In Vitro Binding Capacity of Zeolite A to Calcium, Phosphorus and Magnesium in Rumen Fluid as Influenced by Changes in pH

Abstract

An in vitro experiment was designed to mimic the transport of ingested zeolite A in the forestomachs and proximal part of the small intestine so as to evaluate the binding capacity of zeolite A to Ca, P and Mg as influenced by changes in pH. This was done by incubation of rumen fluid solutions with and without zeolite, as well as varying the content of Ca and/or P. The pH was lowered by addition of HCl so as to mimic abomasal conditions, followed by subsequent HCO3- addition to mimic small intestinal pH. Rumen fluid samples were taken at strategic time points in the experiment. All samples were centrifuged and the supernatant analysed for Ca, P and Mg as indicators of the amount of unbound mineral. The addition of zeolite to rumen fluid solutions reduced the amount of supernatant Ca and Mg at rumen pH, whereas the level of P was not reduced. After adding HCl, a large proportion of the zeolite-bound Ca and Mg was released, increasing supernatant Ca and Mg levels; whereas, HCl addition led to a profound drop in supernatant P in zeolite samples, indicating binding of P. A low level of supernatant P was maintained after HCO3- addition. Neutralization by HCO3- led to a zeolite-induced drop in supernatant Ca and Mg. The reduction in supernatant Ca observed in the present study concurs well with the theoretical rationale of prepartum zeolite supplementation in milk fever prevention. Furthermore, the apparent binding of P by the zeolite may also contribute because of the connection between the calcium and phosphorus homeostasis. The zeolite-induced reduction in supernatant Mg indicates that zeolite supplementation should probably be avoided in Mg-deficient herds unless Mg supplementation is initiated.

Effects of Short-term Supplementation of Clinoptilolite in Colostrum and Milk on the Concentration of Some Serum Minerals in Neonatal Dairy Calves

“…On the other hand, in an in vitro study, researchers revealed significant effects of zeolite A addition to ruminal fluid at different levels of pH similar to various sections of alimentary tract. The authors believed that these changes could be resulted to hypomagnesaemia in vivo [21].…”

“…A low level of supernatant phosphorus was maintained after HCO −3 addition. Neutralization by HCO −3 led to a zeolite-induced drop in supernatant Ca and Mg [21]. In general, clinoptilolite is considered to be rather stable in the acid environment of the stomach without undergoing major degradation during its transit through the digestive tract [22].…”

Effect of zeolite A on rumen fermentation and phosphorus metabolism in dairy cows

“…Cows with a zeolite A supplementation in doses higher than 300 g/d showed a hypophosphataemia (Thilsing-Hansen et al 2002Enemark et al 2003;Grabherr et al 2008Grabherr et al , 2009Pallesen et al 2008). An addition of zeolite A to rumen fluid in vitro led to a decrease of supernatant phosphorus concentration after acidification with hydrochloric acid (Thilsing et al 2006). At acid pH, zeolite A may be destroyed releasing silicic acid, amorphous aluminium silicate and aluminium (Cook et al 1982).…”

Zeolite A effect on calcium homeostasis in growing goats1

“…In accordance with these findings, Enemark et al (2003) presented significantly lower Mg concentrations in serum of treated dry cows compared with control group. Furthermore Thilsing et al (2006) showed in an in vitro study, a zeolite-induced reduction of Mg in supernatants of rumen fluid. On the contrary, Pallesen et al (2008) observed no differences of serum Mg concentrations during zeolite application.…”

“…In an in-vitro study, Thilsing et al (2006) showed that zeolite might bind Ca in the rumen, but could release it again in the abomasum. Perhaps the capacity of zeolite to bind Ca in the rumen, especially in combination with the above mentioned release, might be too small to have a relevant effect on the Ca homeostasis of the goats.…”