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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Metabolic and genetic regulation in adipose tissue of Angus and Wagyu steers raised to U.S. and Japanese endpoints

Chung, Ki Yong 16 August 2006 (has links)
We hypothesized that carcass and fatty acid composition of Angus and Japanese Black (Wagyu) steers would not differ if the steers were fed to a typical U.S. final weight, but that Wagyu steers fed to a typical Japanese endpoint body weight would have greater quality grades and softer fat than Angus steers. Sixteen Angus and 16 Wagyu 8-month-old, weaned steers were assigned to a corn-based diet for 8 or 16 months (n = 4 per breed type and time) or hay-based diet for 12 or 20 months (n = 4 per breed type and time) in a 2 x 2 x 2 factorial arrangement. USDA yield grade was greater at the Japanese endpoint than at the U.S. endpoint in Angus steers (breed x endpoint, P = 0.03). Intramuscular (i.m.) lipid continued to increase to over 20% in the Wagyu steers (P = 0.05), but attained a plateau (14.7%) by 16 months on feed in the Angus steers. These results confirm that Wagyu cattle must be raised to greater physiological maturity before they differ from Angus cattle in M. longissimus thoracis i.m. lipid concentration. Subcutaneous adipose tissue concentrations of oleic (18:1n-9) was greater in Wagyu steers than in Angus steers (P = 0.05). All monounsaturated fatty acids (MUFA) increased between the U.S. and Japanese endpoint, whereas slip points of lipids in s.c. adipose tissue were 10°C lower in Japanese endpoint steers than in U.S. endpoint steers (P = 0.01). Angus adipose tissue exhibited peak SCD enzyme activity at 16 months (corn-based diet) but activity in Wagyu adipose tissue was greatest at 20 months (hay-based diet) (breed x diet x endpoint, P = 0.08). However, SCD gene expression in Angus adipose tissue was maximal at 12 months (hay diet), whereas Wagyu adipose tissue had peak expression at 16 months (corn diet) (P < 0.03). Trans-10, cis-12 CLA has been reported as a potent inhibitor of adipocyte differentiation. CLA (40 µM) strongly decreased SCD and PPARγ expression in bovine adipocytes, even in the presence of 5 mM arginine. It can be concluded that arginine up-regulates bovine preadipocyte differentiation, and CLA antagonizes this effect.
2

Metabolic and genetic regulation in adipose tissue of Angus and Wagyu steers raised to U.S. and Japanese endpoints

Chung, Ki Yong 16 August 2006 (has links)
We hypothesized that carcass and fatty acid composition of Angus and Japanese Black (Wagyu) steers would not differ if the steers were fed to a typical U.S. final weight, but that Wagyu steers fed to a typical Japanese endpoint body weight would have greater quality grades and softer fat than Angus steers. Sixteen Angus and 16 Wagyu 8-month-old, weaned steers were assigned to a corn-based diet for 8 or 16 months (n = 4 per breed type and time) or hay-based diet for 12 or 20 months (n = 4 per breed type and time) in a 2 x 2 x 2 factorial arrangement. USDA yield grade was greater at the Japanese endpoint than at the U.S. endpoint in Angus steers (breed x endpoint, P = 0.03). Intramuscular (i.m.) lipid continued to increase to over 20% in the Wagyu steers (P = 0.05), but attained a plateau (14.7%) by 16 months on feed in the Angus steers. These results confirm that Wagyu cattle must be raised to greater physiological maturity before they differ from Angus cattle in M. longissimus thoracis i.m. lipid concentration. Subcutaneous adipose tissue concentrations of oleic (18:1n-9) was greater in Wagyu steers than in Angus steers (P = 0.05). All monounsaturated fatty acids (MUFA) increased between the U.S. and Japanese endpoint, whereas slip points of lipids in s.c. adipose tissue were 10°C lower in Japanese endpoint steers than in U.S. endpoint steers (P = 0.01). Angus adipose tissue exhibited peak SCD enzyme activity at 16 months (corn-based diet) but activity in Wagyu adipose tissue was greatest at 20 months (hay-based diet) (breed x diet x endpoint, P = 0.08). However, SCD gene expression in Angus adipose tissue was maximal at 12 months (hay diet), whereas Wagyu adipose tissue had peak expression at 16 months (corn diet) (P < 0.03). Trans-10, cis-12 CLA has been reported as a potent inhibitor of adipocyte differentiation. CLA (40 µM) strongly decreased SCD and PPAR&#947; expression in bovine adipocytes, even in the presence of 5 mM arginine. It can be concluded that arginine up-regulates bovine preadipocyte differentiation, and CLA antagonizes this effect.
3

