Flight muscle architecture and fiber type composition in quail and pigeon: A morphological anatomical and immunohistochemical study

Abstract

This study comparatively evaluated the anatomical, histological, and immunohistochemical characteristics of the major flight muscles, m. pectoralis, m. supracoracoideus, and m. latissimus dorsi, in quails (Coturnix coturnix) and pigeons (Columba livia). Samples were obtained from six adult individuals of each species. Following dissection, the origins, insertions, and topographical features of the muscles were documented. For histological assessment, formalin-fixed, paraffin-embedded tissues were processed and stained with Crossman's trichrome. Histometric analyses included muscle fiber count and diameter. In addition, the distributions of slow oxidative (SO), fast oxidative-glycolytic (FOG), and fast glycolytic (FG) fibers were determined immunohistochemically using the indirect streptavidin-biotin method. Macroscopic examination revealed species-related differences in the topographical organization of the examined flight muscles, with the m. pectoralis and m. supracoracoideus appearing more prominent in pigeons. Histometric analysis revealed higher muscle fiber counts in pigeons, whereas muscle fiber diameters were significantly greater in quails (p < 0.05). In the m. pectoralis, FOG fibers predominated in pigeons, which had a significantly lower proportion of FG fibers than quails (p < 0.001). FOG fibers were predominant in the m. supracoracoideus of both species, with no significant interspecies difference in fiber type distribution (p > 0.05). In the m. latissimus dorsi, pigeons had a significantly higher proportion of SO fibers than quails (p < 0.05). These anatomical and histological differences in flight muscle architecture and fiber type composition appear to reflect the distinct flight strategies of quails and pigeons and provide further insight into the functional morphology of avian flight.