Three experiments were conducted to determine the nutritive value of black Brassica napus (BBN), yellow Brassica juncea (YBJ) and yellow Brassica napus (YBN) in pig diets. In experiment 1, effect of multi-carbohydrase supplementation on SID of AA in BBN, YBJ and YBN was evaluated in growing pigs. The YBJ had similar SID of AA to BBN and enzyme did not affect SID of most of AA. The second and third experiments investigated the effect of high dietary inclusion of BBN and YBJ on weaned pig performance and nutrient digestibility with enzyme supplementation. The studies showed that weaned pigs can be fed diets containing up to 250 g/kg of either BBN or YBJ. Enzyme supplementation improved the nutrient digestibility. In conclusion, BBN and YBJ had similar digestible nutrient contents and there were no detrimental effects detected when pigs were fed up to 250 g/kg of BBN and YBJ in weaned pigs.

Management of clubroot caused by the soil-borne biotrophic plant protist Plasmodiophora brassicae on canola and other Brassica crops is an important challenge to producers. Studies on the interaction of pH and temperature on root hair infection (RHI) and clubroot symptom development in canola roots revealed that high levels of clubroot can occur under optimum temperature, moisture and spore load, even at alkaline pH of 7.5. Clubroot was suppressed at all temperatures at pH 8.0, but not totally eliminated. The occurrence of maximum levels of root hair infection and clubroot development (RHI = 61%, Clubroot incidence (CI) & Disease severity index (DSI) = 100%) at temperatures of 20° and 25°C and pH of 5.0 to 6.5 was confirmed. The efficacy of biofungicides against P. brassicae was influenced by pathogen load, host, growth media and its properties. Drench application of Serenade and Prestop were moderately effective in reducing clubroot levels in canola (Brassica napus L. and B. rapa L.) and to a lesser extent in Shanghai pak choy (B. rapa L. ssp. Chinensis (Rupr.) var. communis Tsen and Lee). The mean clubroot incidence and severity caused by Pathotype 3 was found to be slightly higher than that of Pathotype 6. Clubroot level increased with increase in soil bulk density.

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Three experiments were conducted to determine the nutritive value of black Brassica napus (BBN), yellow Brassica juncea (YBJ) and yellow Brassica napus (YBN) in pig diets. In experiment 1, effect of multi-carbohydrase supplementation on SID of AA in BBN, YBJ and YBN was evaluated in growing pigs. The YBJ had similar SID of AA to BBN and enzyme did not affect SID of most of AA. The second and third experiments investigated the effect of high dietary inclusion of BBN and YBJ on weaned pig performance and nutrient digestibility with enzyme supplementation. The studies showed that weaned pigs can be fed diets containing up to 250 g/kg of either BBN or YBJ. Enzyme supplementation improved the nutrient digestibility. In conclusion, BBN and YBJ had similar digestible nutrient contents and there were no detrimental effects detected when pigs were fed up to 250 g/kg of BBN and YBJ in weaned pigs.

Reducing consumption of fat is recommended for obese individuals; however, altering dietary fat, without reducing total fat, may modify obesity-associated consequences. The effects of dietary fat composition on obesity and insulin resistance in diet-induced obese rats were investigated. Rats were fed a high-fat lard-based diet for 12 weeks and then were randomized into one of six high-fat treatment groups (oils used: high-oleic canola, conventional canola, high-oleic/conventional canola mix, conventional canola/flax mix, safflower, or soybean) or kept on the lard diet for 8 weeks. Diets had varying effects on lipidemia and glycemia; however, insulin tolerance tests, oral glucose tolerance tests, and the skeletal muscle response to insulin were not different among groups. Muscle phospholipids showed expected differences in fatty acid (FA) composition, but polyunsaturated/saturated FA ratios were not different among groups. Overall, a consistent response to high-fat diets was observed which may be attributed to the robustness of polyunsaturated/saturated FA ratios of muscle phospholipids.

