Vitamin C Research Today is a free monthly online journal that collates and summarizes the latest research about Vitamin C, including details on benefits, dosage, supplements, information. | ||||||||
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The effect of vitamin C supplementation on plasma concentration and urinary excretion of vitamin C in cattle.Padilla L, Matsui T, Ikeda S, Kitagawa M, Yano H Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan. We investigated the plasma concentration and urinary excretion of vitamin C in cows supplemented with vitamin C. Five cows (mean BW = 597 kg) were allocated to a 5 x 5 Latin square design and supplemented with a vitamin C preparation coated with hydrogenated soybean oil at 0, 10, 20, 40, or 60 mg of vitamin C per kg of BW per day for 9 d. Plasma and urine samples were collected for measuring vitamin C concentration. Urinary excretion of vitamin C was expressed as the ratio of vitamin C to creatinine. Plasma vitamin C concentration and urinary vitamin C excretion increased quadratically as dietary vitamin C increased (P < 0.001); that is, the lowest dose affected neither plasma vitamin C concentration nor urinary vitamin C excretion but the plasma vitamin C concentration and urinary vitamin C excretion increased (P < 0.05) with increasing supplementation of vitamin C at greater doses. This suggests that plasma vitamin C concentration affects urinary excretion of vitamin C in cattle and that plasma vitamin C concentration exceeded the renal threshold for vitamin C in the cows receiving vitamin C at 20 mg/kg of BW per day. Furthermore, increased urinary excretion of vitamin C appears to limit plasma vitamin C concentration in response to vitamin C intake. The daily excretion of vitamin C was estimated by the reported value of daily creatinine excretion, indicating that the daily amount of vitamin C excreted into urine was more than half of supplied vitamin C. Therefore, a large part of supplied vitamin C probably escapes ruminal degradation and is absorbed but excreted into urine. Published 20 November 2007 in J Anim Sci, 85(12): 3367-70.
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