Seasonal variation in the profile of sex steroids and histological testicular development of brook trout (Salvelinus fontinalis Mitchill) during the annual reproductive cycle in Tasmania

2017 ◽  
Vol 65 (5) ◽  
pp. 313 ◽  
Author(s):  
Shafaq Fatima ◽  
Mark Adams ◽  
Ryan Wilkinson
Keyword(s):  
Reproductive Cycle ◽  
Sex Steroids ◽  
Brook Trout ◽  
Gonadosomatic Index ◽  
Mean Value ◽  
Testicular Development ◽  
Ambient Light ◽  
Annual Reproductive Cycle ◽  
Early Maturation ◽  
Second Year

Early maturation in brook trout males has been a constraint for commercial production of this species in Tasmania. However, control of maturation in males can be achieved by manipulating photoperiod (duration of light phase). To design an appropriate light treatment regime, an assessment of the annual reproductive cycle was initially required under ambient photoperiod as the annual reproductive cycle of male brook trout under ambient Tasmanian conditions of light and temperature was unknown. Here we describe the seasonal variations in testicular development and plasma profiles of testosterone (T), 11-ketotestosterone (11-KT) and oestradiol-17β (E2) during the second year in a male brook trout cohort held under ambient light conditions. Brook trout males were recruited for maturation in December when a reduction in daylength presumably stimulated testicular development. Increases in levels of T, 11-KT and gonadosomatic index (GSI) values were observed soon after the summer solstice, corresponding with maturation. The highest GSI mean value (3.44 ± 0.11%) was observed in April when mature males could be manually stripped of milt and such males were present until July. Profiles of sex steroids and histological development observed in this study were finely synchronised with variations in seasonal photoperiod changes. Photoperiod before recruitment during December should be controlled to manipulate maturation in brook trout males during their second year.

Monthly variations in the profile of sex steroids and ovarian development of brook trout (Salvelinus fontinalis Mitchill) during the annual reproductive cycle in Tasmania

2015 ◽  
Vol 63 (3) ◽  
pp. 220 ◽  
Author(s):  
Shafaq Fatima ◽  
Mark Adams ◽  
Ryan Wilkinson
Keyword(s):  
Reproductive Cycle ◽  
Sex Steroids ◽  
Brook Trout ◽  
Ovarian Development ◽  
Gonadosomatic Index ◽  
Annual Reproductive Cycle ◽  
Total Fecundity ◽  
Mature Fish ◽  
Index Value ◽  
Monthly Variations

Control of maturation in all-female salmonid stock can be achieved by manipulating photoperiod. This initially requires an assessment of the annual reproductive cycle under ambient photoperiod. This study therefore describes the seasonal variations in ovarian development and plasma profiles of oestradiol-17β and testosterone during the second year of a population of female brook trout. It was found that fish recruited for maturation following the summer solstice in December. Shortening of photoperiod likely stimulated the brain–pituitary–gonadal axis for vigorous progress of ovarian development, as indicated by increasing levels of oestradiol-17β and gonadosomatic index values. The highest gonadosomatic index value (18.26 ± 1.1%) was observed in June. During July, eggs were released from mature females by manual stripping. Total fecundity was observed as 4266 ± 341 oocytes per mature fish. Profiles of sex steroids observed here were found to be finely entrained within the succession of seasonal photoperiod. This finding indicates that maturation suppression by photoperiod manipulation should be instigated before initiation of oocyte recruitment that commenced during December.

scholarly journals Mobilization of energetic substrates in the endangered catfish Steindachneridion parahybae (Siluriformes: Pimelodidae): changes in annual reproductive cycle in captivity

2018 ◽  
Vol 16 (2) ◽  
Author(s):  
Carlos E. Tolussi ◽  
Aline D. Gomes ◽  
Cristiéle da S. Ribeiro ◽  
Danilo Caneppele ◽  
Renata G. Moreira ◽  
...  
Keyword(s):  
Reproductive Cycle ◽  
Negative Correlation ◽  
Gonadosomatic Index ◽  
Reproductive Period ◽  
Annual Reproductive Cycle ◽  
Plasma Triglycerides ◽  
Glucose Levels ◽  
Adult Females ◽  
In Captivity ◽  
Continuous Feeding

ABSTRACT This study aimed at analyzing the energetic substrate (ES) in the main storage tissues of Steindachneridion parahybae, throughout the reproductive cycle in captivity. Differently from wild, in captivity, feeding is not interrupted during the reproductive period, the females do not spawn spontaneously, and they are sedentary. Adult females were sampled monthly and based on their histology and gonadosomatic index (GSI), ovaries were classified into: previtellogenic (PRV), vitellogenic (VTG), and regression (REG) stages. Ovaries at the VTG stage showed higher protein and lipids levels than at the PRV stage with a positive correlation between these substrates and the GSI. Muscle was the main source of proteins transferred to the ovaries, according to the negative correlation between these organs. Lipids remained unchanged in the liver, which is an important supplier in vitellogenesis, a pattern that probably occurs due to the continuous feeding. Muscular glycogen levels were higher at the VTG and REG than at the PRV stages. Plasma triglycerides were also higher during REG, while glucose levels were more elevated during the VTG stage. These results suggest that with constant food supply, the pattern of deposition of ES in S. parahybae is different from that described for other wild potamodromous species.

