Incidence Of Atresia Research Articles

Fecundity strategy of the highly exploited limpet Patella ordinaria from an oceanic archipelago

Limpet harvesting dates to the 15th century in Madeira archipelago (NE Atlantic Ocean). This activity is size-selective, removing older and larger individuals with greater commercial value. It can lead to a lower reproductive output as individual fecundity is size-dependent. The decrease of limpet populations has led to the implementation of a series of management measures including a closed season during the reproductive season (November–March). So far, sizes and the reproductive parameters, size and age at first maturity, have been previously used to determine the exploitation status of Patella ordinaria in Madeira archipelago, with no study performed on the reproductive strategy of this limpet. This is pivotal to comprehend the population dynamics of any species, being fecundity one of the reproduction parameters that should be analysed. This work aims to provide for the first time data on the fecundity of P. ordinaria. An average of 17 females per month were randomly collected over the spawning 2021/2022 season from the subtidal rocky shores of the Madeira archipelago. Four criteria were analysed over the spawning season: (i) the presence of a hiatus between pre- and vitellogenic oocytes; (ii) the number and (iii) mean size of advanced vitellogenic oocytes; and (iv) the incidence of atresia. A hiatus between pre- and vitellogenic oocytes across the spawning season was observed. An increasing trend in the number of vitellogenic oocytes was observed over the spawning season. The size of vitellogenic oocytes showed significant differences among months and the relative intensity of atresia varied from 7.86 to 20.79%. The information on the fecundity strategy leads to a better understanding of the reproductive capacity of this species. It also identifies the best approach for future estimations of relative annual fecundity estimations, with direct implications on the sustainable exploitation of this commercial species.

Distal Recurrent Tracheoesophageal Fistula after Repair of Esophageal Atresia-Incidence, Risk Factors, and Outcome.

The aim of this study was to assess incidence, risk factors, and outcomes of distal recurrent tracheoesophageal fistula (RTEF) after repair of esophageal atresia (EA). Ethical consent was obtained. Data collection was done by review of hospital records of 286 patients (268 in-house and 18 referred) who underwent repair of type C or D EA from 1980 to 2021. Spitz class, long-gap (tracheoesophageal fistula at carina), fundoplication, leakage, and stricture were assessed as RTEF risk factors. Outcome measures were long-term closure of RTEF, retainment of native esophagus, and survival. RTEF occurred in 23 patients (19 in-house) with type C (n = 22) or type D (n = 1) EA with median 4.4 (interquartile range [IQR]: 1.7-13) months after repair. Five patients had late RTEF 3.5 to 16 years after repair. Nineteen (7.3%) in-house patients developed RTEF. Presenting symptoms, age at diagnosis, and presence of anastomotic stricture (AS) are listed. No statistically significant risk factors were found, risk ratio of 0.5 to 2.7 (IQR: 0.1-8.7), p-value of 0.25 to 0.75. Detached closure clip and esophageal foreign body contributed to RTEF in two patients. Sixteen patients underwent rethoracotomy for closure of RTEF, 5 (22%) with AS eventually underwent esophageal reconstruction after a period with cervical esophagostomy. Two patients with late-manifested RTEFs underwent closure with laser cauterization. In 22 patients, treatment of RTEF succeeded, whereas 1 (4%) premature patient died of instant re-RTEF. RTEF had an incidence of 7% with diverse patterns of manifestation and predicting factors. Closure rate and patient survival were excellent, but RTEF with AS predicted loss of native esophagus.

