The purpose of this study was to compile practical feeding guidelines for donkeys in the UK. Current guidelines are to feed 0.75 of horse feeding recommendations on a body weight basis. However, the superior digestive efficiency of donkeys, compared to horses, may render the use of horse recommendations inappropriate. The formulation of guidelines specific to donkeys would enable owners to calculate their donkey‟s requirements with greater accuracy and prevent overfeeding. A postal survey, used to gain information on the body condition score of donkeys in the UK, and the husbandry and feeding practices used to manage them, indicated that approximately 24% of donkeys in the UK are overweight. Feeding practices indicated that although owners were aware of their donkey‟s requirement for fibrous forages, the practice of feeding unnecessary concentrates, chaffs and high energy forages, in addition to grazing, was the likely cause of donkeys becoming overweight. The finding that the majority (85 – 90%) of donkeys were kept as non-working companion animals also reduced the need for owners to feed higher energy foods to their donkeys. Results also suggested that owners were unsure of how to adjust their donkey‟s diet to account for seasonal changes in requirements and pasture availability, as most owners‟ adjusted grazing access, and not the feeding of supplementary feeds. From a study of dry matter (DM) and digestible energy (DE) intakes by 20 mature donkeys maintaining weight during each UK season, the maintenance DE requirements of donkeys were calculated. Results showed no effect of sex on DM or DE intake. Season significantly (P<0.001) affected DM and DE intakes, implying increased requirements in winter compared to spring, summer and autumn. Dry matter intakes (DMI) increased from 51g/kg BW0.75 in spring, summer and autumn to 66g/kg BW0.75 in winter. Digestible energy requirements increased from 0.32MJ/kg BW0.75 in spring, summer and autumn to 0.43MJ/kg BW0.75 in winter. Comparison of results with horse recommendations showed considerably reduced requirements by donkeys. Horse recommendations overestimated DE requirements in summer and winter by 82 and 30%, respectively, making horse recommendations unsuitable for calculating donkey energy requirements. Husbandry practices commonly used by owners to manage their donkeys grazing access (grazing time, grazing area, strip grazing), were assessed for their effect on DMI by grazing donkeys in summer and autumn, using n-alkanes. The effect of grazing time was assessed by restricting donkeys to 8, 12 or 23 hours grazing per day. Season significantly affected food intake with donkeys in the 8 and 23 hour grazing groups eating more during summer when pasture availability was greater. Donkeys responded to the poorer quality summer pasture by grazing more intensively but less selectively, increasing the rate at which food was consumed. Grazing time was only influential over grass intake in summer, when pasture was more abundant. Restricting donkeys to 12 hours or less grazing per day significantly (P<0.001) reduced their grass intake compared to that of donkeys with 23 hours access. When grazing sparse pastures (autumn), grazing time did not influence grass intake, indicating an effect of herbage mass on grazing behaviour. Herbage mass was the most influential factor over diet composition (percentage of grass and straw consumed) in a second grazing study assessing the affect of strip grazing and set stocking systems on intake by grazing donkeys during summer and autumn. Herbage mass per donkey was higher in the set stocking system during both seasons, resulting in higher grass intakes. Determining if either grazing system was more effective at regulating grass intake was prevented due to differences in pasture availability between study sites. It is concluded that donkeys have lower DMI and maintenance DE requirements than horses, requiring donkey feeding guidelines to be formulated. Excess body weight in donkeys is caused in part, by the feeding of energy dense feeds in addition to low energy forages. Most owners place little nutritional importance on pasture, despite its potential to provide a large percentage of daily DM, DE and nutrient intake. Therefore nutritional guidelines must include advice on how to manage access to grazing, and how to feed donkeys with access to pasture. Restricting grazing time to 8 hours a day did reduce grass intake by donkeys, but was only effective when grazing abundant pastures. Providing ad libitum straw to grazing donkeys allows them to satisfy their DM and dietary fibre requirements without consuming excess energy.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / A obesidade é um dos maiores problemas de saúde pública que cresce em todo o mundo, resultante de um desequilíbrio entre ingestão alimentar e gasto energético. O aumento da adiposidade leva ao desenvolvimento de alterações funcionais. Pode-se dizer que a obesidade é o principal fator de risco para o desenvolvimento de doenças crônicas de maior prevalência como dislipidemias, doenças cardiovasculares e diabetes do tipo 2, acarretando na redução da qualidade e expectativa de vida. A Grelina é um hormônio sintetizado pelo estômago, que atua em diferentes tecidos através de um receptor específico (GHS-R1a), incluindo hipotálamo e tecido adiposo. A grelina tem uma ação direta sobre a regulação hipotalâmica da ingestão alimentar, induzindo um efeito orexígeno. Por outro lado, a grelina também modula o armazenamento de energia nos adipócitos. Esta dupla ação sugere que este hormônio pode atuar como uma ligação entre o sistema nervoso central e mecanismos periféricos. Portanto, considerando que a hiperalimentação neonatal induz obesidade na idade adulta por mecanismos desconhecidos, neste estudo foram pesquisados os efeitos da hiperalimentação