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21.
Although aquatic species cryopreservation protocols have been studied around the world over the past 60 yr., germplasm repository development efforts and commercialization have begun only recently. The goal of this project was to develop a self‐contained mobile laboratory for on‐site high‐throughput cryopreservation of aquatic species. The objectives of this study were to: (1) identify how a mobile laboratory would function in different operational scenarios, (2) customize an enclosed cargo trailer to function as a mobile laboratory, (3) evaluate the laboratory layout and ability of cryopreservation equipment to operate from generator power, and (4) document the investment costs for private and public groups to integrate a mobile laboratory into an existing cryopreservation facility at three levels of automation and estimate the total cost per trip based on hypothetical assumptions for two scenarios (aquaculture production and repository development). There were three operational designs identified for the mobile laboratory: (1) self‐contained work inside the unit using generator power, (2) work inside the unit using external facility power, and (3) using the equipment inside of a host facility. The investment costs for a base‐level mobile laboratory ranged between US$5670 and US$5787 for private groups and between US$5208 and US$5315 for public groups. With the addition of a range of automated processing equipment, total investment costs ranged from US$13,616 to US$103,529 for private groups and US$12,494 to US$94,891 for public groups. The total cost per trip to cryopreserve sperm of 59 blue catfish, Ictalurus furcatus, males to produce 6300 0.5‐mL French straws was estimated to range from US$6089 to US$14,633 for private and between US$5703 and US$16,938 for public groups depending on the level of automation. Total cost per trip to cryopreserve sperm of 500 males of five different species in the genus Xiphophorus to produce 641 0.25‐mL French straws was estimated to range from US$6653 to US$7640 for private and US$7582 to US$8088 for public groups depending on level of automation. Overall, a commercial‐scale mobile laboratory was developed that can assist current germplasm activities and support future repository and industry development, and the layout information provided can help others to design and build comparable units.  相似文献   
22.
This study documents early out-of-season induced spawning of channel catfish Ictalurus punctatus. During the early spring (February–April) of 1999, 2000 and 2001, ponds containing (1) male and female channel catfish (mixed-sex ponds) or (2) male channel and blue catfish I. furcatus only, or female channel catfish only (single-sex ponds) were heated to 24–30°C to encourage gonadal maturation and spawning. Unheated ponds were stocked with males and females and were monitored during the duration of heating. When natural spawning occurred in the heated ponds, the fish were captured by seining and unspawned females were injected with 100 μg kg−1 of synthetic leutenizing hormone-releasing hormone. Injected females were either paired with males or held in communal all-female groups, and monitored for ovulation. Eggs were collected and fertilized with sperm of channel catfish or blue catfish. Females paired with males were induced to spawn 44 days (mixed-sex ponds) and 50 days (single-sex ponds) before natural spawning occurred in unheated ponds. Spawning latency (the time between injection and ovulation) and the percentage of neurulated embryos from eggs fertilized using channel catfish sperm was not different between spawning before the natural season (P=0.68) and during the natural season in fish from mixed-sex ponds (P=0.57). Females held in all-female groups produced eggs 34 days before the onset of spawning in unheated ponds. Spawning latency was not different between spawns before and during the natural season (P=0.16), and the percentages of neurulated embryos from eggs fertilized with channel catfish sperm (P=0.76) or blue catfish sperm (P=0.77) before or during the natural season were not different. This study demonstrates the feasibility of conditioning of channel catfish females for early out-of-season induced spawning in the laboratory.  相似文献   
23.
Gynogenesis is a naturally occurring phenomenon in lower vertebrates in which offspring receive two sets of chromosomes from the female (Dawley 1989). This occurs when development is activated by sperm, but genetic material from the male is not incorporated into the embryo. Normally, haploid offspring result that do not survive to hatching, although in certain instances suppression of meiosis II or first mitosis can result in diploid gynogenetic offspring (Purdom 1993). Artificially induced gynogenesis has been used in the breeding and genetic study of several fishes, including salmonids (Chourrout 1982; Allendorf et al. 1986), tilapia (Don and Avtalion 1988), and channel catfish (Liu et al. 1992). Gynogenesis has been applied to production of monosex populations, isogenic populations, and inbred lines of fish (Ihssen et al. 1990; Tave 1993). Gynogenesis can be induced artificially by irradiating sperm with ultraviolet (UV) radiation to inactivate genetic material. Eggs are fertilized with the irradiated sperm and shocked by temperature or pressure change to restore diploidy.  相似文献   
24.
Abstract.— Only limited research has addressed the effect of salinity on hatching of channel catfish Ictalurus punctatus eggs, and no studies have evaluated the effect of salinity on fry development and survival. This study was undertaken to determine the effect of environmental sodium chloride (0, 1, 2, and 4 g/L. NaCl) on percent hatch, yolk utilization, and survival of channel catfish fry. Experiments were conducted in recirculating systems using seven egg masses (1–2 d old). Each egg mass was divided into smaller portions which remained undissociated or were dissociated with sodium sulfite (NaSO3). Eggs were incubated until hatching. Wet and dry weights were obtained for sacfry at 1 and 5 d post-hatch to determine wet weight gain and dry weight loss, and fry were sampled 7 d after initiation of exogenous feeding to determine survival. Percent hatch, yolk utilization, and survival of fry hatched from undissociated eggs were greatest at 1 g/L NaCl. In addition, treatment of eggs with NaSO3 significantly reduced percent hatch at all NaCl levels. Although our results indicate that addition of NaCI to hatchery water supplies can increase production of channel catfish fry, additional research is needed before this practice can be recommended on a commercial basis.  相似文献   
25.
To provide necessary standardization of procedures for cryopreservation of sperm, a spectrophotomeric method was developed to determine the sperm concentration of diploid and tetraploid Pacific oysters, Crassostrea gigas. Wavelengths of 380, 550, 581 and 780 nm were compared, and 550 and 581 nm were found to be the most sensitive and reliable. A linear relationship between sperm concentration and photometric absorbance was observed for sperm concentrations between 2 × 107 and 2 × 109 cells mL?1. The regression equation for the standard curve at 550 nm for sperm of diploid oysters was Y=?8.528+1.165 log X. The equation for sperm of tetraploid oysters was Y=?8.844+1.236 log X. The equation at 581 nm for sperm of diploid oysters was Y=?8.07+1.104 log X. The equation at 581 nm for sperm of tetraploid oysters was Y=?8.331+1.167 log X. Comparisons derived from the standard curves at 581 nm between observed values and the predicted values indicated good agreement for sperm from diploid (coefficient of determination, r2=0.983) and tetraploid (r2=0.980) oysters.  相似文献   
26.
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   
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