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1.
Black sea bass Centropristis striata L. are protogynous hermaphrodites that develop and spawn as females before changing sex to male. Since all fish eventually become males, determining the relationship between sperm production, sperm quality and seasonal changes in plasma levels of testosterone (T) and 11‐ketotestosterone (11‐KT) could be useful for identifying appropriate males to maintain as broodstock. Milt and blood samples were collected three times during an 8‐week spawning season. Milt volume (3.5±0.76 mL kg?1), sperm density (3.2 × 108± 0.31 cells mL?1), sperm production [11 × 108±3.4 cells kg?1 body weight (BW)] and sperm motility (80±0.6%) were at their highest during the first sampling interval and coincided with the highest 11‐KT levels (1.0± 0.11 ng mL?1). All of the sperm indices decreased to their lowest levels during the final 3 weeks of the study. Sperm viability was highly correlated (adjusted R2=0.84) with sperm motility. Sperm cryopreserved in modified Mounib's extender (MME) had the highest post‐thaw motility compared with two other extenders. Post‐thaw motility of sperm cryopreserved in MME was not different from fresh after 90 days of storage. There was no difference in fertilization rates between fresh (69±2.4%) and post‐thaw (67±4.1%) sperm samples taken from the same male or among males. These results demonstrate that the quality of black sea bass spermatozoa is higher earlier in the spawning season and that acceptable post‐thaw fertilization rates can be obtained from cryopreserved sperm.  相似文献   

2.
The summer flounder, Paralichthys dentatus L., is a high‐value species and considerable research has been conducted to determine practices conducive for its culture. As milt can be limited in this species, experiments were conducted to develop a practical sperm cryopreservation protocol for hatchery use. Two dilution ratios (1:2 and 1:4; sperm:extender), 2 diluents (saline and sucrose‐based), 2 cryoprotectants (10% DMSO and 12% glycerol) and 3 freezing rates (?5, ?10 and ?15°C min?1) were evaluated using differential staining to assess post‐thaw sperm survival. Seven combinations of the factors examined reduced post‐thaw viability by less than 30%. The average viability of sperm from fresh, pooled flounder milt (67.2 ± 2.9%) was not different from that of thawed milt diluted 1:4 with sucrose diluent (10% DMSO) frozen at ?5°C min?1 (38.4 ± 7.7%) and fertilization and hatch success were not different in trials using fresh or thawed, cryopreserved sperm. From these experiments a practical sperm cryopreservation method was developed, but further refinement of the freezing protocol is necessary to optimize results.  相似文献   

3.
Sperm cryopreservation is an essential tool for long‐term storage of genetic resources for aquaculture fishes. The goal of this study was to develop an efficient and streamlined protocol for high‐throughput processing for sperm cryopreservation in Atlantic salmon, Salmo salar. The objectives were to evaluate: (1) osmolality of blood serum for determining extender osmolality, (2) effects of extenders for fresh sperm dilution and refrigerated storage, (3) effects of methanol and dimethyl sulfoxide (DMSO) on fresh sperm motility, and (4) motility and fertility after thawing. In this study, sperm samples were collected at a hatchery site in Canada and shipped to a freezing site located 2200 miles (3550 km) away in the USA. Evaluation of three extenders indicated that Mounib solution was suitable for diluting dry sperm for sample processing. Ten percent of methanol or DMSO was less toxic to sperm cells than was 15% within 30 min. Further testing with methanol at 5, 10, and 15%, and sperm solution : extender dilutions (v:v) of 1:1, 1:3, and 1:19 (at concentrations of 5 × 107, 3 × 108, and 1 × 109 cells/mL) indicated that methanol at 5 and 10% showed less toxicity to fresh sperm within 1 h at sperm:extender dilutions of 1:1 and 1:3. Post‐thaw motility of sperm cryopreserved with 10% methanol was significantly higher than that with 10% DMSO, and fertility reflected those results (0–1% in DMSO vs. 38–55% in methanol). Further evaluation of sperm cryopreservation with 10 and 15% methanol at sperm dilution ratios of 1:1, 1:3, and 1:19 indicated that post‐thaw motility in 10% methanol was significantly higher than that in 15% methanol, and post‐thaw fertility in 10% methanol at 1:1 and 1:3 dilution ratios had fertilization rates similar to that of fresh sperm controls. Sperm samples from 12 males cryopreserved with 10% methanol showed male‐to‐male variation in post‐thaw motility (0–36%). Overall, a simplified standard protocol was established for cryopreservation of shipped sperm of Atlantic salmon using extender without egg yolk and yielded satisfactory post‐thaw motility and fertilization rates. This procedure can be readily adopted by aquaculture facilities to take advantage of high‐throughput cryopreservation capabilities at remote service centers. Most importantly, this approach lays the groundwork for an alternative commercial model for commercial‐scale production, quality control, and development of industrial standards. Control of male variability and sperm quality remain important considerations for future work.  相似文献   