Gonadal Atresia, Estrogen-Responsive, and Apoptosis-Specific mRNA Expression in Marine Mussels from the East China Coast: A Preliminary Study

This preliminary survey analysed mussel atresia incidences, estrogen-responsive and apoptotic-specific molecular end points, and aqueous and gonadal levels of selected estrogens from the East China coast. Estrogen levels were low (e.g. < LOD-28.36 ng/L, < LOD-3.88 ng/g wet weight of tissue for BPA) relative to worldwide freshwater environments, but high oocyte follicle atresia incidences (up to 26.6%) occurred at selected sites. Expression of estrogen-responsive ER2 was significantly increased in males relative to females at sites with high atresia incidences in females. A second estrogen-responsive gene, V9, was significantly increased at two sites in April in females relative to males; the opposite was true for the remaining two sites. Apoptosis-specific genes (Bcl-2, fas) showed elevated expression in males relative to females at the site with the highest atresia incidence. These results provide coastal estrogen levels and the utility of several estrogen-specific molecular-level markers for marine mussels.

Current status of assisted reproductive technologies in buffaloes.

Buffaloes are raised by small farm holders primarily as source of draft power owing to its resistance to hot climate, disease, and stress conditions. Over the years, transformation of these animals from draft to dairy was deliberately carried out through genetic improvement program leading to the development of buffalo-based enterprises. Buffalo production is now getting more attention and interest from buffalo raisers due to its socioeconomic impact as well as its contribution to propelling the livestock industry in many developing countries. Reproduction of buffaloes, however, is confronted with huge challenge and concern as being generally less efficient to reproduce compared with cattle due to both intrinsic and extrinsic factors such as poor estrus manifestation, silent heat, marked seasonal infertility, postpartum anestrus, long calving interval, delayed puberty, inherently low number of primordial follicles in their ovaries, high incidence of atresia, and apoptosis. Assisted reproductive technologies (ARTs) are major interventions for the efficient utilization of follicle reserve in buffaloes. The present review focuses on estrus and ovulation synchronization for fixed time artificial insemination, in vitro embryo production, intracytoplasmic sperm injection, cryopreservation of oocytes and embryos, somatic cell nuclear transfer, the factors affecting utilization in various ARTs, and future perspectives in buffaloes.

Prenatal exposure to an environmentally relevant phthalate mixture alters ovarian steroidogenesis and folliculogenesis in the F1 generation of adult female mice

Phthalates are a family of chemicals that can be found in plastic and personal care products used by consumers every day and they are known endocrine disrupting chemicals that can disrupt female reproduction. In previous studies, an environmentally relevant phthalate mixture was shown to affect female reproduction in a transgenerational manner. However, limited information was available on the effect of phthalate mixtures on ovarian steroidogenesis and folliculogenesis. Ovarian steroidogenesis is important for producing hormones needed for reproduction and ovarian regulation, and folliculogenesis is essential for the development of ovarian follicles and successful fertility. Thus, this study tested the hypothesis that prenatal exposure to an environmentally relevant phthalate mixture adversely affects ovarian steroidogenesis and folliculogenesis in the F1 generation of adult female mice. Pregnant dams (F0 generation) were orally dosed with vehicle control or a phthalate mixture (20 μg/kg/day-500 mg/kg/day) daily from gestational day 10 to birth, and the adult F1 females were the offspring of the dosed dams. The ovaries of the F1 generation were collected at postnatal day 60. One ovary was used for histological examination of the numbers and percent of different follicle types. The other ovary was used to measure expression of theca and granulosa cell enzymes. Additionally, sera were collected for measuring hormone levels. The results indicate that prenatal exposure to the phthalate mixture decreases hormone levels and gene expression, alters the transitioning of follicle types, and leads to a higher incidence of atresia in the F1 generation offspring.

Quantification of the Ovarian follicles of water buffaloes (Bubalus bubalis)

