Background: Fecundity is an important parameter in fisheries that predicts the reproductive capability of fish stock. Information on the fecundity of Common carp is helpful in estimating the amount ...of offspring produced in spawning season, which is essential for the stock assessment of the species. Assessment of the fecundity of a fish is essential for evaluating the commercial potentialities of its stock, life history, practical culture and actual management of the fishery. Common carp is a commercially important fish which has the potential to meet the demand of food in the country. Scanty of data is available on fecundity parameter of common carp in Kashmir waters. Therefore, this research work aims to estimate the fecundity of Common carp collected from the Dal lake of Kashmir.
Methods: The present study aims to estimate the fecundity of Common carp, Cyprinus carpio var. communis existing in Dal Lake, Kashmir. The 30 fish samples were collected once every month from the month of January 2018 to December 2018. Fishes were brought to Fisheries Resource Management (FRM), Faculty of Fisheries, SKUAST-K Laboratory for the estimation of total length, weight of fishes and weight of ovaries. Gravimetric and actual counting method was used for the estimation of fecundity. Result: It was observed that the number of eggs varied from 16650 (for a fish with total length 180mm and total weight 120 g) to 129000 (for a fish with total length 430 mm and total weight 1300 g. The mean absolute fecundity was recorded as 68864.07± 6563.59 for a fish with a mean total length of 301.43 ± 13.93 mm and mean total weight of 435.1 ± 66.51 g. The relative fecundity ranged from 99.2-240.8 and the mean relative fecundity was 185.96. Significant positive correlation was found between fish weight and absolute fecundity. (r= 0.907, p less than 0.01), fish length and absolute fecundity (r= 0.976, p less than 0.01), Ovary weight and absolute fecundity (r= 0.998, p less than 0.01). Relative fecundity showed a significant negative correlation with weight, length and absolute fecundity (r= -0.747, p less than 0.01; r= -0.419, p less than 0.05 and r= -0.460, p less than 0.05 respectively.
QUESTIONS: Is there any evidence of coordination among leaf, stem and root traits, and thereby of the existence of a plant economics spectrum at the species and community level in Mediterranean ...forests? Are these traits related to plant size and seed mass? LOCATION: Mediterranean forests and shrublands, Sierra Morena mountains, Córdoba, southern Spain. METHODS: We selected nine woody plant communities along a natural local gradient of soil water and nutrient availability. We measured key leaf, stem, root and whole‐plant traits for 38 dominant woody plant species. The variation across species of 15 functional traits (of the leaf, stem and root) was analysed and coordination among them was tested. We explored the relationships between these traits (hereafter ‘resource‐use traits’ due to their close association with the acquisition–conservation trade‐off) and plant height and seed mass. Finally, we compared results at species level with those calculated at community level, considering community‐weighted means (CWMs). RESULTS: We found a significant coordination between traits belonging to different plant organs, and propose the existence of a plant economics spectrum in Mediterranean forests along the environmental gradient. However, weaker relationships were found within groups of species under similar environmental conditions. We did not find the expected orthogonal relationships between plant height, seed mass and resource‐use traits. Relationships among functional traits were stronger at the community level than at the species level. CONCLUSIONS: This study reveals a high degree of functional coordination between traits belonging to different plant organs at both species and community level, and suggests the existence of a plant economics spectrum across 38 Mediterranean woody plant species. However, this general trend of functional coordination between organs became weaker or disappeared when considering restricted groups of species belonging to environmentally similar sites (e.g. dry vs wet sites), suggesting that the diversification of strategies within communities is not related to the economics spectrum at a lower spatial scale. Interestingly, the high degree of coordination between resource‐use traits and seed mass at the community level seems to support the tolerance–fecundity model, which predicts an inverse relationship between fecundity and stress tolerance.
Polymesoda arctata is a Caribbean estuarine clam commercially important that currently is considered threatened. The reproductive conditioning, spawning and early development were evaluated under ...laboratory conditions using organisms collected in the lagoon system of Ciénaga Grande de Santa Marta (Colombian Caribbean) between December 2020 and May 2021. Two reproductive conditioning experiments were conducted over 7 weeks, examining the frequency of mature animals in the natural environment (controls) and in the laboratory under two water temperatures (26 and 29 °C) and different salinity regimes (constant at 5 and 15 ppt, increasing from 5 to 15 ppt, and decreasing from 15 to 5 ppt). One spawning experiment was done, comparing the spawning response of adult clams exposed to various stimuli (changes in water temperature and salinity, flow of seawater irradiated with UV light, addition of a high concentration of food and sperm to the water, as well as injections of serotonin and KCl into the foot and/or adductor muscle). Higher frequencies of mature clams were observed after 2 to 5 weeks of reproductive conditioning at a low temperature (26 °C) and under a constant salinity regime (at 5 or 15 ppt). Higher percentages of spawning and post-stimulation survival as well as spawning response speed were observed in specimens injected in the foot with a low concentration of serotonin (0.4 mL at 20 μM). The time of spawning response onset was shorter in males than in females. The fecundity increased with the live weight of the females, showing an average value of 3.4 × 106 oocytes per female. The early development of the estuarine clam from oocyte to juvenile stage was described in detail. The growth rates of larvae and spat were relatively high but their survival values were low, showing the need for additional research on the larval and post-larval rearing.
