Abstract   The aim of this study was to increase knowledge of how plants as a whole respond to targeted fertilization and to refine the method of foliar nutrition fertilization. The experiment also aimed to test how herbivores respond when presented with a choice between fertilized and unfertilized Salix leaves in a feeding trial experiment. One major problem that arises when trying to alter the nutrient levels within a specific part of a plant is that adding fertilizer directly to the soil in which the plants grow will have a systemic effect on the plant, causing the plant physiology as a whole to change instead of just changing the properties of the plant part which the study focuses on. The approach chosen for this experiment is to target the leaves directly when applying the fertilizer and therefore try to avoid altering the rest of the plant. Fertilizer in the form of NH3NO4 was added to Salix leaves using a pipette and a brush at two different concentrations. When the leaves had been fertilized they were analyzed and used in a feeding trial experiment to study herbivore response to targeted fertilization. Once all data was analyzed statistically it became clear that both concentrations of the treatment had altered the nitrogen content within the leaves, however only the lower concentration had done so without altering the characteristics of the leaf. The data collected from the feeding trial displayed no statistical evidence for preference between the treated and control leaves in regard to amount consumed by the Phratora beetles, on the other hand when testing for egg laying preference 8/8 of egg clutches were laid on treated leaves.

ABSTRACT SALT DRIVE IN THE BEAVER (Castor canadensis): AN EXPERIMENTAL ASSESSMENT WITH FIELD FEEDING TRIALS SEPTEMBER 2012 JENNIFER E. STRULES, B.M. BERKLEE COLLEGE OF MUSIC M.S., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Stephen DeStefano Salt drive is a seasonal phenomenon common to several classes of wild herbivores. Coincident with shifts of nutrient quality when plants resume growth in the spring, sodium is secondarily lost as surplus potassium is excreted. The beaver (Castor canadensis) is an herbivore whose dietary niche closely follows that of other herbivores that are subject to salt drive, but no published studies to date have assessed the likelihood of its occurrence. To quantify if beavers experience seasonal salt drive, we designed a field experiment to measure the foraging responses of beavers to sodium-enhanced foods. We used sodium-treated (salted) and control food items (aspen [Populus tremuloides] and pine [Pinus spp.] sticks) during monthly feeding trials at beaver-occupied wetlands where water lily (Nymphaea spp. and Nuphar spp.) was present and where water lily was absent. If conventional ontogeny of salt drive was operant, we expected to observe greater utility of sodium-treated food items by beavers in May and June. Further, if water lilies supplied beavers with sodium to meet dietary requirements as is widely speculated, we expected foraging responses to sodium-treated food items at wetlands where water lilies were absent to be greater than at wetlands where water lily was present. Aspen was selected by beavers in significantly greater amounts than pine. There was no difference between the mean percent consumed of salted and control aspen sticks by beavers at lily and non-lily wetlands, and no differences in temporal consumption associated with salted or control pine sticks at either wetland type. Salted pine was consumed in greater amounts than unsalted pine. We propose that the gastrointestinal or renal physiology of beavers may predispose them to low solute loss, thereby preventing salt drive.

The objective was to conduct a systematic review and meta-analysis of randomized feeding trials to assess the effect of dietary pulses (beans, chickpeas, lentils, peas) on established lipid targets of cardiovascular disease (CVD) and perform a secondary analysis of our randomized feeding trial to assess whether dietary pulses as a means of lowering the glycemic index offer further CVD protection by reducing oxidative stress. The meta-analysis of 26 trials (n=1013) found dietary pulse interventions significantly lowered LDL-C compared with isocaloric control interventions (mean difference=-0.17mmol/L [95% CI: -0.25, -0.09]; p<0.0001). No treatment effects were observed for Apo-B and non-HDL-C. Our feeding trial found no significant differences between the high-dietary pulse diet and high-fibre control diet on markers of oxidative stress, including thiobarbituric acid reactive substances (TBARS), conjugated dienes (CDs), and protein thiols. Overall, the results suggest dietary pulses reduce LDL-C but not oxidative stress as a means of reducing cardiovascular risk.

The objective was to conduct a systematic review and meta-analysis of randomized feeding trials to assess the effect of dietary pulses (beans, chickpeas, lentils, peas) on established lipid targets of cardiovascular disease (CVD) and perform a secondary analysis of our randomized feeding trial to assess whether dietary pulses as a means of lowering the glycemic index offer further CVD protection by reducing oxidative stress. The meta-analysis of 26 trials (n=1013) found dietary pulse interventions significantly lowered LDL-C compared with isocaloric control interventions (mean difference=-0.17mmol/L [95% CI: -0.25, -0.09]; p<0.0001). No treatment effects were observed for Apo-B and non-HDL-C. Our feeding trial found no significant differences between the high-dietary pulse diet and high-fibre control diet on markers of oxidative stress, including thiobarbituric acid reactive substances (TBARS), conjugated dienes (CDs), and protein thiols. Overall, the results suggest dietary pulses reduce LDL-C but not oxidative stress as a means of reducing cardiovascular risk.

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There has been increased interest in utilizing switchgrass (Panicum virgatum) as biomass. There are several challenges to developing this industry, and these have led to the potential use of switchgrass as hay for feeding beef cattle in Kentucky. The effect of increasing maturity on crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and nutritive values of switchgrass hay has been well documented, but few in vivo intake and digestibility trials have been conducted to assess this effect on animal performance when feeding beef cattle. Two in vivo intake and digestibility trials were conducted in 2011 in which Angus x Hereford beef steers (200-265 kg) were fed Alamo and Cave-in-Rock switchgrass harvested as late vegetative, boot, and early flowering hay. The objectives of these trials was to evaluate the effect of increasing maturity on apparent dry matter intake (DMI), digestible dry matter intake (DDMI), and dry matter digestibility (DMD); and to discuss potential challenges that producers might face if incorporating switchgrass hay into their forage program for feeding beef cattle. Observed decreases in nutritive value, DMI, DDMI, and DMD indicate that producers should harvest Alamo and Cave-in-Rock switchgrass before it reaches the boot stage of maturity.