Ovarian samples were collected either through ovariectomy or slaughtering of Phillipine water buffaloes at the Phillipine Carabao Research and development Centre (now Phillipine Carabao Centre), Central Luzon State University, Philippines. From the young buffalo (6-7months, 2 pairs of ovaries); pubertal (2 year; n=1 pair); adults (7-8 year; n=3 Pairs) and old (12-14 years; n=3 pairs) were used for the study. The ovaries were fixed, dehydrated and embedded in the paraffin wax and were serially sectioned at 10 microns. The sectioned ovaries were then stained with periodic acid/schiff's-Hematoxylin (PAS-H). Ovarian follicles of the following categories (primary, growing, secondary, tertiary, and atretic) were quantified in the young, puberial, adults and old water buffaloes. In the young and pubertal buffaloes, the average follicular population of 75,604 and 85, 358 primary follicles were counted, respectively. The number of primary follicles decreased as age of the animal increased, meaning the follicles are either ovulated or became atretic during the course of the estrous cycle. The growing follicles were highest in the pubertal animals with an average follicle of 7, 317 which is 8. 75 percent of the primordial follicles. The young and adult buffaloes had an average count of 71 and 18 growing follicles respectively. The tremendous increase in the number of the growing follicles during the pubertal stage may indicate that follicle are continually being recruited and they grow from stage to stage and end life by becoming atritic or ovulated. The number of secondary follicles found in the pubertal revealed that there was a transition of the growing follicles to the secondary stage. Further decline in the number of tertiary follicles occurred, while the average number for the tertiary follicles in the young, adult and old were 3, 9, 7, respectively which is quite low. Data showed that there was a high incidence of atresia occurring in the ovarian follicles of buffaloes ranging from 127 in the young to 142 in the pubertal.

Pediatric Biliary Atresia: Prenatal and Postnatal Risk Factors

Background: Biliary atresia is the most common cause of cholestasis in infants caused by intrauterineand neonatal inflammatory process leads to progressive biliary tract obstruction and fibrosis. Risk factorsare expected to contribute in the disease type. Many studies have been done to determine the risk factorsof biliary atresia. Yet, there is still limited information about risk factors in Indonesia. This study aims todetermine the risk factors contributing to biliary atresia in East Java, Indonesia.Methods: This cross-sectional study collected 219 medical record data of cholestasis patients during January2010 to April 2017 that met the inclusion criteria. 85 of them were diagnosed with biliary atresia. Selectedprenatal and postnatal risk factor were evaluated and analyzed.Result: There were significant results in maternal age on pregnancy (p= 0.009), parity (p= 0.035), andgestational age (p= 0.005) among 85 patients which were diagnosed with biliary atresia. The regression testshowed significant result on those 3 factors.Conclusion: Maternal age on pregnancy, parity, and gestational age are the prenatal and postnatal riskfactors that contribute to the biliary atresia incidence. These results are expected to be used as one of theproviding information regarding prenatal and postnatal risk factors for pediatric biliary atresia in East Java,Indonesia

Nationwide population-based study showed that the rotavirus vaccination had no impact on the incidence of biliary atresia in Korea.

Rotaviruses have been associated with biliary atresia. This study investigated whether the rotavirus vaccine, which was introduced to Korea in 2008, had an impact on the incidence of biliary atresia. We identified all rotavirus infections (n=436826) and biliary atresia cases (n=528) diagnosed from 2006 to 2015 from insurance and health databases. The annual and seasonal incidence of biliary atresia and rotavirus infection rates in neonates and children were calculated. The difference in the risk of biliary atresia between rotavirus-infected and non-infected neonates was analysed. The incidence of rotavirus infections was 20.6 versus 13.4 per 1000 cases before (2006-2008) and after (2009-2015) vaccine implementation. However, neonatal rotavirus infection rates did not decrease, with an incidence of 14.5 versus 14.8 per 1000 cases before and after vaccination. The biliary atresia incidence remained constant at 12.0 per 100000 cases. Rotavirus infections in neonates were a risk factor for biliary atresia (odds ratio 3.14, 95% confidence interval 1.87-5.26). Rotavirus vaccination had no impact on the incidence of biliary atresia, possibly because the vaccination did not change the neonatal rotavirus infection rate through herd immunity. However, rotavirus infections in neonates were significantly associated with biliary atresia.

