Carp Pituitary Extract Research Articles

Comparative Study of Synthetic Hormones Ovaprim and Pitutary Extract in Induced Breeding of Indian Major Carps ( IMC)

In the present study during June 2020- May 2021 observed the spawing response of ovaprim compard with pituitary extract in Indian major carps (IMC). The research work was carried out at fish breeding center, Jayakwadi Paithan 60 K.M away from Aurangabad (M.S) India. Total ten trial doses of carp pituitary extract (CPE) used for induced breeding in Indian major carps i.e. Catla catla , Labeo rohita and Cirrhinus mrigala. The percentage of fertilization ranged (88.11-97.94%) was found with ovaprim treatment and (53.19-85.48 %) with pituitary extract treatment. The percentage hatchling ranged (74.70-95.92 %) with ovaprim treatment and (60- 58.82%) with pituitary extract treatment.

Markers for egg quality in European eel derived from offspring of females subjected to different gonadotropic treatments

Broodstock management techniques in general, and gonadotropic treatments for vitellogenesis induction in particular, can influence the maternal provisioning of different compounds to the eggs, thus affecting embryo and larval competence. Among these, the abundance of certain transcripts as well as lipid content and fatty acid composition have been used as egg quality markers alongside other egg morphological parameters, such as egg size and the occurrence of abnormal cleavages during the first stages of embryonic development. Here, we evaluated the use of different markers of egg quality from farmed-raised European eel, Anguilla anguilla, broodstock reared on the same formulated diet but subjected to different pituitary extract administration schemes: weekly injections of salmon pituitary extract (SPE) in a constant dose or weekly injections of carp pituitary extract (CPE) at a stepwise increasing dose. Egg batches were categorized in two quality groups (high and low) according to their survival to the first feeding larval stage. In agreement with previous studies, unfertilized eggs and 4-h post fertilization embryos (16-cell stage) from SPE treated females had higher epcam expression levels than CPE ones, which is a molecule involved in cell-cell adhesion. When comparing treatments, batches from the SPE treatment had a lower incidence of cleavage abnormalities which could originate from compromised cell adhesion. On the other hand, this difference was not observed when comparing high-quality batches (i.e. those surviving up to the first-feeding stage) and low-quality ones. From the five genes analysed: epcam, dcbld1, plec, cenpf, and cenpk, only the latter had a differential expression between high- and low-quality groups both in unfertilized eggs and 4 h-post-fertilization embryos. This gene, cenpk, is involved in kinetochore assemblage during cell division and appears to be promising as egg quality marker in European eel in combination with epcam and dcbld1. Common biomarkers, such as egg size, total protein and lipid content, were similar between groups. However, although fatty acid composition was similar between quality groups, DHA and EPA content in unfertilized eggs was affected by the gonadotropic treatment applied to the female broodstock, and higher for the CPE treated females than the SPE ones. This entails that the hormonal treatments applied for vitellogenesis induction can influence the amount of specific fatty acids being transferred to the eggs, even for female broodstock that were fed the same high-quality diet.

Effect of carp pituitary extract (CPE) and human chorionic gonadotropin (hCG) on reproductive performance and larval production of the Egyptian Sole Solea aegyptiaca

Effect of carp pituitary extract (CPE) and human chorionic gonadotropin (hCG) on reproductive performance and larval production of the Egyptian Sole Solea aegyptiaca

Comparing carp pituitary gland extract and ovaprim in induced breeding of stinging Catfish

Comparing carp pituitary gland extract and ovaprim in induced breeding of stinging Catfish

Ovarian lavage / artificial insemination method as an alternative approach for controlled reproduction of the northern pike (Esox lucius)

This study aimed to compare the effectiveness of the ovarian lavage / artificial insemination method with the traditional hormonal administration and fertilization methods over the artificial reproduction of the northern pike (Esox lucius). For this purpose, groups of five females were treated as follows: intraperitoneal injection of saline (C1); ovarian lavage with saline (C2); intraperitoneal injection of carp pituitary extract (CPE, T1); ovarian lavage with CPE (T2); intraperitoneal injection of CPE and ovarian lavage with semen after 72 h (T3); ovarian lavage with CPE and ovarian lavage with semen after 72 h (T4). According to the results, no fish ovulated in the control groups (C1 and C2). There were no significant differences (n.s.) among experimental treatments (P > 0.05, n.s.) in the reproductive parameters, such as latency time, ovulation rate, stripped egg amount, and pseudo-gonadosomatic index. The lowest fertilization rate (54.8%) was observed in the T4 treatment and significantly differed from the T1 and T2 treatments (P < 0.05). Moreover, the highest survival at swim-up stage was measured in the T4 treatment with a significant difference compared to the T1 group (P < 0.05). The survival at the eyed-egg stage, hatching rate, and malformations were similar (P > 0.05, n.s.) in all applied strategies. The results demonstrated that the ovarian lavage / artificial insemination method could be applied to control northern pike reproduction, like the traditional fertilization method. Consequently, this novel technique can be suggested as an alternative strategy to facilitate the hatchery operations in the controlled reproduction of this species.

