## 2 Materials and Methods
### Meat Production
#### 3.1.1 Slaughter Traits (Carcass Weight and Quality, and Internal Organ Weights)
The PP- and low VitE (100 mg/kg)-supplemented animals had a greater polyunsaturated fatty acids (PUFA) content compared with the positive control group (only heat stress). In addition, lower natural drip loss was found in the PP- and VitE (200 mg/kg)-fed animals compared with the basal and low-VitE (100 mg/kg) diets [20]. In another similar trial, dietary supplementation with a combination of VitE (100 mg/kg) and PP (at 0.01 and 0.02%) increased (by 5.1 and 3.8%, respectively) broiler breast muscle pH at 15 h after slaughter in comparison with the basal diet, but not when compared with a diet containing VitE and low-quality oil [28]. On the other hand, the pH decreased (by 2.7%) 24 h after slaughter in poultry consuming the PP diet (at 0.02%) in comparison with the VitE (200 mg/kg) one [26]. Supplementation of PP had positive effects on color parameters. Birds in the PPE and PP groups had an improved L* value compared with the negative (by 3.5 and 5.0%, respectively) and positive control (by 3.7 and 5.2%, respectively) groups. Similarly, the L* value was higher in the PP group than in VitE groups (by 4.8%, on average). However, the other color parameters were not affected. With respect to the fatty acid composition of breast muscle (BM), dietary supplementation with PP alone or in combination with VitE did not exert a positive effect on PUFA, hypocholesterolemic fatty acids (DFAs), neutral and hypocholesterolemic/hypercholesterolic fatty acids ratio, or on the atherogenicity index, unlike VitE [28]. When broilers were fed experimental diets containing ochratoxin A and with the same doses of antioxidants given in the previous trial, PP and VitE were not effective in reducing the detrimental effect of the contaminated diet. The percentages of SFA and oxo-fatty acids (OFA) were, in fact, significantly higher, while those of PUFA, n-3 FA, and DFA were lower in the ochratoxin A-fed animals compared with those consuming the uncontaminated diet [15]. The dietary inclusion of OP (3% of the diet), during a 42-day trial, resulted in a lower L* value (by 4%) in broilers' PM than the inclusion of vitamin C (VitC; 1000 mg/kg of the diet) and VitE (200 mg/kg of the diet) [27]. The addition of HE (0.15% of the diet), compared with VitE, reduced the redness a* (by 15.9%) and b* (by 8.6%) [13]. Therefore, in these two previous studies, color was not improved by feeding PFA. The incorporation of PFA alone or in combination with VitE (0.02% of the diet, PP, or 0.01% + 100 mg/kg of VitE, PPE) in HS broiler diets induced a lower WHC compared with the positive HS control treatment [20]. Despite the greater PUFA content observed in the supplemented groups, lower concentrations of eicosadienoic acid (C20:2), arachidonic acid (C20:4), eicosapentanoic acid (C20:5), and docosapentanoic acid (C22:5) and greater proportions of n-6 fatty acids were observed compared with unsupplemented HS broilers [20]. Conversely, OO inclusion in two different diets (CSB, crude soybean oil diet; ASO, acidulated soybean oil soapstock) did not affect the proportions of SFA, MUFA, PUFA, and the PUFA/SFA ratio in broilers' BM compared with VitE (10 or 100 mg/kg) administration. However, the proportion of linolenic acid (C18:3) was higher in OO compared with the VitE-fed animals (38.4 and 44.4%, respectively) [29]. Supplementing the diet of broilers with oregano aqueous extract (OAE, 0.02% of the diet) did not produce any significant effects on the physicochemical, proximate, and fatty acid (including CLA isomers and PUFA n-3 content) composition of the BM, in comparison with those consuming the control (low VitE content) and the VitE diet (150 mg/kg) [30]. When SE was added to a broiler diet, an increase in the proportions of stearic acid (C18:0) (by 20.1%), arachidonic acid (20:4) (by 44.7%), DHA (C22:6 n-3) (by 59.6%), and n-3 PUFA was recorded in comparison with those fed the basal diet, but not with the VitE-fed ones [19].