As the two primary limiting essential amino acids for ruminants, methionine and lysine greatly affect growth performance and nutrient metabolism. Dietary amino acid imbalance and deficiency are common problems in ruminant breeding production, easily causing growth retardation, intestinal metabolic disorder and reduced feeding efficiency.

Researchers led by Prof. TAN Zhiliang from the Institute of Subtropical Agriculture, Chinese Academy of Sciences, revealed the different regulatory patterns of dietary methionine and lysine deficiency on tissue autophagy and metabolic pathways in goats.

The latest study published in BMC Veterinary Research on June 12.

The results showed that single dietary lysine deficiency reduced autophagy in the goat jejunal mucosa. In response, the body upregulated the expression of the ATF4 gene to maintain amino acid metabolic homeostasis in the rumen, jejunum, and ileum. By contrast, methionine deficiency did not exert significant regulatory effects on autophagy in goat tissues, and instead mainly interfered with intestinal metabolic pathways.

Furthermore, metabolomic analysis revealed that the contents of sorbitol and N-acetylglucosamine in the jejunal mucosa were significantly elevated specifically in the methionine-deficient group. On the other hand, lysine deficiency induced significant accumulation of nine metabolites, including homocystine, dimethyluric acid, and Leu-Ala. These findings further confirm that methionine deficiency and lysine deficiency regulate the physiological functions of goats through completely distinct molecular pathways.

This study advances our understanding of amino acid-sensing mechanisms and tissue adaptive homeostasis in ruminants, and provide new theoretical support for the precise nutritional feeding of goats.

Contact: KANG Jinhe

E-mail: kangjh@isa.ac.cn

Figure 1Dietary methionine and lysine deficiency differentially affect autophagy and metabolism in goats（Imaged by KANG Jinhe）