Two experiments were carried out to evaluate the effects of Pearl Millet in combination with different levels of flaxseed and natural pigment (Oro Glo 15RTM) on quantity of n-3 fatty acids in eggs, laying performance and yolk pigmentation. In the first experiment, six different diet treatments were used for six weeks, with 24 hens per treatment (three birds per cage, eight cage replicates). Control diet was a corn-soybean meal diet, and diets containing 0, 2, 4, 8 or 12% ground flaxseed in which all the corn was replaced by pearl millet. In the second experiment, the diet treatments consisted of pearl millet and three inclusion levels of ground flaxseed (4%, 6% and 8%) and two levels (0.1% and 0.2%) of natural pigment in a factorial arrangement. The experiment lasted for twelve weeks, with 18 hens per treatment (three birds per cage, six cage replicates). In each of the experiments, all the diets were formulated to be isocaloric and isonitrogenous and to meet or exceed NRC requirements. Body weight of the birds and feed consumption were recorded at weekly (first experiment) and biweekly (second experiment) intervals. Number of eggs and egg mass produced were measured and recorded on a daily basis. At the end of each of the experiments, all the hens were euthanized to determine liver integrity. In both of the experiments, flock performance parameters were not different among treatments. In regard to egg traits, in the second experiment after 8 week of the start of the experiment, birds fed with diets containing 8% flaxseed produced significantly ( P < 0.05) smaller eggs compared to hens fed 4% flaxseed. Yolk pigmentation was lower (P < 0.05) for the eggs produced by hens fed diets containing pearl millet compared with those produced by feeding corn-based diet. However, 0.1% or 0.2% inclusion of the pigment both proved to be suitable to restore yolk pigmentation to marketable levels. No difference was observed among diets in regard to liver haemorrhage. Evaluation of FA profiles indicated that birds fed a diet containing PM as the sole grain source, and low levels of flaxseed (6%) can produce eggs with more than 350 mg/egg of n-3 FA, which is the lower standard to market eggs as "n-3 FA enriched". / Keywords: laying hens, pearl millet, flaxseed, natural pigment, flock performance, eggs, liver haemorrhage.

Omega-3 enriched eggs serve as an important functional food to boost consumption of polyunsaturated fatty acids (PUFA) critical for good health. Because omega-3 eggs have the potential for unpleasant aromas and flavours, this research was designed to assess the fatty acid profile and sensory attributes of eggs procured from hens consuming designer diets. In the first study, the use of hemp in hen diets led to significant increases in omega-3 PUFA content and colour intensity of yolks, but did not have adverse effects on the sensory profiles of cooked eggs. Additionally, the level of docosahexaenoic acid was the same in eggs from both the lowest and highest hempseed oil groups. In order to overcome this plateau, the second study assessed diets varying in linoleic acid (LA) content. Although docosapentaenoic acid in the yolk was significantly increased with an increasing dietary LA content, docosahexaenoic acid remained unaffected by dietary treatment. In the third study, a different approach was used to reduce competition between alpha-linolenic acid (ALA) and LA. Diets containing two levels of ALA and varying ratios of saturated fatty acids (SFA): LA + oleic acid (OA) were tested. Increasing dietary SFA: LA + OA resulted in marked increases in all n-3 PUFA. The fourth study was designed to assess the interaction between dietary constituents on sensory attributes of eggs, namely omega-3 PUFA from flaxseed oil (FO), and canola meal (CM), which contains precursors to trimethylamine, which may lead to fishy taint. Oceanic flavour significantly increased with inclusion of FO, while egg, creamy and buttery flavours showed a decrease. The pairing of CM and FO resulted in a significant decrease in egg flavour compared to using FO alone. This research has demonstrated that novel ingredients like hemp can be used in laying hen diets to deposit n-3 PUFA into eggs without fear of affecting sensory outcomes. Increasing the SFA: LA + OA ratio in layer diets is most effective in increasing yolk ALA conversion into long-chain PUFA. Lastly, CM should be added to diets with caution when used in conjunction with omega-3 PUFA ingredients due to a reduction in egg flavour.