Relationship between seminal plasma composition and sperm quality parameters of the catfish Pseudoplatystoma reticulatum

Abstract Sperm quality is a fundamental parameter for the effective reproduction of fish in captivity and the development of reproductive techniques, such as semen cryopreservation. This study aimed to determine the composition of the seminal plasma of Pseudoplatystoma reticulatum and analyze the relationships between plasma components and sperm characteristics. Nine males were induced to spermiation with carp pituitary extract in the reproductive period of the species (November and December/2019). Semen characteristics were evaluated: subjective sperm motility, motility, duration, released sperm volume, sperm concentration, pH, osmolality, and seminal plasma composition, including levels of calcium, chloride, sodium, magnesium, potassium, glucose, fructosamine, triglycerides, and total protein. To determine the relationship between seminal plasma components and sperm motility parameters, a principal component analysis (PCA) was performed. The seminal plasma of P. reticulatum is composed mainly of the Na+ ion and organic components such as protein and glucose. Through PCA, it was observed that sperm motility had a strong positive correlation with motility time, sperm concentration, and total protein and a negative correlation with osmolality and fructosamine.

The investigation of post-thaw chilled storage and the applicability of large-scale cryopreservation in chub (Squalius cephalus) sperm

Chub (reophillic cyprinids) is one of the most sensitive bioindicator fish of environmental changes following anthropogenic activities. The improvement of different biotechnological procedures could help support its conservation and strengthen the natural populations. The aim of this study was to compare the effects of two different hormonal agents (carp pituitary extract and Ovopel™) on various motility parameters (pMOT-%, DAP-μm, VCL μm s−1, VSL-μm s−1, LIN-%, ALH-μm, BCF-Hz) of fresh and cryopreserved/thawed sperm (stored at 4 °C for 6 h). Additionally, we sought to develop a novel, large-scale cryopreservation method for chub sperm, assessing freezing methods (Styrofoam box and a controlled-rate freezer) and different containers (0.5, 5 mL straw and 4 mL cryotube) for sperm cryopreservation. The results of this study indicated no difference between the carp pituitary extract and Ovopel treated groups in either the fresh or frozen/thawed sperm (at 0, 3, 6, hour post thawing, P = 0.4351). In contrast, the quality of the thawed chub sperm was negatively affected after 3 h chilled storage in both hormonal treatments (P = 0.0036, P < 0.0001). When assessing the motility parameters of the sperm between the 5 mL straw and 4 mL cryotube groups cryopreserved in a Styrofoam Box, no difference was observed (P = 0.103). Additionally, sperm loaded in 4 mL cryotubes showed no difference in motility when cryopreserved with either the Styrofoam box or controlled-rate freezer methods (P = 0.109). A similar hatching rate was observed in sperm preserved using the Styrofoam box (35 ± 7 %) and controlled rate freezer (25 ± 9 %) methods (P = 0.300). In a second fertilization trial, hatching rate was similar between control (72 ± 19 %) and cryopreserved (4 mL cryotube and Styrofoam box, 61 ± 5 %) groups. (P = 0.257). Based on our findings and its standard features (less species specific, precise dose calculation), Ovopel can be a good candidate for the stimulation of spermiation in chub sperm prior to cryopreservation. Furthermore, our study presents a novel and applicable method for the large-scale cryopreservation of chub sperm.