High-Oleic Ground Beef and Risk Factors for Cardiovascular Disease in Men and Postmenopausal Women

Ghahramany, Ghazal 2012 May 1900 (has links)
About half of all deaths in developed countries are caused by cardiovascular disease. It is well known that cardiovascular disease (CVD) risk can be influenced by diet, but optimal dietary content of fatty acids continues to be debated. The effect of fatty acid composition of ground beef on selected cardiovascular disease risk indicators was evaluated with two primary goals. The first goal was to document effects of ground beef fatty acid composition on plasma lipoprotein concentrations, whereas the second goal was to determine the effects of ground beef fatty acid composition on gene expression in peripheral blood mononuclear cells (PBMC). In both studies the results were compared between men and women. Twelve men and women over age of 45 out of initially 15 completed a two-way crossover design. Subjects consumed five, 114-g ground beef patties per week for 5-wk periods separated by a 3-wk washout period. Patties contained on average 20% fat and monounsaturated fatty acid (MUFA): saturated fatty acid (SFA) of 0.8 and 1.1 for low- MUFA (conventional) ground beef high-MUFA (premium) ground beef patties, respectively. Blood was collected from each subject before and at the end of each diet period. Overall, the ground beef interventions decreased total plasma cholesterol, triacylglycerol, and very low density lipoprotein (VLDL) cholesterol. Plasma concentrations of high density lipoprotein (HDL) cholesterol and low density lipoprotein (LDL) cholesterol decreased and increased, respectively with premium ground beef consumption. The change in HDL cholesterol was significant in women but not in men suggesting that premium ground beef consumption had a greater impact on women than in men. For the second goal PBMC were isolated and the expression of selected genes was quantified by real-time PCR. ATP-binding cassette A1, ATP-binding cassette G1, and low-density lipoprotein receptor relative expression was increased with premium ground beef consumption. A significant increase was seen in stearoyl-Coenzyme-A desaturase 1 expression after premium ground beef treatment. With the exception of stearoyl-Coenzyme-A desaturase 1, all these genes were down-regulated with conventional ground beef consumption. Both sterol regulatory element binding transcription factor 1 and mediator complex subunit 1 were down-regulated after each beef patty treatment, but the effect was significant after consuming conventional ground beef. This suggests that genes involved in cholesterol metabolism were down-regulated with conventional ground beef consumption; whereas genes related to lipogenesis were up-regulated with premium ground beef consumption. From these data we concluded that different ground beef dietary interventions have different impacts on the PBMC gene expression that is related to cholesterol metabolism, inflammation and liver X receptor pathways.
4

Vliv přídavku oleje do krmiva modelového organismu na zastoupení mastných kyselin ve vybraných tkáních

Kaňoková, Linda January 2019 (has links)
The Master's thesis deals with the effect of feed enrichment with various types of oils on the deposition of fatty acids in selected tissues. Forty male Wistar Albino rats were divided into four groups and fed for 10 weeks daily ad libitum with a basic feed mixture enriched with 8 % palm, 8 % safflower, 8 % fish oil or 8 % microalgae Schizochytrium sp. oil. Rats had also free access to the drinking water. Fat from the tissue samples (liver, muscle, visceral fat) was extracted, converted to methyl esters and analyzed with usage of gas chromatography. The results of the experiment show that the addition of various types of oils to the feed of model organism can influence the deposition of fatty acids in its tissues. The addition of fish oil and microalgae Schizochytrium sp. oil caused statistically significant decrease (p < 0,05) in the ratio of PUFA n-6/n-3 in all observed tissues to a value of 1 or less compared to the addition of palm and safflower oil. Low ratio of n-6/n-3 polyunsaturated fatty acids is considered to be more desirable in reducing the risk of cardiovascular diseases.
5