4.
Our goal was to develop a standardized approach for sperm vitrification of marine fish that can be applied generally in aquatic species. The objectives were to: (i) estimate acute toxicity of cryoprotectants over a range of concentrations; (ii) evaluate the properties of vitrification solutions (VS); (iii) evaluate different thawing solutions and (iv) evaluate sperm quality after thawing by examination of motility and membrane integrity. Sperm were collected from red snapper (Lutjanus campechanus), spotted seatrout (Cynoscion nebulosus) and red drum (Sciaenops ocellatus). A total of 29 combinations of cryoprotectants were evaluated for toxicity and glass formation. Samples were loaded onto 10‐μL polystyrene loops and plunged into liquid nitrogen. There was a significant difference (P < 0.05) in post‐thaw motility among VS and among species when using the same VS. The sperm in VS of 15% DMSO + 15% ethylene glycol + 10% glycerol + 1% X‐1000? + 1% Z‐1000? had an average post‐thaw motility of 58% and membrane integrity of 19% for spotted seatrout, 38% and 9% for red snapper, and 30% and 19% for red drum. Adaptations by marine fish to higher osmotic pressures could explain the survival in the high cryoprotectant concentrations. Vitrification offers an alternative to conventional cryopreservation.  相似文献   

5.
In two trials, Arctic char (Salvelinus alpinus) semen was frozen in 0.5 mL straws using extenders consisting of 0.3 M glucose and 10%, 12.5% or 15% methanol. Cryopreserved semen was thawed by immersing straws in 25 °C water for 17 s (11.6 °C s?1) or in 5 °C water for 60 s (3.3 °C s?1). The viability of the frozen–thawed semen was measured by determining post‐thaw motility and sperm membrane integrity. Two fertility trials were also conducted. There was no effect of trial or thaw rate on post‐thaw sperm viability or fertility. Use of 15% methanol in the extender resulted in the highest overall percentage of sperm motility and fertility. Use of 12.5% methanol as a cryoprotectant resulted in a higher per cent post‐thaw motility and a lower percentage of dead cells than did 10% methanol. Thus, levels of methanol higher than the commonly used 10% are beneficial for cryopreserving Arctic char sperm.  相似文献   

6.
This study reports on the spermatological properties, and on the development of a protocol for refrigerator storage (4°C) of Labeo calbasu (Hamilton, 1822) sperm for artificial breeding. Volume, motility, concentration and pH of the freshly collected sperm were 2.21 ± 0.53 (μL g?1 of fish weight) (mean ± SD), 95 ± 1 (%), 1.93 ± 0.44 × 109 (cells mL?1) and 7.56 ± 0.17 respectively. Sperm activation was evaluated at different osmolalities of NaCl solution, and motility ceased completely when osmolality of the extender was ≥287 mOsmol kg?1. Sperm retained motility for 24, 72 and 108 h, after refrigerator storage when sperm were undiluted, suspended in Alsever's solution and suspended in Alsever's solution containing 5% methanol respectively. Fertilization rate of fresh eggs with sperm stored at 4°C in Alsever's solution and Alsever's solution containing 5% methanol was 77% and 60% with a hatching rate of 60% and 43% respectively. The fertilization and hatching success of the stored sperm suggests potential to use refrigeration for transporting genetic material to hatcheries for artificial breeding of L. calbasu in Bangladesh.  相似文献   