no início da vida sobre o desenvolvimento da obesidade e, em particular, a sinalização da grelina no tecido adiposo em ratos jovens e adultos. Foram utilizados camundongos Swiss hiperalimentados através do modelo de redução da ninhada. Para induzir a hiperalimentação as ninhadas foram reduzidas a 3 filhotes machos por lactante no 30 dia de vida pós-natal. As ninhadas controles foram ajustadas em 9 filhotes por lactante. Foram avaliados parâmetros antropométricos como: massa corporal e massa do tecido adiposo visceral. A glicemia de jejum foi avaliada utilizando glicosímetro e fitas teste. A análise do conteúdo das proteínas envolvidas na via de sinalização da grelina foram detectadas pelo método de Western Blotting. Os grupos controle (C) e hiperalimentado (H) foram estudados aos 21 e 180 dias de vida. Os dados demonstram que a hipernutrição no início da vida induz um aumento significativo no peso corporal dos camundongos jovens, começando aos 10 dias, e este aumento de peso persistiu até à idade adulta (180 dias de idade). A glicemia e o peso da gordura visceral foram significativamente maiores no grupo hiperalimentado aos 21 e 180 dias, quando comparado com o grupo controle. Os níveis plasmáticos de grelina acilada apresentaram uma redução de 70% nos animais jovens e 49% adultos obesos. Além disso, no tecido adiposo branco, observamos um maior conteúdo (242%) do receptor de grelina (GHSR1a) nos animais hiperalimentados com 21 dias, e este aumento foi associado à modulação positiva do conteúdo e fosforilação de proteínas envolvidas no estoque e utilização de energia celular, tais como AKT, PI3K, AMPK, GLUT-4, e CPT1. No entanto, ao chegar à idade adulta os animais hiperalimentados não apresentaram diferença significativa no conteúdo de GHS-R1a e das proteínas AKT, PI3K, AMPK, GLUT-4, e CPT1. O conteúdo de PPAR&#611; foi menor no grupo obeso aos 21e 180 dias. Basicamente, mostramos que o metabolismo do tecido adiposo está alterado na obesidade adquirida no início da vida e, provavelmente, devido a essa modificação, ocorre um novo padrão da via de sinalização da grelina. / Obesity is a major public health problem that is growing worldwide, due to an imbalance between food intake and energy expenditure is a major risk factor for the development of most prevalent chronic diseases as dyslipidemias, heart disease and type 2 diabetes, resulting in reduced quality and life expectancy. Ghrelin is a hormone synthesized by the stomach that acts in different tissues via a specific receptor (GHS-R1a), including hypothalamus and adipose tissue. For instance, recent reports have shown that ghrelin has a direct action on hypothalamic regulation of food intake mainly inducing an orexigenic effect. On the other hand, ghrelin also modulates energy stores and expenditure in the adipocytes. This dual action has suggested that this hormone may act as a link between the central nervous system and peripheral mechanisms. Furthermore, concerning nutritional disorders, it has been suggested that obesity may be considered an impairment of the above cited link. Therefore, considering that neonatal overfeeding induces obesity in adulthood by unknown mechanisms, in this study we examined the effects of early life overnutrition on the development of obesity and in particular on adipose tissue ghrelin signaling in young mice. Our data demonstrated that overnutrition during early life induces a significant increase in body weight of young mice, starting at 10 days, and this increase in weight persisted until adulthood (180 days of age). In these animals, blood glucose and visceral fat weight were found higher at 21 and 180 days when compared to the control group. Acylated ghrelin circulating levels were found lower in the young obese pups and adult obese mice. In addition, in white adipose tissue ghrelin receptor (GHS-R1a) expression increased and was associated to positive modulation of content and phosphorylation of proteins involved in cell energy store and use as AKT, PI3K, AMPK, GLUT-4, and CPT1. However adulthood overfeeding animals showed no significant difference in the content of GHS-R1a and protein AKT, PI3K, AMPK, GLUT-4, and CPT1. PPAR&#947; content decreased in obese group at 21 and 180 days. Basically, we showed that adipose tissue metabolism is altered in early life acquired obesity and probably due to such modification a new pattern of ghrelin signaling pathway takes place.

Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / O excesso ou a privação de nutrientes em períodos específicos do desenvolvimento, tais como a lactação, estimulam alterações no metabolismo celular, por exemplo. Estas modificações perpetuam-se ao longo da vida e em conseqüência tornam o organismo mais suscetível ao aparecimento de patologias na idade adulta (Programação Metabólica). Estudamos a influência da grelina na secreção de insulina em camundongos Swiss de 120 dias submetidos à hiperalimentação na lactação. Para induzir a hiperalimentação as ninhadas foram reduzidas a 3 filhotes machos por lactante no 3o dia de vida pós-natal. As ninhadas controle foram ajustadas para 9 filhotes machos por lactante. Na idade adulta os animais hiperalimentados (AH) exibiram em comparação aos animais controle (AC) um incremento de 20% no peso corporal, maior índice de Lee (1705,63 g/mm + 29,3 vs 1374,10 g/mm + 54,9; p< 0,001), elevação da gordura corporal (31,0% + 4,6 vs 21,5% + 3,6; p< 0,01), aumento da gordura retroperitoneal (0,79 g + 0,1 vs 0,44 g + 0,1; p< 0,001), hiperglicemia de jejum (151,83 mg/ dl + 8,3 vs 118,0 mg/ dl + 1,0; p< 0,001), hiperinsulinemia de jejum (54,06 UI/ml + 2,3 vs 19,28 UI/ml + 1,53; p< 0,001) e hipogrelinemia de jejum (98,64 pg/ml + 56,5 vs 201,14 pg/ml + 46,4; p< 0,05). Os AH apresentaram maior secreção de insulina in vitro em presença de glicose aos 10 minutos (209,66 UI/ml + 46,5; p< 