Effects of background color on growth performances and physiological responses of scaled carp (Cyprinus carpio L.) reared in a closed circulated system
Se. Papoutsoglou et al., Effects of background color on growth performances and physiological responses of scaled carp (Cyprinus carpio L.) reared in a closed circulated system, AQUACULT EN, 22(4), 2000, pp. 309-318
Growth performances and physiological responses of Cyprinus carpio after lo
ng-term (14 weeks) background color adaptation were investigated. Six group
s of ten individuals each (initial body weight 116 g) were reared in black,
green and white tanks (two replicate groups for each color). At the end of
the experiment, blood (cortisol, glucose, haematocrit, cholesterol, trigly
cerides, total lipids, osmolality, electrolytes, pCO(2), pH), liver (total
lipids, glycogen, hepatosomatic index) and growth (body weight, specific gr
owth rate, food conversion ratio, condition factor, proximate carcass compo
sition) parameters were determined. Plasma cortisol levels in white-adapted
carp were significantly (P < 0.05) lower than those in black, while in gre
en-adapted fish did not differ significantly from those in both other count
erparts. White-adapted carp showed the highest specific growth rate and the
lowest food conversion ratio, whereas black-adapted fish exhibited the opp
osite pattern. In addition, mean (%) increase of body weight in white-adapt
ed carp was 4.66 and 3.58% higher than that in black- and green-adapted fis
h, respectively. Furthermore in white-adapted carp, blood pCO(2) and pH wer
e significantly higher and lower, respectively, than those obtained in blac
k- and green-adapted fish. In black-adapted carp, liver total lipid levels
were significantly lower, and plasma total lipid levels were significantly
higher, than those in white- and green-adapted fish. No significant variati
ons were observed in the other parameters. It is concluded that different b
ackground colors may lead to different growth performances of scaled carp d
epending upon rearing conditions. (C) 2000 Elsevier Science B.V. All rights
reserved.