Evaluation of the Reproductive Performance of Females of Anguilla anguilla Characterized by Different Levels of Silvering

The European eel, Anguilla anguilla (Linnaeus, 1758), is a species of high conservation and commercial value. Also, with a high aquacultural value, it was one of the most farmed species in Europe before its decline. Conservation measures for this species are currently being implemented, some of which are the release of adults to allow them to migrate to spawning grounds and artificial reproduction to minimise the impact of overfishing. Much progress has been made regarding the closing of the life cycle, but several problems remain to be solved, such as the weaning and growth of larvae. In this regard, the study of local populations and the identification of the best spawners could be a good way forward as it would help to identify spawners with high reproductive potential and good offspring quality. In this study, we compared the reproductive performance of female eels from migratory areas of the Northern Adriatic Sea at different maturation stages (10 pre-migrant stage; 10 migrant stage), treating both groups with the same hormonal protocol (weekly carp pituitary extract, injection of 17α,20β-Dihydroxy-4-pregnen-3-one at complete oocyte maturation). The research showed that eels at the beginning of metamorphosis (SI III), i.e., eels not yet ready to undertake migration, achieve reproductive performance equal to that of eels ready for migration (SI IV). Their performance was on par in both qualitative and quantitative terms. The optimal results in hatching (with values of 65.8 ± 3.2% for pre-migrant and 68.2 ± 4.1% for migrant) and survival rates (with value of 25.7 ± 5.4% pre-migrants; 27.2 ± 3.7% migrants), as well as the results about the time to reach full gonadal maturation, may have positive implications when considering release and restocking measures.

Human Chorionic Gonadotropin Enhancement of Early Maturation and Consequences for Reproductive Success of Feminized European Eel (Anguilla anguilla)

To induce oocyte development, eels are weekly injected with salmon or carp pituitary extract (CPE). The weekly handling and hormone peaks result in inferior oocyte quality; therefore, alternative treatments that improve oocyte quality and reproductive success require investigation. The enhancement of early sexual maturation by a single injection with human chorionic gonadotropin (hCG), administered prior to CPE treatment, was investigated. Fifty feminized eels were subjected to simulated migration, after which eels received either a hCG or a sham injection. After two months, the hCG-treated eels showed an increase in eye size, gonadosomatic index (GSI), and plasma 11-ketotestosterone concentration, when compared with the sham-injected controls. The hCG-treated eels showed increases in oocyte diameter and lipid area, and in ovarian expression of aromatase (cyp19), follicle stimulating hormone receptor (fshr) and lipoprotein lipase (lpl). Yolk was present in the oocytes of the hCG-treated eels, not yet in the oocytes of the controls. The hCG-induced deposition of yolk may relate to early-life treatment with 17β-estradiol during feminization. hCG-treated eels required four CPE injections less to mature than the controls. hCG treatment may benefit reproductive success in feminized eels by initiating vitellogenesis and reducing the hypophysation period, although larvae were obtained from most females in both groups.

Induced Spawning of Grass Carp Ctenopharyngodon idella, Using Common Carp Pituitary Extract with Domperidone

To test the efficacy of the technique of using dopamine antagonists with pituitary extracts, experiments were conducted in July, 2022, at Masab Al Sen (Al Sen estuary) Fish Farm and Hatchery, General Commission for Fisheries Resources, Syria. In all, 18 sets (2 female x 4 male in each set) were tried individually. 9 sets were treated with domperidone (DOM) and carp pituitary extract (CPE) and they constituted the experimental sets, while the rest 9 were treated with CPE and formed the control sets. The ovulation ratio, absolute fecundity, relative fecundity (number of eggs/kg), fertilization rate and hatching rate was 92.85%, 384645 ± 70990 eggs, 56853.22 ± 5385.68 eggs/kg, 80.02% and 61.54%, respectively in the experimental sets whereas it was 92.85%, 355172 ± 53008 eggs, 52059.73 ± 3853.71 eggs/kg, 72.50% and 54.46% respectively in case of control sets. Hatching occurred within 20 h and 45 min to 21 h after fertilization in the experimental sets whereas it was 20 h and 45min to 21 h and 20 min in case of control sets at 26-26.5°C. It was observed that body weight has positive influence on absolute fecundity (r = 0.98, 0.99) and relative fecundity (0.97,0.97) in case of experimental sets and control sets respectively.

Induced reproduction of yellow-tailed lambari (Astyanax lacustris) with Ovopel® and buserelin acetate as alternatives to the protocol with carp pituitary extract.

