Shiau Shi-Yen, Su Li-Wen
Department of Food Science, National Taiwan Ocean University, Keelung 202, Taiwan, ROC.
J Nutr. 2003 Feb;133(2):483-8. doi: 10.1093/jn/133.2.483.
Two growth experiments were conducted to estimate the minimum dietary iron requirement for juvenile hybrid tilapia, Oreochromis niloticus x O. aureus. Purified diets containing 0, 10, 30, 50, 100, 150, 200 and 400 mg Fe/kg from ferric citrate (Experiment 1) and 0, 10, 30, 50, 100, 150 and 200 mg Fe/kg from ferrous sulfate (Experiment 2) were fed to tilapia (mean initial weight: 0.63 +/- 0.01 g, Experiment 1; 0.64 +/- 0.01 g, Experiment 2) for 8 wk. In Experiment 2, 150 mg Fe/kg from ferric citrate was also included for comparison. The rearing water contained 1.07 micro mol/L iron, and supplemental levels were confirmed by analysis. Each diet was fed to three replicate groups of fish. In Experiment 1, weight gain and feed efficiency (FE) were highest (P < 0.05) in fish fed the diet supplemented with 150 mg Fe/kg, followed by fish fed diets with 50, 100 and 200 mg Fe/kg and lowest in fish fed the unsupplemented control diet. Hepatic iron concentration was highest in fish fed diets supplemented with >150 mg Fe/kg, followed by fish fed the diet with 100 mg Fe/kg and lowest in fish fed diets with </=10 mg Fe/kg. Hemoglobin (Hb) and hematocrit (Hct) were higher in fish fed diets with >/=100 mg Fe/kg and mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) were higher in fish fed diets with >/=150 mg Fe/kg than in fish fed the diet without iron supplementation. In Experiment 2, weight gain was higher in fish fed the diet with 50 mg Fe/kg than in fish fed diets with 150, 200 and </=30 mg Fe/kg. FE was higher in fish fed diets with 50 and 100 mg Fe/kg and the ferric citrate comparison diet than in fish fed diets with </=10 mg Fe/kg. Hepatic iron concentration was higher in fish fed diets with >/=50 mg Fe/kg and the ferric citrate comparison diet than fish fed diets with </=30 mg Fe/kg. Hb, Hct, MCV and MCH were higher in fish fed diets with >/=50 mg Fe/kg than in fish fed the unsupplemented control diet. Analyses by polynomial regression of weight gain and by broken-line regression of hepatic iron and blood Hb concentrations indicated that the dietary iron requirement for tilapia is approximately 150-160 mg Fe/kg and 85 mg Fe/kg with ferric citrate and ferrous sulfate as the iron source, respectively; it also appears that ferric citrate was approximately 50% as effective as ferrous sulfate in meeting the iron requirement.
进行了两项生长实验，以估计尼罗罗非鱼（Oreochromis niloticus）×奥利亚罗非鱼（O. aureus）幼鱼的最低日粮铁需求量。将分别含有0、10、30、50、100、150、200和400 mg铁/千克柠檬酸铁（实验1）以及0、10、30、50、100、150和200 mg铁/千克硫酸亚铁（实验2）的纯化日粮投喂给罗非鱼（平均初始体重：实验1为0.63±0.01克；实验2为0.64±0.01克），为期8周。在实验2中，还添加了150 mg铁/千克柠檬酸铁的日粮用于比较。养殖用水含铁量为1.07微摩尔/升，通过分析确认了添加水平。每种日粮投喂给三组重复的鱼。在实验1中，投喂添加150 mg铁/千克日粮的鱼体重增加和饲料效率（FE）最高（P<0.05），其次是投喂含50、100和200 mg铁/千克日粮的鱼，而投喂未添加铁的对照日粮的鱼最低。肝脏铁浓度在投喂添加>150 mg铁/千克日粮的鱼中最高，其次是投喂含100 mg铁/千克日粮的鱼，而在投喂含≤10 mg铁/千克日粮的鱼中最低。血红蛋白（Hb）和血细胞比容（Hct）在投喂含≥100 mg铁/千克日粮的鱼中较高，平均红细胞体积（MCV）和平均红细胞血红蛋白含量（MCH）在投喂含≥150 mg铁/千克日粮的鱼中高于未添加铁日粮的鱼。在实验2中，投喂含50 mg铁/千克日粮的鱼体重增加高于投喂含150、200和≤30 mg铁/千克日粮的鱼。FE在投喂含50和100 mg铁/千克日粮以及柠檬酸铁比较日粮的鱼中高于投喂含≤10 mg铁/千克日粮的鱼。肝脏铁浓度在投喂含≥50 mg铁/千克日粮以及柠檬酸铁比较日粮的鱼中高于投喂含≤30 mg铁/千克日粮的鱼。Hb、Hct、MCV和MCH在投喂含≥50 mg铁/千克日粮的鱼中高于未添加铁的对照日粮的鱼。通过对体重增加进行多项式回归以及对肝脏铁和血液Hb浓度进行折线回归分析表明，以柠檬酸铁和硫酸亚铁作为铁源时，罗非鱼的日粮铁需求量分别约为每千克日粮150 - 160毫克铁和85毫克铁；柠檬酸铁在满足铁需求方面的效果似乎约为硫酸亚铁的50%。
