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RAPID COMMUNICATION: Differential skeletal muscle mitochondrial characteristics of weanling racing-bred horses

Responses of equine skeletal muscle characteristics to growth and training have been shown to differ between breeds. These differential responses may arise in part because muscle fiber type and mitochondrial density differ between breeds, even in untrained racing-bred horses. However, it is not know...

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Autores principales: Latham, Christine M, Fenger, Clara K, White, Sarah H
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6667244/
http://dx.doi.org/10.1093/jas/skz203
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author Latham, Christine M
Fenger, Clara K
White, Sarah H
author_facet Latham, Christine M
Fenger, Clara K
White, Sarah H
author_sort Latham, Christine M
collection PubMed
description Responses of equine skeletal muscle characteristics to growth and training have been shown to differ between breeds. These differential responses may arise in part because muscle fiber type and mitochondrial density differ between breeds, even in untrained racing-bred horses. However, it is not known when these breed-specific differences manifest. To test the hypothesis that weanling Standardbreds (SB) and Thoroughbreds (TB) would have higher mitochondrial measures than Quarter Horses (QH), gluteus medius samples were collected from SB (mean ± SD; 6.2 ± 1.0 mo; n = 10), TB (6.1 ± 0.5 mo; n = 12), and QH (7.4 ± 0.6 mo; n = 10). Citrate synthase (CS) and cytochrome c oxidase (CCO) activities were assessed as markers of mitochondrial density and function, respectively. Mitochondrial oxidative (P) and electron transport system (E) capacities were assessed by high-resolution respirometry (HRR). Data for CCO and HRR are expressed as integrated (per mg protein and per mg tissue wet weight, respectively) and intrinsic (per unit CS). Data were analyzed using PROC MIXED in SAS v 9.4 with breed as a fixed effect. Mitochondrial density (CS) was higher for SB and TB than QH (P ≤ 0.0007). Mitochondrial function (integrated and intrinsic CCO) was higher in TB and QH than SB (P ≤ 0.01). Integrated CCO was also higher in TB than QH (P < 0.0001). However, SB had higher integrated maximum P (P(CI+II)) and E (E(CI+II)) than QH (P ≤ 0.02) and greater integrated and intrinsic complex II-supported E (E(CII)) than both QH and TB (P ≤ 0.02), whereas TB exhibited higher integrated P with complex I substrates (P(CI)) than SB and QH (P ≤ 0.003) and higher integrated P(CI+II) and E(CI+II) than QH (P ≤ 0.02). In agreement, TB and QH had higher contribution of complex I (CI) to max E than SB (P ≤ 0.001), whereas SB had higher contribution of CII than QH and TB (P ≤ 0.002). Despite having higher mitochondrial density than QH and TB, SB showed lower CCO activity and differences in contribution of complexes to oxidative and electron transport system capacities. Breed differences in mitochondrial parameters are present early in life and should be considered when developing feeding, training, medication, and management practices.
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spelling pubmed-66672442019-08-05 RAPID COMMUNICATION: Differential skeletal muscle mitochondrial characteristics of weanling racing-bred horses Latham, Christine M Fenger, Clara K White, Sarah H J Anim Sci Featured Collection Responses of equine skeletal muscle characteristics to growth and training have been shown to differ between breeds. These differential responses may arise in part because muscle fiber type and mitochondrial density differ between breeds, even in untrained racing-bred horses. However, it is not known when these breed-specific differences manifest. To test the hypothesis that weanling Standardbreds (SB) and Thoroughbreds (TB) would have higher mitochondrial measures than Quarter Horses (QH), gluteus medius samples were collected from SB (mean ± SD; 6.2 ± 1.0 mo; n = 10), TB (6.1 ± 0.5 mo; n = 12), and QH (7.4 ± 0.6 mo; n = 10). Citrate synthase (CS) and cytochrome c oxidase (CCO) activities were assessed as markers of mitochondrial density and function, respectively. Mitochondrial oxidative (P) and electron transport system (E) capacities were assessed by high-resolution respirometry (HRR). Data for CCO and HRR are expressed as integrated (per mg protein and per mg tissue wet weight, respectively) and intrinsic (per unit CS). Data were analyzed using PROC MIXED in SAS v 9.4 with breed as a fixed effect. Mitochondrial density (CS) was higher for SB and TB than QH (P ≤ 0.0007). Mitochondrial function (integrated and intrinsic CCO) was higher in TB and QH than SB (P ≤ 0.01). Integrated CCO was also higher in TB than QH (P < 0.0001). However, SB had higher integrated maximum P (P(CI+II)) and E (E(CI+II)) than QH (P ≤ 0.02) and greater integrated and intrinsic complex II-supported E (E(CII)) than both QH and TB (P ≤ 0.02), whereas TB exhibited higher integrated P with complex I substrates (P(CI)) than SB and QH (P ≤ 0.003) and higher integrated P(CI+II) and E(CI+II) than QH (P ≤ 0.02). In agreement, TB and QH had higher contribution of complex I (CI) to max E than SB (P ≤ 0.001), whereas SB had higher contribution of CII than QH and TB (P ≤ 0.002). Despite having higher mitochondrial density than QH and TB, SB showed lower CCO activity and differences in contribution of complexes to oxidative and electron transport system capacities. Breed differences in mitochondrial parameters are present early in life and should be considered when developing feeding, training, medication, and management practices. Oxford University Press 2019-08 2019-07-03 /pmc/articles/PMC6667244/ http://dx.doi.org/10.1093/jas/skz203 Text en © The Author(s) 2019. Published by Oxford University Press on behalf of the American Society of Animal Science. http://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com.
spellingShingle Featured Collection
Latham, Christine M
Fenger, Clara K
White, Sarah H
RAPID COMMUNICATION: Differential skeletal muscle mitochondrial characteristics of weanling racing-bred horses
title RAPID COMMUNICATION: Differential skeletal muscle mitochondrial characteristics of weanling racing-bred horses
title_full RAPID COMMUNICATION: Differential skeletal muscle mitochondrial characteristics of weanling racing-bred horses
title_fullStr RAPID COMMUNICATION: Differential skeletal muscle mitochondrial characteristics of weanling racing-bred horses
title_full_unstemmed RAPID COMMUNICATION: Differential skeletal muscle mitochondrial characteristics of weanling racing-bred horses
title_short RAPID COMMUNICATION: Differential skeletal muscle mitochondrial characteristics of weanling racing-bred horses
title_sort rapid communication: differential skeletal muscle mitochondrial characteristics of weanling racing-bred horses
topic Featured Collection
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6667244/
http://dx.doi.org/10.1093/jas/skz203
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