Browsing by Subject "NIRS"
Now showing 1 - 8 of 8
Results Per Page
Sort Options
Item Fecal near-infrared reflectance spectroscopy calibrations for predicting diet quality and intake of donkeys(Texas A&M University, 2006-08-16) Kidane, Negusse FessehayeThe objective of these studies was to develop near-infrared reflectance spectroscopy calibration equations from diet-fecal pair datasets to predict the diet quality and intake of donkeys. One hundred-forty diet-fecal pair samples were generated from two independent in vivo feeding trials conducted in the United States (N = 100) and Africa (N = 40). At each site, ten female donkeys were fed mixed diets blended from 25 forage and crop residues. The modified partial least square model (MPLS) was used to develop calibration equations for crude protein (CP), digestible organic matter (DOM), dry matter digestibility (DDM) and organic matter digestibility (OMD), for the US, Africa and US/Africa combined datasets, and dry matter (DM) and organic matter (OM) intake calibrations from the US datasets. Crude protein (CP) equations were developed with standard error of calibration (SEC) < 1.0 and coefficient of determination (R2) > 0.90, (SEL = 0.5). The US, US/Africa and Africa CP equations had SEC value of 0.77, 0.97 and 0.88 with corresponding R2 of 0.97, 0.95 and 0.88, respectively. Validation of the US CP equation resulted in a standard error of prediction (SEP) of 1.79 with corresponding coefficient of correlation (r2) of 0.82 and slope of 0.84 indicating high accuracy of prediction. In vivo derived DOM equations were also developed for the US, Africa and US/Africa datasets with SEC values of 2.58, 4.91 and 3.52, and R2 of 0.60, 0.81 and 0.84, respectively. In addition, the SEC and R2 values were 3.25 and 0.72 for US OMD, 3.28 and 0.79 for US DDM, and 4.2 and 0.85 for US/Africa OMD, and 4.3 and 0.87 for US/Africa DDM equation, respectively. Calibration equations for predicting DMI and OMI have resulted in SEC values of 3.45 and 3.21 (g/kgw0.75) and R2 values of 0.89 and 0.84, respectively. The present study explored the relationship between DMI and diet quality attributes. Crude protein and digestible organic matter to crude protein ration (DOM/CP) with r2 values of 0.60 and 0.39, respectively, have shown good correlations with intake. The present studies have confirmed the potential for the fecal NIRS profiling for predicting CP, DOM, DDM, OMD, DMI and OMI of donkeys. Both calibration and validation results have indicated that the present donkey equations were comparable to previously developed equations for ruminants; they have the capability for accurate prediction of diet quality and intake, and can be a useful tool for monitoring the nutritional well-being of donkeys with acceptable accuracy. Research works to further expand the present calibration equations with additional diet-fecal samples particularly from Africa that did not meet the required accuracy level is recommended.Item Genetic Analysis of Bread Making Quality Stability in Wheat using a Halberd X Len Recombinant Inbred Line Population(2012-07-16) Poudel, AshimaWheat grain quality has a complex genetic architecture heavily influenced by the growing environment. Consistency in wheat quality not only affects the efficiency of milling and baking but also the quality of end-use products. The objectives of this study were to 1) analyze the different wheat quality parameters in Recombinant Inbred Lines (RILs) grown under different environments, and 2) to identify Quantitative Trait Loci (QTLs) associated with quality stability in RILs grown under different environments. A set of 180 RILs derived from two spring wheat lines 'Halberd' and 'Len' were grown at Uvalde and College Station TX, in the 2009/2010 growing season and at Chillicothe and College Station TX, in 2010/2011 growing seasons. The experiment was laid out in Randomized Complete Block Design (RCBD) with four replications within each location. Each line was tested for multiple quality traits that included grain hardness, protein content, dough mixing properties and bread baking quality using Single Kernel Characterization System (SKCS), Near-Infrared Reflectance Spectrometry (NIRS) analysis, mixograph and the Sodium Dodecyl Sulfate Sedimentation (SDSS) test. Genetic linkage map construction was carried out with 116 single nucleotide polymorphism (SNP) markers in the RILs. Then composite interval mapping was carried out to identify QTLs associated with quality traits. The SDSS column height was positively correlated across four environments. Similarly, it was found to have significant positive correlation with mixing tolerance and peak time within and also across locations. However, the SDSS was negatively correlated with the hardness index. The protein percent was not significant with any of the quality traits within and across environments. We were able