Orientador: Cecilia Amelia Fazzio Escanhoela / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-12T22:27:25Z (GMT). No. of bitstreams: 1 Silva_GustavoHenriqueda_D.pdf: 4225256 bytes, checksum: 6254dc5eb8ce2f1f9c9ac0ffbce99d41 (MD5) Previous issue date: 2009 / Resumo: A esteatose hepática não relacionada ao alcoolismo pode ocorrer isoladamente ou fazer parte da doença hepática gordurosa não alcoólica (DGHNA). Esta abrange um amplo espectro de alterações morfológicas, variando desde a esteatose até um estágio mais grave, acompanhado por fibrose, podendo chegar à cirrose. O objetivo do nosso estudo foi avaliar e caracterizar a esteatose de causa não definida na infância, por meio de análise morfológica e morfométrica do tecido hepático. Dezoito biópsias provenientes de 16 pacientes com idade variando de 3 meses a 12 anos e 9 meses, com vaga dor abdominal e/ou mínima hepatomegalia associada a aumento discreto e persistente das enzimas hepáticas, foram analisadas através de microscopia de luz e eletrônica de transmissão. Nestes detectou-se esteatose macro e microvesicular "pura", ou seja, não acompanhada de fibrose ou de quaisquer outras alterações histológicas. Na microscopia de luz foi realizada a determinação semi-quantitativa da intensidade da esteatose total (macro e microvesicular), com classificação de 1 a 4 e a estimativa da porcentagem de hepatócitos afetados pela esteatose microvesicular em relação aos hepatócitos afetados pela macrovesicular; na microscopia eletrônica calculou-se a densidade mitocondrial por hepatócito e a área mitocondrial média utilizado-se em ambos os casos o programa TPS Dig versão 1.30. Dez pacientes com 1 a 14 anos de idade e com diagnóstico de normalidade em biópsia hepática foram utilizados como grupo controle. Os resultados obtidos mostraram predomínio de esteatose microvesicular entre os pacientes estudados (61%), com elevação significativa da área mitocondrial, sendo 1,52 ± 0,08 µm2 a área média para o grupo controle, 1,49 ± 0,07 µm2 para o grupo de esteatose macrovesicular e 2,92 ± 0,36 µm2 para o grupo de esteatose microvesicular. Não foram observadas alterações significativas na densidade mitocondrial, seja relacionada à esteatose microvesicular predominante ou à macrovesicular (72 ± 2 mitocôndrias/hepatócitos para o grupo controle, 70 ± 11 mitocôndrias/hepatócitos para o grupo de esteatose macrovesicular e 66 ± 8 mitocôndrias/hepatócitos para o grupo de esteatose microvesicular). Tampouco se observou correlação entre as variações dos valores das transaminases com ambos os tipos de esteatose, uma vez que para o grupo de esteatose microvesicular os valores médios foram AST = 62.9 ± 35.0, ALT = 125.9 ± 129.0 e GGT = 210.5 ± 278.3 e para o grupo de esteatose macrovesicular AST = 82.1 ± 97.5, ALT = 57.4 ± 41.4 e GGT = 185.8 ± 141.7. No grupo de estudo, a esteatose "pura", com pouca ou nenhuma sintomatologia clínica, associada ou não a alterações de transaminases, não relacionada à obesidade ou doença metabólica conhecida, mostrou-se predominantemente microvesicular e relacionada a aumento do volume mitocondrial. Nas hepatopatias mitocondriais primárias (HMP), principalmente por defeitos na cadeia respiratória, este tipo de alteração é comum. Devido a estas alterações mitocondriais, esta esteatose não deve ser denominada "pura" podendo, inclusive, corresponder à porção mais distal no longo espectro da DGHNA. Destacamos que, apesar da pouca manifestação clínica e laboratorial destas crianças, é fundamental o acompanhamento sistemático destas, havendo necessidade de maior atenção aos casos de esteatose na infância com predomínio da forma microvesicular. / Abstract: Hepatic steatosis unrelated to alcoholism may occur separately or be part of fatty liver disease (NAFLD). It encompasses a wide spectrum of morphologic alterations, ranging from steatosis to a more severe stage accompanied by fibrosis and cirrhosis. The aim of our study was to assess and characterize childhood steatosis of not defined cause carrying out morphologic and morphometric analysis of liver tissue. Eighteen biopsies from 16 patients with age varying from 3 months to 10 years, with vague abdominal pain and/or minimal hepatomegaly associated with slight and persistent increase in hepatic enzymes had been analyzed through light microscopy and transmission electron microscopy. On those patients, "pure" steatosis was detected, meaning it was not followed of fibrose or any other significant histological alterations. In light microscopy total steatosis was semi-quantified with estimative of macro- and microvesicular steatosis percentage and determination of predominant steatosis, classified from 1 to 4 and estimate the percentage of hepatocytes affected by steatosis microvesicular in