Cryogenic and refrigerated
storage of Atlantic cod (Gadus morhua) and haddock (Melanogrammus
aeglefinus) spermatozoa
J.D. DeGraaf, D.L. Berlinsky-2004
Aquaculture, 234(1-4): 527-540
Abstract:
The aim of this study was to improve methods for
short- and long-term preservation of Alantic cod (Gadus morhua) and
haddock (Melanogrammus aeglefinus) spermatozoa. The effects of
extender composition, cryoprotectant concentration, freezing rate, and
dilution ratio on post-thaw sperm motility were examined. The fertilization
capacity of fresh and post-thaw sperm were compared and sperm viability, as
determined by differential fluorescent staining (propidium iodide/SYBR 14®),
was correlated with motility. The highest post-thaw motility was obtained
when sperm was diluted 1:3 with an extender containing glutathione, sucrose,
and potassium bicarbonate (modified Mounib's extender, MME), supplemented
with 10% DMSO and frozen at a rate of -5 °C min-1. The post-thaw
motility of cod (66±2.1%) and haddock (53±2.1%) sperm did not differ
between 5 and 90 days of storage but was lower than fresh sperm. No
difference in fertilization rate was found between fresh and post-thaw cod
sperm, but fertilization was lower using post-thaw haddock sperm when
compared to fresh ones. Spermatozoa motility was highly correlated (Adjusted
R2=0.94) with the proportion of cells that incorporated
SYBR 14®. Refrigerated cod and haddock sperm diluted 1:3 with MME remained
motile for 40 and 38 days, respectively. These results demonstrate that
spermatozoa of cod and haddock can be refrigerated or cryopreserved and
yield acceptable sperm motility and post-thaw fertilization rates.
(Department of Zoology, University of New Hampshire,
Durham, NH 03824, USA, e-mail of D.L. Berlinsky: david.berlinsky@unh.edu)