1. Stevanović ZD, Bošnjak-Neumüller J, Pajić-Lijaković I, et al. Essential oils as feed additives-future perspectives. Molecules 2018; 23(7): 1717. doi: 10.3390/molecules23071717.
2. Gao Z, Zhang J, Li F, et al. Effect of oils in feed on the production performance and egg quality of laying hens. Animals (Basel) 2021; 11(12): 3482. doi: 10.3390/ ani11123482.
3. Rouhanipour H, Sharifi SD, Irajian G, et al. The effect of adding L-carnitine to omega-3 fatty acid diets on productive performance, oxidative stability, cholesterol content, and yolk fatty acid profiles in laying hens. Poult Sci 2022; 101(11): 102106. doi: 10.1016/ j.psj.2022.102106.
4. Kartal M, Kurucu S, Aslan S, et al. Comparison of ω-3 fatty acids by GC-MS in frequently consumed fish and fish oil preparations on the Turkish market. Fabad J Pharm Sci 2003; 28: 201-205.
5. Mason RP, Libby P, Bhatt DL. Emerging mechanisms of cardiovascular protection for the omega-3 fatty acid eicosapentaenoic acid. Arterioscler Thromb Vasc Biol 2020; 40(5): 1135-1147.
6. Zolfaghari H, Jafarian K, Iraj B, et al. The role of omega-3 fatty acids on the prevention and treatment of nonalcoholic fatty liver disease: a review of published papers. JIMS 2014; 32(276): 243-255.
7. Yi D, Zeng S, Guo Y. A diet rich in n-3 polyunsaturated fatty acids reduced prostaglandin biosynthesis, ovulation rate, and litter size in mice. Theriogenology 2012; 78(1): 28-38.
8. Khan SU, Lone AN, Khan MS, et al. Effect of omega-3 fatty acids on cardiovascular outcomes: a systematic review and meta-analysis. EClinicalMedicine 2021; 38: 100997. doi: 10.1016/j.eclinm.2021.100997.
9. Baucells MD, Crespo N, Barroeta AC, et al. Incorporation of different polyunsaturated fatty acids into eggs. Poult Sci 2000; 79(1): 51-59.
10. Dong XF, Liu S, Tong JM. Comparative effect of dietary soybean oil, fish oil, and coconut oil on performance, egg quality and some blood parameters in laying hens. Poult Sci 2018; 97(7): 2460-2472.
11. Wiseman J, Powles J, Salvador F. Comparison between pigs and poultry in the prediction of the dietary energy value of fats. Anim Feed Sci Technol 1998; 71(1-2): 1-9.
12. Al-Shammari KIA, Zamil SJ, Batkowska J. The anti-oxidative influence of dietary creatine monohydrate and L-carnitine on laying performance, egg quality, ileal microbiota, blood biochemistry, and redox status of stressed laying quails. Poult Sci 2024; 103(1): 103166. doi: 10.1016/j.psj.2023.103166.
13. Elkomy A, Abdelhiee EY, Fadl SE, et al. L-carnitine mitigates oxidative stress and disorganization of cytoskeleton intermediate filaments in cisplatin-induced hepato-renal toxicity in rats. Front Pharmacol 2020; 11: 574441. doi: 10.3389/fphar.2020.574441.
14. Bahrampour H, Mohammadzadeh S, Amiri M. Impact of dietary L-carnitine supplementation on blood parameters and duodenal alterations in laying hens at the end of production. Tissue Cell 2024; 91: 102585. doi: 10.1016/j.tice.2024.102585.
15. Peebles ED, Kidd MT, McDaniel CD, et al. Effects of breeder hen age and dietary L-carnitine on progeny embryogenesis. Br Poult Sci 2007; 48(3): 299-307.
16. Golzar Adabi S, Cooper RG, Ceylan N, et al. L-carnitine and its functional effects in poultry nutrition. J World’s Poult Sci 2011; 67(02): 277-296.