comparison to hepatocytes affected by macrovesicular; in electron microscopy it was determined the degree of mitochondrial density in the hepatocytes and mean mitochondrial surface area using in both cases the TPS Dig version 1.30. Ten patients between 1 and 14 years old who had a normal diagnosis on liver biopsy were used as a control group. The results had shown microvesicular predominance of steatosis in the studied patients (61%) with significant increase of mitochondrial surface area values: 1,52 ± 0,08 µm2 in the control group, 1,49 ± 0,07 µm2 in the macrovesicular steatosis group and 2,92 ± 0,36 µm2 in the microvesicular steatosis group. Significant alterations in mitochondrial density were not observed, neither related to predominant micro nor macrovesicular steatosis (72 ± 2 mitochondrias/hepatocytes in the control group, 70 ± 11 mitochondrias/hepatocytes in the macrovesicular steatosis group and 66 ± 8 mitochondrias/hepatocytes in the microvesicular steatosis group). A correlation between variations in transaminases levels and both types of steatosis was also not observed, since for the microvesicular steatosis group the average values was AST = 62.9 ± 35.0, ALT = 125.9 ± 129.0 and GGT = 210.5 ± 278.3 and for the macrovesicular steatosis AST = 82.1 ± 97.5, ALT = 57.4 ± 41.4 e GGT = 185.8 ± 141.7. In our study group, "pure" steatosis, with little or no clinical symptoms, associate or not to alterations of transaminases and that did not correlate with obesity or known metabolic diseases is predominantly microvesicular and was related to increased mitochondrial volume. In the primary mitochondrial hepatopathies (PMH), especially for respiratory chain defects, this alteration is common. Due to these probable mitochondrial alterations, this steatosis doesn't have to be called "pure", being able, also, to correspond to the portion distal in the long specter of the NAFLD. It is important to emphasize that although the small number of clinical and laboratorial manifestations of these children, it is essential their systematic accompaniment. There is necessity of more attention to the cases with steatosis in pediatric group where microvesicular form predominance occurs. / Doutorado / Ciencias Biomedicas / Doutor em Ciências Médicas

Orientador: Daniel Barrera Arellano / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-25T11:28:26Z (GMT). No. of bitstreams: 1 Chaves_KamilaFerreira_M.pdf: 1834021 bytes, checksum: 17ab04d365f81e6b3faf3237da71b9f0 (MD5) Previous issue date: 2014 / Resumo: A redução do consumo de ácidos graxos saturados (AGS) na dieta, a fim de reduzir o risco de doenças cardiovasculares, tornou indispensável a busca por substitutos desse tipo de gordura, mediante novas alternativas tecnológicas, como a dos organogéis. O uso de estruturantes em sistemas lipídicos é visto como uma alternativa promissora, pois altera as propriedades físicas de óleos vegetais, sem que ocorram modificações químicas e aumento do teor de AGS, abrindo novas possibilidades para a produção de margarinas e spreads low sat e livres de ácidos graxos trans. O objetivo desse trabalho foi produzir margarinas utilizando a tecnologia de estruturação de óleos para reduzir a quantidade de AGS em comparação às margarinas comerciais convencionais. As matérias-primas, óleo de girassol alto oleico (OGAO), óleo de soja (OS), gordura interesterificada (GI), cera de candelilla (CC) e monoacilgliceróis (M), foram caracterizadas quanto a composição, qualidade e propriedades térmicas. O processo de elaboração das margarinas teste foi realizado em escala de bancada (1 kg), a fase lipídica foi fundida a 80ºC e misturada com a fase aquosa a uma temperatura de 60ºC, sob agitação de 300 rpm. O resfriamento até 30ºC ocorreu sob agitação a 37 rpm em uma sorveteira elétrica com parede de isolamento duplo, previamente resfriada em estufa B.O.D. a 5ºC. As margarinas comerciais avaliadas apresentaram composição de AGS entre 20,52 e 23,93% e teores de lipídios de 70 a 82%. A redução do teor de AGS foi calculada considerando a diferença da quantidade de AGS das margarinas teste em comparação com a média das margarinas comerciais. Foi possível notar através do planejamento experimental que quanto menores os teores de GI, CC e M nas formulações, maior a redução de AGS. As margarinas teste apresentaram melhor estabilidade da emulsão para as temperaturas avaliadas em comparação com as margarinas comerciais. Ocorreu maior exsudação de óleo nas margarinas comerciais em comparação às margarinas desenvolvidas conforme o planejamento experimental na temperatura de 35ºC por 48 horas. As margarinas testadas com OGAO e OS apresentaram menor valor na luminosidade (*L) em comparação às margarinas comerciais. A consistência e a