Considerable interest has focused on the influence of dietary fat quality on cardiovascular disease (CVD) risk. Increasingly, novel dietary oils rich in oleic acid and alpha-linolenic acid (ALA) are being developed and marketed with an aim to improve fatty acid intakes and reduce CVD risk. The objective of this research was to investigate the efficacy of high-oleic canola oil (HOCO) alone, or blended with flaxseed oil (FXCO), on traditional and emerging clinical biomarkers of CVD risk. An additional aim was to study the influence of dietary and genetic factors on metabolism of 13C-ALA to long-chain PUFA. Using a diet-controlled randomized crossover design, thirty-six hypercholesterolaemic subjects consumed three isoenergetic diets for 28 days each containing ~36% energy from fat, of which 70% was provided by HOCO, FXCO, or a Western dietary fat blend (WD; control). Endpoint measures revealed reductions (P<0.001) in serum lipid concentrations, including a 7.4% and 15.1% decrease in LDL-cholesterol after HOCO and FXCO diets, respectively, as compared with the WD control. Moreover, a reduction (P=0.023) in plasma E-selectin concentration was found after the FXCO diet compared with the WD control. Consumption of the dietary oils failed to alter whole-body fat oxidation or energy expenditure, nor lead to alterations in body composition. FXCO diet increased (P<0.001) plasma ALA ~5-fold, EPA ~3-fold, and DPA ~1.5-fold, but did not modulate DHA levels compared with the WD control. At 24 and 48 hours the amount of administered 13C-ALA recovered as plasma 13C-EPA and 13C-DPA was lower (P<0.001) after FXCO diet compared with HOCO and WD diets, suggesting decreased ALA conversion efficiency with very high intakes of dietary ALA. No difference in plasma 13C-DHA enrichment was observed across diets. Moreover, minor alleles of selected single nucleotide polymorphisms in the FADS1/FADS2 gene cluster were associated with reduced (P<0.05) plasma fatty acid compositions and apparent conversion of 13C-ALA. However, increased consumption of ALA in the FXCO diet compensated for lower levels of EPA in minor allele homozygotes. Taken together, substitution of dietary fats common to WD with both HOCO and FXCO represents an effective strategy to target several biomarkers for CVD risk reduction.

Optimization of the culture conditions for the biomass production of the alga Phaeodactylum tricornutum was investigated in relation to chlorophyllase activity. To obtain the highest total chlorophyllase activity, the biomass of P. tricornutum was harvested after a period of 7 days of incubation during which the incubation temperature was maintained at 18°C for 18 h during the day and 10°C for 6 h during the night. During culture incubation, illumination was provided by fluorescent lamps projecting an incident intensity of 330 mumol/m2.s and the pH of the culture was maintained at 8.4, adjusted by a stream flow of CO 2. The hydrolytic activity of a partially purified chlorophyllase extract, obtained from the fresh biomass of P. tricornutum, was investigated in an aqueous/miscible organic solvent system containing refined bleached deodorized (RBD) canola oil, and chlorophyll or pheophytin as substrate. The effect of a wide range of oil contents, chlorophyll and pheophytin concentrations, acetone concentrations, incubation temperatures and agitation speeds on the enzyme activity was studied. The optimum reaction conditions for chlorophyllase biocatalysis were determined to consist of 20% oil, 10% acetone and a 200 rpm agitation speed with optimum temperatures and substrate concentrations of 35°C and 12.6 muM for chlorophyll, and 30°C and 9.3 muM for pheophytin. The presence of RBD canola oil showed an inhibitory effect on chlorophyllase activity whereas acetone acted as an activator at low concentrations and an inhibitor at higher ones. Moreover, chlorophyllase showed a limited affinity towards pheophytin as substrate compared to that obtained for chlorophyll. Selected samples of crude commercial canola oil were analyzed for their green pigment content using high-performance liquid chromatography and chlorophyllase biocatalysis was investigated on eight varieties of crude commercial canola oil. The chlorophyllase activity was lower in th