0,05), 30 minutos (441,88 UI/ml + 30,2; p< 0,05) e 60 minutos (214,34 UI/ml + 29,8) em comparação aos AC, respectivamente 86,90 UI/ml + 9,5; 74,31 UI/ml + 7,7 vs 27,45 UI/ml + 6,1; p< 0,05. As ilhotas pancreáticas dos AH adultos demonstraram em relação aos AC diminuição do consumo de O2 (1,76 pmols O2/ s. ilhota-1 + 0,4 vs 4,85 pmols O2/ s. ilhota-1 + 1,5; p< 0,001) e elevação do conteúdo do receptor de grelina GHSR1A (3,05 % + 2,13 vs 0,95 % + 0,1; p< 0,05). A grelina acilada estimulou a secreção de insulina in vitro dos AC aos 30 minutos (controle com grelina: 208,50 UI/ml + 40,85 vs controle sem grelina: 74,31 UI/ml + 7,7; p< 0,05) e diminuiu a razão do controle respiratório (controle com grelina: 1,45 + 0,2 vs controle sem grelina: 2,51 + 0,7; p< 0,05). Nos AH, a grelina acilada elevou o conteúdo de GLUT2 nas ilhotas pancreáticas em relação aos AC (hiperalimentados com grelina: 2,07 % + 0,5 vs controle com grelina: 0,85 % + 0,4; p< 0,01); entretanto a grelina não foi capaz de estimular a secreção de insulina nestes animais. Concluímos que a hiperalimentação na lactação associou-se ao aumento da gordura corporal e elevou a secreção de insulina na fase tardia do desenvolvimento. A grelina acilada estimulou a secreção de insulina somente nos AC adultos. / Excess or lack of nutrients at specific times of development generates adaptive responses that can change the body causing the onset of chronic diseases in adulthood (Metabolic Programming). We studied the influence of the hormone ghrelin in insulin secretion of adult Swiss mice overfed during lactation. To induce early postnatal overnutrition, the litter size was reduced to 3 pups per litter at the 3rd day after birth. In the control group, the litter size was adjusted to 9 pups per litter. In adulthood, overfed group (OG) had an increase of 20% in body weight compared to control group (CG). OG had increased in Lee index (1705.63 g/mm + 29.3 vs 1374.10 g/mm + 54.9; p< 0.001), high body fat (31.0% + 4.6 vs 21.5% + 3.6; p< 0.01), and an elevated retroperitoneal fat (0.79 g + 0.1 vs 0.44 g + 0.1; p< 0.001), fasting hyperglycemia (151.83 mg/ dl + 8.3 vs 118.0 mg/ dl + 1.0; p< 0.001), high fasting insulinemia (54.06 UI/ml + 2.3 vs 19.28 UI/ml + 1.53; p< 0.001), and low fasting plasma ghrelin (98.64 pg/ml + 56.5 vs 201.14 pg/ml + 46.4; p< 0.05) compared to CG at 120 days. OG exhibited high insulin secretion in vitro at 10 minutes (209.66 UI/ml + 46.5), 30 minutes (441.88 UI/ml + 30.2), and 60 minutes (214.34 UI/ml + 29.8) compared to CG, respectively 86.90 UI/ml + 9.5; 74.31 UI/ml + 7.7 vs 27.45 UI/ml + 6.1; p< 0.05. Pancreatic islets from OG had a decrease of O2 consumption compared to CG (1.76 pmols O2/ s. islets-1 + 0.4 vs 4.85 pmols O2/ s. islets-1 + 1.5; p< 0.001) and an increased of GHSR1A content (3.05 % + 2.13 vs 0.95 % + 0.1; p< 0.05). Acylated ghrelin increased control groups insulin secretion in vitro at 30 minutes (CG with ghrelin: 208.50 UI/ml + 40.85 vs CG without ghrelin 74.31 UI/ml + 7,7; p< 0.05) and decreased the respiratory control ration (CG with ghrelin: 1.45 + 0.2 vs CG without ghrelin: 2.51 + 0.7; p< 0.05). Also acylated ghrelin increased the GLUT2 content of pancreatic islets from OG compared to CG, respectively 2.07 % + 0.5 vs 0.85 % + 0.4; p< 0.01; however acylated ghrelin was not able to stimulate insulin secretion in OG. We conclude that the overnutrition during lactation is associated with increased body fat percentage and changes in pancreatic &#946; cells in the late stage of development. Acylated ghrelin stimulated insulin secretion only in adult CG.

Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / O excesso ou a privação de nutrientes em períodos específicos do desenvolvimento, tais como a lactação, estimulam alterações no metabolismo celular, por exemplo. Estas modificações perpetuam-se ao longo da vida e em conseqüência tornam o organismo mais suscetível ao aparecimento de patologias na idade adulta (Programação Metabólica). Estudamos a influência da grelina na secreção de insulina em camundongos Swiss de 120 dias submetidos à hiperalimentação na lactação. Para induzir a hiperalimentação as ninhadas foram reduzidas a 3 filhotes machos por lactante no 3o dia de vida pós-natal. As ninhadas controle foram ajustadas para 9 filhotes machos por lactante. Na idade adulta os animais hiperalimentados (AH) exibiram em comparação aos animais controle (AC) um incremento de 20% no peso corporal, maior índice de Lee (1705,63 g/mm + 29,3 vs 1374,10 g/mm + 54,9; p< 0,001), elevação da gordura corporal (31,0% + 4,6 vs 21,5% + 3,6; p< 0,01), aumento da gordura retroperitoneal (0,79 g + 0,1 vs 0,44 g + 0,1; p< 0,001), hiperglicemia de jejum (151,83 mg/ dl + 8,3 vs 118,0 mg/ dl + 1,0; p< 0,001), hiperinsulinemia de jejum (54,06 UI/ml + 2,3 vs 19,28 UI/ml + 1,53; p< 0,001) e hipogrelinemia de jejum (98,64 pg/ml + 56,5 vs 201,14 pg/ml + 46,4; p< 0,05). Os AH apresentaram maior secreção de insulina in vitro em presença de glicose aos 10 minutos (209,66 UI/ml + 46,5; p< 0,05), 30 minutos (441,88 UI/ml + 30,2; p< 0,05) e 60 minutos (214,34 UI/ml + 29,8) em comparação aos AC, respectivamente 86,90 UI/ml + 9,5; 74,31 UI/ml + 7,7 vs 27,45 UI/ml + 6,1; p< 0,05. As ilhotas pancreáticas dos AH adultos demonstraram em relação aos AC diminuição do consumo de O2 (1,76 pmols O2/ s. ilhota-1 + 0,4 vs 4,85 pmols O2/ s. ilhota-1 + 1,5; p< 0,001) e elevação do conteúdo do receptor de grelina GHSR1A (3,05 % + 2,13 vs 0,95 % + 0,1; p< 0,05). A grelina acilada estimulou a secreção de insulina in vitro dos AC aos 30 minutos (controle com grelina: 208,50 UI/ml + 40,85 vs controle sem grelina: 74,31 UI/ml + 7,7; p< 0,05) e diminuiu a razão do controle respiratório (controle com grelina: 1,45 + 0,2 vs controle sem grelina: 2,51 + 0,7; p< 0,05). Nos AH, a grelina acilada elevou o conteúdo de GLUT2 nas ilhotas pancreáticas em