Browsing by Author "Coleman, Stephen, committee member"
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Item Open Access Circulating micro RNA in insulin resistant horses(Colorado State University. Libraries, 2018) da Costa Santos, Hugo F., author; Hess, Tanja, advisor; Landolt, Gabriele, committee member; Bruemmer, Jason, committee member; Coleman, Stephen, committee member; Engle, Terry, committee memberInsulin resistance is a prevalent pathophysiological disorder among domestic horses and is associated with many other conditions such as abnormal adiposity, chronic low-grade systemic inflammation, equine metabolic syndrome, and pituitary pars intermedia dysfunction. However, the processes leading to equine insulin resistance and associated conditions remain a subject of study. Studies in human and laboratory animals have shown that a class of small non-coding RNAs, known as microRNAs (miRNAs), are involved in the regulation of many biological processes and are associated with many diseases. MiRNAs have emerged as potential biomarkers in studies for the diagnosis and prognosis of many diseases, including type 2 diabetes and metabolic syndrome. Profiling circulating miRNAs allows researchers to understand further the mechanisms involved in many diseases, including type 2 diabetes mellitus and metabolic syndrome in humans, and it has excellent potential for equine medicine. In our pilot study, we hypothesized that insulin resistant horses would have a different circulating miRNA profile than those that are healthy. 6 mares were selected from an initial population to represent the most insulin-sensitive (n = 3) and insulin resistant (n = 3) states. Serum samples were collected for miRNA profiling of these animals, investigating the presence and relative amount of 340 equine miRNAs. Results showed different miRNA profiles between groups, with a total of 14 miRNAs differently expressed between insulin resistant and insulin sensitive animals. Furthermore, results of this preliminary study suggested circulating miRNA profiles as potential new tools for evaluating the mechanisms of insulin resistance in horses and the development of novel diagnosis and treatment methods for this condition in equines. The current study aimed to follow up the pilot study by increasing the number of animals undergoing miRNA profiling and including both horses and ponies for testing. It was hypothesized that insulin resistant animals (horses and ponies) would have a different circulating miRNA profile than those that are healthy. Additionally, circulating miRNA profiles of horses and ponies were also compared. Two initial populations, one of horses and one of ponies, were screened for their insulin sensitivity state using basal proxies for insulin and glucose. Selected animals, 12 non-pregnant Thoroughbred/ Thoroughbred-cross and 12 non-pregnant Welsh/Dartmoor mares were evaluated for insulin sensitivity with the frequent sampling intravenous glucose tolerance test (FSIGTT), and serum samples collected for miRNA profiling. The quantification of miRNAs was done through qRT-PCR analysis performed to investigate the presence and relative amount of 340 equine miRNAs. Confirmation by quantitative real-time polymerase chain reaction revealed that miRNA was present in the serum of all animals. After diagnosis based on the FSIGTT results, mares were divided into groups representing their insulin sensitivity state: insulin sensitive (IS, n = 13, ten horses and three ponies) or insulin resistant (IR, n = 11, two horses and nine ponies) animals, and their miRNA profile compared. Results demonstrated that from the 340 miRNAs analyzed, 13 miRNAs were differentially expressed between insulin resistant and insulin sensitive horses, 15 differently expressed between insulin resistant and insulin sensitive ponies, 17 differently expressed between horses and ponies, and 14 differently expressed between insulin resistant and insulin sensitive animals, horses and ponies combined (p<0.05), with 4 of these miRNAs already noted when comparing horses versus ponies. In the horse groups, three miRNAs were expressed in the insulin resistant group only. Finally, eight circulating miRNAs are proposed as potential regulators of equine insulin resistance. The results of this study, in addition to our preliminary investigation, suggest potential new tools that could be used to understand further the mechanisms involved in equine insulin resistance and associated conditions and for the development of new, practical and efficient diagnosis and prognosis methods for this condition in horses.Item Open Access Comparison of an antioxidant source and antioxidant plus BCAA on athletic performance and post exercise recovery of horses(Colorado State University. Libraries, 2022) Kent, Emily, author; Hess, Tanja, advisor; Coleman, Stephen, committee member; Hamilton, Karyn, committee member; Bruemmer, Jason, committee memberAntioxidant supplementation has been shown to