SOME EFFECTS OF DIETARY ALUMINUM AND SILICON ON BROILER-CHICKENS

Experiments were conducted to determine whether dietary silicon will reduce the toxic effects of dietary aluminum on broiler chickens. The parameters measured were weight gain, feed efficiency, percentage bone ash, tibial dyschondroplasia, and the retention of calcium, phosphorus, and phytin phosphorus. Experiments 1 and 2 were conducted with casein and gelatin-based purified diets and Experiments 3 and 4 with corn and soybean meal-based practical diets. All experiments used day-old broiler cockerels and lasted 16 days. Aluminum significantly reduced weight gain, feed efficiency, and percentage bone ash in all four experiments. Aluminum supplementation reduced the incidence and severity of tibial dyschondroplasia, but this effect was associated with a reduction in weight gain. Increasing dietary aluminum reduced the retention of phosphorus and phytin phosphorus. Silicon did not alleviate the effects of aluminum toxicity on any of the parameters measured but did independently increase growth rate in Experiments 1 and 2. Supplementary dietary silicon does not appear to reduce aluminum toxicity in broiler chickens. Aluminum appears to exert its toxic effect on chickens by reducing the retention of phosphorus and phytin phosphorus.