Toxicity of Protectants to Embryos of Silver Carp (Hypophthalmichthys molitrix) After Cold Storage at Different Storage Time Periods

The hatching success of silver carp (Hypophthalmichthys molitrix) embryos was examined after 12–24 h of storage at 4°C. The protectants used were propylene glycol (PG) (0.5, 1.0, 1.5, 2.0, 2.5, 3.0, and 3.5 M), sucrose (0.01, 0.1, 0.25, 0.5, 0.7, 0.9, and 1.0 M), and different concentrations of PG, with 0.25 M sucrose in each. Among all the sucrose concentrations tested alone, 0.25 M showed better hatching (39%) performance, whereas PG alone showed 35% hatching, and maximal (50%) hatching performance was found at 1.0 M PG in combination with 0.25 M of sucrose. The possible duration of the effective storage time period was 20 h with PG in addition to sucrose. No survival of preserved embryos was found when preserved in 3.0-M or in 3.5-M concentrations of PG, plus 0.9 M or 1.0 M concentrations of sucrose. Similarly, embryos failed to hatch when preserved with carbon-filtered ground water.