Effect of cryoprotectants and cooling rates on fertility potential of sperm in the giant freshwater prawn, Macrobrachium rosenbergii (De Man).
This study evaluates freezing protocol with suitable cryoprotectants and their effects on the fertility potential of sperm in the cryopreserved spermatophores of Macrobrachium rosenbergii. Spermatophores, collected using electroejaculation, were suspended in dimethyl sulfoxide (DMSO), propylene glycol (PG), methanol, glycerol and ethylene glycol (EG) at different concentrations (10, 15 & 20% v/v), prepared in sterile-filtered pond water. Based on the cryoprotectant toxicity assay, DMSO and PG were used individually as well as in combination with three freezing protocols (i.e. -1.5, -3 and -5°C/min and to final temperature of -39°C) and plunged into liquid nitrogen at -196°C. After 90 days of storage (-196°C) thawing was done at 35°C in a water bath for 1min. Results showed that fresh and cryopreserved spermatophores held for 90 days registered sperm viability of 91.4±2.9% and 50.4±1.9% respectively. Further, fertility potential of sperm was assessed based on acrosome reactivity using calcium ionophore (A23187). Observations indicated that cryopreserved sperm registered 28.3±2.2% of acrosome reactivity compared to freshly collected spermatophores (85.3±2.5%). Thus, one-step slow cooling rate of -1.5°C/min between 27°C and -39°C stored in liquid nitrogen at -196°C with DMSO (10%)+PG (10%) seems to be amenable for cryopreservation of spermatophores, compared to other cooling rates.
Unit of Aquaculture & Cryobiology, Department of Zoology, University of Madras, Guindy Campus, Chennai, Tamil Nadu, India. Electronic address: v.teenaval@gmail.com.
P
P
Valentina Claudet
Unit of Aquaculture & Cryobiology, Department of Zoology, University of Madras, Guindy Campus, Chennai, Tamil Nadu, India. Electronic address: selva1704@gmail.com.
Selvakumar
S
Narasimman
Unit of Aquaculture & Cryobiology, Department of Zoology, University of Madras, Guindy Campus, Chennai, Tamil Nadu, India. Electronic address: munuswamynm@yahoo.com.
Munuswamy
M
Natesan
D020101:Acrosome Reaction / Q000187:drug effects; D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D015925:Cryopreservation; D003451:Cryoprotective Agents / Q000494:pharmacology*; D008297:Male; D033541:Palaemonidae / Q000502:physiology*; D012662:Semen Preservation; D013094:Spermatozoa / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure
D003451:Cryoprotective Agents
Acrosome reaction; Dimethyl sulfoxide+propylene glycol; Macrobrachium rosenbergii; Spermatophores