Levels and degradability of crude protein in digestive metabolism and performance of dairy cows / Níveis e degradabilidade da proteína bruta no metabolismo digestivo e desempenho de vacas leiteiras

Two experiments were conducted to evaluate the effect of the level and degradability of crude protein (CP) on the digestive metabolism and productive performance of dairy cows. In both experiments, 15 Holstein cows with 585 ± 40 kg of body weight were distributed in a Latin square design with five contemporary squares, three periods of 21 days and three treatments. In experiment 1, treatments consisted of three CP levels (130, 160 or 180 g CP/kg DM), while in experiment 2, the treatments consisted of three levels of rumen degradable protein (RDP; 80, 100 or 120 g RDP/kg DM) in diets with average of 163 g CP/kg DM. Variables evaluated in both experiments were dry matter intake (DMI), total apparent digestibility, milk yield (MY) and composition, ruminal fermentation and N balance. In experiment 1, the increase of CP from 130 to 180 linearly increased the organic matter, CP, neutral detergent fiber (NDF) and acid detergent fiber (ADF) intake (kg) and the apparent total digestibility coefficient of DM and CP. In addition, a linear increase of MY, fat corrected milk (FCM) and daily production of fat, protein, lactose, casein and total solids was observed. A linear increase in ruminal ammoniacal nitrogen (NH3-N) concentration and nitrogen excretion in milk, feces and urine was also observed. However, there was no observed effect on SCFA concentration. In experiment 2, the increase of the RDP from 80 to 120 increased the DMI, MY, FCM, milk protein content and digestibility coefficient of the NDF, ADF and ethereal extract. Additionally, there was an increase in NH3-N concentration and milk nitrogen excretion. The studies indicated that the increase of CP content up to 100 g RDP/kg DM increased the DMI and the productive performance of the cows, but also increased urine N. Thus, it is desirable that the increase of the CP through the increase of the RDP is carried out up to 100 g of RDP/kg DM, since there is elimination of nitrogen, decrease of milk yield and decrease of propionic acid in values above that level.(AU)

Dois experimentos foram realizados com o objetivo de avaliar o efeito do nível e da degradabilidade da proteína bruta (PB) no metabolismo digestivo e no desempenho produtivo de vacas leiteiras. Nos dois experimentos, 15 vacas da raça Holandesa com 585 ± 40 kg de peso corporal foram distribuídas em delineamento do tipo quadrado latino com cinco quadrados contemporâneos, sendo três períodos de 21 dias e três tratamentos. No experimento 1, os tratamentos consistiram de três níveis de PB (130, 160 ou 180 g CP/kg de MS), enquanto que no experimento 2, os tratamentos consistiram de três níveis de proteína degradável no rúmen (PDR; 80, 100 ou 120 g de PDR/kg MS) em dietas com média de 163 g CP/kg MS. As variáveis avaliadas nos dois experimentos foram: consumo de matéria seca (CMS), digestibilidade aparente total, produção e composição do leite (PL), fermentação ruminal e balanço de N. No experimento 1, o aumento da PB de 130 para 180 aumentou linearmente o consumo de matéria orgânica, PB, fibra detergente neutro (FDN), fibra em detergente ácido (ADF) (kg) e o aparente coeficiente de digestibilidade total de MS e PB. Além disso, foi observado um aumento linear da PL, leite corrigido para gordura (LCG) e produção diária de gordura, proteína, lactose, caseína e sólidos totais. Também foi observado aumento linear na concentração de nitrogênio amoniacal ruminal (N-NH3) e excreção de nitrogênio no leite, fezes e urina. No entanto, não foi observado efeito na concentração de ácidos graxos de cadeia curta. No experimento 2, o aumento do PDR de 80 para 120 aumentou o CMS, PL, LCG, teor de proteína do leite e o coeficiente de digestibilidade do FDN, FDA e extrato etéreo. Além disso, houve aumento na concentração de N-NH3 e excreção de nitrogênio no leite. Os estudos indicaram que o aumento do teor de PB em até 100 g RDP/kg de MS aumentou o CMS e o desempenho produtivo das vacas, mas também aumentou o N urinário. Assim, é desejável que o aumento da PB através do aumento da PDR seja realizado até 100 g de PDR/kg de MS, uma vez que há eliminação de nitrogênio, diminuição da produção de leite e diminuição do ácido propiônico em valores acima desse nível.(AU)

