## 1 Introduction  
Clostridia are anaerobic, Gram-positive, and spore-forming rod-shaped bacteria that are found in the gastrointestinal tract of wild and domestic birds [1]. _Clostridium perfringens_ (_C. perfringens_) is associated with four economically significant diseases: botulism, ulcerative enteritis, necrotic enteritis (NE), and gangrenous dermatitis. To cause lesions or a diseased state in the host, _C. perfringens_ releases toxins [2]. In chickens, the _NetB_ gene, encoding necrotic enteritis B-like (NetB) toxin, has been recently shown to play a leading role in the virulence of NE in the United States [3; 4], and studies have demonstrated that tpeL and alpha toxin (\(\alpha\)-toxin) also play a role in NE virulence [5; 6]. Therefore, a strain of _C. perfringens_ that is _NetB_-positive has been used to induce NE [7]. Similarly, _Eimeria tenella_ (_E. tenella_) is a protozoan that causes coccidiosis in many animals, including poultry. Coccidiosis leads to hemorrhagic lesions of varying severity depending on the age of bird and strain and the dose of infecting pathogen [8]. Moreover, the coinfection of _Eimeria tenella_ and bacterial pathogens such as _C. perfringens_ can also worsen the impact of coccidiosis and NE in poultry [9].  
To reduce the economic losses resulting from NE and coccidiosis which cause weight reduction, decreased feed conversion efficiency, enhanced morbidity, and mortality associated with weakened digestion and absorption, various growth-promoting and disease-preventing in-feed antibiotics have been administered in commercial poultry production [10; 11; 12; 13]. However, with the potential concerns about the increasing antibiotic resistance in humans and the associated risk of antibiotic residues in animal meat products, most growth-promoting antibiotics have been regulated [14]. In recent years, several novel antibiotic alternative strategies have been developed to enhance animal production [15], and phytochemicals have been used as natural growth-promoters in the ruminants, swine, and poultry industries [16]. To this end, it is important that novel antibiotic alternatives, such as phytogenic extracts, or phytogenic feed additives, such as ginger, green tea, and onion peel extracts, are explored as in-feed antibiotics. While ginger has been reported to contain gingerol, shogaols, gingerdiol, and gingerdione [17], green tea consists of catechins, alkaloids, and polysaccharide [18], and onion peel contains quercetin and isorhamnetin [19; 20]. Overall, these phytogenic extracts have been shown to have characteristic bioactive constituents which exhibit antimicrobial, antioxidant, anti-inflammatory, immune-modulatory, and digestion-stimulating properties [21; 22].  
The objective of this study was to investigate the effect of phytogenic extracts such as ginger root extract (GRE), green tea extract caffeinated (GTEC), green tea extract decaffeinated (GTED), and onion peel extract combined (OPEC) on the activity of _C. perfringens_ toxins. Furthermore, the effects of these selected phytochemicals, especially green tea and ginger extracts, on _E. tenella_ sporozoites were investigated to develop phytogenic-based feed additives to replace antibiotics in promoting intestinal health and preventing NE and coccidiosis in broiler production.