Master of Science / Department of Grain Science and Industry / Greg Aldrich / Since 2010, there have been seven recalls related to thiamine deficiency in cat food products (FDA, 2017; FSA, 2017). Cats have a high requirement of thiamine (5.6 mg/kg), and deficiencies can lead to death within a month if not treated (AAFCO, 2017). A few studies have been published regarding the impact of retort processing on thiamine loss in canned pet food but no work has been reported on heat penetration in other containers (pouches and trays). Therefore, our objectives were to determine the effect of container size and type on thiamine retention during processing of cat food. Our hypothesis was that thiamine retention would be impacted by container size and type. To address this, a 2x3 factorial arrangement of treatments in which two container sizes (small: 89-104 mL vs medium: 163-207 mL) and three container types (can, pouch, and tray) were evaluated for B-vitamin losses and thermal process lethality of a wet pet food. A model wet cat loaf type formula was produced for all six experimental treatments and each was processed in duplicate over six-days. All ingredients including the vitamin premix (10x level) were thoroughly mixed, heated to 43ºC, and containers were manually filled. The filled and sealed containers were cooked in a retort (cans: SJ Reid Retort, Bellingham, WA; trays and pouches: FMC retort, Madera, CA) with thermocouples attached to the center of representative containers (n=14) in each batch. Software (Calsoft Systems, v. 5.0.5) was used to record the internal temperatures. The retort time was targeted to meet an F₀=8 at 121ºC and 21 PSI. Treatment sample were analyzed for included pH, moisture, crude protein, crude fat, ash, and B-vitamins. Results were analyzed using the GLM procedure in SAS (v. 9.4; Cary, NC) with means and interactions separated using Fisher LSD method by significant F and an α of 5%. The proximate composition and pH were similar (P > 0.10) among treatments. There was an interaction (P < 0.05) between container size and type for time to reach the F₀=8; wherein, the medium can and tray had the longest time (45.5 and 46.3 min, respectively); the small can and tray, and medium pouch were intermediate (35.4, 36.0, and 32.0 min, respectively); and the small pouch had the shortest time (36.0 min). There was no difference for either main effect of container type or size on heating lethality values (each main effect average F₀=10.3) and total lethality ranged from 12.7-16.7 min. Thiamine retention was lowest (70%) among the B-vitamins, and there was minimal loss throughout the process. The excess heating beyond F₀=8 may account for the dramatic impact on the retention of heat labile nutrients like thiamine. This may be more difficult to control in the newer packaging systems like pouches and trays.

Dentre os diversos fatores responsáveis pela instabilidade química das vitaminas nos alimentos, a exposição à radiação luminosa é determinante, principalmente em alimentos contendo vitamina B2. O presente trabalho investigou a degradação fotossensibilizada das vitaminas do complexo B (ácido fólico, piridoxal, biotina e niacina) por flavinas. O piridoxal-5\'-fosfato (PLP) mostrou-se reativo frente aos estados singleto e tripleto excitado das flavinas com constante de desativação de 1,03 1011 L mol-1 s-1 para o estado singleto, valor este superior ao valor esperado para reações bimoleculares controladas por difusão em meio aquoso. Foi observada uma dependência significativa da constante de velocidade de desativação do estado singleto excitado com a temperatura, onde o aumento da temperatura proporciona um decréscimo da constante de velocidade sugerindo a existência de um complexo [FMN...PLP] no estado fundamental o qual foi confirmado por espectroscopia de fluorescência resolvida no tempo. O PLP mostrou-se reativo frente ao estado tripleto excitado da FMN com constante de velocidade de 3kq = 3,0 108 L mol-1 s-1 em meio de tampão fosfato pH 6,4 ou em meio de óxido de deutério a 25 &deg;C. Não foi observada diferença significativa entre as constantes de desativação do estado tripleto excitado em meio aquoso e de óxido de deutério o que corrobora com um processo direto de transferência de elétrons do PLP para a 3FMN* ao invés de um processo de transferência de átomo de hidrogênio. As vitaminas (biotina e niacina) mostraram-se não reativas frente aos estados singleto e tripleto excitados da vitamina B2 o que pode ser atribuído aos altos potenciais de oxidação, Eo > 2 V vs. NHE, observados para estas vitaminas em meio aquoso. A voltametria cíclica do PLP apresentou um processo anódico e irreversível (E= 1,07 V vs. NHE), controlada cineticamente por transferência de elétrons heterogênea do PLP para o eletrodo. O rendimento quântico de fotodegradação do PLP em meio aquoso e aerado é 2,5 vezes superior ao encontrado para a reação em meio anaeróbico, o que sugere a participação do íon superóxido no processo global de degradação do PLP. O ácido fólico demonstrou-se igualmente reativo frente ao estado