Figure 3. Muscle fiber cross-sections in the pectoralis major muscle between the low weight (LW) and random bred control (RBC) quail lines at 42 (A) and 75 (B) d post-hatch that were stained for myosin ATPase activity after acidic preincubation (pH 4.6).

Bar indicates 100 µm. Abbreviations: IIA, fiber type IIA (fast-twitch and oxido-glycolytic); IIB, fiber type IIB (fast-twitch and glycolytic).