Abstract: The objectives of this study were to determine the effects of different cryoprotectants on sperm viability and optimization of spermatophore cryopreservation protocol for durable storage of Banana shrimp (Penaeus merguiensis). Spermatophore suspended for 15 min in Calcium-Free saline (Ca-F saline), used CPA MgCl2 and with concentration (15%), thawing temperature was 27°C. Use 15 min equilibration in room temperature (25°C) overall. Exposure and cooling rate selected as 25, 20, 16, 4, 2, -4, -20, -80, -150°C/10 min. Examination of sperm viability used a modified eosin-nigrosin staining technique. The smallest reductions in apparent sperm viability occurred with MgCl2, however freezing protocol was developed using Ca-F saline containing 15% MgCl2. Spermatophores were cryopreserved using above exposure/cooling rate and -196°C in liquid nitrogen up to 180 days. Mean sperm viability for fresh (93.8±1.3%) and cryopreserved spermatophore held for 24 h and 60 days was 83.5±0.6 and 61±1.2 did not differ (p>0.05), however that for spermatophore stored in liquid nitrogen between 90 and 180 days were lower (p<0.05) and varied from 55.4±0.3-16.4±1.2. Spermatophores earlier held in liquid nitrogen for 60 and 90 days. However, storage beyond 90 days caused a significant decline (p<0.05) in sperm viability. Spermatophores kept for 120 and 150 days had viabilities of 48.9±0.9 and 32.4±0.9%, respectively. Cryopreserved spermatophore stored in liquid nitrogen from 150-180 days had low viabilities (<35%). Mean fertilization rate of P. merguiensis females artificially inseminated with cryopreserved spermatophore that had been stored in liquid nitrogen for 7-30 days and for 60-90 days were 73.9±1.5-66.7±3.1 and 67.3±3-64.1±2.1%, respectively whereas that of fresh spermatophore was 88.2±1.5%. Hatching rates of eggs fertilized with cryopreserved spermatophore kept for 7-30 days and for 60-90 days were 77.6±2.5-72.7±3.5 and 81.5±12.1-62.5±1.5 which were not different (p>0.05) from those of the control group 76.2±13.5%, respectively. In conclusion, Cryopreserved spermatophore held in liquid nitrogen l<90 days revealed high sperm viability although, for longer periods, sperm viability declined at 180 days.
A.J. Memon, A.D. Talpur, M.I. Khan, M.O. Fariddudin, J. Safiah, A.B. Abol-Munafi and M. Ikhwanuddin, 2012. Optimization of Spermatophores Cryopreservation Protocol of Banana Shrimp (Penaeus merguiensis) (De Man, 1888). Journal of Animal and Veterinary Advances, 11: 1688-1704.