Testicular development and serum levels of gonadal steroids during the annual reproductive cycle of captive Japanese sardine

1991 ◽  
Vol 37 (4) ◽  
pp. 381-390 ◽  
Author(s):  
Michiya Matsuyama ◽  
Shinji Adachi ◽  
Yoshitaka Nagahama ◽  
Chikara Kitajima ◽  
Shuhei Matsuura
Keyword(s):  
Reproductive Cycle ◽  
Serum Levels ◽  
Gonadal Steroids ◽  
Testicular Development ◽  
Annual Reproductive Cycle ◽  
Japanese Sardine

Reproductive cycle and gonadal development of Macquarie perch, Macquaria australasica Cuvier (Percichthyidae), in Lake Dartmouth and tributaries of the Murray - Darling Basin, Victoria, Australia

1998 ◽  
Vol 49 (2) ◽  
pp. 163 ◽  
Author(s):  
P. Appleford ◽  
T. A. Anderson ◽  
G. J. Gooley
Keyword(s):  
Reproductive Cycle ◽  
Gonadosomatic Index ◽  
Gonadal Development ◽  
Minimum Size ◽  
Testicular Development ◽  
Murray Darling Basin ◽  
Eastern Australia ◽  
Males And Females ◽  
First Maturity ◽  
Size At First Maturity

The gonadal development, reproductive cycle and growth of Macquarie perch, Macquaria australasica Cuvier, in Lake Dartmouth and selected tributaries of the Murray–Darling River Basin in south-eastern Australia were evaluated. Gonadosomatic index (GSI) and histological analysis were used to determine gonadal development and age and size at first maturity in the resident Lake Dartmouth population. GSI analysis was also used to determine age and size of Macquarie perch at first maturity in the inflowing Mitta Mitta River and other riverine populations within the Goulburn River catchment. Males appeared slightly smaller at first spawning than females at all sites; both sexes were fully mature at four years of age. Differences in size at first maturity were found between the lake and river populations; both males and females of river populations tended to mature at a much smaller size than the fish resident in the lake. Spawning occurred around November. Ovarian and testicular development in this species follows a pattern similar to that of other native Australian percichthyids. The implications for management of recreational fisheries based on minimum size regulations is discussed in relation to site-specific differences in growth rates and size of first maturity of fish.

scholarly journals Permanent germinal epithelium and reproductive cycle of tropical gar Atractosteus tropicus males (Lepisosteiformes: Lepisosteidae), Tabasco, Mexico

2016 ◽  
Vol 64 (4) ◽  
Author(s):  
Otilio Méndez Marin
Keyword(s):  
Reproductive Cycle ◽  
Gonadosomatic Index ◽  
Basic Knowledge ◽  
Germinal Epithelium ◽  
Seminiferous Tubules ◽  
Class Iii ◽  
Wild Populations ◽  
Monthly Basis ◽  
Early Maturation ◽  
Tropical Gar

Tropical gar A. tropicus plays an important ecological role, as a regulator of other fish stocks, in the water bodies of Mexico but their wild populations are being reduced. One conservation alternative is breeding which requires the study of germ and somatic structures of testis to characterize the reproductive cycle, basic knowledge required to create exploitation and conservation models. Three sexually mature males were captured on a monthly basis (N=24), in wild populations of Pomposu lagoon, municipality of Jalpa de Mendez (18°19'59" N - 93°01'12" W), Tabasco, Mexico. The capture technique was trawl net; they were transported live to the Tropical Aquaculture Laboratory, DACBiol, UJAT. Males were sacrificed by decapitation; testis fragments from all of the specimens collected were processes using a routine histological procedure, that consisted of dehydration for ascending etanol series, xylol, and inclusion in paraffin, with a sliding microtome 7µm thick cuts, and were dyed with hematoxylin-eosin (HE). The diameter of 20 seminiferous tubules (Tse), height of germinal epithelium (Egl), gonadosomatic index (GSI) and gonad volume (Gv) were determined on a monthly basis, as well as the gonadosomatic index GSI=PG/PT(100) and the gonad volume vG=4/3 pa2.b. Morpho-physiological characteristics of the testis show that it consists of a network of tubules anastomosed with non-restricted cystic spermatogenesis, and a permanent germinal epithelium. As far as we are concerned, this is the first time that this type of epithelium is reported in Holostei (Lepisosteiformes: Lepisosteidae). Five reproductive classes were identified: Class I Recrudescence, Class II Early Maturation, Class III Intermediate Maturation, Class IV Advanced Maturation, Class V Regression, that when contrasted with the monthly value of the "GSI, GV, Tse" sexual indicators it shows a variation pattern: January-February shows low values with empty testis, with discontinuous germinal epithelium in regeneration; in March spermiogenesis increased and spermatogenesis decreased. Generally speaking, these variations show that at a population level they do not mature synchronously, but with an annual seasonal reproductive cycle with spermatogenesis throughout the year, where temperature and precipitation seem to play an important role as a factor that stimulates reproductive activity and therefore spermiation.

Sign in / Sign up

Export Citation Format

Share Document