The Involvement of Gonadotropin-Inhibitory Hormone (GnIH) in Fish Reproduction

2021 ◽  
pp. 139-160
Author(s):  
Pravesh Kumar
Keyword(s):  
Fish Reproduction ◽  
Gonadotropin Inhibitory Hormone

Analysis of the rates of development and growth of Brachymystax lenok Savinovi during artificial reproduction by the industrial method

2020 ◽  
pp. 40-49
Author(s):  
S. Assylbekova ◽  
N. Badryzlova ◽  
L. Kushnikova
Keyword(s):  
Water Temperature ◽  
Fish Reproduction ◽  
Optimal Conditions ◽  
Artificial Reproduction ◽  
Fish Products ◽  
Rate Of Development ◽  
Stage Of Development ◽  
East Kazakhstan ◽  
Brachymystax Lenok ◽  
The Moment

The article presents the results of the first research on artificial reproduction in industrial conditions of the endemic, narrow-areal subspecies of Brachymystax lenok Savinovi, which lives in lake Markakol, East Kazakhstan region. The indicators of the heat sum characteristic for each stage of development, the rate of development and growth of the Markakolsky lenok from the moment of pre-breeding to late juveniles are described. To develop technological approaches for artificial fish reproduction, one of the most important points is to determine the optimal conditions for each stage and assess the risks (loss of fish products). At the stage of insemination and transportation of eggs to the place of incubation, the loss was 50 %. The largest losses of fish products were registered during the incubation stage. The most painlessly passed the period of holding and lifting on the float, where the loss was only 3 %. When growing pre-larvae and larvae in the pool, the daily waste did not exceed 1 %. Small-sized animals that were unable to adapt to artificial feeds fell into the waste. Losses during this period amounted to 15 % of the previous stage. In General, the yield of juveniles from the moment of fertilization to the end of the experiment was 16 %. The crucial factor in the development and growth of Lenok Markakolosky is the temperature regime. For the period of embryonic development, the most favorable water temperature is 7–8 °C. From the moment of hatching, the water temperature must be increased to 10–12 °C, and the optimal temperature for the cage growing of fingerlings varies from 12 to 14 °C.

Responses in a Fathead Minnow (Pimephales promelas) Lifecycle Test and in Wild White Sucker (Catostomus commersoni) Exposed to a Canadian Bleached Kraft Mill Effluent

2010 ◽  
Vol 45 (2) ◽  
pp. 187-200 ◽  
Author(s):  
Joanne L. Parrott ◽  
L. Mark Hewitt ◽  
Tibor G. Kovacs ◽  
Deborah L. MacLatchy ◽  
Pierre H. Martel ◽  
...  
Keyword(s):  
Egg Production ◽  
Fathead Minnow ◽  
Pimephales Promelas ◽  
Fish Reproduction ◽  
White Sucker ◽  
Catostomus Commersoni ◽  
Liver Size ◽  
Paper Mill Effluent ◽  
Kraft Mill Effluent ◽  
Kraft Mill

Abstract To evaluate currently available bioassays for their use in investigating the causes of pulp and paper mill effluent effects on fish reproduction, the responses of wild white sucker (Catostomus commersoni) collected from the receiving environment at the bleached kraft mill at La Tuque, Quebec, were compared with responses of fathead minnow (Pimephales promelas) exposed to effluent in a laboratory lifecycle test. White sucker collected at effluent exposed sites had increased liver size but none of the reproductive effects that had been documented in earlier field studies at this site. Exposure to 1, 3, 10, 30, and 100% bleached kraft mill effluent (BKME) in the lab led to significantly decreased length, but increased weight and liver size in male fathead minnow. Female length was also decreased and liver size was increased at high effluent exposures. Most effluent concentrations (1 to 30%) significantly increased egg production compared with controls. The fathead minnow lifecycle assay mirrored the effects seen in wild fish captured downstream of the BKME discharge. These results will be used to select short-term fish tests for investigating the causes of and solutions to the effects of mill effluents on fish reproduction.

The Benefits of Biotreatment for Reducing the Effects of Pulp and Paper Mill Effluents on Fish Reproduction in Laboratory Tests

2008 ◽  
Vol 43 (2-3) ◽  
pp. 161-171 ◽  
Author(s):  
Pierre Martel ◽  
Tibor Kovacs ◽  
Virginie Bérubé
Keyword(s):  
Laboratory Tests ◽  
Egg Production ◽  
Pimephales Promelas ◽  
Paper Mill ◽  
Pulp And Paper ◽  
Reproductive Capacity ◽  
Fish Reproduction ◽  
Pulp And Paper Mill ◽  
Paper Mill Effluents ◽  
Gonad Size

