Feasible predictive criteria
for reproductive performance of white shrimp Litopenaeus vannamei:
egg quality and female physiological condition
F.G. Arcos, A.M. Ibarra, E. Palacios, C.
Vazquez-Boucard, I.S. Racotta-2003
Aquaculture, 228(1-4): 335-349
Abstract:
The present study analyzed the effects of consecutive
spawnings on egg quality in a homogeneous domesticated population of Litopenaeus
vannamei under optimal maturation conditions. A multidisciplinary
approach was used to evaluate egg quality and female condition, using
production, morphometric, biochemical, and histological criteria. For this
purpose, 106 individually tagged females were stocked with males in
maturation tanks, and productivity variables were recorded over 36 days.
Biochemical composition of eggs, hemolymph, hepatopancreas, and ovaries was
also analyzed. Results indicate that about half (48%) of females did not
spawn, 18% spawned once, 15% spawned twice, 11% spawned three times, and 8%
spawned four times or more. Variables associated with reproductive quality,
such as number of eggs per spawn, fertilization rate, and egg diameter, were
not affected by consecutive spawnings. Fourth-spawn eggs had significantly
higher levels of total lipids, triacylglycerides, and total proteins than
first-spawn eggs. First-spawn eggs from females that by the end of the
production period had spawned four or more times had higher
triacylglycerides and vitellin levels than first-spawn eggs from females
that had three or less spawns. This indicates that triacylglycerides and
vitellin could be used as predictors of female reproductive performance.
Significantly higher condition index (weight to length ratio) was observed
for females that spawned four or more times. No significant difference was
observed in biochemical composition of hepatopancreas and ovaries as a
function of the effect of number of spawns. This study indicates that egg
quality and physiological condition of females were not affected by
consecutive spawnings, and that females with multiple spawn capability are
desirable for greater reproductive performance. Production variables and
biochemical composition of first-spawn eggs and some morphometric
characteristics of females may be used as indicators of multiple spawn
capability.
(Programa
de Acuicultura, Div. Biologia Marina, Centro de Investigaciones Biológicas del Noroeste
(CIBNOR), Apdo. Postal 128, Mar Bermejo 195, C.P. 23090, La Paz, B.C.S.,
Mexico, e-mail of I.S. Racotta: iracotta@cibnor.mx)