Golz D I, Crenshaw T D
University of Wisconsin, Madison 53706.
J Anim Sci. 1991 Jun;69(6):2504-15. doi: 10.2527/1991.6962504x.
The apparent retention and excretion of cations and anions were evaluated in 20 growing pigs to study the mechanisms by which an interaction between dietary K and Cl levels affected growth. All pigs maintained a positive retention of K+ and Cl- regardless of the dietary levels. The K x Cl interaction observed in growth studies previously but not in this study could not be explained by a simple interaction of one ion on the retention of the other. When pooled across dietary Cl levels, an increase in dietary K levels from .10 to .60% resulted in a calculated increase in daily K+ intake of 4.86 meq/kg of BW. Sixty percent (2.99 meq) of the increased K+ intake was excreted in the urine and counterbalanced by a decrease in urine NH4+ (3.06 meq). This decrease in NH4+ excretion could account for essentially all of the increase in N retention (3.51 mmol) observed when dietary K levels were increased from .10 to .60%. Thirty-three percent of the increased K+ intake (1.62 meq) was retained, but the counter ion could not be determined. Retention of Cl- was not changed as dietary K levels were changed. When dietary Cl levels were increased from .03 to .57%, 69% (4.06 meq) of the calculated difference in Cl- intake (5.90 meq) was excreted in the urine, which must have been counterbalanced by a decrease in undetermined organic anions (1.77 meq) and HPO4 = (1.50 meq) excretion, with a tendency for an increased NH4+ (.82 meq) excretion. The counter ions required to balance the increased Cl- retention (1.82 meq) as dietary Cl levels were increased from .03 to .57% could not be identified. Shifts in the retention and urinary excretion of Ca++, Na+, HCO3-, and SO4= did not seem to be quantitatively important in identifying the mechanisms by which dietary K and Cl levels alter growth. Based on these results, we conclude that alterations in growth caused by changes in dietary K and possibly Cl levels are mediated via mechanisms involving renal NH4+ metabolism.
对20头生长猪的阳离子和阴离子的表观潴留及排泄情况进行了评估，以研究日粮中钾和氯水平的相互作用影响生长的机制。无论日粮水平如何，所有猪对钾离子和氯离子均保持正潴留。之前在生长研究中观察到但本研究未观察到的钾×氯相互作用，无法用一种离子对另一种离子潴留的简单相互作用来解释。当合并不同日粮氯水平的数据时，日粮钾水平从0.10%提高到0.60%，导致计算得出的每日钾离子摄入量每千克体重增加4.86毫当量。增加的钾离子摄入量的60%（2.99毫当量）经尿液排出，并通过尿液中铵根离子的减少（3.06毫当量）得到平衡。当日粮钾水平从0.10%提高到0.60%时，铵根离子排泄的减少基本上可以解释观察到的氮潴留增加（3.51毫摩尔）的全部原因。增加的钾离子摄入量的33%（1.62毫当量）被潴留，但平衡离子无法确定。随着日粮钾水平的变化，氯离子的潴留没有改变。当日粮氯水平从0.03%提高到0.57%时，计算得出的氯离子摄入量差异（5.90毫当量）的69%（4.06毫当量）经尿液排出，这一定是通过未确定的有机阴离子（1.77毫当量）和磷酸氢根离子（1.50毫当量）排泄的减少得到平衡，同时铵根离子排泄有增加的趋势（0.82毫当量）。当日粮氯水平从0.03%提高到0.57%时，平衡增加的氯离子潴留（1.82毫当量）所需的平衡离子无法确定。钙离子、钠离子、碳酸氢根离子和硫酸根离子的潴留及尿液排泄的变化，在确定日粮钾和氯水平改变生长的机制方面似乎在数量上并不重要。基于这些结果，我们得出结论，日粮钾以及可能的氯水平变化引起的生长改变是通过涉及肾脏铵根离子代谢的机制介导的。