relação aos AC (hiperalimentados com grelina: 2,07 % + 0,5 vs controle com grelina: 0,85 % + 0,4; p< 0,01); entretanto a grelina não foi capaz de estimular a secreção de insulina nestes animais. Concluímos que a hiperalimentação na lactação associou-se ao aumento da gordura corporal e elevou a secreção de insulina na fase tardia do desenvolvimento. A grelina acilada estimulou a secreção de insulina somente nos AC adultos. / Excess or lack of nutrients at specific times of development generates adaptive responses that can change the body causing the onset of chronic diseases in adulthood (Metabolic Programming). We studied the influence of the hormone ghrelin in insulin secretion of adult Swiss mice overfed during lactation. To induce early postnatal overnutrition, the litter size was reduced to 3 pups per litter at the 3rd day after birth. In the control group, the litter size was adjusted to 9 pups per litter. In adulthood, overfed group (OG) had an increase of 20% in body weight compared to control group (CG). OG had increased in Lee index (1705.63 g/mm + 29.3 vs 1374.10 g/mm + 54.9; p< 0.001), high body fat (31.0% + 4.6 vs 21.5% + 3.6; p< 0.01), and an elevated retroperitoneal fat (0.79 g + 0.1 vs 0.44 g + 0.1; p< 0.001), fasting hyperglycemia (151.83 mg/ dl + 8.3 vs 118.0 mg/ dl + 1.0; p< 0.001), high fasting insulinemia (54.06 UI/ml + 2.3 vs 19.28 UI/ml + 1.53; p< 0.001), and low fasting plasma ghrelin (98.64 pg/ml + 56.5 vs 201.14 pg/ml + 46.4; p< 0.05) compared to CG at 120 days. OG exhibited high insulin secretion in vitro at 10 minutes (209.66 UI/ml + 46.5), 30 minutes (441.88 UI/ml + 30.2), and 60 minutes (214.34 UI/ml + 29.8) compared to CG, respectively 86.90 UI/ml + 9.5; 74.31 UI/ml + 7.7 vs 27.45 UI/ml + 6.1; p< 0.05. Pancreatic islets from OG had a decrease of O2 consumption compared to CG (1.76 pmols O2/ s. islets-1 + 0.4 vs 4.85 pmols O2/ s. islets-1 + 1.5; p< 0.001) and an increased of GHSR1A content (3.05 % + 2.13 vs 0.95 % + 0.1; p< 0.05). Acylated ghrelin increased control groups insulin secretion in vitro at 30 minutes (CG with ghrelin: 208.50 UI/ml + 40.85 vs CG without ghrelin 74.31 UI/ml + 7,7; p< 0.05) and decreased the respiratory control ration (CG with ghrelin: 1.45 + 0.2 vs CG without ghrelin: 2.51 + 0.7; p< 0.05). Also acylated ghrelin increased the GLUT2 content of pancreatic islets from OG compared to CG, respectively 2.07 % + 0.5 vs 0.85 % + 0.4; p< 0.01; however acylated ghrelin was not able to stimulate insulin secretion in OG. We conclude that the overnutrition during lactation is associated with increased body fat percentage and changes in pancreatic &#946; cells in the late stage of development. Acylated ghrelin stimulated insulin secretion only in adult CG.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / A obesidade é um dos maiores problemas de saúde pública que cresce em todo o mundo, resultante de um desequilíbrio entre ingestão alimentar e gasto energético. O aumento da adiposidade leva ao desenvolvimento de alterações funcionais. Pode-se dizer que a obesidade é o principal fator de risco para o desenvolvimento de doenças crônicas de maior prevalência como dislipidemias, doenças cardiovasculares e diabetes do tipo 2, acarretando na redução da qualidade e expectativa de vida. A Grelina é um hormônio sintetizado pelo estômago, que atua em diferentes tecidos através de um receptor específico (GHS-R1a), incluindo hipotálamo e tecido adiposo. A grelina tem uma ação direta sobre a regulação hipotalâmica da ingestão alimentar, induzindo um efeito orexígeno. Por outro lado, a grelina também modula o armazenamento de energia nos adipócitos. Esta dupla ação sugere que este hormônio pode atuar como uma ligação entre o sistema nervoso central e mecanismos periféricos. Portanto, considerando que a hiperalimentação neonatal induz obesidade na idade adulta por mecanismos desconhecidos, neste estudo foram pesquisados os efeitos da hiperalimentação no início da vida sobre o desenvolvimento da obesidade e, em particular, a sinalização da grelina no tecido adiposo em ratos jovens e adultos. Foram utilizados camundongos Swiss hiperalimentados através do modelo de redução da ninhada. Para induzir a hiperalimentação as ninhadas foram reduzidas a 3 filhotes machos por lactante no 30 dia de vida pós-natal. As ninhadas controles foram ajustadas em 9 filhotes por lactante. Foram avaliados parâmetros antropométricos como: massa corporal e massa do tecido adiposo visceral. A glicemia de jejum foi avaliada utilizando glicosímetro e fitas teste. A análise do conteúdo das proteínas envolvidas na via de sinalização da grelina foram detectadas pelo método de Western Blotting. Os grupos controle (C) e hiperalimentado (H) foram estudados aos 21 e 180 dias de vida. Os dados demonstram que a hipernutrição no início da vida induz um aumento significativo no peso corporal dos camundongos jovens, começando aos 10 dias, e este aumento de peso persistiu até à idade adulta (180 dias de idade). A glicemia e o peso da gordura visceral foram significativamente maiores no grupo hiperalimentado aos 21 e 180 dias, quando comparado com o grupo controle. Os níveis plasmáticos de grelina acilada apresentaram uma redução de 70% nos animais jovens e 49% adultos obesos. Além disso, no tecido adiposo branco, observamos um maior conteúdo (242%) do receptor de grelina (GHSR1a) nos animais hiperalimentados com 21 dias, e este aumento foi associado à modulação positiva do conteúdo e fosforilação de proteínas envolvidas no estoque e utilização de energia celular, tais como AKT, PI3K, AMPK, GLUT-4, e CPT1. No entanto, ao chegar à idade adulta os animais hiperalimentados não apresentaram diferença significativa no conteúdo de GHS-R1a e das proteínas AKT, PI3K, AMPK, GLUT-4, e CPT1. O conteúdo de PPAR&#611; foi menor no grupo obeso aos 21e 180 dias. Basicamente, mostramos que o metabolismo