Understanding crop colonization of oilseed rape crops by the cabbage stem flea beetle (Psylliodes chrysocephala L. (Coleoptera: Chrysomelidae))

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.

Research Note: Effect of different photoperiodic programs from rearing period on the reproductive performance and hormone secretion of White King pigeons

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.

Integrated transcriptomic and metabolomic analyses reveal potential regulatory pathways regulating bone metabolism pre- and postsexual maturity in hens

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.

Reproductive Seasonality, Estrous Cycle, Pregnancy, and the Recurrence of Postpartum Estrus Based on Long-Term Profiles of Fecal Sex Steroid Hormone Metabolites regarding Zoo-Housed Female Golden Takins (Budorcas taxicolor bedfordi)

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.

The Reproductive Biology of Puye (Galaxias maculatus) under Experimental Culture

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.

Determination of the growth performance and reproductive season of wild Channa lucius (Cuvier, 1831) populations of genus Channa (Channidae, Perciformes) in the Mekong Delta, Vietnam

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.

Physiological role of dietary energy in the sexual maturity: clues of body size, gonad development, and serum biochemical parameters of Chinese indigenous chicken

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.

HDAC1-Mediated lncRNA Stimulatory Factor of Follicular Development to Inhibit the Apoptosis of Granulosa Cells and Regulate Sexual Maturity through miR-202-3p-COX1 Axis

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.

Effects of energy restriction during growing phase on the productive performance of Hyline Brown laying hens aged 6 to 72 wk

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.

A Quantitative Histologic Analysis of Oogenesis in the Flatfish Species Pleuronectes platessa as a Tool for Fisheries Management

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.

Estimates of life history parameters in a high latitude, arid-country vervet monkey population

We present data on life history parameters from a long-term study of vervet monkeys in the Eastern Cape, South Africa. Estimates are presented of age at first conception for females and age at natal dispersal for males, along with the probability of survival to adulthood for infants born during the study, female reproductive life-span, reproductive output (including lifetime reproductive success for a subset of females), and inter-birth interval (IBI) duration. We also assess the effect of maternal age and infant survival on length of IBI. We then go on to compare life history parameters for our population with those from two East African populations in Kenya (Amboseli and Laikipia). We find there is broad consensus across the three populations, although mean infant survival was considerably lower for the two East African sites. Such comparisons must be made cautiously, however, as local ecology across the duration of the studies obviously has an impact on the estimates obtained. With this caveat in place, we consider that the concordance between values is sufficient to enable the values reported here to be used in comparative studies of primate life history, although data from habitats with higher rainfall and lower levels of seasonality are needed, and the results presented here should not be seen as canonical.

Use of underwater contactless ultrasonography to elucidate the internal anatomy and reproductive activity of manta and devil rays (Fam. Mobulidae)

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 about the internal anatomy of fish has traditionally required euthanasia and dissection. However, 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. Species studied were Mobula kuhlii (n = 3), M. thurstoni (n = 1), M. mobular (n = 1), M. tarapacana (n = 1) and M. 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. This article is protected by copyright. All rights reserved.

Integrated testis transcriptome and whole genome analysis of sexual maturity in Large White and Tongcheng pigs

Testicular development and spermatogenesis play critical roles in male fertility and sexual maturation. To explore the genetic basis and key genes related to the sexual maturity, we measured serum testosterone content and analyzed testis tissue sections of Large White (LW) and Tongcheng (TC) boars at an immature age. We then screened differentially expressed genes (DEGs) in testis development in both breeds using RNA-seq. Finally, we analyzed the selection signatures of both breeds to investigate which DEGs were subjected to positive selection. Oue findings showed that serum testosterone contents in TC pigs (~4 ng/mL) were much higher than those in LW pigs (< 0.95 ng/mL). Hematoxylin and eosin staining of testicular sections showed that the cross-sectional areas and perimeters of the seminiferous tubules in TC testes were larger and longer, than those in LW pigs. A total of 5,068 DEGs were selected by filtering criteria of q value < 0.05 and |log2(fold change)| ≥ 1. Gene Ontology analysis revealed that 250 genes were enriched in 11 biological process categories involved in sexual maturity. Most candidate genes, including TRIP13, NR6A1, STRA8, PCSK4, ACRBP, TSSK1B, and TSSK6, were under positive selection. These results provide a better understanding of the genetic basis for testicular maturation and are useful for enhancing boar reproductive traits through molecular breeding.

Gut microbiome and serum metabolome analyses identify biomarkers associated with sexual maturity in quails

Increasing evidence indicates that the gut microbiome plays an important role in host aging and sexual maturity. However, the gut microbial taxa associated with sexual maturity in quails are unknown. This study used shotgun metagenomic sequencing to identify bacterial taxa associated with sexual maturity in d 20 and d 70 quails. We found that 17 bacterial species and 67 metagenome-assembled genomes (e.g., Bacteroides spp. and Enterococcus spp.) significantly differed between the d 20 and d 70 groups, including 5 bacterial species (e.g., Enterococcus faecalis) enriched in the d 20 group and 12 bacterial species (e.g., Christensenella massiliensis, Clostridium sp. CAG:217, and Bacteroides neonati) which had high abundances in the d 70 group. The bacterial species enriched in d 20 or d 70 were key biomarkers distinguishing sexual maturity and significantly correlated with the shifts in the functional capacities of the gut microbiome. Untargeted serum metabolome analysis revealed that 5 metabolites (e.g., nicotinamide riboside) were enriched in the d 20 group, and 6 metabolites (e.g., D-ribose, stevioside, and barbituric acid) were enriched in the d 70 group. Furthermore, metabolites with high abundances in the d 20 group were significantly enriched for the KEGG pathways of arginine biosynthesis, nicotinate and nicotinamide metabolism, and lysine degradation. However, glutathione metabolism and valine, leucine and isoleucine biosynthesis were enriched in high-abundance metabolites from the d 70 group. These results provide important insights into the effects of gut microbiome and host metabolism on quail sexual maturity.

Transcriptomic analysis reveals the molecular mechanisms underlying osteoclast differentiation in the estrogen-deficient pullets

Several previous reports have suggested that estrogen (E2) is a vital signal responsible for the regulation of skeletal homeostasis and bone remodeling in mammals. E2 could efficiently accelerate the growth of medullary bone in pullets during sexual maturity. Furthermore, the low E2 level can strengthen the mechanical bone functions in female hens. However, mechanistic studies to describe the effects of E2 on bone in pullets during the initiation of the puberty period are remaining elusive. Therefore, the aim of this study was to explore the effect of inhibiting E2 biosynthesis on the biomechanical properties and its molecular mechanism during sexual maturity of pullets. In this study, a total of 90 Hy-line Sonia pullets with comparable body weight at 13 wk of age were selected and categorized into 2 separate groups. Daily, 0.5 mg/4 mL of letrozole (LZ) was orally administered to the treatment (TRT) group and 4 mL of saline to the control (CON) group of pullets for 6 wk. Compared with the CON group, a lower plasma E2 level was observed in the TRT group. Furthermore, plasma P, Gla protein (BGP), and 1,25-dihydroxy vitamin D3 (1,25-(OH)₂D₃) levels were markedly suppressed, whereas the plasma alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) levels were significantly elevated. Moreover, the cortical bone thickness and breaking strength of the tibia and femur, the bone mineral density of the humerus, and the bone mineral content of the humerus as well as the femur were increased significantly. The expression levels of 340 differentially expressed genes (DEGs) differed significantly between the CON and TRT group in the tibia at 19 wk of age. Among them, 32 genes were up-regulated, whereas 308 were down-regulated in the TRT group. The variations in candidate genes associated with osteoclast differentiation and cell adhesion may indicate that LZ inhibits E2 biosynthesis, consequently, reduces osteoclast differentiation by suppressing inter-cellular communication and cells attaching to extracellular matrix components. Taken together, the present study demonstrated that inhibiting E2 synthesis during sexual maturity of pullets decreased osteoclast differentiation and considerably enhanced bone quality.

