In order to investigate the effects of omega (n) 3 fatty acids on egg quality a group-control trial was organized. Trial lasted 40 days and was performed in production conditions. Total number of 1264 laying hens of Lohman Brown classic provenience were used and randomly allotted into one of four groups by 316 hens each (C-control, I experimental, II experimental and III experimental). All groups of hens were fed diets of standard ingredients and chemical composition, while feed of I, II and III experimental group of hens was supplemented with micro algae Schizochytrium spp. (DHA Gold?, Martek, USA) as a source of n- 3 fatty acids in amount of 0.5, 0.7 and 1.0 % respectively. In order to investigate the influence of micro algae Schizochytrium spp. feed supplementation on egg quality, from the aspect of content and ratio of fatty acids, random egg samples (n=10) were taken at the 10th, 20th and 40th day of the trial from each group. Egg yolk fatty acid content was determined by gas chromatography on Varian 1400 with flame ionization detector (FID detector) (on a packed column 20% LAC-3R-728 Chromosorb WAW 80-100 mesh). Significant differences in egg yolk fatty acid content as well as their ratio were determined between treatment groups. Positive influence of supplemented micro algae preparation was observed. Highest content of n-3 poly unsaturated fatty acids (PUFA n-3) was determined in egg yolks of III experimental group while lowest content was determined in egg yolks of control group of hens. Micro algae feed supplementation, at the end of the trial period, positively affected egg yolk PUFA n-6/PUFA n-3 ratio, since determined ratio of 4.24 in III experimental group was more desirable than 12.27 determined in a control group. Marine algae (Schizochytrium spp.) feed supplementation in laying hens in amounts above 0.5% significantly affected egg yolk fatty acid composition as well as ratio of n-6/n-3 PUFA. These findings support its use from nutritive, medical and economic point of view.

A group-control experiment for a period of 45 days was conducted in order to determine the effects of use of ω-3 fatty acids on the production and economic results of laying hens. A total of 1264 Lohmann Brown layers were randomly devided into 4 experimental treatments with 79 replicates (4 per cage, 316 hens per treatment). The first group was fed complete feed mixture for laying hens with standard raw material and chemical composition. The feed mixtures for treatments 2., 3. and 4. were supplemented with ω-3 fatty acids. The source of ω-3 fatty acids was a microalgae Schizochytrium spp., commercial product "DHA Gold" (Martek, USA) in quantities of 0.5, 0.7 and 1.0%, respectively. The use of ω-3 PUFA supplement in higher inclusion rates, had a positive influence on the laying intensity, significantly higher (p <0.01) in the experimental groups supplemented in the amount of 0.7 and 1.0%. Layers of all experimental groups fed supplemented feed mixtures had lower average egg weights (68.1, 68.7 and 68.4 g) compared to the control group (68.8 g). However, supplementation with higher inclusion rates of ω-3 product resulted in higher total egg mass during the experiment (743 and 764 kg) in the third and fourth experimental groups, compared to the control group (691.9 kg). Experimental groups with a higher inclusion of ω-3 PUFA (0.7 and 1.0%), achieved higher daily consumption of 0.16% and 0.51% in comparison to the control group, but the best feed conversion (2.38 and 2.32), while supplementation in the amount of 0.5% resulted in the weakest conversion in the experimental group 2 (2.63). The lowest feed cost per produced egg was achieved by the control group fed complete, unsupplemented feed. Using supplemented feed with addition of ω-3 PUFA -DHA above the 0.5%, a significant difference was observed regarding the productivity of laying hens.