Serum calcium, phosphorus and magnesium responses to massive dosing of cholecalciferol (CC) and 25-OH-CC in young and aged ewes
Thomas, B.B.; Boling, J.A.; Muir, W.M.
International Journal for Vitamin and Nutrition Research. Internationale Zeitschrift für Vitamin- und Ernahrungsforschung. Journal International de Vitaminologie et de Nutrition 51(4): 365-372
1981
ISSN/ISBN: 0300-9831 PMID: 6276316 Document Number: 177999
Ewes (24) were divided into 2 age groups, 1 year old and 9 years old, and used to study the influence of cholecalciferol (CC) and 25-hydroxycholecalciferol (25-OH-CC) on serum concentrations of calcium, phosphorus and magnesium with time after injection. They were maintained in slatted-floor pens and given 800 g diet daily which had Ca 0.38, P 0.31 and Mg 0.14% throughout the 21-day trial. The ewes were injected initially and on day 7 with (control) 5 ml ethanol, 50 mg CC in 5 ml ethanol or 25 mg 25-OH-CC in ethanol. Blood was sampled before injection (day 0) and on days, 1, 2, 3, 5, 7, 9, 12, 17 and 21 of the trial. Serum Ca was 10.81, 11.06 and 11.25 mg/100 ml for the ewes 1 year old and 10.51, 11.06 and 11.54 mg/100 ml for those 9 years old across sampling times in the respective groups. Serum P across sampling times averaged 6.58, 7.80 and 9.51 mg/100 ml in ewes 1 year old and values were different (P<0.05) from each other. Serum P was 7.06, 8.56 and 8.59 mg/100 ml for the ewes 9 years old. Serum Mg was 2.51, 2.32 and 2.19 mg/100 ml for the ewes 1 year old and 2.38, 2.14 and 2.00 mg/100 ml for those 9 years old. Serum Mg in ewes 1 year old was lower (P<0.05) in those given CC and 25-OH-CC than in controls, and was lowest (P<0.05) for those given 25-OH-CC when compared with control ewes 9 years old. External signs of hypervitaminosis were apparent after the second injection with 25-OH-CC, and were most pronounced in the older ewes.