175 research outputs found
Ractopamine HCl improved cardiac hypertrophy but not poor growth, metabolic inefficiency, or greater white blood cells associated with heat stress in concentrate-fed lambs
Heat stress decreases livestock performance and well-being (Hahn, 1999; Nienaber and Hahn, 2007), causes metabolic dysfunction that decreases growth efficiency (O’Brien et al., 2010), and alters cardiovascular function (Crandall et al., 2008). Each year, heat stress costs the livestock industry up to $2.5 billion (St-Pierre et al., 2003). Ractopamine HCl acts as a nutrient repartitioning agent (Beermann, 2002); classified as a β adrenergic agonist (βAA), it shares pharmacological properties with adrenaline (Beermann, 2002). βAA increase muscle mass and decreases fat deposition through unknown mechanisms (Beermann, 2002). In feedlot cattle, they increase growth efficiency and improve carcass yield and merit (Scramlin et al., 2010; Buntyn et al., 2017), which increases profit and allows more meat to be produced from fewer animals. However, because βAA act via a stress system, it is unclear how the products affect animals under stress conditions. β1AA and β2AA can also cause tachycardia, heart palpitations, and arrhythmias (Sears, 2002). We hypothesize that β1AA combined with heat stress may overstimulate the adrenergic system, resulting is metabolic dysfunction and decreased performance. Sheep are a common model for cattle, and thus, the objective of this study was to determine the impact of ractopamine HCl on health and cardiovascular parameters, growth, and metabolic efficiency in feeder lambs
Real supermodels wear wool: summarizing the impact of the pregnant sheep as an animal model for adaptive fetal programming
• Intrauterine growth restriction (IUGR) continues to be a global epidemic that is associated with high early-life mortality rates and greater risk for developing metabolic disorders that lower length and quality of life in affected individuals.
• Fetal programming of muscle growth and metabolic function associated with IUGR is often comparable among nonlitter bearing mammalian species, which allows much of the information learned in domestic animal models to be applicable to humans (and other animals).
• Recent studies in sheep models of IUGR have begun to uncover the molecular mechanisms linking adaptive fetal programming and metabolic dysfunction.
• Targets of adaptive fetal programming indicated by sheep studies include adrenergic and inflammatory pathways that regulate skeletal muscle growth and glucose metabolism. Adaptive changes in these pathways represent potential focus areas for prenatal interventions or postnatal treatments to improve outcomes in IUGR-born offspring
Body composition estimated by bioelectrical impedance analyses is diminished by prenatal stress in neonatal lambs and by heat stress in feedlot wethers
Body composition correlates to carcass value in livestock, which makes the ability to accurately estimate body composition in the live animal beneficial (Berg and Marchello, 1994). Bioelectrical impedance analysis (BIA) is a clinical tool used to assess body composition in humans (Lukaski et al., 1985), but its use in livestock has been minimal. Lean and fat content contribute to profitability for livestock producers, and poor body composition can be caused by stress that occurs either during in utero development (De Blasio et al., 2007) or during postnatal growth (Boyd et al., 2015). Maternal hyperthermia-induced placental insufficiency (Brown et al., 2015) and sustained maternal inflammation (Cadaret et al., 2018) are two established causes of intrauterine growth restriction (IUGR). IUGR-born animals are characterized by asymmetrical growth restriction that alters lifelong body composition due to impaired muscle growth capacity (Yates et al., 2018). In addition, acute heat stress during periods of peak postnatal growth can alter body composition in livestock (Boyd et al., 2015). We postulate that BIA can detect these changes in the live animal. Thus, the objective of this study was to determine whether BIA measurements can predict changes to body composition in live neonatal lambs exposed to intrauterine stress and in heat-stressed feedlot lambs
Maternal inflammation at 0.7 gestation in ewes leads to intrauterine growth restriction and impaired glucose metabolism in offspring at 30 d of age
