Lent A J, Wideman R F
Department of Poultry Science, Pennsylvania State University, University Park 16802.
Poult Sci. 1994 Jan;73(1):63-74. doi: 10.3382/ps.0730063.
Renal Ca and inorganic P (Pi) excretion were evaluated in Single Comb White Leghorn pullets reared on diets containing 1 or 3.5% Ca alone or supplemented with .6% DL-methionine or .53% ammonium sulfate. Plasma and urine samples were collected during a CONTROL period, and while 200 mM Ca was infused intravenously (Ca-LOADING). Excess Ca, whether supplied chronically in the feed or infused acutely into birds fed 1% Ca diets, significantly reduced glomerular filtration rates, effective renal plasma flow rates, and Pi excretion rates and significantly increased Ca excretion rates and urine pH. Birds fed diets supplemented with DL-methionine and ammonium sulfate maintained significantly lower plasma Ca concentrations during the CONTROL and Ca-LOADING periods than birds fed the respective 1 or 3.5% Ca basal diets. When compared with birds fed the respective 1 or 3.5% Ca basal diets, birds fed the 1% Ca diet supplemented with ammonium sulfate or the 3.5% Ca diet supplemented with DL-methionine had significantly higher absolute urinary Ca excretion rates during Ca-LOADING. Fractional Ca excretion during Ca-LOADING was significantly higher in birds fed 3.5% Ca supplemented with DL-methionine or ammonium sulfate than in birds fed the 3.5% Ca basal diet. These results indicate that DL-methionine and ammonium sulfate accelerated urinary Ca excretion and reduced Ca retention in the extracellular fluid. The hypercalciuric efficacies of DL-methionine and ammonium sulfate were revealed only when the filtered load of Ca was increased through intravenous Ca infusions.
在以仅含1%或3.5%钙，或添加0.6% DL-蛋氨酸或0.53%硫酸铵的日粮饲养的单冠白来航母鸡中，评估了肾钙和无机磷（Pi）排泄情况。在对照期以及静脉输注200 mM钙（钙负荷）期间采集血浆和尿液样本。过量的钙，无论是长期在饲料中提供，还是急性注入喂食1%钙日粮的鸡体内，均显著降低肾小球滤过率、有效肾血浆流速和Pi排泄率，并显著提高钙排泄率和尿液pH值。在对照期和钙负荷期，喂食添加DL-蛋氨酸和硫酸铵日粮的鸡，其血浆钙浓度显著低于喂食相应1%或3.5%钙基础日粮的鸡。与喂食相应1%或3.5%钙基础日粮的鸡相比，喂食添加硫酸铵的1%钙日粮或添加DL-蛋氨酸的3.5%钙日粮的鸡在钙负荷期间的绝对尿钙排泄率显著更高。在钙负荷期间，喂食添加DL-蛋氨酸或硫酸铵的3.5%钙日粮的鸡的钙排泄分数显著高于喂食3.5%钙基础日粮的鸡。这些结果表明，DL-蛋氨酸和硫酸铵加速了尿钙排泄，并减少了细胞外液中的钙潴留。仅当通过静脉输注钙增加钙的滤过量时，才显示出DL-蛋氨酸和硫酸铵的高钙尿效力。
