Cryopreservation of Carp Spermatozoa

A successful cryopreservation method would offer many advantages to an aquaculturist. Cryopreservation can provide a year round supply of seeds from desired species regardless of the spawning season and allow hybridization, greater ease in carrying out selective breeding and stock improvement. Studies were conducted on cryopreservation of spermatozoa from Indian major carps. Effect of different concentration of glycerol and equilibration periods on the post thaw motility of spermatozoa from Catla, Rohu and Mrigal were observed. The maximum motility (80 - 85%) was observed with the equilibration period of 20 - 40 minutes with the concentration of 10-15% of glycerol. Rohu showed the same trend with the maximum motility of 78-87%. In Mrigal maximum motility (85-88%) was observed with the equilibration time of (20-40 minutes) with the concentration of glycerol in between (10-15%). Like glycerol, the same type of experiment was conducted with Dimethyl sulphoxide (DMSO). Post thaw motility of cryopreserved spermatozoa in DMSO showed the same way as glycerol. Apart from the above, percentage of motility of spermatozoa was observed with respect to different thawing temperatures. Maximum motility was observed at the thawing temperature of 40oC in catla (85%), Rohu (80.00%) and Mrigal (83%). Interesting results were obtained from the fertilization studies of cryopreserved spermatozoa of Catla with the eggs from the matured Catla breeders. Fertilization rate of 75-80% and the hatching rate of 60% was observed from the above study. From the above results, it could be possible to use cryopreserved spermatozoa for commercial production of fish seeds in fish hatcheries.