decrease post-exercise oxidative stress but can lead to decreased post-exercise muscle protein synthesis. The objective of this study was to compare the effects of the supplementation with a control feed with low antioxidant content (CON) to a high antioxidant feed (AO), versus a high antioxidant and branched-chain amino acid feed (BCAO) on post-exercise protein synthesis and oxidative stress. Our hypothesis is that supplementing AO with BCAA will reduce oxidative stress without hindering muscle protein synthesis. Eighteen mixed breed conditioned polo horses were assigned to one of the three treatments. All horses consumed the CON diet for 30 days and were then assessed using a lactate threshold test (LT). One hour later and following subsequential LT, horses were assigned to the experimental groups and given their treatments. Follow-up LTs were conducted on days 15 and 30 of supplementation. Blood was collected before, two and four hours after LT, and oxidative stress was assessed by determining glutathione peroxidase, superoxide dismutase and malondialdehyde concentrations by ELISA. Muscle biopsies were taken before and 4 hours after LT and analyzed for the expression of protein synthesis by RT-PCR. Results were analyzed in a mixed model by ANOVA and compared by LSM. A reduction of oxidative stress was found over time (P<0.050) with no treatment effect (P>0.050) when using the measured oxidative stress parameters mentioned above. An upregulation in the production of mRNA transcripts related to muscle protein synthesis after exercise was found for muscle primers CD36, CPT1, PDK4, MyF5, and Myogenin (P<0.050). There was a treatment by exercise effect for MyoD (P=0.0041), where AO was upregulated the most after exercise compared to BCAO and CON. MRF4 had a time by treatment effect (p=0.045) where AO was upregulated from day 0 to day 15 and 30 compared to BCAO and CON. This study demonstrated post-exercise muscle synthesis with no advantage of AO plus BCAA compared to AO.Item Open Access Contraception vaccination for mares and its effects on cyclicity and estrous behavior(Colorado State University. Libraries, 2019) Reisenauer, Ashley, author; Bruemmer, Jason, advisor; Coleman, Stephen, committee member; Eckery, Douglas, committee member; Bouma, Jerry, committee memberOverpopulation is an issue for wild horses due to limited forage and decreasing water sources. Sterilizing mares without surgical ovariectomy would be cost effective and safer. There are currently no vaccines that cause permanent sterility in mares. Bone Morphogenetic Protein 15 (BMP-15) and Growth Differentiation Factor 9 (GDF-9) are oocyte-specific proteins involved in every stage of follicular development from primordial activation through ovulation. This study investigated the effects of a combination vaccine consisting of these oocyte-specific growth factors, GDF-9 and BMP-15, on mare cyclicity and estrous behavior. We hypothesized that immunization against the combination of these two factors would result in no ovarian cyclicity. Mature, fertile Quarter Horse type mares (n=10/group) each of which had successfully carried a foal within the last 24 months were used. The experiment was conducted from February through September 2018. All mares were vaccinated a total of 5 times starting at week 0, continuing at week 6, 12, 18, and 24. Ten mares received the vaccine consisting of both peptides (GDF-9; SEYFKQFLFPQNEC and BMP-15; QAGSMGSEVLGPSREREGPESNQC) and adjuvant (Seppic Montanide™ Pet Gel A), while control mares received adjuvant alone. All vaccinations were administered IM. Ovarian activity and ovulations were recorded by trans-rectal ultrasonography at least once a week and estrous behaviors were evaluated three days a week by interacting individually with a stallion on a tease rail. Follicle diameters were recorded according to measurements and estrous behavior scored on a 6-point scale (0 = hostile toward stallion – 5 = actively seeking stallion with associated behaviors). Jugular blood samples were collected prior to each weekly palpation, and serum was aspirated for further investigation of the progesterone levels. All control mares cycled normally with ovulations associated with estrus at approximately 3-week intervals. None of the 10 treated mares ovulated or grew a follicle larger than 20 mm during the 8-month experimental period. Mixed estrous behaviors were noted in a few mares throughout the study. Low progesterone levels in serum samples confirmed these findings and are associated with the presence and/or lack of detected corpra lutea. Future research will focus on the active duration of the vaccination to determine the length of effectiveness. This vaccination could serve as a long-term contraceptive in wild horse herd populations.Item Open Access Evaluating the equine endometrial transcriptome during maternal recognition of pregnancy(Colorado State University. Libraries, 2018) Klohonatz, Kristin, author; Bruemmer, Jason, advisor; Coleman, Stephen, committee