Integrated Proteomic and Metabolomic Analyses of Chicken Ovary Revealed the Crucial Role of Lipoprotein Lipase on Lipid Metabolism and Steroidogenesis During Sexual Maturity

During sexual maturation and ovulatory cycle in chickens, ovaries undergo dynamic morphological and functional changes. The aim of this study was to evaluate the integrated proteome and metabolome analyses of chicken ovaries to characterize the changes in protein and metabolite profiles during sexual maturity. The ovary of Rohman layers before (125 days of age) and after (139 days of age) sexual maturation were collected for proteome and metabolome sequencing. The results showed that a total of 680 differentially expressed proteins (DEPs) and 1,046 differential metabolites (DMs) were identified in the chicken ovary during sexual maturity. Among the DEPs, 595 proteins were up-regulated and 85 were down-regulated, whereas 519 metabolites were up-regulated and 527 were down-regulated. KEGG pathway enrichment analysis showed that DEPs were significantly enriched in glycerolipid metabolism, calcium signaling pathway, folate biosynthesis, fat digestion and absorption, NF-kB signaling pathway, and PPAR signaling pathway. However, DMs were significantly enriched in the metabolism pathways, PPAR signalling pathway, glycerolipid metabolism, ferroptosis, biosynthesis of amino acids, and biosynthesis of unsaturated fatty acids. The results of the integrated analyses of DEPs and DMs revealed that the PPAR signaling pathway and glycerolipid metabolism were the most significantly enriched pathways. Among the identified DEPs, lipoprotein lipase (LPL) was upregulated in sexually mature chicken ovaries and was significantly enriched in the glycerolipid metabolism pathway, which may partially explain the possible reasons for steroidogenesis and lipid reserves responsible for oocyte maturation and ovarian follicle development during sexual maturity in chickens. The results further revealed that LPL silencing decreased the content of lipid droplets (LDs), as well as the mRNA expression of lipid metabolism-related genes including; sterol regulatory element binding protein-1 (SREBP-1) and fatty acid synthase (FASN); and steroidogenesis-related genes such as; cytochrome P450 11A1 (CYP11A1) and steroidogenic acute regulatory (StAR). The present study revealed that upregulation of LPL in the chicken ovary during sexual maturity promotes granulosa cell (GC) lipid metabolism and steroidogenesis. These findings provide a theoretical support for further studies to elucidate the mechanism of lipid metabolism to regulate the function of avian GCs during sexual maturity in chickens.

Age of sexual maturity and factors associated with neutering dogs in the UK and the Republic of Ireland

BACKGROUND

Surgical neutering of dogs is common, however the average age that dogs reach sexual maturity, are neutered, and dog owners' attitudes to neutering in the UK and the Republic of Ireland have not been explored in a longitudinal study.

METHODS

Owner-reported data on the timing of the first oestrus, timing of neutering and the reasons given for neutering dogs by 12 and 15 months of age were summarised. Factors associated with neutering at 15 months and factors associated with intention to neuter were quantified using multivariable logistic regression.

RESULTS

At 15 months of age, 90.0% (n = 207/230) of unneutered females had had their first oestrus. By 7, 9, 12 and 15 months of age, 22.1% (n = 131/593), 32.2% (197/593), 45.4% (n = 269/593) and 59.9% (n = 352/593) of dogs were neutered, respectively. Breed purity, dog's source, owners' intentions to neuter and the number of dogs in the household were associated with neuter status at age 15 months. Dog's sex, Kennel Club registration, dog's source, dogs intended to be working dogs and previous dog ownership were associated with intentions to neuter. Preventing puppies was the most common reason for neutering.

CONCLUSION

Understanding factors that shape owners' intentions to neuter can inform owner-vet discussions regarding whether to neuter a dog and the optimal age for doing so.

Complex axial growth patterns in an early Cambrian trilobite from South Australia

The exceptional fossil record of trilobites provides our best window on developmental processes in early euarthropods, but data on growth dynamics are limited. Here, we analyse post-embryonic axial growth in the Cambrian trilobite Estaingia bilobata from the Emu Bay Shale, South Australia. Using threshold models, we show that abrupt changes in growth trajectories of different body sections occurred in two phases, closely associated with the anamorphic/epimorphic and meraspid/holaspid transitions. These changes are similar to the progression to sexual maturity seen in certain extant euarthropods and suggest that the onset of maturity coincided with the commencement of the holaspid period. We also conduct hypothesis testing to reveal the likely controls of observed axial growth gradients and suggest that size may better explain growth patterns than moult stage. The two phases of allometric change in E. bilobata, as well as probable differing growth regulation in the earliest post-embryonic stages, suggest that observed body segmentation patterns in this trilobite were the result of a complex series of changing growth controls that characterized different ontogenetic intervals. This indicates that trilobite development is more complex than previously thought, even in early members of the clade.

Shedding light on the deep: The case of the velvet belly lanternshark in the North Aegean Sea

Main biological features were assessed for the first time in the deep-water shark Etmopterus spinax from Hellenic waters by examining 150 individuals caught incidentally in the bottom-trawl commercial fishery off Skyros island. Females outnumbered males and the overall sex ratio was 1.38:1. Females ranged from 122 to 311 mm in total length (L_T ) and males from 129 to 270 mm L_T , both exhibiting positive allometric growth. Total length-total mass relationships and frequency distributions did not show significant differences between females and males. Sexual dimorphism was not either found by analysing 56 different morphological characteristics. The effect of sex and season was more prominent on the gonadosomatic and hepatosomatic indices compared to the relative condition factor. Most of the individuals were sexually immature, with two specimens classified as mature, one gravid female reaching 311 mm L_T with undeveloped gonads and enlarged uteri with embryos, and one male reaching 270 mm L_T with enlarged gonads and rigid claspers with hooks. The present study highlights the importance of the sampling location as a breeding and nursery ground for E. spinax in the eastern Mediterranean Sea that should be taken into account for the species' conservation considering its intrinsic characteristics, which make it vulnerable to fishing pressure.

Morphometric description and biological notes on the rare kitefin shark Dalatias licha (Chondrichthyes: Dalatidae) from the Hellenic waters

Deep-sea sharks are among the less studied and most endangered elasmobranchs existing in the Mediterranean Sea, and therefore scientific research should be prioritized towards this vulnerable group of species. The aim of this study is to provide a morphometric description of the vulnerable kitefin shark by recording 55 standard morphometric measurements and to present its main biological features based on the examination of six historical specimens that were captured as by-catch by commercial bottom trawlers in the Hellenic waters.

Effect of age at first egg on reproduction performance and characterization of the hypothalamo-pituitary-gonadal axis in chickens

As an important indicator of sexual maturity of hens, age at first egg (AFE) is significantly associated with reproduction performance. In this study, 400 hens were divided into 6 groups based on AFE to analyze the difference of reproduction performance, reproduction hormone levels and the characterization of the hypothalamo-pituitary-gonadal axis in chickens. The results showed that the egg production of the hens in the late-maturing groups was significantly lower than that of the ones in other groups and the precocious hens had a lower egg production rate. The hens in late-maturing group had a lower fertility rate, LH levels and shorter duration of peak of egg production (PEP), the precocious hens had lower PRL levels. In addition, the characterization of the hypothalamo-pituitary-gonadal axis showed that the individuals with normal AFE had higher GNRH, GNRHR, ESR1, KITLG, and CYP11A1 expression levels than late-maturing and precocious individuals, which indicated that the chickens with normal AFE advantages on reproduction regulation system.