Diets high in saturated fatty acids are associated with the development of circadian dysregulation, obesity, and type 2 diabetes mellitus. Conversely, unsaturated fatty acids are now known to improve insulin sensitivity, reduce weight gain, and alleviate obesity-induced inflammation. The aforementioned effects of saturated and unsaturated fatty acids have also been identified in the hypothalamus; however, there is a paucity of studies regarding the role of unsaturated fatty acids in circadian rhythms. Therefore, a novel cell model was established to examine the effects of omega-3 fatty acids on circadian rhythms in hypothalamic neurons. The mHypoE-37 cell line expresses Bmal1, Per2, and Rev-erbα in a circadian manner. The saturated fatty acid, palmitate, was found to induce circadian dysregulation of the mHypoE-37 neurons, whereas the unsaturated fatty acid, docosahexaenoic acid, protected against palmitate-induced circadian changes. These studies are the first to identify the potential for unsaturated fatty acids to protect the circadian system.

Diets high in saturated fatty acids are associated with the development of circadian dysregulation, obesity, and type 2 diabetes mellitus. Conversely, unsaturated fatty acids are now known to improve insulin sensitivity, reduce weight gain, and alleviate obesity-induced inflammation. The aforementioned effects of saturated and unsaturated fatty acids have also been identified in the hypothalamus; however, there is a paucity of studies regarding the role of unsaturated fatty acids in circadian rhythms. Therefore, a novel cell model was established to examine the effects of omega-3 fatty acids on circadian rhythms in hypothalamic neurons. The mHypoE-37 cell line expresses Bmal1, Per2, and Rev-erbα in a circadian manner. The saturated fatty acid, palmitate, was found to induce circadian dysregulation of the mHypoE-37 neurons, whereas the unsaturated fatty acid, docosahexaenoic acid, protected against palmitate-induced circadian changes. These studies are the first to identify the potential for unsaturated fatty acids to protect the circadian system.

Incorporation of full-fat flaxseed, and to a lesser extent, canola seed in diets to produce n-3-enriched products has attracted interest in the poultry industry. However, high amounts of nonstarch polysaccharides (NSP) in oilseeds compromise their nutritive value. The objectives of the current research were to develop enzyme supplements effective in cell wall depolymerization and viscosity reduction, particularly in flaxseed; to evaluate the effects of enzyme addition and feed processing on oil utilization and egg n-3 fatty acid deposition in broiler chickens and laying hens fed oilseed-containing diets; to characterize the NSP hydrolysis products and to investigate the effects of diet type and enzyme addition on growth performance and the incidence of necrotic enteritis (NE) in broiler chickens challenged with Clostridium perfringens. Results showed that diets containing high levels of flaxseed reduced egg production and shell quality in laying hens, and impaired final body weight and feed conversion ratio (FCR) in broiler chickens. Reducing flaxseed particle size via grinding did not improve the growth performance of broiler chickens, whereas diet pelleting showed more pronounced and beneficial effects in improving the nutritive value of flaxseed, particularly when intact seeds were used. Multicarbohydrase supplementation resulted in a significant depolymerization of cell wall polysaccharides in soybean, canola and flaxseed meals, which was followed by the production of water-soluble NSP hydrolysis products, and the reduction of flax mucilage viscosity in vitro was also evident. Enzyme addition to flaxseed-containing diets improved FCR of broiler chickens and egg production performance of laying hens, and facilitated egg n-3 fatty acid deposition. The C. perfringens challenge caused intestinal NE lesions and increased the mortality of broiler chickens with the highest NE mortality and intestinal C. perfringens counts observed in those fed flaxseed-containing diets. Enzyme supplementation to diets containing high levels of water-soluble NSP (wheat/barley- or wheat/barley/flaxseed-based) facilitated post-disease compensatory growth in pathogen challenged birds. This was accompanied by a numerical reduction of intestinal C. perfringens by 1.4 log10 cfu/g in birds fed the flaxseed-containing diets. Such findings indicated that enzyme addition may be used as a nutritional strategy to reduce the risk of NE development in broiler chickens.

The omega-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA), in the free fatty acid (FFA) form, has been demonstrated to reduce adenoma number and size in patients with familial adenomatous polyposis. However, the mechanistic basis of the antineoplastic activity of EPA in the colorectum remains unclear. We tested the hypothesis that EPA-FFA negatively modulates synthesis of and signaling by prostaglandin (PG) E(2) in human colorectal cancer (CRC) cells. EPA-FFA induced apoptosis of cyclooxygenase (COX)-2-positive human HCA-7 CRC cells in vitro. EPA-FFA in cell culture medium was incorporated rapidly into phospholipid membranes of HCA-7 human CRC cells and acted as a substrate for COX-2, leading to reduced synthesis of PGE(2) and generation of PGE(3). Alone, PGE(3) bound and activated the PGE(2) EP4 receptor but with reduced affinity and efficacy compared with its "natural" ligand PGE(2). However, in the presence of PGE(2), PGE(3) acted as an antagonist of EP4 receptor-dependent 3',5' cyclic adenosine monophosphate induction in naturally EP4 receptor-positive LoVo human CRC cells and of resistance to apoptosis in HT-29-EP4 human CRC cells overexpressing the EP4 receptor. We conclude that EPA-FFA drives a COX-2-dependent "PGE(2)-to-PGE(3) switch" in human CRC cells and that PGE(3) acts as a partial agonist at the PGE(2) EP4 receptor.