•First report on the juvenile hatchery-production of the estuarine clam, P. arctata.•Reproductive conditioning of P. arctata improves its gonadal maturity.•Pedal-injection of serotonin induces the spawning of P. arctata.•Growth rates of spat were higher than larvae, but its survival values were lower.
To study the association between AMH and time to pregnancy. While it has been hypothesized that serum anti-Müllerian hormone (AMH) levels may indicate the chance of conception, findings have been ...mixed. Given that any association is expected to be modest, and it is possible that previous studies have been underpowered, we investigated this relationship in the largest prospective cohort to date.
Prospective time-to-pregnancy cohort study.
3,150 US women who had been trying to conceive for less than 3 months and had purchased a Modern Fertility Hormone Test.
We developed a discrete time-to-event model utilizing a binomial complementary log-log error structure within a generalized additive modeling framework, adjusting for confounding factors such as age, BMI, parity, smoking status, PCOS, and others. Sensitivity analyses were performed in women with regular menstrual cycles (21-35 days), who did not report using fertility treatments, using alternate AMH categories (<0.7, 0.7-8.5, >8.5 ng/mL), and AMH as a continuous measure.
Primary outcomes included cumulative conception probability within 12 cycles and relative fecundability per menstrual cycle. Conception was defined by a self-reported positive pregnancy test.
Participants contributed 7.21 ± 5.32 cycles, with 1,325 (42.1%) achieving a pregnancy. Women with low AMH (<1ng/mL, n=427) had a lower chance of natural conception (Adjusted Hazard Ratio (adjHR 0.77, 95%CI 0.64, 0.94, p=0.009) compared to women with a normal AMH (1 - 5.5ng/mL). There was no difference between high (5.5+ ng/ml) and normal AMH categories (adjHR 1.11, 95% CI 0.94, 1.31, p=0.2). The inclusion of AMH improved the model (net reclassification index 0.10 0.06 - 0.14); P<0.001). The instantaneous probability of conception was highest in cycle 4 across all AMH categories: the probability of natural conception was 11.2% (95% CI 9.0, 14.0) for low AMH, 14.3% (95% CI 12.3, 16.5) for normal AMH, and 15.7% (95%CI 12.9, 19.0) for high AMH. In the regular cycles sensitivity analysis (n=1,791), the low AMH group had a lower chance of conception (adjHR 0.77 95% CI 0.61, 0.97, p = 0.028) in the low AMH group compared to normal AMH, and similarly in the continuous model (adjHR 0.90; 95% CI 0.85-0.95, p<0.0001).
Low AMH levels (<1 ng/ml) are independently associated with a modest but significant reduction in the chance of conception.
Multiple niche‐based processes including conspecific negative density dependence (CNDD) determine plant regeneration and community structure. We ask how interspecific and intraspecific ...density‐dependent interactions relate to plant life histories and associated functional traits. Using hierarchical models, we analysed how such interactions affected first‐year survival of seedling recruits of 175 species in a tropical forest, and how species abundances and functional traits are related to interspecific variation in density‐dependent effects. Conspecific seedling neighbour effects prevailed over the effects of larger conspecific and all heterospecific neighbours. Tolerance of seedling CNDD enhanced recruit survival and subsequent abundance, all of which were greater among larger seeded, slow‐growing and well‐defended species. Niche differentiation along the growth–survival trade‐off and tolerance of seedling CNDD strongly correlated with regeneration success, with manifest consequences for community structure. The ability of larger seeded species to better tolerate CNDD suggests a novel mechanism for CNDD to contribute to seed‐size variation and promote species coexistence through a tolerance–fecundity trade‐off.