Fecundity regulation strategy of the blue jack mackerel, Trachurus picturatus (Bowdich, 1825), off Madeira Island (NE Atlantic)

This contribution intends to verify the type of fecundity regulation of the blue jack mackerel. For this purpose, the oocyte development process was analysed. A total of 158 ovaries were sampled between January 2009 and April 2010 from purse-seiners operating in the Madeira Island waters, NE Atlantic Ocean. Histological analysis and visual image analysis system were used to study the four main criteria applied for fecundity type determination: (1) presence of a hiatus between pre-vitellogenic and vitellogenic oocytes; (2) number of standing stock of advanced vitellogenic oocytes over the spawning season; (3) mean size of standing stock of advanced vitellogenic oocytes over the spawning season; and (4) the incidence of atresia over the spawning season. The analysis of the oocytes size frequency distribution showed that no distinct hiatus could be observed between pre-vitellogenic and vitellogenic oocytes during the spawning season. Considering the whole spawning period but the last month that was poorly sampled, the number of standing stock of advanced vitellogenic oocytes showed no decrease trend along the spawning season, the mean diameter of cortical alveoli oocytes and of the advanced stock of vitellogenic oocytes did not increase over the spawning season and the relative intensity of atresia was always high throughout this period. These findings suggest the blue jack mackerel displays an indeterminate fecundity.

PWE-137 The epidemiology and outcome of biliary atresia in scotland 2002–2013

Introduction Biliary atresia (BA) is a rare and poorly understood liver disease of infancy that is fatal if not treated through early biliary drainage via the Kasai procedure. BA surgery was rationalised to three UK centres in 2002 following data supporting improved outcomes in institutions performing greater than five Kasai procedures per year. 1 We have previously shown that outcomes in Scottish children were worse than expected in the years following initial rationalisation. 2 We aimed to expand the post-rationalisation cohort of BA cases in Scotland to examine epidemiology and outcomes. Method Outcomes of the previously published 2002–2009 incident cohort 2 was first expanded. New incident cases of BA, with a Scottish postcode at birth and born between 2010–2013, were obtained using data from specialist nurse/team knowledge in the three Scottish regional paediatric gastroenterology networks. New data collection focussed on demographics, details of Kasai and outcomes (particularly 2 year transplant-free survival [2YTFS]). Accurate regional and national population data was obtained from the General Register Office for Scotland and statistics performed in R with Poisson regression analysis for incidence trends. Results 48 infants were initially identified, of whom 5 were excluded from outcome analysis (three with Kasai procedures performed in Edinburgh, one with less than 1 yr follow up post-Kasai and one child born outside Scotland). Three infants required immediate liver transplantation; 43 infants underwent Kasai. Median age at Kasai in the full cohort was 56 days (IQR 47–65) and showed significant improvement from 61 days in 2002–2009 to 51 days in 2010–2013 (p = 0.014). Of those with available data, 61% cleared their jaundice (bilirubin Conclusion BA atresia incidence appears relatively stable in Scotland but with an unexplained cluster of cases in the Lanarkshire region; examination of this cluster may provide epidemiological insight into disease pathogenesis There was a significant reduction in time to Kasai portoenterostomy, with the 2YTFS improving since 2002–2009 cohort but is still lower than the pre-rationalisation figure of 65%. 2 Disclosure of interest None Declared. References McKiernan P, et al . Lancet. 2000;355(9197):25-29 Tayler R, et al . Arch Dis Child. 2013;98(5):381-383

G360 The epidemiology and outcome of biliary atresia in scotland 2002–2013

Background Biliary atresia (BA) is a rare, poorly understood liver disease of infancy that is fatal if not treated through early biliary drainage via the Kasai procedure. BA surgery was rationalised to three UK centres in 2002 following data supporting improved outcomes in institutions performing >5 Kasai per year. We have previously shown that outcomes in Scottish children were worse than expected in the years following initial rationalisation. Aims We aimed to expand the post-rationalisation cohort of BA cases in Scotland to examine epidemiology and outcomes. Methods Outcomes of the previously published 2002–2009 incident cohort was first expanded. New Scottish incident cases of BA born between 2010–2013, were obtained using data from specialist nurse/team knowledge. New data collection focussed on demographics, details of Kasai and outcomes (particularly 2 year transplant-free survival [2YTFS]). Accurate regional and national population data was obtained from the General Register Office for Scotland and statistics performed in R with Poisson regression analysis for incidence trends. Results 48 infants were initially identified, of whom 5 were excluded from outcome analysis (three with Kasai performed in Edinburgh, one with Conclusion BA atresia incidence appears relatively stable in Scotland but with an unexplained cluster of cases in Lanarkshire; examination of this cluster may provide epidemiological insight into disease pathogenesis Despite a significant reduction in time to Kasai, the 2YTFS in Scotland remains disappointing, is lower than the pre-rationalisation figure of 65% and is not currently an endorsement of centralisation of BA surgery in Scotland.

