Photomanipulation of sexual maturation and breeding cycle of the steppe polecat (Mustela eversmanni) and other techniques for more rapid propagation of the species

1990 ◽  
Vol 255 (2) ◽  
pp. 232-238 ◽  
Author(s):  
Rodney A. Mead ◽  
Sandra Neirinckx
2017 ◽  
Vol 11 (2) ◽  
pp. 53 ◽  
Author(s):  
Anang Hari Kristanto ◽  
Jacques Slembrouck ◽  
Marc Legendre

The age and weight at first sexual maturation and the seasonal variatrons of sexual maturity of pangasius hypohthalmus were determined on a fish group spawned in April 1997 and followed up until 32 months of  age at the sukamandi RIFF station, west Java Indonesia.


Author(s):  
Daryl A. Cornish ◽  
George L. Smit

Oreochromis mossambicus is currently receiving much attention as a candidater species for aquaculture programs within Southern Africa. This has stimulated interest in its breeding cycle as well as the morphological characteristics of the gonads. Limited information is available on SEM and TEM observations of the male gonads. It is known that the testis of O. mossambicus is a paired, intra-abdominal structure of the lobular type, although further details of its characteristics are not known. Current investigations have shown that spermatids reach full maturity some two months after the female becomes gravid. Throughout the year, the testes contain spermatids at various stages of development although spermiogenesis appears to be maximal during November when spawning occurs. This paper describes the morphological and ultrastructural characteristics of the testes and spermatids.Specimens of this fish were collected at Syferkuil Dam, 8 km north- west of the University of the North over a twelve month period, sacrificed and the testes excised.


MedPharmRes ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 33-37
Author(s):  
Tam M. Do ◽  
Thanh K. Van ◽  
Huyen TT. Bich ◽  
Thanh TK. Tran ◽  
Minh X. Ngo ◽  
...  

Background: Puberty is a milestone in child and adolescent development, yet a feasible tool to accurately assess pubertal stage in community context has not been validated in Vietnam. Aim: This study was conducted to validate pubertal self-report among Ho Chi Minh City children and adolescents in comparison with paediatrician’s assessment. Methods: 80 girls and 76 boys aged from 6 to 17 years old from 5 schools in Ho Chi Minh City were recruited. Self-administered questionnaires about sexual maturation were distributed to participants and results were compared with physician’s pubertal examination. Kappa statistic and Kendall’s τ b were used to evaluate validity of the questionnaire. Results: Boys tended to overestimate their development stages while girls tended to underestimate. Fair to almost perfect agreement between students’ reports and paediatricians’ evaluation, along with high concordance was recorded, however younger boys (aged 6-11) showed limited evaluation of their own sexual maturation. Conclusion: This method was inaccurate to evaluate younger boys’ sexual maturation; however, acceptable accuracy in sexual maturation estimation among younger girls and adolescents could allow it to serve as an effective screening tool in community context.


2009 ◽  
Vol 0 (0) ◽  
Author(s):  
Jenner C. V. Azevedo ◽  
Lana M. P. Brasil ◽  
Taísa B. M. A. Macedo ◽  
Lúcia F. C. Pedrosa ◽  
Ricardo F. Arrais

Author(s):  
Elizabeth K. Reynolds ◽  
Linda C. Mayes

Adolescence is the time between the beginning of sexual maturation and adulthood, typically bounded by the ages of 13 to 19 years. One construct that holds a central place in many theories of development and psychopathology is impulsivity. Impulsivity has been considered to play an important role in normal behavior as well as linked to several problematic behaviors that are present or arise during adolescence. Impulsivity, considered to be a multidimensional construct, has been defined and measured in a variety of ways. This chapter will discuss the definitions of impulsivity, measurement (including self-report and behavioral tasks), developmental course, behaviors and disorders in which it is implicated, and future directions.


Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 419
Author(s):  
Valeria Calcaterra ◽  
Hellas Cena ◽  
Corrado Regalbuto ◽  
Federica Vinci ◽  
Debora Porri ◽  
...  

Puberty is a crucial developmental stage in the life span, necessary to achieve reproductive and somatic maturity. Timing of puberty is modulated by and responds to central neurotransmitters, hormones, and environmental factors leading to hypothalamic-pituitary-gonadal axis maturation. The connection between hormones and nutrition during critical periods of growth, like fetal life or infancy, is fundamental for metabolic adaptation response and pubertal development control and prediction. Since birth weight is an important indicator of growth estimation during fetal life, restricted prenatal growth, such as intrauterine growth restriction (IUGR) and small for gestational age (SGA), may impact endocrine system, affecting pubertal development. Successively, lactation along with early life optimal nutrition during infancy and childhood may be important in order to set up timing of sexual maturation and provide successful reproduction at a later time. Sexual maturation and healthy growth are also influenced by nutrition requirements and diet composition. Early nutritional surveillance and monitoring of pubertal development is recommended in all children, particularly in those at risk, such as the ones born SGA and/or IUGR, as well as in the case of sudden weight gain during infancy. Adequate macro and micronutrient intake is essential for healthy growth and sexual maturity.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adriano dos Santos ◽  
Erina Vitório Rodrigues ◽  
Bruno Galvêas Laviola ◽  
Larissa Pereira Ribeiro Teodoro ◽  
Paulo Eduardo Teodoro ◽  
...  

AbstractGenome-wide selection (GWS) has been becoming an essential tool in the genetic breeding of long-life species, as it increases the gain per time unit. This study had a hypothesis that GWS is a tool that can decrease the breeding cycle in Jatropha. Our objective was to compare GWS with phenotypic selection in terms of accuracy and efficiency over three harvests. Models were developed throughout the harvests to evaluate their applicability in predicting genetic values in later harvests. For this purpose, 386 individuals of the breeding population obtained from crossings between 42 parents were evaluated. The population was evaluated in random block design, with six replicates over three harvests. The genetic effects of markers were predicted in the population using 811 SNP's markers with call rate = 95% and minor allele frequency (MAF) > 4%. GWS enables gains of 108 to 346% over the phenotypic selection, with a 50% reduction in the selection cycle. This technique has potential for the Jatropha breeding since it allows the accurate obtaining of GEBV and higher efficiency compared to the phenotypic selection by reducing the time necessary to complete the selection cycle. In order to apply GWS in the first harvests, a large number of individuals in the breeding population are needed. In the case of few individuals in the population, it is recommended to perform a larger number of harvests.


Sign in / Sign up

Export Citation Format

Share Document