Cuticular proteins, in conjunction with chitin, compose the insect exoskeleton, and play a key role in the growth, development, and molting of insects. However, the specific functions of most ...cuticular protein genes in the growth, development, and reproductive processes of the pea aphid (Acyrthosiphon pisum) remain unclear. In this study, we have identified six cuticular protein genes in the pea aphid, namely ApCP7, ApCP10, ApCP19, ApCP19.8-like, ApCP35 and ApCP62. We found that the expression levels of six genes were highly expressed during the adult stage, and except for ApCP10, which is highly expressed in the pea aphid cuticle, other genes were highly expressed in the ovaries. Subsequently, we observed that the survival rate and fecundity of pea aphid were significantly lower than those of the control group after silencing ApCP7 and ApCP62 through RNA interference. Furthermore, when ApCP7 transcript levels were reduced, aphid encountered difficulties in molting, were smaller in body size, and exhibited a darker body color. These results indicate that ApCP7 and ApCP62 are involved in the development and reproduction of pea aphid, and could be used as RNAi targets for controlling pea aphid.
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This paper mainly aims at highlighting the differences in reproductive parameters of females of a lot of Palas Merino breed crossed with the Merino Palas breed male (group I) and a lot of Palas ...Merino females crossed with males of breed Ile de France (group II). Research has been conducted in a trading company in Vaslui county, on a herd of 600 female heads. The results showed that reproductive parameters of Merino sheep breed group crossed with rams of the breed Ile de France (group II) where higher compared to the Merino sheep breed group crossed with Merino rams (group I), given that environmental conditions were identical for two lots. So, the index of fecundity determinate had value of 92.00 %from the first batch of sheep and of 92.33 % for the second batch of sheep also The calculated prolificacy for the these two lots had values of 113.40 for the first lot and of 136.69% for the second lot. Note that two reproductive parameters analyzed a very significant difference was found in the prolificacy parameter. Of breeding parameters studied, a very significant difference was found in the prolificacy parameter.
Abstract
STUDY QUESTION
Does the long-term fecundity of women with polycystic ovary syndrome (PCOS) differ from those without PCOS?
SUMMARY ANSWER
Cumulative probability of childbirth is similar ...between women with and without PCOS.
WHAT IS KNOWN ALREADY
PCOS is the main cause of anovulatory infertility in women after menarche. Previous studies indirectly suggest that fecundity in women with PCOS over the longer term may not be lower than in women without PCOS.
STUDY DESIGN, SIZE, DURATION
This is a population-based study using four linked Swedish national registries. A total of 45 395 women with PCOS and 217 049 non-PCOS women were included. Follow-up began at the age of 18 years and continued for a maximum of 26 years, from 1989 to the end of 2015. Childbirth was the main outcome, as identified from the Medical Birth Register.
PARTICIPANTS/MATERIALS, SETTING, METHODS
All women born between 1971 and 1997 who were identified with a PCOS diagnosis in the Swedish Patient Registry between 1 January 2001 and 31 December 2016 were included in the study population. Five controls per women with PCOS were randomly drawn from the Total Population Registry. The control women were born in the same year and living in the same municipality as the patient. The fecundity ratio (FR) was calculated by clustered Cox regression using a robust variance, adjusted for maternal birth period, country of birth and level of education.
MAIN RESULTS AND THE ROLE OF CHANCE
The cumulative probability of childbirth was 80.2% (95% CI, 79.5–80.9%) in women with PCOS and 78.2% (95% CI, 77.9–78.5%) in those without PCOS. Adjusted FR was 0.81 (95% CI, 0.80–0.82) for first childbirth and 0.58 (95% CI, 0.57–0.60) for first childbirth following a spontaneous pregnancy. The FR for second childbirth was 0.79 (95% CI, 0.77–0.80). Women with PCOS had more than one child less frequently than the comparison group. Within the PCOS group, early age at diagnosis, later birth year, Nordic country of origin and low educational level positively influenced the FR.
LIMITATIONS, REASONS FOR CAUTION
Results are not adjusted for BMI, and time from intention to conceive to first childbirth could not be captured. Data on pregnancies, miscarriages or abortions and fertility treatment are unknown for women who did not give birth during the study period. Women with PCOS who did not seek medical assistance might have been incorrectly classified as not having the disease. Such misclassification would lead to an underestimation of the true association between PCOS and outcomes.
WIDER IMPLICATIONS OF THE FINDINGS
While cumulative probability of childbirth is similar between groups, women with PCOS need longer time to achieve their first childbirth. Women with PCOS have a lower FR and give birth to fewer children per woman than women without PCOS. Early diagnosis of and information about PCOS may improve affected women’s reproductive potential.
STUDY FUNDING/COMPETING INTEREST(S)
This study was funded by the Swedish Society of Medicine. Inger Sundström Poromaa has, over the past 3 years, received compensation as a consultant and lecturer for Bayer Schering Pharma, MSD, Gedeon Richter, Peptonics and Lundbeck A/S. The other authors declare no competing interests.
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