Expression Analysis of Circular RNAs in Young and Sexually Mature Boar Testes

Simple Summary

Circular RNAs are novel long non-coding RNA involved in the regulation of gene expression. Recently, the expression of circRNAs was characterized in testes of humans and bulls. However, the profiling of circRNAs and their potential biological functions in boar testicular development are yet to be known. In this study we characterized expression and biological roles of circRNAs in piglet (30 d) and adult (210 d) boar testes by high-throughput sequencing. We identified a large number of circRNAs during testicular development, of which 2326 circRNAs exhibited a significantly differential expression. Gene ontology analysis revealed that these differential expressed circRNAs might be involved in regulating spermatogenesis and hormone biosynthesis. Overall, the results indicate that circRNAs are abundantly expressed in boar testes and exhibit dynamic changes during testicular development. These findings will enable the provision of potential molecular markers for both breeding of elite boars and evaluating developmental status of boar testes.

Abstract

Testicular development is critical for male animals’ reproduction and is tightly regulated by epigenetic factors. Circular RNAs (circRNAs) were recently identified in the testes of humans and bulls. However, the expression profile of circRNAs and their potential biological functions in boar testicular development remain unclear. We identified 34,521 and 31,803 circRNAs in piglet (30 d) and adult (210 d) boar testes by high-throughput sequencing, respectively. Bioinformatics analysis revealed that these circRNAs are widely distributed on autosomes and sex chromosomes. Some of the host genes can generate multiple circRNAs. A total of 2326 differentially expressed circRNAs (DECs) derived from 1526 host genes was found in testicular development, of which 1003 circRNAs were up-regulated in adult boar testes and 1323 circRNAs were down-regulated. Furthermore, gene ontology analysis of host genes of DECs revealed that these circRNAs are mainly involved in regulating spermatogenesis, cilia motility, and hormone biosynthesis. The Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis revealed that the DECs are markedly enriched to stem cell pluripotency regulation, tight junctions, adhesion junctions, and cAMP signaling pathway. These results indicate that circRNAs are abundantly expressed in boar testes and exhibit dynamic changes during testicular development.

COMBINE: a coalesced mammal database of intrinsic and extrinsic traits

The use of species' traits in macroecological analyses has gained popularity in the last decade, becoming an important tool to understand global biodiversity patterns. Currently, trait data can be found across a wide variety of data sets included in websites, articles, and books, each one with its own taxonomic classification, set of traits, and data management methodology. Mammals, in particular, are among the most studied taxa, with large sources of trait information readily available. To facilitate the use of these data, we did an extensive review of published mammal trait data sources between 1999 and May 2020 and produced COMBINE: a COalesced Mammal dataBase of INtrinsic and Extrinsic traits. Our aim was to create a taxonomically integrated database of mammal traits that maximized trait number and coverage without compromising data quality. COMBINE contains information on 54 traits for 6,234 extant and recently extinct mammal species, including information on morphology, reproduction, diet, biogeography, life habit, phenology, behavior, home range, and density. Additionally, we calculated other relevant traits such as habitat and altitudinal breadths for all species and dispersal for terrestrial non-volant species. All data are compatible with the taxonomies of the IUCN Red List v. 2020-2 and PHYLACINE v. 1.2. Missing data were adequately flagged and imputed for non-biogeographical traits with 20% or more data available. We obtained full data sets for 21 traits such as female maturity, litter size, maximum longevity, trophic level, and dispersal, providing imputation performance statistics for all. This data set will be especially useful for those interested in including species' traits in large-scale ecological and conservation analyses. There are no copyright or proprietary restrictions; we request citation of this publication and all relevant underlying data sources (found in Data S1: trait_data_sources.csv), upon using these data.

Effects of energy-restricted feeding during rearing on sexual maturation and reproductive performance of Rugao layer breeders

The aim of this study was to assess the effects of energy-restricted feeding during rearing on the sexual maturation and reproductive performance of Rugao layer breeders. A total of 2,400 8-wk-old Rugao layer breeders were randomly assigned to one of 5 groups (480 pullets per group) with eight replicates and were fed one of 5 diets that were nutritionally similar with the exception of apparent metabolizable energy corrected for nitrogen (AME_n) content (2,850, 2,750, 2,650, 2,550, and 2,450 kcal AME_n/kg) from 8 to 18 wks of age. The daily amount of feed was restricted to the absolute quantity of the diet consumed by laying hens fed 2,850 kcal AME_n per kg diet ad libitum (control). From 18 to 52 wks of age, all hens were fed basal diets ad libitum. The body weight of layer breeders at 18 wks of age decreased linearly with increasing energy restriction (P < 0.001), but caught up within 3 wks of ad libitum feeding (P = 0.290). The coefficient of variation of the body weight of the hens at 18, 21, and 24 wks of age decreased linearly (P = 0.010, 0.025, and 0.041, respectively) with increasing energy restriction during rearing. Energy-restricted feeding delayed sexual organ development at 18, 20, and 22 wks of age, including the number of large yellow follicles, oviduct length, oviduct length index, oviduct index, and ovary stroma index (P < 0.05), and delayed sexual maturity, including the age at laying the first egg and the age at 5% and 50% egg production (P = 0.042, 0.004, and 0.029, respectively). Consequently, egg number from 5% to 50% egg production decreased linearly as the degree of energy restriction increased (P = 0.001) and egg production of hens in the energy-restricted feeding groups was lower than that of hens in the ad libitum feeding group (6.36, 6.43, 6.4, and 4.61% vs. 14.29%; P < 0.05) from 18 to 20 wks of age. Furthermore, egg weight increased linearly as energy restriction increased (P < 0.001) and laying hens in the most severe energy-restricted feeding group had more setting eggs (normal eggs weighing >40 g) than hens in the ad libitum feeding and lighter energy-restricted feeding groups (149.57 vs. 144.34, 142.66, 143.63, and 141.78; P < 0.05). No significant differences were observed in fertility, hatchability of fertile eggs, and hatchability of setting eggs (P = 0.381, 0.790, and 0.605, respectively). In conclusion, moderate energy restriction (85.97%, 2,450 vs. 2,850 kcal AME_n/kg) from 8 to 18 wks of age increased egg weight as well as the production of setting eggs in native layer breeders throughout the laying period, without adverse effects on productive performance from 18 to 52 wks of age, or fertility and hatchability at 52 wks of age.

Influence of Biological Maturity on the Muscular Strength of Young Male and Female Swimmers

The present study compared the evolution of strength and muscle mass in swimmers of both sexes across different chronological and biological ages. Seventy-six swimmers (55 males and 21 females) from 10 to 20 years of age underwent evaluations of sexual maturation using the developmental stage of the genitals (G1, G2, G3 G4 and G5) and pubic hair (P1, P2, P3, P4 and P5) (Tanner criteria), lean mass using the dual-energy X-ray absorptiometry method, and isokinetic strength of the knee extensor muscles. Boys did not present a significant difference in strength among G1, G2, and G3 (p > 0.05) nor between 10 and 13 years of age (p > 0.05), although significant differences in strength of the extensor (p = 0.038) muscles of the knee were found between G3 and G4 and between athletes of 10 and 14 years of age (extensor muscles, p = 0.033). Muscle mass was different between G3 and G4 (p = 0.003) and between 10 and 14 years of age (p = 0.020). The mean age of boys in the G4 pubertal stage was 13.7 ± 2.0 years, although from 12 to 16 years of age, boys are typically in the G4 stage. Girls showed no significant differences in strength nor muscle mass among the pubertal stages (p > 0.05). We conclude that by equating boys by chronological age, individuals with different pubertal development levels, muscle mass, and strength levels can be grouped. Therefore, the relationship between the level of pubertal deve-lopment and chronological age seems to be a useful strategy for grouping boys, while grouping girls by chronological age seems adequate for training and competition.