17. Kalaiselvi T, Panneerselvam C. Effect of L-carnitine on the status of lipid peroxidation and antioxidants in aging rats. J Nutr Biochem 1998; 9(10): 575-581.
18. Chatzifotis S, Takeuchi T, Seikai T. The effect of dietary L-carnitine on growth performance and lipid composition in red sea bream fingerlings. Fish Sci 1995; 61(6): 1004-1008.
19. Hy-Line W36. Management guide. Available at: www.hyline.com/filesimages/Hy-Line-Products/Hy-Line-Product-PDFs/W-36/36%20COM%20ENG.pdf. Accessed May 7, 2026.
20. Ebrahimi M, Chaparabad HG, Al-Moussawi ISM, et al. Thyme plant powder (Thymus vulgaris) improves the production performance of laying hens by affecting ovarian follicles. Trop Anim Sci J 2025; 48(3): 231-240.
21. Haugh RR. The Haugh unit for measuring egg quality. US Egg Poult Mag 1937; 43: 552-555 and 572-573.
22. Funk EM. The relation of the yolk index determined in natural position to the yolk index as determined after separating the yolk from the albumen. Poult Sci 1948; 27(3): 367.
23. Kralik G, Kralik Z, Grčević M, et al. Fatty acid profile of eggs produced by laying hens fed diets containing different shares of fish oil. Poult Sci 2021; 100(10): 101379. doi: 10.1016/j.psj.2021.101379.
24. Alagawany M, Elnesr SS, Farag MR, et al. Omega-3 and omega-6 fatty acids in poultry nutrition: effect on production performance and health. Animals (Basel) 2019; 9(8): 573. doi: 10.3390/ani9080573.
25. Bozkurt M, Çabuk M, Alçiçek A. Effect of dietary fat type on broiler breeder performance and hatching egg characteristics. J Appl Poult Res 2008; 17(1): 47-53.
26. Shahryari M, Tabeidian SA, Shahraki AD, et al. Using soybean acid oil or its calcium salt as the energy source for broiler chickens: effects on growth performance, carcass traits, intestinal morphology, nutrient digestibility, and immune responses. Anim Feed Sci Technol 2021; 276: 114919. doi: 10.1016/j.anifeedsci. 2021.114919.
27. Kazemi-Fard M, Yousefi S, Dirandeh E, et al. Effect of different levels of L-carnitine on the productive performance, egg quality, blood parameters and egg yolk cholesterol in laying hens. Poult Sci J 2015; 3(2): 105-111.
28. Pignatelli P, Lenti L, Sanguigni V, et al. Carnitine inhibits arachidonic acid turnover, platelet function, and oxidative stress. Am J Physiol Heart Circ Physiol 2003; 284(1): H41-H48.
29. Suresh D, Srinivasan K. Studies on the in vitro absorption of spice principles - curcumin, capsaicin and piperine in rat intestines. Food Chem Toxicol 2007; 45(8): 1437-1442.
30. Madsen KL, Preisler N, Rasmussen J, et al. L-carnitine improves skeletal muscle fat oxidation in primary carnitine deficiency. J Clin Endocrinol Metab 2018; 103(12): 4580-4588.
31. Magoulas PL, El-Hattab AW. Systemic primary carnitine deficiency: an overview of clinical manifestations, diagnosis, and management. Orphanet J Rare Dis 2012; 7: 68. doi: 10.1186/1750-1172-7-68.
32. Agarwal A, Sengupta P, Durairajanayagam D. Role of L-carnitine in female infertility. Reprod Biol Endocrinol 2018; 16(1): 5. doi: 10.1186/s12958-018-0323-4.
33. Mirzaei M, Bouyeh M, Zahedi A, et al. Influence of dietary L‐carnitine and lysine-methionine levels on reproductive performance and blood metabolic constituents of breeder ducks. Reprod Domest Anim 2022; 57(3): 253-261.
34. Wu G. Important roles of dietary taurine, creatine, carnosine, anserine and 4-hydroxyproline in human nutrition and health. Amino acids 2020; 52(3): 329-360.