The objective of this study was to evaluate reproductive traits in adults of Astyanax lacustris subjected to different spawning inducers. The study involved 240 females (12.54 g ± 2.33 and 7.66 cm ± 0.63 cm) and 240 males (5.83 g ± 0.39 g and 6.14 cm ± 0.64 cm), all at reproductive age. Three different inducers were evaluated: (i) 0.4 pellets of Ovopel®/kg of body weight; (ii) 0.5 ml of buserelin acetate/kg of body weight; and (iii) carp pituitary extract (CPE) (5.5 mg CPE/kg body weight for females and 2.5 mg CPE/kg body weight for males), as well as saline solution (without hormone). The degree-hours for spawning were greater (P<0.05) for the Ovopel® treatment (with 204.93) than in the treatment with CPE (183.2). Ovary weight and gonadosomatic index were higher (P<0.05) in CPE and Ovopel® treatments when compared to buserelin acetate. The number of oocytes per female, absolute and relative fecundity were greater (P<0.05) for Ovopel® and CPE treatments. Fertilization rate was higher (P<0.05) in treatment with buserelin acetate (82.3%) in relation to Ovopel® (72.33%) and CPE (62.40%) treatments, and the highest (P<0.05) hatching rates were achieved with buserelin acetate and Ovopel®. The number of larvae per female body weight was greater (P<0.05) when Ovopel® was used. In conclusion, Ovopel® proves to be a more effective reproductive inducer for induced reproduction of A. lacustris when compared to CPE and buserelin acetate.

Dimethyl acetamide and dimethyl sulfoxide associated at glucose and egg yolk for cryopreservation of Pseudoplatystoma corruscans semen

Abstract This study aimed to develop a protocol for the cryopreservation of Pseudoplatystoma corruscans semen. For this, mature males were hormonally induced with a single dose of carp pituitary extract (5 mg/kg body weight). Semen was collected and evaluated. Two cryoprotectants were tested to compose the diluents: dimethyl acetamide (DMA) and dimethyl sulfoxide (Me2SO), in two concentrations (8% and 10%), + 5.0% glucose + 10% egg yolk. The semen was diluted in a 1: 4 ratio (semen: extender), packed in 0.5 mL straws and frozen in a dry shipper container in liquid nitrogen vapors. After thawing, sperm kinetics, sperm morphology and DNA integrity of cryopreserved sperm were evaluated. Pseudoplatystoma corruscans males produced semen with sperm motility &gt; 80%. After thawing, all treatments provided semen with total sperm motility &gt; 40%, with no significant difference (P &lt; 0.05) between them, as well as between the other sperm kinetic parameters evaluated. The treatments with DMA provided a smaller fragmentation of the DNA of the gametes. Sperm malformations were identified in both fresh and cryopreserved semen, with a slight increase in these malformations being identified in sperm from thawed P. corruscans semen samples.

Determinação da concentração espermática de tambaqui (Colossoma macropomum) por espectrofotometria

Abstract To assist the reproductive management of tambaqui (Colossoma macropomum) males in laboratory and commercial fish farming, a linear regression model was obtained from concentration curves using the spectrophotometric method. Twenty-two tambaqui males with an average age of three years old were selected and divided into two groups containing 11 animals each. Both groups alternately received a single dose of carp pituitary extract (CPE; 2.0 mg/kg body weight, intracoelomic). Sperm was collected 14 h after hormonal treatment and diluted (1:4000; sperm:formaldehyde saline). The concentration was estimated by counting spermatozoa in a Neubauer chamber and by using a spectrophotometer (λ=540 nm). Individual sperm concentration ranged from 11.40 to 71.13 × 109 sperm/mL. The degree of transmittance ranged from 62.1% to 95.0%. There was a significant correlation (r2 = 0.966; p &lt; 0.0001) between sperm concentration analyzed in a Neubauer chamber and transmittance at 540 nm. Analysis by spectrophotometry and the prediction provided by the equation Y=100.293 - 0.509X proved to be an efficient and fast method for estimating sperm concentration in tambaqui and can be used in routine procedures in artificial fish reproduction laboratories.

Effect of Carp Pituitary Extract, HCG and Mix of Them on Fecundity, Larvaes Production, Blood Sex Hormones and Biochemical Parameters of the African Catfish (Clarias gariepinus

Effect of Carp Pituitary Extract, HCG and Mix of Them on Fecundity, Larvaes Production, Blood Sex Hormones and Biochemical Parameters of the African Catfish (Clarias gariepinus

Assessment of the Effects of Some Reproductive Hormones on Aspects of Reproductive Biology of Clarias gariepinus and Heterobranchus longifilis

