The study, published in Animal which was conducted in China and supported by the funding of the Southwest Minzu University, examined the impact of dietary Cysteamine on yolk taurine content in hens during different egg production periods.
Taurine, a free amino acid that widely exists in animals, is necessary for normal human body functioning and deficits are associated with multiple diseases such as myocardiopathy, renal dysfunction, dysplasia and retinal neuron injury. Cysteamine is an intermediate metabolite to the synthesis of taurine.
The Chinese researchers said that even though it had been shown previously that diets of chickens supplemented with taurine can improve the levels in egg yolks the costs of this are “significant.”
The result is that other methods have been used to improve taurine deposition such as using feather meal, but this is susceptible to salmonella contamination.
Two experiments were conducted in this study to analyse the impact of using Cysteamine.
In one experiment 180 laying hens at the peak stage of production at 31 weeks were assigned to two diet treatments over a five-week period. One with a basal diet and the second with a basal diet with 0.1% Cysteamine supplementation.
A second experiment was also conducted with 360 hens, aged 68 weeks, who were at the end of their egg production. Five dietary treatments of basal and different levels of Cysteamine were given over an eight-week period.
The results found that the diet supplemented with 0.1% Cysteamine “significantly improved” the yolk taurine level by 48.68% in the laying hens at the peak stage of egg production. It also revealed that it improved egg yolk colour without impacting on egg quality or production performance.
Hens at the later stage of egg production showed the highest yolk taurine content at a Cysteamine supplementation at 0.08%. But the late-stage hens showed a depressed production performance within the first six weeks and egg quality, except yolk colour, declined throughout the experiment.
The research concluded: “The present study revealed that laying hens at the peak stage of egg production are suitable for Cysteamine diets to produce high-taurine eggs.”
Meanwhile, Taurine has been recognised as a supplement in its own right with higher levels being shown to boost fish growth and feed efficiency in seabass.
"Impact of Dietary Supplementation of Cysteamine on Egg Taurine Deposition, Egg Quality, Production Performance and Ovary Development in Laying Hens"
Authors: Chen J, Wang Y, Tang Z, Guo X, Yuan J
Published: Animals, 2023