tripleto excitado das flavinas (3kq= 4,8 108 L&middot;mol-1 s-1 e &Phi; = 0,26 (meio aerado) e &Phi; = 0,32 (meio anaeróbico)) e a sua complexação pela &beta;-LG (&Phi; = 0,032 (meio aerado) e &Phi; = 0,055 (meio anaeróbico)) uma eficiente abordagem na proteção desta vitamina frente a fotodegradação sensibilizada por flavinas. / Among several factors responsible for the chemical instability of vitamins in food, exposure to light radiation is decisive, especially in supplemented or fortified food with vitamin B2. This study investigated the photosensitized degradation of B-vitamins (folic acid, pyridoxal, biotin and niacin) by flavins. The pyridoxal-5\'-phosphate (PLP) reacted with singlet and triplet excited states of flavins with rate constant for quenching of 1kq = 1,03 1011 L mol-1 s-1 for the singlet state, this value is higher than expected value of bimolecular reactions controlled by diffusion in an aqueous solvent. A significant dependence was observed for the rate constant for deactivation of singlet excited state with temperature, the increase of the temperature leads to a decrease of the rate constant suggesting the existence of a complex [FMN...PLP] in ground state confirmed by time resolved fluorescence spectroscopy. PLP reacted with FMN triplet excited state with rate constant 3kq = 2,96 108 L mol-1 s-1 in phosphate buffer pH 6,4 or deuterium oxide at 25 &deg;C. There was no significant difference between the rate constant of deactivation of the triplet-excited of FMN in aqueous solution or deuterium oxide which confirms a direct process of electron transfer to PLP for 3FMN* rather than a process of transfer of hydrogen atom. Biotin and niacin unreacted with singlet and triplet excited states of vitamin B2 which can be attributed to high oxidation potentials, Eo > 2 V vs. NHE, observed for this vitamins in aqueous solution. The cyclic voltammetry of PLP had an irreversible anodic oxidation process (E = 1.07 V vs. NHE) kinetically controlled by heterogeneous electron transfer from PLP to the electrode. The quantum yield of photodegradation of PLP in aerobic condition is 2.5 times higher than that found for the reaction in anaerobic condition, which suggests the of participation of superoxide ion in the PLP global degradation process. Folic acid demonstrated reactive with triplet excited state of flavins (3kq= 4,8 108 L&middot;mol-1 s-1 and &Phi; = 0,26 (aerobic condition) and &Phi; = 0,32 (anaerobic condition)) and the complexation with &beta;-LG (&Phi; = 0,032 (aerobic condition) and &Phi; = 0,055 anaerobic condition)) an efficient approach in protecting the vitamin against photodegradation sensitized by flavins.

Recent epidemiological evidence suggests that many chronic health disorders in the developed world are associated with endogenous toxins formed from the Western diet. The Western diet, which encompasses calorie dense foods, processed foods and increased quantities of red meat, can cause intracellular oxidative stress through increased formation of reactive oxygen species(ROS) and reactive carbonyl species (RCS). A number of micronutrients have been investigated for their protective capacity in in vitro and in vivo models of oxidative stress. This thesis investigated the cytotoxic targets of Fenton-mediated ROS and RCS and the subsequent protective mechanisms of vitamins B1 (thiamin) or B6 (pyridoxal, pyridoxamine or pyridoxine) in an isolated rat hepatocyte model. The approach was to use an “accelerated cytotoxicity mechanism screening” technique (ACMS) to develop an in vitro cell system that mimicked in vivo tissue cytotoxicity. Using this technique, we investigated the protective mechanisms of vitamins B1 and/or B6 against the cytotoxic effects of two endogenous toxins associated with the Western diet: 1) RCS, as exemplified by glyoxal, a glucose/fructose autoxidation product and 2) biological ROS induced by exogenous iron. Firstly, we developed an understanding of the sequence of events contributing to glyoxal-induced oxidative stress, with a focus on protein carbonylation. Next, we determined the mechanisms by which carbonyl scavenging drugs (vitamin B6 included) protected against the intracellular targets of glyoxal-induced toxicity. Our results suggested that the agents used were cytoprotective by multiple mechanisms and glyoxal trapping was only observed when the agents were administered at concentrations equal to glyoxal. We also evaluated the protective capacity of vitamins B1 and B6 against iron-catalyzed cytotoxicity and found that hepatocytes could be rescued from protein and DNA damage when vitamins B1 or B6 were added up to one hour after treatment with iron. The vitamins also varied in their primary mechanisms of protection. Our improved understanding of Western diet-derived endogenous toxins enabled us to identify and prioritize the specific inhibitory mechanisms of vitamins B1 or B6. The ability to delay, inhibit or reverse toxicity using multi-functional B1 or B6 vitamins could prove useful as therapy to minimize oxidative stress in diet-induced chronic conditions.

