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Thesis (M.Sc.)--University of Alberta, 1997. / Submitted to the Faculty of Graduate Studies and Research in partial fulfilment of the requirements for the degree of Master of Science, Department of Agricultural, Food and Nutritional Science. Also available online.

Essential fatty acids are necessary for growth, survival, and development of larval fishes, but there is limited information on the essential fatty acid requirements of larval southern flounder (Paralichthys lethostigma). The objectives of this study were to elucidate connections between dietary supply of docosahexaenoic acid (DHA) and arachidonic acid (ARA) and deposited fatty acids in the head or body, and then link diet and stored fatty acids in the head or body with larval quality traits. From 4-15 days posthatch (dph), southern flounder larvae were fed rotifers enriched with four different combinations of DHA-rich Algamac 3050 and ARA-rich Algamac ARA. Fatty acid concentrations in the head and body were measured at 15 dph, and relationships between fatty acids in head or body and in the diet were determined. Larval quality traits, including specific growth rate (SGR), survival, and eight behavioral performance variables were measured. Results showed that concentrations of DHA and ARA in the head and in the body were correlated with concentrations of DHA and ARA in the diet. Growth rate did not vary among the four diets, but survival was positively correlated with the amount of lipid in the diet. Responsiveness to a visual stimulus was positively correlated with the concentration of DHA in the diet, the ratio DHA:EPA in the head, and total energy content of the diet. Turning rate during routine swimming was correlated with body DHA. This study demonstrates the influence of DHA content, total lipid content, and energy levels in the diet of southern flounder and provides a foundation for future studies examining causal factors of recruitment variability or larviculture production success. / text

Orientador: Alexandre Ninhaus Silveira / Resumo: Os peixes durante o período reprodutivo, mobilizam grande parte de suas reservas energéticas para o processo de maturação dos oócitos, por isso quando em cativeiro, é necessário o fornecimento de uma dieta nutricionalmente adequada, com cuidado com o manejo alimentar e a escolha da ração, aonde os reprodutores devem receber uma dieta com componentes de alta qualidade e digestibilidade. O objetivo foi verificar se a adição de 5% de óleo de peixe marinho a dieta Gymnocorymbus ternetzi promoverá uma incorporação de ácidos graxos essenciais no tecido ovariano e possível alteração no desenvolvimento gonadal. Para tal, foram estabelecidos dois sistemas compostos com espécimes adultos de G. ternetzi, sendo um denominado grupo controle - GC, em que os animais foram alimentados com ração comercial e o outro grupo óleo - GO que foram alimentados com a mesma ração com adição de 5% de óleo de peixe marinho, por um período de 12 meses. Mensalmente, foram realizadas coletas do tecido hepático e gonadal de fêmeas de G. ternetzi, para determinação dos índices hepatossomático (IHS) e gonadossomático (IGS), para quantificação e determinação do tamanho dos oócitos, para análise das fases reprodutivas e determinação quanto ao perfil dos ácidos graxos. Os dados de biometria dos animais, não diferiram estatisticamente entre os grupos testados. A determinação dos ácidos graxos dos tecidos hepático e gonadal, apresentou valores constantes e similares de ácidos graxos poli-insaturados - família ômega... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Fish during the reproductive period mobilize most of their energy reserves for the oocyte maturation process, so when in captivity, it is necessary to provide a nutritionally adequate diet, careful with food management and choice of feed, where breeders should receive a diet with high quality components and digestibility. The objective was to verify if the addition of 5% of marine fish oil to the Gymnocorymbus ternetzi diet will promote the incorporation of essential fatty acids in the ovarian tissue and possible alteration in gonadal development. For this purpose, two composite systems were established with adult G. ternetzi specimens, one called control group - GC, in which the animals were fed with commercial feed and the other oil - GO group that were fed with the same feed with the addition of 5% marine fish oil for a period of 12 months. The liver and gonadal tissue were collected monthly from G. ternetzi females to determine hepatosomal (IHS) and gonadosomatic indices (IGS), to quantify and determine oocyte size, to analyze the reproductive phases and to determine the profile. of fatty acids. Animal biometrics data did not differ statistically between the groups tested. The determination of fatty acids from hepatic and gonadal tissues presented constant and similar values of polyunsaturated fatty acids - omega 3 family (PUFAs n3) for both groups. The gonadosomatic index (IGS) did not differ statistically between the groups, but the hepatosomatic index (IHS), in April /... (Complete abstract click electronic access below) / Mestre

