EFFECTS OF EXTENDER TYPE, DILUTION LEVEL, AND STORAGE DURATION ON SPERM QUALITY AND REPRODUCTIVE PERFORMANCE OF PRESERVED Clarias gariepinus MILT

Abstract

Success in the production of Clarias gariepinus through artificial propagation via hatchery culture is influenced
by the quality of sperm used for fertilization. This study investigated the impacts of extender type, diluent level,
and preservation periods on sperm quality and the reproductive efficiency of the preserved milt. Fresh milt was
diluted with goat milk, chicken egg yolk, and glycerol at 10%, 20%, and 30% concentrations using trisodium
citrate buffer and preserved for up to 144 hours at 4°C. Sperm quality parameters (motility, viability,
concentration, morphology, and lipid peroxidation) were measured at 24-hour intervals while reproductive
performance indices (fertilization, hatchability, and larvae survival rate) were determined at 0, 72, and 144
hours.The motility of sperm gradually reduced as the storage period increased. Sperm quality declined
progressively with increasing storage duration across all treatments, with differences becoming more pronounced
at higher dilutions and longer storage periods. Goat milk consistently maintained superior sperm quality, with
higher motility, viability, and normal morphology, alongside moderate lipid peroxidation levels. Chicken egg yolk
provided moderate short-term preservation but deteriorated with extended storage, while glycerol showed the
poorest performance. Reproductive performance followed similar trends, with goat milk maintaining higher
fertilization (75-80%), hatchability (>80%), and larval survival up to 72 hours compared to other extenders.
Fresh milt showed optimal performance at 0 hours but declined rapidly without preservation. At 144 hours,
reproductive performance was significantly reduced across all treatments, indicating the biological limits of
chilled storage. The study concludes that goat milk is an effective, low-cost natural extender for short-term
preservation of C. gariepinus milt, with optimal results at 30% dilution within 72 hours at 4°C.