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The ovary is a crucial reproductive organ in mammals, and its development directly influences an individual's sexual maturity and reproductive capacity. To comprehensively describe ovarian sexual maturation in goats, we integrated phenotypic, hormonal, metabolomic, and transcriptomic data from four specific time points: after birth (D1), at 2 months old (M2), at 4 months old (M4), and at 6 month old (M6). The study showed that during the early stage (D1–M2), ovarian growth was the most rapid, with weight and morphology increasing by 284% and 65%, respectively, and hormone levels rose significantly, with estradiol increasing by 57%. Metabolomic analysis identified 1231 metabolites, primarily lipids, lipid molecules, and organic acids, which can support hormone balance and follicle development by providing energy and participating in signaling transduction. Transcriptomic analysis identified 543 stage-specific differentially expressed genes, mainly enriched in steroid biosynthesis, amino acid metabolism, and the PI3K/AKT pathway, which are key factors influencing ovarian cell proliferation, apoptosis, hormone secretion, and metabolism. The integrated analysis revealed the key processes in the ovarian steroid hormone biosynthesis pathway and gene/metabolite networks associated with ovarian phenotypes and hormone levels, ultimately highlighting scavenger receptor class B type 1 (SCARB1), Cytochrome P450 Family 1 Subfamily A Member 1 (CYP11A1), 3beta-hydroxysteroid dehydrogenase (3BHSD), progesterone, estradiol, and L-phenylalanine as key regulators of ovarian morphological and functional changes at different developmental stages. This study is the first to reveal the metabolic changes and molecular regulatory mechanisms during ovarian sexual maturation in goats, providing valuable insights for understanding reproductive system development and optimizing reproductive performance and breeding efficiency. [ABSTRACT FROM AUTHOR]

To investigate the reproductive behavior of the frigate tuna (Auxis thazard) along the North Atlantic coast of Morocco, a comprehensive study was conducted between February and October 2020. A total of 215 frigate tuna specimens, obtained from both artisanal fishery and commercial purseseiners, were meticulously examined on a monthly basis. The study focused on evaluating various reproductive parameters including sex ratio, condition factor (K), gonadosomatic index (GSI), and sexual maturity progression. The findings of this study revealed that the straight fork lengths of the frigate tuna ranged from 30 to 43cm. Analysis of the sex ratio indicated a slight dominance of females, with a ratio of 1.06 females to every male (observed sex ratio: 1:0.06; X² observed = 1.21, which was below the theoretical X² = 3.84 threshold at P< 0.05). The size at which individuals reached sexual maturity (FL 50) was estimated to be 36cm for females and 38cm for males. Through monthly assessments, it was observed that the variation in maturity stages, GSI, and K values suggested a spawning period predominantly occurring between June and August, with a peak in July. This temporal pattern underscores the importance of understanding the reproductive dynamics of the frigate tuna populations in this region. [ABSTRACT FROM AUTHOR]

The reproductive strategies of species play a fundamental role in formulating effective management plans and maintaining local community structure and ecological balance. This study investigated the reproductive characteristics of two sympatric species, Callinectes danae and Callinectes ornatus, in Atlantic waters. Monthly sampling was conducted from July/12 to June/14 in the coastal (sites: S1, S2, S3 and S4) and estuarine-lagoon (sites: S5, S6 and S7) areas of Cananéia-Iguape, Brazil. Significant differences in allometric coefficients were observed, particularly in the relationships chelipod length vs. carapace width (CW) for males and abdominal width vs. carapace width (CW) for females. Morphological sexual maturity was estimated at 58.8 mm CW for C. danae males, 54.5 mm CW for females, 45.0 mm CW for C. ornatus males, and 41.2 mm CW for females. Gonadal sexual maturity sizes were identified at 69.4 mm CW for C. danae males, 61.4 mm CW for females, and 58.4 mm CW for C. ornatus males, 46.9 mm CW for females. Both species spawn predominantly during the austral summer, with higher prevalence in site S5 for C. danae and S1 for C. ornatus. Recruitment occurred in austral spring and summer, with C. danae concentrated in estuarine-lagoon regions and C. ornatus along the coast. Reproductive patterns of C. danae were associated with temperature and salinity, while C. ornatus exhibited correlations with temperature and organic matter. This study highlights the influence of environmental factors on species' life cycles. Furthermore, it contributes to the evaluation of management and monitoring strategies, recognizing the economic and ecological significance of these species for sustaining these ecosystems. [ABSTRACT FROM AUTHOR]

Background: Understanding sexual maturity and bone fusion is crucial in forensic investigations and legal contexts. This study investigates the contemporary trend of sexual maturity and bone fusion in females, comparing the observed age-related characteristics with documented ages. Such analyses contribute to the accuracy of age estimation methods used in medico-legal scenarios. Methods: A comprehensive study was conducted involving a diverse sample of females, and their sexual maturity and bone fusion were assessed relative to documented ages. The research utilized a cross-sectional design, collecting data through interviews, medical examinations, and radiographic imaging. Ethical approval was obtained, and participants provided informed consent. Variables included documented age, age of menarche, stages of sexual maturity, dentition, and bone fusion. Validation of model performance was conducted. Results: Among 70 cases studied, the mean age of menarche was 10.48 years (range: 7–12 years). Maternal reports indicated menarche onset between 12–17 years. Tanner’s Staging 5 for pubic hair and fully developed breasts occurred at 14 years. Permanent teeth increased with age, with 28 or more teeth present at age 14 or above. Fusion of the distal end of the Radius and Ulna with the parent bone was positive from 15 years onwards. The regression model predicted age accurately (97.99% fit). Conclusion: The results highlight the early onset of sexual maturation, consistent teeth eruption, and bone fusion patterns in females. The observed correlations offer valuable insights for medicolegal practitioners and forensic experts.

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Copyright of Bulletin de la Societe Zoologique de France is the property of Societe Zoologique de France and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigated the biology, population parameters, and ecology of the sergestid shrimp (Acetes) in Barangay Damilisan, Miagao, Iloilo, the Philippines, by collecting samples for biological analyses and analyses using FiSAT II software. Based on morphometric evaluation, the sergestid shrimps present in the study site were identified as Acetes intermedius. Mature and near-spawning of the 180 specimens examined for ovarian maturity were > 50% in January, February, and April 2022. Size at sexual maturity was recorded at lengths ranging from 21.90-23.10 mm. The highest mean TL and CL were 20.49 ± 1.84 and 5.32 ± 0.56 mm, respectively, in January 2022. The length-frequency data showed that the highest frequency was 18.50-20.40 mm. The male-to-female sex ratio was 1:2; wherein females dominated the males. The highest frequency for females ranged from 20.50-22.40 mm (TL). Estimated population parameters of A. intermedius were L∞ = 30.98 mm, K = 1.900 yr-1, Ø' =3.26 yr-1, tmax= 1.6 yr-1, M = 3.93 yr-1, F = 4.07 yr-1, Z = 8.00 yr-1, E = 0.51, E0.1 = 0.517, E0.5 = 0.349, Emax = 0.691, L50%/Lc = 13.45 mm, and L75% = 14.57 mm with a unimodal type of recruitment pattern. The value obtained for the exploitation rate was above 0.5, hence suggesting that the Acetes stocks in Brgy. Damilisan faced overexploitation. These results provide information that can be used to properly conserve, utilize, and manage the Acetes fishery industry in Miagao, Iloilo, the Philippines. [ABSTRACT FROM AUTHOR]

Abstract Background Bacteriophages are prokaryotic viruses that rank among the most abundant microbes in the gut but remain among the least understood, especially in quails. In this study, we surveyed the gut bacteriophage communities in 22 quails at different ages (days 20 and 70) using shotgun metagenomic sequencing. We then systematically evaluated the relationships with gut bacteria and host serum metabolites. Results We discovered that Myoviridae and Siphoviridae were the dominant bacteriophage families in quails. Through a random forest and LEfSe analysis, we identified 23 differential bacteriophages with overlapping presence. Of these, 21 bacteriophages (e.g., Enterococcus phage IME-EFm5 and Enterococcus phage IME-EFm1) showed higher abundances in the day 20 group, while two bacteriophages (Bacillus phage Silence and Bacillus virus WPh) were enriched in the day 70 group. These key bacteriophages can serve as biomarkers for quail sexual maturity. Additionally, the differential bacteriophages significantly correlated with specific bacterial species and shifts in the functional capacities of the gut microbiome. For example, Enterococcus phages (e.g., Enterococcus phage EFP01, Enterococcus phage IME-EFm5, and Enterococcus phage IME-EFm1) were significantly (P 0.05, FDR) correlated with nicotinamide riboside and triacetate lactone. In contrast, some differential bacterial species (e.g., Christensenella massiliensis and Bacteroides neonati) significantly (P