Epidemiological studies have suggested that the consumption of fish may reduce the risk of cardiovascular disease. Compared to the number of studies using fish oils, few studies have used fish itself. Those which have used fish have generally used fattier fish such as mackerel and salmon as part of an uncontrolled diet. In this study, 23 healthy men consumed 200g each of Chinook salmon, Dover sole, and sablefish in a three-way crossover design for 18-day periods with three-week washout periods in between. The diets had the approximate composition of the 'Western' diet: 45% carbohydrates, 36% fat, and 16% protein with the sole diet containing 1.95 g omega-3 (n-3) fatty acids, the salmon diet 3.99 g n-3, and the sablefish diet 3.42 g n-3 fatty acids. Serum total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglycerides (TG), bleeding time (BT), blood pressure (BP), platelet aggregation (PA) using ADP and collagen as agonists, platelet fatty acid profiles (FAP), thromboxane B2 (TXB2) , and apolipoprotein B (Apo B) were measured at the beginning and end of each period. TC, and HDL-C, and TG changed significantly when compared to the prefish diet while both LDL-C and apo B demonstrated diet effect. LDL-C increased on both the salmon and sablefish diets (p = 0.08) compared to the sole diet, and increased approximately 15% on the former two diets compared to the prefish diet. Bleeding time was significantly longer when the salmon diet was consumed (p = 0.06). The impact of the three diets on PA depended upon the agonist. With collagen, only the sablefish diet decreased aggregation compared to the prefish diet. When ADP was used, aggregation decreased on both the fattier fish diets compared to the low fat fish (sole). Similar results were demonstrated for TXB₂: the fattier fish produced statistically equivalent decreases (p = 0.06) among the diets, and lowered TXB₂ compared to the prefish diet. There were no significant differences among the diets for either systolic or diastolic BP though there was a significant decrease (p = 0.01) in diastolic pressure compared to the prefish diet when the salmon diet was consumed. Platelet fatty acid profiles reflected diet composition. / Graduation date: 1993

