scholarly journals Diet and food consumption of the pearl cichlid Geophagus brasiliensis (Teleostei: Cichlidae): relationships with gender and sexual maturity

2011 ◽  
Vol 9 (4) ◽  
pp. 825-830 ◽  
Author(s):  
Rodrigo F. Bastos ◽  
Mário V. Condini ◽  
Antonio S. Varela Junior ◽  
Alexandre M. Garcia
Keyword(s):  
Food Consumption ◽  
Vascular Plants ◽  
Sexual Maturity ◽  
Wide Distribution ◽  
Mean Values ◽  
Secondary Sexual Characteristics ◽  
Geophagus Brasiliensis ◽  
Sexual Characteristics ◽  
Gender Based ◽  
Fish Trade

Despite the importance of the pearl cichlid Geophagus brasiliensis for the aquarium fish trade worldwide and its wide distribution, many aspects of its biology, such as the relationships between its feeding ecology and reproductive behavior, are not fully understood in natural conditions on its native habitat. In this paper, we investigated its diet focusing on how differences in diet and food consumption are related to differences in gender and sexual maturity. The digestive tract of each individual was dissected and had its content analyzed, whereas each gonad was microscopically analyzed to determine gender (male/female) and sexual maturity (immature/mature). A total of 28 females and 31 males were analyzed. Mature individuals were more common than immature specimens both for males (64.50%) and females (64.30%). The analysis of 52 individuals with non-empty digestive tracts revealed a diet comprised of 27 items. According to the Index of Alimentary importance (%IAi), the most important food items in the diet were Gastropoda (37.30%), fragments of vascular plants (15.16%), detritus (10.14%), Amphipoda (9.24%), and fish scales (6.29%). Mature males had more empty stomachs (65.00%) when compared to immature males (27.27%) and immature (55.56%) and mature females (40.00%). Also, mature females seemed to have more food consumption (greater mean values of total volume) in their digestive tracts than mature males. Some hypotheses are proposed in order to distinguish if this gender-based difference in food consumption in mature individuals of the pearl cichlid could be associated with the development of primary and secondary sexual characteristics or with asymmetrical time invested in parental care activities.

scholarly journals Growth patterns in brooding dinosaurs reveals the timing of sexual maturity in non-avian dinosaurs and genesis of the avian condition

2007 ◽  
Vol 3 (5) ◽  
pp. 558-561 ◽  
Author(s):  
Gregory M Erickson ◽  
Kristina Curry Rogers ◽  
David J Varricchio ◽  
Mark A Norell ◽  
Xing Xu
Keyword(s):  
Sexual Maturation ◽  
Sexual Maturity ◽  
Reproductive Activity ◽  
Growth Patterns ◽  
The Other ◽  
Growth Line ◽  
Adult Size ◽  
Secondary Sexual Characteristics ◽  
Sexual Characteristics ◽  
Population Sizes

The timing of sexual maturation in non-avian dinosaurs is not known. In extant squamates and crocodilians it occurs in conjunction with the initial slowing of growth rates as adult size is approached. In birds (living dinosaurs) on the other hand, reproductive activity begins well after somatic maturity. Here we used growth line counts and spacing in all of the known brooding non-avian dinosaurs to determine the stages of development when they perished. It was revealed that sexual maturation occurred well before full adult size was reached—the primitive reptilian condition. In this sense, the life history and physiology of non-avian dinosaurs was not like that of modern birds. Palaeobiological ramifications of these findings include the potential to deduce reproductive lifespan, fecundity and reproductive population sizes in non-avian dinosaurs, as well as aid in the identification of secondary sexual characteristics.

scholarly journals Obesity accelerates secondary sexual maturity in girls

2012 ◽  
Vol 52 (4) ◽  
pp. 213
Author(s):  
Meirina Sari ◽  
Endy Paryanto Prawirohartono ◽  
Madarina Julia
Keyword(s):  
Health Effects ◽  
Sexual Maturation ◽  
Sexual Maturity ◽  
Tanner Stage ◽  
Pubic Hair ◽  
Stage Ii ◽  
Secondary Sexual Characteristics ◽  
Hazard Ratios ◽  
Sexual Characteristics ◽  
Secondary Sexual