do tecido adiposo está alterado na obesidade adquirida no início da vida e, provavelmente, devido a essa modificação, ocorre um novo padrão da via de sinalização da grelina. / Obesity is a major public health problem that is growing worldwide, due to an imbalance between food intake and energy expenditure is a major risk factor for the development of most prevalent chronic diseases as dyslipidemias, heart disease and type 2 diabetes, resulting in reduced quality and life expectancy. Ghrelin is a hormone synthesized by the stomach that acts in different tissues via a specific receptor (GHS-R1a), including hypothalamus and adipose tissue. For instance, recent reports have shown that ghrelin has a direct action on hypothalamic regulation of food intake mainly inducing an orexigenic effect. On the other hand, ghrelin also modulates energy stores and expenditure in the adipocytes. This dual action has suggested that this hormone may act as a link between the central nervous system and peripheral mechanisms. Furthermore, concerning nutritional disorders, it has been suggested that obesity may be considered an impairment of the above cited link. Therefore, considering that neonatal overfeeding induces obesity in adulthood by unknown mechanisms, in this study we examined the effects of early life overnutrition on the development of obesity and in particular on adipose tissue ghrelin signaling in young mice. Our data demonstrated that overnutrition during early life induces a significant increase in body weight of young mice, starting at 10 days, and this increase in weight persisted until adulthood (180 days of age). In these animals, blood glucose and visceral fat weight were found higher at 21 and 180 days when compared to the control group. Acylated ghrelin circulating levels were found lower in the young obese pups and adult obese mice. In addition, in white adipose tissue ghrelin receptor (GHS-R1a) expression increased and was associated to positive modulation of content and phosphorylation of proteins involved in cell energy store and use as AKT, PI3K, AMPK, GLUT-4, and CPT1. However adulthood overfeeding animals showed no significant difference in the content of GHS-R1a and protein AKT, PI3K, AMPK, GLUT-4, and CPT1. PPAR&#947; content decreased in obese group at 21 and 180 days. Basically, we showed that adipose tissue metabolism is altered in early life acquired obesity and probably due to such modification a new pattern of ghrelin signaling pathway takes place.

Obesity is associated with sympathetic neural activation and elevated blood pressure(1,2). However, it is unclear whether modest elevations in body weight are sufficient to induce increases sympathetic activity (3). Furthermore, there is a large amount of individual variability in the blood pressure response to weight change (4). The reason(s) for this inter-individual variability are still uncertain, but body fat distribution and cardiorespiratory fitness may play a role (5,6). To address these and other issues regarding the relation between adiposity, sympathetic neural activity and blood pressure, we first examined the effects of modest, diet-induced weight gain on muscle sympathetic nervous system activity (MSNA) in healthy, lean, normotensive individuals. We hypothesized that modest weight gain would increase MSNA in these individuals, and that this neural activation would be accompanied by increases in blood pressure. Concordant with this hypothesis, MSNA and resting blood pressure were significantly elevated following weight gain. The increase in MSNA was correlated with the magnitude of body weight and fat gain, but was not obviously related to increases in visceral fat. We next examined the ability of cardiorespiratory fitness (CRF) to modulate the weight gain-induced increase in blood pressure in the same cohort of young, nonobese and normotensive individuals. We hypothesized that the increase in blood pressure would be attenuated in individuals with higher- compared with lower CRF (HCRF and LCRF, respectively). Indeed, we found that HCRF experienced significantly smaller increases in resting and ambulatory blood pressure compared to LCRF. In the pooled sample, baseline fitness was inversely related to the changes in resting systolic and diastolic pressure, and this relation was not diminished after statistically controlling for changes in abdominal visceral fat. The results of the present investigation suggest that even modest weight gain increases sympathetic activity and blood pressure, which, if left untreated, may contribute to the development of hypertension and other cardiovascular disorders. Maintenance of higher levels of CRF during periods of weight gain may reduce cardiovascular disease risk by mitigating the increases in blood pressure. Collectively, these findings may have important implications for understanding the link between obesity and hypertension. References 1. Davy KP. The global epidemic of obesity: are we becoming more sympathetic? Curr Hypertens Rep. 2004;6:241-6. 2. Grassi G, Seravalle G, Cattaneo BM, et al. Sympathetic activation in obese normotensive subjects. Hypertension. 1995;25:560-3. 3. Huggett RJ, Scott EM, Gilbey SG, Bannister J, Mackintosh AF, Mary DA. Disparity of autonomic control in type 2 diabetes mellitus. Diabetologia. 2005;48:172-9. 4. Masuo K, Mikami H, Ogihara T, Tuck ML. Weight gain-induced blood pressure elevation. Hypertension. 2000;35:1135-40. 5. Hayashi T, Boyko EJ, Leonetti DL, et al. Visceral adiposity is an independent predictor of incident hypertension in Japanese Americans. Ann Intern Med. 2004;140:992-1000. 6. Barlow CE, LaMonte MJ, Fitzgerald SJ, Kampert JB, Perrin JL, Blair SN. Cardiorespiratory fitness is an independent predictor of hypertension incidence among initially normotensive healthy women. Am J Epidemiol. 2006;163:142-50. / Ph. D.

