Growth and development of sheep

Fourie, P. D.

doi:10.1080/00288233.1962.10419991

Cited by 12 publications

(3 citation statements)

References 6 publications

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“…These two muscles are both weight baring and generate mechanical power by fibre shortening for flexion and rotation of the lower limb. 31,32 However, they differ in innervation, blood supply and fibre-type composition. 32,33 34 ) for respiratory measurements.…”

Section: Methodsmentioning

confidence: 99%

Developmental programming of mitochondrial substrate metabolism in skeletal muscle of adult sheep by cortisol exposure before birth

Davies

Camm

Smith

et al. 2022

J Dev Orig Health Dis

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Prenatal glucocorticoid overexposure causes adult metabolic dysfunction in several species but its effects on adult mitochondrial function remain largely unknown. Using respirometry, this study examined mitochondrial substrate metabolism of fetal and adult ovine biceps femoris (BF) and semitendinosus (ST) muscles after cortisol infusion before birth. Physiological increases in fetal cortisol concentrations pre-term induced muscle- and substrate-specific changes in mitochondrial oxidative phosphorylation capacity in adulthood. These changes were accompanied by muscle-specific alterations in protein content, fibre composition and abundance of the mitochondrial electron transfer system (ETS) complexes. In adult ST, respiration using palmitoyl-carnitine and malate was increased after fetal cortisol treatment but not with other substrate combinations. There were also significant increases in protein content and reductions in the abundance of all four ETS complexes, but not ATP synthase, in the ST of adults receiving cortisol prenatally. In adult BF, intrauterine cortisol treatment had no effect on protein content, respiratory rates, ETS complex abundances or ATP synthase. Activity of citrate synthase, a marker of mitochondrial content, was unaffected by intrauterine treatment in both adult muscles. In the ST but not BF, respiratory rates using all substrate combinations were significantly lower in the adults than fetuses, predominantly in the saline-infused controls. The ontogenic and cortisol-induced changes in mitochondrial function were, therefore, more pronounced in the ST than BF muscle. Collectively, the results show that fetal cortisol overexposure programmes mitochondrial substrate metabolism in specific adult muscles with potential consequences for adult metabolism and energetics.

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Section: Methodsmentioning

confidence: 99%

Developmental programming of mitochondrial substrate metabolism in skeletal muscle of adult sheep by cortisol exposure before birth

Davies

Camm

Smith

et al. 2022

J Dev Orig Health Dis

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“…Two hindlimb skeletal muscles with different postnatal functions in locomotion, the biceps femoris (BF) and superficial digital flexor (SDF), were immediately collected and weighed. The BF is a large powerful, multifunctional muscle producing mechanical power by shortening while the SDF is a small flexor muscle generating force predominately by isometric contraction ( Fourie 1962 , Biewener 1998 ). The BF controls locomotive gait through extension and abduction of the hindlimb whereas the SDF controls foot placement important for allowing the neonate to stand ( Fourie 1962 , Walker & Luff 1995 ).…”

Section: Methodsmentioning

confidence: 99%

“…The BF is a large powerful, multifunctional muscle producing mechanical power by shortening while the SDF is a small flexor muscle generating force predominately by isometric contraction ( Fourie 1962 , Biewener 1998 ). The BF controls locomotive gait through extension and abduction of the hindlimb whereas the SDF controls foot placement important for allowing the neonate to stand ( Fourie 1962 , Walker & Luff 1995 ). Both muscles are of mixed fibre type with a combination of slow-twitch type I and fast-twitch type II fibres ( Davies 2018 ).…”

Section: Methodsmentioning

confidence: 99%

Glucocorticoid maturation of mitochondrial respiratory capacity in skeletal muscle before birth

Davies

Camm

Smith

et al. 2021

Journal of Endocrinology

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In adults, glucocorticoids act to match the supply and demand for energy during physiological challenges, partly through actions on tissue mitochondrial oxidative phosphorylation (OXPHOS) capacity. However, little is known about the role of the natural prepartum rise in fetal glucocorticoid concentrations in preparing tissues for the increased postnatal energy demands. This study examined the effect of manipulating cortisol concentrations in fetal sheep during late gestation on mitochondrial OXPHOS capacity of two skeletal muscles with different postnatal locomotive functions. Mitochondrial content, biogenesis markers, respiratory rates and expression of proteins and genes involved in the electron transfer system (ETS) and OXPHOS efficiency were measured in the biceps femoris (BF) and superficial digital flexor (SDF) of fetuses either infused with cortisol before the prepartum rise or adrenalectomised to prevent this increment. Cortisol infusion increased mitochondrial content, biogenesis markers, substrate-specific respiration rates and abundance of ETS Complex I and adenine nucleotide translocator (ANT1) in a muscle-specific manner that was more pronounced in the SDF than BF. Adrenalectomy reduced mitochondrial content and expression of PGC1α and ANT1 in both muscles, and ETS Complex IV abundance in the SDF near term. Uncoupling protein gene expression was unaffected by cortisol manipulations in both muscles. Gene expression of the myosin heavy chain isoform, MHCIIx, was increased by cortisol infusion and reduced by adrenalectomy in the BF alone. These findings show that cortisol has a muscle-specific role in prepartum maturation of mitochondrial OXPHOS capacity with important implications for the health of neonates born pre-term or after intrauterine glucocorticoid overexposure.

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Muscle growth in sheep

Lohse

1978

Vet Res Commun

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Growth rates of muscle relative to empty body weight were computed for the Peppin Merino, a breed of sheep considered unimproved for meat production. Rates of muscle increase in the Merino sheep were comparable ta growth coefficients reported far the Ramney and Southdown breeds which were tabulated separately by sex. Pooled data for the Lincoln~ Hampshire, Southdown, Suffolk and Welsh breeds were analyzed relative to empty body weight.No significant difference in muscle growth rates were found in direct comparisons based on "starved" body weights for the Romney and Southdown breeds (Fourie et al, 1970). From the standpoint of conformation these breeds might be expected to differ in muscle growth rate as the Romney is considered o "leggy" sheep and the Southdown a "blocky" animal. Growth coefficients for muscle in the Romney~ Southdown and several other breeds were very similar to the Peppin Merino.

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Growth and development of sheep

Cited by 12 publications

References 6 publications

Developmental programming of mitochondrial substrate metabolism in skeletal muscle of adult sheep by cortisol exposure before birth

Developmental programming of mitochondrial substrate metabolism in skeletal muscle of adult sheep by cortisol exposure before birth

Glucocorticoid maturation of mitochondrial respiratory capacity in skeletal muscle before birth

Muscle growth in sheep

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