to detect many QTLs for different quality traits but most of them were site specific. Only a few QTLs were consistent across environments. Most of the QTLs for quality traits i.e., SDSS, peak time, mixing tolerance and hardness index were identified on chromosome 1B. We were able to detect overlapped QTLs for SDSS column height and mixing tolerance on chromosome 1B. Furthermore, overlapping QTLs for mixing tolerance and peak time were detected on an unknown chromosome. We also detected overlapping QTLs for hardness index on chromosome 1B. We identified one stable QTL for SDSS column height on chromosome 4B. This QTL was detected based on the coefficient of variation (CV) for SDSS in four different environments.Item The genetic architecture of quantitative traits in locally adapted plant ecotypes(2015-08) Milano, Elizabeth Rose; Juenger, Thomas; Kirkpatrick, Mark; Linder, Craig R; Lloyd, Alan; Martin, NolandLocally adapted ecotypes are a common phenomenon generating plant diversity within species, yet we know surprisingly little about the genetic mechanisms that lead to locally adapted traits. The genetic architecture underlying traits can indicate evolutionary history and predict response to selection, with applications in evolutionary ecology, conservation, and crop development. This research broadly investigates the genetic architecture of quantitative traits in paired ecotypes from different plant species. I used multivariate comparative methods and quantitative trait loci (QTL) mapping to quantify genetic correlations and population divergence, between ecologically relevant traits, both at the phenotypic and genotypic level. I tested for adaptive floral trait evolution in a perennial wildflower by comparing differentiation at neutral loci to differentiation in a suite of quantitative floral traits in an Ipomopsis aggregata hybrid zone. I used multivariate comparisons to incorporate the genetic covariance architecture underlying floral display and reward traits, and found a strong signal for divergent selection. Non-neutral divergence for multivariate quantitative traits suggests that selection by pollinators is maintaining a correlation between floral display and reward. In Panicum virgatum, a native perennial grass, I used a genetic mapping population, segregating ecotypic variation, to construct a linkage map, and map QTL for nine ecological traits. Most QTL had intermediate to small effects and clustered on a limited number of linkage groups. I also found over half of the functional allelic effects displayed patterns associated with fixed differences between ecotypes. These results suggest there is considerable standing genetic variation within local populations, as well as between ecotypes for ecologically relevant traits. Lastly, I explored the genetics of plant tissue quality in Panicum hallii, a model lignocellulosic grass system. Cell wall components compose the bulk of lignocellulosic biomass and contribute to the recalcitrance of plant tissue. I characterized the divergence of four major cell wall components between ecotypes, identified 14 QTL, and found half of the QTL localized to a single linkage group. Exploring the genetic architecture of tissue traits in a tractable system will lead to a better understanding of cell wall structure and function as well as provide genomic resources for bioenergy crop improvement.Item Impact of undesirable plant communities on the carrying capacity and livestock performance in pastoral systems of south-western Uganda(Texas A&M University, 2004-09-30) Byenkya, Gilbert StevenThe impact of undesirable plant communities (Cymbopogon afronardus and woody species dominated by Acacia species) on livestock carrying capacity and performance was investigated on 15 farms in an Acacia/Cymbopogon dominated pastoral system of south-western Uganda. Species prevalence based on basal cover for grasses, frequency for forbs and effective canopy cover for trees/shrubs were determined on farms. The PHYGROW model was used to predict forage productivity for computation of carrying capacity. The NIRS/NUTBAL nutritional management system was used to determine cattle dietary CP and DOM through fecal scans and to estimate animal performance. Cymbopogon afronardus had a prevalence of 10.29% among the grasses while Acacia gerrardii (34.37%) and Acacia hockii (33.66%) were the most prevalent woody species. Forage productivity differed significantly among the farms with a mean long-term annual forage yield of 4560(SE+41) kg/ha. Farms infested with Cymbopogon and woody species produced the least amount of forage and therefore had the lowest carrying capacities (0.38 -0.39 AU/ha) while improved farms had comparatively higher forage yields with higher carrying capacities (0.49 - 0.52 AU/ha). A mean carrying capacity for the system was estimated at 0.44 AU/ha using a 25% harvest efficiency for ANPP. All