Publications (7) View all
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Article: Motility of Colossoma macropomum cooled semen with different concentration of extenders
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ABSTRACT: The conservation of semen may have its costs reduced when used within a certain period of time through cooling techniques. These techniques are alternatives to reproductive management in fish farms, optimizing fertilization of oocytes and ensuring satisfactory reproduction. The quality of the extenders is essential, since it guarantees the maintenance of sperm cells. The tambaqui (Colossoma macropomum) is an endemic species from Brazil and reared in tropical regions throughout the world. Its supply chain is trending upward and production technologies are being improved, both by governmental programs and private initiative, as is the case of fish farms such as Delicious Fish in the state of Mato Grosso, Brazil, where this study was carried out. Different concentrations of cryoprotectants added in the extenders were tested during cooling of fresh semen of C. macropomum, and their motility was analyzed. Six males with secondary reproductive attributes of Neotropical migratory species were selected, weighed and hormonally induced. After stripping the semen through anteroposterior massage, a pool of semen from all the animals was constituted. The extenders tested were: T1: BTS (Beltsville Thawing Solution); T2: BTS + 1% Me2SO (dimethyl sulfoxide); T3: BTS + 2.5% Me2SO; T4: BTS + 5% Me2SO; T5: BTS + 8% Me2SO; T6: BTS + 1% Me2NCHO (dimethylformamide); T7: BTS + 2.5% Me2NCHO; T8: BTS + 5% Me2NCHO; T9: BTS + 8% Me2NCHO e T10: cooled pure semen. The progressive motility (PM%) of the samples was analyzed. After the analyses, the pool of semen was kept in eppendorfs, one for each analysis per day, and stored in refrigeration at 4 ± 1 °C. The seminal parameters were evaluated every 24 h to observe sperm viability. The statistic analyses were performed using the STATISTICA software. The motility of the semen “in natura” for each treatment was 95%, 88%, 78%, 85%, 67%, 72%, 60%, 57%, 47%, 83%, for the treatments T1, T2, T3, T4, T5, T6, T7, T8, T9 and T10, respectively. The progressive motility rate gradually decreased over time, varying according to the extenders. After four days the motility was 32% (T1), 33% (T2), 37% (T3), 27% (T4), 12% (T5), 38% (T6), 30% (T7), 22% (T8), 8% (T9) e 12% (T10). The increase in concentration of both internal cryoprotectants showed no significant difference for the treatments, except for T9, at 5% of significance (p < 0.05). The use of BTS without internal cryoprotectant did not reduce the efficiency of preservation of semen. However, the increase in the concentration of internal cryoprotectant has demonstrated a reduced percentage rate, particularly at concentrations of 8%. According to the extenders used, BTS + 1% of Me2NCHO presented the best sperm motility.Cryobiology 12/2012; 65(3):361. · 2.06 Impact Factor -
Article: Injuries in pacu embryos (Piaractus mesopotamicus) after freezing and thawing.