35. Ghods-Alavi B, Samie H, Jahanian R. Effects of supplementary dietary L-carnitine on performance and egg quality of laying hens fed diets different in fat level. Ital J Anim Sci 2010; 9(e3): 11-15.
36. Ringseis R, Keller J, Eder K. Basic mechanisms of the regulation of L‐carnitine status in monogastrics and efficacy of L‐carnitine as a feed additive in pigs and poultry. J Anim Physiol Anim Nutr (Berl) 2018; 102(6): 1686-1719.
37. Ahn DU, Sell JL, Jo C, et al. Effect of dietary conjugated linoleic acid on the quality characteristics of chicken eggs during refrigerated storage. Poult Sci 1999; 78(6): 922-928.
38. Irawan A, Ningsih N, Hafizuddin, et al. Supplementary n-3 fatty acids sources on performance and formation of omega-3 in egg of laying hens: a meta-analysis. Poult Sci 2022; 101(1): 101566. doi: 10.1016/j.psj. 2021.101566.
39. Fraeye I, Bruneel C, Lemahieu C, et al. Dietary enrichment of eggs with omega-3 fatty acids: a review. Food Res Int 2012; 48(2): 961-969.
40. Ehr IJ, Persia ME, Bobeck EA. Comparative omega-3 fatty acid enrichment of egg yolks from first-cycle laying hens fed flaxseed oil or ground flaxseed. Poult Sci 2017; 96(6): 1791-1799.
41. Aguillón-Páez YJ, Romero LA, Diaz GJ. Effect of full-fat sunflower or flaxseed seeds dietary inclusion on performance, egg yolk fatty acid profile and egg quality in laying hens. Anim Nutr 2020; 6(2): 179-184.
42. Lee SH, Kim YB, Kim DH, et al. Dietary soluble flaxseed oils as a source of omega-3 polyunsaturated fatty acids for laying hens. Poult Sci 2021; 100(8): 101276. doi: 10.1016/j.psj.2021.101276.
43. Rizzi L, Bochicchio D, Bargellini A, et al. Effects of dietary microalgae, other lipid sources, inorganic selenium and iodine on yolk n-3 fatty acid composition, selenium content and quality of eggs in laying hens. J Sci Food Agric 2009; 89(10): 1775-1781.
44. Ngo Njembe MT, Dormal E, Gardin C, et al. Effect of the dietary combination of flaxseed and Ricinodendron heudelotii or Punica granatum seed oil on the fatty acid profile of eggs. Food Chem 2021; 344: 128668. doi: 10.1016/j.foodchem.2020.128668.
45. Faitarone ABG, Garcia EA, Roça RO, et al. Yolk color and lipid oxidation of the eggs of commercial white layers fed diets supplemented with vegetable oils. Rev Bras Cienc Avic 2016; 18: 09-16.
46. Hargis PS, Van Elswyk ME, Hargis BM. Dietary modification of yolk lipid with menhaden oil. Poult Sci 1991; 70(4): 874-883.
47. Corduk M, Sarica S, Calikoglu E, et al. Effects of L-carnitine supplementation to diets with different fat sources and energy levels on fatty acid composition of egg yolk of laying hens. J Sci Food Agric 2008; 88(13): 2244-2252.
48. Mast J, Buyse J, Goddeeris BM. Dietary L-carnitine supplementation increases antigen-specific immunoglobulin G production in broiler chickens. Br J Nutr 2000; 83(2): 161-166.
49. Cherian G, Gonzalez D, Ryu KS, et al. Long-term feeding of conjugated linoleic acid and fish oil to laying hens: effects on hepatic histopathology, egg quality, and lipid components. J Appl Poult Res 2007; 16(3): 420-428.
50. Pappas AC, Acamovic T, Sparks NH, et al. Effects of supplementing broiler breeder diets with organic selenium and polyunsaturated fatty acids on egg quality during storage. Poult Sci 2005; 84(6): 865-874.
