Essential Oils to Limit Coccidiosis Impact in Broilers

Antimicrobial alternatives are needed for organic production, but also for limiting drug resistance and complying with upcoming regulations and consumer demands. The aim of this study was to evaluate a mixture of essential oils (EOs) from star anise, thyme, garlic and cinnamon in broilers. Two trials were conducted in non-vaccinated and vaccinated broilers, using an Eimeria challenge of 200,000 sporulated oocysts of mixed Eimeria species harvested from field isolates. For the first trial, a total of 1,600 non-vaccinated Ross 308 males were allocated to four treatments: 1) noninfected, untreated (NU); 2) infected, untreated (IU); 3) infected, decoquinate-zoalene shuttle program (DZ); 4) infected EOs (EOs). For the second trial, 1,200 coccidiosis-vaccinated Ross 308 males were allocated to the three treatments: 1) NU; 2) IU; 3) EOs. Diets were offered to 8 replicates of 50 chickens for 34 days ad libitum. For trial 1, EOs did not affect average daily gain (ADG) or feed conversion ratio (FCR) in the starting (d0-d10) and growing periods (d10-d20), compared to IU birds. However, EOs increased ADG (+9.44 g/d, +9.0%, P<0.05) and improved FCR (−0.11, −7.2%, P<0.05) in the finishing period (d20-d34), compared to IU birds. At d34, EOs increased body weight (+129 g, +5.7%, P<0.05), compared IU birds. EOs showed the same performance as the conventional anticoccidial program (DZ). For trial 2, EOs increased ADG in the starting (+0.73 g/d, +3.6%, P<0.05) and growing periods (+6.69 g/d, +13.6%, P<0.05), but not in the finishing period, compared to IU birds. EOs also improved FCR in the starting (−0.07, −5.8%, P<0.05) and growing periods (−0.19, −12.3%, P<0.05), but not in the finishing period, compared to IU birds. Overall (d0-d34), EOs improved FCR (−0.03, −2.4%, P<0.05), compared to IU birds. For the two trials, EOs did not affect oocyst excretion and lesion scores 5- and 6-day post-infection, respectively, compared to IU birds. Overall, the EOs showed performance at the same level of the anticoccidials and improved vaccination in Eimeria-challenged broilers. This mixture of EOs could be involved in a strategy to limit coccidiosis impact in broiler production.

Key words: feed additives, coccidiosis, organic, broilers.

Presented at the 2021 Animal Nutrition Conference of Canada. For information on the next edition, click here.