EFFECTS OF DIET SUPPLEMENTATION WITH CARP OVARY ON GONAD DIFFERENTIATION AND GROWTH OF THE EUROPEAN EEL
G. Grandi, F. Poerio, G. Colombo, M. Chicca-2000
Journal of Fish Biology, 57(6): 1505-1525
Abstract:
Treating elvers of European eel Anguilla
anguilla with mature carp ovary for 3-6 months during early growth
induced female differentiation in 51.6-66.7% of treated
animals compared with c.5% in controls. The treatment
also induced differentiation of ovaries in eels
<13cm LT and a higher number of Syrski organs
with ambisexual characters, and was most effective when
administered at an early growth stage. The results could
be attributed to the natural steroid content of the
carp ovary. The total weight of treated animals
at the end of the farm experiment was 84.7% higher than
controls. The specific growth rate for weight was
significantly higher in female yellow eels than in males,
for both control and treated groups. The enhanced
growth was related to induced feminization. A diet supplementation
with mature carp ovary could be a good approach to
control of sex differentiation and growth in eels.
(Department of Biology (Evolutionary Biology Section), University of
Ferrara, via L. Borsari 46, 44100, Ferrara, Italy)