Growth, feed efficiency and
feed intake of offspring from selected and wild Japanese flounder (Paralichthys
olivaceus)
H.Y.
Ogata, H. Oku, T. Murai-2002
Aquaculture, 211(1-4): 183-193
Abstract:
Feeding and starvation trials were conducted to
investigate the nutritional trait differences between the offspring from
broodstock under selective improvement for growth for two generations and
wild-caught broodstock of the Japanese flounder. In the feeding trial,
juveniles (initial mean body weight: 13.7 g for the selected line and 14.5 g
for the wild line, 25 fish/tank, triplicate groups) from both broodstock
were fed with either 61.4% crude protein-14.1% lipid diet (dry basis, diet
1) or 60.3% crude protein-16.4% lipid diet (dry basis, diet 2) for 6 weeks.
Two-way analysis of variance (ANOVA) revealed that the selected line had
significantly higher final body weight, weight gain and feed intake than the
wild line irrespective of the dietary treatment. When the size effect was
removed by analysis of covariance (ANCOVA), the selected line had superior
feed efficiency and higher feed intake than the wild line regardless of the
dietary treatment. Body lipid and energy contents were significantly higher
in the selected line than in the wild line though energy retention was not
significantly different between the lines. Feeding diet 2 (with a slightly
higher dietary lipid level) positively affected protein and energy retention
in the selected line without growth retardation. There was no effect of diet
on these traits in the wild line. In the 2-week starvation trial, there were
no noticeable differences in protein, lipid and energy expenditures between
the lines. The results of the present study demonstrate that the selected
line of the Japanese flounder had superior growth rate and greater feed
intake and that the improved growth rate was associated with better feed
efficiency. Moreover, the results suggest that many nutritional parameters
were influenced by genetic factors in Japanese flounder.