The mammalian pituitary gland drives highly conserved physiological processes such as somatic cell growth, pubertal transformation, fertility, and metabolism by secreting a variety of hormones. Recently, single-cell transcriptomics techniques have been used in pituitary gland research. However, more studies have focused on adult pituitary gland tissues from different species or different sexes, and no research has yet resolved cellular differences in pituitary gland tissue before and after sexual maturation. Here, we identified a total of 15 cell clusters and constructed single-cell transcriptional profiles of rats before and after sexual maturation. Furthermore, focusing on the gonadotrope cluster, 106 genes were found to be differentially expressed before and after sexual maturation. It was verified that Spp1, which is specifically expressed in gonadotrope cells, could serve as a novel marker for this cell cluster and has a promotional effect on the synthesis and secretion of follicle-stimulating hormone. The results provide a new resource for further resolving the regulatory mechanism of pituitary gland development and pituitary hormone synthesis and secretion. [ABSTRACT FROM AUTHOR]

BACKGROUND: Development of accurate pest monitoring systems is essential for the establishment of integrated pest management strategies. Information about the pest behavior during the colonization process, as well as the sex and reproductive status of the colonizing population often are lacking and hinder their development. The cabbage stem flea beetle (CSFB, Psylliodes chrysocephala) can cause the complete destruction of oilseed rape crops (OSR, Brassica napus). In the present study, the colonization process of OSR fields by the CSFB was studied. RESULTS: More individuals were caught on the outward facing side of the traps than the side of the trap facing towards the crop at the field border and catches were higher on the trapping units at the center of the field than at its border, suggesting that more beetles were entering than leaving the crop. Catches were higher on lower traps placed near to the crop than on those positioned further from the ground and also were higher during the day than late afternoon and night. The sex‐ratio of individuals caught was skewed towards males and sexual maturity was acquired for females during the experiment. Integration of sampling data with local meteorological data showed that the catches correlated mostly with air temperature and relative humidity. CONCLUSION: This study provides new information about the dispersion of the CSFB in OSR fields during the colonization process, and highlights correlations between local meteorological factors and activity of the CSFB, and represent a new step towards implementing monitoring strategies against this pest. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The striped mullet Mugil cephalus is a species of high commercial value with a spawning season that spans from autumn to winter in coastal areas of the northern Gulf of Mexico. The objective of this project was to study an annual cycle of monthly stages of M. cephalus sexual maturity in two southern Gulf of Mexico localities during 2018, to compare results with those reported for the rest of the Gulf of Mexico, and to analyze the spawning temporality vs. tidal oscillations. Specimens were obtained monthly (January–December 2018) from commercial captures collected in Alvarado Lagoon, Veracruz and Puerto Ceiba, Tabasco. Total length, standard length, and total weight were recorded after the fish were eviscerated and the gonads were separated, and sex, eviscerated weight, gonad weight, and the stage of sexual maturity were recorded. A Gonadosomatic Index was obtained, and the gonads with vitellogenetic development were observed to determine the spawning season. M. cephalus spawns simultaneously in both localities, together with virtually synchronous spawning throughout the Gulf of Mexico, from October to March in northern localities and from December to January in southern areas of the Gulf of Mexico. Meteorological tides produced by the "northers" throughout the Gulf of Mexico seem to trigger spawning migrations. The synchronous spawning of M. cephalus supports the evidence that this is a panmictic population in the Gulf of Mexico. [ABSTRACT FROM AUTHOR]

Background: Bacteriophages are prokaryotic viruses that rank among the most abundant microbes in the gut but remain among the least understood, especially in quails. In this study, we surveyed the gut bacteriophage communities in 22 quails at different ages (days 20 and 70) using shotgun metagenomic sequencing. We then systematically evaluated the relationships with gut bacteria and host serum metabolites. Results: We discovered that Myoviridae and Siphoviridae were the dominant bacteriophage families in quails. Through a random forest and LEfSe analysis, we identified 23 differential bacteriophages with overlapping presence. Of these, 21 bacteriophages (e.g., Enterococcus phage IME-EFm5 and Enterococcus phage IME-EFm1) showed higher abundances in the day 20 group, while two bacteriophages (Bacillus phage Silence and Bacillus virus WPh) were enriched in the day 70 group. These key bacteriophages can serve as biomarkers for quail sexual maturity. Additionally, the differential bacteriophages significantly correlated with specific bacterial species and shifts in the functional capacities of the gut microbiome. For example, Enterococcus phages (e.g., Enterococcus phage EFP01, Enterococcus phage IME-EFm5, and Enterococcus phage IME-EFm1) were significantly (P < 0.001, FDR) and positively correlated with Enterococcus faecalis. However, the relationships between the host serum metabolites and either bacteriophages or bacterial species varied. None of the bacteriophages significantly (P > 0.05, FDR) correlated with nicotinamide riboside and triacetate lactone. In contrast, some differential bacterial species (e.g., Christensenella massiliensis and Bacteroides neonati) significantly (P < 0.05, FDR) correlated with nicotinamide riboside and triacetate lactone. Furthermore, characteristic successional alterations in gut bacteriophages, bacteria, and host serum metabolites across different ages highlighted a sexual maturity transition coexpression network. Conclusion: This study improves our understanding of the gut bacteriophage characteristics in quails and offers profound insights into the interactions among gut bacteriophages, bacteria, and host serum metabolites during the quail's sexual maturity transition. [ABSTRACT FROM AUTHOR]

Abstract Aspects of the reproductive biology of Donax striatus were studied from individuals collected from Gado Bravo Beach in the municipality of Tibau do Norte, state of Rio Grande do Norte, Brazil. Donax striatus is a dioic species without external (on the shell) or internal (gonads) macroscopic dimorphism. Thus, a microscopic examination of the reproductive cells is necessary. For the characterization of the gonadal development stages and determination of the size at first sexual maturity (L50), 30 specimens were selected monthly between February 2021 and January 2022 and submitted to histological processing. The condition index (CI) of each individual was estimated and monthly variations were statistically assessed. The size at first maturity (L50) was estimated to be 14.2 mm in shell length. To foster conservation of the species, catches of individuals larger than 14.2 mm is recommended. The lowest condition indices were found in the dry season, with a greater occurrence of organisms in the elimination stage and exhibiting gonad tissue reorganization. Higher indices were found in the rainy season, with the presence of mature individuals. The continuous nature of gametogenesis in Donax stritatus reflects the influence of rainfall in the region. Males and females have peak gamete elimination with pauses during the year, but with the presence of maturing and eliminating individuals throughout the year. As shellfish gathering targeting Donax striatus is excessive on Gado Bravo Beach in the state of Rio Grande do Norte, it is hoped that the results of the present study can contribute to the establishment of management measures for the activity and conservation strategies for the species.

