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Hamid Niksirat - One of the best experts on this subject based on the ideXlab platform.

  • gonadotropin releasing Hormone Analogue gnrha treatment improves the milt production and sperm motility of endangered caspian brown trout salmo trutta caspius over the course of a spawning season
    Aquaculture Research, 2011
    Co-Authors: Saeed Hajirezaee, Bagher Mojazi Amiri, Mehdi Mehrpoosh, Samane Nazeri, Hamid Niksirat
    Abstract:

    To determine the effect of gonadotropin releasing Hormone-Analogue (GnRHa) treatment on the milt quality of endangered Caspian brown trout, Salmo trutta caspius, the sperm motility (percentage and duration of motility), sperm production (sperm density, spermatocrit and milt volume) and milt pH were measured for GnRHa-treated (the treatment group) and untreated groups (the control group) during the spawning season. For untreated brooders, the values of the motility per cent, sperm density and spermatocrit decreased continuously during the spawning season while the milt volume, duration of motility and milt pH showed only a significant decrease at the end of the season. For GnRHa-treated males, these parameters increased 14 days after GnRHa treatment (first milt collection) and then decreased continuously towards the end of the season. In addition, the values of milt and sperm density yielded per treated male were higher than that in the untreated group, although these were not statistically different. In any case, the total sum of yielded milt from the treatment group over the spawning season was higher than that in the untreated group. In this experiment, significant positive correlations were found between milt parameters as follows: sperm motility vs. milt pH; sperm density vs. spermatocrit; milt volume vs. spermatocrit; and milt volume vs. sperm density. The results show that the treatment of Caspian brown trout by GnRHa can improve the milt quality in terms of sperm motility and sperm production during a spawning season.

  • Gonadotropin releasing Hormone‐Analogue (GnRHa) treatment improves the milt production and sperm motility of endangered Caspian brown trout, Salmo trutta caspius, over the course of a spawning season
    Aquaculture Research, 2011
    Co-Authors: Saeed Hajirezaee, Bagher Mojazi Amiri, Mehdi Mehrpoosh, Samane Nazeri, Hamid Niksirat
    Abstract:

    To determine the effect of gonadotropin releasing Hormone-Analogue (GnRHa) treatment on the milt quality of endangered Caspian brown trout, Salmo trutta caspius, the sperm motility (percentage and duration of motility), sperm production (sperm density, spermatocrit and milt volume) and milt pH were measured for GnRHa-treated (the treatment group) and untreated groups (the control group) during the spawning season. For untreated brooders, the values of the motility per cent, sperm density and spermatocrit decreased continuously during the spawning season while the milt volume, duration of motility and milt pH showed only a significant decrease at the end of the season. For GnRHa-treated males, these parameters increased 14 days after GnRHa treatment (first milt collection) and then decreased continuously towards the end of the season. In addition, the values of milt and sperm density yielded per treated male were higher than that in the untreated group, although these were not statistically different. In any case, the total sum of yielded milt from the treatment group over the spawning season was higher than that in the untreated group. In this experiment, significant positive correlations were found between milt parameters as follows: sperm motility vs. milt pH; sperm density vs. spermatocrit; milt volume vs. spermatocrit; and milt volume vs. sperm density. The results show that the treatment of Caspian brown trout by GnRHa can improve the milt quality in terms of sperm motility and sperm production during a spawning season.

Mehdi Mehrpoosh - One of the best experts on this subject based on the ideXlab platform.

  • Steroid profile of male endangered Caspian brown trout, Salmo trutta caspius Kessler, 1877 after Gonadotropin-Releasing Hormone Analogue treatment
    Journal of Applied Animal Research, 2014
    Co-Authors: Laila Heidari, Vahid Abbasi, Navid Zamani, Mohammad Hossein Shahbani Nouri, Gholam Reza Bishkoul, Mehdi Mehrpoosh
    Abstract:

