White 2017 J Anim Sci
|Influence of temperament on skeletal muscle mitochondrial capacity of Brahman cows.|
Link: Open Access]
Event: J Anim Sci
To investigate a potential relationship between animal temperament and mitochondrial function, 5-yr-old Brahman cows were stratified into one of three temperament groups based on herdsman scores: T1 (n = 4; calm), T2 (n = 4; normal), or T3 (n = 4; temperamental). The cows were processed at the departmental meats lab and samples from the longissimus dorsi (LD) and semitendinous muscles were collected. All samples were assessed for mitochondrial density (via citrate synthase activity) and function (via cytochrome c oxidase activity); samples from the LD were also evaluated for mitochondrial capacity utilizing high-resolution respirometry. Data were analyzed using the MIXED procedure of SAS (9.4). Relative to mg of tissue (integrative mitochondrial capacity), temperamental cattle (T3) had greater state 3 oxidative phosphorylation capacity with complex I substrates (PCI), PCI plus complex II substrates (PCI+II), maximum electron transport capacity (ECI+II), and ECII than T1 (P = 0.009, P = 0.03, P = 0.02, and P = 0.04 for PCI, PCI+II, ECI+II, and ECII, respectively) or T2 (P = 0.03, P = 0.02, P = 0.03, and P = 0.03 for PCI, PCI+II, ECI+II, and ECII, respectively). Temperamental cattle (T3) also had a higher fractional control ratio of PCI+II (0.890 ± 0.023) than T2 (0.780 ± 0.025; P = 0.02), with T1 being intermediate (0.814 ± 0.023). This indicates a greater contribution of complex II to oxidative phosphorylation and energy production in temperamental animals, the effects of which are unknown at this time. Temperamental animals (T3) also had the greatest citrate synthase activity across muscle groups (9.49 ± 0.70 nmol/min*mg tissue) compared to T1 (6.44 ± 0.68; P = 0.009) or T2 (5.29 ± 0.59; P = 0.0008), indicating greater skeletal muscle mitochondrial density in T3. Intrinsic mitochondrial capacity (relative to CS activity) and cytochrome c oxidase activity (mitochondrial function) were not different between muscles, nor between temperament groups. Research is needed to clarify the significance of different patterns of energy production in temperamental cattle. Further, skeletal muscle mitochondrial capacity may be a useful early indicator of animal performance and carcass quality at harvest.
Labels: MiParea: Respiration, mt-Biogenesis;mt-density
Organism: Bovines Tissue;cell: Skeletal muscle
Coupling state: OXPHOS, ET Pathway: N, S, NS HRR: Oxygraph-2k