Dietary Dunaliella salina microalgae enriches eggs with carotenoids and long-chain omega-3 fatty acids, enhancing the antioxidant and immune responses in heat-stressed laying hens

Mahmoud Madkour ^1* Sami I Ali ² Mahmoud Alagawany ³ Mohamed S El-Kholy ³ Farouk K El-Baz ² Abdulmohsen Hussen Alqhtani ⁴ Abdulrahman S Alharthi ⁴ Anthony Pokoo-Aikins ⁵ Ahmed A Elolimy ^1,6

• ¹ Department of Animal Production, National Research Centre (Egypt), Giza, Egypt
• ² Department of Plant Biochemistry, National Research Centre (Egypt), Cairo, Beni Suef, Egypt
• ³ Department of Poultry, Faculty of Agriculture, Zagazig University, Zagazig, Al Sharqia, Egypt
• ⁴ Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
• ⁵ Toxicology and Mycotoxin Research Unit, U.S. National Poultry Research Center, Agricultural Research Service (USDA), Athens, Georgia, United States
• ⁶ College of Agriculture and Veterinary Medicine, United Arab Emirates University, AlAin, Abu Dhabi, United Arab Emirates

Dunaliella salina (DS) is a prospective source of bioactive carotenoids, including beta-carotene, zeaxanthin, and omega-3 fatty acids. The effect of dietary supplementation of DS on the productive performance, immune response, and egg quality of heat-stressed laying hens has not been comprehensively studied. We investigated how dietary D. salina supplementation affects the deposition of bioactive carotenoids and omega-3 fatty acids in egg yolks of laying hens experiencing summer heat stress, as determined by the Temperature-Humidity Index (THI). The influence of D. salina supplementation on the productive performance, immune response, and antioxidant status of heat-stressed laying hens was assessed. The hens were fed four dosages of DS (0 (control), 0.5, 1, and 1.5 g/kg diet) for 60 days, and eggs were collected at three intervals: 15, 30, and 60 days after the start of the experiment. Including DS at 1 g/kg improved egg production and feed conversion, with improved antioxidant status via a marked inhibitory effect on malondialdehyde in heat-stressed laying hens. (IT), low atherogenicity index (IA), and high hypocholesterolemic/hypercholesterolemic index (h/H). Feeding heat-stressed laying hens DS improved their productivity and antioxidant status, resulting in functional eggs enriched with bioactive carotenoids (astaxanthin, zeaxanthin, and lutein) and beneficial omega-3 fatty acids.