Effects of dilution ratio on the potency and viability of the spermatozoa of African catfish (Clarias gariepinus Burchell, 1822) using normal saline solution

Abstract

Normal saline solution is one of the most common diluents in artificial breeding and to dilute the milt of C. gariepinus, however the most desirable quantity or volume to be used is still a problem leading to several failures in artificial propagation of fish. The study determined the effects of dilution ratio on the potency of the spermatozoa, fertilization and hatchability rate of the eggs and survival rate of the hatchlings. The dilution ratio used included milt to saline solution ratio of: 1:10 (T2), 1:50 (T3), 1:100 (T4), and zero saline inclusion (T1), as the control. The experiment was laid out in a complete randomized design (CRD) with 3 replications each for the treatments. The result showed that there was significant difference (P<0.05) in percentage motility of the milt, egg fertilization and hatchability rate, and survival rate of the larvae across the treatments. The highest percentage motility (87.67%), fertilization (97.55%), hatchability (87.78%) and survival rate (I83.53%) occurred at T2 (1:10), while the least percentage motility (49%), fertilization (75.89%), hatchability (40.73%) and survival rate (45.43%) occurred at T1 (zero saline inclusion). It can be concluded that normal saline improves artificial propagation of C. gariepinus and with further increase of normal saline solution there is a negative effect on the potency of the milt, fertilization and hatchability of the eggs and survival rate of the hatchlings. A dilution ratio of 1:10 is therefore recommended to fertilize eggs of C. gariepinus for improving artificial propagation of fish.