Effects of Thermal Challenge on Turkey Muscle Development and Meat Quality

Exposure of newly hatched turkey poults to hot or cold thermal stress often results in detrimental effects on breast muscle growth and development.  Typical changes include increased lipid deposition and damage to muscle ultrastructure, leading to inferior meat quality with consequent economic losses to producers and processors. A leading candidate for mediating the effects of thermal challenge on muscle growth and development is the satellite cell which is the progenitor of post-hatch muscle growth. We hypothesized that hot or cold thermal challenge alters gene expression, resulting in changes in muscle structure that ultimately produce inferior meat quality characteristics in the market-age bird. This study examined effects of temperature on proliferation and differentiation of cultured turkey p. major satellite cells from the RBC2 (control) line and growth-selected F line. While cells from both lines show temperature-dependent changes in function, the F line cells are more sensitive than RBC2 satellite cells. In a subsequent study, newly hatched RBC2 and F line turkey poults were exposed to different brooding temperatures (31, 35, or 39C) for 3 days followed growth to 16 weeks under standard conditions. Analysis of p. major ultrastructure indicates larger muscle fiber width and reduced number of cells per unit area in F line birds at the elevated brooding temperatures. Understanding the mechanism of satellite cell response to thermal challenge will be useful in development of adaptation strategies to improve thermo-tolerance of the birds as well as meat quality characteristics.