990), ya sea por un proceso de selección espermática menos exigente en la región vaginal (Bakst y Akuffo, 2008) o por una menor dificultad de avance de los espermatozoides, al no encontrarse con huevos en procesos de formación al interior del oviducto (Zaniboni y Bakst, 2004). ...
... De manera general se puede establecer que el macho va finalizando su actividad de apareamiento a medida que la hembra reduce su receptividad estacional debido a los períodos de incubación y crianza (Tamai y Yoshimura, 2017), el aumento de las temperaturas ambientales (Sauveur, 1992) y la consecuente reducción en la calidad espermática (Noirault, et al., 2006a), mientras que la hembra reinicia su actividad ovulatoria, pero con la capacidad de conservar de forma viable los espermatozoides (Bakst et al., 1994;Bakst y Vinyard, 2002;Bakst et al., 2010) necesarios para asegurar la fertilidad de la siguiente etapa de incubación y crianza, para el segundo lote de pavipollos (Muñoz, 2019). Estos cambios estacionales en la actividad reproductiva, tienen como propósito biológico la maximización de la supervivencia de la descendencia, para que las crías nazcan y se desarrollen en condiciones ambientales donde el clima y la disponibilidad de alimentos sean favorables. ...
El fotoperiodo es una de las señales ambientales de mayor impacto sobre la estimulación reproductiva de las aves, actuando directamente sobre el eje hipotálamo-pituitario-gonadal, estimulando la producción de testosterona en el macho y estrógeno y progesterona en la hembra. Este estudio aborda el papel del fotoperiodo sobre las concentraciones plasmáticas de testosterona, estradiol y progesterona, en pavos criollos (Meleagris gallopavo) del Hemisferio Sur. Los resultados pueden contribuir a aclarar las relaciones entre la cantidad de horas de luz del fotoperiodo estacional y las temporadas con mayor potencial reproductivo. Los estudios se efectuaron entre julio y diciembre en Chillán, Región de Ñuble, Chile. Se emplearon 24 pavas y 16 pavos en un fotoperiodo natural, negativo de días cortos hacia uno positivo de días largos. Se efectuaron recolecciones mensuales de sangre, utilizando la fracción de suero para determinar las concentraciones hormonales mediante la técnica de RIA, empleando kits comerciales de acuerdo a las recomendaciones del fabricante. Existen diferencias significativas (p 0,05) en las concentraciones de estradiol, progesterona y testosterona a lo largo del ciclo reproductivo, con picos de estradiol, progesterona y testosterona coincidentes en los meses de septiembre y octubre, donde los aumentos de horas de luz diarias influyen significativamente (p 0,05) en la concentración plasmática. En conclusión, la etapa de fines de invierno e inicios de primavera es el período de mayor interés reproductivo para la especie en los sistemas de crianza de traspatio en el hemisferio sur, favoreciendo el desarrollo de programas de conservación y reproducción.
... This difference in the production cycle between the two species may indicate distinct mechanisms of reproductive tract development, maintenance, and regression. Additionally, sperm storage capacity and duration in the SSTs can vary significantly among avian species (Birkhead and Møller, 1992), and there is a substantial difference in the number of SSTs observed between chicken and turkey breeders (Bakst et al., 2010). ...