Abstract Background The sexual maturity of chickens is an important economic trait, and the breeding of precocious and delayed puberty roosters is an important selection strategy for broilers. The comb serves as an important secondary sexual characteristic of roosters and determines their sexual precocity. Moreover, comb development is closely associated with gonad development in roosters. However, the underlying molecular mechanism regulating the sexual maturity of roosters has not yet been fully explored. Results In order to identify the genes related to precocious puberty in Qingyuan partridge roosters, and based on the synchrony of testis and combs development, combined with histological observation and RNA-seq method, the developmental status and gene expression profile of combs and testis were obtained. The results showed that during the early growth and development period (77 days of age), the development of combs and testis was significant in the high comb (H) group versus the low comb (L) group (p

Abstract Background The ovary is an important reproductive organ in mammals, and its development directly affects the sexual maturity and reproductive capacity of individuals. MicroRNAs (miRNAs) are recognized as regulators of reproductive physiological processes in various animals and have been shown to regulate ovarian development through typical targeting and translational repression. However, little is known about the regulatory role of miRNAs in ovarian tissue development during sexual maturity in goats. To comprehensively profile the different physiological stages of sexual maturation in goats, we performed small-RNA sequencing of ovarian tissue samples collected at four specific time points (1 day after birth (D1), 2 months old (M2), 4 months old (M4), and 6 months old (M6)). In addition, we used ELISAs to measure serum levels of reproductive hormones to study their temporal changes. Results The results showed that serum levels of gonadotropin-releasing hormone, follicle-stimulating hormone, luteinizing hormone, oestradiol, progesterone, oxytocin, and prolactin were lower in goats at the D1 stage than at the other three developmental stages (P 1, FDR

The ovary is a crucial reproductive organ in mammals, and its development directly influences an individual’s sexual maturity and reproductive capacity. To comprehensively describe ovarian sexual maturation in goats, we integrated phenotypic, hormonal, metabolomic, and transcriptomic data from four specific time points: after birth (D1), at 2 months old (M2), at 4 months old (M4), and at 6 month old (M6). The study showed that during the early stage (D1–M2), ovarian growth was the most rapid, with weight and morphology increasing by 284% and 65%, respectively, and hormone levels rose significantly, with estradiol increasing by 57%. Metabolomic analysis identified 1231 metabolites, primarily lipids, lipid molecules, and organic acids, which can support hormone balance and follicle development by providing energy and participating in signaling transduction. Transcriptomic analysis identified 543 stage-specific differentially expressed genes, mainly enriched in steroid biosynthesis, amino acid metabolism, and the PI3K/AKT pathway, which are key factors influencing ovarian cell proliferation, apoptosis, hormone secretion, and metabolism. The integrated analysis revealed the key processes in the ovarian steroid hormone biosynthesis pathway and gene/metabolite networks associated with ovarian phenotypes and hormone levels, ultimately highlighting scavenger receptor class B type 1 (SCARB1), Cytochrome P450 Family 1 Subfamily A Member 1 (CYP11A1), 3beta-hydroxysteroid dehydrogenase (3BHSD), progesterone, estradiol, and L-phenylalanine as key regulators of ovarian morphological and functional changes at different developmental stages. This study is the first to reveal the metabolic changes and molecular regulatory mechanisms during ovarian sexual maturation in goats, providing valuable insights for understanding reproductive system development and optimizing reproductive performance and breeding efficiency.

Simple Summary: The golden takin (Budorcas taxicolor bedfordi) is an endangered animal. While information on this species' reproductive physiology is essential for its conservation, endocrinological studies are limited. Monitoring fluctuations in fecal sex steroid hormones is known to be a useful means of understanding reproductive physiological states such as pregnancy and estrus. In this study, we measured the concentrations of sex steroid hormone metabolites excreted in the feces of female golden takins and used the long-term fluctuations to determine their endocrine ovarian activity. This study indicates that the monitoring of fecal sex steroid hormone concentrations can be used to understand estrus and pregnancy and predict delivery. This study investigates the non-invasive monitoring of the endocrine ovarian activities of captive female golden takins (Budorcas taxicolor bedfordi) based on long-term fecal sex steroid hormone metabolite dynamics. Fecal progesterone (P4) metabolite dynamics were monitored in nine females for 0.5–15 years between 2004 and 2022. Fecal estradiol-17β (E2) and estrone (E1) metabolites were measured during certain estrous cycles, and fecal E1 metabolite concentrations were measured during all gestation periods. The breeding season of the captive animals was mainly between May and December, and they were polyestrous animals whose breeding season begins during the long-day period. The onset of the breeding season occurred slightly earlier as age increased. The mean age (±SD) at puberty based on fecal P4 metabolite dynamics was 4.1 ± 2.9 years. The first conception ages ranged from 2.3–10.2 years. The mean estrous cycle period (±SEM) was 25.4 ± 1.1 days, and mounting and mating occurred in periods of low fecal P4 metabolite levels during the breeding season. The mean gestation period (±SD) from the estimated mating date to the calving date was 253.9 ± 5.7 days, and the fecal P4 metabolite distribution during pregnancy was bimodal. Fecal estrone metabolite levels gradually increased 21 weeks before delivery, peaked during the week of delivery, and then markedly decreased in the first week after delivery. Estrus resumed in the first April–August period after delivery (mean ± SD; 103.5 ± 40.9 days) or in May of the year after delivery (421.0 ± 16.5 days). This study revealed that the estrous cycle and pregnancy of female golden takins can be determined by fecal progesterone metabolite dynamics and that fecal estrone metabolite dynamics increases toward parturition and are useful for predicting the date of delivery. This endocrinological information is important for planned breeding efforts for the golden takins. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the relationship carapace width and body weight, condition factor, sex ratio, stage of gonad maturity, first sizesexual maturity, and fecundity in the Kolono Bay. Crab samples were obtained using folding trap fishing gear. The resultas of this study were that distribution of carapace width and body weight of male and ovigerou female T. crenata tended to be greater than that of females. While thecarapace width and body weight of female T. crenata tended to be smaller than body size of thecorrelation between carapace width and body weight of T. crenatashows a very shows a strong andpositive relationship with negative allometric growth patterns. . Male condition factors were significantlydifferent (p <0.05) from ovigerous females and females. Male and female condition factors weresignificantly different (p <0.05) indicating that the male was greater than the female. Overall sex ratiowas significantly different (p <0.05) from the 1: 1 ratio, except in the period July and August. Gonadmaturity stages based on sex and ovigerous females were found to vary during research but weredominated by the mature of gonads. The carapace width of the first sexual maturity this crab, male and female, were 55.39mm and 49.53 mm, respectively with fecundity ranged from 32.741 to 257.798. [ABSTRACT FROM AUTHOR]

Age at sexual maturity is a key life history trait that can be used to predict population growth rates and develop life history models. In many wild animal species, the age at sexual maturity is not accurately quantified. This results in a reduced ability to accurately model demography of wild populations. Recent studies have indicated the potential for CpG density within gene promoters to be predictive of other life history traits, specifically maximum lifespan. Here, we have developed a machine learning model using gene promoter CpG density to predict the mean age at sexual maturity in mammalian species. In total, 91 genomes were used to identify 101 unique gene promoters predictive of age at sexual maturity across males and females. We found these gene promoters to be most predictive of age at sexual maturity in females (R2 = 0.881) compared to males (R2 = 0.758). The median absolute error rate was also found to be lower in females (0.427 years) compared to males (0.785 years). This model provides a novel method for species‐level age at sexual maturity prediction without the need for long‐term monitoring. This study also highlights a potential epigenetic mechanism for the onset of sexual maturity, indicating the possibility of using epigenetic biomarkers for this important life history trait. [ABSTRACT FROM AUTHOR]

When applied at growing phase, lighting program aims to obtain quails with body weight and physiological maturity suitable for the beginning of laying. This study evaluated lighting programs at growing phase on performance, sexual maturity and egg quality of meat quail breeders (Coturnix coturnix) at laying phase. From 7 to 49 days of age, 300 female meat quails were subjected to three lighting programs (natural, intermittent and continuous), with 5 replicates of 20 birds each. At 49 days of age, 240 quails were transferred to a shed, maintaining the same experimental conditions. Meat quails submitted to continuous and intermittent lighting programs had higher weight of reproductive system and lower ages for first egg production and to reach 50% of egg production (P < 0.05). Quails submitted to natural lighting had lower feed intake from 49 to 70 and 71 to 92 days of age and worse feed conversion up to 114 days of age. Continuous and intermittent lighting programs resulted in more precocious quails compared to natural lighting program. Quails submitted to natural lighting at growing phase presented lower egg production during all periods, not differing for birds submitted to continuous and intermittent programs from the second period (71 to 92 days of age). Intermittent and continuous lighting result in better feed conversion of breeding quails up to 114 days and a higher percentage of laying (49 to 136 days), reducing the number of days to produce the first egg and to reach 50% of laying, in relation to natural lighting. [ABSTRACT FROM AUTHOR]

