Shiau Shi-Yen, Lu Li-Shan
Department of Food Science, National Taiwan Ocean University, Keelung 202, Taiwan.
Br J Nutr. 2004 Apr;91(4):585-90. doi: 10.1079/BJN20041091.
Two 8-week feeding trials were conducted to determine the dietary Na requirement for juvenile hybrid tilapia (Oreochromis niloticus x O. aureus) reared in fresh water and seawater. In each experiment, NaCl was added to the basal diet at 0, 0.5, 1, 2, 3, 5, or 7 g Na/kg diet (fresh water) and at 0, 0.2, 0.5, 0.8, 1.2, 1.5, 2, or 3 g Na/kg diet (seawater). Each diet was fed to three replicate groups of fish, individual fish initially weighing 0.69 (se 0.01) g, in a closed, recirculating rearing system. In fresh water, the tilapia fed the diet supplemented with 2 g Na/kg diet had significantly (P<0.05) greater weight gain than the fish fed the diets supplemented with >/=3 and </=0.5 g Na/kg diet. Feed efficiency (FE) in fish generally followed the weight-gain pattern. Gill Na(+)-K(+) ATPase activity was highest in the fish fed the diets supplemented with 1-3 g Na/kg diet, followed by the fish fed the diet with 7 g Na/kg diet and lowest in the fish fed the unsupplemented control diet. In seawater, the weight gain, FE and gill Na(+)-K(+) ATPase activity in fish were not affected by the dietary treatment. Analysis by polynomial regression of weight gain, by broken-line regression of gill Na(+)-K(+) ATPase activity and by linear regression of whole-body Na retention of the fish reared in fresh water, indicated that the adequate dietary Na concentration for tilapia is about 1.5 g/kg diet. The present study also suggests that no dietary Na is required for tilapia reared in seawater.
进行了两项为期8周的饲养试验，以确定淡水和海水中养殖的杂交罗非鱼幼鱼（尼罗罗非鱼×奥利亚罗非鱼）的日粮钠需求量。在每个实验中，在基础日粮中添加氯化钠，添加量分别为0、0.5、1、2、3、5或7克钠/千克日粮（淡水）以及0、0.2、0.5、0.8、1.2、1.5、2或3克钠/千克日粮（海水）。每种日粮投喂三组重复的鱼群，初始体重为0.69（标准误0.01）克的单尾鱼，养殖于封闭循环养殖系统中。在淡水中，投喂添加2克钠/千克日粮的罗非鱼的体重增加显著（P<0.05）高于投喂添加≥3克钠/千克日粮和≤0.5克钠/千克日粮的鱼。鱼的饲料效率（FE）通常遵循体重增加模式。鳃钠钾ATP酶活性在投喂添加1 - 3克钠/千克日粮的鱼中最高，其次是投喂7克钠/千克日粮的鱼，在未添加钠的对照日粮组鱼中最低。在海水中，日粮处理对鱼的体重增加、饲料效率和鳃钠钾ATP酶活性没有影响。对淡水中养殖的鱼的体重增加进行多项式回归分析、鳃钠钾ATP酶活性进行折线回归分析以及全身钠保留进行线性回归分析表明，罗非鱼的适宜日粮钠浓度约为1.5克/千克日粮。本研究还表明，海水中养殖的罗非鱼不需要日粮中添加钠。
