## 2 Materials and Methods
#### 3.1.1 Feed Intake  
The dietary supplementation of broilers with grape pomace (GP; 0.5% to 6% of the diet) in comparison with VitE (200 mg/kg of the diet) or a basal diet (no VitE added) for 21 days did not affect broilers' feed intake (FI) [14; 15]. Similarly, the dietary inclusion of fermented and unfermented grape skin (FGS and UGS, respectively; 6% of the diet) for 21 days did not affect broilers' average daily feed intake (ADFI) in comparison with a negative (no VitE) and a positive (200 mg/kg of VitE) control [16]. Similar results were found when comparing VitE (200 mg/kg) with antioxidant compounds (2.5% of rosehip, chokeberry pomace, or nettle separately) supplementation for 28 days [17] or rosemary oil (RO; 0.010%, 0.015%, and 0.020% of the diet) supplementation for 42 days [18] or feeding rosemary leaves (RL; 2.5% of the diet) for 28 days [17]. The FI was also not affected when coreflower extract (CE, 0.056% of the diet), thyme extract (TE, 0.056% of the diet), sage extract (SE, 0.056% of the diet), marigold xanthophyll (MX, 0.02% of the diet), synthetic antioxidants (0.00486% of the diet), or \(\beta\)-apo-8-carotene acid ethylester (0.004% of the diet) were separately administered compared with VitE (150 mg/kg) during a 20 day trial [19]. When SE was added to laying hens diet (2.5% of the diet), no significant effects on FI compared to control (deficient VitE diet) or to VitE groups (30 mg/kg of the diet) were reported [20]. The dietary supplementation with oregano oil (OO; 0.01% [21; 22] and 0.02% of the diet [21]) compared with VitE (included at 200 mg/kg [21] and 10 or 100 mg/kg [22] of the diet) for 42 days did not affect broilers' FI. The inclusion of dehydrated oregano plant (OP; 0.5% and 1%) in addition to VitE (170 mg/kg) for 28 days compared with VitE (170 mg/kg) or antibiotic (Flavomycin, 0.0004% of the diet; and Lasalocid, 0.0075% of the diet) enriched diets also showed no effect in turkeys [23]. Supplementation with different levels of RO (0.015% or 0.030% of the diet) or a combination of RO with OO (both at 0.0075% and 0.0150% of the diet, respectively) during a 42 day trial did not affect broilers' FI compared with VitE (200 mg/kg) [24]. In addition, no significant variations in FI were reported when broilers were supplemented for 42 days with OO, RO, or fennel volatile oil (FVO) (each at 0.01% of the diet) or with a mixture of them (VOM, 0.01 to 0.4%) [25]. Moreover, olive leaf extract (OLE) dietary supplementation (0.2% and 0.4% of the diet) did not affect FI in broilers reared under heat stress (HS) during a 14 day period compared with control and VitE treatments [26]. On the contrary, broilers fed thyme oil (TO; 0.01% and 0.02% of the diet) exhibited a higher FI (by 3.7% on average) compared with those receiving only a basal diet (in which VitE -40 mg/kg- was included in a premix). A similar increase in FI (2.0% on average) was observed in comparison with the VitE (200 mg/kg) supplemented group [27]. Nevertheless, in broilers, the dietary inclusion of rosemary powder (RPO; 1% of the diet) compared with VitE (200 mg/kg) lowered the FI (by 4.3%) in a 42 days feeding trial [28]. In laying hens, the dietary addition of rosemary plant (RP; 0.5% and 1% of the diet) [29; 30], OP (0.5% of the diet) [29], or safron plant (SP; 2% of the diet) [29] compared with VitE (200 mg/kg) did not modify FI. Moreover, Roselle calyx (_Hibiscus sudbarifa_ [PERSON]) powder (RCP; 2% and 4% of the diet) or its extract (RCE; 1% and 2% of the diet) did not affect FI in laying hens throughout an 8 weeks trial compared with VitE (250 mg/kg) [31]. No effect was found on FI between anise seed (AS; 1% and 2% of the diet) and VitE (30, 600, or 300 mg/kg of diet) fed Japanese quails [32]. Only a study in laying hens demonstrated a reduction of FI (by 6%) when green tea extract (GTE; 1.5% of the diet) compared with VitE (200 mg/kg) was administered [33].