Olive oil contains a variety of antioxidants, including vitamin E. Its consumption protects against oxidative stress, which is involved in many pathological conditions, affecting animals’ development and their general welfare. The present study aimed to investigate the effect of olive paste flour (OPF) on the antioxidant status and performance of broiler chickens raised in field conditions. Total of 18.000 broilers was randomly allocated in equal numbers in two poultry houses. The chickens were grouped according to their diet as follows: Control group: chickens fed commercial poultry feed, and OPF group: chickens fed control dietsin the starter period, but they got a supplement of OPF in grower, and finisher 1 and 2periods, respectively. The birds were raised under identical field conditions (ventilation, vaccination, lighting, etc.). Antioxidant status was assessed by measuring the concentration of vitamin E in plasma, as well as the total antioxidant capacity (TAC) in plasma and muscle tissue. According to the statistical analysis of the results, the addition of OPF to chickens’ diet significantly enhanced plasma α-tocopherol concentration (p≤0.05). TAC did not show any significant differences in chicken plasma nor muscle tissue(p>0.05).Feed intake (FI) was higher in OPF group, while Body weight (BW) was lower. Liveability was similar for the two groups. The feed conversion ratio (FCR) was higher, and the European production efficiency factor (EPEF) was lower in broilers of the OPF group compared to those of the control group.Samples of roasted breast from chickens of both groups were used for organoleptic characteristics evaluation. Results showed that samples of the OPF group smelled more intensely and were more tasteful than those of the control group.However, other organoleptic characteristics did not differ. In conclusion, the results demonstrated that although the addition of OPF to chickens’ diet can cause growth retardation, it can significantly increase the plasma α-tocopherol concentration. Further studies are needed to optimize the concentration of OPF in poultry feed in order to avoid growth retardation or even to promote growth in broiler chicks.

Tyrosine radicals are notoriously short-lived/unstable in solution, while they present an impressive degree of stability and versatility in bioenzymes. Herein, we have developed a library of hybrid biomimetic materials (HBMs), which consists of tyrosine-containing oligopeptides covalently grafted on SiO 2 nanoparticles, and studied the formation, lifetime, and redox properties of tyrosyl radicals. Using electron paramagnetic resonance spectroscopy, we have studied the radical-spin distribution as a probe of the local microenvironment of the tyrosyl radicals in the HBMs. We find that the lifetime of the tyrosyl radical can be enhanced by up to 6 times, by adjusting three factors, namely, a proximal histidine, the length of the oligopeptide, and the interface with the SiO 2 nanomatrix. This is shown to be correlated to a significant lowering of E 1/2 from +736 mV, in free tyrosine, to +548 mV in the {12-peptide}@SiO 2 material. Moreover, we show that grafting on SiO 2 lowers the E 1/2 of tyrosine radicals by ∼50 mV in all oligopeptides. Analysis of the spin-distribution by EPR reveals that the positioning of a histidine at a H-bonding distance from the tyrosine further favors tyrosine radical stabilization.

Peptide analogs/conjugates Abbreviation Ac-(Lys-Aib-Cys) 4 -NH 2 CPSOC CF-Ahx-[Lys-Aib-Cys(S-CH 2 CONH 2 )] 4 -NH 2 CF-Ahx-CPSOC(S-CH 2 CONH 2 ) CF-G 48 RKKRRQRRRPPQ 60 -Cys (CH 2 CONH 2 )-NH 2 CF-Tat 48-60 -Cys (CH 2 CONH 2 ) CF-Ahx-S 158 ALTQKGLKNVFDEA 172 -NH 2 CF-Ahx-Cdc42 158-172 CF-Ahx-[Lys-Aib-Cys(S-CH 2 CO-V 181 IKKSKK 187 -NH 2 )] 4 -NH 2 CF-Ahx-CPSOC(S-CH 2 CO-Cdc42 181-187 ) CF-Ahx-[Lys-Aib-Cys(S-CH 2 CO-I 173 VAALEPPVIKKSKK 187 -NH 2 )] 4 -NH 2 CF-Ahx-CPSOC(S-CH 2 CO-Cdc42 173-187

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