Investigation of the Effect of Heat Stress on Egg Quality in Laying Hens

Öz

The thermoregulatory capacity of poultry kept in high-temperature environments is significantly impaired; heat stress can negatively affect their productive performance and health, leading to death. This study was aimed to determine the effect of high temperature on egg quality traits and the applicability of Brix refractometry in measuring total serum protein in eggs. A total of 24 Lohman Brown laying hens (12 control/12 heat stress) aged 30 weeks were used in the study. Laying hens were housed individually in an area of 1350 cm2. The experiment began one week after the laying hens were placed in the cages and lasted a total of four weeks. The room temperature in the control group was maintained at 24±2 °C (24 hours); the room temperature in the heat stress group was kept at 35±2 °C (09:00-17:00). The results showed that egg weight (g) decreased in the heat stress group (p=0.001). Additionally, it was determined that eggshell thickness (mm) significantly decreased in the stress-applied group (p=0.002). Similarly, egg yolk height (mm) was found to be significantly lower in the heat stress group (p=0.002); in contrast, the incidence of blood and meat spots in the eggs was found to be higher (p=0.01). These findings suggest that heat stress negatively affects various internal and external egg quality parameters. Moreover while the Brix refractometer appeared to offer a practical quick approach for estimating egg serum total protein it revealed no statistically significant differences. Therefore, while its use appears promising, further studies are needed to confirm its reliability under different physiological conditions.

Anahtar Kelimeler

• Brix refractometer
• Egg quality parameters
• Heat stress
• Laying hen
• Total protein.

Yumurtacı Tavuklarda Sıcaklık Stresinin Yumurta Kalitesi Üzerine Etkisinin Araştırılması

Öz

Yüksek sıcaklık ortamlarında tutulan kümes hayvanlarının ısı düzenleme kapasitesi önemli ölçüde bozulur; sıcaklık stresi, üretim performanslarını ve sağlıklarını olumsuz etkileyerek ölüme yol açabilir. Bu çalışmada, yüksek sıcaklığın yumurta kalite özellikleri üzerine etkisi ve Brix refraktometrisinin yumurtalarda toplam serum proteininin ölçümünde uygulanabilirliği araştırılmıştır. Çalışmada, 30 haftalık toplam 24 Lohman Brown yumurtacı tavuk (12 kontrol/12 sıcaklık stresi) kullanılmıştır. Tavuklar, 1350 cm2'lik bir alanda bireysel barındırılmıştır. Deney, yumurtacı tavukların kafeslere yerleştirilmesinden bir hafta sonra başlamış ve toplam dört hafta sürmüştür. Kontrol grubunda oda sıcaklığı 24±2 °C (24 saat) olarak tutulurken, sıcaklık stresi grubunda oda sıcaklığı 35±2 °C (09:00-17:00) olarak tutulmuştur. Sonuçlar, sıcaklık stresi grubunda yumurta ağırlığının (g) azaldığını göstermiştir (p=0.001). Ayrıca, stres uygulanan grupta yumurta kabuğu kalınlığının (mm) anlamlı düzeyde azaldığı belirlenmiştir (p=0.002). Benzer şekilde, yumurta sarısı yüksekliği (mm) sıcaklık stresi grubunda anlamlı olarak daha düşük bulunmuş (p=0.002), buna karşın yumurtalarda kan ve et lekesi görülme sıklığının ise daha yüksek olduğu tespit edilmiştir (p=0.01). Bu bulgular, sıcaklık stresinin çeşitli yumurta iç ve dış kalite parametrelerini olumsuz etkilediğini göstermektedir. Ek olarak, Brix refraktometresinin serum toplam protein düzeylerinin hızlı değerlendirilmesi için potansiyel bir araç olabileceği belirlenmiştir. Bu sonuçlar, hem sıcaklık stresinin yumurta kalite özellikleri üzerindeki etkisi hem de toplam protein ölçümü için alternatif yöntemlerin geliştirilmesi açısından literatüre katkıda bulunmaktadır.

Anahtar Kelimeler

• Brix refraktometresi
• Sıcaklık stresi
• Total protein
• Yumurtacı tavuk
• Yumurta kalite parametreleri.

