Reproductive Performance of Pigmented and Albino Female Channel Catfish Induced to Spawn With HCG or Ovaprim (original) (raw)
Related papers
Broodstock management and hormonal manipulations of fish reproduction
General and Comparative Endocrinology, 2010
Control of reproductive function in captivity is essential for the sustainability of commercial aquaculture production, and in many fishes it can be achieved by manipulating photoperiod, water temperature or spawning substrate. The fish reproductive cycle is separated in the growth (gametogenesis) and maturation phase (oocyte maturation and spermiation), both controlled by the reproductive hormones of the brain, pituitary and gonad. Although the growth phase of reproductive development is concluded in captivity in most fishes-the major exemption being the freshwater eel (Anguilla spp.), oocyte maturation (OM) and ovulation in females, and spermiation in males may require exogenous hormonal therapies. In some fishes, these hormonal manipulations are used only as a management tool to enhance the efficiency of egg production and facilitate hatchery operations, but in others exogenous hormones are the only way to produce fertilized eggs reliably. Hormonal manipulations of reproductive function in cultured fishes have focused on the use of either exogenous luteinizing hormone (LH) preparations that act directly at the level of the gonad, or synthetic agonists of gonadotropin-releasing hormone (GnRHa) that act at the level of the pituitary to induce release of the endogenous LH stores, which, in turn act at the level of the gonad to induce steroidogenesis and the process of OM and spermiation. After hormonal induction of maturation, broodstock should spawn spontaneously in their rearing enclosures, however, the natural breeding behavior followed by spontaneous spawning may be lost in aquaculture conditions. Therefore, for many species it is also necessary to employ artificial gamete collection and fertilization. Finally, a common question in regards to hormonal therapies is their effect on gamete quality, compared to naturally maturing or spawning broodfish. The main factors that may have significant consequences on gamete quality-mainly on eggs-and should be considered when choosing a spawning induction procedure include (a) the developmental stage of the gonads at the time the hormonal therapy is applied, (b) the type of hormonal therapy, (c) the possible stress induced by the manipulation necessary for the hormone administration and (d) in the case of artificial insemination, the latency period between hormonal stimulation and stripping for in vitro fertilization.
Aquaculture, 2004
Artificial spawning was induced in female African giant catfish, Heterobranchus bidorsalis by single intramuscular hormone injections of carp pituitary suspensions (CPS) at 4 mg/kg body weight (bw), 1.5 ml of homoplastic pituitary suspension (HPS) per fish or human chorionic gonadotropin (HCG) at 2000 IU/kg bw, over 3 months of rainy season (June to August) in Nigeria. At ambient temperature (27F1 8C), ovulation occurred within 14-18 h post injection. Egg hydration gave 16-20% increase in egg diameter. Hatching rates were high (N84%) and similar for all hormone-treated fish (PN0.05). The percentage normal larvae hatched ranged from 81.6% to 86%. They were reared in 500-l circular tanks and fed initially on zooplankton, followed by brine shrimp nauplii and finally weaned onto commercial fish fry diet. During the larval rearing trials for 30 days, survival rates N82% were achieved. Although the four hormones tested were effective inducers, the use of HPS would save operational costs in fish hatchery management in African countries.
POST OVULATION MANIPULATION IN FEW FRESHWATER CATFISH
The objective was to evaluate the influence of the hormonal induction on the reproductive activity of female freshwater catfish. Control of fish reproduction in captivity is essential for commercial aquaculture. The fish reproductive cycle consists in the growth (gametogenesis) and maturation phase (oocyte maturation), and they are controlled by the reproductive hormones of the brain, pituitary and gonad. Manipulations of reproductive function in cultured fish uses exogenous hormone preparations which act at different levels of the gonad, or the use of synthetic agonists of gonadotropin-releasing hormone. After hormonal induction of maturation, brood stock should spawn spontaneously, however, for many species it is necessary to adapt gamete collection and fertilization in vitro. The main factors that may have significant consequences on gamete quality-mainly on eggs-and the latency period between hormonal injection and stripping for in vitro fertilization.
