Quantifying the dietary potassium requirement of juvenile hybrid tilapia (Oreochromis niloticus x O. aureus).
An 8 week feeding trial was conducted to determine the dietary K requirement for juvenile hybrid tilapia (Oreochromis niloticus x O. aureus). Purified diets with eight levels (0, 1, 2, 3, 4, 5, 7, 10 g/kg diet) of supplemental K were fed to tilapia. Each diet was fed to three replicate groups of fish initially weighing a mean value of 0.77 (SE 0.01) g/fish in a closed, recirculating rearing system. Weight gain was higher (P < 0.05) in fish fed the diets supplemented with 2, 3 and 4 g K/kg diet than in fish fed diet with 10 g K/kg diet and the unsupplemented control diet. Gill Na+-K+ ATPase activity was highest in fish fed the diets supplemented with 1-3 g K/kg diet, followed by fish fed the diet with 5 g K/kg diet and lowest in fish fed the diet with 10 g K/kg diet. Whole-body K content in fish were generally increased as the dietary K supplementation level increased. Analysis by polynomial regression of weight gain and gill Na+-K+ ATPase activity and by linear regression of whole-body K retention of the fish indicated that the adequate dietary K concentration for tilapia is about 2-3 g/kg diet.
Shiau
S Y
SY
Department of Food Science, National Taiwan Ocean University, Keelung, Taiwan, ROC. syshiau@mail.ntou.edu.tw
Hsieh
J F
JF
D000704:Analysis of Variance; D000818:Animals; D004305:Dose-Response Relationship, Drug; D016014:Linear Models; D008297:Male; D017419:Potassium, Dietary / Q000008:administration & dosage* / Q000494:pharmacology; D012044:Regression Analysis; D000254:Sodium-Potassium-Exchanging ATPase / Q000502:physiology; D017210:Tilapia / Q000502:physiology*; D015430:Weight Gain
D017419:Potassium, Dietary; D000254:Sodium-Potassium-Exchanging ATPase