Simple Summary: Galaxias maculatus plays an important ecological and socioeconomic role in Chile. We determine the sex ratio, sexual maturity stages, gonadosomatic index, spawning period, type and frequency of spawning, and fecundity under experimental culture. The sex ratio was close to 1:1. First sexual maturity was reached at one year of age in 50% of the population. The highest GSI in both females and males was found in August. Nevertheless, females have a long spawning period, divided into two subperiods; the highest reproductive peak occurs between September and October, and the minor peak occurs between December and February. The females spawned between 3 and 10 times over a period of two months. The number of embryos per female per day varied from 1 to 429, while the total number of embryos per female during the entire season varied from 163 to 1044. This knowledge will be useful to establish future reproductive programs in captivity as a strategy for sustainable fishery and aquaculture management. This study determines the reproductive patterns of puye (Galaxias maculatus) under culture conditions. A population of 567 wild fish was caught in the Cautín River, Chile, and held in captivity for four years. Mortality, sex ratio, gonadosomatic index (GSI), sexual maturity stages, spawning period, type and frequency of spawning, and fecundity were measured. The fish grew throughout the experimental period, with the fastest rate during the first half of the first year of life. The highest mortality occurred during the first three months of the experiment and during the spawning season. The sex ratio was almost 1:1 (female:male). First sexual maturity was reached at one year of age, with an average weight of 0.85 ± 0.01 g, total length of 4.85 ± 0.16 cm, and condition factor 0.0074. The highest GSI in both females (12.14 ± 0.74) and males (17.7 ± 2.70) was recorded in August. Nevertheless, the females spawned 3 to 10 times between September and February, with the highest reproductive peak between September and October. The number of embryos per female per day varied from 1 to 429, while the total number of embryos per female during the entire season evaluated varied from 163 to 1044. There was a high correlation (r = 0.82) between absolute fecundity and body weight. Although further studies are needed in this field, these results are basic for establishing future reproductive programs in captivity as a strategy for sustainable fisheries and aquaculture management. [ABSTRACT FROM AUTHOR]

Background: The sexual maturity of chickens is an important economic trait, and the breeding of precocious and delayed puberty roosters is an important selection strategy for broilers. The comb serves as an important secondary sexual characteristic of roosters and determines their sexual precocity. Moreover, comb development is closely associated with gonad development in roosters. However, the underlying molecular mechanism regulating the sexual maturity of roosters has not yet been fully explored. Results: In order to identify the genes related to precocious puberty in Qingyuan partridge roosters, and based on the synchrony of testis and combs development, combined with histological observation and RNA-seq method, the developmental status and gene expression profile of combs and testis were obtained. The results showed that during the early growth and development period (77 days of age), the development of combs and testis was significant in the high comb (H) group versus the low comb (L) group (p < 0.05); however, the morphological characteristic of the comb and testicular tissues converged during the late growth and development period (112 days of age) in the H and L groups. Based on these results, RNA-sequencing analysis was performed on the comb and testis tissues of the 77 and 112 days old Qingyuan Partridge roosters with different comb height traits. GO and KEGG analysis enrichment analysis showed that the differentially expressed genes were primarily enriched in MAPK signaling, VEGF signaling, and retinol metabolism pathways. Moreover, weighted correlation network analysis and module co-expression network analysis identified WNT6, AMH, IHH, STT3A, PEX16, KPNA7, CATHL2, ROR2, PAMR1, WISP2, IL17REL, NDRG4, CYP26B1, and CRHBP as the key genes associated with the regulation of precocity and delayed puberty in Qingyuan Partridge roosters. Conclusions: In summary, we identified the key regulatory genes of sexual precocity in roosters, which provide a theoretical basis for understanding the developmental differences between precocious and delayed puberty in roosters. [ABSTRACT FROM AUTHOR]

The lumptail searobin (Prionotus stephanophrys Lockington 1881) is one of the most captured species as part of the bycatch in hake fishing operations; therefore, this research analyzed the size-weight relationship, gonadosomatic index, and size at sexual maturity of 622 individuals incidentally captured by the polyvalent fishing fleet between 2017 and 2018 in the Ecuadorian coast, where it was observed that the most frequent lengths were 27-28 cm TL for both sexes, with an average length for females of 27.73 ± 2.88 cm LT and for males of 26.78 ± 2.51 cm LT; however, in general, no significant differences were found in size structure in combined years (P>0.05). Additionally, the estimated size at sexual maturity was 20.22 cm; therefore, it is considered that all incidentally captured individuals are above sexual maturity, with only 3.86% below it. The total length-total weight relationship showed for the species a negative allometric growth; meanwhile, the gonadosomatic index established that the reproductive season corresponds from march to november, and from april to may is resting season. The highest incidental capture of individuals, especially females, coincided with the peak of reproductive intensity, with a sex ratio F:M of 1.5:1. [ABSTRACT FROM AUTHOR]

Background: The ovary is an important reproductive organ in mammals, and its development directly affects the sexual maturity and reproductive capacity of individuals. MicroRNAs (miRNAs) are recognized as regulators of reproductive physiological processes in various animals and have been shown to regulate ovarian development through typical targeting and translational repression. However, little is known about the regulatory role of miRNAs in ovarian tissue development during sexual maturity in goats. To comprehensively profile the different physiological stages of sexual maturation in goats, we performed small-RNA sequencing of ovarian tissue samples collected at four specific time points (1 day after birth (D1), 2 months old (M2), 4 months old (M4), and 6 months old (M6)). In addition, we used ELISAs to measure serum levels of reproductive hormones to study their temporal changes. Results: The results showed that serum levels of gonadotropin-releasing hormone, follicle-stimulating hormone, luteinizing hormone, oestradiol, progesterone, oxytocin, and prolactin were lower in goats at the D1 stage than at the other three developmental stages (P < 0.05). The secretion patterns of these seven hormones show a similar trend, with hormone levels reaching their peaks at 4 months of age. A total of 667 miRNAs were detected in 20 libraries, and 254 differentially expressed miRNAs and 3 groups of miRNA clusters that had unique expression patterns were identified (|log2-fold change|> 1, FDR < 0.05) in the 6 comparison groups. RT‒qPCR was employed to confirm that the expression pattern of the 15 selected miRNAs was consistent with the Illumina sequencing results. Gene ontology analyses revealed significant enrichment of GO terms such as cell proliferation regulation, epithelial cell development, and amino acid transport, as well as important signaling pathways including the MAPK signaling pathway, the PI3K-Akt signaling pathway, and the oestrogen signaling pathway. Further miRNA‒mRNA regulation network analysis revealed that 8 differentially expressed miRNAs (chi-miR-1343, chi-miR-328-3p, chi-miR-877-3p, chi-miR-296-3p, chi-miR-128-5p, chi-miR-331-3p, chi-miR-342-5p and chi-miR-34a) have important regulatory roles in ovarian cell proliferation, hormone secretion and metabolism-related biological processes. Conclusions: Overall, our study investigated the changes in serum hormone and miRNA levels in the ovaries. These data provide a valuable resource for understanding the molecular regulatory mechanisms of miRNAs in ovarian tissue during the sexual maturity period in goats. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the growth and spawning characteristics of wild Channa lucius (Cuvier, 1831) populations in the Mekong Delta, Vietnam. The study was carried out from March 2011 to February 2012. The length–weight relationship of C. lucius was determined according to the equations W = 0.0044L3.2494, R2 = 0.9157 (female fish) and W = 0.0047L3.2178, R2 = 0.9434 (male fish). The length and weight of the body for female fish ranged from 16.3 to 36.0 cm and 49.0 to 550.0 g, and for male fish, from 14.6 to 38.2 cm and 46.0 to 639.0 g, respectively. Female and male fish had almost similar lengths at first maturity (21.3958 cm for females and 21.3952 cm for males). The condition factor of female fish ranged from 0.842 to 0.864 and for male fish ranged from 0.848 to 0.874. The gonadosomatic index of female fish was highest in June (1.68%) and lowest in November (0.69%); that of male fish was highest in June (0.53%) and lowest in September (0.15%). The sexual maturity rate (SMR) of female fish peaked in May, with SMRs of 33.3% (stage III) and 58.3% (stage IV). In conclusion, C. lucius has a positive allometric range (b > 3), reaching sexual maturity when its length reaches 21.39 cm for both sexes, and the spawning season begins in December but peaks in May and June. [ABSTRACT FROM AUTHOR]