the farms were overstocked, on average by 3.2 times. Livestock BCS, diet CP and DOM were significantly different (P<0.0001) among the different farm types. BCS were highest on improved farms and lowest on Cymbopogon infested farms while dietary CP and DOM values were lowest on improved farms and highest on farms with a high woody component. Farms with a relatively high woody component exhibited intermediate BCS despite the high dietary CP values. Cattle on Cymbopogon infested farms had consistently lower body weights over the months although there were no significant differences in daily live weight gains among farms. Recommendations included need for research into appropriate control measures for both Cymbopogon afronardus and woody species, farmer sensitization about overstocking, research to improve forage quality on improved farms and need for feed supplementation for improved breeds on improved farms. Integration of NIRS/NUTBAL and PHYGROW models into the research and management systems was desirable. The observed increase in Sporobolus spp. required investigation.Item The influence of posture and muscle contraction rate on the oxygenation status of the vastus lateralis while cycling(2015-08) Hahn, Dongwoo; Coyle, Edward F., 1952-; Brothers, MathewAmong the factors that can influence the supply of blood and oxygen to the contracting skeletal muscle, the effects of posture and muscle contraction rate were investigated in this study. We hypothesized that the supine posture (SUP) would elicit less oxygenation of the vastus lateralis when cycling during moderate to intense exercise compared to upright posture (UP). In addition, we hypothesized that higher muscle contraction rate would be effective to minimize the desaturation of the vastus lateralis while cycling, and it would elicit a greater volume of oxygen uptake. A total 16 of participants were tested during upright and supine cycling at 60 RPM and 100 RPM. The four exercise intensities were calculated relative to their individual peak aerobic capacity during upright cycling. Near-infrared spectroscopy (NIRS) was applied to measure the concentrations of oxygenated hemoglobin (O₂Hb) and deoxygenated hemoglobin (HHb) of the vastus lateralis. In addition, pulmonary gas exchange (VO₂) and heart rate (HR) were measured. As a result, (HHb) was increased and % O₂ saturation was decreased as the exercise intensity increased (p<0.05). SUP elicited significantly higher (HHb) than UP (p<0.05), and less % O₂ saturation (p<0.001). A significant RPM effect was found in that 100 RPM elicited less of an increase of (HHb) comparing UP to SUP at a given moderate exercise intensity (p<0.05). Also, 100 RPM had significantly less of a drop of % O₂ saturation from UP to SUP at all exercise intensities (p<0.05). Especially at 70% of the VO₂peak, cycling in SUP 100 RPM maintained a significantly greater oxygen saturation compared to 60 RPM (p<0.05). In addition, 100 RPM elicited significantly greater volume of oxygen consumption than 60 RPM at each posture (p<0.001). In conclusion, as expected, the oxygen saturation of the skeletal muscle was significantly decreased as the exercise intensity increased. Furthermore, SUP elicited significantly less oxygen saturation of vastus lateralis than UP. Lastly, a higher muscle contraction rate can be effective in minimizing the oxygen desaturation of skeletal muscle while cycling at approximately 70% VO₂peak.Item Insights on Psittacine Nutrition through the Study of Free-living Chicks(2012-07-16) Cornejo, JuanThe Psittacidae is one of the most endangered families of birds in the world. Knowledge of its nutrition is important for understanding their survival and productivity in the wild, as well as for their adequate husbandry in captivity. Hand-rearing is a common practice for this group. However, research on their requirements is limited. Analysis of the crop content of chicks can provide new insights into psittacine nutrition, but it is limited by the small sizes of samples which can be obtained. We sampled the crops from free-living chicks of scarlet macaws and red-and-green macaws from southeastern Peru, Cuban parrots from the Bahamas, lilac-crowned parrots from northwestern Mexico, and thick-billed parrots from northern Mexico. The predicted metabolizable energy, protein, fat, minerals, profile of essential amino acids and profile of fatty acids of the crop samples, as well as from 15 commercial hand-rearing formulas, were analyzed and contrasted. Near Infrared Spectroscopy was shown to be a valid technique for the nondestructive, low cost prediction of a variety of nutritional attributes of crop samples as small as 0.5 g dry weight, expanding the possibilities of wild animal nutrition research. The diets of the five studied species presented remarkable similarities and common patterns. The predicted dietary metabolizable energy and