Aquaculture, 2004
The silver perch (Bidyanus bidyanus Mitchell) (Teraponidae), is a native Australian freshwater fish that, due to its high potential for aquaculture, was introduced to Israeli fish farming. The objective of this study was to find an optimal method for inducing spawning of silver perch. The agents tested for this purpose were: human chorionic gonadotropin (hCG; 150 or 200 IU/kg BW); salmon gonadotropin releasing hormone analogue (sGnRHa at 10, 20, 30, or 40 Ag/kg BW); mammalian GnRH analogue (mGnRHa at 30 Ag/kg) and the combination of sGnRHa at 20 Ag/kg and domperidone at 5 mg/kg BW. Based on spawning success and relative fecundity, sGnRHa at the dose of 30 Ag/kg was found to be more efficient than hCG, mGnRHa or sGnRHa with domperidone. Since domperidone does not improve the GnRHa effect on final oocyte maturation (FOM) and spawning, it is suggested that the dopaminergic inhibition during the stages of FOM in the silver perch is weak. Therefore, the use of GnRHa alone is sufficient to induce spawning in this fish. Immunoreactive gonadotropin (IR-GtH) and estradiol levels increased after a single injection of sGnRHa, and peaked after 24 h. Plasma levels of 17a,20h-dihydroxy-4-pregnen-3-one (17,20-P) also increased significantly 24 h after the injection of mGnRHa, 12 h before spawning, suggesting that 17,20-P is the maturation-inducing steroid in silver perch. In order to reveal whether the heterologous gonadotropin may elicit an immunological reaction, silver perch was subjected to prolonged treatment with hCG. This treatment resulted in no detectable titer of antibodies against the mammalian gonadotropin. In conclusion, although hCG has no deleterious effects in this fish, and is the more commonly used for spawning induction, sGnRHa at 30 Ag/kg is the recommended
Hormone-induced spawning of cultured tropical finfishes
1989
Commercially important tropical freshwater and marine finfishes are commonly spawned with pituitary homogenate, human chorionic gonadotropin (HCG) and semi-purified fish gonadotropins. These preparations are often administered in two doses, a lower priming dose followed a few hours later by a higher resolving dose. Interval between the first and second injections may vary from 3-24 hours depending on the species. Variable doses are used even for the same species and may be due to variable potencies of the gonadotropin preparations. Synthetic analogues of luteinizing hormone-releasing hormone (LHRHa) are becoming widely used for inducing ovulation and spawning in a variety of teleosts. For marine species such as milkfish, mullet, sea bass, and rabbitfish, a single LHRHa injection or pellet implant appears to be effective. Multiple spawnings of sea bass have also been obtained following a single injection or pellet implant of a high dose of LHRHa. In a number of freshwater fishes such as the cyprinids, LHRHa alone however has limited efficacy. Standardized methods using LHRHa together with the dopamine antagonists pimozide, domperidone and reserpine have been developed for various species of carps. The technique may also be applicable for spawning marine teleosts that may not respond to LHRHa alone or where a high dose of the peptide is required. Although natural spawning is the preferred method for breeding cultivated fish, induced spawning may be necessary to control timing and synchrony of egg production for practical reasons.
Aquaculture, 1988
Induced spawning of maturing milkfish (Chanos chanos) using human chorionic gonadotropin and mammalian and salmon gonadotropin releasing hormone analogues. Aquaculture, 73: 333-340. The response of maturing female milkfish to D-Ala'-des Gly" mammalian GnRH ethylamide (mGnRH-A), D-Arg'-des Gly" salmon GnRH ethylamide (sGnRH-A) and human chorionic gonadotropin (hCG) was investigated. The GnRH analogues and hCG were equally effective when administered by intramuscular injection at doses of 10 pg/kg and 100 pg GnRH-A/fish or 1000 IU hCG/fish. All of the females injected with HCG and 87.5% (7/8) of females injected with GnRH-A spawned. Pellet implantation of the GnRH analogues, however, was less effective based on 100 pg of pellet per fish, which provided from 20 to 36 ,ug of analogue per kg fish. Fish implanted with mGnRH-A or sGnRH-A showed responses which varied from oocyte hydration to spawning. Only 3/7 implanted with mGnRH-A and l/7 implanted with sGnRH-A spawned; in the latter group, the average egg diameter was ll-17% smaller at the time of treatment compared with the other treated groups. Except for one, all fish with egg diameters above 0.65 mm had hydrated/ ovulated oocytes or spawned. Females which spawned had egg diameters above 0.71 mm.
Aquaculture Research, 1994
Effects of low doses of salmon gonadotropin (SG-GIOO) and three , deoxycorticosterone (DOC) and progesterone -individually, or combinations of steroid with SG-GlOO, on ovulation and hatching in Clarias batrachus (L.) were investigated. None of the steroids at any of the three different dose levels (1 |xg, 1-5 ^.g and 2 (ig/g BW) could induce ovulation when injected alone. SG-GIOO at a dose level of 10 M.g/g BW was not effective but at the dose level of 15 (jig/g BW it could induce ovulation. All the three steroids at their lowest doses (1 ^.g/g BW) when injected in combination with SG-GIOO (lOng/g BW) were significantly effective in inducing ovulation. When hatching percentage was taken into account, 17a,20p-diOHprog in combination with SG-GIOO was found to be the most effective combination in comparison with other treatments.