Abnormal sexual maturity exhibits significant detrimental effects on adult health outcomes, and previous studies have indicated that targeting histone acetylation might serve as a potential therapeutic approach to regulate sexual maturity. However, the mechanisms that account for it remain to be further elucidated. Using the mouse model, we showed that Trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, downregulated the protein level of Hdac1 in ovaries to promote the apoptosis of granulosa cells (GCs), and thus arrested follicular development and delayed sexual maturity. Using porcine GCs as a cell model, a novel sexual maturity-associated lncRNA, which was named as the stimulatory factor of follicular development (SFFD), transcribed from mitochondrion and mediated by HDAC1, was identified using RNA sequencing. Mechanistically, HDAC1 knockdown significantly reduced the H3K27ac level at the −953/−661 region of SFFD to epigenetically inhibit its transcription. SFFD knockdown released miR-202-3p to reduce the expression of cyclooxygenase 1 (COX1), an essential rate-limited enzyme involved in prostaglandin synthesis. This reduction inhibited the proliferation and secretion of 17β-estradiol (E2) while promoting the apoptosis of GCs. Consequently, follicular development was arrested and sexual maturity was delayed. Taken together, HDAC1 knockdown-mediated SFFD downregulation promoted the apoptosis of GCs through the miR-202-3p-COX1 axis and lead to delayed sexual maturity. Our findings reveal a novel regulatory network modulated by HDAC1, and HDAC1-mediated SFFD may be a promising new therapeutic target to treat delayed sexual maturity. [ABSTRACT FROM AUTHOR]

Samples caught by beach seine nets in the fishing season of 2019-2021 in the southern costal zones of the Caspian Sea were used to study reproductive biology of Cyprinus carpio. Totally, 435 sea carp, including 237 female and 198 male were sampled, and their age and maturity stages were determined over sampling period. The results indicated that age range of the sampled C. carpio varied from 1 to 6 years in males, from 1 to 9 years in females, and from 1 to 9 years in combined sexes. The highest frequency of samples was in the age group of 1 for males (54.4%), 2 for females (34%), and 4 years for combined sexes (26.6%). Frequency of fish observed in the V and VI maturity stages was 45.14% and 27.17%, respectively. According to the frequency of different maturity stages and also the trend of changes in Gonado-somatic index (GSI), two spawning peaks were observed in C. carpio, including weak peak occurred in December-January and strong peak observed in March-April. The female mean length at sexual maturity (Lm50%) was 27.7 cm. Absolute and relative fecundity (mean ± SD) of C. carpio were 429310±233479 and 668±319 eggs, respectively. Since, there was an overlap between the spawning peak of C. carpio and beach seine fishing period for bony fish, it is proposed that fishing season to be banned at the beginning of April. [ABSTRACT FROM AUTHOR]

The alien Red Sea goatfish (Parupeneus forsskali) was recently reported in the Mediterranean Sea, as a species that migrated two decades ago through the Suez Canal. In this work, efforts are being made to fill knowledge gaps on its biology, through information based on 131 Red Sea goatfish specimens collected from commercial fishing vessels in the south-eastern coasts of the Aegean Sea, Greece (Eastern Mediterranean). The largest specimen examined measured 26 cm in total length (Lmax), while otolith annual ring determination showed that the maximum recorded age was 4 years. The Von Bertalanffy growth function parameters were estimated as follows: L∞ = 32.44 cm, Κ = 0.31 y−1 and t0= −0.08 y. The diet of the specimens was dominated by Decapoda and Amphipoda (IRI = 66%) with an estimated trophic level of 3.58 (±0.53), characterizing the species as carnivorous with preference for Crustacea prey. Length (Lm) and age (tm) at maturity were estimated to be 19.6 cm and 2.8 years, respectively. The species exhibited larger reproductive load (Lm/Lmax) in the non-native regions compared with its native distribution in the non-native regions compared with its native distribution. In conclusion, further research is required in order to elucidate differences of the species' life-history traits between its native and non-native distribution. [ABSTRACT FROM AUTHOR]

ABSTRACT: At the onset of sexual maturity, the increasing circulating estrogen stimulates the formation of medullary bone, which provides available calcium for eggshell formation. The bone loss of laying hens is caused by the continuous dynamic changes of structure bone leading to bone fragility and susceptibility. The degree of medullary bone mineralization in sexual maturity is positively correlated with bone quality in the late laying stage. This study aimed to explore the molecular regulation mechanism of bone metabolism pre- and postsexual maturity in hens based on the joint analysis of transcriptome and metabolome. A total of 50 Hy-line Sonia pullets with comparable body weight at 13 wk were selected. Eight pullets were killed at 15 wk (juvenile hens, JH) and 19 wk (laying hens, LH), and LHs were killed within 3 h after oviposition. Differentially expressed genes and metabolites in tibia were analyzed based on transcriptome and metabolome, and then combined to construct the relevant metabolisms and hub genes. In the LH hens, plasma levels of estrogen and tartrate-resistant acid phosphatase were significantly elevated by 1.7 and 1.3 times. In addition, the midpoint diameter, bone mineral density and bone mineral content of the tibia and femur were higher at 19 wk of age. A total of 580 differentially expressed genes were found between the JH and LH group in the tibia, including 280 up-regulated, and 300 down-regulated genes in the LH group. Gene set enrichment analysis (GSEA) showed that the intracellular biosynthesis and secretion of matrix vesicles were significantly enrichment in the LH hens. A total of 21 differential metabolites were identified between JH and LH group. Estradiol valerate positively correlated with L-theanine, tryptophan betaine, dopamine, and perindopril. Joint analysis showed that the top 20 hub genes were enriched in cholesterol biosynthesis and phospholipid metabolism, which played a key regulatory role in bone metabolism during pre- and postsexual maturity. These results provide a theoretical foundation for maintaining efficient egg production and reducing bone health problems in laying hens.

ABSTRACT: The photoperiod is an important factor during rearing and laying period that affects age and body weight at sexual maturation and reproductive performance in poultry; however relevant research on this factor in pigeons is still lacking. Thus, this study investigated the effects of different photoperiodic programs on the reproductive performance and hormonal profile in White King pigeons. From 101 d of age, the pigeons in the control group were exposed to a natural photoperiod until 160 d, and then to a photoperiod of 16 h (16 light [L]: 8 dark [D]) and lasted for 200 d. Pigeons in the 3 experimental groups were exposed to a short photoperiod of 8L: 16D until 160 d, and then to 14L: 10D, 16L: 8D, and 18L: 6D, respectively. The results showed that light-restriction (8L: 16D) during the rearing period and then 14L: 10D or 16L: 8D photostimulation delayed the age at first egg laying in pigeons. However, 16L: 8D after an 8L: 16D photoperiod during the breeding period ensured maximum photosensitivity, and significantly improved the reproductive performance (egg production and fertility rates) in pigeons. Moreover, the highest reproductive performance in group under16L: 8D after 8L: 16D photoperiodic program was accompanied by improved follicle-stimulating hormone and estradiol levels and reduced prolactin hormone levels. The results indicated that photoperiodic programs from rearing to laying period are closely related to the reproductive performance of White King pigeons. The results provide information that 8L: 16D during rearing period and 16L: 8D during laying period can be used to enhance reproductive performance in the pigeon industry.

Abstract Background Paphia undulata, The Short-Necked Clam, is an edible marine bivalve that is consumed internationally and locally in Egypt. Overfishing and pollution have caused population declines in Egyptian fisheries during the last decade. Accurate reproductive biology knowledge is critical for designing long-term exploitation strategy for this resource. P. undulata spawning and gametogenic cycle research were carried out from January to December 2020 along Timsah Lake, Suez Canal, Egypt. Results These clams are functionally dioecious with a very low incidence of hermaphroditism. The sex ratio of the clam population was 1.0:1.07:0.04 for male, female and hermaphrodite respectively. The shell lengths of the collected clams were 4.64 ± 0.83 cm in males, 4.55 ± 0.9 cm in females and 4.19 ± 0.3 cm in hermaphrodite clams. The sizes at the onset of sexual maturity in both males and females were 2.1 cm and 2.5 cm respectively. Conclusions Reproductive studies revealed that this species has a prolonged spawning season that is not restricted to a specific period.