Impact of growth curve and dietary energy-to-protein ratio on productive performance of broiler breeders

The impact of growth curve (GC) and dietary energy-to-protein ratio on productive performance of broiler breeder females was investigated from 0 to 60 wk of age. One-day-old pullets (n = 1,536) were randomly allotted to 24 pens according to a 2 × 4 factorial arrangement, with 2 GC (standard growth curve = SGC or elevated growth curve = EGC, +15%) and 4 diets, differing in energy-to-protein ratio (96%, 100%, 104%, or 108% AME_n). Feed allocation per treatment was adapted weekly based on the desired GC, meaning that breeders fed the different diets within each GC were fed according to a paired-gain strategy. Linear and quadratic contrasts for energy-to-protein ratio for each GC were evaluated. Elevated growth curve breeders had an earlier sexual maturity (∆ = 4.1 d) than SGC breeders. Egg weight was higher for EGC breeders (∆ = 2.3 g) than for SGC breeders over the whole laying phase (22–60 wk). No differences between EGC and SGC breeders were observed on settable egg production. An increase in dietary energy-to-protein, at a similar BW, led to a linear increase in age at sexual maturity (β = 0.14 d/% AME_n). From 22 to 40 wk of age, an increase in dietary energy-to-protein ratio led to a linear decrease in egg weight (β = -0.06 g/% AME_n), regardless of GC. An interaction between GC and dietary energy-to-protein ratio was observed on settable egg production in this phase. An increase in dietary energy-to-protein ratio led to a linear decrease on settable egg production, which was more profound in EGC breeders (β = -0.70 eggs/% AME_n) than in SGC breeders (β = -0.19 eggs/% AME_n). From 41 to 60 wk of age, an interaction between GC and dietary energy-to-protein ratio was observed on egg weight. In the EGC, an increase in dietary energy-to-protein ratio led to a linear decrease in egg weight (β = -0.13 g/% AME_n), whereas in the SGC, a linear increase in egg weight was observed (β = 0.03 g/% AME_n). From 41 to 60 wk of age, no differences between diets were observed on settable egg production. It can be concluded that a higher GC of breeders has beneficial effects on egg weight, while maintaining settable egg production. Feeding breeders a lower dietary energy-to-protein ratio stimulated productive performance of broiler breeder hens, mainly during the first phase of lay. This effect was more profound when breeders were fed according to a higher GC.

Spermatogenic Activity and Sperm Traits in Post-Pubertal and Adult Tomcats (Felis catus): Implication of Intra-Male Variation in Sperm Size

Tomcats are considered to be adults at 1 year of age, although many reach sexual maturity at an earlier age. Nevertheless, we still know little about whether the spermatogenic activity and sperm quality of mature under one-year-old tomcats differ from those of tomcats that are over one-year-old. This study aims to evaluate the spermatogenic activity, sperm traits, and their relationships in mature tomcats at two different ages. Sixteen tomcats showing complete spermatogenesis and spermatozoa in their epididymal caudae were used and classified according to their age as post-pubertal (<1 year old) or adult (˃1 year old). Our results show that adult cats have higher epididymal sperm concentration and lower coefficient of variation in sperm head width and ellipticity than post-pubertal cats. However, they do not differ in their testicular and epididymal mass, spermatogenesis, and sperm traits such as motility, mitochondrial activity, morphology, morphometry, as well as plasma membrane, acrosome, and DNA integrity. Reduced intra-male variation of sperm head ellipticity is associated with higher testis mass, epididymis mass, and sperm concentration. Interestingly, low intra-male variation in sperm head size is associated with increased Sertoli cell function and reduced post-meiotic germ cell loss. These findings increase our knowledge about feline reproductive physiology and provide new insights into the functional significance of low intra-male variation in sperm size and shape in tomcats.

Scientific and Regulatory Policy Committee Best Practices: Documentation of Sexual Maturity by Microscopic Evaluation in Nonclinical Safety Studies

The sexual maturity status of animals in nonclinical safety studies can have a significant impact on the microscopic assessment of the reproductive system, the interpretation of potential test article-related findings, and ultimately the assessment of potential risk to humans. However, the assessment and documentation of sexual maturity for animals in nonclinical safety studies is not conducted in a consistent manner across the pharmaceutical and chemical industries. The Scientific and Regulatory Policy Committee of the Society of Toxicologic Pathology convened an international working group of pathologists and nonclinical safety scientists with expertise in the reproductive system, pathology nomenclature, and Standard for Exchange of Nonclinical Data requirements. This article describes the best practices for documentation of the light microscopic assessment of sexual maturity in males and females for both rodent and nonrodent nonclinical safety studies. In addition, a review of the microscopic features of the immature, peripubertal, and mature male and female reproductive system and general considerations for study types and reporting are provided to aid the study pathologist tasked with documentation of sexual maturity.

Experimental manipulation of body size alters life history in hydra

Body size has fundamental impacts on animal ecology and physiology but has been strongly influenced by recent climate change and human activities, such as size-selective harvesting. Understanding the ecological and life history consequences of body size has proved difficult due to the inseparability of direct effects of body size from processes connected to it (such as growth rate and individual condition). Here, we used the cnidarian Hydra oligactis to directly manipulate body size and understand its causal effects on reproduction and senescence. We found that experimentally reducing size delayed sexual development and lowered fecundity, while post-reproductive survival increased, implying that smaller individuals can physiologically detect their reduced size and adjust life history decisions to achieve higher survival. Our experiment suggests that ecological or human-induced changes in body size will have immediate effects on life history and population dynamics through a growth-independent link between body size, reproduction and senescence.

Effect of calfhood nutrition on metabolic hormones, gonadotropins, and estradiol concentrations and on reproductive organ development in beef heifer calves

This study examined the effect of plane of nutrition on the endocrinological regulation of the hypothalamic-pituitary-ovarian (HPO) axis in beef heifer calves during a critical sexual developmental window early in calf hood. Forty Holstein-Friesian × Angus heifers (mean age 19 d, SEM = 0.63) were assigned to a high (HI; ADG 1.2 kg) or moderate (MOD; ADG 0.50 kg) nutritional level from 3 to 21 wk of life. Intake was recorded using an electronic calf feeding system, BW was recorded weekly, and blood samples were collected on the week of age 5, 10, 15, and 20 for metabolite, reproductive, and metabolic hormone determination. At 19 wk of age, on sequential days, an 8-h window bleed was carried out for luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol analysis. To characterize anterior pituitary gland function, an intravenous GnRH challenge was conducted (19 wk of age). Blood was collected via a jugular catheter every 15 min for 135 min for the analysis of LH, FSH, and estradiol. Calves were subsequently euthanized at 21 wk of age; the anterior pituitary, metabolic organs, and reproductive tract were weighed, and ovarian surface follicular numbers and oocytes recovered were recorded. Mean ADG was 1.18 and 0.50 kg for HI and MOD, respectively, resulting in a 76.6-kg difference in BW (P < 0.001). Blood insulin, glucose, and IGF-1 concentrations were greater (P < 0.001) for HI compared with MOD. There was a diet × time interaction for leptin (P < 0.01); concentrations were greater in HI compared with MOD at 20 wk of age with no difference between treatments before this. Dietary treatment did not alter the concentrations of adiponectin or anti-mullerian hormone. There was a diet × time interaction for FSH, whereby MOD had greater concentrations than HI at 10, 15, and 20, but not at 5 wk of age. Over the duration of an 8-h window bleed (19 wk of age), serum concentrations of LH, LH pulse frequency, and LH pulse amplitude were unaffected by treatment, whereas FSH (0.23 vs. 0.43 ng/mL) and estradiol (0.53 vs. 0.38 ng/mL) concentrations were less than and greater, respectively, for HI than MOD (P < 0.05). Likewise, following a GnRH challenge, the area under the curve analysis revealed greater (P < 0.01) estradiol and lesser (P < 0.01) FSH concentrations in calves on the HI relative to MOD diet, whereas concentrations of LH were unaffected (P = 0.26) between treatments. Ovarian surface follicle numbers were greater (P < 0.05) in HI compared with MOD. Total reproductive tract, uterus, and ovarian tissue expressed relative to BW were greater (P < 0.05) for HI compared with MOD. In conclusion, enhanced nutrition in early calfhood advances the ontogeny development of the HPO axis.