Background Worldwide incidence of obesity in children isincreasing. Obesity may have many health effects includingadvancement of sexual maturity.Objective T he aim of this study was to assess the timing ofsecondary sexual maturation in obese vs. non􀁄obese girls.Methods Subjects were 105 obese and 105 non􀁄obese girls, aged7 to 8 years who had not entered puberty. Breast and pubic hairgrowth, secondary sexual characteristics, were assessed at baselineand every 4 months for two years. Onset of puberty was defined asTanner stage for secondary sexual maturation of 2: breast Tannerstage II (B2) and/or 2: pubic hair Tanner stage II (P2). Survivalanalyses were used to estimate time to puberty in both groups.Cox regressions were used to analyze possible factors affectingsecondary sexual maturation.Results Mean onset of breast budding (B2) was 7.8 (95% CI 7.7to 7.8) years in obese girls vs. 8.6 (95% CI 8.5 to 8.6) years innon􀁄obese girls (P<O.OOl). Mean onset of pub arc he (P2) was 8.7(95% CI 8.6 to 8.8) years in obese girls vs. 9.0 (95% CI 8.9 to 9.0)years in non􀁄obese girls (P<O.OOl). Hazard ratios of obese girlsto experience an earlier secondary sexual maturation at maturitylevel B2, B3 and P2 were 1.34 (95% CI 1.19 to 1.52), 6.91 (95%CI 3.90 to 12.24) and 3.78 (95% CI 2.42 to 5.89), respectively.Conclusions Obesity was associated with earlier onset ofpuberty in girls. Obese girls entered puberty approximately 3 to9 months earlier than their non􀁄obese peers. [Paediatr Indones.2012;52:213-8].

Sex determination and Y chromosome constitutive heterochromatin

2019 ◽  
Vol 1 (1) ◽  
pp. 1-5
Author(s):  
Abyt Ibraimov
Keyword(s):  
Sex Determination ◽  
Y Chromosome ◽  
Constitutive Heterochromatin ◽  
Sex Differentiation ◽  
Secondary Sexual Characteristics ◽  
Biological Meaning ◽  
Heterochromatin Block ◽  
Sexual Characteristics ◽  
Open Question ◽  
Efficient Elimination

In many animals, including us, the genetic sex is determined at fertilization by sex chromosomes. Seemingly, the sex determination (SD) in human and animals is determined by the amount of constitutive heterochromatin on Y chromosome via cell thermoregulation. It is assumed the medulla and cortex tissue cells in the undifferentiated embryonic gonads (UEG) differ in vulnerability to the increase of the intracellular temperature. If the amount of the Y chromosome constitutive heterochromatin is enough for efficient elimination of heat difference between the nucleus and cytoplasm in rapidly growing UEG cells the medulla tissue survives. Otherwise it doomed to degeneration and a cortex tissue will remain in the UEG. Regardless of whether our assumption is true or not, it remains an open question why on Y chromosome there is a large constitutive heterochromatin block? What is its biological meaning? Does it relate to sex determination, sex differentiation and development of secondary sexual characteristics? If so, what is its mechanism: chemical or physical? There is no scientifically sound answer to these questions.

Reproductive failure of the red shiner (Cyprinella lutrensis) after exposure to an exogenous estrogen

2010 ◽  
Vol 67 (11) ◽  
pp. 1730-1743 ◽  
Author(s):  
Michelle M. McGree ◽  
Dana L. Winkelman ◽  
Nicole  K.M.  Vieira ◽  
Alan  M.  Vajda
Keyword(s):  
Reproductive Success ◽  
Great Plains ◽  
Endocrine Disrupting Chemicals ◽  
Water Control ◽  
Secondary Sexual Characteristics ◽  
Cyprinella Lutrensis ◽  
The Us ◽  
Sexual Characteristics ◽  
Solvent Control ◽  
17Β Estradiol

Endocrine disrupting chemicals (EDCs) have been detected in surface waters worldwide and can lead to developmental and reproductive disruption in exposed fishes. In the US Great Plains, EDCs are impacting streams and rivers and may be causing adverse reproductive effects. To examine how estrogenic EDCs might affect reproductive success of plains fishes, we experimentally exposed male red shiners ( Cyprinella lutrensis ) to exogenous 17β-estradiol. We characterized the effects of estradiol on male gonadal histology and secondary sexual characteristics, determined whether exposure reduced reproductive success, and examined the effects of depuration. Adults were exposed to a mean concentration of 70 ng·L−1 estradiol, a solvent control, or a water control for at least 83 days. Male exposure to estradiol resulted in elevated plasma vitellogenin concentrations, changes in spermatogenesis, reduced mating coloration and tubercles, altered mating behaviors, and reduced reproductive success with no viable progeny produced. Reproductive endpoints improved upon depuration (28 days). Exposure to estradiol had significant adverse effects on red shiners, indicating that wild populations may face developmental and reproductive difficulties if they are chronically exposed to estradiol.

