Effect of adding ozone into an intensive broiler production unit on performance, mortality, ammonia levels, and bacterial levels as compared with a non-ozone-treated broiler unit

Ozone is a very unstable and reactive molecule that can rapidly oxidize many organic substances and is often used for odor control. It is also known to be an effective biocide at high dose levels. Despite the lack of scientific evidence linking ozone to reduced aerial ammonia at levels that are safe for birds and humans, there is still an interest in the use of the product for commercial production poultry units. The objective of this experiment was to determine the effect of adding atmospheric ozone at a target level of 0.05 ppm (level achieved, 0.03 ± 0.017 ppm) to rooms housing broiler chickens. Female broiler chickens were grown in either an untreated environment or an environment with added ozone (3 rooms of 5 replicate pens, each containing 110 birds/treatment). Bird weight and feed consumption were recorded on a pen basis at 21 and 40 d of age; mortalities were collected daily, and necropsies were performed. Air samples were collected and plated on appropriate media to count total aerobic bacteria at 11, 19, and 34 d of age and enterobacteria at 34 d. Atmospheric ammonia levels were measured on d 15, 20, 28, 32, and 38. A significant (P < 0.05) improvement in feed conversion (feed:gain ratio) when corrected for mortality was noted in the ozone-treated birds (1.808 vs. 1.870). Birds exposed to ozone grew significantly slower (1.938 vs. 2.053 kg ofBW gain), consumed less feed (3.695 vs. 3.953 kg), and had a higher mortality (11.46 vs. 7.33%) and condemnation percentages (10.36 vs. 3.39%) than nontreated broilers. The addition of ozone caused no significant decrease in ammonia level or total bacterial count. The major increases in morbidity and mortality of the birds subjected to ozone make ozone gas unacceptable for use in a commercial broiler unit and raise serious health issues for both producers and birds.