**1. Introduction**

Coccidiosis is a worldwide disease caused by the Apicomplexa protozoa of Genus *Eimeria* [1]. This parasitic disease causes economic losses in poultry industry due to malabsorption, reduced weight gain (explained by a reduced feed intake and as well as nutrient absorption), increased mortality and the use of anticoccidial drugs and vaccines [2, 3] and remains as a major issue for poultry producers in a large number of countries including USA [4], costing for the global poultry industry over 3 billion dollars annually [5, 6]. However, subclinical coccidiosis (Coccidiasis) is

more costly to producers than clinical coccidiosis because of impairment on FCR (Feed Conversion Ratio) and decreasing in BWG (Body Weight Gain), slightly resistance of anticoccidials as well as the difficultness in the diagnostic [6, 7]. The infection with *Eimeria* begins when the bird ingests sporulated oocyst, and the sporozoite replication occurs in the intestinal cells generating damage in the mucosa [8]. The infection is normally caused because of mixture of *Eimeria* species. Each species develops in different regions of the intestine and they can cause mild to severe grades of lesions [9]. There are several *Eimeria* species that infect chickens, but the most important are *E. maxima, E. acervulina* and *E. tenella* [3]. The infection process is very fast, from 4 to 7 days, depending on the species [9]. Previous studies reported that a coccidia challenge resulted in 29.5, 24.7, 18.8, and 96.2% reductions in the apparent ileal digestibility of DM, N, starch, and fat, respectively. Interestingly, the negative effects of coccidia challenge on fat digestibility suggested complex mechanisms involved [10]. The strategies to reduce the impact of poultry coccidiosis including the use of anticoccidial drugs, vaccination programs and immunomodulators (e.g., nutritional strategies and functional ingredients including phytobiotics and probiotics).