Influencing factors on single-cell protein production by submerged fermentation: a review

Since more than twenty years ago, some species of bacteria and fungi have been used to produce protein biomass or single-cell protein (SCP), with inexpensive feedstock and wastes being used as their sources of carbon and energy. The role of SCP as a safe food and feed is being highlighted more because of the worldwide protein scarcity. Even though SCP has been successfully commercialized in the UK for decades, study of optimal fermentation conditions, various potential substrates, and a broad range of microorganisms is still being pursued by many researchers. In this article, commonly used methods for the production of SCP and different fermentation systems are briefly reviewed, with submerged fermentation being highlighted as a more commonly used method. Emphasis is given to the effect of influencing factors on the biomass yield and productivity in an effort to provide a comprehensive review for researchers in related fields of interest.

Protein intake and weight gain among low-income pregnant women from Mesquita County, Rio de Janeiro, Brazil / Consumo de proteína e ganho de peso entre gestantes de baixa renda do município de Mesquita, Rio de Janeiro, Brasil

ABSTRACT Objective To evaluate the effect of protein intake on body weight gain at pregnancy. Methods A cross-sectional study was carried out with 297 women who delivered a child at the maternity ward of Municipal Hospital Leonel de Moura Brizola in Mesquita city in the state of Rio de Janeiro. Sociodemographic and anthropometric data were collected through the use of a structured questionnaire at first week after delivery. Food intake was assessed by a food frequency questionnaire. Protein intake per kilogram of body weight (g/kg per day) during pregnancy was categorized as high or low protein intake according to overall median levels. Hierarchical multiple linear regression was fitted to estimate the effect of protein intake per kg during pregnancy on weight gain. Results Women presented an average weight gain of 12.8kg (SD=6.34) and 26.8kg/m2 (SD=4.78) of Body Mass Index. Those who consumed a diet with high levels of protein content significantly presented less weight at postpartum (p<0.01) lower Early-Pregnancy Body Mass Index (p<0.01). In the hierarchical linear regression, it was found a negative association of protein intake per kg and Weight gain (b=-4.3025; IC95%=-6.0215; -2.5836; p<0.01). In the final model, all others covariates (energy, schooling, family income and gestational age) were significantly associated with the outcome (p<0.05). The additional model showed a negatively association between Early-Pregnancy Body Mass Index and weight gain (b=-0.2951; IC95%= -0.4987; -0.0915; p<0.01). Conclusion Higher levels of protein intake per kg of body weight during pregnancy were associated with lower weight gain.

RESUMO Objetivo Este estudo teve como objetivo testar a associação entre a ingestão de proteína e o ganho de peso na gestação. Métodos Foi realizado um estudo transversal com 297 mulheres que deram à luz na maternidade do Hospital Municipal Leonel de Moura Brizola, na cidade de Mesquita, situada na baixada do estado do Rio de Janeiro. Os dados sociodemográficos e antropométricos foram coletados na primeira semana após o parto, com base em um questionário estruturado. Aplicou-se um questionário de frequência do consumo alimentar para avaliar a Ingestão de Proteína durante a gravidez, que foi classificada como alta ou baixa de acordo com os valores medianos observados. Adotou-se a regressão hierárquica linear múltipla para estimar o efeito da ingestão de proteína (ptn) por quilograma (kg) sobre o ganho de peso. Resultados As gestantes apresentaram, em média, um ganho de peso de 12,8kg (DP=6,34) e um Índice de Massa Corporal Pré-Gestacional de 26,8kg/m2 (DP=4,78). As gestantes com alta ingestão de proteína apresentaram valores significantemente menores em relação ao peso no pós-parto (p<0,01) e ao Índice de Massa Corporal pré-gestacional (p<0,001). No modelo final, todas as covariáveis (energia, escolaridade, renda familiar e idade gestacional) foram associadas ao desfecho (p<0,05), sendo verificada uma associação negativa entre a ingestão de ptn/kg e o ganho de peso (b=-4.3025; -6.0215; -2.5836 IC95%; p<0,01). No modelo adicional, observou--se uma associação negativa entre o Índice de Massa Corporal Pré-Gestacional e o ganho de peso (b=-4.3025; IC95%=-6.0215; -2.5836; p<0,01). Conclusão A pesquisa concluiu que teores elevados de proteína dietética foram associados com menores valores de ganho de peso na gestação.