Background: An estimated 9.7% of U.S. infants and toddlers are considered overweight. Hispanic infants persistently show higher prevalence rates for being overweight compared to black and white infants. Little is known about factors promoting excessive infant weight gain in Latinos. Purpose: Primary aim of this study was to describe multidimensional factors and maternal feeding practices that may correlate with infant overfeeding in Latina mothers. A secondary aim was to determine whether there was an association between these factors and infant weight gain. Subjects: Sixty-two low-income immigrant Latina mothers and their infants ages 4-12 months receiving assistance through the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). Design: A descriptive correlational cross-sectional study. Methods: A native Spanish-speaking investigator who guided the participants through the options administered all the measures. Measures included: acculturation indicators; maternal feeding beliefs; maternal feeding practices; maternal knowledge and self-efficacy; food availability/insecurity indicators; infant’s temperament; infant’s 24-hour dietary recall; and infant’s height and weight measures. Univariate and multiple linear regressions were used to examine relationships. Results: Over 25% of infants were at >85th percentile for weight-for-length, and 21% were at > 98th percentile. Among infants at the >85th percentile for weight-for-length, 27% of the mothers wished their infants were heavier. Three-quarters of the participants were not currently breastfeeding their infants (74.2%). Healthier maternal feeding practices were inversely correlated with maternal age and the number of people living at home. Multiple regression results showed infant’s age and maternal education as significant positive predictors of less controlling maternal feeding practices. None of the analyzed factors were significant predictors of infant’s weight gain. Conclusion: Future research is needed to further delineate the primary driving forces behind immigrant Latina mothers’ feeding decisions and practices. Given the protective benefit of breastfeeding in reducing the risk of early childhood and adult obesity, present intervention efforts should focus primarily on the promotion of healthy feeding practices that encourage and support exclusive breastfeeding among this ethnic group.

The main aim of this thesis was to increase our understanding of the metabolic responses associated with short-term high-fat overfeeding. To this end, four separate studies are described in this thesis; each of which involved the provision of a high-fat, high-energy diet to young, healthy, lean individuals. The first of these experimental chapters (Chapter 2) determined the effects of a 7-day, high-fat (65%), high-energy (+50%) diet on postprandial metabolic and endocrine responses to a mixed meal challenge. This chapter demonstrates that 7-days of overfeeding impaired glycaemic control in our subject cohort but did not influence the response of selected gut hormones (acylated ghrelin, GLP-1 and GIP). In a mechanistic follow up study utilising stable isotope tracer methodology we then demonstrate that overfeeding-induced impairments in glycaemic control are attributable to subtle alterations in plasma glucose flux, rather than the overt tissue-specific adaptations (e.g. increased EGP, or reduced glucose disposal) that have previously been reported (Chapter 3). In an attempt to delineate the time-course of diet-induced impairments in glycaemic control, we then investigated the effects of 1-day of overfeeding (+80% energy with 73% of total energy coming as fat) (Chapter 4). Results demonstrate that a single day of overfeeding elicits responses which are comparable to 7-days of high-fat overfeeding; highlighting the rapidity with which excessive high-fat food intake can negatively influence glucose metabolism. In chapter 5 we utilised stable isotope tracer and muscle biopsy techniques to demonstrate that 7-days of high-fat overfeeding impairs glycaemic control but does not influence the fed-state mixed muscle protein fractional synthesis rate (FSR). In conclusion, the findings of this thesis demonstrate that while short-term high-fat overfeeding negatively influences whole-body glucose metabolism, skeletal muscle protein metabolism appears to be relatively unaffected in young, lean, healthy humans.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / O desequilíbrio nutricional no início da vida leva ao desenvolvimento da obesidade, diabetes e doenças cardiovasculares na idade adulta. Este estudo teve como objetivo analisar os efeitos a longo prazo da hiperalimentação na lactação por meio do modelo de redução da ninhada na hemodinâmica e bioenergética cardíaca. Vinte e quatro camundongos machos Swiss adultos foram divididos em dois grupos (controle e hiperalimentado) submetidos a duas condições (linha de base e isquemia/reperfusão) formando quatro grupos no total: grupo controle linha de base (GCLB), grupo controle isquemia/reperfusão (GCIR), grupo hiperalimentado linha de base (GHLB) e o grupo hiperalimentado isquemia/reperfusão (GHIR), todos com seis camundongos/grupo. As alterações cardíacas foram analisadas por meio da