Browsing by Author "Wicks, Jordan C."

Now showing 1 - 4 of 4
  • Thumbnail Image
    Determining muscle plasticity and meat quality development of low-input extended fed market-ready steers
    Wicks, Jordan C.; Wivell, Alexis L.; Beline, Mariane; Zumbaugh, Morgan D.; Bodmer, Jocelyn S.; Yen, Con-Ning; Johnson-Schuster, Chantal; Wilson, Thomas B.; Greiner, Scott P.; Johnson, Sally E.; Shi, Tim H.; Silva, Saulo Luz; Gerrard, David E. (Oxford University Press, 2024-05-02)
    In March 2020, the World Health Organization declared COVID-19 a pandemic, which ultimately led to many meat processors temporarily shutting down or reducing processing capacity. This backlog in processing capacity forced many feedlots to retain cattle for longer periods of time and assume the risk of major market fluctuations. The aim of this study was to understand how a dietary insult affects meat quality and muscle metabolism in market-ready steers (590 kg). Sixteen market-ready (590 kg) commercial Angus crossbred steers were subjected to a maintenance diet of either forage or grain for 60 d. Longissimus lumborum (LL) muscle samples were collected immediately postmortem and processed for characteristics reflecting the underlying muscle fiber type and energy state of the tissue. Despite cattle being subjected to a 60-d feeding period, there were no detectable differences (P > 0.05) in carcass characteristics, color of lean, or ultimate pH (pHu). Moreover, our data show that muscle plasticity is rather resilient, as reflected by lack of significance (P > 0.05) in oxidative and glycolytic enzymes, myosin heavy chain isoforms (MyHC), myoglobin, and mitochondrial DNA (mtDNA) contents. These data show that market-ready steers are capable of withstanding a low-input feeding strategy up to 60 d without dramatically impacting underlying muscle characteristics and meat quality development.
  • Thumbnail Image
    Mitochondrial Abundance and Function Differ Across Muscle Within Species
    Yen, Con-Ning; Bodmer, Jocelyn S.; Wicks, Jordan C.; Zumbaugh, Morgan D.; Persia, Michael E.; Shi, Tim H.; Gerrard, David E. (MDPI, 2024-10-16)
    Background: Mitochondria are considered the powerhouse of cells, and skeletal muscle cells are no exception. However, information regarding muscle mitochondria from different species is limited. Methods: Different muscles from cattle, pigs and chickens were analyzed for mitochondrial DNA (mtDNA), protein and oxygen consumption. Results: Bovine oxidative muscle mitochondria contain greater mtDNA (p < 0.05), protein (succinate dehydrogenase, SDHA, p < 0.01; citrate synthase, CS, p < 0.01; complex I, CI, p < 0.05), and oxygen consumption (p < 0.01) than their glycolytic counterpart. Likewise, porcine oxidative muscle contains greater mtDNA (p < 0.01), mitochondrial proteins (SDHA, p < 0.05; CS, p < 0.001; CI, p < 0.01) and oxidative phosphorylation capacity (OXPHOS, p < 0.05) in comparison to glycolytic muscle. However, avian oxidative skeletal muscle showed no differences in absolute mtDNA, SDHA, CI, complex II, lactate dehydrogenase, or glyceraldehyde 3 phosphate dehydrogenase compared to their glycolytic counterpart. Even so, avian mitochondria isolated from oxidative muscles had greater OXPHOS capacity (p < 0.05) than glycolytic muscle. Conclusions: These data show avian mitochondria function is independent of absolute mtDNA content and protein abundance, and argue that multiple levels of inquiry are warranted to determine the wholistic role of mitochondria in skeletal muscle.
