Effect of dietary calcium and phosphorus vitamin D metabolites 25(OH)D and 1,25(OH)2D, and response to bPTH (1-34) in blue duikers
Publication Type: |
Journal Article |
Year of Publication: |
2002 |
Authors: |
Beverly L. Roeder, Gabriella A. Varga, Robert F. Wideman, Bruce W. Hollis |
Publication/Journal: |
Zoo Biology |
Publisher: |
A Wiley Company, Inc., Wiley Subscription Services |
Keywords: |
blue duiker antelope, bpth, renal function, vitamin d |
ISBN: |
1098-2361 |
Abstract:
Abstract 10.1002/zoo.10016.abs In a colony of blue duiker antelope (Cephalophus monticola bicolor) at Pennsylvania State University, many animals had reversed Ca:P ratios and acid-base imbalance, and some developed urinary calculi. The purpose of this study was to investigate the relationship between age, dietary Ca, P, and the homeostatic mechanisms controlling their extracellular fluid levels. Sixteen males (1–5 years old) had serum and urine electrolytes and vitamin D metabolites evaluated before, during, and after bPTH (1-34) intravenous infusion while consuming 1.38%Ca:0.66%P, and after consuming one of four experimental diets (Ca and P: 0.5:0.4%, 0.8:0.8%, 0.8:0.4%, 1.25:0.4%) for four months. Pretrial, all duikers responded similarly to bPTH. Post-trial bPTH caused an increase in serum Ca and a decrease in P followed by a rebound in P in duikers consuming 0.4% P and either 0.5, 0.8, or 1.25% Ca, whereas the 0.8:0.8% (high P diet) caused a decline in serum Ca and no change in P, followed by an increase in serum P to higher levels than baseline. Vitamin D metabolites pretrial were similar between age groups and assigned treatment. Post-trial 1,25(OH)2D was significantly lower in younger males consuming diets with %Ca > %P than in older males. 25(OH)D was similar between age groups. Ca intake inversely affected 25(OH)D (P < 0.002) and was directly related to 1,25(OH)2D. P intake inversely affected 1,25(OH)2D (P < 0.04) and was directly related to 25(OH)D. This suggests that blue duikers have a unique ruminant response to PTH that is related to vitamin D metabolism as influenced by the dietary level of Ca and P, and the age of the animal. This may indicate an age-related impairment of 25(OH)D metabolism in young duikers, or a dependence on increased 1,25(OH)2D to maintain Ca and P homeostasis in older animals. Zoo Biol 21:171–183, 2002. © 2002 Wiley-Liss, Inc.