International Journal of Aquaculture, 2017, Vol.7, No.14, 94-100
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experience the natural conditions of the spawning grounds and as a result, the pituitary fails to release the
maturational gonadotropin, luteinizing hormone, LH; (Zohar and Mylonas, 2001). Storing batches of spermatozoa
by cryopreservation would significantly improve the reproductive potential of male catfish. African catfish is on
high demand in Nigeria. However, producing enough fingerlings poses a major problem. Also, increased
productivity is directly linked to increase in the number of offspring and their survival rate (Madu et al., 1998).
Obtaining genetically superior males as sperm suppliers would contribute immensely to this. The use of such
males could be optimized if there is enough facility to preserve their supplied sperm for longer periods, thereby
allowing females to be spawned when and where males are not available. Thus there is need for appropriate
cryoprotectants and freezing protocols.
Lack of a totally reliable method of long term preservation of milts creates the need for researches directed
towards developing adequate preservation protocols. The aim of the this study was therefore to test the adequacy
of a preservation protocol that involves the sperm sac intact with the objectives of evaluating the milt for
percentage live, motility and mass activity for a period of seven days at -20°C.
2 Results
2.1 Table 1
The physical parameters (weight, length and width) of the dissected left and right testes were recorded. Table 1
showed the results obtained. Also in Figure 1 we have a photograph of dissected testes of
Clarias gariepinus
showing both the left and right testes.
Table 1 Physical characteristics of both testes (sperm sacs)
Left testis
Parameter
Right Testis
5.1
Weight (g)
5.5
6.8
Length (cm)
7.8
1.4
Width (cm)
1.5
Figure 1 Photograph of dissected testes of
Clarias gariepinus
2.2 Table 2
Table 2 shows the pre-storage milt characteristics of both the left and right testes. Both had the same values except
in volume where the right testis was not extracted so the volume (ml) could not be determined.