Malathion-induced granulosa cell apoptosis in caprine antral follicles: an ultrastructural and flow cytometric analysis.

Organophosphate pesticides (OPs) like malathion interfere with normal ovarian function resulting in an increased incidence of atresia and granulosa cell apoptosis that plays a consequential role in the loss of ovarian follicles or follicular atresia. The aim of present study was to assess malathion-induced (100 nM) reproductive stress, ultrastructural damage and changes in apoptosis frequency in ovarian granulosa cells of antral follicles. Transmission electron microscopy (TEM) was employed for ultrastructural characterization, oxidative stress was evaluated using thiobarbituric acid reactive substances (TBARS) assay to measure lipid peroxidation, and apoptosis was quantified via flow cytometry. By TEM, apoptosis was identified by the presence of an indented nuclear membrane with blebbing, pyknotic crescent-shaped fragmented nuclei, increased vacuolization, degenerating mitochondria, and lipid droplets. The results indicate a significant increase in malondialdehyde (MDA) level (nmols/g wet tissue) at a 100 nM dose of malathion i.e. 7.57±0.033*, 8.53±0.12*, and 12.87±0.78** at 4, 6, or 8 h, respectively, as compared with controls (6.07±0.033, p<0.01*, p<0.05**) showing a positive correlation between malathion-induced lipid peroxidation and percentage of granulosa cell apoptosis (r=1; p<0.01). The parallel use of these three methods enabled us to determine the role of malathion in inducing apoptosis as a consequence of cytogenetic damage and oxidative stress generated in granulosa cells of antral follicles.

In Vivo Effects of Environmental Concentrations of Produced Water on the Reproductive Function of Polar Cod (Boreogadus saida)

Offshore oil and gas drilling processes generate operational discharges such as produced water (PW), a complex mixture of seawater with polycyclic aromatic hydrocarbons (PAH) and alkylphenols (AP). Some of these compounds may interact with the endocrine system of marine organisms and alter reproductive functions. In this study, polar cod were exposed for up to 28 d to a mixture of PAH, alkylated PAH, and AP simulating the composition of North Sea PW, at low and high concentrations (1:2000 and 1:1000 dilution of the original concentrate, respectively). Potential adverse effects of PW on polar cod physiology were investigated through biomarkers of biotransformation (hepatic ethoxyresorufin O-deethylase [EROD] activity and bile PAH metabolites), endocrine disruption (plasma vitellogenin [VTG] levels and sex steroid concentrations), and gonad histology. Plasma sexual steroid levels in fish were not markedly affected by PW exposure, while higher plasma VTG concentrations were measured in females exposed to the high PW treatment for 7 and 28 d. In males exposed to the higher PW concentration, inhibition of spermatogenesis was observed after 28 d in addition to increase of melano-macrophage occurrence in testis. Females exposed to the high PW treatment for 21 d showed a significant increase of atresia incidence. Finally, a significant decrease in oocyte number was observed in high PW exposed female ovaries after 28 d of exposure.