A new approach to feed frequency studies and protein intake regulation in juvenile pirarucu

ABSTRACT This study aimed to investigate pirarucu's (Arapaima gigas) ability to trigger a self-feeding system to regulate protein intake between two standard diets that contained 39% and 49% of crude protein. The same system allowed the evaluation of daily feeding and locomotor activity rhythms. Eighteen fish (654.44±26.85g) were distributed into six 250 L tanks (3 fish/tank). Fish had free access to both diets (39% vs. 49% protein) by feeders (2 per tank), adapted to be activated by fish themselves. This system was connected to a computer system. After an adaptation period, fish learned to activate feeders and the mean food intake recorded was 2.14% of their body weight on a daily basis. Fish showed feeding (72.48%) and locomotor (72.49%) activity predominantly during the daytime, and daily variations of choice between diets, but fixed a protein intake feeding target at 44.53%. These results should be considered when discussing feeding behavior, feeding schedules and diet intake regulations.

Historical review of clinical vaccine studies at Oswaldo Cruz Institute and Oswaldo Cruz Foundation - technological development issues

This paper presents, from the perspective of technological development and production, the results of an investigation examining 61 clinical studies with vaccines conducted in Brazil between 1938-2013, with the participation of the Oswaldo Cruz Institute (IOC) and the Oswaldo Cruz Foundation (Fiocruz). These studies have been identified and reviewed according to criteria, such as the kind of vaccine (viral, bacterial, parasitic), their rationale, design and methodological strategies. The results indicate that IOC and Fiocruz have accumulated along this time significant knowledge and experience for the performance of studies in all clinical phases and are prepared for the development of new vaccines products and processes. We recommend national policy strategies to overcome existing regulatory and financing constraints.

Substituição do resíduo da produção de palmito da Palmeira Real Australiana (Archontophoenix alexandrae) na silagem de cana-de-açúcar em dietas de ovinos / Replacing of residue from production of palm Palm Royal Australian (Archontophoenix alexandrae) in silage of sugar cane in diets of sheep

Objetivou-se avaliar a composição química, consumo voluntário e digestibilidade aparente de dietas contendo resíduo oriundo da produção de palmito da palmeira Real Australiana (Archontophoenix alexandrae) em substituição à cana-de-açúcarem ovinos. Foram utilizados 12 ovinos com peso vivo médio de 23,3 ± 2,8 kg, mantidos em gaiolas metabólicas distribuídos em seis quadrados latinos 2x2 implementado em esquema fatorial 3 x 2 (três tipos de resíduo - folha, bainha e composta - e dois níveis de substituição do resíduo, 5% e 15%). Verificou-se maior consumo de matéria seca (MS), matéria orgânica (MO), carboidratos não fibrosos (CNF) na substituição pelo resíduo composta. Os valores médios de digestibilidade aparente da MS, MO, Proteína bruta (PB), fibra insolúvel em detergente neutro corrigido para cinzas e proteína(FDNcp) e nível dietético de NDT foram maiores para o resíduo folha. Constatou- se efeito de interação entre resíduo e o nível de substituição sobre as excreções urinárias de nitrogênio total (EUN), balanço nitrogenado aparente (BNA) e compostos nitrogenados microbianos (NMIC). Resíduos da produção de palmito oriundos da palmeira Real Australiana podem ser utilizados como alimentos volumosos na dieta de animais ruminantes, sendo destes, o resíduo folha e composta os que apresentaram melhores respostas nas características avaliadas.

