The influence of temperature
and ration on growth, feed conversion, body composition and nutrient
retention of juvenile turbot (Scophthalmus maximus)
E.H. Van Ham, M.H.G. Berntssen, A.K. Imsland, A.C.
Parpoura, S.E. Wendelaar Bonga, S.O. Stefansson-2002
Aquaculture, 217(1-4): 547-558
Abstract:
The influence of two water temperatures (16 and 22 °C)
on growth, feed conversion, body composition and nutrient retention was
investigated in juvenile turbot fed to satiation (0.9% and 1.1% bw day-1
at 16 and 22 °C, respectively) and at restricted rations of 65% and 35% of
the satiation level at each temperature. Fish fed the same % rations at 16
and 22 °C did not differ in final mean weight or specific growth rate,
which decreased at restricted rations. Feed restriction did not result in an
increase in size heterogeneity over time at any temperature, as indicated by
the stability of the coefficients of variation of weight (DCVw=1.00–1.13%).
At both temperatures, the best feed conversion efficiency (FCE) was found at
the 65% ration, and the FCE from fish fed the same rations was higher at 16
°C (1.30 g g-1) than at 22 °C (1.17 g g-1). A
similar trend was found in energy and protein retention levels. At both
temperatures, fish fed 35% rations had lower body lipid and higher ash and
moisture content compared to fish fed to satiation, with the most pronounced
effects on lipid (4.8% vs. 7.8% bw) and ash (4.1% vs. 3.6% bw) at 22 °C.
Feeding ration proved to be the main differentiating factor in all growth,
feed conversion and body composition parameters, whereas additional
temperature and/or interaction effects were found in FCE, whole body
protein, lipid, moisture and energy contents. Between fish fed 100% and 65%
rations, only minor differences were found, but at 35% ration, the rearing
temperature of 22 °C had a pronounced negative influence, and resulted in a
reduction of available anabolic energy for growth and adaptive responses.
(Department of Animal Physiology, Faculty of Science,
University of Nijmegen, Toernooiveld 1, 6525 ED, Nijmegen, The Netherlands,
e-mail of A.C. Parpoura: alparp@teimes.gr)