espalhabilidade das margarinas testadas foram significativamente iguais a pelo menos 2/3 das margarinas comerciais avaliadas e a dureza foi estatisticamente igual para todas as margarinas testadas quando comparadas com as margarinas comerciais. Conclui-se que é possível produzir margarinas, mediante a tecnologia de estruturação de óleos, utilizando CC, M e GI como estruturantes, com redução do teor de AGS de 17,3 a 36,6% para as margarinas produzidas com OS e OGAO, respectivamente, em comparação com margarinas comerciais / Abstract: Reduce the consumption of saturated fatty acids (SFA) in the diet in order to reduce the risk of cardiovascular diseases, has made indispensable the search for substitutes for this kind of fat, through new technological alternatives, such as organogels. The use of structuring agents in lipid systems has been presented as a promising alternative, once that they change physical properties without any chemical modification or increase on the amount of SFA, which open new possibilities to the production of low sat and trans free margarines and spreads. The aim of this study was to produce margarines using oil structuring technology in order to reduce the amount of SFA compared to commercial margarines. Raw materials such as high oleic sunflower oil (HOSO), soybean oil (SO), interesterified fat (IF), candelilla wax (CW) and monoacylglycerols (M), were characterized due to their quality parameters, chemical composition and thermal properties. The processing of margarines were conducted in workbench scale (1kg per batch), the oil phase was melted, heating up to 80°C, and then mixed with an aqueous phase at 60°C, under controlled speed at 300 RPM. Cooling up to 30°C occurred under shear at 37 rpm using an electrical ice cream machine with a double wall isolated cube, previously cooled to 5°C. Commercial margarines with a SFA content between 20.52 and 23.93% and 70 to 82% amount of lipids were used as comparative standars. The reduction of SFA was calculated considering the amount of SFA on trial margarines and commercial comparative standards. It was possible to notice, through an experimental design, that smaller amounts of IF, CW and M on the formulations, resulted on reduction of SFA. Trial margarines presented better emulsion stability that commercial products. A higher oil exudation occurred for commercial margarines compared to the trial samples at 35°C for 48 hours. Tested margarines using HOSO and SO presents lower luminosity values (*L) when compared to commercial ones. Consistency and spreadability of trial margarines were statistically equal to, at least, 2/3 of the commercial margarines evaluated and hardness presented no statistical difference among all trial margarines when compared to commercial margarines. In conclusion, margarines produced by oil structuring technology using CW, M and IF as structuring agents, reduced the amount of SFA from 17.3 up to 36.6% in trial margarines with SO and HOSO, respectively when compared to commercial margarines / Mestrado / Tecnologia de Alimentos / Mestra em Tecnologia de Alimentos

Master of Science / Department of Animal Sciences and Industry / Teresa L. Douthit / Supplementation of lipids in the form of triglycerides is a safe method for increasing energy density in equine diets; however the effects of calcium salts of fatty acids (CSFA) on nutrient digestibilities in the horse are unknown. Eight cecally cannulated Quarter Horses were utilized in a crossover design in which horses consumed 1.5% BW smooth bromegrass hay and 0.5% BW concentrate supplemented with 4.1% soybean oil (SB) or 4.9% Enertia s/f® (E), a proprietary CSFA, for 28 d. Feces were collected for determination of apparent total tract digestibility of nutrients, and cecal digesta was evaluated for pH and concentrations of VFA and LCFA. Serum was collected following a 16-h fast and analyzed for triglycerides and cholesterol. Apparent total tract digestibilities of DM, NDF, ADF, CP, ether extract, and GE were unaffected by lipid source (P > 0.10). Serum triglycerides tended to be greater in horses consuming E compared to SB (P = 0.10); but, serum cholesterol concentrations were not different (P = 0.45). Cecal pH was unaffected by lipid source. Cecal concentration of total VFA tended to be greater in horses consuming SB compared to E at 2-h post feeding (P = 0.07). Cecal propionate concentrations were greater at 2-h post feeding for horses fed SB compared to horses fed E (P = 0.03). A treatment × time interaction was detected for total cecal LCFA concentration in which total cecal LCFA were greater in horses consuming E compared to SB at 2-h following consumption of a meal but became more similar as time progressed (P < 0.01). Secondly, an in vitro