|Nielsen, Forrest - Frosty|
Submitted to: Biological Trace Element Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2007
Publication Date: 2/10/2008
Citation: Turner, K.K., Nielsen, B.D., O'Connor-Robison, C.I., Rosenstein, D.S., Marks, B.P., Nielsen, F.H., Orth, M.W. 2008. Sodium zeolite A supplementation and its impact on the skeleton of dairy calves. Biological Trace Element Research. 121(2)149-159.
Interpretive Summary: Silicon has been long suspected to be a beneficial bioactive, if not essential, element for maintaining bone and joint health. In addition, supra nutritional intakes of silicon have been found to be beneficial to bone health in some experimental animal models. For example, supplements of sodium zeolite A, a compound containing aluminum and silicon, to commercial or natural diets decreased bone-related injuries in horses and enhanced bone strength in chicks. Thus, a study was performed with dairy bull calves to determine whether sodium zeolite A supplementation resulted in changes in markers of bone metabolism and in mineral composition of bone and cartilage that were associated with changes in bone mechanical strength. The silicon concentrations in bone and cartilage were not significantly changed by a dietary supplement (0.05% of body weight) of sodium zeolite A in milk replacer for 60 days. No differences were found in bone architecture or mechanical properties between calves fed no or supplemental sodium zeolite A. The high concentration of silicon normally in the milk replacer may have prevented a significant response to additional dietary silicon. Sodium zeolite A supplementation, however, increased aluminum concentrations in bone and cartilage and a marker of bone breakdown (deoxypyridinoline) in blood. Increased aluminum concentrations in bone have been found to be detrimental to bone health. Thus, feeding high amounts of sodium zeolite A as a source of silicon apparently does not result in beneficial effects on bone formation or health in calves already receiving relatively high amounts of silicon. Instead, the aluminum in sodium zeolite A may be of concern because of possible detrimental effects on bone turnover.
Technical Abstract: Twenty calves were placed on study at three days of age, and were placed according to birth order into one of two groups: SS, which received 0.05% BW sodium zeolite A (SZA) added to their milk replacer and CO, which received only milk replacer. Blood samples were taken on d 0, 30, and 60 for osteocalcin (OC) and deoxypyridinoline (DPD) analysis. On d 60, the calves were euthanized and synovial fluid, articular cartilage, and both fused metacarpals were collected for bone quality analyses such as architecture and mechanical properties, mineral composition, and glycosaminoglycan concentration. There were no differences in OC concentrations due to treatment (p=0.12), and CO calves had lower DPD concentrations than SS calves (p=0.01) but the OC to DPD ratio was not different between treatments (p=0.98). No differences in bone architecture or mechanical properties were detected. Sodium zeolite A supplementation increased cortical bone (p=0.0002) and articular cartilage (p=0.05) aluminum content. Glycosaminoglycan concentrations were not different in synovial fluid or cartilage. Supplementation of SZA appeared to alter the rate of bone turnover without altering bone strength. Aluminum concentrations in the bone and cartilage increased, which may be a concern though the long-term consequences of such remain to be determined.