The aim of this study was to evaluate the chemical composition, voluntary intake and apparent digestibility of the diets containing residue from palm heart of Australian Royal Palm (Archontophoenix alexandrae) to replace sugar cane on sheep. Twelve sheep were used with average live weight of 23,3 ± 2,8 Kg and they placed in metabolism cages and distributed in six latin square 2 x 2 in a factorial design 3 x 2 (three types of residue -sheet, bark and composed - and two levels of residue’s replacement, 5% and 15%). It was observed higher intake of dry matter (DM), organic matter (OM), nonfiber carbohydrates (NFC) by substitution of composed residue. The average values of apparent digestibility of DM, OM, crude protein (CP), neutral detergent fibre correct for ash and protein (NDFap) and total digestible nutrients (TDN) were higher for sheet residue. There was interaction between type of residue and level of residue’s replacement on the urinary excretion of total nitrogen (NUE), apparent nitrogen balance (BNA) and microbial nitrogen compost (NMIC). Residues from palm heart of Australian Royal Palm can be used as roughage in the ruminants’diet, and of these residues, the sheet and composed residue showed better response in the evaluated characteristics.

The Role of Diet in Non-alcoholic Fatty Liver Disease / 대한소화기학회지

Prevalence of non-alcoholic fatty liver disease (NAFLD) is about 20-25% in Korean adults population. Obesity is strongly associated with NAFLD and the prevention of obesity is a major public issue. Unfortunately, pharmacological treatment of obesity and NAFLD remains uncertain. Only weight loss by dietary changes been shown to lead to histological improvement in fatty liver. So the nutrition therapy is a cornerstone of treatment for NAFLD. Epidemiologic studies show that saturated fat, trans-fatty acid, carbohydrate, and simple sugar have strong correlation with intrahepatic fat accumulation. But, true associations with specific nutrients still remain unclear. Recently, fructose consumption has been rising in many countries and several epidemiologic studies show that fructose consumption has strong correlation with metabolic diseases. The consumption of excessively added sugar in the pathogenesis of steatohepatitis has received attention. Most clinicians agree with lifestyle modification are effective in histologic improvement. Total energy intake restriction is the most important action to reduce intrahepatic fat accumulation. Macronutrient composition may also have correlation with the development of NAFLD. To reduce the incidence of NAFLD, public statements on optimal dietary education program have been issused. Various specific dietary programs are suggested. Among them low fat diet and low carbohydrate diet are suggested in patients with NAFLD. However, there is no ideal diet to obtain the histological improvement in NAFLD. Further randomised controlled studies about specific diet are needed to determine the long-term benefit and histological improvement by ideal diet. Tailoring diet therapy to a patient's lifestyle is more important than universal specific dietary program.

Intracellular protein degradation: from a vague idea through the lysosome and the ubiquitin-proteasome system and onto human diseases and drug targeting / La degradación intracelular de proteínas: Desde una vaga idea, a través del lisosoma y el sistema ubiquitina-proteosoma a las enfermedades humanas y el blanco de las drogas

Between the 1950s and 1980s, scientists were focusing mostly on how the genetic code is transcribed to RNA and translated to proteins, but how proteins are degraded has remained a neglected research area. With the discovery of the lysosome by Christian de Duve it was assumed that cellular proteins are degraded within this organelle. Yet, several independent lines of experimental evidence strongly suggested that intracellular proteolysis is largely non-lysosomal, but the mechanisms involved remained obscure. The discovery of the ubiquitin-proteasome system resolved the enigma. We now recognize that degradation of intracellular proteins is involved in regulation of a broad array of cellular processes, such as cell cycle and division, regulation of transcription factors, and assurance of the cellular quality control. Not surprisingly, aberrations in the system have been implicated in the pathogenesis of human disease, such as malignancies and neurodegenerative disorders, which led subsequently to an increasing effort to develop mechanism-based drugs.

Entre los años 1950 y 1980 los científicos focalizaron sus estudios sobre la forma en que el código genético es transcripto al ARN y traducido a las proteínas, dejando de lado la forma en que éstas se degradan. Con el descubrimiento de los lisosomas por Christian de Duve se asumió que las proteínas se degradaban en el interior de esa organela. Sin embargo, varias líneas de trabajo independientes sugerían fuertemente que la proteólisis intracelular era en su mayor parte no lisosómica, aunque se desconocían sus mecanismos. El descubrimiento del sistema ubiquitina-proteosoma resolvió el enigma. Ahora sabemos que la degradación intracelular de proteínas participa en la regulación de un amplio espectro de procesos celulares como la división y el ciclo celular, la regulación de los factores de transcripción y el control de la calidad celular. No es sorpresa entonces que las aberraciones del sistema estén relacionadas con la patogénesis de enfermedades humanas como tumores y desórdenes neurodegenerativos, lo que llevó luego a un esfuerzo para desarrollar drogas basadas en este mecanismo.