Recent epidemiological evidence suggests that many chronic health disorders in the developed world are associated with endogenous toxins formed from the Western diet. The Western diet, which encompasses calorie dense foods, processed foods and increased quantities of red meat, can cause intracellular oxidative stress through increased formation of reactive oxygen species(ROS) and reactive carbonyl species (RCS). A number of micronutrients have been investigated for their protective capacity in in vitro and in vivo models of oxidative stress. This thesis investigated the cytotoxic targets of Fenton-mediated ROS and RCS and the subsequent protective mechanisms of vitamins B1 (thiamin) or B6 (pyridoxal, pyridoxamine or pyridoxine) in an isolated rat hepatocyte model. The approach was to use an “accelerated cytotoxicity mechanism screening” technique (ACMS) to develop an in vitro cell system that mimicked in vivo tissue cytotoxicity. Using this technique, we investigated the protective mechanisms of vitamins B1 and/or B6 against the cytotoxic effects of two endogenous toxins associated with the Western diet: 1) RCS, as exemplified by glyoxal, a glucose/fructose autoxidation product and 2) biological ROS induced by exogenous iron. Firstly, we developed an understanding of the sequence of events contributing to glyoxal-induced oxidative stress, with a focus on protein carbonylation. Next, we determined the mechanisms by which carbonyl scavenging drugs (vitamin B6 included) protected against the intracellular targets of glyoxal-induced toxicity. Our results suggested that the agents used were cytoprotective by multiple mechanisms and glyoxal trapping was only observed when the agents were administered at concentrations equal to glyoxal. We also evaluated the protective capacity of vitamins B1 and B6 against iron-catalyzed cytotoxicity and found that hepatocytes could be rescued from protein and DNA damage when vitamins B1 or B6 were added up to one hour after treatment with iron. The vitamins also varied in their primary mechanisms of protection. Our improved understanding of Western diet-derived endogenous toxins enabled us to identify and prioritize the specific inhibitory mechanisms of vitamins B1 or B6. The ability to delay, inhibit or reverse toxicity using multi-functional B1 or B6 vitamins could prove useful as therapy to minimize oxidative stress in diet-induced chronic conditions.