7.
Effectiveness and efficiency of frozen sperm on fertilization and hatching success of eggs from silver barb was examined in relation to cryoprotectants, freezing rate and storage period. Sperm was diluted in calcium‐free Hank's balanced salt solution, equilibrated with dimethylsulphoxide (DMSO), propylene glycol, sucrose or methanol at 5%, 10%, 15% or 20% final concentrations, and frozen in 250‐μL straws using a one‐step freezing procedure (1, 5 and 8°C min?1 from 25 to ?40°C). Highest post‐thaw sperm motility was found from a treatment using 10% DMSO and 5°C min?1 (82.2 ± 2.1%), similar to that of 10% DMSO and 8°C min?1 (87.8 ± 3.2%). Post‐thaw motility of sperm frozen at 5 or 8°C min?1 was significantly higher than 1°C min?1. Relative sperm motility declined significantly after 10 months of cryostorage while viability did not change during a 12‐month cryostorage. Average fertilization rates of sperm after 1 and 4 months of storage were 64.5 ± 4.6% and 61.3 ± 3.4%, respectively, similar to those of fresh sperm (69.6–72.3%). Hatching rates of cryopreserved sperm (45.4–51.2%) were similar to those of fresh sperm (51.8–57.8%). This study developed suitable methods for cryopreservation of silver barb sperm that can be used to facilitate hatchery operation.  相似文献   

8.
The outer coat of embryo of Stenopus hispidus may affect cryoprotectant penetration and post‐thaw procedures during cryopreservation studies. The mechanical method for separating embryos of S. hispidus was exhausting and time consuming. The aim of the present study was to compare the effect of different enzymatic isolation techniques to achieve the individual separation of embryos. Embryo clusters were exposed to three enzymes (trypsin, collagenase and hyaluronidase) at different concentrations (0.2–1.6 mg mL?1) for different treatment times (5–20 min). Morphological appearance and hatching competence of the embryos separated mechanically and enzymatically were assessed. The optimum conditions for the three enzymes were 10 min 0.4 mg mL?1 trypsin, 10 min 0.8 mg mL?1 collagenase and 10 min 0.8 mg mL?1 hyalruonidase and embryo hatching percentages were 43.8 ± 4.2%, 39.9 ± 4.9% and 42.2 ± 3.5% respectively. The enzymatic isolation technique does not affect either morphological appearance or hatching competence of the separated embryos. The method developed in this study will be helpful for future cryopreservation studies on S. hispidus embryos.  相似文献   

9.
This study investigated factors key to the development of sperm cryopreservation in the greenlip abalone Haliotis laevigata using a programmable freezing technique, including (1) permeable cryoprotectant agent (CPA) selection; (2) cooling rate; (3) endpoint temperature; (4) thawing temperature; (5) sperm to egg ratio and (6) sugar, vitamin and amino acid supplementation, using sperm motility, fertilization rate, plasma membrane integrity, mitochondrial membrane potential or acrosome integrity as quality assessment indicators. Results showed that among the permeable CPAs evaluated, 10% dimethyl sulfoxide was the most suitable for greenlip abalone sperm cryopreservation. The highest post‐thaw sperm motility was achieved with the sperm being frozen at a cooling rate of ?5°C min?1 to ?30°C from 0°C and thawed and recovered in 40°C and 18°C seawater baths respectively. The addition of sugars in 10% dimethyl sulfoxide did not significantly improve the post‐thaw sperm motility and fertilization rate. The addition of 0.6% glycine, 0.2% taurine or 0.02% L‐ascorbic acid, on the other hand, significantly improved the post‐thaw sperm motility. However, only the addition of 0.6% glycine improved the post‐thaw sperm fertilization rate, which was further confirmed by the improvement of the post‐thaw sperm mitochondrial membrane potential and acrosome integrity through flow cytometry analysis.  相似文献   