Aquisição de açúcar e perfil de macronutrientes na cesta de alimentos adquirida pelas famílias brasileiras (2002-2003) / Sugar and overall macronutrient profile in the Brazilian family diet (2002-2003)

Avaliou-se a influência exercida pela aquisição de calorias de açúcar sobre a participação calórica dos demais macronutrientes da dieta. As estimativas deste estudo são baseadas em dados da Pesquisa de Orçamentos Familiares realizada no Brasil pelo Instituto Brasileiro de Geografia e Estatística entre julho de 2002 e junho de 2003. Modelos de regressão linear múltiplos foram utilizados para estudar a influência das calorias de açúcar sobre a participação calórica de cada um dos macronutrientes na aquisição domiciliar de alimentos com o controle do valor calórico total da aquisição de alimentos e variáveis sócio-demográficas. Cada caloria adquirida de açúcar eleva em 0,3 caloria a participação de gorduras na aquisição domiciliar de alimentos e diminui em 0,07 a participação de proteínas. Cada caloria de açúcar procedente de alimentos processados aumenta em 1,6 caloria a participação de gorduras e em 0,4 caloria de ácidos graxos saturados e diminui em 0,8 caloria a participação de outros carboidratos que não o açúcar. Os resultados encontrados trazem novas evidências sobre o papel prejudicial do açúcar à saúde humana.

This study evaluated the impact of calories from sugar on the calorie share of other macronutrients in the Brazilian family diet. The study's estimates are based on data from the Household Budget Survey conducted by the Brazilian Institute of Geography and Statistics from July 2002 to June 2003. Multiple linear regression models were used to study the impact of sugar calories on each of the macronutrients in household food acquisition, controlling for total energy content in food acquisition and socio-demographic variables. Each calorie from sugar purchases increases the share of calories from fat by 0.3 calories and decreases the share of calories from protein by 0.7 calories. Each calorie of sugar from processed foods increases the share from fat by 1.6 calories and the share from saturated fatty acids by 0.4 calories and decreases the share from non-sugar carbohydrates by 0.8 calories. The findings shed further light on the harmful role of sugar for human health.

Las dietas hiperproteicas y sus consecuencias metabólicas / Hiperproteicas diets and metabolic consequences

El consumo excesivo de proteínas produce un incremento en la excreción neta de ácidos, lo cual a su vez aumenta la excreción urinaria de calcio. Los efectos de la dieta sobre la excreción urinaria de ácidos y de calcio no sólo dependen de la cantidad de proteínas, sino que también pueden ser modificados por otros constituyentes de la alimentación, tales como el potasio y los equivalentes alcalinos de bicarbonato contenidos en las frutas y hortalizas. La deficiencia de estas bases de potasio en la dieta aumenta la carga ácida sistémica producida por las proteínas. En consecuencia, el resultado de una ingesta elevada en proteínas o bien deficiente en frutas y hortalizas es la generación de acidosis metabólica crónica, la cual, aún siendo de bajo grado, tiene efectos deletéreos sobre el organismo, incluyendo retardo del crecimiento en niños, disminución de la masa ósea y muscular en adultos, y formación de cálculos renales. En la presente revisión se resumen las evidencias actuales en relación a los efectos de las dietas hiperproteicas sobre distintos órganos y sistemas incluyendo el metabolismo hidroelectrolítico y ácido base, el metabolismo óseo, la función renal y la función endocrina. Asimismo se mencionan los aspectos particulares que influyen de un modo especial en los gupos de las edades extremas de la vida, los niños y los ancianos.