Multiple-Phase Biometric Relationships and Sexual Maturity in the Atlantic Bluefin Tuna, Thunnus thynnus (Osteichthyes: Scombridae)

Most fish undergo distinct growth phases during ontogenesis. An extremely important passage from the juvenile to adult phase occurs at the onset of sexual maturity, which shows in body proportion and/or growth rate changes. These can be detected as change-points in biometric relationships. In this paper, the Atlantic bluefin tuna was analyzed to verify whether its somatic proportions show any sign of discontinuity during growth, i.e., whether any change-points may be detected in its somatic proportions. This fish has never been examined in this respect, and single-phase models, which are indeed easier to both compute and apply, are used in stock analyses. The following somatic relationships were analyzed in Atlantic bluefin tuna captured in the Mediterranean Sea between 1998 and 2010: "fork length-weight" regression, the von Bertalanffy growth equation, and "first dorsal spine cross section surface-fork length" regression. All of the examined relationships were found to be best modelled by multiple-phase regression equations, and all of them showed a change-point within the range of 101-110 cm fork length, which corresponds to 3-4 years of age. The present results, based on reproductive state-independent analyses, corroborate the disputed hypothesis that Atlantic bluefin tuna from the eastern stock in fact reproduce for the first time at this age.

Effects of age at photostimulation on sexual maturity and reproductive performance in rooster breeders

The 2 × 4 factorial experiment was designed to determine the effect of strain and photostimulation age on sexual maturity and reproductive performance of rooster breeders. A total of 96 White Leghorn (WL) and 120 Beijing You Chicken (BYC) roosters were randomly allocated to 4 treatments at 14 wk of age. The treatments represent photostimulation at 16, 18, 20, and 22 wk of age, respectively (PS16, PS18, PS20, and PS22), in both strains. Photostimulation was achieved by increasing the day length from 8L:16D to 14L:10D and by increasing lighting intensity from 10 lx to 80 lx. Three birds from each interaction were sacrificed to characterize the comb and testis weights at 4 time points: 1 d before photostimulation and 2, 4, and 6 wk after photostimulation. Semen quality and hatching performance with the semen of the experimental roosters were measured at 30 and 45 wk of age, respectively. Results showed that the testis weight of PS20 and PS22 in WL and BYC was 6.4- and 2.9-fold higher than that of PS18 before photostimulation, while testis weight of PS18 in both strains increased sharply after photostimulation. The diameter of seminiferous tubules increased in the photostimulated roosters as compared with the nonphotostimulated ones, and mature spermatozoa were produced 4 wk after photostimulation and at 20 wk of age for PS16. The WL had lower semen volume and total sperm count than BYC (P < 0.01), but there was no difference on effective sperm count (P > 0.05). In addition, semen quality traits were not affected by age at photostimulation (P > 0.05) in both strains. The fertility and hatching performance were not affected by strain or photostimulation age (P > 0.05). In summary, the sexual maturation of rooster breeders can be advanced by photostimulation at an early age, which does not lead to a difference in semen quality or hatching performance at adult stage.

Assessment of age-related morphological changes in the testes of post-hatch light ecotype Nigerian indigenous chicken

The age-related morphological changes of the testes in light ecotype Nigerian indigenous chicken were evaluated in this study using gross anatomical, histological and histomorphometric techniques. The results showed that the testes of 3- to 9-month-old birds were light pink while testes of sexually mature chicken were creamy white in colour. The left and right testicular weight, length, diameter, circumference and the organosomatic indices increased significantly (p < .05) with increasing age across the groups. Although the mean tubular diameter and epithelial height of the left and right seminiferous tubules increased significantly (p < .05) with age, the tubular diameter, epithelial height and luminal diameter did not vary significantly (p > .05) between the left and right testes of all the groups. The one-cell layer thick germinal epithelium of the left testes at 3 to 6 months old showed islands of cell proliferation that contained spermatogonia and spermatocytes. At 6 to 9 months, the left testes exhibited numerous early spermatids with occasional occurrence of late stage spermatids while the right testes showed scanty early stage spermatids. At 12 to 18 months, the germinal epithelia of both left and right testes were characterized by the presence of Sertoli cells, spermatogonia, primary spermatocytes, numerous early and late stage spermatids as well as spermatozoa. In conclusion, the morphological features highlighted in the present study show that at pre-pubertal periods, the left testes may develop faster than the right testes. However, both left and right testes may participate actively in the production of spermatozoa during the post-pubertal life.

Feeding, feed-seeking behavior, and reproductive performance of broiler breeders under conditions of relaxed feed restriction

Broiler breeders are feed restricted to optimize reproductive performance. A randomized controlled study was conducted to investigate the effect of increasing female broiler breeder BW on feeding, feed-seeking behavior, and reproductive performance. It was hypothesized that a greater BW would decrease feeding and feed-seeking behavior, and reduce reproductive performance. Ross 708 female broiler breeders (n = 36) were fed using a precision feeding system from 2 to 42 wk of age. Ten BW trajectories were created from a multiphasic Gompertz growth model that increased growth from 0 to 22.5% in the prepubertal and pubertal phases of growth, in 2.5% increments. Six unrestricted birds were not limited to a maximum BW. Body weight was evaluated as a 2-way ANOVA. Two linear regression analyses were conducted, one which included all birds and one which excluded the unrestricted birds. For the regression analyses, BW at photostimulation (22 wk of age) was used as the continuous independent variable to represent the degree of variation between trajectories. Differences were reported at P ≤ 0.05. Body weight increased as trajectory-specific BW targets increased from 6 to 28 wk of age. Differences of BW between BW trajectories decreased during the laying period, which was a result of individual bird variation within BW trajectories. Station visit frequency decreased per kilogram increase in BW for all birds during rearing and lay, and within feed-restricted birds during lay only. The number of meals and ADFI increased with age, which reflected nutrient intake to support maintenance, growth, and reproductive requirements. Mean egg weight (EW) of all birds increased by 0.72 g per kilogram increase in BW from 22 to 41 wk of age. From 22 to 29 wk of age, mean EW of feed-restricted birds increased by 2.78 g per kilogram increase in BW. For every kilogram increase in BW, age at first egg comparing all birds decreased by 10.83 d. Two unrestricted birds came into lay before photostimulation. In contrast with the hypotheses, BW increased up to 22.5% above the recommended target did not reduce feeding and feed seeking behavior, or negatively impact reproductive performance.

Histomorphological and endocrine assessment of female Arabian carpetshark, Chiloscyllium arabicum (Elasmobranchii: Hemiscylliidae) from the Persian Gulf during annual reproductive cycle

The present study aimed at assessing the annual reproductive cycle of female Arabian carpetshark, Chiloscyllium arabicum from the Persian Gulf by a macroscopic and microscopic evaluation of the reproductive tract. The annual cycle of gonadal steroids [17β-estradiol (E2), progesterone (P4) and testosterone (T)] was also assessed in this shark. In total, 130 female C. arabicum were collected from the Bahrakan Creek (located northwest of the Persian Gulf) between January 2018 and March 2019. Females were oviparous with an external-type ovary and only one functional ovary. Five sexual maturity stages were recognized based on macroscopic and microscopic evaluation: Immature I (August-October), Immature II (November-January), Mature (February-March), Pregnant (April-May) and Spent (June-July). The structural changes in the oviducts, oviducal glands and uterus throughout the annual reproductive cycle were consistent with their roles in the egg movement, the egg capsule production and sperm storage. The plasma levels of the gonadal steroids were associated with morphological changes in the reproductive tract. E2 showed two detectable peaks during March (close to ovulation) and June (just before mating). P4 and T displayed a peak just before ovulation.