Fetal programming associated with intrauterine growth restriction (IUGR) leads to lifelong deficits in growth and metabolic function (Hales and Barker, 2013). IUGR arises when fetuses respond to poor in utero conditions by developing adaptations that repartition nutrients to critical tissues and away from skeletal muscle (Yates et al., 2012, 2018). This fetal programming is beneficial in utero but leads to persistent reductions in muscle mass and glucose homeostasis in offspring (DeFronzo et al., 1981). Recent studies by our laboratory in sheep and rats demonstrate that maternal inflammation during gestation induces fetal inflammatory adaptations that impair growth and disrupt muscle glucose metabolism (Cadaret et al., 2017, 2018). IUGR fetal skeletal muscle exhibits indicators of enhanced inflammatory sensitivity, which could disrupt glucose uptake and oxidation (Yates et al., 2016; Cadaret et al., 2018). Enhanced inflammatory responsiveness would help explain growth and metabolic deficits observed in IUGR offspring. We hypothesize that fetal programming induced by maternal inflammation persists in offspring and contributes to impaired growth and glucose metabolism at 30 d. Therefore, the objective of this study was to determine whether sustained maternal inflammation induced by bacterial endotoxin at 0.7 gestation leads to fetal programming that contributes to deficits in growth and glucose metabolism in offspring
Investigation of the skeletal muscle transcriptome in lambs fed β adrenergic agonists and subjected to heat stress for 21 d
Dietary β-adrenergic agonists (β-AA) are used in livestock to increase muscle protein accretion and decrease adipose deposition during the last 20 to 40 d of the finishing period (Johnson et al., 2014). These β-AA act through specific seven transmembrane receptors and are classified by the receptor isoform to which they primarily bind (Mersmann, 1998). Two β-AA are approved for use in beef cattle in the United States: ractopamine HCl (RAC, β1 agonist) and zilpaterol HCl (ZH, β2 agonist) (Johnson et al., 2014). Supplementation of β-AA increases efficiency of the animal and results in a leaner carcass (Elam et al., 2009). However, the skeletal muscle’s genomic response to these treatments is not well understood. Heat stress (HS) has long been a major concern in the livestock industry. HS occurs when an animal’s body temperature rises above its thermoneutral zone, at which point the heat load exceeds the animal’s capacity for heat dissipation (Bernabucci et al., 2010), resulting in decreased feed intake and poor performance (Marai et al., 2007). Therefore, growth and production decrease during HS, affecting economically important carcass and reproductive traits. As a result, millions of dollars are lost each year due to HS (Renaudeau et al., 2012). Individually, HS and β-AA supplementation have antagonistic effects on muscle growth. However, there is a gap in understanding of the genomic mechanisms through which animals respond to these factors individually and in concert. The purpose of this study is to investigate the effects of β-AA, HS, and their interaction in skeletal muscle using transcriptomic analyses
Distributed Disdrometer and Rain Gauge Measurement Infrastructure Developed for GPM Ground Validation
Global Precipitation Mission (GPM)retrieval algorithm validation requires datasets characterizing the 4-D structure, variability, and correlation properties of hydrometeor particle size distributions (PSD) and accumulations over satellite fields of view (FOV;<10 km). Collection of this data provides a means to assess retrieval errors related to beam filling and algorithm PSD assumptions. Hence, GPM Ground Validation is developing a deployable network of precipitation gauges and disdrometers to provide fine-scale measurements of PSD and precipitation accumulation variability. These observations will be combined with dual-frequency, polarimetric, and profiling radar data in a bootstrapping fashion to extend validated PSD measurements to a large coverage domain. Accordingly, a total of 24 Parsivel disdrometers(PD), 5 3rd-generation 2D Video Disdrometers (2DVD), 70 tipping bucket rain gauges (TBRG),9 weighing gauges, 7 Hot-Plate precipitation sensors (HP), and 3 Micro Rain Radars (MRR) have been procured. In liquid precipitation the suite of TBRG, PD and 2DVD instruments will quantify a broad spectrum of rain rate and PSD variability at sub-kilometer scales. In the envisioned network configuration 5 2DVDs will act as reference points for 16 collocated PD and TBRG measurements. We find that PD measurements provide similar measures of the rain PSD as observed with collocated 2DVDs (e.g., D0, Nw) for rain rates less than 15 mm/hr. For heavier rain rates we will rely on 2DVDs for PSD information. For snowfall we will combine point-redundant observations of SWER distributed over three or more locations within a FOV. Each location will contain at least one fenced weighing gauge, one HP, two PDs, and a 2DVD. MRRs will also be located at each site to extend the measurement to the column. By collecting SWER measurements using different instrument types that employ different measurement