Effect of consuming ground beef of differing monounsaturated fatty acid content on atherosclerotic cardiovascular disease risk factors in healthy men

Cao, Xiaojuan 15 May 2009 (has links)
Atherosclerotic cardiovascular disease (ASCVD) is currently the most common cause of death in the United States. Some dietary factors contribute importantly to ASCVD and other factors can reduce risk of ASCVD. Oleic acid is a monounsaturated fatty acid (MUFA). Dietary patterns in which oleic acid contributes to a majority of dietary fatty acids are associated with reduced ASCVD risk. These beneficial effects are due to MUFA-induced lipoprotein profile changes such as decreases in low density lipoprotein (LDL) and increases in high density lipoprotein (HDL). LDL oxidation plays a central role in atherosclerosis development as it both initiates and propagates atherosclerosis. HDL is anti-atherogenic as it can attenuate LDL oxidation. HDLs are a class of diverse lipoprotein that varies in protein and enzymatic composition. The paraoxonase (PON) family of enzymes, especially PON1, is primarily expressed in the liver; PON activity in the circulatory system is associated with HDL. Both PON and HDL have been documented to be anti-atherogenic. Other factors such as homocysteine and C-reactive protein (CRP) can also be considered risk factors for ASCVD. However, studies of risk factors in healthy men who consume ground beef with a different content of MUFA are lacking; hence, no conclusive evidence has established whether consuming a high amount of MUFA in the form of ground beef alters the development of atherosclerosis. The overall purpose of this study was to investigate whether the provision of ground beef with a fractionally higher MUFA content could lower or improve several ASCVD risk factors in men who consume ground beef. These risk factors include the metabolic indices of glucose, insulin and homeostasis model assessment (HOMA), inflammation risk factors of CRP and homocysteine and anti-risk factor of paraoxonase. The concentration of homocysteine was determined spectrophotometrically following separation by high pressure liquid chromatography (HPLC). Enzyme-linked imminosorbent assay kits that measured the CRP and insulin concentration in plasma. The significance of the results was determined by subjecting the data to ANOVA using the general linear model for repeated measurement (P<0.05). From this study, it can be concluded that MUFA has a beneficial effect of lowering risks as determined by metabolic indices and lipoprotein profile. Moreover, our study showed that different concentrations of MUFA in ground beef has no effect on PON1 activity, but that increased beef consumption generally reduces PON1 in association with increases in homocysteine concentration while improving indicators of glucose tolerance.
6

ALTERNATIVE FEEDING STRATEGIES TO MAXIMIZE MARINE FEEDSTUFF REPLACEMENT IN LARGEMOUTH BASS Micropterus salmoides CULTURE WHILE MAINTAINING PRODUCTION PERFORMANCE

Coursey, Andrew Richard 01 August 2011 (has links)
ANDREW R. COURSEY, for the Master of Science degree in Zoology, presented 24 June 2011 at Southern Illinois University Carbondale TITLE: ALTERNATIVE FEEDING STRATEGIES TO MAXIMIZE MARINE FEEDSTUFF REPLACEMENT IN LARGEMOUTH BASS Micropterus salmoides CULTURE WHILE MAINTAINING PRODUCTION PERFORMANCE Advisors: Chris Kohler and Jesse Trushenski Harvest of marine resources for feedstuff production is at its maximum sustainable yield and alternative feedstuffs are needed to supply livestock production for an expanding human population having a growing desire for seafood. Aquaculture is currently the fastest growing sector of agriculture, but the high cost and limited supplies of marine feedstuffs for aquafeeds could ultimately limit production of foodfish. Replacement of marine feedstuffs poses a dilemma, however, as replacement of fish meal can affect animal growth, and replacement of fish oil in aquafeeds leads to altered fillet fatty acid profiles without the maximum benefit of high omega-3 (n-3) and long-chain polyunsaturated fatty acids (LC-PUFA) content. Two feeding trials were conducted to determine if poultry byproducts can replace fish meal and fish oil in diets for largemouth bass Micropterus salmoides without affecting production performance or fillet fatty acid composition. Poultry byproducts were able to replace fish meal and fish oil while maintaining production performance of largemouth bass, however, the altered fatty acid profiles of the feeds were reflected in the fillets. Finishing diets containing high levels of fish oil were implemented to restore n-3 and LC PUFA concentrations in the fillet. Twelve weeks of finishing proved suitable to partially restore n-3 and LC-PUFA concentrations while limiting the overall use of marine resources in the largemouth bass production cycle.
7