Dentre os diversos fatores responsáveis pela instabilidade química das vitaminas nos alimentos, a exposição à radiação luminosa é determinante, principalmente em alimentos contendo vitamina B2. O presente trabalho investigou a degradação fotossensibilizada das vitaminas do complexo B (ácido fólico, piridoxal, biotina e niacina) por flavinas. O piridoxal-5\'-fosfato (PLP) mostrou-se reativo frente aos estados singleto e tripleto excitado das flavinas com constante de desativação de 1,03 1011 L mol-1 s-1 para o estado singleto, valor este superior ao valor esperado para reações bimoleculares controladas por difusão em meio aquoso. Foi observada uma dependência significativa da constante de velocidade de desativação do estado singleto excitado com a temperatura, onde o aumento da temperatura proporciona um decréscimo da constante de velocidade sugerindo a existência de um complexo [FMN...PLP] no estado fundamental o qual foi confirmado por espectroscopia de fluorescência resolvida no tempo. O PLP mostrou-se reativo frente ao estado tripleto excitado da FMN com constante de velocidade de 3kq = 3,0 108 L mol-1 s-1 em meio de tampão fosfato pH 6,4 ou em meio de óxido de deutério a 25 &deg;C. Não foi observada diferença significativa entre as constantes de desativação do estado tripleto excitado em meio aquoso e de óxido de deutério o que corrobora com um processo direto de transferência de elétrons do PLP para a 3FMN* ao invés de um processo de transferência de átomo de hidrogênio. As vitaminas (biotina e niacina) mostraram-se não reativas frente aos estados singleto e tripleto excitados da vitamina B2 o que pode ser atribuído aos altos potenciais de oxidação, Eo > 2 V vs. NHE, observados para estas vitaminas em meio aquoso. A voltametria cíclica do PLP apresentou um processo anódico e irreversível (E= 1,07 V vs. NHE), controlada cineticamente por transferência de elétrons heterogênea do PLP para o eletrodo. O rendimento quântico de fotodegradação do PLP em meio aquoso e aerado é 2,5 vezes superior ao encontrado para a reação em meio anaeróbico, o que sugere a participação do íon superóxido no processo global de degradação do PLP. O ácido fólico demonstrou-se igualmente reativo frente ao estado tripleto excitado das flavinas (3kq= 4,8 108 L&middot;mol-1 s-1 e &Phi; = 0,26 (meio aerado) e &Phi; = 0,32 (meio anaeróbico)) e a sua complexação pela &beta;-LG (&Phi; = 0,032 (meio aerado) e &Phi; = 0,055 (meio anaeróbico)) uma eficiente abordagem na proteção desta vitamina frente a fotodegradação sensibilizada por flavinas. / Among several factors responsible for the chemical instability of vitamins in food, exposure to light radiation is decisive, especially in supplemented or fortified food with vitamin B2. This study investigated the photosensitized degradation of B-vitamins (folic acid, pyridoxal, biotin and niacin) by flavins. The pyridoxal-5\'-phosphate (PLP) reacted with singlet and triplet excited states of flavins with rate constant for quenching of 1kq = 1,03 1011 L mol-1 s-1 for the singlet state, this value is higher than expected value of bimolecular reactions controlled by diffusion in an aqueous solvent. A significant dependence was observed for the rate constant for deactivation of singlet excited state with temperature, the increase of the temperature leads to a decrease of the rate constant suggesting the existence of a complex [FMN...PLP] in ground state confirmed by time resolved fluorescence spectroscopy. PLP reacted with FMN triplet excited state with rate constant 3kq = 2,96 108 L mol-1 s-1 in phosphate buffer pH 6,4 or deuterium oxide at 25 &deg;C. There was no significant difference between the rate constant of deactivation of the triplet-excited of FMN in aqueous solution or deuterium oxide which confirms a direct process of electron transfer to PLP for 3FMN* rather than a process of transfer of hydrogen atom. Biotin and niacin unreacted with singlet and triplet excited states of vitamin B2 which can be attributed to high oxidation potentials, Eo > 2 V vs. NHE, observed for this vitamins in aqueous solution. The cyclic voltammetry of PLP had an irreversible anodic oxidation process (E = 1.07 V vs. NHE) kinetically controlled by heterogeneous electron transfer from PLP to the electrode. The quantum yield of photodegradation of PLP in aerobic condition is 2.5 times higher than that found for the reaction in anaerobic condition, which suggests the of participation of superoxide ion in the PLP global degradation process. Folic acid demonstrated reactive with triplet excited state of flavins (3kq= 4,8 108 L&middot;mol-1 s-1 and &Phi; = 0,26 (aerobic condition) and &Phi; = 0,32 (anaerobic condition)) and the complexation with &beta;-LG (&Phi; = 0,032 (aerobic condition) and &Phi; = 0,055 anaerobic condition)) an efficient approach in protecting the vitamin against photodegradation sensitized by flavins.

