Uticaj primene različitih izvora prirodnih pigmenata na boju žumanca i ko-ekstrudata na bazi semena lana, lanika i konoplje na profil masnih kiselina u jajima / Effects of different sources of natural pigments inclusion on the egg yolk colour and flaxseed

The aim of this doctoral dissertation, which consisted of two parts, was to show the possibility of replacing synthetic pigments, which are nowadays used in conventional egg production, with natural sources of pigments and their influence on the colour of the yolk, as well as the possibility of changing the nutritive egg profile by adding co-extruded flax, camelina seed and hempseed rich in omega-3 fatty acids in laying hens nutrition. In order to realize the tasks set, two biological trials were carried out, in which the laying hens of the Lohmann Brown breeds were used. In the first biological trial, according to the experimental design the laying hens were divided into 12 treatments, ten experimental and two controls, which differed in the source of added pigments. Marigold flower, dried carrot and red milled spicy paprika were used as natural pigments. Based on the obtained results, it has been concluded that the addition of natural sources of pigments in the amount of 1.5% does not affect the technological parameters of egg quality. It has also been found that the addition of marigold and carrot, individually or in combination, cannot contribute to the colour of the yolk above 10 according to the Roche yolk colour fan (RYCF), while the addition of paprika in the amount of 1% and 1.5% contributes to the colour of the yolk greater than 14 RYCF. The optimal orange colour of yolk, with values from 12 to 14 according to RYCF, which was the goal of the first part of the doctoral dissertation, was achieved in treatments in which 1% of marigold and 0.5% of paprika, 1% of carrot and 0.5% of paprika, as well as 0.5% of all three components were added in laying hens diets. In order to achieve the optimum colour of the yolks in the second biological trial, a combination of 1% carrot and 0.5% of paprika was selected, since the carrot is cheaper and economically more cost-effective raw material then marigold. In the second biological trial, according to the experimental design, laying hens were divided into 8 treatments, six experimental and two controls, which differed in the source and amount of added fat (3% and 5%), as well as in the source of pigments (synthetic and natural). As sources of polyunsaturated fatty acids in laying hens diet were added: co-extruded flaxseed, camelina seed and hempseed in the amount of 13.5% and 22.5% of flax, 16.6% and 27.6% of camelina seed and 18.4% and 30.7% of hempseed. Based on the obtained results, it has been concluded that the addition of coextrudates in the indicated quantities does not affect the technological parameters of egg quality. The optimal colour of the yolk, with values ranging from 12.50 to 13.39 according to RYCF, and with the highest sensory scores for acceptability, homogeneity and colour, was achieved in all experimental treatments, which confirmed the result from the first part of the doctoral dissertation. The most important result, from the aspect of the nutritional value of the yolk, achieved by the addition of co-extruded flaxseed, camelina seed and hempseed in laying hens diet, is a decrease in the total content of saturated fatty acids (SFA), and the increase in the content of the desired omega-3 polyunsaturated fatty acids: α-linolenic acids (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), as well as an increase in total tocopherol content. With the addition of co-extrudates in laying hens diets, a much better ratio of ω-6/ω-3 fatty acids in yolks has been achieved. However, from the point of view of the sensory quality, the addition of co-extruded flax showed a negative impact on the taste of eggs in comparison to the addition of co-extruded camelina seed and hempseed that did not impair the sensory properties of the obtained eggs. Based on the obtained results, it can be concluded that with the addition of selected combinations of natural sources of pigments, as well as selected sources of omega fatty acids, functional eggs can be designed which will have the desired colour of the yolk, increased content of omega - 3 fatty acids without the impairment of the eggs sensory profile.