member; Bouma, Gerrit, committee member; Hess, Ann, committee member; Thomas, Milton, committee memberTo view the abstract, please see the full text of the document.Item Open Access Identifying single nucleotide polymorphisms associated with beef cattle terrain-use in the western United States(Colorado State University. Libraries, 2019) Pierce, Courtney F., author; Thomas, Milton, advisor; Speidel, Scott, advisor; Coleman, Stephen, committee member; Enns, R. Mark, committee member; Meiman, Paul, committee memberBeef cattle are drawn to areas with gentle terrain, which may result in heavy grazing near riparian zones and minimal grazing on rugged terrain. Traditional management tools to improve grazing distribution can be costly; therefore, genomic selection has been proposed as a means of improving beef cattle grazing patterns. The objective of this thesis was to identify single nucleotide polymorphisms (SNP) associated with beef cattle terrain-use in the western U.S. Variant detection using RNA-sequencing data obtained from Angus cardiovascular tissues and Brangus reproductive tissues revealed 48 potential causative mutations in five genes that were previously associated with terrain-use indices: SDHAF3, RUSC2, SUPT20H, MAML3, and GRM5. In an additional study, Bayesian multiple-regression was performed using BovineHD genotypes and global positioning system (GPS) data collected from 80 beef cows managed in Arizona, Montana, and New Mexico. Results of this analysis suggested that beef cattle terrain-use was polygenic; however, additional observations were needed to validate the quantitative trait loci (QTL) identified. Subsequent genome-wide association studies (GWAS) were performed for six terrain-use traits using BovineSNP50 genotypes and distribution data collected from a multi-breed population of cattle (n = 330) managed in the western U.S. These analyses identified 32 QTL and 29 putative candidate genes with diverse functions related to hypoxia, heat stress, feed efficiency, weight traits, energy metabolism, and lactation. In conclusion, results presented in this thesis suggested that terrain-use is polygenic and may be improved with genetic selection; however, additional studies are needed to further elucidate the genetic mechanisms underlying terrain-use of beef cattle.Item Open Access Investigating hepatic copper trafficking in beef cattle(Colorado State University. Libraries, 2020) Tillquist, Nicole, author; Engle, Terry, advisor; Coleman, Stephen, committee member; Nair, Mahesh Narayanan, committee member; Torres-Henderson, Camille, committee memberTo view the abstract, please see the full text of the document.Item Open Access Regulatory microRNA delivered to stallion spermatozoa during epididymal maturation(Colorado State University. Libraries, 2016) Twenter, Hannah, author; Bruemmer, Jason, advisor; Bass, Luke, committee member; Bouma, Gerrit, committee member; Coleman, Stephen, committee memberStallion spermatozoa are produced in the seminiferous tubules of the testis. After spermatogenesis, spermatozoa migrate through the seminiferous tubules to the rete testis then efferent ducts which converge to form a single duct within the caput of the epididymis. The epididymis is a convoluted tubule with region-specific luminal profiles. The epididymis consists of three commonly descried regions; caput, corpus, and cauda. Each region performs distinct functions in epididymal maturation of spermatozoa. The caput is responsible for concentration of spermatozoa by reabsorbing excess fluid from the epididymal lumen. The corpus is where majority of maturation occurs as spermatozoa gain motility and shed their cytoplasmic droplet. The cauda primarily serves as a storage site for the spermatozoa until ejaculation or spontaneous emission. All regions of the epididymis are lined with multiple epithelial cell types, each with different functions to provide the ideal luminal environment for the maturation. These epithelial cells also create apical blebs containing small, membranous vesicles named epididymosomes. The apical blebs are released from the apical surface via apocrine secretion and will disintegrate in the lumen, releasing epididymosomes. Epididymosomes transport proteins from the epithelium to the spermatozoa in the lumen. They also contain microRNAs (miRNAs). MicroRNAs are small, non-coding post-transcriptional regulators of mRNAs and can interfere with mRNA transcription through translational repression or degradation. We hypothesize that epididymosomes also transfer miRNA from the epididymal epithelium to spermatozoa. Quantitative real-time polymerase chain reaction was used to determine the miRNA profile of epididymal tissue from the caput and cauda, epididymal spermtozoa from the caput and cauda, and epididymosomes from the caput, proximal corpus, distal corpus, and cauda. Our focus turned to 33 newly-acquired miRNAs with expression specific to the spermatozoa located