study was conducted to determine the effect of Co chloride on fermentation parameters using an equine cecal fluid inoculum in a 2 × 5 factorial arrangement of treatments. Alfalfa or smooth bromegrass hay (5 g DM) were utilized as substrates and were supplemented with 0.0, 0.5, 5.0, 25.0, or 50.0 mg Co/kg substrate DM. Cultures containing alfalfa had greater IVDMD compared to those with smooth bromegrass hay (P < 0.01). There was a forage × Co interaction in which gas production increased with time and was greater in cultures containing alfalfa (P < 0.01). Production of acetate, propionate, butyrate, isobutyrate, isovalerate, and total VFA, as well as acetate:propionate, were increased in cultures containing alfalfa compared to those containing brome hay (P < 0.05).

Abstract The semi-domesticated reindeer is a northern species of Cervidae that is exposed to extreme seasonal changes in temperature and nutrition in its living environment. The objective of this study was to examine the significance of thermogenic brown adipose tissue (BAT) for the survival of newborn reindeer in the cold during the critical perinatal period. The other main objective was to study the effect of wintertime undernutrition on serum and bone marrow fatty acid composition in yearling reindeer, with particular attention on the proportions of unsaturated and polyunsaturated fatty acids (PUFAs) and their feasibility as indicators of nutritional status. The results showed that the most of the adipose tissues in newborn reindeer were functionally active BAT. The tissue had specific anatomical locations, specialized cell morphological structure, high aerobic capacity, and tissue-specific mitochondrial 32000 Mr-uncoupling protein (UCP1) that is considered a rate-limiting factor for thermogenesis. The most readily mobilized fatty acids from BAT triacylglycerols were arachidonic, linoleic, and α-linolenic acids. BAT was most active at birth and during the close perinatal period but its aerobic capacity declined during the first month of life while UCP1 disappeared and the tissue gradually adopted the histological characteristics of white adipose tissue. The newborn reindeer had very low proportions of the principal C18-PUFAs, linoleic and α-linolenic acids, in serum lipids. However, the proportions of C18-PUFAs increased during the first few days of life by a rate that suggests a selective retention of these fatty acids from milk lipids. A prolonged restricted feeding of reindeer with lichen during winter and spring induced significant reductions in the proportions of linoleic and α-linolenic acids in serum cholesteryl esters and phospholipids, while proportion of arachidonic acid and serum prostaglandin PGF2α metabolite concentration increased. Plasma leptin and insulin levels decreased in parallel with decreases in feed intake and body weight. In freely ranging reindeer, the proportions of oleic acid and principal C18-PUFAs were significantly reduced in femur bone marrow triacylglycerols as a result of a wintertime undernutrition. In conclusion, active BAT is the dominant adipose tissue type in the newborn reindeer and it is likely to have a major significance on the thermoregulatory heat production and cold resistance of reindeer during the perinatal period. The changes in the specific PUFA proportions of serum and bone marrow lipids refleict the changes in the nutritional status and suggest that these fatty acids are preferentially utilized during prolonged wintertime undernutrition.

No description available.

This thesis describes an attempt to increase the life span of mice after injection of a leukemic tumor. Fatty acids were used as a protecting agent against the leukemic tumor.

Cyanobacteria (blue-green algae) produce a diverse array of toxic or otherwise bioactive metabolites. These allelochemicals may also play a role in defense against potential predators and grazers, particularly aquatic invertebrates and their larvae, including mosquitoes. Compounds derived from cyanobacteria collected from the Florida Everglades and other Florida waterways were investigated as insecticides against the mosquito Aedes aegypti, a vector of dengue and yellow fever. Screening of cyanobacterial biomass revealed several strains that exhibited mosquito larvicidal activity. Guided via bioassay guided fractionation, a non-polar compound from Leptolyngbya sp. 21-9-3 was found to be the most active component. Characterization revealed the prospective compound to be a monounsaturated fatty acid with the molecular formula C16H30O2. This is the first evidence of mosquito larvicidal activity for this particular fatty acid. With larvicidal becoming more prevalent, fatty acids should be explored for future mosquito control strategies.