Introdução: Fatores de risco para doenças cardiovasculares (DCV) tornaram-se prevalentes em crianças e adolescentes. Ácidos graxos (AGs) ?3 auxiliam na prevenção de DCV, porém seu consumo alimentar na infância é reduzido. Há a hipótese de que as vitaminas B2, B6, B12 e folato possam contribuir para o aumento da concentração de ácidos graxos poli-insaturados (PUFAs) no plasma e nos eritrócitos, além de reduzir os níveis de homocisteína total (tHcy), e auxiliar na prevenção de DCV. Por essa razão, o presente estudo teve como objetivo verificar a associação entre perfil lipídico, perfil de ácidos graxos, homocisteína e biomarcadores para vitaminas do complexo B em crianças e adolescentes. Métodos: Este estudo transversal incluiu 249 crianças e adolescentes entre 9 e 13 anos de idade. O consumo alimentar foi avaliado por meio do questionário de frequência alimentar, recordatório de 24 horas e índice de qualidade da dieta (IQD). O perfil lipídico e os biomarcadores para vitaminas B2, B6, B12 e ácido fólico foram dosados no plasma. O perfil de AGs e os metabólitos do ciclo da homocisteína (metionina, SAM, SAH, tHcy, cistationina e cisteína) foram dosados nas células vermelhas do sangue. As associações foram testadas com modelos de regressão linear múltiplos, ajustados para sexo, estadiamento puberal, índice de massa corporal e IQD. Resultados: Não houve associação entre as vitaminas do complexo B e baixos níveis de colesterol total, triglicérides e LDL-c. Porém, houve associação positiva entre os níveis séricos de vitamina B2 e folato plasmático com PUFAs ?3 e ?6. O aumento de 1 nmol/L de vitamina B2 esteve associado ao aumento de 0,19 mg/dL de EPA e 0,21 mg/dL de ARA e DHA (p<0,01). O aumento de 1 ng/mL de folato plasmático esteve associado ao aumento de 0,14 mg/dL de EPA (p<0,05), 0,22 mg/dL de ARA e 0,17 mg/dL de DHA (p<0,01). Estas vitaminas não estiveram associadas à redução dos níveis de tHcy (p>0,05). As vitaminas B6 e B12 estiveram associadas à redução dos níveis de tHcy (p<0,01), mas não se associaram a maiores níveis de PUFAs (p>0,05). Houve associação negativa entre os níveis séricos de vitamina B6 com PUFAs ?3 e ?6. O aumento de 1 nmol/L de vitamina B6 esteve associado à redução de 0,15 mg/dL de ARA e 0,14 mg/dL de DHA (p<0,05). Os níveis de tHcy foram associados positivamente com os níveis de PUFAs (p<0,01). Conclusão: Maiores concentrações plasmáticas de vitamina B2 e folato estão associadas a maiores níveis deResumo PUFAs ?3 e ?6 nos eritrócitos. A via metabólica mais provável para explicar tais associações é o metabolismo de um-carbono, apesar destas vitaminas não terem se associado a menores níveis de tHcy. Estes dados sugerem que níveis plasmáticos adequados de vitamina B2 e folato podem melhorar o perfil de AGs circulantes. O equilíbrio nas concentrações séricas de AGs ?3 e ?6 contribui para o desenvolvimento do sistema nervoso central na infância e para a prevenção de DCV, cada vez mais comuns em decorrência do sedentarismo, má alimentação e excesso de gordura corporal, em crianças e adolescentes. / Introduction: Risk factors for cardiovascular disease (CVD) have become prevalent in children and adolescents. Fatty acids (FA) ?3 help prevent CVD, but the intake of food sources of this FA during childhood is reduced. It is hypothesized that vitamins B2, B6, B12 and folate may contribute to the increased concentration of polyunsaturated fatty acids (PUFAs) in plasma and in erythrocytes, in addition to reducing total homocysteine levels (tHcy), and assisting in the prevention of CVD. For this reason, the present study aimed to verify the association between lipid profile, fatty acid profile, homocysteine and B-vitamins biomarkers in children and adolescents. Methods: This cross-sectional study included 249 children and adolescents, aged 9 to 13 years old. Dietary intake was assessed by the food frequency questionnaire, 24-hour recall, and healthy eating index (HEI). The lipid profile and biomarkers for vitamins B2, B6, B12 and folate were measured in plasma. The FA profile and metabolites from homocysteine cycle (methionine, SAM, SAH, tHcy, cystathionine and cysteine) were measured in red blood cells. The associations were tested with multiple linear regression models, adjusted for sex, pubertal status, body mass index and HEI. Results: There was no association between B vitamins and low levels of total cholesterol, triglycerides and LDL-c. However, there was a positive association between serum levels of vitamin B2 and plasma folate with PUFAs ?3 and ?6. An increase of 1 nmol/L in vitamin B2 was associated with an increase of 0.19 mg/dL of EPA and 0.21 mg/dL of ARA and DHA (p<0.01). An increase of 1 ng/mL in plasma folate was associated with an increase of 0.14 mg/dL of EPA (p<0.05), 0.22 mg/dL of ARA and 0.17 mg/dL of DHA (p<0.01). These vitamins were not associated with reduced tHcy levels (p>0.05). Vitamins B6 and B12 were associated with reduced tHcy levels (p <0.01), but were not associated with higher levels of PUFAs (p> 0.05). There was a negative association between serum levels of vitamin B6 with PUFAs ?3 and ?6. The increase of 1 nmol/L in vitamin B6 was associated with a reduction of 0.15 mg/dL of ARA and 0.14 mg/dL of DHA (p <0.05). Homocysteine levels were positively associated with PUFA levels (p <0.01). Conclusion: Higher plasma concentrations of vitamin B2 and folate are associated with higher levels of PUFAs ?3 and ?6 in erythrocytes. The most likely metabolic pathway to explain such associations is the one-carbon metabolism, although these vitamins have not been associated with lower tHcy levels. These data suggest that adequate plasma levels of vitamin B2 and folate may improve the profile of circulating FA. TheAbstract balance in the serum concentrations of FA ?3 and ?6 contributes to the development of the central nervous system in childhood and to the prevention of CVD, increasingly common due to sedentary lifestyle, poor diet and excess body fat, in children and adolescents.

This study involves data from the Cache County Study, which began in 1994 with joined efforts by Duke University, Utah State University, and Johns Hopkins University. It consisted of 5,092 participants from Cache County, Utah, located in the northern part of the state. Characteristics of the population include high participation rates (~ 90%), a majority of participants are members of The Church of Jesus Christ of Latter-day Saints, longer life expectancy than the general US population, a greater than 80% rate of at least a high school education, and low rates of migration. Subjects cognitive status was screened using the Modified Mini-Mental State Examination or rated by knowledgeable informants using an Informant Questionnaire for Cognitive Decline. Low scoring subjects were examined using the Dementia Questionnaire, an inventory of cognitive symptoms, functional impairments, and medical conditions relevant to dementia. The clinical data were reviewed by a geropsychiatrist and neuropsychologist. Those suspected of dementia underwent further testing and final dementia diagnoses were decided by a consensus conference of experts. Clinical assessment at the baseline interview identified 368 individuals out of the original 5,092 subjects as having dementia. These individuals were removed from the present analysis. Prevalent cases of dementia were excluded in our analyses of risk associated with incident AD. Dietary data were collected using a food frequency questionnaire at baseline in 1995. A list of 142 foods was provided and participants noted frequency they consume the food or food group. To calculate intake of a specific nutrient, the nutrient content of each food is multiplied by the frequency of consumption for each food. This number is summed over all food items. Cox Proportional hazards modeling was used to assess risk of incident AD in relationship to folate and B-vitamin intake over eleven subsequent years of data collection. Cox modeling assists in analysis of censored cases (drop-outs and deaths). No relationship was found between folate from food, supplement, or combined sources with dementia or with AD. Similar results were observed for B-12 and B-6.

