Effect of hCG and Ovaprim™ on reproductive characteristics of male Levantine scraper, Capoeta damascina (Valenciennes, 1842)

Recovery and Characterization of Spermatozoa in a Neotropical, Terrestrial, Direct-Developing Riparian Frog (Craugastor evanesco) through Hormonal Stimulation

The Vanishing Rainfrog (Craugastor evanesco) is an endemic and critically endangered frog species of Panama. It is suspected that 90% of the population has disappeared from the wild. Frogs were collected from the wild and brought to a Captive Breeding Program; however, accomplishing regular reproductive events for this species has been difficult. The objective of this study was to determine the effect of hormonal stimulation on the production and quality of C. evanesco spermatozoa, aiming to develop an efficient and safe sperm collection protocol as a tool to help reproduce this endangered species. Mature males received intra-peritoneal injections with one of six hormone treatments, including des-Gly10, D-Ala6, Pro-NHEt9-GnRH-A, Amphiplex or hCG. Urine samples were collected at 10 different time points post-injection. Quality assessments included sperm concentration, percentage motility, percentage forward progressive motility (FPM), osmolality, pH and morphology analysis. Our results indicate that the optimal treatment for the collection of highly concentrated sperm samples of C. evanesco is 4 µg/gbw GnRH, followed by Amphiplex and 2 µg/gbw GnRH as sub-optimal treatments and finally, 6 µg/gbw GnRH and 5 and 10 IU/gbw hCG as non-optimal treatments. GnRH-A at 4 μg/gbw and Amphiplex stimulated the production of samples with the highest sperm concentrations and quality, despite Amphiplex producing lower percentages of intact acrosome and tail. In contrast, hCG concentrations were not reliable inducers of sperm production, consistently showing lower concentrations, higher percentages of sperm abnormalities and more acidic spermic urine than that induced by Amphiplex and GnRH-A. Morphological assessments revealed that C. evanesco spermatozoa have a filiform shape with a large acrosome on the anterior part of an elongated head, a small midpiece and a long tail with two filaments joined together by an undulating membrane.

A novel technique for mass induction of propagation in small fish species: Hormone immersion

Due to the lack of environmental stimuli found in their natural habitat, not all species of tiny fish can reproduce naturally in the conditions of captivity. Silver rasbora (Rasbora argyrotaenia) was used as the model organism in this study, which is the first to successfully use the hormonal technique of immersion to mass induce spawning and spermiation in small fish species. In this study, in order to find out the effect of immersion hormone treatment, two separate experiments in which commercial hormone Ovaprim™ was used for spawning induction and Ovagold™ for spermiation induction were conducted. Four doses of hormones (0.0 mL/L, 0.7 mL/L, 1.4 mL/L, and 2.1 mL/L) were evaluated on 24 females and 40 males in total. According to the experimental findings of female breeders, 1.4 mL/L dose of Ovaprim™ showed best results on latency period (8.67 h) with a total number of eggs (6994 egg) and fertilization rate (99.22 %). In addition, hatching and larval survival rate have also increased. Milt volume and sperm concentration have also seen an increase to 4.25 μL/g bw and 42.71 10⁶ cell/μL respectively at 2.1 mL/L hormone concentration. The best results or responses were obtained by immersion treatments using Ovaprim™ doses of 1.4 mL/L on female and Ovagold™ concentrations of 2.1 mL/L on male. This new technique is a beneficial for breeding small fish species for either commercial or conservational culture condition.

The Effect of Hormonal Treatment on Selected Sperm Quality Parameters and Sex Steroids in Tropical Cyprinid Bala Shark Balantiocheilos melanopterus

Hormone treatments are routinely employed with bala shark Balantiocheilos melanopterus male broodstock to stimulate the production of high-quality sperm. In the current trial, three spermiation-inducing treatments were evaluated: 20 μg/kg body weight (BW) recombinant hCG; 20 μg/kg BW [D-Ala6, Pro9, NEt]- gonadotropin-releasing hormone (GnRHa) with 20 mg/kg BW metoclopramide; and poly(lactic-co-glycolic acid) (PLGA) microparticles with slow release of 10 μg/kg BW GnRHa. A 0.9% saline AS negative control was also included. Administration of the GnRHa through the form of slow release of PLGA microparticles 24 h after treatment resulted in a significantly higher sperm volume, motility percentage, and total sperm count compared to the control. Injection of GnRHa with metoclopramide induced sperm parameters that did not differ from the control, with the exception of motility percentage. The lowest potency to induce spermiation in bala sharks was in the treatment with recombinant hCG. Both PLGA microparticles and GnRHa with metoclopramide significantly increased blood plasma concentrations of testosterone and 11-ketotestosterone compared to the control. The PLGA microparticle system with continuous release of 10 μg/kg BW GnRHa was the most effective treatment in inducing spermiation in bala sharks.

