In recent years, zinc sources have experienced the development process from inorganic zinc to organic zinc, including amino acid-chelated zinc. Among them, many studies have shown that amino acid-chelated zinc has higher biological efficacy, utilization rate, and better stability, which could improve growth performance and reduce environmental pollution.

In order to investigate the physiological mechanisms of amino acid-chelated zinc in improving myoblast growth and increasing bioavailability, Guangzhou Tanke Bio-tech Co., Ltd. (hereinafter referred to as “Tanke”) cooperated with Chinese Academy of Sciences to conduct a study on mouse myoblast growth in vitro. Please refer to the online complete report at https://www.frontiersin.org/articles/10.3389/fnut.2022.857393/full


Figure 1: : CCK-8 (A) in cell proliferation and morphological responses in cell differentiation (B) of C2C12 cell line by adding different zinc sources.

In the in vitro trial, 25 or 75 mM zinc sulfate (ZnSO4), methionine-chelated zinc (ZnMet), and glycine-chelated zinc (ZnGly) were co-cultured with the myoblast during proliferation and differentiation. Above mentioned ZnMet and ZnGly were supplied by Tanke. The results showed that the amino acid-chelated zinc supplementation enhances cell proliferation and differentiation in mouse myoblast, and regulates the distribution in S and G2/M phases (P < 0.05). 

CCK8 results (Figure 1A) showed that amino acid-chelated zinc largely increased the viability of myoblasts, suggesting that amino acid-chelated zinc promotes C2C12 myoblast growth via the cell cycle pathway. After 8 days of induced differentiation, the myotubes were arranged in a bundle that can be clearly seen in four groups, especially in the ZnMet group. As shown in Figure 1B, the number of myotubes in the control group is significantly less than ZnSO4, ZnMet, and ZnGly groups. Meanwhile, the arrangement of the myotubes in the ZnMet and ZnGly groups is more regular than the ZnSO4 group. It can be seen that ZnMet and ZnGly can significantly promote differentiation and the formation of myotubes in C2C12 cells.

CHELATED ZINC ENHANCES Synthesis of Protein by activating mTOR signaling pathway

The mTOR signaling pathway is a central regulator of protein synthesis. As presented in Figure 2, phosphorylated protein expression levels of mTOR pathway (mTOR, 4EBP1, and P70S6K1) (A) and the ratios of p-mTOR to mTOR, p-4EBP1 to 4EBP1, and p-P70S6K1-P70S6K1 (B) are up-regulated in myotubes after treatment with 25µM ZnMet (P < 0.05). It indicated that ZnMet enhanced synthesis of protein, which is consistent with the result of our animal experiment. Amino-acid chelated zinc increased body weight and carcass weight.

In conclusion, amino acid-chelated zinc could improve myoblast growth and increases bioavailability, which appears to be associated with the cell cycle and mTOR pathways, ultimately enhancing muscle mass. These are convincing evidences of chelated Zn improves animal growth.

Tanke is a professional manufacturer of organic trace minerals from China. They have focused on the R&D, production and marketing of amino acid-chelate minerals since 1997, and certified with ISO9001, ISO22000 and FAMI-QS feed safety and quality management system. Tanke and Kartal Kimya, a leading premix manufacturers and feed additive supplier company in Turkiye since 1985, have been cooperating together for over 10 years to promote and popularize the application of organic trace minerals in animal feeding in Turkiye. Both companies agree that, organic trace minerals are making and will keep making great contribution to the sustainability of feed and food industry. For example, QILI®-Zn, a crystallized Zn-Gly produced by Tanke’s special technology, has enjoyed high reputation in the market due to the high bioavailability, high stability, and cost effectiveness.