Responses of Chick Myoblast Proliferation to Branched‐Chain Amino Acids in a Three‐Component System.

This study investigated the combined effect of branched‐chain amino acids (BCAAs), valine (Val), leucine (Leu), and isoleucine (Ile) on chick myoblast proliferation and associated gene expression within a three‐component system. Isolated myoblasts were incubated in 22 different culture media, designed using a {3, 5} simplex lattice design to cover the entire range of compositions for each BCAA. The proliferation was estimated based on cell quantities after 72 h of incubation. The proliferation data under different BCAA combinations were fitted using Scheffé's seven‐term special cubic model for three components. The response surfaces of proliferation showed a convex configuration, with increases in Ile leading to a decrease in proliferation. The maximal proliferation was observed at Leu and Val proportions of 3:7 and 1:1 in an Ile‐free medium, as measured by the DNA assay and water‐soluble tetrazolium salt (WST‐8) assay, respectively. These findings suggest that Val has a greater influence than Leu on myoblast proliferation, particularly in DNA content. The responses of myoblast proliferation‐associated factors, Pax7 and p21, corresponded to the proliferation evaluated with DNA and WST‐8 assays, respectively. These results indicate that the growth of chick myoblast cells is affected by the combination of BCAAs in a three‐component system. [ABSTRACT FROM AUTHOR]