Quail egg yolk (Coturnix coturnix japonica) enriched with omega-3 fatty acids Walber Arantes da Silva a , Alberto Henrique Naiverti Elias a , Juliana Aparecida Aricetti a , Ma ´ rcia Izumi Sakamoto b , Alice Eiko Murakami b , Sandra Terezinha Marques Gomes a , Jesuı ´ Vergı ´lio Visentainer a , Nilson Evela ´ zio de Souza a , Makoto Matsushita a, * a Department of Chemistry, State University of Maringa, Avenida Colombo, 5790, 087020900, Maringa, Parana State, Brazil b Department of Animal Science, State University of Maringa, Avenida Colombo, 5790, 087020900, Maringa, Parana State, Brazil article info Article history: Received 23 May 2007 Received in revised form 6 August 2008 Accepted 26 August 2008 Keywords: Omega-3 Egg yolk Flaxseed Quail Fatty acid Cholesterol abstract This experiment was carried out with 58-week old laying quails (Coturnix coturnix japonica) assigned to four treatment groups with eight quails per replication in six repetitions in a completely randomized design. The treatments consisted of diets with different levels of flaxseed (0, 1.5, 3.0, and 5.0%). The amounts of cholesterol and total lipids and the fatty acid composition of quail egg yolk were determined in four 21-day cycles. No difference was found in cholesterol levels between the four treatments and the four cycles. The increased ingestion of linolenic acid (LNA) in diet reduced the formation of arachidonic acid (AA) significantly. The 3.0 and 5.0% treatment groups presented a reduction in total saturated fatty acids (TSFA) with the increase in percent flaxseed in feed comparatively to the control value. The n-3 fatty acid level was high in all treatments when compared to that of the control group. The n-6/n-3 ratio decreased from 21.30 (control) to 4.52 (5.0%), which is a better value from the nutritional viewpoint. Ó 2008 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved. 1. Introduction Recent studies have demonstrated the improvement of the lipidic quality of egg yolks of laying poultry with diets supple- mented with vegetable oils, horse fat, or feeds with microalgae with a high proportion of n-3 PUFA (Abril & Barclay, 1998; Cabrera et al., 2005; Fredriksson, Elwinger, & Pickova, 2006; Sim, Cherian, & Jiang, 1992). Linoleic acid (LA; 18:2n-6) and alpha-linoleic (LNA; 18:3n-3) and their long chain derivatives are important components of animal and plant cell membranes. The conversion of dietary LNA into EPA (eicosapentaenoic acid; 20:5n-3) is limited because the efficacy of the synthesis of n-3 long chain polyunsaturated fatty acid (LC-PUFA) decreases down the LNA conversion cascade. The synthesis of DHA (docosahexaenoic acid; 22:6n-3) from LNA is even more restricted than that of EPA. It is generally assumed that linoleic acid reduces EPA synthesis because of the competition between LNA and LA for the common desaturation and elongation enzymes (Simopoulos, Leaf, & Salem, 2000). Other dietary factors such as the polyunsaturated:saturated fat ratio, the amount of dietary EPA and trans fatty acids consumed, and the amount and type of proteins consumed have all been implicated as affecting this conversion (Layne et al., 1996; Sugano & Ikeda, 1996). The conversion efficiency and intervenient factors may have an important implication for public health (Harper, Edwards, DeFilipis, & Jacobson, 2006). DHA is important for biological membranes, the retina, the cerebral cortex, nervous tissues, the testicles, blood platelets, and EPA due to its effect on arteries (antithrombotic and anti-inflammatory) resulting from the metabolism of eicosanoids (biological molecules that act as signals and messengers) (Mueller & Talbert, 1988). Fish is one of the best known sources of n-3 PUFA in human diet, as it is rich in EPA and DHA fatty acids. Another source is oil seeds, particularly flaxseed, which has a high LNA content (50–55%) (Chen, Ratnayake, & Cunnane, 1994). Several studies have demonstrated the incorporation of n-3 PUFA to yolk by the addition of flaxseed to poultry feed (Milinsk, Murakami, Gomes, Matsushita, & Souza 2003). The incorporation of n-3 PUFA promotes a qualitative change in the yolk fatty acid profile, reducing the n-6/n-3 ratio to a more beneficial level with regards to the human nutritional needs (Simopoulos, 1998). This effect is due to the transformation of C-18 PUFAs (LNA and LA) into their metabolites LC-PUFA (Long Chain PUFA): EPA and DHA, which have been demonstrated to be valuable in the treatment of cardiovas- cular diseases (Simopoulos, 2000). Recent studies have shown that the nutritional quality of fat in food products should be evaluated by taking into account not only their saturated (SFA), monounsaturated (MUFA), and poly- unsaturated (PUFA) fatty acid contents, but also their cholesterol levels. Eggs are a major source of dietary cholesterol and consumer concerns about the association of cholesterol with coronary heart * Corresponding author. Tel.: þ55 44 3261 3655; fax: þ55 44 3261 4105. E-mail address: mmakoto@uem.br (M. Matsushita). Contents lists available at ScienceDirect LWT - Food Science and Technology journal homepage: www.elsevier.com/locate/lwt 0023-6438/$34.00 Ó 2008 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.lwt.2008.08.005 LWT - Food Science and Technology 42 (2009) 660–663