techniques our objective is to separate measurement uncertainty from natural variability in SWER and PSD. As demonstrated using C3VP polarimetric radar, gauge, and 2DVD/PD datasets these measurements can be combined to bootstrap an area wide SWER estimate via constrained modification of density-diameter and radar reflectivity-snowfall relationships. These data will be combined with snowpack, airborne microphysics, radar, radiometer, and tropospheric sounding data to refine GPM snowfall retrievals. The gauge and disdrometer instruments are being developed to operate autonomously when necessary using solar power and wireless communications. These systems will be deployed in numerous field campaigns through 2016. Planned deployment of these systems include field campaigns in Finland (2010), Oklahoma (2011), Canada (2012) and North Carolina (2013). GPM will also deploy 20 pairs of TBRGs within a 25 km2 region along the Virginia coast under NASA NPOL radar coverage in order to quantify errors in point-area rainfall measurements
Deficits in growth, muscle mass, and body composition following placental insufficiency-induced intrauterine growth restriction persisted in lambs at 60 d of age but were improved by daily clenbuterol supplementation
Low birthweight in livestock results from stress-induced intrauterine growth restriction (IUGR; Yates et al., 2018). IUGR fetuses exhibit diminished muscle growth that persists in the neonatal stage, leading to asymmetric body composition and decreased weight gain (Cadaret et al., 2019). Ultimately, low birthweight diminishes yield and carcass merit at harvest (Greenwood et al., 2000), making effective postnatal treatment strategies to improve IUGR growth outcomes necessary. In this study, we examined the benefits of injecting the β2 agonist clenbuterol daily to target adrenergic adaptations that we previously observed in IUGR muscle (Posont et al., 2018; Yates et al., 2018). We hypothesized that IUGRinduced growth deficits would persist at the juvenile stage, manifesting in inferior body composition and carcass traits. We also postulated that clenbuterol would at least partially recover growth and body symmetry. Our objective was to test this hypothesis by assessing growth metrics and body composition in IUGR-born lambs hand-reared to 60 d of age and supplemented daily with injectable clenbuterol
African American community of southeast Rocky Mount, North Carolina : an action-oriented community diagnosis final report
During the fall of 2007 and spring of 2008, a team of five graduate students from the University of North Carolina at Chapel Hill’s School of Public Health conducted an Action-Oriented Community Diagnosis (AOCD) of the community in Southeast Rocky Mount. AOCD is a component of the curriculum for graduate students in the Department of Health Behavior and Health Education. Historically, the teaching team has been approached by community members seeking an assessment of their community. These community members then act as preceptors to student teams, introducing them to the community and aiding in our AOCD process. The process itself involves interacting with community members and service providers to systematically collect information about community strengths and challenges. The student team in Rocky Mount interviewed 19 service providers and 14 community members, conducted 2 focus groups and attended 12 community events. On April 12, the team hosted a community forum in Southeast Rocky Mount (SERM), at which findings were presented back to the community. Through break-out groups focused on discussing particular emerging themes, community members and service providers created action steps to address these themes. Hence, the AOCD process transformed from a diagnosis made by outsiders to a series of commitments by community participants to addressing their collective needs. At the beginning of the AOCD process, the student team conducted a secondary data review to learn more about Southeast Rocky Mount’s health, economics, crime and education status. The team then compared this data to that of the city of Rocky Mount, Edgecombe County and/or North Carolina depending upon the sources of data available. Rocky Mount is divided between two counties, Nash and Edgecombe, which at times affected the availability of data. The team also collected primary data through interviews and focus groups, which were guided by a predetermined set of questions. These discussions with community members and service providers provided much richer qualitative information. Team members transcribed and coded this data to determine which themes occurred most frequently. Identified strengths of the community included the people within the community and the history of a strong, thriving African