The near-threatened Ailia coila, commonly referred to as Gangetic ailia, is a catfish species in the Ailiidae family that is indigenous to Bangladesh, Pakistan, Nepal, and India. This study describes the comprehensive explanation of life-history traits of Ailia coila, including length-frequency distribution (LFD), growth pattern (length-weight relationships, LWRs and length-length relationship, LLR), form factor (a3.0), condition factors (allometric, KA; Fulton’s, KF; relative, KR and relative weight, WR), size at first sexual maturity (Lm), optimum catchable length (Lopt) and natural mortality (Mw) from the Tetulia River in southern Bangladesh. Additionally, Lα, a3.0, Lm, Mw and Lopt from various water bodies worldwide using the existing literature were calculated in this study. A total of 316 samples were randomly collected occasionally using traditional gear for a year from July 2021 to June 2022. With an accuracy of 0.01 cm and 0.01 g, each fish’s total length (TL), standard length (SL), and body weight (BW) were measured. The group from 10.00 to 10.99 cm TL was numerically leading and the b values of LWRs indicate positive allometric growth. The a3.0 was 0.005 and KF was the best for assessing the well-being of A. coila. Additionally, WR indicates that the habitat was imbalanced with higher predators. The calculated Lm, Lopt and Mw were 9.19 (~ 9.2 cm TL), 10.7 cm TL and 1.37 year−1 for A. coila in the Tetulia River, respectively. These insights are vital for future research and recommending suitable management strategies for A. coila in the Tetulia River and neighboring basins.

Understanding the reproductive characteristics of a species is of crucial for accurate stock assessment and management plans to ensure sustainable fisheries. In this study, the size at 50% sexual maturity (L50) parameters in different bio-ecological provinces were estimated for bigeye tuna, Thunnus obesus, sampled from the Eastern Pacific Ocean tuna fisheries-dependent survey from 2013 to 2019. The overall sex ratio of the catch during the sampling differed significantly from 1:1. Bigeye tuna exhibit sexual dimorphism in the growth of males and females, with a clear shift in predominance from female to male with increasing sizes. In the North Pacific Sub-tropical Gyre (east) (NPST-east), North Pacific Tropical Gyre (NPTG), Pacific North Equatorial Countercurrent (PNEC), and Pacific Equatorial Divergence (PEQD), females (meals) reached sexual maturity round 102 cm (106 cm), 106 cm (100 cm), 125 cm (110 cm), and 113 cm (110 cm), respectively, the estimated L50 of bigeye tuna was 124.08 cm, 121.97 cm, 139.92 cm and 132.45 cm, respectively. The degree of populations mixing between equatorial (PNEC and PEQD) and high-latitude regions (NPST-east and NPTG) is extremely small, but it is reasonably high between the NPST-east and NPTG or PNEC and PEQD. These parameters were significantly different, suggesting the occurrence of a spatial difference in the size-at-maturity of bigeye tuna between these bio-ecological provinces. The findings of this study provide the key information for understanding the life history of bigeye tuna in the Eastern Pacific Ocean and will contribute to the conservation and sustainable yield of this species.

Abstract Rhesus macaques (Macaca mulatta, RMs) are widely used in sexual maturation studies due to their high genetic and physiological similarity to humans. However, judging sexual maturity in captive RMs based on blood physiological indicators, female menstruation, and male ejaculation behavior can be inaccurate. Here, we explored changes in RMs before and after sexual maturation based on multi-omics analysis and identified markers for determining sexual maturity. We found that differentially expressed microbiota, metabolites, and genes before and after sexual maturation showed many potential correlations. Specifically, genes involved in spermatogenesis (TSSK2, HSP90AA1, SOX5, SPAG16, and SPATC1) were up-regulated in male macaques, and significant changes in gene (CD36), metabolites (cholesterol, 7-ketolithocholic acid, and 12-ketolithocholic acid), and microbiota (Lactobacillus) related to cholesterol metabolism were also found, suggesting the sexually mature males have stronger sperm fertility and cholesterol metabolism compared to sexually immature males. In female macaques, most differences before and after sexual maturity were related to tryptophan metabolism, including changes in IDO1, IDO2, IFNGR2, IL1Β, IL10, L-tryptophan, kynurenic acid (KA), indole-3-acetic acid (IAA), indoleacetaldehyde, and Bifidobacteria, indicating that sexually mature females exhibit stronger neuromodulation and intestinal immunity than sexually immature females. Cholesterol metabolism-related changes (CD36, 7-ketolithocholic acid, 12-ketolithocholic acid) were also observed in female and male macaques. Exploring differences before and after sexual maturation through multi-omics, we identified potential biomarkers of sexual maturity in RMs, including Lactobacillus (for males) and Bifidobacterium (for females) valuable for RM breeding and sexual maturation research.

Abstract Age at sexual maturity is a key life history trait that can be used to predict population growth rates and develop life history models. In many wild animal species, the age at sexual maturity is not accurately quantified. This results in a reduced ability to accurately model demography of wild populations. Recent studies have indicated the potential for CpG density within gene promoters to be predictive of other life history traits, specifically maximum lifespan. Here, we have developed a machine learning model using gene promoter CpG density to predict the mean age at sexual maturity in mammalian species. In total, 91 genomes were used to identify 101 unique gene promoters predictive of age at sexual maturity across males and females. We found these gene promoters to be most predictive of age at sexual maturity in females (R2 = 0.881) compared to males (R2 = 0.758). The median absolute error rate was also found to be lower in females (0.427 years) compared to males (0.785 years). This model provides a novel method for species‐level age at sexual maturity prediction without the need for long‐term monitoring. This study also highlights a potential epigenetic mechanism for the onset of sexual maturity, indicating the possibility of using epigenetic biomarkers for this important life history trait.

ABSTRACT: Sexual maturity is a crucial factor in the formation and development of poultry reproductive capacity. The nutritional status has been confirmed to play an important role in the regulation of sexual maturity. To investigate the effect of dietary energy levels on sexual maturity in chicken, diets with 3 energy levels (group L: 2,573 kcal/kg, group C: 2,836 kcal/kg, group H: 3,122 kcal/kg) were implemented to feed Guangyuan Gray chickens. During this trial, body weight, body size, organ development, sexual maturity, reproductive performance and blood biochemical parameters were monitored. The earlier sexual maturity was observed in group H, as well as a heavier first egg weight, larger interpubic distance and higher total cholesterol (T-CHO) content at sexual maturity. The dietary energy levels had no significant effect on body weight at first egg and egg production at 300 d of age. Although dietary energy levels had a significant effect on body weight, comb length, tibia length and girth, abdominal fat weight, oviduct weight and length, T-CHO, triglyceride (TG) content and estradiol (E2) level during the rearing period. No significant difference of gonadotropin releasing hormone (GnRH) and luteinizing hormone (LH) level among 3 groups was observed during the trial. The dietary energy levels had effects on mRNA expression of GnRH, estrogen receptor 1 (ESR1), estrogen receptor 2 (ESR2) in hypothalamus, gonadotropin inhibitory hormone receptor (GnIHR) in pituitary and luteinizing hormone receptor (LHR), ESR2 in ovary. The GnIHR/GnRHR ratio in pituitary was higher before sexual maturity and decreased at sexual maturity. The results of correlations analysis found that all the body size, carcass traits, serum biochemical parameters negatively correlated with age at first egg except for interpubic distance and serum blood glucose content. Collectively, dietary energy levels had effects on sexual maturity of chicken, which may be achieved by affecting body weight, gonad development, endocrine and the mRNA expression of genes related to hypothalamus-pituitary-gonad axis. These results further set our understanding of how dietary energy regulates sexual maturity.