Abstract Pulp and paper mill effluents have been reported to cause changes in reproductive indicators of fish in laboratory and field studies. These changes include reduced egg production and gonad size, and altered hormone levels and expression of secondary sex characteristics. We examined the performance of biotreatment plants for their potential in abating effects of pulp and paper mill effluents on fish reproduction under laboratory conditions. A bleached kraft mill effluent (BKME) treated in an aerated lagoon and a thermomechanical pulp mill effluent (TMPE) treated by aerobic sludge in a sequential batch reactor were selected for study. Mature fathead minnows (Pimephales promelas) were exposed to effluents before and after biotreatment under continuous renewal conditions for 21 days. Egg production was monitored daily, while morphometric parameters (length, weight, gonad size), secondary sexual characteristics, and steroid hormone and vitellogenin levels were measured at the end of the effluent exposure. The effluent from both mills before biotreatment impaired the reproductive capacity of minnows (egg production) at concentrations of 10 and 20% vol/vol, but not at 2% vol/vol. Exposure to biotreated effluents from both mills at concentrations of 2, 10, 20, and 40% vol/vol caused no significant differences in overall reproductive capacity of minnows as compared with controls. These results indicate that biotreatment can significantly improve the quality of a BKME and an effluent from a TMP mill with respect to the reproductive capacity of fish as determined in laboratory tests.

scholarly journals Differential Regulation of Gonadotropins as Revealed by Transcriptomes of Distinct LH and FSH Cells of Fish Pituitary

2021 ◽  
Vol 22 (12) ◽  
pp. 6478
Author(s):  
Lian Hollander-Cohen ◽  
Matan Golan ◽  
Berta Levavi-Sivan
Keyword(s):  
Follicle Stimulating Hormone ◽  
Differential Regulation ◽  
Receptor Expression ◽  
Hormone Regulation ◽  
Fish Reproduction ◽  
Cell Type ◽  
Conserved Genes ◽  
Transgenic Tilapia ◽  
And Function ◽  
Direct Regulation

From mammals to fish, reproduction is driven by luteinizing hormone (LH) and follicle-stimulating hormone (FSH) temporally secreted from the pituitary gland. Teleost fish are an excellent model for addressing the unique regulation and function of each gonadotropin cell since, unlike mammals, they synthesize and secrete LH and FSH from distinct cells. Only very distant vertebrate classes (such as fish and birds) demonstrate the mono-hormonal strategy, suggesting a potential convergent evolution. Cell-specific transcriptome analysis of double-labeled transgenic tilapia expressing GFP and RFP in LH or FSH cells, respectively, yielded genes specifically enriched in each cell type, revealing differences in hormone regulation, receptor expression, cell signaling, and electrical properties. Each cell type expresses a unique GPCR signature that reveals the direct regulation of metabolic and homeostatic hormones. Comparing these novel transcriptomes to that of rat gonadotrophs revealed conserved genes that might specifically contribute to each gonadotropin activity in mammals, suggesting conserved mechanisms controlling the differential regulation of gonadotropins in vertebrates.

scholarly journals Developmental changes in gonadotropin-inhibitory hormone in the Japanese quail (Coturnix japonica) hypothalamo-hypophysial system

2003 ◽  
Vol 178 (2) ◽  
pp. 311-318 ◽  
Author(s):  
T Ubuka ◽  
M Ueno ◽  
K Ukena ◽  
K Tsutsui
Keyword(s):  
Japanese Quail ◽  
Median Eminence ◽  
Anterior Pituitary ◽  
Coturnix Japonica ◽  
Developmental Changes ◽  
External Layer ◽  
Mature Peptide ◽  
Gonadotropin Release ◽  
Gonadotropin Inhibitory Hormone ◽  
Precursor Mrna

We previously isolated a novel dodecapeptide containing a C-terminal -Arg-Phe-NH(2) sequence, SIKPSAYLPLRF-NH(2) (RFamide peptide), from the Japanese quail (Coturnix japonica) brain. This novel quail peptide was shown to be located in neurons of the paraventricular nucleus (PVN) and their terminals in the median eminence (ME), and to decrease gonadotropin release from cultured anterior pituitary in adult birds. We therefore designated this peptide gonadotropin-inhibitory hormone (GnIH). Furthermore, a cDNA encoding the GnIH precursor polypeptide has been characterized. To understand the physiological roles of this peptide, in the present study we analyzed developmental changes in the expressions of GnIH precursor mRNA and the mature peptide GnIH during embryonic and posthatch ages in the quail diencephalon including the PVN and ME. GnIH precursor mRNA was expressed in the diencephalon on embryonic day 10 (E10) and showed a significant increase on E17, just before hatch. GnIH was also detected in the diencephalon on E10 and increased significantly around hatch. Subsequently, the diencephalic GnIH content decreased temporarily, and again increased progressively until adulthood. GnIH-like immunoreactive (GnIH-ir) neurons were localized in the PVN on E10, but GnIH-ir fibers did not extend to the ME. However, GnIH-ir neurons increased in the PVN on E17, just before hatch, and GnIH-ir fibers extended to the external layer of the ME, as in adulthood. These results suggest that GnIH begins its function around hatch and acts as a hypothalamic factor to regulate gonadotropin release in the bird.

Corticosteroids: Friends or foes of teleost fish reproduction?

2009 ◽  
Vol 153 (3) ◽  
pp. 242-251 ◽  
Author(s):  
S. Milla ◽  
N. Wang ◽  
S.N.M. Mandiki ◽  
P. Kestemont
Keyword(s):  
Teleost Fish ◽  
Fish Reproduction
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