within the cauda as these are fully mature cells. Comparing the miRNAs present in each sample, 11 miRNAs had a distinct path from epididymal tissue to epididymosomes to spermatozoa, suggesting that miRNAs are transported to spermatozoa from the epididymal epithelium via epididymosomes. Pathway analysis was performed using DIANA tools on the 33 miRNA with expression on in caudal spermatozoa using an a posteriori method with predicted pathways considered significant with P≤0.05. Fifty-one predicted pathways were statistically significant. Some of those predicted pathways suggest a role in cell motility and viability, while others influenced factors in the oocyte or embryo. By developing a better understanding of the mechanisms behind the processes that regulate sperm maturation as well as the roles in embryogenesis better diagnostics for infertility in the horse may be generated.Item Open Access The effects of corn on microRNA expression within horses(Colorado State University. Libraries, 2021) Carver, Clarissa, author; Hess, Tanja, advisor; Bruemmer, Jason E., committee member; Coleman, Stephen, committee member; Landolt, Gabriele, committee memberNutrition has been shown to play a major role in the health of horses in all life stages and levels of work. In recent years the prevalence of equine obesity has increased as more horses are kept in stalls with lower workloads, while receiving high energy and calorically dense feeds like grain, many of which contain corn, in addition to forage. The increase in equine obesity has been accompanied by more cases of metabolic diseases developing, often linked to poor nutrition and diets high in non-structural carbohydrates (NSC). Although more cases of metabolic disorders are emerging there currently are no good biomarkers to diagnose these diseases or identify horses on diets providing them with poor nutrition. Diets high in NSCs have been linked to insulin resistance and laminitis within horses, two of the main components of Equine Metabolic Syndrome (EMS), however nutrigenomic studies looking at the interaction of diets high in NSCs on gene expression, specifically through the regulation of endogenous microRNAs (miRNA) are rare. Recent research on mice and human models has demonstrated the large impact diet has on levels of miRNAs within the body and mRNA targets for these miRNAs resulting in the regulation of gene expression, in addition to identifying miRNAs in circulation that can be used as biomarkers for obesity, type 2 diabetes, and metabolic syndrome. Research has also demonstrated the ability of diet-derived exogenous miRNAs to be absorbed from the digestive tract, appear within circulation, and be taken up by various tissues throughout the body. Diet-derived miRNAs specifically from plants have been detected in tissue and circulating within the blood suggesting the possibility of cross-species gene regulation, but the exact role these miRNAs play physiologically is still unknown. miRNAs are small non-coding molecules that affect post-transcriptional gene regulation and RNA silencing by translational repression or degradation. Previous research revealed that some plant miRNAs could be identified in equine serum exosomes and tissues but was not able to identify a corn specific miRNA within any equine samples. We first hypothesized that diet-derived corn miRNAs can be detected in equine serum and muscle after corn supplementation. For this study twelve mares were blocked by weight and BCS and assigned to one of two treatments (n=6/group): 1) control, (basal diet: 20 lbs./head/d of chopped mixed alfalfa-grass hay and ad libitum mixed grass hay), 2) basal diet supplemented with 1 lb./d steam flaked corn. Muscle biopsies of the Gluteus medius and serum samples were collected from all horses on d0 and d28. Samples were analyzed using real-time RT-qPCR for 3 plant miRNAs. Our results revealed the presence of plant miRNAs in equine total serum and skeletal muscle. Our results also revealed the level of plant miRNAs, including the corn specific miRNA, within circulation vary after ingestion, suggesting plant miRNAs are capable of being taken up by equine tissues. These results are important for understanding how physiological processes may be impacted by diet-derived plant miRNAs. Moreover, these results suggest plant miRNAs could potentially serve a therapeutic role in helping to regulate endogenous gene expression in addition to the nutrients being provided by ingestion. The large impact diet can have on equine health and the association between diets high in NSC and insulin resistance, caused us to be interested in the effects a diet supplemented with corn would have on endogenous miRNAs within the horse. We hypothesized that supplementing horses with corn would alter the endogenous miRNA profiles within both serum and skeletal muscle. For this objective, we utilized the same serum and muscle samples collected for the feed trial horses as the plant miRNAs. Samples