Effects of ethoxyquin feed preservative and peroxide level on broiler performance.

Rancidity development in feeds and feed ingredients reduces the feeds' nutritive value and produces toxic peroxides. This investigation was conducted to determine the effects of different levels of peroxide on broiler performance and to determine the effectiveness of ethoxyquin in ameliorating the adverse effects of peroxides. Poultry fat was oxidized to contain 0, 50, 100, and 175 meq peroxide/kg and added to diets to provide 0, 2, 4, or 7 meq peroxide/kg feed, respectively. Liquid ethoxyquin was incorporated into the diets at 0, 62.5, and 125 ppm. Each of the 12 diets was fed to 8 replicate pens with 35 males and 35 females/pen. Body weights at 21 and 42 days of age were significantly lower in birds fed diets containing 4 or 7 meq peroxide/kg feed. At 49 days of age, the reduction in body weight was significant only at the 7 meq/kg level. Reductions in feed efficiency showed a similar pattern, but the depression was significant only at the highest peroxide level. Supplementation of 62.5 and 125 ppm ethoxyquin resulted in significantly heavier birds at 49 days of age but had no significant effect on feed efficiency. Beneficial effects of ethoxyquin supplementation were evident at higher peroxide levels. The study showed that at least 4 meq peroxide/kg feed was required to significantly affect bird performance, and that the addition of ethoxyquin could alleviate the deleterious effects of dietary peroxide.