Novas alternativas de produção de ácidos graxos altamente insaturados n-3 (HUFA n-3) são procuradas mediante várias abordagens experimentais na área aquícola considerando que a oferta atual de óleos marinhos é limitada. Como os ácidos graxos das séries n-3 e n-6 são metabolizados mediante os mesmos processos enzimáticos, o aporte de ácidos graxos essenciais da dieta poderia influenciar nos níveis de alongamento e desaturação em função da disponibilidade relativa destes compostos. O objetivo deste trabalho foi determinar a influência de diferentes relações 18:3n3/18:2n6 (ALA/LA - ácido linolênico/ácido linoleico) de rações exclusivamente vegetais, sobre o metabolismo de ácidos graxos de juvenis de pacu (Piaractus mesopotamicus). Inicialmente 18 unidades experimentais (caixas com 16 peixes) foram alimentadas por 34 dias (C1) com uma dieta controle (tratamento T6) contendo óleo de tilápia como único ingrediente de origem animal. Posteriormente, foram formados aleatoriamente, 6 grupos com 3 unidades experimentais cada. Em uma segunda fase, durante 72 dias, 5 grupos receberam dietas, contendo óleo de linhaça e soja em substituição ao óleo de tilápia, com relações calculadas de ALA/LA de: 2,98 (T1); 1,68 (T2); 1,03 (T3); 0,61 (T4) e 0,35 (T5) e um grupo continuou com a dieta controle (T6). Nesta segunda fase, determinaram-se parâmetros de desempenho zootécnico e metabolismo de ácidos graxos em 3 intervalos de 24 dias (C2=58 dias, C3=82 dias e C4=106 dias). Os animais apresentaram crescimento e ganho de peso sem diferenças significativas entre os grupos e com aumento progressivo da proporção de gordura corporal total. A composição de ácidos graxos da dieta influenciou de forma proporcional sobre a composição da maioria de ácidos graxos de corpo inteiro. Os coeficientes de digestibilidade aparente aumentaram conforme o grau de instauração dos ácidos graxos e sua abundância relativa na dieta. A concentração de ácidos graxos polinsaturados nos lipídios de corpo inteiro não diferiu entre a maioria de tratamentos. O teor e aparecimento do ácido graxo 20:5n3 (EPA) e a atividade da enzima Δ-5 desaturase dos grupos T1, T2 e T3 foi menor que os demais tratamentos no período C4. O aparecimento de HUFA n-3 e n-6, atividade Δ-6 desaturase total e atividade Δ-6 desaturase sobre os ácidos graxos n-3 totais dos tratamentos T1 a T5 foram maiores que no T6 (controle). Estes resultados demonstram que o pacu (Piaractus mesopotamicus) é capaz de alongar e desaturar ácidos graxos essenciais para produzir ácidos graxos altamente insaturados (ácidos graxos com no mínimo 20 C e 3 ligações duplas - HUFA). Esta atividade é diminuída pela presença, mesmo em quantidades pequenas, de HUFA na dieta. Além disso, sugerem que relações ALA/LA da dieta, iguais ou maiores que 1, provocam diminuição na taxa de produção de 20:5n3, nos níveis testados neste estudo. / New alternatives for production of highly unsaturated fatty acids n-3 (n-3 HUFA) are sought by various experimental approaches in aquaculture, considering that the current supply of marine oils is limited. Since fatty acids of the n-3 and n-6 series are metabolized by the same enzyme processes, the supply of essential fatty acids of the diet could influence the elongation and desaturation levels, depending on the relative availability of these compounds. The objective of this study was to determine the influence of different 18:3n-3/18:2n-6 ratios (ALA/LA - linolenic acid/linoleic acid) of diets containing exclusively vegetable ingredients on the metabolism of fatty acids, of pacu juveniles (Piaractus mesopotamicus). Initially, 18 experimental units (boxes with 16 animals) were fed a control diet (T6 treatment) containing tilapia oil as the sole animal ingredient for 34 days (C1). Later, 6 groups with 3 experimental units each were formed at random. In a second phase, during 72 days, five groups were fed diets containing linseed and soy oils to replace tilapia oil, with calculated ALA/LA ratios: 2.98 (T1); 1.68 (T2); 1.03 (T3); 0.61 (T4) and 0.35 (T5) and a group continued with the control diet (T6). In the second phase were determined growth performance parameters and fatty acid metabolism in three intervals of 24 days (C2 = 58 days = 82 days and C3 C4 = 106 days). The animals showed growth and weight gain with no significant differences between groups and progressive increase in the proportion of total body fat. The fatty acid composition of the diet influenced proportionally on the composition of the majority of whole body fatty acids. The apparent digestibility increased as the degree of unsaturation of fatty acids and their relative abundance in the diet. The concentration of polyunsaturated fatty acids in whole body lipids did not differ among the most treatments. The content and appearance of the fatty acid 20:5n3 (EPA) and the activity of Δ-5 desaturase enzyme of groups T1, T2 and T3 was lower than the other treatments in C4 period. The appearance of n-3 and n-6 HUFA, Δ 6-desaturase activity and the total Δ 6-desaturase activity on the total n-3 fatty acids from T1 to T5 treatments were higher than T6 (control). These results demonstrate that pacu juveniles are able to elongate and desaturate essential fatty acids to produce highly unsaturated fatty acids. This activity diminishes by the presence of even small amounts of HUFAs in the diet. Moreover, it suggests that ALA/LA ratio of diet, equal to, or greater than one, cause a decrease in the rate of production of 20:5n3, within the levels tested in this study.

