Standardization of sperm cryopreservation techniques of Indian Major Carp Rohu (Labeo rohita, Hamilton 1822)

Abstract

This research dealt with standardization of sperm cryopreservation techniques of Labeo rohita. The concentration of sperm ranged from 8.55×109 to 8.57×109cells ml-1. Activation of sperm motility was decreased with increasing concentration of the extending media and motility was severely inhibited at 1% NaCl. The toxicity of cryoprotectant (DMSO and methanol) to sperm was tested at different concentrations (5%, 10%, 15%) and incubation time (5-35 min). Cryoprotectants with 5 and 10% concentrations produced better motility during 5 and 10 min incubation. Two extenders, Alsever’s solution and egg-yolk citrate, and two cryoprotectants, DMSO and methanol were used for cryopreservation of sperm. Alsever’s solution with 10% DMSO showed best performance producing 82.5±1.44% and 75.0±2.04% equilibration and post-thaw motility respectively. The fertilization and hatching rates were 62.0±0.80% and 45.5±1.78% for Alsever’s solution plus DMSO while those of 50.9±0.73% and 16±5.10% for egg-yolk citrate plus methanol respectively. Fresh sperm yielded 87.3±0.98% and 74.7±2.27% fertilization and hatching respectively. The breeding efficiency of cryopreserved sperm those were preserved with two diluents was compared and a significant variation was found for fertilization (P=0.001) as well as for hatching (P=0.006). The standardized cryopreservation techniques can be used to conserve the existing gene pool of rohu for cryogenic gene banking.