Artificial insemination is a standard practice in the turkey breeder industry to ensure the production of fertile eggs. Even though hens are inseminated on a weekly basis, their fertility tends to decline after a few weeks of production. Avian species have a specialized structures called sperm storage tubules (SSTs), located in the uterovaginal junction (UVJ) of the oviduct. The ability of SSTs to store sperm is directly correlated with the fertility of the hen. The objective of the study was to examine changes in the transcriptome of the turkey hen’s UVJ in response to the presence of sperm at three key stages of production. We hypothesized that repeated and prolonged exposure to sperm would alter the transcriptome of the UVJ. Samples were collected from virgin hens prior to the onset of lay, as well as from sham-inseminated (extender only) and semen-inseminated hens at early lay, peak lay, and late lay. Gene expression profiling of the UVJ was examined, and a differential expression analysis was conducted through pairwise comparisons between semen- and sham-inseminated groups at each production stage and across production stages. In the early laying stage, no significant gene expression changes were found between semen- and sham-inseminated groups. However, at peak lay, genes related to lipid biosynthesis, Wnt signaling, cell proliferation, and O-glycan biosynthesis were upregulated in the semen group, while the immune response and cytokine-cytokine receptor interaction were downregulated. In the late lay stage, the transcription pathway was upregulated in the semen group, whereas the translation pathway was downregulated. The local immune response that was suppressed during peak lay was increased at the late laying stage. In the semen-inseminated group, the UVJ exhibited advanced aging at the late laying stage, evidenced by reduced telomere maintenance and translation processes. The results from this study provide valuable insights into the alteration of the UVJ function in response to the presence of sperm at different stages of production and throughout the production cycle. Targeting the modulation of local immune response and addressing aging processes after peak production could potentially prevent or delay the decline in fertility of turkey breeder hens.
... Our data revealed that semen containing 2% glycerol showed a noticeable decrease in its ability to colonize the SST, while 6% glycerol resulted in the absence of sperm in the SST. This decrease or absence of sperm in SST, as previously mentioned (Bakst et al., 2010;Hemmings et al., 2015), is certainly one of the major causes of reduced fertility induced by the presence of glycerol. However, this experiment did not determine whether the absence of sperm in the SST was due to a failure of sperm migration from the vagina to the SST or a failure of sperm entering and binding to the SST. ...
... The quality of the inseminated spermatozoa and the number of sperm storage tubules (SST) at the utero vaginal junction (UVJ) can be factors for successful fertilization. Bakst et al. (2010); Birkhead and Brillard (2007) concluded that the main causes of fertilization failure in poultry are the ability of spermatozoa to reach the SST, failure of spermatozoa to enter or leave the SST, the ability of spermatozoa to reach a fertilization site in the infundibulum and the ability of spermatozoa to penetrate the ovum. This could be caused by the quality of the inseminated spermatozoa. ...
... This could be caused by the quality of the inseminated spermatozoa. In addition, the number of SSTs also correlates with the fertile period and duration of fertilization (Bakst et al., 2010). It was further explained that the number of SSTs determines the storage capacity of spermatozoa in the female reproductive tract. ...
... Although females are capable of storing sperm and fertilizing the ovum, there is still a significant fertility difference between or within species. For example, in the breeding of laying hens, the storage duration of sperm is more than 15 d, whereas the short one is less than 3 d after artificial insemination (Bakst et al., 2010;Yang et al., 2022). Several studies have suggested that the morphological differences in adult UVJ folds (containing SSTs) were the key factor responsible for the differences in sperm storage duration (Pierson et al., 1988;Adetula et al., 2018;Wen et al., 2020;Yang et al., 2021a). ...
The development regulation of the uterine-vaginal junction (UVJ) epithelial folds during the sexual maturation of female birds played crucial roles in the adults' sperm storage duration and fertilization capability. However, there is a lack of studies on it in the breeding field of laying hens. In this study, White Leghorn was used for the morphological and developmental studies. According to the morphological characteristics, the development of the UVJ epithelial folds was classified into 4 stages (morphological stage T1-T4). Significant individual differences were observed simultaneously, which is one of the factors leading to the adults' UVJ morphological differences. Bulk RNA-seq suggested the different regulations of UVJ epithelial folds were classified into 3 stages (developmental stage S1-S3). Genes enriched in cell proliferation, differentiation, polarity, migration, adhesion and junction were supposed to regulate UVJ epithelial fold formation. Single-cell RNA-sequencing (scRNA-seq) showed significant differences between different types of cells within UVJ at the developmental stage S2. Immunohistochemical studies confirmed that the different proliferation rates between the epithelium and nonepithelium were one of the key factors leading to the formation of UVJ epithelial folds. Genes in the TGF-beta and WNT pathways may play roles in regulating the proliferation and differentiation of epithelium. Some factors, such as CHD2, CDC42, and carbonic anhydrases, were important participants in forming UVJ epithelial folds. This study will provide new thoughts on the differential regulation of fertilization traits from the developmental biology perspective.