10.
Experiments were performed to improve protocols for sperm cryopreservation of paddlefish (Polyodon spathula), a species for which there has been limited study. The first experiment was conducted to investigate the effects of two extenders (modified Tsvetkova’s extender: mT and modified Hanks’ balanced salt solution: mHBSS) in combination with methanol (MeOH) and dimethyl sulfoxide in two concentrations (5 and 10%) on the postthaw motility and fertilization rates of cryopreserved sperm. The highest postthaw motility (85 ± 5%) was observed when sperm were frozen using mT extender with 10% MeOH as cryoprotectant. Extenders (P = 0.0018) and cryoprotectants (P = 0.0040) each had a significant effect on the postthaw motility of paddlefish sperm. The highest fertilization (80 ± 3%) was found when eggs were fertilized with sperm frozen with mT extender in combination with 10% MeOH. However, there was no significant difference among fertilization rates when MeOH was used as a cryoprotectant in either concentration or in combination with either mT or mHBSS extenders. In the second experiment, 4000 eggs were fertilized with the pooled contents of five straws of thawed sperm (total volume of 1.25 mL) using mT extender in combination with 5% MeOH, and hatch rates as high as 79 ± 5% were observed. A third experiment was also conducted to clarify the role of MeOH concentration; however, no significant difference was found among fertilization and hatch rates when either 5 or 10% MeOH was used as a cryoprotectant. These results suggest that MeOH is a safe and reliable cryoprotectant for freezing of paddlefish sperm and obtaining viable postthaw sperm for consistent fertilization and hatch rates. Further, this experimental protocol is relatively simple and applicable for commercial hatchery production of paddlefish.  相似文献   

11.
Crappie, Pomoxis spp., are popular game fish throughout North America and are produced by public and private hatcheries. However, production is limited by a lack of information on tank culture and induced spawning methods. Development of techniques for storage of sperm and in vitro fertilization would increase flexibility in spawning. Therefore, techniques for sperm cryopreservation were examined in white crappie, Pomoxis annularis. Sperm from adult wild white crappie were used to evaluate sperm extender, cryoprotectant agent and concentration, and cooling technique based on post‐thaw sperm motility. Percent egg fertilization was also compared between sperm stored in the two best cryopreservation protocols and two different osmotic activator solutions. Sperm were cryopreserved using treatment combinations of two extenders (350 mOsmol/kg Hanks' balanced salt solution [HBSS] and 350 mOsmol/kg Ca2+free HBSS) and two cryoprotectants (dimethyl sulfoxide [DMSO] and methanol) at concentrations of 5, 10, and 15% that were cooled at four different rates: 5, 10, 20, and 40 C/min. Post‐thaw sperm motility and fertilization rates indicated white crappie sperm can be cryopreserved using either extender, cryoprotectants of either 5% DMSO or 10% methanol, and cooling at 40 C/min. A follow‐up experiment demonstrated sperm in suspensions on ice retained viability after overnight transport.  相似文献   

12.
Sperm were collected in Florida from wild common snook, Centropomus undecimalis (Bloch), and were shipped to Louisiana State University for analysis and cryopreservation. Threshold activation of sperm (10% motility) occurred at 370 mOsmol kg?1, and complete activation occurred at 680 mOsmol kg?1. These values were significantly different. Sperm samples stored at 1°C in Hanks' balanced salt solution (HBSS) or in 0.6% NaCl solution at 200 mOsmol kg?1 retained motility for as long as 22 days. Mean motility remained above 50% for 9 days for sperm stored in HBSS and for 7 days for sperm stored in NaCl solution. Sperm exposed to 5% dimethyl acetamide (62±10%; mean±SD), 10% dimethyl sulphoxide (DMSO) (39±16%), 5% glycerol (26±5%) or 10% glycerol (6±2%) for 30 min had significantly lower motility than did unexposed sperm (89±9%). When used as a cryoprotectant, samples frozen with 5% or 10% DMSO or 5% methanol had significantly higher post‐thaw motility than did samples frozen with other cryoprotectants. Sperm cryopreserved with 10% DMSO (38±12%) had significantly higher post‐thaw motility than did sperm cryopreserved with 15% DMSO (19±10%) or 20% DMSO (4±4%). There were no significant differences in hatch rates of eggs fertilized with fresh sperm (54±29%) or cryopreserved sperm (41±35%). Survival to first feeding was not different between fish produced with fresh sperm (37±30%; range, 0–86%) or with thawed sperm (24±29%; 0–77%). Transport of sperm to a cryopreservation laboratory and back to a hatchery for thawing and use enabled collaboration between groups with specific expertise and provides a model for the application of cryopreservation by transport of fresh and frozen samples.  相似文献   

