Ovarian
maturation of wild Farfantepenaeus paulensis in relation to
histological and visual changes
S. Peixoto, R.O. Cavalli, F. D'Incao, Â.M. Milach, W. Wasielesky-2003
Aquaculture
Research, 34(14): 1255-1260
Abstract:
The present study describes the ovarian
development stages of wild Farfantepenaeus paulensis (Pérez-Farfante)
through the combined observation of histological and visual characteristics.
Twenty-five females (61.8±2.4 g) were captured in 35-40-m deep waters
off southern Brazil (27°S). The females were grouped according to the size
and shape of their ovary and then killed. The colour of the fresh ovary was
compared with a chromatic scale catalogue. Analysis of the histological
sections of each ovary determined the morphological characteristics, size
and frequency of the different oocyte types. Based on these characteristics,
four distinct stages of ovarian maturation are proposed: stage I (immature),
characterized by the presence of small basophilic oocytes (52.1±19.9 µm)
and ovary colour ranging from translucent to creamy; stage II (developing),
with yolky oocytes (YOs) (144.2±26.1 µm) and a light green colour;
stage III (mature), presenting large YOs but with cortical rods (235.0±30.2 µm)
and an olive-brown colour; and stage IV (spent), with atretic oocytes and
the same ovary colour pattern as stage I. The gonadosomatic index ranged
from 1.6 (stage IV) to 13.7% (stage III) and was closely related to the
different ovarian maturation stages. The observation of visual features
coupled with histological characteristics was found to represent a reliable
procedure to evaluate the ovarian maturation of F. paulensis.
(Laboratório de Maricultura, Departamento
de Oceanografia, Fundação Universidade Federal do Rio Grande, C.P. 474,
96201-900, Rio Grande, RS, Brazil)