fat concentrations were particularly similar among species, the thick-billed parrot being the one with the most unique nutrient profile. The fatty acid profile of the crop contents differed markedly among genera, with the thick-billed parrot closer to the macaws than to the parrots. In comparison with the crop samples, the hand feeding formulas presented lower fat, Mg, arginine, and valine concentrations. The wide variation in nutrients suggests that there is not yet a consensus among manufacturers concerning the correct nutrition for growing psittacines. It is suggested that a single formulation could be used to hand-rear macaws and parrots from half its nesting time to fledging, and further research should focus on their nutrition during the first half. Our results suggest that manufacturers should evaluate if increasing the concentrations of crude fat, Mg, arginine, and valine in commercial formulas enhances psittacine chick growth and health.Item Prediction of diet quality parameters of Rocky Mountain Elk via near infrared reflectance spectroscopy (NIRS) fecal profiling(Texas A&M University, 2006-08-16) Keating, Marvin ScottThe objective of this experiment was to determine the validity of predicting the diet quality of Rocky Mountain Elk (Cervus elaphus nelsoni) by exposing a dried fecal sample to light energy (a spectrophotometer). The resulting spectra measured were then compared to the known wet chemistry of the diet to arrive at an equation for forecasting the crude protein (CP) and digestible organic matter (DOM) ingested by the elk. Forages were gathered from western ranges and blended to simulate plant species ingested representing various elk diet qualities at different seasons of the year. Feeding trials were begun during the summer of 1999 using the USDA Forest Service Starkey Unit??s herd of tame elk in northeast Oregon. Additional feeding trials were conducted at Center, Texas and College Station, Texas in the spring of 2000 and the summers of 2000 and 2001, respectively. In all feeding trials, 1 elk was fed 1 diet of known quality, ad libitum, for 8 days with fecal specimens collected on day 7 and day 8 for spectral scanning. Results indicate acceptable predictability (R2 = 0.95, SEC = 1.13 for CP, R2 = 0.80, SEC=1.73 for DOM) in forecasting the diet quality of elk, and thus it is concluded that NIRS is a valuable management tool in monitoring the well-being of captive and free-ranging elk.Item Use of near infrared reflectance spectroscopy (NIRS) to investigate selection and nutrient utilization of bamboo and to monitor the physiological status of giant pandas (Ailuropoda melanoleuca)(2009-05-15) Wiedower, Erin ElizabethThe objective of this study was to develop near infrared reflectance spectroscopy (NIRS) calibration equations from bamboo and fecal samples to predict diet composition and the physiological status of giant pandas. Discrimination between branch, culm, and leaf parts of bamboo resulted in an Rsquare (R2) of 0.88. The calibration equation for discriminating between 4 species of bamboo had an R2 of 0.47. Calibration equations were created for all bamboo species combined to determine the ability of NIRS to predict the nutrient constituents of CP, NDF, ADF, DM, and OM. No R2 was lower than 0.96, with the exception of DM at 0.63, which was consistently difficult to accurately predict due to variation in factors relating to difference in location of lab work (humidity, shipping, methods, etc.). Giant panda diets vary between seasons from eating primarily leaf to eating almost only culm. When bamboo part samples were compared between March and October, all resulting R2s were above 0.80. The sensitivity analyses for leaf and culm samples within diet season produced inconclusive results, but sensitivity analyses for fecal samples yielded an ability to more greatly discriminate between months that were further apart. For giant panda physiological status calibrations, fecal samples were collected from the Memphis Zoo, Smithsonian's National Zoo, Zoo Atlanta, and San Diego Zoo from 2006 to 2007. One-hundred fecal spectra were used to develop discriminant equations with which to predict between adults and juveniles. The resulting calibration was 100% correct for both age classes. Predictions between 252 male and female fecal spectra were 89% correct for females and 90% correct for males. A small number of samples (N= 60) were used to create a discriminant equation to differentiate between pregnant and non pregnant females. The exercise resulted in an R2 of 0.68 and a prediction of 100% for both pregnant and not-pregnant. It has been determined through these studies that NIRS has the potential to determine nutrient composition of bamboo and giant panda fecals, but increased sampling and equation development is needed before these calibrations are applicable in a captive or wild giant panda setting.