THE EFFECT OF EYESTALK ABLATION ON SPERMATOPHORE AND SPERM QUALITY INPenaeus vannamei

Publisher Website
Google Scholar
Abstract
The effects of eyestalk ablation on spermatophore and sperm quality inPenaeus vannameiwere investigated in bilaterally, unilaterally, and unablated males stocked at a 1:1 ratio with unilaterally ablated females. Males were evaluated for sperm quality by determining sperm count, percent live sperm and percent abnormal sperm from males at the initiation of the experiment (baseline), and at the end of the 104‐day experimental period. The bilateral treatment group was terminated at 56 days, due to excessive mortality. Data indicate that unilateral ablation enhances gonad weight, gonad index and spermatophore weight. Of critical importance is the fact that unilaterally ablated males demonstrated a significantly higher mean sperm count (81.8 million) than both the unablated controls (31.9 million) and the bilaterally ablated males (39.4 million). Additionally, neither unilateral nor bilateral ablation caused a decrease in sperm quality. Sperm viability profiles (i.e., percent live, and percent abnormal) determined for all treatments were not significantly different from one another. Values determined for mean percent live sperm were: 89.0, 98.6, and 99.0%, while average percentage abnormal sperm were: 10.5, 4.5, and 3.3% respectively for the control, unilateral, and bilateral treatments. These data suggest that unilateral eyestalk ablation enhances the reproductive capabilities of males by increasing sperm count, without diminishing sperm quality. The effects of these treatment manipulations on mating and hatch rate are briefly discussed.