Fibre types in chicken skeletal muscles and their changes in muscular dystrophy

Abstract

SUMMARY1. Five major fibre types in chicken skeletal muscles are recognized, based upon their histochemical and morphological characteristics. A classification of these which is readily related to a commonly used classification of mammalian muscle fibre types is given.2. Seven muscles of the chicken were analysed in recognizing this range of fibre types. The proportions of the different types in each of these were determined. In some cases a gradient of fibre type composition exists across a single muscle.3. Measurements of muscle contraction were used in defining tonic muscles, which contain two fibre types. It was shown that in addition to the anterior latissimus dorsi (a.l.d.), previously well known to be a tonic muscle, two other muscles, the plantaris and the adductor profundus, are of the same class, but differ subtly from the ald. in certain features. Gross red colouration is not a useful diagnostic feature of slow muscles, since the tonic adductor profundus, for example, is white.4. Fibres similar histochemically to mammalian type I (slow-twitch) occur in some of the avian twitch muscles investigated. These are oxidative in character, and despite the fact that they are multiply innervated we suggest that these are avian slow-twitch fibres.5. The patterns of cholinesterases found in a skeletal muscle correspond to its fibre type composition, with regard to both the concentrations and the proportions of the multiple forms of enzyme present. The distinctive patterns of those forms of acetylcholinesterase in the different fibre types are described.6. The fibre type composition is changed by inherited muscular dystrophy in a characteristic manner. This change has so far been found (at the earlier stages of the disease) only in the muscles with a predominance of type II1B fibres in the normal chicken. Pathological changes within the fibres occur selectively in the type JIB fibres, but there are exceptions to this and the effect can be greatly modified by the type of neighbouring fibres.

Fast myosin light chain expression in chicken muscles studied by in situ hybridization.

“…Alkali pre-incubation was at pH 10.3 and 10.4. The fibers were typed according to Barnard et al (1982). …”

“…In the anterior region of this principally "slow tonic" muscle (Barnard et al, 1982), a mixture of fast and slow fibers has been found (Zhang et al 1985;Crow et al, 1983). In contrast to Zhang et al (1985), we found a majority of the slow fibers in the muscle's most anterior part to be of Type I instead of Type 111, based on the nomenclature of Barnard et al (1982), because after acid preincubation their myofibrillar ATPase reaction was stronger than that of Type 111 fibers (Figure 4e) and after alkali pre-treatment it was extinguished (not shown). Type I1 fibers in MA were of IIA subtype, based on their strong NADH tetrazolium reductase stain (Barnard et al, 1982) (Figure 4f).…”

Effect of Dietary β-1,4-Mannobiose on the Growth of Growing Broiler Chicks

“…One possible explanation is that the effect of dietary MNB on the skeletal muscle weight was different between muscle fiber types in the chicks. There is evidence that more than 99% of muscle fiber in the breast muscle is type II B fiber (Barnard et al, 1982). On the other hand, thigh muscles consist of several types of muscle fiber including type I, II A, II B, III A, and III B.…”

Distribution of the slow/cardiac isoform of skeletal muscle Ca(2+)-ATPase in developing and mature tissues of chickens determined using a monoclonal antibody.

“…Vertebrate skeletal muscle is composed of a heterogeneous population of exuafusal fibers, each of which is characterized by unique morphological, physiological, and biochemical properties (2,3,9,16,17). The current model for the way this diversity of fiber type is produced during development in avian muscle proposes that differentiation is initially under myogenic control, with different fiber types being derived from distinct myoblast cell lineages, but that continued differentiation in the late embryonic and post-hatch period becomes dependent on a variety of factors external to the muscle cell, such as innervation, hormones, and interactions with the extracellular matrix (25,29,34).…”