## 3 Results
### Nutritional Egg Quality Parameters  
Table 6 presents the effect of dietary chlorella and spirulina powder on laying hens' egg nutrients and external/internal quality parameters. The microalgae dietary supplementation influenced the nutritional egg quality positively. The \(\beta\)-carotene concentration registered a highly significant increase (\(p\) < 0.0001) in experimental diets, the results being positively correlated with the concentration of chlorophylls \(a\) and \(b\) and caroten of both dietary microalgae. The same observation could be noted for both antioxidant capacity expressed as DPPH% inhibition (\(p\) < 0.0001) and \(\upmu\)M Trolox (\(p\) < 0.033).  
Concerning the egg quality parameters, no effects (\(p\) > 0.05) of chlorella or spirulina powder were observed on egg weight or its components (albumen, yolk, and shell). The album pH was influenced by the presence of algae compared to the CON diet: lower value for chlorella diet, and higher value for spirulina diet. The yolk pH and the albumen height were not influenced by the dietary treatment. The Haugh unit, the most widely accepted  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Parameters**} & \multicolumn{4}{c}{**Dietary Treatments**} & \multirow{2}{*}{**SEM**} & \multirow{2}{*}{**\(p\)-Value**} \\ \cline{2-2} \cline{4-5}  & **CON** & & **CV2\%** & & \\ \hline Nutrition quality of egg yolk & & & & \\ \hline \(\beta\)-carotene, (\(\upmu\)g/g) & 30.77 b  & 38.82 a  & 38.25 a  & 0.432 & \(<\)0.0001 \\ Total polyphenols (mg/g GAE) & 0.534 & 0.598 & 0.574 & 0.027 & 0.271 \\ Antioxidant capacity (DPPH% inhibition) & 16.84 b  & 25.14 a  & 28.15 a  & 0.869 & \(<\)0.0001 \\ Antioxidant capacity (uM Trolox) & 0.74 b  & 0.79 a  & 0.82 a  & 0.019 & 0.033 \\ \hline External and internal egg quality parameters & & & & & \\ \hline Egg weight (g), of which: & 61.28 & 61.53 & 61.82 & 0.389 & 0.617 \\ albumen white (g) & 37.00 & 37.76 & 37.38 & 0.352 & 0.320 \\ egg yolk (g) & 16.37 & 15.65 & 16.26 & 0.242 & 0.087 \\ eggshell (g) & 7.91 & 8.12 & 8.17 & 0.137 & 0.358 \\ Albumen pH (value) & 8.62 ab  & 8.44 b  & 8.80 a  & 0.069 & 0.002 \\ Yolk pH (value) & 6.51 & 6.38 & 6.46 & 0.093 & 0.625 \\ t\({}^{\circ}\) albumen (\({}^{\circ}\)C) & 19.10 a  & 18.57 ab  & 17.79 b  & 0.258 & 0.003 \\ t\({}^{\circ}\) yolk (\({}^{\circ}\)C) & 19.99 a  & 19.12 b  & 19.92 a  & 0.134 & 0.011 \\ White height, mm & 10.96 & 11.74 & 11.48 & 0.292 & 0.168 \\ Haugh units (value) & 102.92 & 106.04 & 104.82 & 1.150 & 0.163 \\ Yolk color, (value) & 4.06 c  & 8.11 b  & 11.06 a  & 0.113 & \(<\)0.0001 \\ \hline \hline \end{tabular} Where: CON, conventional diet; CV2%, conventional diet supplemented with 2% chlorella powder; SP2%, conventional diet supplemented with 2% spirulina powder; \(n\) = 6 samples per group (3 eggs/ sample); SEM, standard error of the mean. ab Mean values within a row having different letters are significantly different at \(p\)\(\leq\) 0.05.  
\end{table}
Table 5: Apparent nutrient digestibility (%) of laying hens fed with _Ch. vulgaris_ and _Sp. platensis_ powder diets.  
indicator of internal egg quality, had an increasing tendency in eggs obtained from algae supplementation diets, especially for the chlorella diet. The egg yolk color in groups fed diets with chlorella or spirulina were significantly higher (\(p<0.0001\)) compared to the CON diet.