## 3 Results and Discussion
### Lipid Oxidation
Hexanal values, reported in Table 4, showed trends only partially similar to those of TBARS. The detected hexanal values were similar in all the experimental groups and, except for the VE100 dietary group, only slightly affected by dietary treatment. In the VE100 dietary group, on the other hand, the hexanal content was significantly lower, approximately 35%, than that in the CTRL group from t0 to t4. The absence of effect of VE at concentrations above 100, corresponding to the amount of 4.22 mg/kg in meat, reveals that an optimal intake of VE is necessary for the best antioxidant effect, as also observed by other authors, who found better protective effects at concentrations below 200 [36; 37; 38; 10; 38]. The significant decrease in hexanal content at t4 in the CTRL and VE200 dietary groups could suggest that lipid oxidation had entered a termination stage as recently suggested [39]. The data regarding the VE dietary groups seemed to confirm the protective effect of VE on lipid oxidative stability found in other studies [4; 5; 40; 41] in which the reduced oxidation was sometimes also accompanied by an increase in VE content in the muscle [5; 19; 40]. The effects described for VE usually referred to a specific action on lipid oxidation; in fact, due to its lipophilic structure, VE is considered to be a potent, and probably the most important, lipophilic antioxidant [42]. On the other hand, the hexanal values found for EcoE groups, which were not different from those for the control group, do not seem to confirm a specific protective effect of the dietary supplementation with Se on lipid oxidation. [PERSON] et al. [5] have recently found a protective effect of organic Se on oxidative stability, with enriched Se content in _Longissimus lomborum_ and _Biceps femoris_ rabbit muscles (Table 2). A similar protective effect was also observed in some other studies involving rabbits [15; 17] and other species [12; 43; 13]. In particular, [PERSON] et al. [15] demonstrated that dietary organic Se supplementation, from 0 to 2.5 mg/kg, increases the Se content of rabbit meat and supplementation with 0.5 mg/kg Se improved oxidative stability, while at the \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multicolumn{2}{c}{**Dietary Groups**} & \multicolumn{5}{c}{**Hexanal (mg Hexanal/kg Product)**} \\ \cline{3-8} \multicolumn{2}{c}{} & **CTRL** & **VE100** & **VE200** & **EcoE100** & **EcoE200** \\ \hline \multirow{4}{*}{Storage time} & t0 & 0.477 \({}^{\text{ax}}\)\(\pm\) 0.026 & 0.154 \({}^{\text{by}}\)\(\pm\) 0.009 & 0.571 \({}^{\text{ax}}\)\(\pm\) 0.009 & 0.514 \({}^{\text{ax}}\)\(\pm\) 0.014 & 0.573 \({}^{\text{ax}}\)\(\pm\) 0.094 \\  & t1 & 0.535 \({}^{\text{ax}}\)\(\pm\) 0.103 & 0.255 \({}^{\text{by}}\)\(\pm\) 0.048 & 0.450 \({}^{\text{ax}}\)\(\pm\) 0.056 & 0.404 \({}^{\text{cy}}\)\(\pm\) 0.148 & 0.585 \({}^{\text{ax}}\)\(\pm\) 0.013 \\  & t2 & 0.555 \({}^{\text{ax}}\)\(\pm\) 0.080 & 0.165 \({}^{\text{by}}\)\(\pm\) 0.044 & 0.531 \({}^{\text{ax}}\)\(\pm\) 0.081 & 0.536 \({}^{\text{ax}}\)\(\pm\) 0.044 & 0.618 \({}^{\text{ax}}\)\(\pm\) 0.033 \\  & t4 & 0.193 \({}^{\text{by}}\)\(\pm\) 0.006 & 0.238 \({}^{\text{by}}\)\(\pm\) 0.037 & 0.287 \({}^{\text{by}}\)\(\pm\) 0.062 & 0.913 \({}^{\text{dz}}\)\(\pm\) 0.035 & 0.605 \({}^{\text{ax}}\)\(\pm\) 0.009 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The effects of dietary supplementation with \(\alpha\)-tocopherol acetate (VE) or Economics\({}^{\text{ETM}}\) (EcoE) and storage time on the hexanal content (mg/kg product) of packaged rabbit hamburgers. highest doses, a prooxidant effect was observed. Similarly, [PERSON] et al. [17] found that diet supplemented with 10% olive leaves enriched in Se (2.17 mg of Se per kg of dried leaves) positively affected the oxidative status of rabbit meat, reducing the TBARS value and carbonyl derivatives of proteins. An antioxidant effect was found in rabbits also with the supplementation of Nano-Se or sodium selenite [16].