Sperm quality of nile tilapia and hybrid tilapia induced by crude pituitary extract, human chorionic gonadotropin (HCG), and gonadotropin releasing hormone analogue (GnRHa) injection
Abstract:
This study was designed to evaluate sperm quality of sexually mature (Oreochromis niloticus) and hybrid tilapia (Oreochromis sp.) induced by crude pituitary extract, human chorionic gonadotropin and gonadotropin releasing analogue injection. Four-to-six-month-old male (tilapia, weighting 378.03+-21.17 g with average length of 22.17+-1.76 cm; hybrid tilapia, weighting 346.09+-3.66 g with average length of 21.18+-0.08 cm) were randomly assigned in four treatment groups, each 6 male tilapia per group receiving intramuscular injection. Sperm quality was determined prior to hormonal injection (day 0) and 1, 2 and 3 days post injection. Evaluation of sperm quality was accomplished by measuring expressible milt, sperm concentration, total number sperm, percentage motility, duration of sperm motility, spermatocrit, percentage of viability, and percentage of fertilization rate.Results showed increasing in sperm quality one day after injection among males. Across all treatments: sperm quality declined with time over the 3 day sampling period. Nice tilapia had superior sperm quality (expressible milt, sperm concentration, total of sperm number, sperm viability, and fertilization) than hybrid tilapia. Administration of Gonadotropin Releasing Hormone analogue resulted in no significant increase in sperm production and sperm quality, compared to crude pituitary extract and human Chorionic Gonadotropin administration.