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Oxidative stress contributes to inadequate in vitro maturation of porcine oocytes which leads to a failure of successful fertilization and embryo development. Therefore, the overall objective of this research was to characterize the mechanisms of oxidative stress in maturing oocytes and determine how oocytes alleviate oxidative stress with the assistance of supplemental antioxidants. A preliminary study was conducted to evaluate the effects of glutathione (GSH), N-acetyl-cysteine (NAC), and N-acetyl-cysteine-amide (NACA) supplemented to the maturation medium on intracellular GSH concentrations, nuclear maturation, fertilization success and embryo development. Antioxidants GSH, NAC and NACA (1.0 mM) were supplemented to the media during oocyte maturation. Intracellular GSH concentrations were recorded at 48 h of maturation and nuclear maturation and fertilization were analyzed 12 h after IVF. Embryo development was analyzed at 48 h and 144 h after IVF or intracytoplasmic sperm injection (ICSI). Supplementation of antioxidants had no effect on intracellular levels of GSH, nuclear maturation or fertilization traits. Blastocyst formation for NAC (35.0 ± 7.4%) and NACA (40.0 ± 7.4%) supplementation were higher (P < 0.05) than the control (20.0 ± 7.4%) and GSH supplemented (20 ± 7.4%) oocytes. The same pattern was seen for ICSI-derived embryos: blastocyst formation for NAC (22.0 ± 5.9%) and NACA (25.0 ± 4.6%) supplementation were higher (P < 0.05) than the un-supplemented (10.0 ± 6.0%) oocytes. There were no differences between NAC and NACA supplementation and there were no differences between the cleavage rates for any of the treatment groups. These results indicate that supplementing 1.0 mM of NAC or NACA to the oocyte maturation medium and the ICSI medium increased the percentage of viable embryos reaching the blastocyst stage of development, and could warrant further investigation. The next study was conducted to evaluate the effects of different concentrations of NAC supplemented to the maturation medium on embryo development. Comparisons of significant concentrations of NAC and NACA on embryo development were evaluated for nuclear maturation, fertilization success and embryo development. Concentrations of NAC (0, 0.5, 1.0, 1.5, 2.0, 2.5, 5.0 mM) were supplemented to maturing oocytes and embryo development was analyzed at 48 h and 144 h post-fertilization. There were no differences between cleavage rates for any of the treatment groups. Blastocyst formation for 1.5 mM NAC (56.5 ± 9.2%) was significantly higher (P < 0.05) than all other supplementations. There were no differences in nuclear maturation or fertilization when comparing 1.5 mM NAC and 1.5 mM NACA supplementation to the maturation media. There was no difference between cleavage rates of 1.5 NAC and 1.5 mM NACA supplementation to the maturation media. Blastocyst formation for 1.5 mM NAC (44.4 ± 4.7%) and 1.5 mM NACA (46.2 ± 3.4%) supplementation were significantly higher (P < 0.05) than the control (32.1 ± 6.2%) oocytes. These results indicate that supplementing 1.5 mM of NAC or NACA to the oocyte maturation medium increased the percentage of viable embryos reaching the blastocyst stage of development and could be used during the oxidative stress experiments. In the final study, the mechanisms of oxidative stress in maturing oocytes were studied in addition to evaluating the effects of antioxidant supplementation to the media. This study focused on superoxide dismutase (SOD), GSH peroxidase, catalase and intracellular GSH concentrations with respect to DNA fragmentation evaluated using the single cell Comet assay. Results indicate that when SOD was inhibited, the GSH peroxide levels and length of DNA migration significantly increased (P < 0.05). Catalase levels significantly decreased (P < 0.05) and intracellular GSH remained unchanged. When GSH peroxidase was inhibited, the SOD levels and catalase levels significantly decreased (P < 0.05) but the intracellular GSH and DNA migration length significantly increased (P < 0.05). The supplementation of 1.5 mM NAC and 1.5 mM NACA had multiple effects on the enzyme levels. Specifically, supplementation of 1.5 mM NAC or 1.5 mM NACA significantly decreased (P < 0.05) the length of DNA migration when other enzymes were inhibited compared to no antioxidant supplementation. These results indicate that antioxidant supplementation may alleviate the free radicals associated with oxidative stress in the maturing porcine oocyte. In conclusion, supplementing the antioxidants NAC or NACA to the oocyte maturation media does not have negative effects on IVF or embryo culture. Supplementation of NACA increases the number of oocytes reaching the blastocyst stage of development. Glutathione, SOD, catalase, and GSH peroxidase are all required to be functional during oocyte development to alleviate oxidative stress on the oocyte. Antioxidants enhance the enzyme activity during oocyte maturation and may even contribute to protecting the oocyte when enzyme activity is impaired. / Ph. D.