Fecundity regulation strategy of the yellowfin tuna (Thunnus albacares) in the Western Indian Ocean

The oocyte development process and fecundity regulation (i.e. whether yellowfin tuna shows determinate or indeterminate fecundity) were analyzed to investigate the reproductive strategy of yellowfin tuna, Thunnus albacares. A total of 819 yellowfin ovaries were sampled at sea and at the Seychelles cannery during 2009 and 2010 from purse-seiners operating in the Western Indian Ocean. Histological analysis and automated computer-controlled image analysis software were used to study four main criteria applied for fecundity style determination: (a) oocyte size–frequency distribution, (b) number of cortical alveoli and total vitellogenic oocytes in different ovary maturation phases, (c) differences in mean diameter of tertiary vitellogenic oocytes, and (d) seasonal development of atresia.The results revealed an asynchronous oocyte development and a continuous oocyte size–frequency distribution throughout all ovarian developmental phases over the spawning season. The percentage and number of cortical alveoli and total vitellogenic oocytes remained constant through the spawning season. The mean diameter of tertiary vitellogenic oocytes decreased as spawning progressed. Also, the incidence of atresia was higher at the end of the spawning season as a consequence of over-recruitment of oocytes during this period. These findings revealed that yellowfin tuna exhibit indeterminate fecundity.

Oocyte development and fecundity type of the skipjack, Katsuwonus pelamis, in the Western Indian Ocean

The study aims to define the oogenesis pattern of the skipjack (Katsuwonus pelamis) of the Western Indian Ocean basin in terms of oocyte growth and recruitment style. The main objective is to define the type of fecundity regulation (i.e. determinate or indeterminate) based on four lines of evidence: (a) oocyte size-frequency distribution; (b) seasonal variation of the relative number and percentage of oocyte stages, (c) diameter of the advanced vitellogenic oocytes in females in the spawning capable phase; and (d) incidence of atresia throughout the spawning season. The samples were collected from 2009 to 2010 in the Western Indian Ocean, and 673 ovaries were classified in the different reproductive phases using histological staging. Moreover, the oocyte size distribution of 93 mature individuals was described by the newly implemented image analysis method. This species showed a broad oocyte size frequency distribution with no gap formation between the primary and secondary oocyte growth stages. There was no seasonal variation in the percentage of oocyte stages in ovaries in the spawning capable phase, and the diameter of those oocytes at the most advanced vitellogenic stage was approximately constant during the sampling period. These facts provide evidence of continuous oocyte recruitment into the standing stock of developing oocytes. Moreover, when reaching the end of the active reproductive period (i.e. February and March) the prevalence of atresia increased. This is a mechanism adopted by fishes of the indeterminate fecundity type to reabsorb the surplus oocyte production. Based on the findings, we state that the skipjack in the Western Indian Ocean shows asynchronous oocyte growth and an indeterminate fecundity type.

The Use of Hepatic and Somatic Indices and Histological Information to Characterize the Reproductive Dynamics of Atlantic SardineSardina pilchardusfrom the Portuguese Coast

AbstractSamples of Atlantic sardineSardina pilchardus(also known as European pilchard) were collected bimonthly from 2004 to 2008 off the central west coast of Portugal to describe the reproductive activity of this indeterminate batch‐spawning species; compare the seasonality of somatic growth, condition, and feeding; and evaluate differences between sexes. Monthly assessments of individual biological information for both males and females were complemented by histological analysis of ovaries during 1 year and liver tissues (both sexes) at different times of the reproductive cycle. The temporal patterns of the gonadosomatic index and various histological indices (most advanced oocyte stage, atresia incidence and prevalence, and spawning activity) indicated that Atlantic sardine were reproductively active mainly from October to March and that residual activity occurred in the remaining months. For both sexes, condition indices (hepatosomatic index, relative weight, and amount of fat stored) increased mainly during spring, reached a maximum at the end of summer just before the subsequent spawning season began, and then decreased during autumn and winter, declining to minimum levels at the beginning of spring coincident with a significant reduction in reproductive activity. Somatic growth took place mainly during spring and early summer for both sexes. The observed seasonal patterns in these biological properties suggest a seasonal transition from a period in which energy resources are allocated to reproduction (autumn and winter) to a period in which resources are allocated to growth and fat deposition (spring and summer). The only exception was the distinct hepatosomatic index pattern and the histological differences in hepatocytes between males and females during the spawning season, which may be related to the dual function of the liver in females (lipid metabolism and yolk precursor synthesis).