Os ácidos graxos trans competem com os ácidos graxos essenciais inibindo as enzimas envolvidas na síntese dos ácidos graxos polinsaturados de cadeia longa. Quantidades adequadas de ácidos graxos essenciais na dieta minimizam este efeito. No entanto, pouco se conhece da ação dos isômeros trans, sob condições de restrição ou deficiência dietética dos ácidos graxos essenciais, sobre o percentual de deposição tanto dos próprios isômeros trans, como dos ácidos graxos polinsaturados nos lipídios dos tecidos. Foram avaliadas dietas ricas em ácidos graxos trans e com diferentes concentrações de ácidos graxos essenciais em ratos. A incorporação de ambos foi proporcional à concentração na dieta, mas variou entre os tecidos estudados. Verificou-se que as quantidades de ácidos graxos trans incorporadas pelo tecido adiposo foi a maior, enquanto que o cérebro incorporou a menor quantidade. A despeito da incorporação dos ácidos graxos trans, o perfil de ácidos graxos do cérebro manteve-se estável em relação às variações dietéticas. Não se observou acúmulo dos ácidos graxos trans em função do prolongamento do consumo da dieta. Os ácidos graxos essenciais incorporados aos tecidos também foram modulados pela dieta, e em concentrações adequadas influenciaram na menor deposição dos isômeros trans no tecido adiposo, plasma e tecido cardíaco. Avaliando-se a composição dos ácidos graxos nos fosfolipídios do tecido cardíaco, observou-se que a fosfatidiletanolamina incorporou a maior porcentagem dos isômeros trans seguida da fosfatidilcolina e da cardiolipina, respectivamente. Embora tenha incorporado quantidades intermediárias dos ácidos graxos trans a fosfatidilcolina teve uma maior alteração no perfil de ácidos graxos em comparação aos demais. A reduzida concentração de ácidos graxos trans incorporados na cardiolipina das mitocôndrias e no cérebro sugere a existência de um mecanismo protetor para a manutenção da composição lipídica necessária às atividades funcionais. / Trans fatty acids compete with essential fatty acids inhibiting the enzymes of the long chain polyunsaturated fatty acids synthesis. Appropriate amounts of dietary essential fatty acids minimize this effect. However, little is known about the action of trans isomers on the deposition percentage of these own trans isomers itself or as polyunsaturated fatty acids in tissue lipids, when under dietary restriction or deficiency conditions of essential fatty acids. Diets high in trans fatty acids and with different concentrations of essential fatty acids were assessed. The incorporation of trans isomers and of essential fatty acids was proportional to their dietary concentration, but varied among the tissues studied. It was verified that the adipose tissue incorporated the largest amount of trans fatty acids while the brain incorporated the smallest. In spite of the trans fatty acids incorporation, the profile of brain fatty acids was maintained stable in relation to dietary variations. No accumulative deposition of trans fatty acids was observed in relation to extended length of time of dietary consumption Essential fatty acids incorporated in tissues were also modulated by diet and in moderate concentrations influenced the lower deposition of trans isomers in adipose tissue, blood plasma and heart. By assessing fatty acids composition in phospholipids of heart, it was verified that phosphatidylethanolamine incorporated the largest percentage of trans isomers followed by phosphatidylcholine and cardiolipin, respectively. Phosphatidylcholine presented the greatest change in fatty acids profile when compared to the others phospholipids, although incorporating intermediate amounts of trans isomers. The reduced concentration of trans fatty acids incorporated in cardiolipin and brain suggests that there is a protector mechanism for maintenance of the lipids composition required for functional activities.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2009. / Härtill 5 uppsatser.

