CRYOPRESERVATION OF CHANNEL CATFISH SPERM - STORAGE IN CRYOPROTECTANTS, FERTILIZATION TRIALS, AND GROWTH OF CHANNEL CATFISH PRODUCED WITH CRYOPRESERVED SPERM

We developed methods for cryopreserving sperm of channel catfish Ictal urus punctatus and evaluated the use of cryopreserved sperm for reprod uction. Five cryoprotectants were evaluated: methanol, glycerol, dimet hyl sulfoxide (DMSO), sucrose, and polyvinylpyrrolidone. We measured t he motility of sperm that had been stored at 4-degrees-C in three conc entrations of cryoprotectants (5%, 10%, 15%) dissolved in a modified H ank's balanced salt solution. All cryoprotectants reduced motility wit hin 6 h, 5% methanol and 5% DMSO caused the smallest reduction. After sperm were frozen at -80-degrees-C and stored for 2 d at -196-degrees- C, motility was highest (5-10%) in samples cryopreserved with 5% and 1 0% solutions of methanol. Sperm cells cryopreserved in methanol soluti ons (5%, 10%, and 15%) were used to fertilize channel catfish eggs fro m three females. Fertilization ranged from 24% to 97%, and no differen ce in fertilization success was found between cryopreserved sperm and untreated sperm from the same males. Growth of channel catfish produce d with cryopreserved sperm was not different from the growth of siblin gs produced with untreated sperm. Sperm cryopreservation offers utilit y as a routine method for gamete storage and genetic improvement of ca tfish.