Effects of cryoprotectant toxicity on the embryos and larvae of pacific white shrimp Litopenaeus vannamei

We tested the toxicity of four cryoprotectants (methanol, ethylene glycol, propylene glycol and dimethyl sulfoxide (DMSO) on embryos and larvae of the Pacific white shrimp Litopenaeus vannamei. The developmental stages tested include prenauplius embryos. nauplius I (NI), nauplius III (N3), nauplius V (N5), protozoea I (ZI) and protozoea III (Z3). The animals were exposed to three concentrations of each cryoprotectant for 5, 10, 15, 20, 25, 30 and 60 min. We found that ethylene glycol was the least toxic cryoprotectant. Concentration of 30% v/v was well tolerated by ZI larvae for 20 min, yielding 83+/-7% revival. Methanol was less toxic than propylene glycol and DMSO, while the later two showed similar toxicity. Except for the Z3 stage, larvae of later developmental stages had higher tolerance to high concentrations and long exposure. time than did larvae of early stages. Prenauplius embryo is the most sensitive stage to the cryoprotectants tested. Toxicity of cryoprotectant was also concentration and exposure time dependent. Five min duration showed an overall viability of 86+/-4%, while 1-h exposure was fatal to embryos and larvae when concentration was above 10% v/v. Our study provides critical baseline data for attempts to cryopreserve embryos and larvae of the penaeid shrimps. (C) 2004 Elsevier B.V. All rights reserved.