American community in the area, among others. Meanwhile, challenges identified included: disparities between resources available in Nash County and Edgecombe County; lack of reliable public transportation; limited educational opportunities for youth and young adults; limited recreational and enrichment activities for youth; limited employment opportunities; dilapidated and sub-standard housing conditions; crime due to drugs and gang violence; and limited collaboration between community resources. Through consideration of these strengths and challenges, along with the coded interview data, the student team developed a list of emerging themes. These themes were presented to the eight community members and service providers that made up the forum planning committee. These members helped select the final themes to be used at the April forum. The initial list included: Youth, Education, Employment, Transportation, Crime, Housing/Cost of living, Parenting, and Communication between existing community resources. These eight preliminary themes were then narrowed down to the final five themes that we presented at the community form. The final themes selected for presentation to the community were: Youth, Employment, Connecting Community Resources, Crime, Housing. Approximately 65 individuals attended the community forum. Overall, participants were enthusiastic and optimistic when discussing the selected themes. At the end of the day, action steps were created for each theme and individuals personally committed to completing those steps. A future date was set for the community members and service providers to meet, without the student team, so that the AOCD process could continue within and among the community.Master of Public Healt
Beta-adrenergic agonists increase maximal output of oxidative phosphorylation in bovine satellite cells
Beta-adrenergic agonists (βAA), Ractopamine HCl (RH) and Zilpaterol HCl (ZH), are FDAapproved supplements utilized in pigs and cattle to improve growth performance, carcass weight, and longissimus muscle area (Arp et al., 2014; Lean et al., 2014). Previous studies within our group have focused on understanding molecular changes in skeletal muscle due to βAA supplementation. This work has shown that βAA supplementation increases glucose oxidation in muscle from thermoneutral and heat-stressed lambs (Barnes et al., 2019) and in rat skeletal muscle stimulated with ZH (Cadaret et al., 2017). Skeletal muscle transcriptomics of lambs supplemented ZH revealed upregulation of genes associated with the callipyge phenotype of sheep (Yu et al., 2018) as well as the upregulation of mitochondrial solute carrier SLC25A25 (Kubik et al., 2018). SLC25A25 is a Ca2+ sensitive ATP-Mg2+/Pi inner mitochondrial membrane solute transporter. Due to the role of the mitochondria in metabolism and the results of prior transcriptomics studies, the objective of this study was to understand how βAA affect mitochondrial function of bovine skeletal muscle stem (i.e., satellite) cells. We hypothesized that βAA would improve efficiency and ATP production capacity of muscle stem cells by modifying mitochondrial function
Ractopamine HCl improved cardiac hypertrophy but not poor growth, metabolic inefficiency, or greater white blood cells associated with heat stress in concentrate-fed lambs
Heat stress decreases livestock performance and well-being (Hahn, 1999; Nienaber and Hahn, 2007), causes metabolic dysfunction that decreases growth efficiency (O’Brien et al., 2010), and alters cardiovascular function (Crandall et al., 2008). Each year, heat stress costs the livestock industry up to $2.5 billion (St-Pierre et al., 2003). Ractopamine HCl acts as a nutrient repartitioning agent (Beermann, 2002); classified as a β adrenergic agonist (βAA), it shares pharmacological properties with adrenaline (Beermann, 2002). βAA increase muscle mass and decreases fat deposition through unknown mechanisms (Beermann, 2002). In feedlot cattle, they increase growth efficiency and improve carcass yield and merit (Scramlin et al., 2010; Buntyn et al., 2017), which increases profit and allows more meat to be produced from fewer animals. However, because βAA act via a stress system, it is unclear how the products affect animals under stress conditions. β1AA and β2AA can also cause tachycardia, heart palpitations, and arrhythmias (Sears, 2002). We hypothesize that β1AA combined with heat stress may overstimulate the adrenergic system, resulting is metabolic dysfunction and decreased performance. Sheep are a common model for cattle, and thus, the objective of this study was to determine the impact of ractopamine HCl on health and cardiovascular parameters, growth, and metabolic efficiency in feeder lambs
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