Master of Science / Department of Grain Science and Industry / Greg Aldrich / Water soluble B-vitamins play an integral role in normal metabolic function in cats. For example, thiamine deficiency results in anorexia, neurological impairment, and, in severe cases, death in a few weeks’ time. However, little research has addressed how these vitamins are affected during cat food canning. Thiamine is the most susceptible to degradation during this process, with less known about how it affects the other B-vitamins. Therefore, our objectives were to determine the effects of modifying processing parameters on thiamine and other water-soluble B-vitamins in a model canned cat food. In a series of five experiments, various processing parameters were adjusted: including cook (retort) time, batter moisture and temperature, pH, protein source, and the addition of sulfites. Pressure (172368.93 Pa) and temperature (121 ̊C) within the retort remained the same for all treatments. As retort time increased, thiamine concentration decreased (P ≤ 0.05). No loss of B-vitamin concentration was noted for thiamine, riboflavin, cobalamin, and pantothenic acid as batter moisture increased. Likewise, as batter temperature increased, concentration of riboflavin, niacin, pyridoxine, folic acid, and pantothenic acid remained constant (P ˃ 0.10). When different types of thiamine were included for supplementation, thiamine mononitrate tended to have a greater retention of the vitamin than thiamine hydrochloride (P = 0.12). The protein sources selected for the experiment included chicken as a control, beef liver, chicken liver, pork liver, salmon, tuna, and whitefish. The salmon, tuna, and whitefish were grouped together for analysis. Beef liver, chicken liver, and pork liver were grouped together for analysis. The vitamin retention of each group was compared. When compared to chicken or liver, thiamine retention was greatest in diets containing fish (P≤ 0.05). In addition, riboflavin, niacin, and cobalamin retentions were greatest (P≤ 0.05) in diets containing liver. The addition of sulfites came from dehydrated potatoes added to thediets in exchange for rice. Thiamine tended to decrease in those diets with sulfite containing dehydrated potatoes (P= 0.07) compared to diets containing rice. Pyridoxine and pantothenic acid retention decreased in diets containing dehydrated potatoes (P≤ 0.05) compared to diets containing rice. The largest negative impact on thiamine retention was time in the retort; cobalamin, folic acid, and riboflavin were also negatively affected. Including sulfite-containing potatoes in the diet tended to decrease thiamine, pyridoxine, and pantothenic acid. It was expected that diets containing chicken would retain more thiamine than those formulated with fish and liver. However, diets containing fish retained more thiamine, pyridoxine, and pantothenic acid. Therefore, it appears that processing and diet composition can affect the B-vitamin content of canned cat foods and must be accounted for when producing commercial products.

Premenstrual syndrome (PMS) is characterized by the presence of physical and psychological symptoms restricted to the late luteal phase of the menstrual cycle and associated with substantial impairment in life activities. In the U.S. about 8 to 15% of women of reproductive age suffer from PMS. Many micronutrients are potentially involved in the development of this disorder due to their role in the synthesis of neurotransmitters and hormones or in their regulation, but few previous studies have evaluated the effects of micronutrients on PMS. The first study examined the association between B vitamin intakes, and PMS development among women participating in the Nurses' Health Study 2 (NHS2). We found that high thiamin and high riboflavin intake from food sources were associated with lower risk of PMS. There were not significant associations between niacin, vitamin B6, folate, and vitamin B12 dietary intake and incident PMS. Intakes of B vitamins from supplements were not associated with lower risk of PMS. The second study evaluated the association between selected mineral intakes and PMS development in the NHS2. In this study, high iron intakes were associated with lower risk of PMS. Although there was no association between zinc and PMS risk, high intake of zinc relative to copper was associated with lower risk of PMS. There were no associations between of magnesium, copper, and manganese intakes and PMS. We observed a significantly higher risk of PMS in women with high intakes of potassium from food sources. The third study focused on the association between dietary intakes of B vitamins, zinc, magnesium, iron, potassium, and sodium and some biomarkers and PMS prevalence among younger women. In this study, we found an association between zinc intake and lower prevalence of PMS. Each 1 mg/d increase in vitamin B6 from foods was associated with a lower PMS symptom score. Blood magnesium levels were higher in women with PMS compared to women without PMS. We observed that intakes of some micronutrients were associated with lower risk of PMS, but further studies should be conducted. This dissertation contributes to the research on modifiable risk factors for PMS.

Many insects form close relationships with microbial symbionts. Insect symbionts can provide novel phenotypes to their hosts, including influencing dietary breadth. In the polyphagous cowpea aphid, Aphis craccivora, the facultative symbiont Arsenophonus improves aphid performance on one host plant (locust), but decreases performance on other plants. The goal of my thesis was to investigate the mechanism by which Arsenophonus facilitates use of locust. First, I assembled an Aphis craccivora-Arsenophonus-Buchnera reference transcriptome to conduct RNAseq analysis, comparing gene expression in aphids feeding on locust and fava, with and without Arsenophonus infection. Overall, few transcripts were differentially expressed. However, genes that were differentially expressed mapped to a variety of processes, including metabolism of glucose, cytoskeleton regulation, cold and drought regulation, and B-vitamin synthesis. These results imply that Arsenophonus is producing B-vitamins, which might be deficient in locust. In a second set of experiments, I used qPCR to test whether symbiont function across host plants might be mediated by bacterial titer. I measured relative Arsenophonus abundance across plants, and found Arsenophonus titer was variable, but generally greater on locust than fava. In summary, my results suggest that Arsenophonus synthesis of B-vitamins should be further investigated and may be mediated by bacterial titer.