Sperm quality over
consecutive spermatophore regenerations in the Pacific white shrimp
Litopenaeus vannamei
B.P. Ceballos-Vazquez, B. Aparicio-Simon, E.
Palacios, I.S. Racotta-2004
Journal of the World Aquaculture Society, 35(2):
178-188 (from ISI Current
Contents)
Abstract::
The reproductive potential of males plays an important role in the
productivity of captive penaeids. Males present a large variability in their
reproductive potential, and thus the selection of appropriate males for
reproduction is highly desirable. The present study compares sperm quality
at the beginning of the experiment (baseline values) with variations in
sperm quality as a result of consecutive spermatophore regenerations. This
was done to evaluate possible predictive criteria for optimal sperm quality
based on morphological and biochemical criteria in pond-reared Pacific white
shrimp Litopenaeus vannamei males. Sperm quality was similar between left
and right spermatophore. Sperm count and proportion of normal sperm
increased by 86 and 65% (P < 0.05) respectively, from baseline values to
third spermatophore regeneration. Proportion of dead sperm progressively
decreased with consecutive regenerations, attaining values 33% lower by the
third regeneration, compared to baseline values. This indicates that no
decrease in sperm quality occurs in L. vannamei during consecutive
regenerations and that the existing spermatophores at stocking of males
should be expelled to have higher sperm quality in regenerated
spermatophores. Furthermore, this procedure allows selecting individuals
with high baseline sperm quality based on significant correlations between
baseline and regenerated sperm quality observed in the present work.
Baseline values of glucose concentration in the hemolymph were positively
correlated to baseline values of sperm count (r = 0.3, P < 0.05). In
contrast, baseline values of several lipids in the hemolymph were negatively
correlated to several traits of sperm quality at first sampling (baseline
values) or at first regeneration. These results are discussed in terms of
nutritional requirements of males and of possible predictive criteria of
sperm quality.
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