High protein intake produces an increase in net acid excretion, which in turn leads to an increase in urinary calcium. Effects of diet in urinary acid and calcium excretion depend not only on the protein content, but also may be modified by other constituents such as potassium and alkali equivalents of bicarbonate present in fruits and vegetables. Diets deficient in these potassium bases increase the acid load imposed by proteins. In consequence, diets with a high protein intake or poor in fruits and vegetables produce a low-grade systemic metabolic acidosis which exerts deleterious effects on the body, including growth retardation in children, decreased muscle and bone mass in adults, and kidney stone formation. This review intends to summarize the present evidence in relation to the effects of high protein diets in different organs and systems including hydroelectrolytic and acid base metabolism, bone metabolism, renal and endocrine function. Particular aspects that may exert a special influence in life extremes as childhood and old age are also addressed.

Efeito da oferta dietética de proteína sobre o ganho muscular, balanço nitrogenado e cinética da 15N-glicina de atletas em treinamento de musculação / Effect of the dietary protein intake on the muscular gain, nitrogen balance and 15N-glycine kinetics of athletes in resistance training

O efeito da oferta crescente de proteína sobre o ganho muscular, balanço nitrogenado e cinética da 15N-glicina de atletas de musculação foi estudado em seis jovens saudáveis, praticantes de treinamento com pesos (> 2 anos), sem uso de anabolizantes e concordes com os princípios éticos da pesquisa. Todos receberam adequações dietéticas (0,88g de proteína/kg/dia) pré-experimento de 2 semanas (D1) após o que se ofereceu, por idêntico período, dieta contendo 1,5g de proteína/kg de peso corporal/dia com 30kcal/g de proteína (dieta D2). A seguir receberam, nas próximas 2 semanas, a dieta D3, contendo 2,5g de proteína/kg de peso corporal/dia e 30 kcal/g proteína. As avaliações antropométricas, alimentares, biquímicas, balanço nitrogenado (BN) e cinética com 15N-glicina foram realizadas no início do estudo, pós D1 (M0) e no último dia das dietas D2 (M1) e D3 (M2). Ao final do estudo (4 semanas) houve aumento significativo na massa muscular (1,63±0,9kg), sem diferença entre D2 e D3. O BN acompanhou o consumo protéico/energético (M0 = -7,8g/dia; M1 = 5,6g/dia e M2 = 16,6g/dia) e a síntese protéica acompanhou o BN, com significância estatística (p<0,05) em relação ao basal (M0) mas semelhante entre D2 e D3 (M1 = 49,8±12,2g N/dia e M2 = 52,5±14,0g N/dia) e sem alteração significativa do catabolismo. Assim, os dados de BN e cinética da 15N-glicina indicam que a ingestão protéica recomendável para esses atletas é superior ao preconizado para sedentários (0,88g/kg) e inferior a 2,5g/kg de peso, sendo no caso, 1,5g de proteína/kg de peso/dia com ajuste do consumo energético para 30 kcal/g de proteína.

The effect of increased protein intake on the muscle mass gain, nitrogen balance and 15N-glycine kinetics was studied in six young, healthy subjects practitioners of strength training (> 2 years), without use of anabolic steroids and in agreement with the ethical principles of the research. All athletes received adequate diet (0.88g protein/kg/day) during 2 weeks prior the study (D1), and thereafter with diet providing 1.5g of protein/kg/day and 30kcal/g of protein (D2 diet) for the subsequent 2 weeks. Later on, they all received diet with 2.5g of protein/kg/day (D3 diet) and 30 kcal/g protein for the last two weeks. Body composition, food intake, blood biochemistry, nitrogen balance (NB) and 15N-glycine kinetics were determined at the beginning, after D1 (M0) and in the last days of the D2 (M1) and D3 (M2). The results showed at the end of the study (4 weeks) significant increase in muscle mass (1.63±0.9kg), without difference between D2 and D3. The NB followed the protein/energy consumption (M0 = -7.8g/day; M1 = 5.6g/day and D3 = 16.6g/day), the protein synthesis followed the NB, with M0 < (M1=M2) (M1 = 49.8±12.2g N/day and M2 = 52.5±14.0g N/day). Protein catabolism rate was similarly kept among diets. Thus, the results of the NB and 15N-glycine kinetics indicate that the recommended protein intake for these athletes is higher than the one for sedentary adults (0.88g/kg) and lower than 2.5g/kg, around 1.5g of protein/kg/day, with adjustment of the energy consumption to 30 kcal/g of protein.