Protein food sources are highly recommended for a healthy living and fish is one of the most recommended protein sources. This research was aimed at enhancing fish seed propagation and the effects of four fish reproductive hormones (Ovaprim, Carp pituitary extract, human chorionic gonadotropin, and Deoxy-corticosterone acetate) on some aspects of reproductive biology of Heterobranchus longifilis and Clarias gariepinus bought from Itu head-bridge, Akwa Ibom state. Sixty mature broodstocks (both males and females) of each species weighing 2.0 kg were used in this study. The experimental procedure was made up of four experimental groups (treatments) with three replicates including control. Each group was administered with the appropriate dosage of the respective reproductive hormone. The mean relative fecundity in both species using ovaprim and human chorionic gonadotropin showed no significant difference, while carp pituitary extract showed significant difference (p &lt; 0.05) in both species. The mean egg hatchability values in the species administered with ovaprim, human chorionic gonadotropin and carp pituitary extract were similar (p &gt; 0.05). Mean values were significantly different (p &lt; 0.05) from those administered with Deoxy-corticosterone acetate. The mean fry survival rates in both species were not significantly different (p &gt; 0.05) with human chorionic gonadotropin, carp pituitary extract and ovaprim, but showed significant difference (p &lt; 0.05), except Deoxy-corticosterone acetate. Female brooders in the control tanks showed no result throughout the study. Treatments with the hormones yielded better result, except in the case of Deoxy-corticosterone acetate. It could be concluded that reproductive hormones, especially ovaprim and carp pituitary are better for breeding H. longifilis and C. gariepinus. The results from the study are crucial in encouraging fish seed propagation through the application of artificial hormones.

Effeciency of Procedural Use of Hormonal Agent in Propagation of Clarias gariepinus

Administration procedures of some hormones including single, double and multiple induction protocols were investigated to determine the implications of different induction process in propagation of Clarias gariepinus. The hormones studied were ovulin, Carp pituitary extract (CPE) and gonopore. A total of 36 Clarias gariepinus of the same age comprising 27 females and 9 males were used for the study. Eggs produced among treatments were fertilized with pooled sperm from a total of 3 males per hormonal treatment. Propagation was assessed by fecundity, fertilization, hatchability and larval survival. Highest egg production was recorded at double inductions with ovulin and CPE while highest egg production was observed in single induction with gonopore. There was significant disparity (P&lt;0.05) in fertilization and hatchability percentages. Best fertilization and hatching rate was recorded with ovulin at single induction (80.2%) and ovulin at multiple inductions (81.9%) respectively. There was significant difference (P&lt;0.05) in number of larvae realized among the treatments. Highest larval survival was recorded with gonopore at single induction (68.1%). Findings from the study showed that hormone type and mode of administration are important in propagation of C. gariepinus. The study recommended double inductions in usage of Ovulin and CPE and single induction with gonopore. Adopting best procedural technology in usage of specific hormone is necessary for mass production of Clarias gariepinus seeds.

Artificial Propagation of Gattan (Barbus xanthopterus Heckel) in Basrah- Iraq

Gattan (Barbus xanthopterus Heckel) was artificially propagated in marine science center fish hatchery- University of Basrah, During Spring 2009. The brooders were collected from Al-Huwaizah Marsh (which were bring in to the hatchery directly) and Al-Therthar reservoir (which were reared in earthen ponds). The efforts to collect brooders from Al- Kut dam were failed, because of water shortage. The brooders ranged between 1500-6500 gr in weight and II-V year age. The gonads of Al- Huwaizah marsh brooders were in good maturity stage, The GSI was ranged between 3.66-11.03%, and in ripe maturity stage, while the brooder's gonads of Al-Therthar reservoir were in developing stage, with GSI ranged between 1.1-1.3 %, and this result was agreed with the previous studies. "Aquacalm" substance was used for sedation; it was found that the best concentration for the sedation of Gattan was 1 ppm. The best treatment for the induced spawning of Gattan was the Carp pituitary gland extract (CPG), with a dosage of 6 mg/ kg, in two injections, each with 3 mg/kg, with 12 h interval. Two fishes from Al- Therthar reservoir were responding to this treatment, with weight of 1750 and 1500g. 350 g of good quality eggs was obtained from the first fish. All the males give small quantity of milt the milt was added to the eggs without water for mixing. Then the eggs were covered with water for. Fertilization rate was 88%. The fertilized eggs washed with water only, from brooders rearing tank for 20min. Then incubated in Zoug jars with a rate off 70 g / jar, incubation temperature ranged between 22- 24°C. The hatching completed after 72 h, with 80 % hatching rate. The larvae start feeding after three days; it reached weight of 5.3 ± 0.80 during the first ten days. The larvae were reared in floating cages. The daily growth was 1.94 mg during the 21 days of rearing. During this period it reached a weight of 48 mg and 23 mm in length.