Feeding experiments were conducted on Atlantic pollock (Pollachius virens) to examine the variability in tissue fatty acid (FA) composition and stable carbon isotope fractionation of FA during digestion, assimilation and mobilization of lipids. The FA profiles and compound-specific carbon isotopes of chylomicrons, liver, muscle and fasted serum were compared to diet. FA analysis demonstrated similarity among tissue groups despite differences in feeding states. The FA results indicate the blood of post-prandial fish may serve as an alternative to tissue biopsies for the estimation of marine fish diets with compound-specific isotope analysis (CSIA). Despite similarity among FA profiles, the carbon isotope discrimination factors of FA varied independently, which suggests that fractionation is influenced by the degree to which individual FA are oxidized. These results provide preliminary information that is necessary in order to use CSIA to estimate the effects of fish diets.

Conjugated linoleic acid (CLA) is produced in the rumen by isomerization of linoleic acid and has been shown to be anticarcinogenic. The objective of this study was to determine the effects of feeding dietary CLA to pre-ruminant lambs or linoleic acid-rich safflower oil to weaned ruminating lambs. Fat content, CLA content and fatty acid (FA) composition of diaphragm, leg, rib, subcutaneous (SC) adipose and liver tissues were determined. The triacylglycerol (TAG) fractions of the total lipid (TL) from the diaphragm, rib and SC adipose tissues were analyzed for FA composition and FA positional distribution. The phospholipid (PL) fractions of the TL were analyzed for FA composition. The positional (PL) fractions of the TL were analyzed for FA composition. The positional distribution of FAs of liver PL was determined. Tissue fat content was affected by diet only in SC adipose tissue. Dietary supplementation with safflower oil increased the fat content of the subcutaneous adipose tissue whereas CLA supplementation resulted in decreased (P<0.05) fat content. Dietary supplementation with safflower oil increased (P<0.05) the CLA content of tissues by more than 200% whereas dietary supplementation with CLA did not affect CLA content. Positional distribution analysis indicated that CLA tends was localized to the sn-1/3 positions of TAG and the sn-2 position of the liver PL. / xiii, 74 leaves : ill. ; 28 cm.

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