Objective: Scads Decapterus spp. occur widely throughout tropical, subtropical, and temperate oceans and are both economically and ecologically important species. They are among the main commercial fish species caught by the light falling‐net fishery in the South China Sea, which is dominated by Mackerel Scad Decapterus macarellus and Shortfin Scad D. macrosoma. Stock assessment is an approach used to guide effective management and maintain fishery sustainability. Methods: Two data‐poor methods, namely length‐based Bayesian biomass estimation and length‐based spawning potential ratio, were applied to assess the status of Mackerel Scad, the most dominant Decapterus species in the South China Sea. Electronic length–frequency analysis was used to estimate von Bertalanffy growth parameters (asymptotic length Linf and growth coefficient K) to serve as priors. Result: The results show the estimated Linf and K of Mackerel Scad in the South China Sea as 36.0 cm and 0.37/year, respectively. Estimated natural mortality was 0.74/year, and mean fork length at 50% sexual maturity was 24.29 cm. Length‐based Bayesian biomass estimation analysis showed that the estimated relative stock size had decreased from 1.3 in 2012–2014 to 0.7 in 2019–2021, indicating an overfished status. Length‐based spawning potential ratio analysis showed that the estimated spawning potential ratio for this fishery decreased from 13% to 12%, which is significantly below the limit reference point of 20%. Conclusion: Our results obtained through length‐based methods indicate the lower SPR of Mackerel Scad stock was due to catching an excess of juveniles. Therefore, we highlight the need to increase the minimum mesh size in the fishing nets and strengthen international cooperation for conserving this shared stock in the South China Sea. Impact statementThe current fishing problem facing Mackerel Scad in the South China Sea is catching an excess of juveniles. A fork length of 24.29 cm was recommended as the minimum fishing size. Our study contributes to guiding effective management and maintaining this fishery's sustainability. [ABSTRACT FROM AUTHOR]

Background: Paphia undulata, The Short-Necked Clam, is an edible marine bivalve that is consumed internationally and locally in Egypt. Overfishing and pollution have caused population declines in Egyptian fisheries during the last decade. Accurate reproductive biology knowledge is critical for designing long-term exploitation strategy for this resource. P. undulata spawning and gametogenic cycle research were carried out from January to December 2020 along Timsah Lake, Suez Canal, Egypt. Results: These clams are functionally dioecious with a very low incidence of hermaphroditism. The sex ratio of the clam population was 1.0:1.07:0.04 for male, female and hermaphrodite respectively. The shell lengths of the collected clams were 4.64 ± 0.83 cm in males, 4.55 ± 0.9 cm in females and 4.19 ± 0.3 cm in hermaphrodite clams. The sizes at the onset of sexual maturity in both males and females were 2.1 cm and 2.5 cm respectively. Conclusions: Reproductive studies revealed that this species has a prolonged spawning season that is not restricted to a specific period. [ABSTRACT FROM AUTHOR]

A population of the porcelain crab Pachycheles laevidactylus was evaluated based on sex ratio, sexual dimorphism, reproductive intensity, relative growth and sexual maturity. The porcelain crabs were identified, sexed and measured as follows: carapace (CL, length; CW, width), chelar propodus (PL, length; PH, height) and abdomen (AL, length; AW2 and AW5, the width of the 2nd and 5th abdominal somite, respectively). For the 1,109 specimens analyzed, the sex ratio was 1:1, but contrasted in some seasons. Females were significantly larger than males, and ovigerous females were recorded in all seasons, with greater intensity in autumn and winter. In males, the biometric ratios of the major chelar propodus (PHxCL and PLxCL) showed positive allometry regarding body size, with a reduction in the allometry rate after puberty. The same occurred with females for the biometric ratios of the abdomen (AW2xCL and AW5xCL). Males attain morphological sexual maturity at 3.48 mm CL, earlier than females, which occurred at 5.00 mm CL. In this study, P. laevidactylus matured with a larger size than reported for others analyzed in the temperate zone. It is the first study addressing aspects of the population biology of P. laevidactylus in a region with a subtropical climate. [ABSTRACT FROM AUTHOR]

The Mediterranean Sea is one of the busiest areas worldwide in terms of maritime activity and faces considerable anthropogenic disturbances, such as pollution by hydrocarbons and heavy metals. This study evaluated the environmental status of three sites on the Algerian coast using the annelid polychaete Perinereis cultrifera as a biomonitoring sentinel species. It included different reproductive parameters such as oocyte diameter, frequency distributions, sexual maturity index, biochemical quantitative parameters represented by the vitellogenins and vitellins, and a histological study of the coelome during the reproductive period. The results showed that the females collected from El-Kala (healthy site) have the highest diameter 304.1 ± 24.3 μm during April but the values were increased in Annaba 290.0 ± 21.0 μm and Skikda 245.3 ± 26.7 μm. Significant differences were observed between worms from the three study sites during the three months of the study. Moreover, the size-frequency indicated that a relatively high proportion of females containing mature oocytes was found in April in females collected at El-Kala 52.4%, 46.4% in females collected at Annaba and 36.7% in females collected at Skikda. In addition, regarding the sexual maturity index, the highest values were recorded in April (3.8, 2.9, and 1.9) at the El-Kala, Annaba, and Skikda study sites. However, the biochemical analysis demontrated that the highest mean concentration of vitellogenin was in females of El-Kala (5.3 ± 0.3 µg/mg of coelomic fluid) in April, and the lowest mean concentration was measured in females of Skikda (1.5 ± 0.2 µg/mg of coelomic fluid). Therefore, the highest mean concentration of vitellin was measured in females of El-Kala (4.4 ± 0.2 µg/mg of oocytes) in April, while the lowest mean concentration of vitellin was measured in females of Skikda (1.02 ± 0.2 µg/mg of oocytes) in May. Significant differences were observed between worms from the three sites during the three months of the study. Furthermore, histological observations revealed that oogenesis was asynchronous, with oocytes at different stages of vitellogenesis simultaneously present. The structure of the oocytes of females collected at El-Kala showed intense vitellogenic activity due to the presence of very dense yolk cells. In contrast, the oocytes of the females collected from the two polluted sites (Annaba and Skikda) were small, vitellogenesis presented low intensity, and yolk cells were less frequent at the periphery and less uniform at the cytoplasmic mass; the nucleus was smaller, indicating a slower vitellogenic activity. These observations confirm the previously obtained results.

The objective of this study was to determine if sire or dam had a stronger impact on age at first parturition of Brahman heifers (n = 833) born between 2000- 2021. Typically, in Bos taurus heifers, puberty occurs between 10 to 12 mo of age leading to parturition of the first calf occurring around 24 mo of age. However, in Bos indicus cattle, puberty is achieved between 15 to 17 mo of age leading to a first calf around 36 mo of age. The ability of heifers to achieve pubertal status earlier plays a vital role in reproductive success. For selection purposes, knowing if early pubertal attainment is influenced more by the sire or dam is important for herd management. For this study, to minimize any epigenetic and environmental changes, all heifers originated and were developed at the Texas A&M AgriLife Research Center at Overton. Sire groups (SG) and dam groups (DG) were established based on the number of offspring used in the study. Sire groups were comprised of SG-1 (1+ calves sired; n = 58 sires), SG-2 (5+ calves sired; n = 44 sires), SG-3 (10+ calves sired; n = 31 sires), SG-4 (15+ calves sired; n = 23 sires), SG-5 (20+ calves sired; n = 17 sires), and SG-6 (25+ calves sired; n = 12 sires). Dam groups consisted of DG-1 (1+ calves; n = 489 dams), DG-2 (2+ calves; n = 215 dams), DG-3 (3+ calves; n = 81 dams), DG-4 (4+ calves; n = 38 dams), and DG-5 (5+ calves; n = 9 dams). Statistical analysis (PROC GLM; SAS 9.4) included the fixed effect of sire group (dam group) and all dams (sires) utilized in that grouping. Significance for age at first calving was considered at P < 0.05. Mean separation for age was performed using LSmeans. Sire significantly impacted age at first calving in SG-1 (P = 0.0173) vs dam effect (P = 0.3993; n = 489 dams), SG-2 (P = 0.0159) vs dam effect (P = 0.5476; n = 481 dams), SG-3 (P = 0.0023) vs dam effect (P = 0.2532; n = 439 dams), SG-4 (P = 0.0022) vs dam effect (P = 0.3997; n = 400 dams), SG-5 (P = 0.0002) vs dam effect (P = 0.0602; n = 361 dams), and SG-6 (P = 0.0005) vs dam effect (P = 0.1058; n = 305 dams). The dam impact on age at first calving was never significant in the dam groupings but sires did impact age at first calving in two groups: DG-1 (P = 0.3993) vs sire effect (P = 0.0173; n = 58 sires), DG-2 (P = 0.4823) vs sire effect (P = 0.0173; n = 56 sires), DG-3 (P = 0.3011) vs sire effect (P = 0.3420; n = 49 sires), DG-4 (P = 0.3911) vs sire effect (P = 0.6278; n = 40 sires), and DG-5 (P = 0.3042) vs sire effect (P = 0.9159; n = 23 sires). In summary, evaluation of sire and dam influences on age at first parturition for female offspring demonstrates that the ability to calve at an earlier age is influenced by the sire but not the dam. Further studies into the mechanisms for the transmission of this trait are warranted. [ABSTRACT FROM AUTHOR]

