Gonadal and extragonadal sperm reserves in the African sideneck Turtle (Pelusios castaneus)

Introduction: The African sideneck turtle (Pelusios castaneus), a freshwater turtle found in sub-Saharan Africa, recently became the focus of a number of biomedical research apart from its numerous trado-medical uses and very little consumption as meat in some quarters. This study was designed to investigate the gonadal and extragonadal sperm reserves of the African sideneck turtle, thereby generating data useful in the improved breeding of the animal. Methods: The gonadal and extragonadal sperm reserves of the African sideneck turtle were investigated using twenty adult male African sideneck turtles. Following anaesthesia and turtle dissection, the testis and epididymis were harvested and spermiogram investigated using standard techniques. Results: The mean testicular (gonadal) spermatozoa concentration of the P. castaneus was 48.50 ± 2.13 x 106/ ml, accounting for 27.5% of the total spermatozoa reserves, while that of the epididymis (extragonadal) was 127.61 ± 12.28 x 106/ml being 72.5% of the total sperm reserves with a significant difference (p < 0.05). The mean distribution of spermatozoa in the proximal, mid and posterior regions of the epididymis were 35.17 ± 8.23 x 106 /ml, 38.38 ± 5.85 x 106/ml and 54.06 ± 7.39 x 106/ml respectively, representing 27.56%, 30.01% and 42.36% respectively, of the total extragonadal sperm reserves of the P. castaneus. Significance: This report, being the first of its kind in this turtle, provides baseline data essential for a more productive selection of male turtles for breeding purposes as well as effective utilization of the sperm resources of the P. castaneus.