Effects of an aluminum-water treatment residual on performance and mineral status of feeder lambs

A 14-week experiment was conducted using 42 feeder lambs. Individual feeding was recorded between weeks 11 and 14. Diets, containing 0.25% P (as fed), included (1) control (10% sand), (2) (9.7% sand and 0.3% AlCl3), (3) (2.5% water treatment residual (WTR) and 7.5% sand), (4) (5% WTR and 5% sand), (5) (10% WTR and 0% sand), and (6) (10% WTR, 0% sand, double the added quantities of the mineral–vitamin premix, and 1.29% dicalcium phosphate). The total Al varied from 910 to 8000 ppm among diets. Lambs fed the control and WTR had no decline in intake, body weight (BW), or average daily gain (ADG) which may be attributed to the non-available Al found in WTR. Whereas lambs fed AlCl3 repeatedly had lower BW and intakes. During week 6, all treatments showed declines in plasma P, but the AlCl3 treatment often declined the most, and during week 11, plasma P began to increase. Accumulations of Al in the brain were greatest for lambs given 2000 ppm Al from AlCl3 and increased incrementally when Al as WTR was fed at levels higher than 2000 ppm. With the exception of the brain, soft tissues did not accumulate large amounts of Al during this 14-week experiment. Apparent P absorption from a 14-day metabolic study was positive (10.9–31.8%) for all lambs fed the control and various levels of WTR. However, lambs that received 2000 ppm Al via AlCl3 had a negative P absorption of −12.9%. This was lower (P < 0.05) P absorption compared to all other treatments. Aluminum, as AlCl3, fed at 2000 ppm reduced dietary P retention, but varying amounts of Al as WTR had no effect on P apparent absorption with similar absorption rates as the control. Therefore when dietary P is supplied in amounts of 0.25% or higher, Al (via WTR) fed to lambs in amounts as high as 8000 ppm did not negatively impact the feed intake, gain, BW, tissue P, plasma P, or P absorption. © 2006 Elsevier B.V. All rights reserved.