Depozice dietárních mastných kyselin ve vybraných vnitřních orgánech a tkáních pokusných živočichů

Štumarová, Klára January 2019 (has links)
This diploma thesis deals with the issue of fatty acids containing distribution, metabolism, physiological properties and effects on health. In the experimental part there is detail descripiton of the experiment, where the amount of dietary fatty acids in the liver and visceral fat in rats was determined. Rats were divided into five groups, each of that was fed with mixture with 8% oil addition (palm oil, fish oil, safflower oil and Schizochytrium extract). The last group was fed with the mixture without any oil addition. The results of the experiment point to a high SFA content in feed with 8% fish oil addition. Although fish oil contains a significant amount of n-3 PUFA, high deposition of SFA could have negative effects on plasma lipid and lipoprotein levels. The most suitable oil is Schizochytrium microalga extract, which has a positive effect on EPA and DHA deposition, but does not contain significant amount of SFA, MUFA and PUFA n 6. Regarding the ratio of PUFA n-6/n-3, fish oil appears to be the second most suitable. The least suitable PUFA n-6/n-3 ratio is observed in safflower and palm oil.
8

Carcass characteristics, fatty acids, stearoyl-coa desaturase gene expression and sensory evaluation of calf-fed and yearling-fed angus steers

Brooks, Matthew Alan 15 May 2009 (has links)
There is a growing interest in documenting the effect of diet on the ability to convert saturated fatty acids (SFA) to monounsaturated fatty acids (MUFA) by modulating expression of the SCD gene. We propose that if cattle were raised to a constant body weight, their MUFA:SFA ratio will be the same regardless of being calf-fed (CF) or yearling-fed (YF). Twenty-four Angus cattle were acquired for this study. Cattle were slaughtered at weaning at 8 mo of age (SFCF, n=4), eight steers were assigned to the CF group and slaughtered at 12 mo of age (MFCF, n=4) and 16 mo of age (LFCF, n=4). Twelve cattle were assigned to the YF group and slaughtered at 12 mo of age (SFYF, n=4) 16 mo of age (MFYF, n=4) and market weight of 525 kg (LFYF, n=4). Cattle were then statistically analyzed based on time on high energy diet. Fatty acids from digesta, plasma, liver, L. dorsi, and s.c. and i.m. adipose tissue were all analyzed by FAME. In s.c. 18:1 and 16:1 were greatest in LFCF (41.27% and 5.58%, respectively, P = 0.05), and 18:0 and 16:0 did not differ between groups (P > 0.10). MUFA:SFA ratios of s.c. tended to be higher in LFCF animals (1.26) vs. LFYF (1.06, P = 0.10). However, there was no difference seen when comparing CF to YF animals (P = 0.26). MUFA:SFA ratio was higher in i.m. (P = 0.03) and also increased with age (P < .01). A trained sensory panel saw no significant differences between palatability of flavor characteristics of cooked steaks from LFCF, MFYF, or LFYF (P > 0.05). We showed increased SCD gene expression in the LFYF (248.41 to 1528.69 SCD/GAPDH, P = 0.01). Expression was higher in YF (P = 0.04), but their initial deposits of SFA, combined with the lack of SCD expression while on pastures, prevented the MUFA:SFA ratio from increasing at a rate fast enough to change the final ratios in the animal.
9

Carcass characteristics, fatty acids, stearoyl-coa desaturase gene expression and sensory evaluation of calf-fed and yearling-fed angus steers