hemodinâmica cardíaca, da respiração mitocondrial e da biologia molecular. Os parâmetros hemodinâmicos analisados foram a velocidade de contração (Max dP/dt), a velocidade de relaxamento (Min dP/dt), o tempo de relaxamento cardíaco isovolumétrico (Tau) e os batimentos por minuto (BPM). A respiração mitocondrial foi avaliada por meio da razão do controle respiratório (RCR) na oxidação de carboidratos e ácidos gordos, e finalmente, a biologia molecular, através de proteínas-chave como a proteína quinase B (AKT), a proteína quinase ativada por adenosina monofosfato (AMPK), a carnitina palmitoil transferase 1 (CPT-1), a proteína desacopladora 2 (UCP2), o 4-hidroxinonenal (4-HNE) e a gliceraldeído-3-fosfato desidrogenase (GAPDH). Os camundongos do GH desenvolveram maior peso corporal (30,95%, P<0,001), gordura epididimal (68,64%, P<0,001), gordura retroperitoneal (109,38%, P<0,01) e glicemia de jejum (19,52%, P<0,05) comparados aos do GC. Os parâmetros Max dP/dt e BPM apresentaram diminuição no GHIR quando comparado ao GHLB (P<0,001 e P<0,05). O parâmetro Min dP/dt apresentou-se reduzido no GCIR e GHIR quando comparado aos grupos GCLB e GCLB (P<0,05; P<0,0001 respectivamente). Camundongos do GHIR apresentaram redução do Tau quando comparado aos grupos GCIR e GHLB (P<0,0001). Estes desequilíbrios na hemodinâmica cardíaca foram associados a função mitocondrial, uma vez que, o GHLB apresenta a RCR reduzida para oxidação de ácidos graxos e carboidratos (P<0,05 e P<0,01, respectivamente) e o GHIR apenas na oxidação dos ácidos graxos (P<0,01). Além disso, o GHIR apresentou diversas alterações nas proteínas-chave do metabolismo energético cardíaco, como diminuição do conteúdo de AKT (P<0,05) e aumento do conteúdo de CPT-1 (P<0,05), 4-HNE (P<0,05) e GAPDH (P<0,05) quando comparado ao CGIR. Finalmente, a expressão do mRNA para CPT1, GAPDH e UCP2 foi aumentada no GHIR quando comparado aos GCIR (P<0,05) e GHLB (P<0,05). A expressão de mRNA para UCP2 e CPT-1 foi reduzida no GCIR quando comparado ao GCLB (P<0,01 e P<0,05, respectivamente). O estudo apresenta resultados consistentes, demonstrando efeitos deletérios sobre o metabolismo cardíaco adulto resultante de alterações nutricionais durante a lactação. / Early life nutritional imbalance induces obesity, diabetes and cardiovascular diseases when animals become adults. This study aimed to study the long-term effects of postnatal overfeeding by litter size reduction on animal weight and heart energy homeostasis. Twenty-four adult male mice were divided into two groups (control and overfed) and studied under two conditions (baseline and ischemia/reperfusion) forming four groups in total: control group baseline (CGBL), control group ischemia/reperfusion (CGIR), obese group baseline (OGBL) and obese group ischemia/reperfusion (OGIR) all with 6 mice/group. Changes in heart were analyzed by cardiac hemodynamic, mitochondrial respiration and molecular biology. Hemodynamic parameters analyzed were speed of contraction (Max dP/dt), speed of relaxation (Min dP/dt), isovolumetric relaxation time (Tau) and beats per minute (BPM), mitochondrial respiration by respiratory control ratio (RCR) in carbohydrate and fatty acid oxidation and molecular biology by key proteins like protein kinase B (AKT), adenosine monophosphate-activated protein kinase (AMPK), carnitine palmitoil palmitoyltransferase 1 (CPT1), uncoupling protein 2 (UCP2), 4-hydroxynonenal (4-HNE) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The OG developed higher body weight (30.95%, P<0.001), epididymal fat (68.64%, P<0.001), retroperitoneal fat (109.38%, P<0.01) and fasting glucose (19.52%, P<0.05) compared to the CG. The parameters Max dP/dt and BPM were significantly decreased in OGIR compared to OGBL (P<0.001 and P<0.05). Min dP/dt was significantly decreased in CGIR and OGIR compared to CGBL (P<0.05) and OGBL (P<0,0001) respectively . Tau was significantly decreased in OGIR compared to CGIR and OGBL (P<0.0001). Theses impairments of cardiac hemodynamic were associated to mitochondrial uncoupling since OGBL presented decreased of RCR, in both carbohydrate and fatty acid oxidation (P<0.05 and P<0.01, respectively) and OGIR only in fatty acid oxidation (P<0.01). Moreover, OGIR showed higher alterations in key proteins of cardiac energetic metabolism with decreasing AKT content (P<0.05) and increasing CPT1 (p<0.05), 4-HNE (P<0.05) and GAPDH contents (P<0.05) when compared to CGIR. Finally, the expression of mRNA for CPT1, GAPDH and UCP2 was increased in OGIR compared to CGIR (P<0.05) and OGBL (P<0.05). The expression of mRNA for UCP2 and CPT1 was decreased in CGIR compared to CGBL (P<0.01 and P<0.05, respectively). Finally, the study presents consistent results demonstrating deleterious effects on adult heart metabolism resulting from nutritional changes during lactation.