    The sex steroid profile of Caspian brown trout was investigated after Gonadotropin-Releasing Hormone Analogue (GnRHa) injection throughout the spawning season, i.e. December and January. The values of testosterone (T), 11-Ketotestosterone (11-KT), progesterone (P), cortisol (C) and 17α, hydroxyprogesterone (OHP) were measured for GnRHa treated (the treatment group) and untreated groups (the control group) during the spawning season. In treated males, the values of 11-KT, OHP and C increased 14 days after GnRHa treatment and only showed a significant decrease at the end of the season. Also, the T and P levels showed increases 14 days after GnRHa treatment and then decreased continuously towards the end of the season. In untreated males, sex steroid peaks were observed 27 days after first stripping. In conclusion, our results showed that the GnRHa treatment of Caspian brown trout promotes the final maturation by clear effects on the sex steroid profile.

  • gonadotropin releasing Hormone Analogue gnrha treatment improves the milt production and sperm motility of endangered caspian brown trout salmo trutta caspius over the course of a spawning season
    Aquaculture Research, 2011
    Co-Authors: Saeed Hajirezaee, Bagher Mojazi Amiri, Mehdi Mehrpoosh, Samane Nazeri, Hamid Niksirat
    Abstract:

    To determine the effect of gonadotropin releasing Hormone-Analogue (GnRHa) treatment on the milt quality of endangered Caspian brown trout, Salmo trutta caspius, the sperm motility (percentage and duration of motility), sperm production (sperm density, spermatocrit and milt volume) and milt pH were measured for GnRHa-treated (the treatment group) and untreated groups (the control group) during the spawning season. For untreated brooders, the values of the motility per cent, sperm density and spermatocrit decreased continuously during the spawning season while the milt volume, duration of motility and milt pH showed only a significant decrease at the end of the season. For GnRHa-treated males, these parameters increased 14 days after GnRHa treatment (first milt collection) and then decreased continuously towards the end of the season. In addition, the values of milt and sperm density yielded per treated male were higher than that in the untreated group, although these were not statistically different. In any case, the total sum of yielded milt from the treatment group over the spawning season was higher than that in the untreated group. In this experiment, significant positive correlations were found between milt parameters as follows: sperm motility vs. milt pH; sperm density vs. spermatocrit; milt volume vs. spermatocrit; and milt volume vs. sperm density. The results show that the treatment of Caspian brown trout by GnRHa can improve the milt quality in terms of sperm motility and sperm production during a spawning season.

  • Gonadotropin releasing Hormone‐Analogue (GnRHa) treatment improves the milt production and sperm motility of endangered Caspian brown trout, Salmo trutta caspius, over the course of a spawning season
    Aquaculture Research, 2011
    Co-Authors: Saeed Hajirezaee, Bagher Mojazi Amiri, Mehdi Mehrpoosh, Samane Nazeri, Hamid Niksirat
    Abstract:

    To determine the effect of gonadotropin releasing Hormone-Analogue (GnRHa) treatment on the milt quality of endangered Caspian brown trout, Salmo trutta caspius, the sperm motility (percentage and duration of motility), sperm production (sperm density, spermatocrit and milt volume) and milt pH were measured for GnRHa-treated (the treatment group) and untreated groups (the control group) during the spawning season. For untreated brooders, the values of the motility per cent, sperm density and spermatocrit decreased continuously during the spawning season while the milt volume, duration of motility and milt pH showed only a significant decrease at the end of the season. For GnRHa-treated males, these parameters increased 14 days after GnRHa treatment (first milt collection) and then decreased continuously towards the end of the season. In addition, the values of milt and sperm density yielded per treated male were higher than that in the untreated group, although these were not statistically different. In any case, the total sum of yielded milt from the treatment group over the spawning season was higher than that in the untreated group. In this experiment, significant positive correlations were found between milt parameters as follows: sperm motility vs. milt pH; sperm density vs. spermatocrit; milt volume vs. spermatocrit; and milt volume vs. sperm density. The results show that the treatment of Caspian brown trout by GnRHa can improve the milt quality in terms of sperm motility and sperm production during a spawning season.

