Cryopreservation of dorada semen (Brycon sinuensis) with different cryoprotectants at two percentages of inclusion

Abstract

Cryopreservation allows the conservation of genetic resources of fish in danger of extinction and improves reproductive processes in captivity. This research aimed to evaluate semen from dorada with three cryoprotectants at two inclusion
percentages. Spermation phase breeding males (n=12) were used, induced with 5 mg of carp pituitary extract/Kg. Six hours later, fresh semen (SF) was collected and diluted in cryoprotectant solutions composed of glucose 6%, egg yolk 12% and the
cryoprotectants dimethylsulfoxide (DMSO), dimethylacetamide (DMA) and ethylene glycol (EG) at inclusion percentages of 5 and 10%; then packed in 0.5 mL straws and frozen with nitrogen vapors. The semen was thawed fifteen days later in a serological bath. The quality of the FS, pre-frozen (PS) and thawed (TS) was evaluated with the support of the SCA® software (Sperm Class Analyzer). Total motility (Mt), types of motility, velocities, total progressivity and sperm concentration were evaluated. Damage to the sperm membrane (D-Mem), mitochondria (D-Mit) and DNA fragmentation (F-DNA) were measured by flow cytometry in TS. The Mt of SF was 97.0±7.0%, in SP it was 82.5±17.9% and in SD it was 45.413.6%, being higher when treated with DMSO10% (p <0.05). In TS, the D-Mem ranged from 62.1±18.8% (DMA 5%) to 49.89.8% (DMSO 5%), the D-Mit from 59.4±14.8% (DMA 5%) to 83.4±4.2% (DMSO 10%) and F-DNA between 9.5±14.0% (EG10%) and 1.6±0.2% (DMA10%) (p>0.05). The results allow us to infer that the evaluated cryoprotectants, including 5 and 10%, are a viable alternative for
the cryopreservation of dorada sperm.