How Methionine and Lysine Affect Ruminants as Feed Additives?
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Due to the microbial actions in rumen, ruminants, including cattle, goats, sheep, giraffes, yaks, deer, antelope, and so on, can transform the non-quality protein into quality protein like urea, and acquire adequate amino acids for growth. This changes the amino acids profile in diets and affects the optimal amino acid absorption.

Given the significance and complex of amino acid metabolism, extensive efforts have been taken to explore the amino acids (AAs) sensing and transporting in monogastric animal but rarely in ruminants.

Researchers also have paid much attention on the essential AAs and the order of limiting AAs and hope to make optimum feed formula not only having balanced amino acids but also meeting the requirement of animals, which can benefit the production performance as well as the health welfare of ruminants to a great extent.

Besides, Met and Lys are most essential components relative to other amino acids. Researchers have conducted a range of experiments to investigate the order of limiting AAs. It has been found by the group led by professor TAN Zhiliang, form the Institute of Subtropical Agriculture (ISA) of Chinese Academy of Sciences, that the first and second limiting AAs of growing goats on a basis of maize stover diet are Met, Lys.

Recently, an experiment conducted by Zhu Xiaoli, a doctoral student in ISA had illustrated the effects of dietary methionine and lysine supplementation on nutrients digestion, and serum parameters in growing Liuyang black goats -a local breed of goat in Changsha.

Dr. ZHU used twenty weather growing goats and assigned randomly to 4 kinds of diets, which had different levels of methionine and lysine. MRNA expressions of related amino acid sensing and transporting genes are also analyzed in this research.

Scientists found that although the treatments didn’t affect the nutrients digestion, the dietary methionine and lysine supplementation changed serum amino acids profiles.

Furthermore, the mRNA expression of some amino acid transporters in certain part of intestine was different.

In addition of the mRNA expression change of mTOR pathway, protein synthesis tended to be influenced. Amino acids are vital nutrient substance.
The findings provided valuable information for improving animal production through amino acid nutrition regulation.

This study was supported by the grants from the National Natural Science Foundation of China (Grant No. 31320103917, 31372342), CAS Visiting Professorship for Senior & Young International Scientists (Grant No. 2013Y2GA0010, 2017VBA0026), and Hunan Provincial Creation Development Project (Grant No. 2013TF3006).

The present research entitled “Effects of dietary methionine and lysine supplementation on nutrients digestion, serum parameters and mRNA expression of related amino acid sensing and transporting genes in growing goats” has been published online by Small Ruminant Research. Details could be found at

Contact: TAN Zhiliang


Institute of Subtropical Agriculture, Chinese Academy of Sciences