Comparative urogenital morphology and external sex determination in muskellunge, Esox masquinongy Mitchill

1989 ◽  
Vol 67 (4) ◽  
pp. 1053-1060 ◽  
Author(s):  
Bernard Lebeau ◽  
Gérard Pageau
Keyword(s):  
Ventral Surface ◽  
Northern Pike ◽  
Structural Basis ◽  
Simple Method ◽  
Esox Masquinongy ◽  
Secondary Sexual Characteristics ◽  
Sexual Characteristics ◽  
Spawning Behaviour ◽  
Accurate Indicator ◽  
Secondary Sexual

Primary and secondary sexual characteristics in northern pike, Esox lucius Linneaus, and muskellunge, Esox masquinongy Mitchill, differ markedly. Differences in the internal urogenital anatomy include the structure of the genital ducts and the angle they form with the ventral surface. Externally, the genital and urinary ducts open directly to the environment in northern pike, whereas in muskellunge they open into a muscular papilla and then through a urogenital pore. Differences in sexual dimorphism between the two closely related esocids constitute a structural basis to explain the known differences in spawning behaviour and reproductive success. Differences in secondary sexual characteristics explain why the methods developed by Demchenko or Casselman to externally sex pike are inapplicable to muskellunge. To develop and test two external sexing techniques for muskellunge, specimens were collected from two regions in Canada from 1980 to 1987. Examination of reproductive products obtained from stripping provided an accurate indicator of sex and sexual maturity, but demonstrated serious limitations. A simple method to sex muskellunge by examination of the external urogenital morphology is described for juveniles and adults. Dissection of fish revealed that with the urogenital examination technique we sexed juveniles with a success rate of 92–98%, and adults with 100% accuracy.

REPLACEMENT ORAL ETHINYLOESTRADIOL THERAPY FOR GONADAL DYSGENESIS: GROWTH AND ADRENAL ANDROGEN STUDIES

1979 ◽  
Vol 91 (3) ◽  
pp. 519-528 ◽  
Author(s):  
Anne W. Lucky ◽  
Samuel P. Marynick ◽  
Robert W. Rebar ◽  
Gordon B. Cutler ◽  
Michael Glen ◽  
...  
Keyword(s):  
Gonadal Dysgenesis ◽  
Bone Age ◽  
Pubic Hair ◽  
Height Velocity ◽  
First Year ◽  
Adrenal Androgen ◽  
Secondary Sexual Characteristics ◽  
Sexual Characteristics ◽  
Second Year ◽  
Pre Treatment

ABSTRACT We have studied growth and adrenal dehydroepiandrosterone (DHA) responses to iv synthetic adrenocorticotrophic hormone (ACTH, Cortrosyn) in 6 girls with gonadal dysgenesis before and during treatment with lowdose ethinyloestradiol (EOe2). In all patients there was a statisfactory induction of secondary sexual characteristics including increase in breasts and pubic hair and onset of withdrawal bleeding within 6 months of therapy. Height velocity increased from 2.8 ± 0.9 cm/year pre-treatment to 5.3 ± 1.5 cm/year (P < 0.02) in the first year. There was deceleration to 1.9 ± 1.1 cm/year in the second year. There was no disproportionate advancement in bone age and thus, presumably, no loss of ultimate height. We could demonstrate no change in basal or ACTH-stimulated levels of DHA, a specific adrenal androgen, to account for the increased pubic hair and growth in these patients.

The effects of phthalate and nonylphenol exposure on body size and secondary sexual characteristics during puberty

2015 ◽  
Vol 218 (7) ◽  
pp. 603-615 ◽  
Author(s):  
Jia-Woei Hou ◽  
Ching-Ling Lin ◽  
Yen-An Tsai ◽  
Chia-Huang Chang ◽  
Kai-Wei Liao ◽  
...  
Keyword(s):  
Body Size ◽  
Secondary Sexual Characteristics ◽  
Sexual Characteristics ◽  
Secondary Sexual

scholarly journals Somatotypical features of the age dynamics of secondary sexual characteristics and functional parameters in city schoolchildren

2021 ◽  
pp. 113-118
Author(s):  
V. A. Melnik
Keyword(s):  
Blood Pressure ◽  
Body Type ◽  
Age Dynamics ◽  
Functional Parameters ◽  
Secondary Sexual Characteristics ◽  
Age Related ◽  
Sexual Characteristics ◽  
Age Range ◽  
Age Related Changes ◽  
Secondary Sexual

Objective: to assess the constitutional features of the age dynamics of secondary sexual characteristics and functional parameters of city schoolchildren in the age range of 7–17 years.Materials and methods. The objects of the study were schoolchildren aged 7–17. The stages of the expression of secondary sexual characteristics were determined visually according to the scheme by J.M. Tanner. The functional parameters of the examined schoolchildren were assessed using the methods of dynamometry, spirometry; blood pressure and heart rates, as well as the time of simple sensorimotor reactions were measured.Results. As a result of the performed studies, it has been found that representatives of the hypersomnic types are ahead of other types to reveal the first stages of secondary sexual characteristics. Schoolchildren with the leptosomic morphotypes due to higher rates of their development have reached the definitive stages by the same age as those with the hypersomnic variants. The intensity of age-related changes in functional parameters (strength qualities, circulatory and respiratory systems, nervous system) in the studied objects depends on their body type.Conclusion. The stage and rate of puberty, as well as the development of functional parameters in city schoolchildren depends on their somatotype.

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