The relationship between semen seminal plasma ions and sperm cell velocities of wild-caught longspine scraper, Capoeta trutta

In this study, semen seminal plasma contents and the motility of sperm cells were determined in Capoeta trutta via a computer-assisted sperm analysis system. In addition, we evaluated the relationship between semen seminal plasma ions and the velocities of sperm cells. Although the predominant ions were K ( 206.84 ± 20.61  mg L- 1 ) and Na ( 128.06 ± 23.82  mg L- 1 ) in the semen seminal plasma, Ca ( 14.05 ± 4.13  mg L- 1 ) and Mg ( 3.35 ± 0.44  mg L- 1 ) were not predominate according to our results. However, partially strong relationships between the curvilinear velocity value (VCL) and K (R 2 = 0.67 ; p < 0.05 ) were found, while it was moderate with Mg (R 2 = 0.48 ; p < 0.05 ). There was a weak relationship with Na (R 2 = 0.17 ; p < 0.05 ) and Ca (R 2 = 0.34 ; p < 0.05 ). In our results, while the trace metals were determined as Zn > Al > B > Li > Cu in semen seminal plasma, they are not correlated with sperm cell velocities. Finally, we hope that the present information on the motility parameters of Capoeta trutta in this paper will eventually help artificial insemination in reproduction practices.

Induction of spermiation using Ovaprim™ with topical gill method in the silver rasbora (Rasbora argyrotaenia)

The main obstacles on silver rasbora (Rasbora argyrotaenia) culture are having the limited number of broodstock and spawning depending on the season. The purpose of this study was to determine the effect of different dosage of Ovaprim™ induction by topical gill method to silver rasbora spermiation in order to continue the production out of its reproduction season with an optimum dose. A total of 30 male fish with a weight of 7.78 ± 0.20 g and length 4.11 ± 0.31 cm was used in this research. Topical gill treatments of Ovaprim™ were administered with following doses; 0.15 μl/g, 0.25 μl/g, 0.35 μl/g, 0.45 μl/g and 0.55 μl/g body weight. Milt volume, sperm concentration, sperm motility, and sperm viability parameters were observed in this study to understand the optimum dose of Ovaprim™ for male silver rasbora breeders. Spermiation induction of silver rasbora using Ovaprim™ with topical gill method has been successfully carried out, indicating an increase (P < 0.05) in milt volume, sperm concentration, sperm motility, and sperm viability. According to results a dose of Ovaprim™ is recommended to be used the 0.25 μl/g body weight in the spermiation induction of silver rasbora.

Spawning performance, serum sex steroids, and ovarian histology in wild-caught Levantine scraper, Capoeta damascina (Valenciennes, 1842) treated with various doses of sGnRHa + domperidone

As global aquaculture continues to expand, increasing efforts are focusing on assisted reproductive technologies. This study sought to test whether salmon GnRH [D-Arg6, Pro9NEt]) analogue (sGnRHa) + domperidone injection at 0.25 mL/body weight (BW; 5-μg sGnRHa + 2.5-mg domperidone), 0.5 mL/kg BW (10-μg sGnRHa + 5-mg domperidone), or 1.0 mL/kg BW (20-μg sGnRHa + 10-mg domperidone) affects spawning performance and gamete quality in wild-caught Levantine scraper, Capoeta damascina. The ability of these treatments to elicit a response was further examined by in vivo stimulation of estradiol (E2) and 17α,20β-dihydroxy-4-pregnen-3-one (DHP) and by its in vivo potency to induce oocyte maturation (OM). Females that received saline injection (control) did not spawn, whereas sGnRHa + domperidone induced ovulation and spawning across the hormonal gradient. Spawning success was highest with the 0.5 mL/kg dosage (80%) and female latency period decreased with increasing dosage. Females treated with 0.5 mL/kg had a significantly higher fecundity than those injected with 0.25 or 1.0 mL/kg. Mean oocyte diameter significantly increased in females treated with 0.5 or 1.0 mL/kg. Fertilization success, hatching rate, larvae morphology, and survival were not affected by hormonal treatment. At 12 h postinjection, E2 levels significantly declined in females treated with 0.5 or 1.0 mL/kg, whereas DHP levels significantly increased across the hormonal gradient. This steroidogenic shift is supported by histological analyses, where OM was accelerated by administration of sGnRHa + domperidone in a dose-dependent manner. In conclusion, the 0.5 mL/kg dosage of sGnRHa + domperidone is recommended for assisted reproduction of Levantine scraper.