13.
The effects of extender composition and freezing rate on motility and fertility of frozen‐thawed Arctic char, Salvelinus alpinus, spermatozoa were investigated. Three freezing rates, two semen diluents and three cryoprotectants were tested. Semen frozen in 0.3 mol L?1 glucose diluent with 10% methanol as a cryoprotectant or in a diluent described by Lahnsteiner with 10%N,N‐dimethylacetamide (DMA) resulted in the highest sperm motility. Fertility was the highest for semen frozen in a glucose–methanol extender but was not significantly different than that for semen frozen in Lahnsteiner's diluent with 10% DMA. Dimethyl sulphoxide (DMSO) at 10% was a relatively ineffective cryoprotectant with either semen diluent. Semen frozen at 6 cm above the surface of liquid nitrogen resulted in a higher post‐thaw sperm motility and fertility than semen frozen at 5 cm. The addition of 7% fresh egg yolk to glucose diluent containing methanol or DMSO did not improve the fertility of frozen‐thawed spermatozoa. However, the addition of 7% fresh egg yolk to glucose–DMA extender significantly improved the fertilization percentages of frozen‐thawed spermatozoa. In conclusion, dilution of semen 1:3 in 0.3 mol L?1 glucose with 10% methanol and freezing 6 cm above the surface of liquid nitrogen (freezing rate of 40±8°C min?1, mean±SD from ?5 to ?55°C) is a promising protocol for cryopreservation of Arctic char semen.  相似文献   

14.
Experiments were carried out to develop an optimal cryopreservation protocol for tench sperm by testing the fertilizing capacity and motility parameters including progressive motility, curvilinear velocity (VCL) and linearity (LIN) of cryopreserved sperm. Three experiments were designed to this aim: first experiment where we tested the effects of two extenders (sugar‐based Grayling and ion‐based Kurokura 180) and two cryoprotectants (DMSO and methanol) on fertilization and hatching success; second where we tested the effect of cryoprotectant type (methanol or DMSO) in different concentrations (5%, 10% and 15%) on fertilization and hatching success; and third where we tested the effect of two cryoprotectants (methanol and DMSO) on sperm motility parameters (progressive motility, VCL and LIN) after 4 h post‐thaw storage (4°C). Sperm prepared with the sugar‐based Grayling extender displayed better fertilization and hatching rates independently of the applied cryoprotectant most likely due to glucose present which acted as an external cryoprotectant. Concerning cryoprotectant concentrations, the use of 10% methanol yielded the highest fertilization (85 ± 15%) and hatching (80 ± 13%) rates, which were significantly higher than in all other groups. During the post‐thaw storage time, 5% methanol, 10% methanol and 5% DMSO groups had significantly higher motility parameters than other groups and we observed no significant decline in any of the parameters during the storage time. Overall, we found that a sugar‐based extender in combination with methanol as cryoprotectant is suitable for the cryopreservation of tench sperm and allows storage of cryopreserved sperm for up to 4 h post thaw.  相似文献   

15.
Three cryoprotectants (dimethyl sulphoxide, propylene glycol and glycerol) and two diluents (sucrose based and saline based) were mixed (9 parts diluent–1 part cryoprotectant) factorially to produce six extenders that were tested to develop an effective sperm cryopreservation protocol for winter flounder Pseudopleuronectes americanus (Walbaum). Sperm were diluted 1:3 with each extender and frozen by flotation on liquid nitrogen before being submerged and stored for 30 days. Sperm left unfrozen in each extender for 20 min showed no toxic effects on motility. Extenders containing propylene glycol (PG) as cryoprotectant yielded higher post‐thaw sperm motilities than those containing dimethyl sulphoxide (DMSO) or glycerol. The sucrose‐based diluent performed better than the saline‐based diluent when DMSO was used as cryoprotectant, but there were no differences in post‐thaw motility between diluents for the other cryoprotectants. Activating sperm with ovarian fluid and sea water instead of sea water alone had no effect on post‐thaw motility. In fertilization trials, no differences were observed between any of the extenders and fresh milt when milt, eggs and sea water were left in contact for 1 h. When sperm were forced to compete for eggs by reducing contact time to 20 s, fertilization results followed those of sperm motility rates. Percentage hatch and morphology of larvae at hatching did not differ for eggs fertilized by cryopreserved and fresh sperm. This study represents the first reported successful attempt at cryopreserving winter flounder sperm and should improve gamete and broodstock management protocols for this species.  相似文献   

