Effect of Different Feed Additives on Performance and Health Status of Broilers Challenged with Eimeria tenella

With antibiotic growth promoters (AGPs) being progressively banned, interest in natural alternatives like essential oils is exponentially increasing due to their many beneficial properties as feed additives. The aim of this study was to evaluate the effects of a combination of ginger, oregano, garlic and clove essential oils (EO-FIT® Poultry), and saponins as feed additives, defining their impact on performance and health status of broilers challenged with Eimeria tenella. One-year-old broiler chickens were assigned to 4 treatments with 3 replicates of 15 birds each during 42 days. These treatments were: T1 – Negative control [NC]: basal diet, T2 – Positive control [PC]: NC + challenge, T3 – PC + EO-FIT® Poultry; 1kg/ton, T4 – PC + saponins; 1 kg/ton. On 14d birds from treatments 2 to 4 were challenged with 8,500 oocysts of Eimeria tenella. Performance was measured at 21d, 28d and 42d of age. Intestinal lesion scoring (from 0 to 4) was carried out on 21d by necropsying 15 birds per treatment. At 28d, 15 additional animals per treatment were euthanized and oocysts per gram (opg) of caecal content quantified. Results were analyzed by one-way ANOVA using GLM procedure of SSPS v. 19.0. Weights obtained from 0-42d were not significantly different, although there was a trend (P=0.0817) suggesting an improvement in weight between animals from EO-FIT® Poultry treatment (3,037xg) and those treated with saponins (2,804yg), with no significant differences compared to NC (2,976xyg) or PC (2,982xyg). Globally (0-42d), performance figures were similar for all those challenged animals regardless of the treatment except for the FCR, which was significantly higher (P=0.0126) for birds treated with saponins (1.61c) compared to the NC and EO treatment (1.46a and 1.53ab respectively, 1.55bc for PC). The average gut lesion from the PC and saponin treatment (2.07 for both) was 23.95% higher than lesions from birds treated with EO-FIT® Poultry (1.67). No lesions were registered for NC treatment. Birds from the NC and EO-FIT® Poultry treatments had significantly lower oocyst presence in caecal content at 28d compared to the PC (1,286b, 10,753a, 546b and 2,808abopg for NC, PC, EO-FIT® Poultry and saponin, respectively; P=0.0084). That means that animals treated with EO-FIT® Poultry had a concentration of oocysts 94% lower compared to the PC. These results show that EO-FIT® Poultry was able to affect the parasite’s life cycle, although they could not significantly improve production performance or lesion scoring of challenged birds.