Ontogenetic variability of chill tolerance in larval Artemia salina: I. Single type cryoprotectants

Abstract

Chill tolerance was determined for various larval stages of Artemia salina with and without the addition of single cryoprotective agents (glycerol, glucose, sucrose and dimethylsulfoxide). Synchronous cultures of larvae were removed from the batch culture at post-hatch intervals (0, 3, 6, 12 and 24 h) and instantaneously exposed to solutions at −1°C for 10, 30 or 90 min intervals. Survival of larvae placed in freezing solutions without cryoprotectant (control group) varied with larval age. In zero-hour post-hatch controls larval survival decreased linearily with increasing exposure time. Each older stage (control group), however, was insensitive to the duration of −1°C exposure. The addition of cryoprotectant to the chilled solutions radically modified survival patterns and yielded results dependent on age, cryoprotectant concentration, and exposure time. Survival in cryoprotectant solutions sometimes exceeded 200% of survival in control solutions. Three hour post-hatch specimens were generally most tolerant to chilling in cryoprotectant solutions, while 12 h nauplii were least tolerant. The significance of these results for the development of cryogenic larval banking techniques is discussed.