Effects of dietary taurine supplementation on polyunsaturated fatty acids, cholesterol and egg quality of egg of hens

Wang Shunyang¹Zhang Qi Qi¹Lu Hui Min¹Yu Meng¹Mahmoud M Alagawany²Chen Cheng^3*Zhongxin Zhou^1*

• ¹Huazhong Agricultural University, Wuhan, China
• ²Zagazig University Faculty of Agriculture, Zagazig, Egypt
• ³Shihezi University, Shihezi, China

Abstract 25 Objective: This study aimed to assess the impact of dietary taurine supplementation on egg 26 quality, polyunsaturated fatty acids, and cholesterol contents in egg during the late laying period 27 in hens. 28 Methods: A total of 102 44-week-old Roman pink laying hens were randomly divided into six 29 groups, one control group and five treatment groups additionally supplied with 0.01%, 0.02%, 30 0.05%, 0.1%, and 0.2% Taurine (weight/weight). Feed intake and body weight were recorded to 31 calculate production performance, and eggs were collected to analyze egg quality. At the end of 32 the study, 10 laying hens were randomly selected from each group and slaughtered to collect 33 blood, liver, and other samples. 34 Results: The results revealed that 0.05% or 0.1% taurine significantly increased the contents of 35 C18-3n and C18-2n polyunsaturated fatty acids in yolks (P < 0.05). Dietary 0.1% or 0.2% taurine 36 significantly decreased the total cholesterol content (P < 0.05) in egg yolks. Moreover, 0.05%, 37 0.1% and 0.2% taurine significantly reduced the mRNA expression of the cholesterol synthesis 38 rate-limiting enzyme HMGCR and transcription factor SREBP2 in the livers of aged laying hens 39 (P < 0.05), and promoted hepatic cholesterol transporter protein ABCG5 and cholesterol esterase 40 ACAT2 mRNA expression (P < 0.05); 0.2% taurine promoted hepatic bile acid synthesis rate-41 limiting enzyme CYP7A1 mRNA expression (P < 0.05). Additionally, supplementation with 0.01% 42 to 0.2% taurine significantly increased egg weight, with 0.2% taurine significantly increased egg 43 Albumen height at week 4, with 0.05% and 0.1% taurine significantly increased egg Haugh units 44 at week 12, and with 0.02% to 0.2% taurine decreased yolk color at week 16 (P < 0.05). 45 Conclusion: Supplying 0.05% to 0.2% taurine improved specific aspects of egg quality, enhanced 46 contents of polyunsaturated fatty acids, and reduced egg yolk cholesterol during the late laying 47 period. This study provides scientific evidence for the further taurine use in egg production.