## 3 Results and Discussion
### Influence of Hen Diet on Nutritional Profile and Physical Characteristics of Eggs
\begin{table}
\begin{tabular}{c c c c c c c} \hline  & & **Control** & **Week 1** & **Week 2** & **Week 3** & **Week 4** \\ \hline \multirow{4}{*}{**Synthetic**} & \multirow{2}{*}{**Synthetic**} & EPA + DHA (mg/100 g) & 52 \(\pm\) 4 \({}^{*}\) & 116 \(\pm\) 7 & 120 \(\pm\) 13 & 109 \(\pm\) 33 & 110 \(\pm\) 19 \\  & & EPA + DHA (mg/100 Kcal) & 37 \(\pm\) 3 \({}^{*}\) & 84 \(\pm\) 4 & 85 \(\pm\) 9 & 77 \(\pm\) 22 & 80 \(\pm\) 12 \\ \hline \multirow{4}{*}{**Synthetic**} & \multirow{2}{*}{**Synthetic**} & Lipids (\%) & 9.90 \(\pm\) 0.26 & 9.64 \(\pm\) 0.27 & 9.78 \(\pm\) 0.12 & 9.73 \(\pm\) 0.46 & 9.63 \(\pm\) 0.39 \\  & & Protein (\%) & 11.9 \(\pm\) 0.50 & 12.0 \(\pm\) 0.11 & 12.1 \(\pm\) 0.36 & 12.2 \(\pm\) 0.69 & 11.8 \(\pm\) 0.30 \\  & & Ash (\%) & 0.83 \(\pm\) 0.01 & 0.85 \(\pm\) 0.06 & 0.86 \(\pm\) 0.05 & 0.88 \(\pm\) 0.04 & 0.84 \(\pm\) 0.02 \\ \hline \multirow{4}{*}{**Synthetic**} & \multirow{2}{*}{**Synthetic**} & Egg weight (g) & 65.2 \(\pm\) 4.0 & 64.8 \(\pm\) 4.1 & 61.5 \(\pm\) 2.1 & 66.0 \(\pm\) 5.2 & 63.1 \(\pm\) 5.3 \\  & & Shell colour (\%) & 28.4 \(\pm\) 7.2 & 26.2 \(\pm\) 8.5 & 28.1 \(\pm\) 5.0 & 26.4 \(\pm\) 4.1 & 31.7 \(\pm\) 4.4 \\  & & Quality (UH) & 80.8 \(\pm\) 7.9 \({}^{*}\) & 84.7 \(\pm\) 8.9 \({}^{*,\#}\) & 88.3 \(\pm\) 6.3 \({}^{*,\#}\) & 88.8 \(\pm\) 5.5 \({}^{\#}\) & 82.1 \(\pm\) 8.6 \({}^{*,\#}\) \\  & & Shell thickness (\(\mu\)m) & 372 \(\pm\) 19 & 372 \(\pm\) 10 & 378 \(\pm\) 29 & 361 \(\pm\) 24 & 371 \(\pm\) 27 \\ \hline \end{tabular} For each parameter (same row), distinct symbols (\({}^{*}\), \({}^{\#}\)) mean statistically significant differences (\(p\) < 0.05) between groups (N = 5 for fatty acids and nutritional profile data; N = 12 for physical parameters data). DHA—docosahexaenoicenoic acid  
\end{table} 
Table 2: Physical parameters and nutritional profile of eggs from hens fed with supplemented diet with 3% of _Nannochloropsis ocaanica_ during 4 weeks of trial. Figure 1: ALA, EPA and DHA contents (mg/100 g) in eggs from hens fed with _Nannochloropsis ocaanica_ supplemented diet during the 4 weeks of trial. For the same FA, \({}^{*}\) means statistically significant differences (\(p\) < 0.05) (N = 5). [PERSON] et al. [32] compared four distinct microalgae and observed an increase in DHA and EPA, regardless of the species supplied to hen feed. Higher efficiency of n-3 PUFA enrichment was attained with _Phaeodactylum tricornutum_ and _Isochrysis galbuna_ in comparison to _Nantochloroposis oculata_. An increase in ALA content was only observed with _Chlorella fusca_ supplemented feed, which reflects the high amount of this fatty acid in its composition. Another study focused on the supplementation of hens feed with the microalgal _Isochrysis galbuna_ in comparison with other sources of n-3 PUFA (flaxseed, fish oil, and DHA gold) for eggs enrichment. This microalga shown to be more efficient in the increase of EPA and DHA levels than flaxseed, which was mainly responsible for ALA improvement. Comparatively to fish oil and DHA Gold, _I. galbuna_ was less efficient for eggs supplementation, due to differences in both bio-accessibility and n-3 PUFA profile [43]. Concerning the physical parameters, statistically significant differences were observed in yolk colour that became more orange right at the end of week 1 (ANOVA, Dunnett's test, F(4.55) = 6.237, \(p\)-value \(<\) 0.001; Figure 3). The shift towards higher values of Roche scale, as result of microalgae feed supplementation, was also reported by other authors [32; 41; 42]. The yolk colour intensification is associated to carotenes and xanthophyll migration from feed to eggs [10; 32; 42; 44]. _Nantochloroposis_ species are rich in carotenoids, flavonoids, and other phenolic compounds which have well-documented antioxidant activity [23; 45]. The migration of these compounds from supplemented feed also improves the nutritional composition of eggs and its oxidative stability [10; 46].