Kaynakça

1. Abbas G (2021). Combating heat stress in laying hens a review. Pak J Sci, 73 (4), 633-655.
2. Ajakaiye J, Perez-Bello A, Mollineda-Trujillo A (2011). Impact of heat stress on egg quality in layer hens supplemented with l-ascorbic acid and dl-tocopherol acetate. Vet Arh, 81 (1), 119-132.
3. Afacan RSU (2023). Analyses of chemical and physical egg quality parameters of laying hens housed in different conditions in Turkey. SAUJS, 27 (3), 614-620.
4. Barrett NW, Rowland K, Schmidt CJ, et al. (2019). Effects of acute and chronic heat stress on the performance, egg quality, body temperature, and blood gas parameters of laying hens. Poult Sci, 98 (12), 6684-6692.
5. Boateng M, Atuahene PY, Amoah KO, Frimpong YO, Okai DB (2022). Incidence of blood and meat spots in eggs from a commercial poultry farm. GJS, 63 (1), 90-96.
6. Contreras S, Demosthene B, Kang E, Huo Q (2024). Using brix refractometry to measure the total protein level in chicken egg whites: Preliminary data. Measurement: Food, 15, 100173.
7. Chung MK, Choi JH, Chung YK, Chee KM (2005). Effects of dietary vitamins C and E on egg shell quality of broiler breeder hens exposed to heat stress. AJAS, 18 (4), 545-551.
8. Chen Y, Yu S, Zhang L, Xiao M, An L (2023). Effects and mechanisms investigation of heat stress on egg yolk quality in huaixiang chickens. Animals, 13 (22), 3513.

9. Durmus I, Kamanli S (2015). Effects of cold and heat stress on egg quality traits of a newly developed native hybrid layer. TURJAF, 3 (6), 44-447.
10. El-Tarabany MS (2016). Effect of thermal stress on fertility and egg quality of Japanese quail. J Therm Biol, 61, 38-43.
11. Fouad AM, Chen W, Ruan D, et al. (2016). Impact of heat stress on meat, egg quality, immunity and fertility in poultry and nutritional factors that overcome these effects: A review. Int J Poult Sci,15 (3), 81.
12. Franco-Jimenez DJ, Scheideler SE, Kittok RJ, et al. (2007). Differential effects of heat stress in three strains of laying hens. J Appl Poult Res, 16 (4), 628-634.
13. Hammouche D, Mouss AK, Meziane R (2025). Impact of climate change on thermoregulation, blood attributes and production performance in laying hens. JLST, 13 (1), 39-46.
14. Hassan S, Habashy W, Ghoname M, Elnaggar A (2023). Blood hematology and biochemical of four laying hen strains exposed to acute heat stress. Int J Biometeorol, 67 (4), 675-686.
15. Kessler EC, Bruckmaier RM, Gross JJ (2021). Comparative estimation of colostrum quality by Brix refractometry in bovine, caprine, and ovine colostrum. JDS, 104 (2), 2438-2444.
16. Kilic I, Simsek E (2013). The effects of heat stress on egg production and quality of laying hens. J Anim Vet Adv, 12 (1), 42-7.
17. Kim DH, Lee KW (2023). An update on heat stress in laying hens. J World's Poult Sci, 79 (4), 689-712.
18. Kim HR, Ryu C, Lee SD, Cho JH, Kang H (2024). Effects of heat stress on the laying performance, egg quality, and physiological response of laying hens. Animals, 14 (7), 1076.
19. Kirunda DF, Scheideler SE, McKee SR (2001). The efficacy of vitamin E (DL-alpha-tocopheryl acetate) supplementation in hen diets to alleviate egg quality deterioration associated with high temperature exposure. Poult Sci, 80, 1378-1383.
20. Lara LJ, Rostagno MH (2013). Impact of heat stress on poultry production. Animals, 3 (2), 356-369.
21. Liu M, Lu Y, Gao P, et al. (2020). Effect of curcumin on laying performance, egg quality, endocrine hormones, and immune activity in heat-stressed hens. Poult Sci, 99 (4), 2196-2202.
22. Mashaly MM, Hendricks GL, Kalama MA, et al. (2004). Effect of heat stress on production parameters and immune responses of commercial laying hens. Poult Sci. 83, 889–894.
23. Mignon-Grasteau S, Moreri U, Narcy A, et al. (2015). Robustness to chronic heat stress in laying hens: a meta-analysis. Poult Sci, 94 (4), 586-600.
24. Oluwagbenga EM, Tetel V, Schober J, Fraley GS (2022). Chronic heat stress part 1: Decrease in egg quality, increase in cortisol levels in egg albumen, and reduction in fertility of breeder pekin ducks. Front Physiol, 13, 1019741.
25. Onbaşılar EE (2005). Kanatlılarda Stres (Review). Hayvancılık Araştırma Dergisi, 15 (2), 30–35.
26. Sahin N, Hayirli A, Orhan CE. et al. (2018). Effects of the supplemental chromium form on performance and metabolic profile in laying hens exposed to heat stress. Poult Sci, 97 (4), 1298-1305.
27. Uysal A, Laçin E (2024). The effect of different cage densities on laying performance and egg quality in brown and white laying hens. Rev Bras, 26, eRBCA-2024.
28. Yavuz HK, Özcan MM, Lemiasheuski V (2018). The effect of some chemical additives on the foaming performance of the pasteurized liquid egg white. Austin J Nutr Metab, 5 (1).