Murai T, Andrews J W, Bauernfeind J C
J Nutr. 1978 Nov;108(11):1761-6. doi: 10.1093/jn/108.11.1761.
Purified diets with five levels (25, 50, 75, 100, and 200 mg/kg) of supplemental L-ascorbic acid (LAA), and equimolar levels of ethylcellulose coated L-ascorbic acid (EAA) and dipotassium L-ascorbate 2-sulfate dihydrate (AS) were pelleted and fed to 7.9 +/- 0.2 g channel catfish fingerlings for 20 weeks. A dietary level of 23 mg/kg of all three forms of vitamin C prevented spinal abnormalities. Approximately 50 mg/kg diet of either LAA or EAA was sufficient for maximal growth and feed efficiency. Growth response to AS was similar to a Michaelis-Menten type curve and 200 mg/kg diet of AS was necessary to achieve maximal growth. Blood and liver ascorbic acid levels were positively correlated with supplemental levels of LAA, EAA, and AS up to 200 mg/kg; however, blood and liver ascorbic acid levels of fish fed AS were considerably less than those fed LAA and EAA. Weight gains were positively correlated with blood ascorbate levels up to 7 microgram/ml. No measurable level of AS was detected in blood or liver. These results suggest that the rate of enzymatic hydrolysis of AS to LAA or rapid excretion of AS may have been the limiting factor.
将含有五种水平（25、50、75、100和200毫克/千克）补充L-抗坏血酸（LAA）以及等摩尔水平的乙基纤维素包衣L-抗坏血酸（EAA）和L-抗坏血酸2-硫酸二水合二钾（AS）的纯化日粮制成颗粒，投喂给平均体重7.9±0.2克的斑点叉尾鮰鱼苗20周。日粮中三种形式的维生素C含量为23毫克/千克时可预防脊柱异常。LAA或EAA日粮约50毫克/千克足以实现最大生长和饲料效率。对AS的生长反应类似于米氏类型曲线，日粮中200毫克/千克的AS是实现最大生长所必需的。血液和肝脏中的抗坏血酸水平与LAA、EAA和AS的补充水平呈正相关，最高可达200毫克/千克；然而，投喂AS的鱼的血液和肝脏抗坏血酸水平明显低于投喂LAA和EAA的鱼。体重增加与血液中抗坏血酸盐水平呈正相关，最高可达7微克/毫升。在血液或肝脏中未检测到可测量水平的AS。这些结果表明，AS酶解为LAA的速率或AS的快速排泄可能是限制因素。