Graduation date: 2006

Diferents estudis assenyalen que el consum de peix, a través dels àcids grassos poliinsaturats omega-3 (AGPI omega-3), pot prevenir malalties vasculars lligades a l'aterosclerosi. Els AGPI omega -3 són altament insaturats, la qual cosa els fa especialment susceptibles a l'atac oxidatiu. Com que la lipoperoxidació de les lipoproteïnes de baixa densitat (LDL) és un dels esdeveniments clau en les etapes inicials de la formació de la placa d'ateroma, això faria d'una suplementació amb oli de peix de la dieta un factor potencialment pro-aterogènic. Així doncs, hi ha d'haver altres mecanismes que contrarestin l'efecte pro-oxidant dels AGPI omega-3 i que expliquin les seves propietats antiaterogèniques. A partir dels AGPI omega-6 i omega-3, se sintetitzen dues sèries diferents d'eicosanoids. Generalment, els primers presenten una activitat biològica més gran que els segons. Les dues sèries d'eicosanoids constitueixen un element clau en les accions diferenciades dels AGPI omega-3 respecte dels AGPI omega -6. Entre les accions del AGPI omega -3, i pel que fa a l'aterogènesi, hipotetitzem la modulació de la producció de radicals lliures com l'òxid nítric (·NO), sintetitzat per l'enzim eNOS en l'endoteli vascular, i d'efecte relaxador, i l'anió superòxid, d'efecte vasoconstrictor.Per tal d'estudiar els efectes d'una suplementació amb AGPI omega-6 i amb AGPI omega -3 en vasos i en lipoproteïnes, s'alimentaren rates Sprague-Dawley, amb una dieta rica o bé en oli de blat de moro (5%, ric en AGPI omega -6), o bé en oli de peix (5%, ric en AGPI omega-3) durant 8 setmanes. Part dels animals, a més, reberen una suplementació addicional de L-arginina lliure, substrat de l'eNOS. Després del període d'alimentació, els animals eren sacrificats i se n'extreia l'aorta (per fer estudis vasculars) i la sang (per obtenir-ne les lipoproteïnes de molt baixa densitat (VLDL) i les LDL).Els estudis en bany d'òrgans van permetre d'observar un augment en la relaxació induïda per acetilcolina i mediada per ·NO en les rates suplementades amb oli de peix. L'augment d'aquestes relaxacions no era degut ni a una menor producció de superòxid (O2·-, principal agent limitador de la biodisponibilitat vascular de ·NO), ni a una major resposta del vas al ·NO (no hi havia diferències en les relaxacions induïdes per nitroprussiat sòdic, un donador de ·NO).D'altra banda, també augmentava, en les rates suplementades amb oli de peix, la producció basal de ·NO (avaluada per ressonància de spin electrònic), fenomen vinculat, a més, a l'estimulació de l'expressió del ARNm i de la proteïna d'eNOS. Això s'acompanyava d'una davallada del contingut de L-arginina lliure del teixit i d'un augment del GMPc. Quant a la suplementació de L-arginina en les dietes, aquesta produïa també un augment, en tots dos tipus d'olis, de la producció vascular de ·NO.Pel que fa a la fracció de VLDL+LDL, no s'hi observaven canvis deguts a la dieta en la mobilitat electroforètica, que és un indicador del grau d'oxidació nadiu d'aquestes. En canvi, la suplementació amb oli de peix davallava les reserves d'alfa-tocoferol de les lipoproteïnes. En consonància amb això, davant un atac oxidatiu ex vivo induït per Cu2+, les lipoproteïnes de les rates suplementades amb oli de peix, iniciaven l'oxidació abans, però alhora s'hi propagava menys ràpidament i el nivell màxim de diens conjugats era més baix.L'augment de la producció vascular de ·NO generat per la suplementació amb oli de peix, és un mecanisme potencialment antiaterogènic, a través del manteniment del to vascular mitjançant l'activitat vasorelaxadora del ·NO. A banda d'això, el ·NO, d'acord amb diversos estudis in vitro, actua com a antioxidant en lipoproteïnes que podria interferir en la propagació de l'oxidació in vivo i explicar la paradoxa de l'oli de peix en la prevenció de l'aterosclerosi.

[Truncated abstract] Increased incidence of hypertension, insulin resistance, obesity and dyslipidemia, collectively referred to as the metabolic syndrome, has been linked to low birth weight, an indicator of a poor fetal environment. This association reflects developmental programming, a process by which organ systems are affected during early development such that disease states are more likely to emerge in adult life. Fetal glucocorticoid overexposure is thought to be a key factor that mediates developmental programming. Accordingly, maternal treatment with the synthetic glucocorticoid dexamethasone retards fetal growth and leads to delayed puberty, hypertension, hyperinsulinemia, and hyperleptinemia, either with or without increased adiposity, in adult offspring. Importantly, the postnatal environment can either amplify or attenuate the long-term outcome of developmental programming. The focus of this thesis was whether adverse developmental programming outcomes can be attenuated by the postnatal environment and thus provide therapeutic potential. Specifically, the effects of a postnatal diet rich in omega-3 fatty acids on glucocorticoid-induced developmental programming outcomes was investigated. ... The adipocyte phenotype was examined in Study 6, with hyperleptinaemia evident in offspring at 6 and 12 months of age in dexamethasone-exposed animals on a standard omega-3 diet, but this effect was prevented by a high omega-3 diet. The pattern of plasma leptin was paralleled by changes in leptin mRNA in retroperitoneal fat. Similarly, plasma levels of the inflammatory markers IL-6 and IL-1β were upregulated by prenatal glucocorticoid exposure and these were attenuated by postnatal dietary omega-3 fatty acids. Overall, omega-3 ingestion reduced adiposity, as indicated by measures of body composition. In conclusion, the studies presented in this thesis demonstrate for the first time that many of the detrimental effects of excess glucocorticoid exposure in utero on the adult phenotype can be attenuated by a postnatal diet rich in omega-3 fatty acids. This beneficial effect of omega-3 fatty acids was associated with a reversal of some (e.g. adiposal leptin) but not all (e.g. renal GR) 'programmed' changes in gene expression. These findings raise the possibility that dietary supplementation with omega-3 fatty acids may provide a viable therapeutic option for preventing and/or reducing adverse programming outcomes in humans.