Effects of an Aluminum Supplement on Nutrients and Minerals Studied

Studies in ruminants and ponies found that high levels of aluminum disrupted the use of calcium and phosphorus. On the other hand, one study found no adverse effects on macro- or micromineral digestibility and balance when small amounts of aluminum (less than 1500 parts per million) were ingested.

How was the study conducted?

Four mature Thoroughbred geldings were used in the study. All horses ate a basal diet consisting of hay, sweet feed, and salt. The control diet provided 159.9 parts per million aluminum, or about 1 milligram of aluminum per kilogram of body weight per day. Horses on the aluminum-supplemented diet consumed an additional 227 grams of a supplement containing dihydroxy-aluminum sodium carbonate and aluminum phosphate, increasing aluminum in the ration to 930 parts per million and providing about 12 milligrams of aluminum per kilogram of body weight per day. Horses were given the dietary treatment for 28 days. For the last five days of each period, the horses wore a harness that allowed the complete and separate collection of urine and feces. Samples of feed, urine, feces, and blood were analyzed for various minerals, and calculations were made for digestibility of each nutrient. Results were compared between horses, periods, and treatments.

What results were found?

After one month on the aluminum-supplemented diet, there was minimal or no effect on mineral balance, nutrient digestibility, and blood biochemical variables. No difference was found between treatments on absorption, excretion, or retention of calcium, phosphorus, sodium, potassium, chloride, magnesium, zinc, copper, manganese, or boron. Horses consuming additional aluminum showed a slight decrease in the apparent digestibility of crude protein; a slight increase in urinary excretion of iron; and small decreases in sodium and bilirubin in the blood.