Effect of age at photostimulation on sexual maturation and egg-laying performance of layer breeders

The objective of this study was to determine the effect of age at photostimulation on sexual maturity and performance of layer breeders. A total of 192 fourteen-wk-old White Leghorn (WL) breeder hens were randomly allocated to 4 treatments of 48 birds each, with 2 replicates per treatment. The birds were photostimulated at 16 (PS16), 18 (PS18), 20 (PS20), and 22 (PS22) wk of age. Four birds per treatment were randomly selected to evaluate sexual organ development at 1 D before photostimulation and 2, 4, and 6 wk after photostimulation. The ovary weight, large yellow follicles number (LYF), oviduct weight, and oviduct length of PS18 increased sharply after photostimulation. Conversely, the increase in PS16 was not observed until 2 wk after photostimulation. There was no difference in age at sexual maturity between treatments (P > 0.05). The PS16 had the longest interval (28 D) from photostimulation to 5% egg production, while PS22 reached 5% egg production 7 D before photostimulation. The PS22 had lower peak production (P = 0.02) and less egg production (P = 0.02) than other treatments. The PS16 had more broken and abnormal eggs (P = 0.01) and lower hatchability (P = 0.04) than other treatments. In conclusion, photostimulation at 16 and 22 wk of age decreases hatchability and egg production, respectively, and photostimulation at 18 wk is appreciated for the WL breeder hens.

Gene Expression Profiling in Ovaries and Association Analyses Reveal HEP21 as a Candidate Gene for Sexual Maturity in Chickens

Simple Summary

Chicken meat and egg productions are essential for human beings. Sexual maturity is important for both egg production and meat flavor. It is necessary to elucidate the genetic mechanism of chicken sexual maturity. In current study, we used digital gene expression (DGE) RNA-sequencing analysis to investigate differential expression of genes in pre-pubertal and post-pubertal ovaries in two different sub-breeds of chicken with different onsets of sexual maturity. After the analysis of RNA-sequencing data, numerous differentially expressed genes were found in both comparisons (32 day old, early-sexual-maturity pre-laying hens (P-F-O1) vs. 103 day old early-sexual-maturity laying hens (P-F-O2), and 32 day old late-sexual-maturity pre-laying hens (L-F-O1) vs. 153 day old late-sexual-maturity pre-laying hens (L-F-O2)). With the bioinformatic analysis, hen egg protein 21 kDa (HEP21) was chosen as the candidate gene to conduct following experiment. The variations in HEP21 were screened and association analyses between rs315156783 and reproductive traits were investigated in fifth-generation Ningdu Yellow chickens from a closely bred population. These results demonstrated that HEP21 is a candidate gene for sexual maturity and ovary development in chickens. However, the underlying mechanism of how HEP21 regulates chicken sexual maturity needs further focused studies.

Abstract

The age of onset of sexual maturity is an important reproductive trait in chickens. In this study, we explored candidate genes associated with sexual maturity and ovary development in chickens. We performed DGE RNA-sequencing analyses of ovaries of pre-laying (P-F-O1, L-F-O1) and laying (P-F-O2, L-F-O2) hens of two sub-breeds of Ningdu Yellow chicken. A total of 3197 genes were identified in the two comparisons, and 966 and 1860 genes were detected exclusively in comparisons of P-F-O1 vs. P-F-O2 and L-F-O1 vs. L-F-O2, respectively. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses showed that genes involved in transmembrane signaling receptor activity, cell adhesion, developmental processes, the neuroactive ligand–receptor interaction pathway, and the calcium signaling pathway were enriched in both comparisons. Genes on these pathways, including growth hormone (GH), integrin subunit beta 3 (ITGB3), thyroid stimulating hormone subunit beta (TSHB), prolactin (PRL), and transforming growth factor beta 3 (TGFB3), play indispensable roles in sexual maturity. As a gene unique to poultry, hen egg protein 21 kDa (HEP21) was chosen as the candidate gene. Differential expression and association analyses were performed. RNA-seq data and qPCR showed that HEP21 was significantly differentially expressed in pre-pubertal and pubertal ovaries. A total of 23 variations were detected in HEP21. Association analyses of single nucleotide polymorphisms (SNPs) in HEP21 and reproductive traits showed that rs315156783 was significantly related to comb height at 84 and 91 days. These results indicate that HEP21 is a candidate gene for sexual maturity in chickens. Our results contribute to a more comprehensive understanding of sexual maturity and reproduction in chickens.

Effect of age at photostimulation on reproductive performance of Beijing-You Chicken breeders

This work studied the effect of age at photostimulation on reproductive performance of Beijing-You Chicken (BYC) breeders. A total of 384 fourteen-week-old BYC breeder hens were randomly allocated to 4 treatments of 96 birds each, with 2 replicates per treatment. The treatments represent photostimulation at 16, 18, 20, and 22 wk of age, respectively (PS16, PS18, PS20, and PS22) by incrementally increasing day length from 8L:16D to 14L:10D and by increasing lighting intensity from 10 to 80 lx. Egg production was recorded for each replicate until 51 wk. Four birds randomly selected from each treatment were sacrificed to characterize sexual organ development at 4 time points: 1 D before photostimulation and 2, 4, and 6 wk after photostimulation. Eggshell quality at peak laying was measured. The results showed that the changes in ovary and oviduct weight in PS22 were 8.68- and 4.27-fold higher than in PS16 at 6 wk after photostimulation. PS16 had an earlier age at 5% egg production than PS20 and PS22 (P = 0.003). The interval from photostimulation to age at 5% egg production in PS20 and PS22 was shorter than in other treatments (P = 0.005). Later peak egg production was seen in PS20 (211.0 D) and PS22 (218.0 D) than in PS16 (183.0 D) and PS18 (190.0 D, P = 0.020), but the laying rate of PS20 decreased slowly after peak laying. PS20 and PS22 had higher egg weights than PS16 and PS18 at peak laying (P = 0.018). Age at photostimulation had no effect on egg number, defective egg number, or hatchability (P > 0.05). In summary, the onset of lay can be advanced by photostimulation at early ages, but there is no difference on egg production until 51 wk. Photostimulation at 20 wk improves peak of laying and laying uniformity.

A model of pre-pubertal broiler breeder estradiol-17β levels predicts advanced sexual maturation for birds with high body weight or short juvenile day-length exposure

As broiler breeders face increased reproductive challenges specifically related to overfeeding, a clear understanding of the physiological effects of BW and rearing photoperiod on reproductive development is needed. The objective was to use mathematical models to compare plasma estradiol-17β (E2) concentration to characterize the effect of BW and rearing photoperiod on E2 levels. A 2 × 3 factorial arrangement of treatments was used. Hens (n = 180) were fed with a precision feeding system to allocate feed individually to achieve the breeder-recommended BW curve (Standard) or to a BW curve reaching the 21 wk target at 18 wk (High). Hens were on 8L:16D, 10L:14D, or 12L:12D photoschedules during rearing and were photostimulated at 21 wk. Age at first egg (AFE) was recorded. Plasma E2 levels were determined weekly between week 20 and 28. Two modified Gompertz models described E2 level as a function of (a) chronological or (b) physiological (relative to AFE) age. Timing of E2-inflection point was compared between models and treatments. Differences were reported as significant at P ≤ 0.05. The chronological age model inferred that High BW reduced the duration between the E2-inflection point and AFE, whereas the physiological age model inferred that High BW only reduced the duration between photostimulation and the E2-inflection point. Hens on the Standard BW treatment had a longer period between photostimulation and the E2-inflection point compared to hens on the High-BW treatment (11.03 vs. 1.50 wk, respectively, based on physiological age). Hens on the 12L:12D photoschedule had a longer period between photostimulation and the E2-inflection point compared to hens on the 8L:16D or 10L:14D photoschedule, both in the Standard and High BW (28.91 vs. 1.78 and 2.40 wk, 2.65 vs. 0.93 and 0.94 wk, respectively, based on physiological age). The described methodology and results provide quantitative insight into E2 dynamics and serves as a model for future endocrinological studies in poultry reproduction.