A Thrombospondin-Mimetic Peptide, ABT-898, Suppresses Angiogenesis and Promotes Follicular Atresia in Pre- and Early-Antral Follicles in Vivo

Using a novel in vitro angiogenesis assay, we previously showed that thrombospondin (TSP)-1 has antiangiogenic effects on rat follicles and induces apoptosis in granulosa cells in vitro. ABT-898 is an octapeptide mimetic of TSP-1 closely related to ABT-510. Here, we demonstrate the inhibitory effects of ABT-898 on follicular angiogenesis and its proapoptotic effect on granulosa cells. To investigate the potential of this peptide to inhibit follicular angiogenesis in vivo, marmoset monkeys were treated with 2.5 mg/kg ABT-898 twice daily throughout the follicular phase of the cycle. Although treatment did not block emergence of dominant follicles, angiogenesis was reduced in preantral and early-antral follicles. Furthermore, the incidence of atresia at these follicle stages was increased. To investigate whether treatment with ABT-898 would interfere with the timing or duration of the normal ovulatory rise in plasma progesterone, marmosets were treated with a depot formulation containing 25 mg ABT-898 at the start of the follicular phase, with a second injection after 2 wk. Despite active concentrations of peptide being maintained in the circulation, no apparent effects on the ovulatory cycle were observed. Taken together, these results indicate that ABT-898 is capable of having a dual effect by inhibiting follicular angiogenesis and promoting atresia of antral follicles in vivo but does not prevent ovulation or induce luteolysis, as has been observed with direct vascular endothelial growth factor inhibitors. These results suggest that ABT-898 could be a novel therapeutic to inhibit abnormal angiogenesis and induce atresia of accumulated follicles in polycystic ovary syndrome.

Liver energy, atresia and oocyte stage influence fecundity regulation in Northeast Arctic cod

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 404:173-183 (2010) - DOI: https://doi.org/10.3354/meps08486 Liver energy, atresia and oocyte stage influence fecundity regulation in Northeast Arctic cod Jon Egil Skjæraasen1,*, Richard D. M. Nash2, James Kennedy1,3, Anders Thorsen2, Trygve Nilsen4, Olav Sigurd Kjesbu2 1Department of Biology, University of Bergen, 5020 Bergen, Norway 2Institute of Marine Research, PO Box 1870 Nordnes, 5817 Bergen, Norway 3Møreforskning Ålesund, PO Box 5075, 5021 Ålesund, Norway 4Department of Mathematics, University of Bergen, 5020 Bergen, Norway *Email: jon.skjaeraasen@bio.uib.no ABSTRACT: Marine ecosystems are changing; global warming-induced increases in water temperatures and fishing have caused truncated age structures and small sizes at maturity in many stocks. This may affect both populations’ total reproductive output and the link between population demography and recruitment, yet detailed information on fecundity regulation is generally lacking for marine fishes. We therefore examined associations between liver energy, oocyte stage, leading cohort oocyte size (LC20), atresia and fecundity for the Northeast Arctic cod (NEAC) Gadus morhua L. from 2006 to 2008 in a comprehensive field and laboratory study. The relationship between the relative liver size (hepatosomatic index, HSI) and specific liver energy content was best described by an asymptotic curve, increasing rapidly at first, then levelling of at HSI > 6%. LC20 increased towards the spawning season, but was also positively associated with total length. At present there is thus a tendency towards larger NEAC females spawning earlier. The incidence of atresia was highest during the advanced yolk granule stage. Only 1% of females that reached an LC20 > 300 µm absorbed all oocytes and thereby aborted spawning. Potential fecundity showed a parabolic relationship with LC20, peaking around 614 µm, i.e. approximately on February 1st, and was positively associated with weight, liver energy and, presently, age. In summary, NEAC females that start vitellogenesis will likely spawn. Atresia and fecundity down-regulation appears only to become pronounced close to spawning. Finally, the size-dependent spawning time, which appears to have emerged in the stock recently, may alter the link between population demography and recruitment. KEY WORDS: Gadus morhua · Fecundity regulation · Atresia · Liver energy · Size-dependent spawning time Full text in pdf format PreviousNextCite this article as: Skjæraasen JE, Nash RDM, Kennedy J, Thorsen A, Nilsen T, Kjesbu OS (2010) Liver energy, atresia and oocyte stage influence fecundity regulation in Northeast Arctic cod. Mar Ecol Prog Ser 404:173-183. https://doi.org/10.3354/meps08486 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 404. Online publication date: April 08, 2010 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2010 Inter-Research.