Background and Aim: Microalgae are a potential economical source of omega-3 fatty acids, which are known for their health benefits. Omega-3 fatty acids derived from microalgae are however still expensive due to high costs involved in production. These costs can partly be attributed to cultivation of microalgae in unialgal cultures, which are prone to contamination, difficult to scale up and require stringent control of growth conditions. This study therefore is aimed to investigate the feasibility of using a mixed microalgae culture for the production of omega-3 fatty acids. Methods and materials: The microalgae were grown under uncontrolled conditions in a hanging-bag photo-bioreactor, with only the phosphorus-nitrogen ratio (P:N-ratio) varied. Variations in the different population proportions in the culture were studied and related to the biomass, total fatty acid and omega-3 fatty acid productivity of the culture. Finally, a comparison was made between the results obtained in this study and similar studies found in literature. Results and discussion: The mixed culture used was composed of several green microalgae, whose proportions varied with P:N-ratio, season, and age of the culture. Different interactions between the populations were observable, and these were thought to influence the culture’s biomass, total fatty acids (TFAs) and omega-3 fatty acid productivity. The TFA content of the culture was ~10-20% by the end of the exponential phase, depending on the nutrients supplied. The fatty acids were composed of mostly unsaturated fatty acids, the majority of which were omega-3 fatty acids; C18:3ω3 (up to 50% of TFA), C16:4ω3 (up to 15%) and C18:4ω3 (up to 5%). Other fatty acids observed included C16:0 (up to 25%), C18:1ω9/C18:1ω8 (up to 20%), C18:2ω6 (up to 5%), traces of C18:0, C18:3ω6, C17:0, C16:3ω3 and C16:1ω7 were also detected. The presence of these fatty acids was found to vary depending on season, P:N-ratio, and age of the culture. When compared to studies in the literature, the mixed culture was found to perform better than, or as well as reported studies, where unialgal cultures were cultivated under controlled laboratory conditions. Conclusion: In view of the reported advantages of cultivating mixed cultures, the production of omega-3 fatty acids via such cultures appears attractive. More research however is needed to optimise the culture; study interactions between the organisms and their effect on biomass, total fatty acid and omega-3 fatty acid productivity. Finally, the economic implications of using mixed cultures need to be evaluated as well.

Microbiota are present in large numbers and as a diverse population within the gastrointestinal tract. There are approximately 400 different species of microbiota which may be beneficial, harmful or both, but each play an important role in the regulation and modulation of the hosts’ bowel processes (McOrist et al. 2008; Dethlefsen et al. 2008). Many of these colon microbiota allow for saccharolytic fermentation of non-digestible dietary fibres and carbohydrates into by-products and intermediates, followed by a subsequent conversion into short chain fatty acids (SCFAs) (mainly n-butyric acid, propionic acid and acetic acid) each of which play an important role in maintaining colon homeostasis (Topping & Clifton 2001). A balance of ‘good’ microbiota (e.g., Bacteroides spp./ Bifidobacteria spp.) and ‘bad’ microbiota (e.g., Veilonellae) and the optimal production of various SCFAs within the gut could possibly allow for proper functioning of the large intestine and assist in decreasing the onset of various colonic disorders such as Irritable Bowel Syndrome (IBS). The sample group for the study consists of male and female patients, with an average age of 40 to 50 years old, whom of which have been diagnosed with either constipation IBS (C-IBS) or diarrhoea IBS (D-IBS) via the Rome III criteria system for IBS diagnosis. DNA and SCFA extractions were optimised for human stool, colonic fluid and tissue biopsy sample obtained from the aforementioned patients. Optimization steps allowed for starting material with high analysis integrity. Different methods of microbiota analysis, such as ARISA, were investigated; however, real-time qPCR was selected as the best method to identify and quantify specific microbiota. Extracted SCFAs were separated via gas chromatography and identified and quantified via Mass Spectrometry. Significant changes in microbial content and SCFA profiles were found to be associated with healthy and IBS patients. Results obtained would however be influenced by external factors typical of clinical studies of this nature. This study allows for opportunities for future research into understanding IBS.