Follicular Development and Reproductive Characteristics in Four Species of Brazilian Tropidurus Lizards

The follicular development and reproductive characteristics of four species of oviparous lizards in the Tropidurus torquatus group were anatomically and histologically evaluated. We measured specimens, recorded the number of follicles and eggs, and removed the right ovary of each individual, which we processed according to histological routine and photo-documented. For all species, ovaries were divided into a cortical germinal bed, where oogonia and stage I oocytes are located, and a medullar stroma, where the remaining follicular developmental stages occur. Microscopic analysis did not show differences in ovarian follicle development for the four species of the T. torquatus group. The only measurement that presented significant variation throughout follicular development was the thickness of the granulosa layer in stage VII follicles. Regarding snout-tovent length at sexual maturity, few variations were observed among the species, with the smallest length recorded for T. oreadicus. Clutch size was higher for T. itambere and T. torquatus species, with a maximum of five and six eggs in the oviducts, respectively. Tropidurus oreadicus and T. hispidus had a maximum of five and six follicles, respectively, but neither species presented eggs in the oviducts. In addition, the reproductive activity varied among the four lizard species of the T. torquatus group. Finally, besides the morphological characteristics observed among these species, this is the first study to report data on the germinal bed, number of ovarian follicles, corpus luteum, and follicular atresia in relation to reproductive activity.

Ecology of the growth of Anolis nebulosus (Squamata: Dactyloidae) in a seasonal tropical environment in the Chamela region, Jalisco, Mexico

Juvenile growth rates are thought to be restricted by available food resources. In animals that grow throughout the year, such as tropical lizards, growth is therefore predicted to be faster during the rainy season. We test this prediction using a population of Anolis nebulosusby describing the growth trajectories of both sexes using nonlinear regression models, and we then correlate the growth rates of individuals with food available in the environment, precipitation, and temperature. The Von Bertalanffy model fits the growth rates of the females better, while the logistic-by-length model fits the males better. According to both models, the males grew faster than females, reaching slightly smaller sizes at adulthood. Males reached sexual maturity when 35 mm long, at an age of seven months, and females matured at 37 mm (SVL), taking nine months to reach this size. In 1989, juvenile males and females grew more in both seasons (rainy and dry) than adults; for 1990, there were no differences by season or between age classes. These results are interesting since in the 1989 and 1990 rainy seasons, practically the same orders of prey and the greatest abundance of prey available in the environment were registered. A possible explanation could be that predation was more intense in 1990 than in 1989. There is little evidence that food, temperature, and humidity affect growth rates of A. nebulosus, refuting our predictions. This is mainly due to the low variation in growth observed in 1990. Therefore we think that the growth of this species reflects a complex combination of ecological and genetic factors.

Postmenarcheal irregularities in menstrual cycle in adolescent girls

The first menstrual bleeding, referred to as menarche, albeit an important point in a woman's life, does not yet mean her full sexual maturity. The hypothalamus-pituitary-ovary axis is fragile during this period and depends on many factors. Their mutual interplay occurs individually and gradually over the next few years, therefore menstrual irregularities of the menstrual cycle occur physiologically, and not all of them need to be regulated. However, it is one of the most frequent reasons for visiting a paediatric gynaecologists office. The average age of menarche in girls in the Czech Republic is 12 years and 6 to 9 months, the physiological limits are 10-15 years. After menarche, anovulation cycles are predominating, resulting in estrogenic activity not controlled by gestagen, which may result in dysfunctional bleeding with subsequent anaemia from blood loss. The opposite possible problem is the absence of menstruation, either primary or secondary. Correct complete gynaecological examination of adolescent girls with a purposefully thought-out next schematic of laboratory, imaging and counselling examinations leads to the correct diagnosis. This article clearly outlines and breaks down the most common disorders. The paediatric gynaecologist chooses "tailor-made" treatment with respect to the patients age, always strictly individual and justified. Keywords: sexual maturity, menarche, menstrual cycle, hormonal cytology, menstrual disorder, anovulation.

Ontogenetic Change in the Venom of Mexican Black-Tailed Rattlesnakes (Crotalus molossus nigrescens)

Ontogenetic changes in venom composition have important ecological implications due the relevance of venom in prey acquisition and defense. Additionally, intraspecific venom variation has direct medical consequences for the treatment of snakebite. However, ontogenetic changes are not well documented in most species. The Mexican Black-tailed Rattlesnake (Crotalus molossus nigrescens) is large-bodied and broadly distributed in Mexico. To document venom variation and test for ontogenetic changes in venom composition, we obtained venom samples from twenty-seven C. m. nigrescens with different total body lengths (TBL) from eight states in Mexico. The primary components in the venom were detected by reverse-phase HPLC, western blot, and mass spectrometry. In addition, we evaluated the biochemical (proteolytic, coagulant and fibrinogenolytic activities) and biological (LD₅₀ and hemorrhagic activity) activities of the venoms. Finally, we tested for recognition and neutralization of Mexican antivenoms against venoms of juvenile and adult snakes. We detected clear ontogenetic venom variation in C. m. nigrescens. Venoms from younger snakes contained more crotamine-like myotoxins and snake venom serine proteinases than venoms from older snakes; however, an increase of snake venom metalloproteinases was detected in venoms of larger snakes. Venoms from juvenile snakes were, in general, more toxic and procoagulant than venoms from adults; however, adult venoms were more proteolytic. Most of the venoms analyzed were hemorrhagic. Importantly, Mexican antivenoms had difficulties recognizing low molecular mass proteins (<12 kDa) of venoms from both juvenile and adult snakes. The antivenoms did not neutralize the crotamine effect caused by the venom of juveniles. Thus, we suggest that Mexican antivenoms would have difficulty neutralizing some human envenomations and, therefore, it may be necessary improve the immunization mixture in Mexican antivenoms to account for low molecular mass proteins, like myotoxins.

Longevity and sexual maturity vary across species with number of cortical neurons, and humans are no exception

Maximal longevity of endotherms has long been considered to increase with decreasing specific metabolic rate, and thus with increasing body mass. Using a dataset of over 700 species, here I show that maximal longevity, age at sexual maturity, and postmaturity longevity across bird and mammalian species instead correlate primarily, and universally, with the number of cortical brain neurons. Correlations with metabolic rate and body mass are entirely explained by clade-specific relationships between these variables and numbers of cortical neurons across species. Importantly, humans reach sexual maturity and subsequently live just as long as expected for their number of cortical neurons, which eliminates the basis for earlier theories of protracted childhood and prolonged post-menopause longevity as derived human characteristics. Longevity might increase together with numbers of cortical neurons through their impact on three main factors: delay of sexual maturity, which postpones the onset of aging; lengthening of the period of viable physiological integration and adaptation, which increases postmaturity longevity; and improved cognitive capabilities that benefit survival of the self and of longer-lived progeny, and are conducive to prolonged learning and cultural transmission through increased generational overlap. Importantly, the findings indicate that theories of aging and neurodegenerative diseases should take absolute time lived besides relative "age" into consideration.