O perfil de macronutrientes influencia a termogênese induzida pela dieta e a ingestão calórica / Macronutrient profile affects diet-induced thermogenesis and energy intake

The diet composition can interfere directly in the energy homeostase. In the energy metabolism, the oxidation pathway and diet-induced thermogenesis are differentiated by diet macronutrients proportion. In this respect, the high-proteindiet is the most thermogenic, compared to high-carbohydrate and high-lipid diets, while high-carbohydrate diet appears to increase the thermogenic effect more than high-lipid diet, but the studies arecontroversies. Towards energy intake, it can stimulate or inhibit the energy intake, according to the foods palatability, satiation and satiety degree, related to diet carbohydrate, protein and lipid content. A hierarchy has been observed for the satiating efficacies of the macronutrients protein, carbohydrate and fat, with protein as most satiating and fat as least satiating. In general, there are discrepancies between studies about the regulatory role of macronutrients in the components of energy expenditure and intake, due the methodological differences in the subjects, exposition time for diet, energy density, and total energy content. The present work seeks to analyze the more consistent scientific evidences toward the modulator role of diet composition on the diet induced thermogenesis and energy intake, for better understanding of obesity prevention and control by dietetic intervention.

A composição da dieta pode interferir diretamente na homeostase energética. No metabolismo energético, a via de oxidação e a termogênese induzida pela dieta são diferenciadas pela proporção de macronutrientes da dieta. Neste sentido, a dieta hiperprotéica émais termogênica que as dietas hiperglicídicas e hiperlipídicas, enquanto que as dietas ricas em carboidrato parecem ser mais termogênicas que as ricas em lipídio, mas os resultados ainda são controversos. Em relação à ingestão calórica, a composição da dieta pode estimular ou inibir a mesma, de acordo com a palatabilidade dos alimentos e o grau de saciação e saciedade, relacionadas às quantidades de carboidrato, proteína e lipídio da mesma. Uma hierarquia tem sido relatada para a capacidade dos macronutrientes em induzir saciedade em que a proteína é o mais sacietógeno ao contrário dos lipidios, que são os menos sacietógenos. De modo geral, ainda há discrepâncias entre os estudos, em relação ao papel regulador dos macronutrientes em componentes do gasto energético e na ingestão calórica, devido às diferenças metodológicas como amostra, tempo de exposição à dieta, densidade calórica e conteúdo calórico total da mesma. Desta forma, o presente trabalho tem como objetivo analisar as evidências científicas mais consistentes a respeito do papel modulador da composição da dieta na termogênese induzida pela dieta e na ingestão calórica, para melhor entendimento da prevenção e controle da obesidade pela intervenção dietética.

Efecto del sexo de la rata (Sprague Dawley) sobre la digestibilidad y razón neta de proteína en alimentos de distinta calidad proteica / Effect of rat (Sprague Dawley) sex on digestibility and net protein ratio in foods of different protein quality

The effect of grouping by sex Sprague Dawley rats on protein quality evaluation of three foods was studied. Bioassays performed were dry matter digestibility (DMD), apparent and true nitrogen digestibility (AND y TND) and net protein ratio (NPR). Foods of different protein quality used were dry whole milk, texturized soybean and high fiber breakfast cereal obtained from the local market. Casein was used as control. An experimental block design where the blocks were the groups of rats classified as mixed, female and male was used. Data of consumed diet, total feces and weight gain of each rat was recorded every third day. It was concluded that with the exception of the high fiber breakfast cereal, which showed significant differences between males and females in the true nitrogen digestibility parameter, in general grouping by sex did not have a significant effect on dry matter, AND, TND and NPR responses. These results suggest the possibility of using rats from either sex in these protein quality evaluation tests.

