EFFECTS OF DIFFERENT NATURAL EXTENDERS ON SPERM COUNT, MOTILITY AND FERTILITY OF Clarias gariepinus (Burchell, 1822) FOR ENHANCEMENT OF FINGERLING PRODUCTION

*Onyia, L.U¹., Diyaware, M.Y²., Etah, S.O.¹& Ochokwu, I.J³.

¹Department of Fisheries, Modibbo Adama University of Technology, Yola.

² Department of Fisheries, University of Maiduguri; Maiduguri.

³Department of Fisheries and Aquacultural Technology, Federal University, Dutsinma.

Email: luconyiagmail.com.

ABSTRACT

The study assessed the effects of natural sperm extenders on the sperm count, motility and fertility of African mudfish (Clarias gariepinus) for artificial induced breeding and cryopreservation purposes. Three natural extenders were tested i.e. Coconut water, sugarcane water and soybean solutions were used. While the saline solution was used as a control. Semen samples (milt) were pooled from mature broodstock males weighing 600±100g and pre-extension qualities were evaluated for the fresh sperm.  Extenders of sugarcane, coconut, soybean and saline water which was used as control were prepared and diluted with sperm to give a sperm extension ratio of 1:20 (1ml of sperm: 20ml of the extender) and 5ml of the prepared solutions were measured in different storage bottles and placed on crushed ice at about 4⁰C which were used to fertilize ready isolated eggs at 0, 3 and 6 hour intervals of exposure at 4⁰C to assess the fertility. In general, the fertilization rates decreased with increasing duration. With respect to natural extenders, the saline solution showed the highest fertility of 71%, followed by soybean milk (69%) while coconut water recorded the least fertility. There significant difference(p<0.05) in the percentage fertility of milt among the sperm extenders. The motility of the extended sperms was viewed under microscope at x400 magnification and calculated. Soybean milk showed the highest motility rate of 65% and sperm count 0.690±0.050×10⁸ after 6 hours exposure as compared with other natural extenders. However, sperm count, motility and fertility decreased progressively as the period of storage increased.

Keywords: Coconut Water, Sugarcane Water, Soybean Milk, Spermatozoa, Fertilization, Motility, Clarias gariepinus