The mammalian pituitary gland drives highly conserved physiological processes such as somatic cell growth, pubertal transformation, fertility, and metabolism by secreting a variety of hormones. Recently, single-cell transcriptomics techniques have been used in pituitary gland research. However, more studies have focused on adult pituitary gland tissues from different species or different sexes, and no research has yet resolved cellular differences in pituitary gland tissue before and after sexual maturation. Here, we identified a total of 15 cell clusters and constructed single-cell transcriptional profiles of rats before and after sexual maturation. Furthermore, focusing on the gonadotrope cluster, 106 genes were found to be differentially expressed before and after sexual maturation. It was verified that Spp1, which is specifically expressed in gonadotrope cells, could serve as a novel marker for this cell cluster and has a promotional effect on the synthesis and secretion of follicle-stimulating hormone. The results provide a new resource for further resolving the regulatory mechanism of pituitary gland development and pituitary hormone synthesis and secretion.

ABSTRACT: The aim of this study was to assess the effects of energy-restricted feeding during growing phase on the productive performance of Hyline Brown laying hens aged 6 to 72 wk. A total of 720 six-week-old layer chicks were allocated equally to 3 groups with 6 replicates of 40 pullets each, and were fed 1 of 3 diets that were nutritionally similar except for the apparent metabolizable energy corrected for nitrogen (AMEn) content. At the age of 6 to 17 wk, the pullets in the control group were given diet with 2,850 kcal/kg AMEn, and were fed ad libitum. The levels of AMEn in diet of pullets in the experimental groups were 90% (2,565 [2,850 × 90%] kcal/kg) and 80% (2,280 [2,850 × 80%] kcal/kg) of that in control group, and the daily amount of feed was restricted to the absolute quantity of the diet consumed by pullets in control group. At the age of 18 to 72 wk, all the hens were fed with the same diets ad libitum. As energy restriction increased in the growing phase, body weight (BW) dropped at the ages of 12 and 15 to 23 wk (at 23 wk: P = 0.001; at other ages: P < 0.001), but it showed no significant difference at 24 wk (P = 0.071). At 20 wk, restricting energy induced a delay in the development of sexual organs, including the ovary stroma, oviduct, and small yellow follicle (P < 0.05), as well as a delay in sexual maturity (P < 0.05). Consequently, the laying rate in the first and second periods dropped linearly (P = 0.046, 0.030, and 0.038, P < 0.001, respectively). The coefficient of variation (CV) in the BW at 19, 20, and 21 wk (P = 0.040, 0.023, and 0.042, respectively), the CV of age at first egg (P < 0.001), and CV of individual egg number at age 18 to 72 wk (P < 0.001) decreased linearly. There was a linear increase in the laying rate of hens in the later periods (at age 32–72 wk, P < 0.05), as well as in the average total egg number per hen and average laying rate at the age of 18 to 72 wk (P = 0.006). The average egg mass also showed a linear increase with increasing levels of energy restriction (P < 0.001). In summary, although appropriate energy restriction during growing phase delayed sexual maturity and sexual organ development in early-laying Hyline Brown pullets, it improved uniformity of BW, age at first egg laying, and individual egg number, and increased egg number per hen, laying rate, average egg mass, and number of settable eggs from 18 to 72 wk of age.

The present study examined body length (precaudal length, PCL) and age at sexual maturity, as well as fecundity and maternal investment in the Pacific spiny dogfish Squalus suckleyi, a long‐term commercially exploited shark in the western North Pacific, using samples caught in several fisheries and across seasons. The PCL and age at 50% sexual maturity of males were 60.6 cm and 9.4 years, respectively, and those of females were 73.1 cm and 17.8 years, respectively. The PCL and age at 50% maternity were 77.4 cm and 19.7 years, respectively. General or generalized linear models revealed that capture by different fishing method did not significantly correlate with sexual maturity and maternity rates or litter size. Other general linear models revealed an increase in offspring size with maternal size, but litter size was not affected by embryonic development. These findings indicate that the reproductive potential of Pacific spiny dogfish is relatively high throughout the whole North Pacific region because of a smaller size and earlier age at sexual maturation in both sexes. In addition, pregnant females displayed no resting phase and produced 0.45 more embryos per centimetre of PCL in their lifetime after the onset of maturity, which is higher than in the eastern North Pacific. We suggest that these qualities are not a consequence of stock decline associated with the long‐term exploitation of the species, but that its high reproductive potential has likely contributed to the long‐term stability of the landings in Japan. Significance statement: While reproductive potential has been determined for many fish species, such information is scarce for Pacific spiny dogfish. We evaluated the reproductive characteristics of this species in the major fishing grounds of the western North Pacific. The productivity and rebound potential of sharks is extremely low compared with those of bony fishes. However, our results indicate that even if the reproductive potential has a small effect on the population dynamics, it should not be ignored for sustainable stock utilisation. [ABSTRACT FROM AUTHOR]

The ability to visualise the internal anatomical structures of fish provides important information on their reproductive status and body condition and has made important contributions to many areas of fish biology. Obtaining information on the internal anatomy of fish has traditionally required euthanasia and dissection. Although ultrasonography is now increasingly used to study internal fish anatomy without the need for euthanasia, traditional techniques still require restraint and contact with the animal, both of which are known to cause stress. This has prompted the development of waterproof, contactless and portable equipment to allow ultrasonographic examinations to be carried out in free‐swimming individuals, which also facilitates the application of this tool in wild populations of endangered species. This study reports the validation of this equipment using anatomical examinations of nine manta and devil ray (Mobulidae) specimens landed at fish markets in Sri Lanka. The species studied were Mobula kuhlii (n = 3), Mobula thurstoni (n = 1), Mobula mobular (n = 1), Mobula tarapacana (n = 1) and Mobula birostris (n = 3). The use of this equipment was further validated with ultrasonographic examinations in 55 free‐swimming reef manta rays Mobula alfredi, which enabled maturity status to be quantified in 32 females. Structures successfully identified in free‐swimming individuals were the liver, spleen, gallbladder, gastrointestinal tract, skeletal structures, developing follicles and uterus. The study demonstrated that ultrasonography provided a reliable method of determining both sexual maturity and gestational status in free‐swimming M. alfredi. The methodology induced no detectable signs of disturbance to the animals involved and therefore offers a viable and practical alternative to invasive techniques currently used to study anatomical changes in both captive and wild marine organisms. [ABSTRACT FROM AUTHOR]

Simple Summary: Histology and stereology were used to estimate the sexual maturity phase for the European Plaice, as well as a description of the oogenesis cycle and size at first maturity. This study provides a method to accurately determine a key parameter for fisheries management that may be used for other species. The following paper gives a detailed description of the oogenesis cycle for the European Plaice (Pleuronectes platessa), from oogonia to post-ovulatory follicle, including ovarian follicle and zona pellucida sizes. Noteworthy particularities were the difficulty in identifying cortical alveoli due to their very small size. Quantitative histology (stereology) on histological slides was used to determine a first size at maturity for females from the English Channel, which was found to be smaller compared to the literature (19 cm). Stereology also determined a first spawning event starting in January, with a peak in February and ongoing until March. Moreover, the use of stereology showed misclassifications for individuals categorized into a maturity phase using a macroscopic visual method. Misclassifications were found with individuals that had spawned (D) but were put under the immature (A) phase, and individuals in development (B) classified under D. [ABSTRACT FROM AUTHOR]