16.
The Southern flounder, Paralichthys lethostigma, is a valuable aquaculture fish with established markets in the USA. All‐female production in this species is an important technology for aquaculture because the females usually have body sizes twice those of males at the same age, and sex‐reversed males (genotypic XX neomales) are used for all‐female production by crossing with genetically normal females. However, sperm volume from the neomales is usually small (<0.5 mL) and limits their application for all‐female fish production. Cryopreservation of sperm from these sex‐reversed neomales will provide access on demand with increased efficiency to extend the application of neomales. The goal of this study was to develop a protocol for cryopreservation of sperm from the Southern flounder by using an automated high‐throughput processing system. The objectives were to: (1) determine the effect of osmolality on activation of sperm motility; (2) evaluate the effect of extender solutions on sperm motility capacity; (3) evaluate the acute toxicity of cryoprotectants (dimethyl sulfoxide [DMSO], propylene glycol, and polyethylene glycol) on sperm motility, and (4) estimate the effect of cooling rate on sperm cryopreservation and post‐thaw fertilization. Sperm motility was activated when osmolality was 400 mOsmol/kg or higher. Of the three extender buffers tested, HEPES4‐(2‐hydroxyethyl)‐1‐piperazineethanesulfonic acid (HEPES) at 300 mOsmol/kg resulted in better protection for sperm motility than did Hanks' balanced salt solution and Mounib solution at 300 mOsmol/kg during 7 d of refrigerated storage. After 30 min equilibration with the cryoprotectant of 15% DMSO, sperm motility was 24 ± 21% (fresh sperm motility without any cryoprotectants was 42%). After cooling at a rate of 20 C/min, post‐thaw sperm motility was 8 ± 5% and fertilization was 63 ± 40% evaluated at the 32–64 cell stage (5 × 105 sperm per egg). Overall, a protocol was developed for sperm cryopreservation in the Southern flounder with high‐throughput processing, which provides a tool to preserve the valuable genetic resources from neomale flounders, and enables germplasm repository development for the Southern flounder.  相似文献   

17.
This study developed a technique of sperm cryopreservation using liquid nitrogen (LN) vapour in farmed blacklip abalone Haliotis rubra through evaluating the following five key factors: (1) cryoprotectant agent (CPA) toxicity; (2) cooling temperature; (3) thawing temperature; (4) sperm to egg ratio and (5) sugar addition, using sperm motility or fertilization rate as quality assessment indicators. The results demonstrated that 6% dimethyl sulfoxide (DMSO) was the best single CPA for sperm cryopreservation in this species. The highest post‐thaw sperm motility was achieved when sperm were exposed to LN vapour for 10 min at 5.2 cm above the LN surface and thawed at 60°C and recovered at 16°C in seawater baths. Post‐thaw sperm motility was found to be significantly higher when 6% DMSO was used in combination with 1% or 2% glucose than 6% DMSO alone. Further evaluation of fertilization rate between these CPAs showed that 6% DMSO+2% glucose achieved the highest fertilization rate of 70% at a sperm to egg ratio of 10 000:1.  相似文献   