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / O desequilíbrio nutricional no início da vida leva ao desenvolvimento da obesidade, diabetes e doenças cardiovasculares na idade adulta. Este estudo teve como objetivo analisar os efeitos a longo prazo da hiperalimentação na lactação por meio do modelo de redução da ninhada na hemodinâmica e bioenergética cardíaca. Vinte e quatro camundongos machos Swiss adultos foram divididos em dois grupos (controle e hiperalimentado) submetidos a duas condições (linha de base e isquemia/reperfusão) formando quatro grupos no total: grupo controle linha de base (GCLB), grupo controle isquemia/reperfusão (GCIR), grupo hiperalimentado linha de base (GHLB) e o grupo hiperalimentado isquemia/reperfusão (GHIR), todos com seis camundongos/grupo. As alterações cardíacas foram analisadas por meio da hemodinâmica cardíaca, da respiração mitocondrial e da biologia molecular. Os parâmetros hemodinâmicos analisados foram a velocidade de contração (Max dP/dt), a velocidade de relaxamento (Min dP/dt), o tempo de relaxamento cardíaco isovolumétrico (Tau) e os batimentos por minuto (BPM). A respiração mitocondrial foi avaliada por meio da razão do controle respiratório (RCR) na oxidação de carboidratos e ácidos gordos, e finalmente, a biologia molecular, através de proteínas-chave como a proteína quinase B (AKT), a proteína quinase ativada por adenosina monofosfato (AMPK), a carnitina palmitoil transferase 1 (CPT-1), a proteína desacopladora 2 (UCP2), o 4-hidroxinonenal (4-HNE) e a gliceraldeído-3-fosfato desidrogenase (GAPDH). Os camundongos do GH desenvolveram maior peso corporal (30,95%, P<0,001), gordura epididimal (68,64%, P<0,001), gordura retroperitoneal (109,38%, P<0,01) e glicemia de jejum (19,52%, P<0,05) comparados aos do GC. Os parâmetros Max dP/dt e BPM apresentaram diminuição no GHIR quando comparado ao GHLB (P<0,001 e P<0,05). O parâmetro Min dP/dt apresentou-se reduzido no GCIR e GHIR quando comparado aos grupos GCLB e GCLB (P<0,05; P<0,0001 respectivamente). Camundongos do GHIR apresentaram redução do Tau quando comparado aos grupos GCIR e GHLB (P<0,0001). Estes desequilíbrios na hemodinâmica cardíaca foram associados a função mitocondrial, uma vez que, o GHLB apresenta a RCR reduzida para oxidação de ácidos graxos e carboidratos (P<0,05 e P<0,01, respectivamente) e o GHIR apenas na oxidação dos ácidos graxos (P<0,01). Além disso, o GHIR apresentou diversas alterações nas proteínas-chave do metabolismo energético cardíaco, como diminuição do conteúdo de AKT (P<0,05) e aumento do conteúdo de CPT-1 (P<0,05), 4-HNE (P<0,05) e GAPDH (P<0,05) quando comparado ao CGIR. Finalmente, a expressão do mRNA para CPT1, GAPDH e UCP2 foi aumentada no GHIR quando comparado aos GCIR (P<0,05) e GHLB (P<0,05). A expressão de mRNA para UCP2 e CPT-1 foi reduzida no GCIR quando comparado ao GCLB (P<0,01 e P<0,05, respectivamente). O estudo apresenta resultados consistentes, demonstrando efeitos deletérios sobre o metabolismo cardíaco adulto resultante de alterações nutricionais durante a lactação. / Early life nutritional imbalance induces obesity, diabetes and cardiovascular diseases when animals become adults. This study aimed to study the long-term effects of postnatal overfeeding by litter size reduction on animal weight and heart energy homeostasis. Twenty-four adult male mice were divided into two groups (control and overfed) and studied under two conditions (baseline and ischemia/reperfusion) forming four groups in total: control group baseline (CGBL), control group ischemia/reperfusion (CGIR), obese group baseline (OGBL) and obese group ischemia/reperfusion (OGIR) all with 6 mice/group. Changes in heart were analyzed by cardiac hemodynamic, mitochondrial respiration and molecular biology. Hemodynamic parameters analyzed were speed of contraction (Max dP/dt), speed of relaxation (Min dP/dt), isovolumetric relaxation time (Tau) and beats per minute (BPM), mitochondrial respiration by respiratory control ratio (RCR) in carbohydrate and fatty acid oxidation and molecular biology by key proteins like protein kinase B (AKT), adenosine monophosphate-activated protein kinase (AMPK), carnitine palmitoil palmitoyltransferase 1 (CPT1), uncoupling protein 2 (UCP2), 4-hydroxynonenal (4-HNE) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The OG developed higher body weight (30.95%, P<0.001), epididymal fat (68.64%, P<0.001), retroperitoneal fat (109.38%, P<0.01) and fasting glucose (19.52%, P<0.05) compared to the CG. The parameters Max dP/dt and BPM were significantly decreased in OGIR compared to OGBL (P<0.001 and P<0.05). Min dP/dt was significantly decreased in CGIR and OGIR compared to CGBL (P<0.05) and OGBL (P<0,0001) respectively . Tau was significantly decreased in OGIR compared to CGIR and OGBL (P<0.0001). Theses impairments of cardiac hemodynamic were associated to mitochondrial uncoupling since OGBL presented decreased of RCR, in both carbohydrate and fatty acid oxidation (P<0.05 and P<0.01, respectively) and OGIR only in fatty acid oxidation (P<0.01). Moreover, OGIR showed higher alterations in key proteins of cardiac energetic metabolism with decreasing AKT content (P<0.05) and increasing CPT1 (p<0.05), 4-HNE (P<0.05) and GAPDH contents (P<0.05) when compared to CGIR. Finally, the expression of mRNA for CPT1, GAPDH and UCP2 was increased in OGIR compared to CGIR (P<0.05) and OGBL (P<0.05). The expression of mRNA for UCP2 and CPT1 was decreased in CGIR compared to CGBL (P<0.01 and P<0.05, respectively). Finally, the study presents consistent results demonstrating deleterious effects on adult heart metabolism resulting from nutritional changes during lactation.