Canola protein isolate (CPI) has tremendous potential as a protein alternative to soy within the global protein ingredient market. The overall goal of this thesis was to compare and contrast the gelling mechanism of CPI with a commercial soy protein isolate (SPI) ingredient. Specifically, the gelation properties of CPI and SPI were evaluated as a function of protein concentration (5.0–9.0%), destabilizing agent [0.1 – 5.0 M urea; 0.1 and 1.0% 2-mercaptoethanol], ionic strength (0.1, 0.5 M NaCl) and pH (3.0, 5.0, 7.0, 9.0). The fractal properties of CPI were evaluated as a function of protein concentration (5.0 – 9.0%) and pH (3.0, 5.0, 7.0, 9.0). In the first study, the gelling properties of CPI and SPI as a function of concentration were evaluated, along with the nature of the interactions within their respective gel networks. Overall, the magnitude of the storage modulus (G') of the gel was found to increase with increasing concentration at pH 7.0, whereas the gelling temperature (Tgel) remained constant at ~88ºC. As the NaCl level was increased from 0.1 to 0.5 M, the zeta potential was found to be reduced from ~-20 to -4 mV, but with little effect on Tgel or network strength. In the presence of 2-mercaptoethanol, networks became weaker, indicating the importance of disulfide bridging within the CPI network. Disulfide bridging, electrostatics and hydrogen bonding are all thought to have a role in CPI gelation. In the case of SPI, the magnitude of the storage modulus (G') and Tgel were found to increase and decrease (~80ºC to 73ºC), respectively, with increasing urea concentration at pH 7.0. Increases in NaCl from 0.1 to 0.5 M reduced the zeta potential from ~-44 to -13 mV and caused a shift in Tgel from ~84ºC to 67ºC, and increased G'. No gels were formed in the presence of 2-mercaptoethanol. In the second study, the effect of pH on the gelling properties of CPI and SPI was evaluated. Surface charge (i.e., zeta potential) measurements as a function of pH found CPI to be positively (+18.6 mV), neutral and negatively (-32 mV) charged at pH 3.0, ~5.6 and 9.0, respectively. On the other hand, SPI was observed to be positively (+35.4 mV), neutral and negatively (-51 mV) charged at pH 3.0, 5.0 and 9.0, respectively. An increases in NaCl concentration from 0 M to 0.1 M resulted in a reduction in surface charge at all pHs for both CPI and SPI. Differential scanning calorimetry was performed to determine the thermal properties of CPI. The gelation temperature was found to be above the onset temperature for denaturation. For CPI, the onset of denaturation was found to occur at ~68ºC and then increased to ~78-79ºC at pH 7.0-9.0. With respect to rheological properties, SPI did not gel at pH 9.0, and G' declined as pH increased from 3.0 to 7.0. CPI did not gel at pH 3.0, however the network formed at pH 5.0 became stronger (higher G') as pH increased. The SPI gelling temperature at pH 3.0, 5.0 and 7.0 was observed to be ~85.6, ~46 and ~81ºC, respectively. SPI gels formed at pH 5.0 earlier due to increased protein aggregation near its isoelectric point (pI). The gelation temperature for CPI at pH 5.0 and 7.0 were similar (~88ºC), then declined at pH 9.0 (~82ºC). Network structure of CPI as a function of pH also was investigated using confocal scanning light microscopy (CSLM). As the pH became more alkaline from pH 7.0 to pH 9.0, there was a decrease in lacunarity (~0.41->~0.25). However, the fractal dimension was found to increase (from ~1.54 to ~1.82) showing that increasing the pH resulted in a more compacted CPI network. In summary, protein-protein aggregation induced either by increasing concentration or changing the pH resulted in network formation for both CPI and SPI, where both networks were thought to be stabilized by disulfide bridging and hydrogen bonding. SPI underwent protein aggregation earlier than CPI near its pI value, whereas CPI gels formed the strongest networks away from its pI under alkaline conditions. In all cases, CPI grew in diffusion-limited cluster-cluster aggregation to from the gel network.

Pseudomonas chlororaphis PA23 inhibits several root pathogens in both the greenhouse and field. A LysR-type transcriptional regulator (LTTR) called PtrA (Pseudomonas transcriptional regulator A) that is essential for Sclerotinia sclerotiorum antifungal activity was discovered through transposon mutagenesis. P. chlororaphis PA23 produces the antibiotics phenazine 1-carboxylic acid, 2-hydroxyphenazine and pyrrolnitrin, and several additional products that contribute to biocontrol. Phenotypic assays and proteomic analysis have revealed that production of these secondary metabolites are markedly reduced in a ptrA mutant. Most LTTRs regulate genes that are upstream of and divergently transcribed from the LTTR locus. A short chain dehydrogenase (scd) gene lies immediately upstream of ptrA in the opposite orientation. Characterization of an scd mutant, however, has revealed no significant changes in antifungal activity compared to wild-type PA23. Gene expression analysis of the ptrA mutant indicates that ptrA may exert its regulatory effects through the Gac-Rsm network, and may be controlling expression of the scd gene. Collectively these findings indicate that PtrA is an essential regulator of PA23 biocontrol and is connected to other regulators involved in fungal antagonism.