Docosahexaenoic acid (22:6n-3) and arachidonic acid (20:4n-6) are deposited in large amounts in membrane phospholipids of the developing central nervous system (CNS). High levels of 22:6n-3 are found in synaptic terminals and retina, and are important for normal visual development and function. 20:4n-6 and22:6n-3 are supplied in human milk. In contrast, infants fed formula rely completely on endogenous synthesis of 20:4n-6 and 22:6n-3 from linoleic (18:2n-6) and a-linolenic (18:3n-3) acid, respectively. Levels of 22:6n-3 in the blood lipids of infants fed formula are lower than in infants fed human milk. Concern over the supply of 22:6n-3 led to clinical trials in which premature infants were fed formulas containing fish oils as a source of 22:6n-3. Piglets, which have a similar lipid metabolism and perinatal timing of the brain growth spurt to humans, have a lower percentage of 22:6n-3 in blood, liver and CNS tissues when fed formula with 30% of fatty acids as18:2n-6 and 0.8% 18:3n-3, compared to sow milk. It was hypothesized that the low blood and tissue 22:6n-3 in formula-fed piglets was due to inappropriate quantities and/or ratios of dietary 18:2n-6 and 18:3n-3 limiting the synthesis of 22:6n-3. Thus, the main objectives of this thesis were to determine. (1) if 22:6n-3 is an essential dietary nutrient for the term gestation piglet, (2) if appropriate quantities and ratios of 18:2n-6 and 18:3n-3 in formula will support CNS membrane accretion of 20:4n-6 and 22:6n-3, comparable to piglets fed varying amounts of 22:6n-3 in natural milk, and (3) if lower blood phospholipid 22:6n-3 consistently reflects reduced 22:6n-3 in the CNS. Initial studies (Experiment I) showed that formula with 4% 18:3n-3 supported a similar percentage of22:6n-3 in piglet liver and CNS membrane lipids to sow milk, but was associated with lower brain weight. Deposition of 22:6n-3 in brain was influenced by the formula 18:3n-3 content. The 18:2n-6:18:3n-3 ratio (22:1and 37:1) seemed to be important, however, when formulas contained 1% 18:3n-3. Low levels of fish oil in formula, similar to those used in clinical trials, were effective in supplying 22:6n-3 to the developing piglet brain (Experiment II). The efficacy of 18:3n-3 in supporting the deposition of 22:6n-3 in the brain was estimated to be at least 20% that of dietary 20:5n-3 plus 22:6n-3. With increasing dietary fish oil, however, levels of eicosapentaenoic acid (20:5n-3) increased and 20:4n-6decreased in plasma, liver and retina, but not brain (Experiment III). This suggests regulatory mechanisms may exist to maintain relatively constant levels of 20:4n-6 and 20:5n-3 in brain. Milk 22:6n-3 varies with maternal intake of 22:6n-3. The effect of milk 22:6n-3 content was studied in piglets fed milk with 0.1% or 1.5% 22:6n-3 obtained from sows fed usual pig diets containing vegetable fats without or with fish oil, respectively (Experiment IV). Consumption of 1.5 vs 0.1% 22:6n-3 from sow milk resulted in 300% higher 22:6n-3 in liver and blood phospholipids and 11% higher 22:6n-3 in cerebrum of nursing piglets. Despite similar milk 20:4n-6, the % 20:4n-6 in tissues other than the brain was lower in piglets fed high22:6n-3 sow milk. Thus, high intakes of n-3 fatty acids decrease 20:4n-6 in piglet liver and blood lipids. The blood phospholipid % 22:6n-3 in piglets fed formulas containing 18:2n-6 and 18:3n-3 but not their long-chain derivatives, was lower than in piglets fed 22:6n-3 in natural milk, consistent with published findings in formula-fed infants. However, in contrast to circulating lipids, formulas with 4% 18:3n-3 maintained similar levels of 22:6n-3in the piglet CNS compared to milk. These studies show that blood phospholipid 22:6n-3 and 20:4n-6 are not specific indices of effects in CNS lipids. This thesis has shown (1) 22:6n-3 is not essential in the diet of the term piglet, if adequate 18:3n-3 is given, (2) fish oils are an effective source of 22:6n-3 for deposition in the developing brain, (3) high dietary n-3fatty acids interfere with 20:4n-6 metabolism, and (4) blood lipid 20:4n-6 and 22:6n-3 do not accurately reflect CNS fatty acids. / Land and Food Systems, Faculty of / Graduate