Fish muscle: the exceptional case of notothenioids

Abstract

Fish skeletal muscle is an excellent model for studying muscle structure and function, since it has a very well-structured arrangement with different fiber types segregated in the axial and pectoral fin muscles. The morphological and physiological characteristics of the different muscle fiber types have been studied in several teleost species. In fish muscle, fiber number and size varies with the species considered, limiting fish maximum final length due to constraints in metabolites and oxygen diffusion. In this work, we analyze some special characteristics of the skeletal muscle of the suborder Notothenioidei. They experienced an impressive radiation inside Antarctic waters, a stable and cold environment that could account for some of their special characteristics. The number of muscle fibers is very low, 12,700-164,000, in comparison to 550,000-1,200,000 in Salmo salar of similar sizes. The size of the fibers is very large, reaching 600 microm in diameter, while for example Salmo salar of similar sizes have fibers of 220 microm maximum diameter. Evolutionary adjustment in cell cycle length for working at low temperature has been shown in Harpagifer antarcticus (111 h at 0 degrees C), when compared to the closely related sub-Antarctic species Harpagifer bispinis (150 h at 5 degrees C). Maximum muscle fiber number decreases towards the more derived notothenioids, a trend that is more related to phylogeny than to geographical distribution (and hence water temperature), with values as low as 3,600 in Harpagifer bispinis. Mitochondria volume density in slow muscles of notothenioids is very high (reaching 0.56) and since maximal rates of substrate oxidation by mitochondria is not enhanced, at least in demersal notothenioids, volume density is the only means of overcoming thermal constraints on oxidative capacity. In brief, some characteristics of the muscles of notothenioids have an apparent phylogenetic component while others seem to be adaptations to low temperature.

Antarctic Fish Metabolic Responses as Potential Biomarkers of Environmental Impact

“…On the other hand, in teleost fishes, the muscle represents a major part (more than 60%) of the body mass. The activity of this tissue is of vital importance in the escape from the predators and prey capture (Fernández & Calvo 2009). The aerobic energetic muscular routine in these Antarctic fishes had been associated to the presence of large quantity of lipids, high mitochondrial density, oxygen consumption and the presence of mitochondrial fat droplets (Lin et al 1974, Kamler et al 2001, Johnston 2003.…”

Length–weight relationship of six notothenioid species from sub‐Antarctic waters (Beagle Channel, Argentina)

“…The suborder notothenioidei is the dominant component of the ichthyophauna in the Beagle Channel (Lloris & Rucabado, ; López et al, 1996; Moreno & Jara, ; Vanella, Fernández, Romero, & Calvo, ). Although some studies focused on ecological and biological aspects of notothenioid species occurring in the Beagle Channel have been carried out (e.g., Cussac, Fernández, Gómez, & López, ; Fernández & Calvo, ; Fernández et al, ; Vanella, Boy, & Fernández, ), little is known regarding the growth parameters of these species in the wild.…”

Characterization and Expression Analysis of Myogenin Gene in White Muscle of Chinese Mandarin Fish, Siniperca chuatsi

“…Fish skeletal muscle is composed of two spatially separated fibers, white, fast-twitch muscle make up the bulk of fish body, whereas red, slow-twitch fibers are found in a narrow mid-lateral band immediately under skin [1] and it provides an excellent model for the study of muscle development and the mechanisms underlying muscle cellularity [2]. Similar to other vertebrates, fish skeletal muscle development involves a series of events in which cells in the paraxial mesoderm are firstly induced to form myoblasts and subsequently differentiate into myotubes, and the myotubes then mature into myofibers and grow by recruiting other myoblasts [3].…”