Overcoming nature’s paradox in skeletal muscle to optimise animal production

Abstract

Nature’s paradox in skeletal muscle describes the seemingly mutually exclusive relationship between muscle fibre size and oxidative capacity. In mammals, there is a constraint on the size at which mitochondria-rich, high O2-dependent oxidative fibres can attain before they become anoxic or adapt to a glycolytic phenotype, being less reliant on O2. This implies that a muscle fibre can hypertrophy at the expense of its endurance capacity. Adaptations to activity (exercise) generally obey this relationship, with optimal muscle endurance generally being linked to an enhanced proportion of small, slow oxidative fibres and muscle strength (force and/or power) being linked to an enhanced proportion of large, fast glycolytic fibres. This relationship generally constrains not only the physiological limits of performance (e.g. speed and endurance), but also the capacity to manipulate muscle attributes such as fibre size and composition, with important relevance to the livestock and aquaculture industries for producing specific muscle traits such as (flesh) quality, texture and taste. Highly glycolytic (white) muscles have different traits than do highly oxidative (red) muscles and so the ability to manipulate muscle attributes to produce flesh with specific traits has important implications for optimising meat production and quality. Understanding the biological regulation of muscle size, and phenotype and the capacity to manipulate signalling pathways to produce specific attributes, has important implications for promoting ethically sustainable and profitable commercial livestock and aquaculture practices and for developing alternative food sources, including ‘laboratory meat’ or ‘clean meat’. This review describes the exciting potential of manipulating muscle attributes relevant to animal production, through traditional nutritional and pharmacological approaches and through viral-mediated strategies that could theoretically push the limits of muscle fibre growth, adaptation and plasticity.

Beta-agonist drugs modulate the proliferation and differentiation of skeletal muscle cells in vitro

“…Due to their so-called “repartitioning effects” [ 3 ], oral administration of β-agonist drugs to animals had enhanced their growth and altered their body composition [ 4 , 7 ]. The anabolic effects of β-agonists had been confirmed by several in vivo and in vitro studies [ 3 , 8 , 9 ]. Moreover, certain β-agonists have also been engaged in muscle repair and restoration of muscle function after injury [ 3 ] as well as in myopathies [ 8 ].…”

“…The anabolic effects of β-agonists had been confirmed by several in vivo and in vitro studies [ 3 , 8 , 9 ]. Moreover, certain β-agonists have also been engaged in muscle repair and restoration of muscle function after injury [ 3 ] as well as in myopathies [ 8 ].…”

Recent Advances in Animal Nutrition – Australia: people and circumstances shaping this symposium’s successful first 50 years

“…Professor Gordon Lynch (University of Melbourne, Vic., Australia) presented the McClymont lecture and applied nature's paradox to skeletal muscle (that fibre size and oxidative capacity are mutually exclusive); he argued that, by better understanding the nature of the regulation of muscle size and phenotype, and by selectively manipulating biological signalling, scientists might unlock the paradox and produce both larger and more oxidative muscles (Lynch and Koopman 2019).…”

Desempenho, características de carcaça e qualidade de carne de bovinos Nelore e Rubia Gallega X Nelore confinados

“…Além disso, a idade também é um fator que pode afetar a frequência dos tipos de fibras musculares (HAWKINS; MOODY;KEMP, 1985). À medida que ocorre o avanço da idade pode haver modulação de fibras musculares, fibras SO podem ser moduladas à FG(LYNCH & KOOPMAN, 2019). De acordo com eRehfeldt et al (2004), bovinos DM possuem maior número de fibras musculares, com maior proporção de fibras glicolíticas pois estas fibras apresentam maior diâmetro que fibras musculares oxidativas.…”