P. Epler - One of the best experts on this subject based on the ideXlab platform.

  • Neuropeptide Y stimulates in vivo gonadotropin secretion in teleost fish
    General and Comparative Endocrinology, 1991
    Co-Authors: Bernard Breton, T. Mikolajczyk, W. Popek, K. Bieniarz, P. Epler
    Abstract:

    The effects of the neuropeptide Y (NPY), alone or in combination with a Gonadotropin-Releasing Hormone Analogue, D-Ala6-desGly10-Pro9-Net LHRH (LHRHa), have been studied on the in vivo secretion of the maturational gonadotropin (GtH2) in the rainbow trout Oncorhynchus mykiss and the common carp Cyprinus carpio. Depending on the species, two routes of administration were used: in trout, intraperitoneal injection (20 micrograms/kg body wt); in carp, direct infusion (3 micrograms/kg body wt) into the third ventricle via a temporary brain cannula. In both cases NPY alone induced a twofold increase in GtH2 secretion and peaked 2 to 4 hr administration regardless of the route of injection. The plasma gonadotropin levels returned to basal within 8 hr. The relative increases (peaked secretion/basal secretion) did not differ with the route of injection. When the animals were first treated with NPY and then LHRHa (20 micrograms/kg) 1 hr later, the magnitude of the response to LHRHa was greater in the animals pretreated with NPY, indicating either a potentiation of LHRHa action by NPY or additive effects of the two peptides. The return to basal levels also took longer in fish receiving NPY first. NPY may act directly at the pituitary level or activate central neuromediatory systems.

Saeed Hajirezaee - One of the best experts on this subject based on the ideXlab platform.

  • gonadotropin releasing Hormone Analogue gnrha treatment improves the milt production and sperm motility of endangered caspian brown trout salmo trutta caspius over the course of a spawning season
    Aquaculture Research, 2011
    Co-Authors: Saeed Hajirezaee, Bagher Mojazi Amiri, Mehdi Mehrpoosh, Samane Nazeri, Hamid Niksirat
    Abstract:

    To determine the effect of gonadotropin releasing Hormone-Analogue (GnRHa) treatment on the milt quality of endangered Caspian brown trout, Salmo trutta caspius, the sperm motility (percentage and duration of motility), sperm production (sperm density, spermatocrit and milt volume) and milt pH were measured for GnRHa-treated (the treatment group) and untreated groups (the control group) during the spawning season. For untreated brooders, the values of the motility per cent, sperm density and spermatocrit decreased continuously during the spawning season while the milt volume, duration of motility and milt pH showed only a significant decrease at the end of the season. For GnRHa-treated males, these parameters increased 14 days after GnRHa treatment (first milt collection) and then decreased continuously towards the end of the season. In addition, the values of milt and sperm density yielded per treated male were higher than that in the untreated group, although these were not statistically different. In any case, the total sum of yielded milt from the treatment group over the spawning season was higher than that in the untreated group. In this experiment, significant positive correlations were found between milt parameters as follows: sperm motility vs. milt pH; sperm density vs. spermatocrit; milt volume vs. spermatocrit; and milt volume vs. sperm density. The results show that the treatment of Caspian brown trout by GnRHa can improve the milt quality in terms of sperm motility and sperm production during a spawning season.

  • Gonadotropin releasing Hormone‐Analogue (GnRHa) treatment improves the milt production and sperm motility of endangered Caspian brown trout, Salmo trutta caspius, over the course of a spawning season
    Aquaculture Research, 2011
    Co-Authors: Saeed Hajirezaee, Bagher Mojazi Amiri, Mehdi Mehrpoosh, Samane Nazeri, Hamid Niksirat
    Abstract:

    To determine the effect of gonadotropin releasing Hormone-Analogue (GnRHa) treatment on the milt quality of endangered Caspian brown trout, Salmo trutta caspius, the sperm motility (percentage and duration of motility), sperm production (sperm density, spermatocrit and milt volume) and milt pH were measured for GnRHa-treated (the treatment group) and untreated groups (the control group) during the spawning season. For untreated brooders, the values of the motility per cent, sperm density and spermatocrit decreased continuously during the spawning season while the milt volume, duration of motility and milt pH showed only a significant decrease at the end of the season. For GnRHa-treated males, these parameters increased 14 days after GnRHa treatment (first milt collection) and then decreased continuously towards the end of the season. In addition, the values of milt and sperm density yielded per treated male were higher than that in the untreated group, although these were not statistically different. In any case, the total sum of yielded milt from the treatment group over the spawning season was higher than that in the untreated group. In this experiment, significant positive correlations were found between milt parameters as follows: sperm motility vs. milt pH; sperm density vs. spermatocrit; milt volume vs. spermatocrit; and milt volume vs. sperm density. The results show that the treatment of Caspian brown trout by GnRHa can improve the milt quality in terms of sperm motility and sperm production during a spawning season.

Goro Yoshizaki - One of the best experts on this subject based on the ideXlab platform.

  • spawning induction of blue mackerel scomber australasicus and eastern little tuna euthynnus affinis by oral administration of a crude gonadotropin releasing Hormone Analogue
    Fisheries Science, 2018
    Co-Authors: Kotaro Amezawa, Ryosuke Yazawa, Yutaka Takeuchi, Goro Yoshizaki
    Abstract:

    Scombridae species, such as tunas and mackerels, often do not spawn in land-based fish tanks without Hormone treatment. To induce spawning in various fishes, a Gonadotropin-Releasing Hormone Analogue (GnRHa) is often administered by pellet implantation. Noninvasive administration is desired to induce spawning in scombrids that are sensitive to handling stress. Spawning induction by oral administration has been reported in several fishes, yet this method has not been put into practice in the aquaculture industry since a considerable amount of GnRHa is needed. Utilization of peptide synthesizers is widespread, and antigen-grade GnRHa (AgGnRHa) produced by a custom-peptide supplier is approximately 100-fold cheaper than conventional reagent-grade GnRHa (RgGnRHa), although the purity of AgGnRHa is lower. Here, we confirmed that the spawning induction potency of AgGnRHa was similar to that of RgGnRHa by pellet implantation in blue mackerel Scomber australasicus. Oral administration of AgGnRHa [6.0 mg/kg body weight (BW) per day] showed an equivalent ability to induce spawning of the mackerel as pellet implantation (0.1 mg/kg BW). We could also induce spawning of eastern little tuna Euthynnus affinis by oral administration of the AgGnRHa. Further, the obtained eggs showed higher survival. Thus, the oral delivery of AgGnRHa could be a powerful tool to induce spawning in Scombridae.

  • Spawning induction of blue mackerel Scomber australasicus and eastern little tuna Euthynnus affinis by oral administration of a crude Gonadotropin-Releasing Hormone Analogue
    Fisheries Science, 2018
    Co-Authors: Kotaro Amezawa, Ryosuke Yazawa, Yutaka Takeuchi, Goro Yoshizaki
    Abstract:

    Scombridae species, such as tunas and mackerels, often do not spawn in land-based fish tanks without Hormone treatment. To induce spawning in various fishes, a Gonadotropin-Releasing Hormone Analogue (GnRHa) is often administered by pellet implantation. Noninvasive administration is desired to induce spawning in scombrids that are sensitive to handling stress. Spawning induction by oral administration has been reported in several fishes, yet this method has not been put into practice in the aquaculture industry since a considerable amount of GnRHa is needed. Utilization of peptide synthesizers is widespread, and antigen-grade GnRHa (AgGnRHa) produced by a custom-peptide supplier is approximately 100-fold cheaper than conventional reagent-grade GnRHa (RgGnRHa), although the purity of AgGnRHa is lower. Here, we confirmed that the spawning induction potency of AgGnRHa was similar to that of RgGnRHa by pellet implantation in blue mackerel Scomber australasicus. Oral administration of AgGnRHa [6.0 mg/kg body weight (BW) per day] showed an equivalent ability to induce spawning of the mackerel as pellet implantation (0.1 mg/kg BW). We could also induce spawning of eastern little tuna Euthynnus affinis by oral administration of the AgGnRHa. Further, the obtained eggs showed higher survival. Thus, the oral delivery of AgGnRHa could be a powerful tool to induce spawning in Scombridae.