Characteristics of Female Germline Stem Cells from Porcine Ovaries at Sexual Maturity

Pigs share many anatomical and physiological features with humans, offering a unique and viable model for biomedical research. Although porcine female germline stem cells (FGSCs) were identified in the juvenile ovary, no reports described the isolation and purification of FGSCs from the pig at sexual maturity. Here, we isolated, purified, and cultured FGSCs from porcine ovaries at sexual maturity. Furthermore, we established and characterized the porcine FGSC (pFGSC) lines. In addition, we found that pFGSC lines could differentiate into oocytes when injection into tissue grafts, including human ovarian tissues. The results show that FGSCs exist in ovaries of Banna mini-pigs at juvenile and sexually maturity. These findings have implications in animal biotechnology applications and regeneration medicine.

Growth patterns for three generations of an intercross between red junglefowl and chickens selected for low body weight

Growth is a complex and dynamic process that may be measured at a specific point or over a period of time. Compared was the growth of male and female chickens over a three-generation period. Involved were red junglefowl (RJF; Gallus gallus), a line of White Plymouth Rock chickens (LWS; Gallus gallus domesticus) selected for low body weight, and their reciprocal F1 and F2 crosses. In both sexes, Gompertz's description of growth showed that RJF had significantly lower asymptotes, earlier inflection points, and faster growth rates than LWS. Heterosis for these measures was positive for asymptote and negative for growth rate and inflection point. The RJF commenced egg production at a significantly younger age and lower body weight than LWS. Although F1 and F2 reciprocal crosses were similar for body weight and for age at first egg, the F1 reciprocal crosses began lay at significantly younger ages than the F2 crosses and parental lines. When viewed on a physiological basis where age and body weight were simultaneously standardized, both parental lines and reciprocal F1 and F2 crosses had differing rapid and lag growth phases. Overall, sexual dimorphism increased in all populations from hatch to sexual maturity. The LWS males had a longer growth period consistent with their female counterparts who became sexually mature at older ages. Comprehensively, these results indicate additive and nonadditive genetic variation for distinct growth patterns and changes in resource allocation strategies over time.

Reproductive biology of female striped marlin Kajikia audax in the western Pacific Ocean

Length and mass data for 1260 (536 females, 683 males, 41 sex unknown) striped marlin Kajikia audax were collected at the fish markets of Tungkang, Singkang and Nanfangao from July 2004 to September 2010. Of these samples, 534 gonads (236 females and 298 males) ranging from 95 to 206 cm in eye-to-fork length (L_EF ) and 8 to 88 kg in round mass (M_R ), were collected. Chi-square tests indicated sex ratios were homogeneous among months in 2004 and 2006-2008, but not in 2005, 2009 and 2010; and there were significant differences in sex ratio by size. The overall sex ratio (R_S ) differed significantly from the expected 0·5. Kajikia audax are sexually dimorphic and the proportions of females increased with size between 140 and 210 cm L_EF . Reproductive activity was assessed using a gonado-somatic index (I_G ), external appearance of the gonads and histological examination and results indicated that the spawning season occurred from April to August with a peak in June to July. Based on histological observations and the distribution of oocyte diameters, K. audax are multiple spawners and their oocytes develop asynchronously. The estimated length-at-50% maturity (L_EF50 ) was c. 181 cm (c. 4·8 years of age) for females. The proportion of reproductively active females in the spawning season with ovaries containing postovulatory follicles (0·27) indicated that they spawned every 3·7 days on average. The hydrated oocyte method estimated mean ± S.D. batch fecundity (F_B ) to be 4·4 ± 2·02 million eggs; average relative fecundity was 53·6 ± 13·9 oocytes g^-1 M_R ; and the average annual fecundity was 181·3 ± 48·3 million eggs. The parameters estimated in this study are key information for stock assessments of K. audax in the north-western and central Pacific and will contribute to the conservation, management and sustainable yield of this species.

Histological Characteristics on the Testes of Mud Spiny Lobster, Panulirus polyphagus (Herbst, 1793)

BACKGROUND AND OBJECTIVE

Mud spiny lobsters, Panulirus polyphagus (P. polyphagus) are one of the most important fisheries resources now-a-days due to quality that it's possessed. However, there is still lack of in-depth study about this species mainly on males testicular characteristics and sexual maturity size. Therefore, the present study was carried out to investigate the histological characteristics on the testes and sexual maturity sizes of mud spiny lobster, Panulirus polyphagus.

MATERIALS AND METHODS

The testes were dissected out and fixed in 10% buffered formalin solution for 11 h, dehydrated in 70% alcohol and lastly placed in tissue processor for 18±1 h at 60°C. The tissues blocks were cut at the thickness of 4 μm on a rotary microtome. Stained tissues were taken under Advance Microscope (Nikon Eclipse 80i Nomarski DIC). Collected data were analyzed using Microsoft Excel 2013. Data were presented as mean±standard deviation. Statistical analyses were done using one-way ANOVA using SPSS (Version 22).

RESULTS

These lobules of mature P. polyphagus were formed via different germinative lineage cells such as spermatogonia, spermatocytes, spermatids and spermatozoa. The histological characteristics of testes showed that the process of spermatogenesis went through the stages of four testes maturation which were spermatogonia I and II, spermatocytes I and II, spermatids and spermatozoa stages within different body weight of P. polyphagus. It was found that there were significant difference between body weight and carapace length to the testicular maturation stages (one-way ANOVA and p = 0.000).

CONCLUSION

The results of this experiment indicated that males P. polyphagus have four stages of testes maturation and can be considered to have fully mature testes that ready for fertilization at 452 g body weight (BW) and 107 mm carapace length (CL) or more.

Maternal Overweight Disrupts the Sexual Maturation of the Offspring

The aims of the present work were to study the effect of maternal overweight and obesity on the ovarian reserve, follicular development, and ovulation of the offspring and to assess whether this maternal condition alters oocyte integrity. To this end, female offspring from rats fed standard (OSD) or cafeteria (OCD) diet were used. Body weight, vaginal opening, and estrous cycle were recorded and ovaries were obtained on the day of the second estrus. In addition, ovarian weight, ovulation rate (measured by the number of oocytes within oviducts), follicular development (determined by histology), and oocyte integrity were examined. The OCD were divided into 2 groups: offspring from rats with 17% and 28% of overweight (OCD17 and OCD28, respectively). Both OCD groups showed higher body weight, but OCD28 also exhibited early vaginal opening and higher ovarian weight and glycemia at euthanasia compared with OSD. Both OCD17 and OCD28 had lower number of primordial and primary follicles, and only OCD28 exhibited lower number of antral follicles, all compared with OSD rats. In addition, both OCD17 and OCD28 had higher ovulation rate than controls, and OCD28 had lower number of healthy oocytes, which, in turn, exhibited morphological alterations such as larger perivitelline space and zona pellucida than those of control animals. These results suggest that maternal overweight may severely affect the reproductive ability of the offspring, likely as a result of altering the organogenesis.

Is age of menarche among school girls related to academic performance?

Background There is strong evidence that the mean age of menarche has declined over the last few decades in developed and developing countries. This is of a major concern because of its enormous public health implications. This study aimed to estimate the age of menarche in Kuwait and investigate the association between menarcheal age and academic performance among high school girls in Kuwait. Methods A cross-sectional study was conducted on randomly selected female high school students from private and public high schools in all governorates in Kuwait. Data on the age of menarche were collected by self-administered questionnaire from the students, while data on academic performance were extracted from the students' academic records. Results Of the 907 students we selected, 800 (88.2%) responded. The mean age of menarche was 12.33 [95% confidence interval (CI) 12.18-12.49] years. There was no evidence for significant association between age of menarche and students' academic performance before or after adjusting for potential confounders. Conclusion The calculated age of menarche among contemporary girls in Kuwait is similar to that of the girls in industrialized countries. Early menarcheal age is unlikely to lead to adverse behavior that may affect academic performance in our setting.