Expression of follicle-stimulating hormone and luteinising hormone binding sites in the bitch ovary during the follicular phase

In the female dog, in contrast with most mammals, the growing follicle starts to luteinise several days before ovulation. Little is known about the physiological control of the final follicular growth in this species. In order to better understand the pituitary regulation of follicular growth, specific binding sites for FSH and LH were localised and quantified by autoradiography using [(125)I]-porcine (p) gonadotrophins on ovarian sections (7 microm) from adult Beagle bitches during the follicular phase. Follicles were analysed either before the LH surge (n = 4 bitches; n = 117 follicles) or after the LH surge and before ovulation (n = 5 bitches; n = 110 follicles). FSH binding sites were specifically and homogeneously expressed at high levels on granulosa cells of all healthy follicles from the preantral stage onwards. In contrast, LH binding sites were detected homogeneously and at high levels only on granulosa cells of follicles larger than 1 mm in diameter, including luteinised follicles. Theca binding of LH (but not FSH) was also observed, but only when using high concentrations of [(125)I]-pLH. The overall incidence of atresia was 45.8% and was dependent upon follicular diameter. Quantitative analysis of labelling showed that atretic follicles had reduced levels of both FSH and LH binding sites compared with healthy follicles. In healthy follicles, levels of both FSH and LH binding sites changed with follicle diameter. Compared with other mammals, the acquisition of LH binding on canine granulosa cells occurs in smaller sized follicles relative to the size of ovulation.

Folliculogenesis and ovarian histology of the oviparous gecko, Hemidactylus mabouia (Sauria: Gekkonidae)

Histological changes during the ovarian cycle of the oviparous gekkonid lizard, Hemidactylus mabouia are described. The ovaries each contained a single germinal epithelium (bed) with numerous oogonia and primordial follicles. Similar to other squamates, the ovarian stroma was characterized by follicles in different stages of development, and may contain corpora lutea, and corpora atretica. The seasonal study revealed that vitellogenic ovarian hypertrophy commenced in spring (September) and ovulation of the first clutch (two eggs) occurred in summer (November). A second vitellogenic cycle followed, the second clutch being ovulated in late‐summer (January). Ovarian quiescence, marked by predominance of pre‐vitellogenic (hydration stage) follicles, was evident in females collected from February to July. Although oocyte growth was accompanied by changes in the granulosa layer, zona radiata and thecal layers, the zona pellucida remained unchanged throughout. The small cells of the granulosa layer differentiated into three distinct cell types ‐ small, intermediate and the conspicuous large pyriform cells. Similar to most other squamates, the intermediate and pyriform cells at the onset of vitellogenesis regressed to a single cuboidal epithelium. Following ovulation, the granulosa layer hypertrophied forming luteal tissue. The theca layer differentiated into two layers and septal invasion of the corpus luteum took place. At the time of oviposition, corpora lutea regressed to form ovarian scars (corpora albicantia). Follicular artresia occurred in previtellogenic follicles (hydration stage) and seldom in vitellogenic follicles. The highest incidence of atresia occurred in the post‐breeding period (February). The gross morphology, oogenesis and folliculogenesis of the ovaries of H. mabouia correspond to the general squamate pattern described for oviparous reptiles.