REVIEW STUDY OF THE ARTIFICIAL BREEDING OF GATTAN (Barbus xanthopterus, HECKEL) IN IRAQ

This review article deals with the documentation of all the previous work on the propagation of Gattan. It was found that the induced spawning of Gattan is similar to that of common carp and Bunnei. The sensitive brooders needs a great care during handling and transportation. The brooders weight 5 were 1.5-10 kg for females and 1-2.5 kg for males, with age of 4-9 and 3-6 for the females and males respectively. The artificial breeding season continue from10 March till mid June. The MS222 was used for anesthesia with a concentration of 1/10000. Carp pituitary gland extract (CPG) was used in all the previous work, with different dosage wobbled between 3-6 mg/kg for females and 2-3 mg/kg for males. The total dosage was divided to 10 % for the first injection and 90 % for the second. The sex products was obtained after 12-14h from the second injection. The fertilized eggs were incubated in Zoug jars, at 23-25 ºC and water current of 0.5-0.7 l /min. The hatching was complete within three days. The larvae were reared in two stages the first in indoor incubators and the second in earthen ponds.

Using Osmotic Pumps to Induce the Production of Gametes in Male and Female European Eels.

Simple SummaryThe European eel is a species with high commercial value for aquaculture, and it has suffered a drastic reduction of its natural stocks during the last decades; thus, breeding in captivity is nowadays considered essential to avoid the extinction of the species. In this sense, a new method to maturate the European eel (males and females) for eel aquaculture has been studied. For the first time in the European eel, a controlled release hormone system (osmotic pumps) has been tested, which allowed to induce the testis maturation and sperm production in part of the males as well as a very early maturation and ovulation in the females.The European eel (Anguilla anguilla) is a commercially valued species for aquaculture. Over the past decades, it has experienced a drastic reduction in its natural stocks. Thus, breeding in captivity is considered essential, nowadays, to guarantee the eel aquaculture and to reduce pressure on natural populations. Traditionally, the European eel has been sexually matured by means of weekly hormonal injections, which cause stress to the fish. The purpose of this research study was to assess the use of osmotic pumps as a new method to induce sexual maturation in male and female European eels, without the weekly injection. The control groups were treated with weekly hormone injections (recombinant human chorionic gonadotropin for males and carp pituitary extract for females), and the implanted groups were treated with osmotic pumps (ALZET® osmotic pumps) loaded with the respective hormones. Regarding male European eels, this study shows that the use of controlled release systems was able to induce the maturation and spermiation, but without the necessary capacity to produce enough gametes with acceptable quality parameters that could meet the needs of a commercial eel hatchery. Concerning female European eels, the study demonstrates that the use of osmotic pumps loaded with CPE became an effective method, generating early maturations (4 to 10 weeks) in 50% of the females, so this method could become a viable alternative for eel hatchery procedures.

Effects of gonadotropin-releasing hormone agonist administered in microparticles on sperm quality and quantity, and plasma sex steroid levels in northern pike

Artificial reproduction of northern pike Esox lucius is impeded by the likelihood of obtaining only a small volume of sperm of inconsistent quality. A controlled-release hormone delivery system has the potential to enhance sperm production while avoiding multiple injections The objective of this study was to investigate the effects of mammalian gonadotropin-releasing hormone agonist (mGnRHa) incorporated into poly(lactic-co-glycolic acid) (PLGA) microparticles on milt production, spermatozoon characteristics, and secretion of 17β-estradiol (E2), 11-keto testosterone (11-KT), and testosterone in northern pike. Fish were divided into four groups and injected with 2 mg/kg BW carp pituitary extract (CPE), 20 µg/kg BW mGnRHa in PLGA microparticles, or 20 µg/kg BW mGnRHa plus 20 mg/kg BW metoclopramide (MET) in PLGA microparticles (PLGA + MET), along with a control group injected with 1 ml/kg 0.9% NaCl. At 48 h postinjection, the volume of milt produced was significantly greater in groups treated with CPE and PLGA + MET than in other groups. At 96 h postinjection, all hormone-treated groups exhibited significantly higher spermatozoon average velocity than recorded in the control group. Spermatozoon motility was significantly increased (P < 0.05) in the CPE and PLGA groups compared to baseline values. All treated groups showed significantly lower levels of 11-KT after the hormone injection compared to baseline values and to controls. Plasma testosterone levels increased in all hormone-treated groups. The use of PLGA microparticles, with or without metoclopramide, is suitable for use as a carrier of hormone treatments to regulate spermiation in mature northern pike.