Dietary folic acid requirement for maximum growth of juvenile tilapia Oreochromis niloticus x O. aureus
S.Y. Shiau, S.Y. Huang-2001
Fisheries Science, 67(4): 655-659
(from Current Contents)
Abstract :
A feeding trial was conducted to estimate the dietary
folic acid requirement of juvenile tilapia, Oreochromis niloticus x O.
aureus. Purified basal diets with eight levels (0.0, 0.3, 0.6, 1.0, 3.0,
6.0, 10.0, 20.0 mg/kg diet) of supplemental folic acid were fed to tilapia
(mean initial weight 0.41 +/- 0.01 g) for 8 weeks. Each diet was fed to
three replicate groups of fish reared in a closed recirculating system.
Results indicated that weight gain and feed efficiency (FE) were
significantly (P<0.05) greater in fish fed <greater than or equal
to>1.0 mg folic acid/kg diet than fish fed 0.3 mg folic acid/kg diet or
the unsupplemented control diet. Mortality of fish was not affected by
dietary treatment. Hepatic folic acid concentration increased with an
increase in dietary folic acid and values were significantly higher in fish
fed greater than or equal to 6.0 mg folic acid/kg diet than fish fed the
control diet. An analysis of the weight gain percentage by broken-line
regression indicates that the adequate dietary folic acid requirement in
juvenile tilapia is 0.82 mg/kg diet.
(Natl Taiwan Ocean Univ, Dept Food Sci, Chilung 202,
Taiwan, e-mail: syshiau@mail.ntou.edu.tw)