18.
For the first time was characterized the semen of Pimelodus britskii, hormonally induced and non‐induced induced, during the reproductive period. The experiment 1 was conducted with 12 fish per month, divided into: (i) induced with Carp Pituitary Extract (CPE), and (ii) without hormonal induction (testes macerated). The experiment 2 was conducted, with 30 fish, divided into groups for comparison of different doses of CPE and human Chorionic Gonadotrophin (hCG; T1: control; T2: 3.0 mg kg?1 CPE; T3: 0.5 mg kg + 3.0 mg kg?1 CPE; T4: 0.5 mg kg?1 + 7.0 mg kg?1 CPE; T5: 200 UI kg?1 hCG), the same fish were used every month, and the semen was collected by abdominal massage. In both, experiments were assessed the sperm motility and velocity by means of the CASA software. In experiment 1, the concentration of spermatozoids was significantly increase by application of CPE compared untreated males. The volume and motility decreased gradually until the end of the experiment, the highest values were recorded for treatment induced (0.49 ± 0.25 mL and 62.18, respectively). The same occurred to Gonadosomatic Index, showing the smallest value at the end of the reproductive period. The fish from experiment 2 released reduced volume of watery semen (0.1 mL). The values of sperm concentration, motility velocity decreased gradually throughout the months. For P. britskii, the reproductive period influenced the production and sperm quality. Despite small seminal volume released the dose of 7.5 mg kg?1 of CPE proved effective.  相似文献   

19.
Glucose, when measured in haemolymph, has been found to reflect a useful predictor of energetic investment. This study evaluated the pattern of glucose in the haemolymph, with an attempt to gain a better insight into the role of glucose as nutritional source of ovarian development and energy reserves during reproductive and non‐reproductive moulting cycles. The haemolymph of female giant freshwater prawn, Macrobrachium rosenbergii, was obtained at eight different moulting stages, and levels of glucose were determined using an enzymatic colorimetric glucose‐oxidase method in parallel with a histological examination of ovarian development. Glucose levels were relatively low (0.15 ± 0.02 mg mL?1) at D0 stage, an abrupt increase (0.52 ± 0.13 mg mL?1) during premoult D1 stage and declined (0.32 ± 0.10 and 0.31 ± 0.09 mg mL?1) during premoult D2 and D3 stages, respectively; thereafter, a slight increase (0.43 ± 0.09 mg mL?1) occurred at post‐moult A stage. The progression of ovarian growth, marked by an increasing gonadosomatic index (GSI) pattern during the reproductive moulting cycle (C0–D3 stages), was directly proportionate to fluctuations in glucose levels. GSI was significantly positively correlated with glucose (R = 0.40; P < 0.05). In contrast, glucose was notably higher at post‐moult A and premoult D2 stages during non‐reproductive moulting cycle, the period during which glucose is crucial for exoskeletal chitin synthesis. At this particular stage, a negative correlation between body weight and glucose (R = ?0.36; P < 0.05) was observed. The dynamics of glucose in the haemolymph of female M. rosenbergii correlated with ovarian growth, which signify that glucose as nutritional source for vitellogenesis, and affects the body weight of this species.  相似文献   

20.
We developed a simple dry shipper method for cryopreserving the sperm of Scombridae fish in outdoor environments. First, we undertook a preliminary study to optimize the sperm cryopreservation conditions using bullet tuna, Auxis rochei (Risso, 1810) sperm. We found that the optimum cryomedium contained 90% foetal bovine serum (FBS) or 300 mM trehalose as an external cryoprotectant and 10% dimethyl sulfoxide (DMSO) as an internal cryoprotectant. Under these optimized conditions, the post‐thaw sperm had a duration of motility of 500 s and a motility rate of >70%. We then performed practical trials of the optimized protocol in various outdoor environments (e.g., fishing boats and ports) using the sperm of five Scombridae species: chub mackerel, Scomber japonicus (Houttuyn, 1782); blue mackerel, S. australasicus (Cuvier, 1832); skipjack tuna, Katsuwonus pelamis (Linnaeus, 1758); longtail tuna Thunnus tonggol, (Bleeker, 1851) and Pacific bluefin tuna, T. orientalis (Temminck & Schlegel, 1844). The post‐thaw sperm of all five of these species had a duration of motility of 650 s and a motility rate of >70%, indicating that this simple method can be used to obtain high‐quality cryopreserved sperm of various Scombridae species in outdoor environments.  相似文献   

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