Impact of Dietary Supplementation of Cysteamine on Egg Taurine Deposition, Egg Quality, Production Performance and Ovary Development in Laying Hens

SIMPLE SUMMARY: Taurine is a necessary amino acid for human health, while cysteamine is an intermediate metabolite to the synthesis of taurine. This study investigated effects of dietary cysteamine supplementation on the egg taurine deposition efficiency, egg quality, production performance and ovary development in laying hens. The results of this study indicate that cysteamine supplementation benefits yolk taurine deposition in both peak and late stages of egg production, but hens at the late stage of egg production showed depressed production performance and egg quality. The present study revealed that laying hens at the peak stage of egg production are suitable for cysteamine diets to produce high-taurine eggs. ABSTRACT: This study aimed to examine the effect of dietary cysteamine on yolk taurine content in hens during different egg production periods. In Exp. 1, China Agricultural University-3 (CAU-3) hens at the peak stage of egg production (aged 31 wks) were used to explore the effect of diets supplemented with 0.1% cysteamine on yolk taurine content, egg quality and production performance. In Exp.2, two breeds of hens (half Hy-Line Brown and half CAU-3 hens) at the late stage of egg production (68 wks) were used to investigate the influence of diets supplemented with 0, 0.02%, 0.04%, 0.08% or 0.10% cysteamine on yolk taurine content, egg quality, production performance and ovary development. In Exp.1, diets supplemented with 0.1% cysteamine significantly increased yolk taurine content (p < 0.05) without negative influence on production performance or egg quality. In Exp.2, the highest yolk taurine content was observed when cysteamine was supplemented at 0.08% (p < 0.001). However, supplemental cysteamine linearly or quadratically decreased production performance over the first few weeks of feeding, and the effects disappeared with continued feeding (p < 0.05). In conclusion, this study indicated that cysteamine supplementation benefits yolk taurine deposition in hens at both peak and late stage of egg production, but hens at the late stage of egg production show depressed production performance and egg quality.