  • Thumbnail Image
    Postmortem Metabolism and Pork Quality Development Are Affected by Electrical Stimulation across Three Genetic Lines
    Spires, Matthew D.; Bodmer, Jocelyn S.; Beline, Mariane; Wicks, Jordan C.; Zumbaugh, Morgan D.; Shi, Tim Hao; Reichert, Brian T.; Schinckel, Allan P.; Grant, Alan L.; Gerrard, David E. (MDPI, 2023-08-11)
    Variations in postmortem metabolism in muscle impact pork quality development. Curiously, some genetic lines are more refractile to adverse pork quality development than others and may regulate energy metabolism differently. The aim of this study was to challenge pork carcasses from different genetic populations with electrical stimulation (ES) to determine how postmortem metabolism varies with genetic line and explore control points that reside in glycolysis in dying muscle. Three genetic populations (GP) were subjected to ES (100 V or 200 V, 13 pulses, 2 s on/2 s off) at 15- or 25-min post-exsanguination, or no stimulation (NS). Genetic population affected relative muscle relative abundance of different myosin heavy chains, glycogen, G6P, and lactate concentrations. Genetic lines responded similarly to ES, but a comparison of ES treatment groups revealed a trend for an interaction between voltage, time of ES, and time postmortem. Higher voltage accelerated pH decline at 20 min up to 60 min postmortem. Trends in color and firmness scores and L* values were consistent with pH and metabolite data. These data show that genetic populations respond differently to postmortem perturbation by altering glycolytic flux and suggest differences in postmortem glycolysis may be partially responsible for differences in meat quality between genetic populations, though not entirely.
  • Thumbnail Image
    Understanding Beef Quality Development and Different Feeding Regimes
    Wicks, Jordan C. (Virginia Tech, 2023-09-06)
    Understanding Beef Quality Development and Different Feeding Regimes Jordan Christie Wicks ABSTRACT Consumption of beef is expected to increase as the world approaches nearly 9 billion inhabitants by the year 2050, adding unprecedented challenges to the future beef industry. Even so, maintaining quality will still be of utmost importance for producers for two reasons. First, the majority of US cattle are sold on the "grid", which offers both premiums and financial penalties based on quality grades. Second, consumers demand quality. Herein, we explored alternative, cost-saving feeding strategies that impact muscle biochemistry and ultimate meat quality in an effort to determine the most feasible management responses during times of sporadic markets. Our results show that reducing feed inputs from intensive feeding (grain-finished) regimes to maintenance diets of forage or grain up to 60 d had minimal effect on metabolic properties of muscle, thus preserving both quality and yield grades. Specifically, muscle metabolism remained largely unchanged, as indicated by lack of significance in oxidative and glycolytic proteins such as succinate dehydrogenase (SDH), citrate synthase (CS), lactate dehydrogenase (LDH), and phosphofructokinase-1 (PFK-1). Additionally, because maintenance rations were fed, we found no difference in non-esterified fatty acid (NEFA) concentration, or O-linked- β-N-acetylglucosamine (O-GlcNAc) protein abundance suggesting a longer or more aggressive feeding approach may be required to evoke such nutrient based muscle and quality differences. Because quality is important and is a factor for optimal pricing at market, intensive feeding practices are often needed to meet such standards. Still, as the cost of feeding increases, producers struggle to balance quality and profitability. To that end, we evaluated carcass quality of cattle subjected to a reduction of time on feed by 30 d, and found quality, yield and color were similar to that of cattle intensively fed for 120 days. Although, little differences were noted between indicators of postmortem metabolism, short-fed (SF) cattle showed a trend for greater adenosine monophosphate deaminase 1 (AMPD1), and significant difference in the expression of myosin heavy chain isoform (MyHC) IIX suggesting muscle of SF cattle is transiting away from that of grass-fed (CON) cattle. Even so, SF cattle proved to have similar color and quality to cattle fed for 120 days, or more traditionally fed. While we failed to detect differences in muscle between days on feed compared to that of CON (grass-fed), we observed differences in quality and yield between long fed and grass-fed cattle. These data suggest variances in quality may be a result of underlying mechanisms yet to be explained. Therefore, we explored the hallmark biomarkers credited for beef quality development. Despite significant differences in quality and yield grades, data resulted in no differences in myoglobin, oxidative or glycolytic proteins, or calpain-1 and calpastatin between varying phases of growth. However, based on our complementary transcriptomics data, we found linear trends in gene expression related to adipogenesis and muscle hypertrophy, implying these differences may simply be a result of growth rather than muscle function. When taken together, our data suggests severe nutrient restrictions may be required to evoke such a shift in muscle that leads to exacerbated differences in quality. A greater understanding of those mechanisms that drive meat quality development from a conventional grain feeding perspective may prove impactful for the future of our industry.