The petroleum industry faces problems in transportation of crude petroleum be- cause of the deposition of paraffins, hydrates and asphaltenes on the insides of the pipeline. These are conventionally removed using either chemical inhibitors or mechani- cal devices, called pigs, which travel through the pipeline and mechanically scrape away the deposits. These pigs are propelled by the pipeline product itself and hence travel at the same velocity as the product. Research has indicated that cleaning would be better if the pigs are traveling at a relatively constant velocity of around 70% of the product velocity. This research utilizes the concept of regulating the bypass flow velocity in order to maintain the pig velocity. The bypass flow is regulated by the control unit based on the feedback from the turbine flowmeter, which monitors the bypass flow. A motorized butterfly valve is used for actually controlling the bypass flow. In addition to cleaning, the proposed pig utilizes on-board electronics like accelerom- eter and pressure transducers to store the data gathered during the pig run. This data can then be analyzed and the condition of the pipeline predicted. Thus, this research addresses the problem of designing a pig to maintain a constant velocity in order to achieve better cleaning. It also helps gather elementary data that can be used to predict the internal conditions in the pipe.

The aim of this thesis was to evaluate the pig fattening at the school farm in Měšice. The work is concern with the evaluation of the fattening period, the production and realization price of the pigs. The monitoring was conducted from 2010 to 2011. The evaluation included a total of 1994 pigs. The thesis take into consideration not only the initial and final weight of the animals, the losses, duration of the fattening period and the average slaughter weight, but also the total costs of their fattening. The statistical analysis was performed using Microsoft Excel. To evaluate the results the monitored indicators were calculated as average values and differences between data. When taken into the pre?fattening in 2010 the average weight reached 5.10 kg per piglet. In 2011 this figure dropped to 5.05 kg. The average weight of pigs sold in 2010 was 107.35 kg. It declined in 2011 to 101.27 kg. In 2010 the school farm in Měšice achieved an average daily weight gain of 0.67 kg. This number increased in 2011 to 0.74 kg. The average fattening cost per pig/day, during the reporting period in 2010, was 26.07 CZK. There was an increase the following year by 0.89 CZK to the amount of 26.96 CZK. When selling the pork meat in 2010, the average realized price by the farm was 26.46 CZK/kg. In 2011, the average realized price rose by 2.35 CZK / kg, thus increased to CZK 28.81CZK/kg Considering all the indicators and the production costs of the pig meat, the farm encountered a loss for the entire reporting period.

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Doctor of Philosophy / Department of Diagnostic Medicine/Pathobiology / Steven S. Dritz / A total of 8 experiments and a meta-analysis were performed with the overarching goal to improve amino acid and energy utilization in swine diets. The first experiment used a total of 255 nursery pigs to evaluate the optimum dietary standardized ileal digestible (SID) tryptophan to lysine (Trp:Lys) ratio. Four experiments also were conducted using 6,668 finishing pigs to determine the effects of SID Trp:Lys ratio in diets containing dried distillers grains with solubles (DDGS) on growth performance and carcass characteristics. A subsequent experiment evaluated the interaction between Trp and large neutral amino acids (Trp:LNAA) on growth performance of early and late-finishing pigs. Lastly, data from 41 trials and 2 validation trials were used to develop a regression equations to predict ADG or gain to feed (G:F) as influenced by BW and net energy (NE) content in growing-finishing pigs. In Exp. 1, the growth performance and economics indicated the optimum SID Trp concentration for 6-to 10-kg nursery pigs at 20.3% of Lys. In Exp. 2, 3, and 4, there were no differences in growth performance due to SID Trp:Lys ratio; however, increasing the SID Trp:Lys ratio suggested an opportunity to improve carcass yield and lean in pigs fed high levels of DDGS. Experiment 5 indicated an optimum SID Trp:Lys ratio of 20% for 71- to 127-kg pigs fed high level of DDGS. In Exp. 6, growth performance was unaffected by dietary treatment suggesting that 16.5% SID Trp:Lys was adequate to prevent a negative impact on growth when SID Trp:LNAA was as low as 3.0% in finishing period. Overall, the experiments suggested a higher optimum SID Trp:Lys ratio than is currently standard practice. The regression analysis from the meta-analysis showed that increasing dietary NE improved ADG and G:F. However, the magnitude of improvement will be minimized if the SID Lys concentration is limiting. The validation experiments indicated that the prediction equations provided a good estimation of growth rate and feed efficiency of growing-finishing pigs fed different levels of dietary NE except for pigs fed the diet with DDGS. These predictions of growth performance can then be used to model economic value of different dietary energy strategies.