were analyzed using real-time RT-qPCR for 277 endogenous equine miRNAs. Our results showed 13 differentially expressed (P<.05) miRNAs in equine serum after 28 days of corn supplementation. Six of these miRNAs (eca-mir16, -4863p, -4865p, -126-3p, -296, and -192), were linked to obesity and/or metabolic disease. Within skeletal muscle, our results showed three miRNAs differentially expressed (P<.05) and three miRNAs with a trend toward differential expression (.05Item Open Access The influence of trace mineral source on reproductive performance in recipient multiparous beef cows(Colorado State University. Libraries, 2022) Thomas, Tyler, author; Engle, Terry, advisor; Hess, Ann, committee member; Coleman, Stephen, committee memberAn experiment was conducted to determine the effects of copper (Cu), cobalt (Co), manganese (Mn), selenium (Se), and zinc (Zn) source on the reproductive parameters of multiparous beef cows. Fifty cow-calf pairs were divided into ten groups (n=5 cow-calf pairs per group) and balanced across groups for animal source, cow weight, calf age, calf sex, and breed type. Each group was randomly assigned to one of the following treatments: 1) Organic trace minerals: 75 mg of Cu/d from Cu proteinate, 8 mg of Co/d from Co proteinate, 105 mg of Mn/d from Mn proteinate, 3 mg of Se/d from Sel-Plex, and 220 mg of Zn/d from Zn proteinate; and 2) Inorganic trace minerals (at two times the NASEM (2016) requirements): 255 mg of Cu/d from CuSO4∙5H20, 2.6 mg of Co/d from CoCO3, 1018 mg of Mn/d from MnSO4, 3 mg Se/d from Na2SeO4, and 763 mg of Zn from ZnSO4∙5H2O. Animals were fed a corn silage – corn stalk-based diet that met or exceeded the NASEM (2016) requirements for gestating beef cows with the exception of Cu, Co, Mn, Se, and Zn. Cows were individually supplemented with their appropriate treatments daily for 89 days, five days after the initiation of estrus synchronization (day 0). Estrus synchronization was achieved through implantation of a progesterone controlled internal drug release (CIDR; Zoetis; impregnated with 1.38 g progesterone) device and 2ml of gonadotropin-releasing hormone (GnRH; Factrel from Zoetis) administered intramuscularly. After seven days, the CIDR was removed, 2 ml lutalyse (HighCon from Zoetis) was administered intramuscularly, and an Estrotect patch was applied for estrus detection. After two additional days, recipient cows were given a second dose (2ml) of GnRH. Eight additional days later, all recipient cows that were synchronized were palpated, and those with a viable corpus luteum (CL) received an embryo as well as a CIDR. The CIDR was removed 15 days later and an Estrotect patch was applied. Expression of estrus was evaluated for the following four days of the experiment. Cows that did not express estrus, and cows that did not maintain a pregnancy from the first embryo, underwent the same estrus synchronization protocol a subsequent time. A licensed veterinarian made pregnancy diagnoses on August 18th, September 12th, and October 8th using an ultrasound, recording each cow as either pregnant or open. Blood samples were collected via jugular venipuncture from each animal on days 0, 16, 43, 68, and 94 of the experiment and analyzed for progesterone, luteinizing hormone, anti-mullerian hormone, follicle-stimulating hormone, and estradiol. However, as animals in this study varied by pregnancy status and days pregnant, mineral status and hormone status were evaluated by time points (TP) defined as TP0: prior to embryo transfer; TP1: day of embryo transfer; TP2: 28-33 days post embryo transfer; TP3: 58-60 days post embryo transfer; and TP4: 84 days post to embryo transfer. There was a treatment by time effect for plasma Cu concentrations (P < .03), with Cu concentrations of the inorganic treatment decreasing (0.89 to 0.76 mg Cu/L) and those of the organic treatment increasing (1.01 to 1.19 mg Cu/L) as the experiment progressed. There were no other significant time or treatment by time effects for plasma trace mineral concentrations. Cows receiving organic trace minerals had greater plasma Se and Cu (P < .0001) concentrations when compared to cows receiving the inorganic trace mineral. Plasma cobalt, manganese, and zinc concentrations were similar between the two treatments (P > 0.1). Pregnancy rates of the inorganic and organic treatments were similar at the conclusion of the trial (66.6% and 62.5%, respectively). Treatment outcomes were also similar (P > 0.10) for embryo transfer attempts, calf birth weights, and days pregnant. There were no treatment or treatment by time interactions for serum progesterone, luteinizing hormone, anti-mullerian hormone, follicle-stimulating hormone, or estradiol concentrations (P > 0.10). The differences in circulating trace elements between treatments did not appear to impact the hormone concentrations or reproductive outcomes in this trial. Further research is needed to further understand the impact of mineral source on reproductive outcomes.