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ABSTRACT: Summary Although the sperm cryopreservation of freshwater and marine teleosts has been feasible for years, the cryopreservation of some fish embryos still remains elusive. Thus, the objective of this experiment was to analyze the embryo morphology after freezing and thawing 40 embryos of Piaractus mesopotamicus immersed into methanol and ethylene glycol, both at 7, 10 and 13% plus 0.1 M sucrose for 10 min. Soon after thawing, three embryos were treated with historesin, stained with hematoxylin-eosin and analyzed under an optical microscope. From every treatment, one palette containing embryos was thawed and incubated, but none of the eggs hatched. Samples containing two embryos were immersed into 10% methanol or 10% ethylene glycol both in association with sucrose, and embryos immersed into only water or sucrose solution were frozen, processed and analyzed using scanning electron microscopy (SEM). In both cases, the control group was immersed into only water. Although the embryos had the chorion, vitello, yolk syncytial layer and blastoderm, all of them were found altered under the optical microscope and by SEM. The chorion was irregular and injured; there was no individuality in the yolk granules; the yolk syncytial layer had an irregular shape, thickness and size; the blastoderm showed injuries in the nucleus shape and sometimes was absent; the blastoderm was located in atypical areas and absent in some embryos. In conclusion, no treatment was effective in preserving the embryos, and none of the embryos avoided injury from intracellular ice formation. These morphological injuries during the freezing process made the P. mesopotamicus embryos unfeasible for hatching.Zygote 07/2012; · 1.17 Impact Factor -
Article: INCREASING STORAGE CAPABILITY OF PACU (Piaractus mesopotamicus) EMBRYOS BY CHILLING: DEVELOPMENT OF A USEFUL METHODOLOGY FOR HATCHERIES MANAGEMENT
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ABSTRACT: Cryopreservation of fish gametes has been studied extensively in the last few decades, but the successful cryopreservation of fish embryos remains elusive. However, recent studies using short-term chilling techniques have shown that it is possible to store embryos at low temperatures with no significant loss in viability. Information on cryopreservation of Neotropical freshwater fish embryos has so far been very limited in the literature. In the present study, chilling protocols for storage of pacu embryos at - 8°C for up to 24 h were studied using different concentrations of sucrose in methanol. Embryos tolerated the subzero temperature for up to 6 h with no adverse effects (P > 0.05). After 12 h chilling, hatching rate of 64.0 ± 3.5% was recorded. Low temperature storage of pacu embryos by chilling is detailed here for the first time. Further studies are needed to extend the storage time and to improve the hatching rate.Cryo letters 04/2012; 33(2):125-133. · 1.25 Impact Factor -
Article: Chilling curves for Piaractus mesopotamicus (Holmberg, 1887) embryos stored at -8°C.
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ABSTRACT: SummaryThe present study investigates the effect of different slow chilling curves on the storage of pacu (Piaractus mesopotamicus) embryos submitted to chilling at -8°C. Embryos at the blastopore closure stage were divided into two groups: G1 - embryos exposed to cryoprotectant solution containing methanol (10%) and sucrose (0.5 M), treated as follows: (T1) taken directly from room temperature to the refrigerator without being submitted to the curve; (T2) chilling curve of 0.5°C/min; and (T3) chilling curve of 1°C/min; and G2 - the cryoprotectant solution alone was submitted to these same temperatures, receiving the embryos only after temperature had decreased, corresponding to treatments T4, T5 and T6, respectively. Treatments were kept at -8°C for a period of 6 h. Embryo development was evaluated for each treatment, with six replicates in an entirely randomized design. Survival among embryos not submitted to refrigeration was 94.3 ± 8.05%. Percentage of total larvae (TL) and addled eggs (AE) did not differ statistically between the groups, although percentage of swimming larvae (SL) exhibited higher values in G1 for the 1°C/min curve. Furthermore, when comparing the three chilling curves, a decrease of 1°C/min resulted in the highest TL percentage (90.85%), followed by the 0.5°C/min curve (78.52%). Thus, the use of 1°C/min chilling curves is recommended for P. mesopotamicus embryos stored for 6 h at -8°C.Zygote 03/2012; · 1.17 Impact Factor -
Article: Increasing storage capability of pacu (Piaractus mesopotamicus) embryos by chilling: Development of a useful methodology for hatcheries management.
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ABSTRACT: Cryopreservation of fish gametes has been studied extensively in the last few decades, but the successful cryopreservation of fish embryos remains elusive. However, recent studies using short-term chilling techniques have shown that it is possible to store embryos at low temperatures with no significant loss in viability. Information on cryopreservation of Neotropical freshwater fish embryos has so far been very limited in the literature. In the present study, chilling protocols for storage of pacu embryos at -8°C for up to 24 h were studied using different concentrations of sucrose in methanol. Embryos tolerated the subzero temperature for up to 6 h with no adverse effects (P >0.05). After 12 h chilling, hatching rate of 64.0 ± 3.5% was recorded. Low temperature storage of pacu embryos by chilling is detailed here for the first time. Further studies are needed to extend the storage time and to improve the hatching rate.Cryo letters 01/2012; 33(2):125-133. · 1.25 Impact Factor
