Effects of Fluoride and Ethane-1-Hydroxy-1,1-Diphosphonate on Bone Metabolism in the Growing Chick

Abstract

White Leghorn cockerols were fed a semipurified diet (containing fluoride at 0 to 800 ppm) from the day of hatching. The birds were also injected daily with solutions containing ethane-1-hydroxy-1,1-diphosphonate (EHDP) at concentrations ranging from 5 to 20 mg as phosphorus/kg of body weight or isotonic saline. Changes in bone mineral composition and plasma Ca, Mg and F were determined as well as alterations in bone pyrophosphatase and the amounts of bone cyclic-3',5'-adenosine monophosphate (cAMP). Since dietary fluoride in high amounts is known to stimulate new bone formation, the purpose of the study was to assess whether a potent inhibitor of mineralization, such as EHDP, might alter the response to high dietary fluoride. Although bone fluoride and magnesium were increased in relationship to dietary fluoride, the administration of EHDP had little effect on these changes at low to moderate levels of fluoride. The levels of soluble bone pyrophosphatase were not greatly influenced by changes in dietary fluoride. Administration of EHDP at 20 mg P/kg, however, typically decreased the levels of bone pyrophosphatase. Bone cAMP did not appear to be influenced by either dietary fluoride or EHDP. Using tissue culture techniques, the effects of fluoride on calcium uptake and release from embryonic chick bone were also studied. The presence of 1 mM fluoride in the medium appeared to stimulate calcium uptake and reduced calcium release from chick bone. In general, the results were in keeping with previous suggestions that the major effect of fluoride on bone is the formation of fluoroapatite and subsequent effects this may have on other metabolic alterations.

Effects of ethane-1-hydroxy-1,1-diphosphonate (EHDP) upon the kinetics of bone resorption and bone formation at the whole bone level in prelabelled chicks

“…The small net increase in calcium mass observed weekly during four weeks was the result of a 90% inhibition of mineralization. These data are consistent with previous findings [10][11][12][13].…”

“…In vivo EHDP has been used to study calcium metabolism. Early studies demonstrated that EHDP administration (5-20 mg/kg) can inhibit bone mineralization in various species: cat [6], dog [7], rat [7][8][9], and chick [10][11][12][13]. The effect of EHDP has been ascribed to a direct inhibition of EHDP at the mineralization site [4] and inhibition of vitamin D activation of 25(OH)D3 to 1,25(OH)2D3 in chicks [11, 13,14] and rats [15,16].…”

Evaluation of an indigenous source of rock phosphate as a supplement for broiler chickens

“…The initial positive response in BW gain to HRP may be explained by some positive effect of the small amount of F in the diet (or perhaps some other contaminant in the HRP). One possible cause is from the well-known ability of fluoride to replace the OH − ion in hydroxyapatite in bone to form fluorapatite, a stronger, more stable constituent (Zipkin, 1970;Chan et al, 1976;Merkley and Miller, 1983;Huyghebaert et al, 1988).…”

“…Sullivan et al (1994) and Summers (1995) concluded that impurities like F could reduce the P utilization from rock phosphate compared with its pure form DCP. Fluorine is not considered to be an essential nutrient for poultry and is usually ignored by the poultry industry, yet indications exist that small quantities of dietary F can improve bone quality and improve overall performance of broilers (Zipkin, 1970;Chan et al, 1976;Merkley and Miller, 1983;Huyghebaert et al, 1988). In some countries, rock phosphate is processed for removing impurities, which further enhances its P utilization and reduces the risk of toxic minerals in finished feed.…”

Magnesium and Bone Disease

“…Cohen et al [40] have suggested that the magnesium malabsorption found in 12 of 20 of their osteoporotic patients may account for this magnesium deficiency state [40], Lowered bone magnesium content has been reported in diabetes [32,36] and in otosclerotic bone [41]. Increased magnesium levels have been reported in human fluorotic bone [42,43] and in quail [44] and chick [45,46] studies. However, when fluoride-supplemented animals are placed on a low-magnesium diet, bone magnesium de creased [47], Early work by Pellegrino and Biltz [48] showed no difference in magnesium content between control sub jects and patients with renal disease of less than 2 or more than 2 years.…”