Brooks, Matthew Alan 15 May 2009 (has links)
There is a growing interest in documenting the effect of diet on the ability to convert saturated fatty acids (SFA) to monounsaturated fatty acids (MUFA) by modulating expression of the SCD gene. We propose that if cattle were raised to a constant body weight, their MUFA:SFA ratio will be the same regardless of being calf-fed (CF) or yearling-fed (YF). Twenty-four Angus cattle were acquired for this study. Cattle were slaughtered at weaning at 8 mo of age (SFCF, n=4), eight steers were assigned to the CF group and slaughtered at 12 mo of age (MFCF, n=4) and 16 mo of age (LFCF, n=4). Twelve cattle were assigned to the YF group and slaughtered at 12 mo of age (SFYF, n=4) 16 mo of age (MFYF, n=4) and market weight of 525 kg (LFYF, n=4). Cattle were then statistically analyzed based on time on high energy diet. Fatty acids from digesta, plasma, liver, L. dorsi, and s.c. and i.m. adipose tissue were all analyzed by FAME. In s.c. 18:1 and 16:1 were greatest in LFCF (41.27% and 5.58%, respectively, P = 0.05), and 18:0 and 16:0 did not differ between groups (P > 0.10). MUFA:SFA ratios of s.c. tended to be higher in LFCF animals (1.26) vs. LFYF (1.06, P = 0.10). However, there was no difference seen when comparing CF to YF animals (P = 0.26). MUFA:SFA ratio was higher in i.m. (P = 0.03) and also increased with age (P < .01). A trained sensory panel saw no significant differences between palatability of flavor characteristics of cooked steaks from LFCF, MFYF, or LFYF (P > 0.05). We showed increased SCD gene expression in the LFYF (248.41 to 1528.69 SCD/GAPDH, P = 0.01). Expression was higher in YF (P = 0.04), but their initial deposits of SFA, combined with the lack of SCD expression while on pastures, prevented the MUFA:SFA ratio from increasing at a rate fast enough to change the final ratios in the animal.
10

Long Chain n-3 PUFA and Oleic Acid Modification Strategies to Enhance Fillet Quality in Tilapia, Oreochromis species

Chu, Hyun Sik Stephano 26 May 2017 (has links)
Tilapia are freshwater fish that have become important in aquaculture and as a stable global source of seafood due to their ability to thrive in different environments. However, tilapia are sometimes considered nutritionally undesirable due to their high n-6 to n-3 fatty acid ratios. A market study was conducted first to determine fatty acid compositions in tilapia fillets in different US markets. Then a research was conducted to enhance nutritional value of tilapia by improving the n-3 and oleic acid contents in fish fillets without compromising fish growth or feed conversion ratios. Feeds were formulated with combinations of high and low n-6, n-3, and oleic acid levels using soybean oil, fish oil, algae oil, and high-oleic sunflower oil. Then 12 diets, including a commercial diet, were assigned to 24 tanks, each with 25 tilapia per tank. A Recirculating Aquaculture System (RAS) was used to grow the fish for 8 weeks. Fatty acid compositions of tilapia fillets were determined and samples were vacuum packed and stored at -10oC and -20oC to test oxidative degradation and fatty acid compositional changes. The market survey data showed that there were significant differences in fatty acid composition, lipid content, and n-6:n-3 fatty acid ratios depending on the country of origin. Samples from USA had ideal n-6:n-3 ratios (1.3 ±0.85) while samples from Southeast Asia had higher n-6:n-3 fatty acids ratio (6.6 ±0.54). Algae oil incorporation significantly increased DHA level while fish oil incorporation significantly increased both EPA and DPA. High-oleic sunflower oil based diets improved oleic acid levels and reduced linoleic acid compared to the soybean oil based diets. Sensory evaluation indicated that lipid source did not significantly impact preference or overall fillet quality, including texture. Interestingly, a survey showed people were interested in value-added tilapia, and would pay up to 30% more for nutritionally enhanced fish compared to the $5.00/lb fresh fillet price currently available in supermarkets. There was no observable oxidation during long term frozen storage. The oxidation study proved that value-addition would not be compromised during the long term storage conditions, even under temperature abuse. It is possible to improve tilapia nutritional quality through diet to provide consumers with value-added products that maintain quality during frozen storage. / Ph. D.

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