Sperm quality in relation to
age and weight of white shrimp Litopenaeus vannamei
B.P. Ceballos-Vázquez, C. Rosas, I.S. Racotta-2003
Aquaculture, 228(1-4): 141-151
Abstract:
Optimal sperm quality is an important feature for
management of shrimp broodstock. The understanding of the sperm quality in
relation to age and weight of shrimp is useful to select male broodstock. To
evaluate the effect of age and weight on sperm quality, Litopenaeus
vannamei males from the same cohort at ages of 6, 8, 10, and 12 months
were examined, using body weight as a covariable in ANCOVA. Additionally,
males of the same cohort at an age of 12 months, but from different culture
conditions, were compared. Spermatophore weight, sperm count, and percentage
of normal sperm were positively correlated to body weight. Sperm count was
positively correlated to spermatophore weight and percentage of normal
sperm. Males at an age of 12 months had superior sperm quality than younger
males, based on observations of larger spermatophore weight, higher sperm
count, and higher percentage of normal sperm. By eliminating the influence
of body weight with the use of ANCOVA, the same effect was still observed,
indicating that the effect of age of males on sperm quality was independent
of body weight. However, when large differences in growth were forced by
changing culture conditions, sperm quality differences were observed and
could be explained by body weight. In conclusion, using 12-month-old males
would lead to improved shrimp seed production, since they are mature males
with high sperm quality. In addition, for improved productivity, it is
important to consider the culture conditions under which domesticated male
broodstock will be obtained.
(Centro de Investigaciones Biológicas del Noroeste,
Division de Biologia Marina, Apartado Postal 128, 23000, La Paz, Baja
California Sur, Mexico, e-mail of I.S. Racotta: iracotta@cibnor.mx)