La influencia del agrupamiento por sexo de las ratas Sprague Dawley fue evaluada al determinar la calidad proteica en tres alimentos. Los bioensayos realizados fueron digestibilidad de materia seca (DMsec), digestibilidad de nitrógeno aparente y verdadera (DNap y DNver) y razón neta de proteína (NPR). Las muestras empleadas fueron alimentos de distinta calidad proteica: leche en polvo, soya texturizada y cereal, obtenidas del comercio local y caseína como control. Se utilizó un diseño experimental por grupos: mixto, hembras y machos. Se colectaron datos cada tercer día: alimento consumido, el total de heces y el incremento en peso de cada individuo. Se concluye de manera general, que el agrupamiento por sexo de la rata no tiene efecto significativo sobre la respuesta de estos bioensayos evaluados en los alimentos probados, a excepción del cereal que presentó diferencias significativas entre machos y hembras en el parámetro de DNver, sugiriendo que es factible utilizar ratas de diferente sexo en estas evaluaciones de calidad proteica.

effect of dexamethasone and high protein diet on protein metabolism in patients with head trauma

Injuries and head trauma are considered to produce stress in patients which is accompanied with increased body catabolism reflected as higher secretion of urinary urea nitrogen.To determine the effect of dexamethasone and high protein diet on protein metabolism in head trauma patients. Through a clinical trial, 24 head trauma patients were randomly divided into two groups in which one group received dexamethasone three times a day plus high protein diet [study group], and the second group was only high protein diet [control group] for 14 days. Determination of urea nitrogen was carried out on 24-hour urine specimens collect before and after 14 days following the administration of high protein diet. The excretion of urinary urea nitrogen was increased in case group whereas it was decreased [p<0.05] in control group. However, following the administration of high protein diet, the urea nitrogen content was reduced in both case and control groups and the reduction of this substance in control group was statically significant. Dexamethasone had no effect on improving the head trauma patients' conditions. Protein-rich diet caused a decrease in excretion of urinary urea nitrogen

The role of serum and urinary urea in the evaluation of enteral protein intake in adequate and small-for-gestational-age very low birth weight infants

INTRODUÇÃO E OBJETIVOS: Os recém-nascidos de muito baixo-peso (RNMBP) têm necessidades nutricionais especiais. Existe uma tendência atual de se individualizar a oferta protéica para essas crianças. O objetivo do trabalho é determinar a utilidade da uréia sérica e urinária como indicadores da oferta protéica em RNMBP adequados (AIG) e pequenos para a idade gestacional (PIG). TIPO DE ESTUDO E LOCAL: Estudo prospectivo realizado no Berçário Anexo à Maternidade Instituto da Criança "Prof. Pedro de Alcântara" do Hospital das Clínicas, Departamento de Pediatria da Faculdade de Medicina, Universidade de São Paulo, Brasil. MÉTODOS: Setenta e dois RNMBP (oferta protéica média = 3,7 g/kg/dia) foram incluídos, em um estudo de coorte prospectivo, em dois grupos: AIG (n = 34) e PIG (n = 38). Amostras de sangue, coletas de urina de seis horas (Ur6h) e em amostras isoladas (AIUr) foram obtidas para determinação de uréia e creatinina após a 3ª semana de vida e duas semanas após. Análise estatística: teste t de Student, correlação de Pearson e regressão linear (p < 0,05). RESULTADOS: Não houve diferença entre os grupos quanto aos níveis de uréia sérica, uréia Ur6h e uréia AIUr, bem como entre as duas avaliações dentro de cada grupo. A uréia sérica correlacionou-se à uréia Ur6h nos RNAIG e nos PIG, bem como à uréia AIUr nos RNPIG. A uréia Ur6h correlacionou-se à uréia AIUr nos RNAIG e nos RNPIG. Não houve correlação entre a oferta protéica e a uréia sérica ou urinária. CONCLUSÕES: A uréia sérica e a urinária não refletiram a oferta protéica quando foram utilizadas ofertas médias de 3,7 g/kg/dia. Uréia AIUr pode ser tão confiável quanto uréia da urina coletada por períodos mais longos.

Relação entre proteína dietética e calciúria em crianças e adolescentes com nefrolitíase / Relation between diet protein and calciuria in children and adolescents with nephrolitiasis

PURPOSE: The objective was to evaluate the quality of diet and the relationship between protein diet and calciuria in children and adolescents with nephrolithiasis. METHODS: Forty-nine children and adolescents (28 male and 21 female; 10.1 +/- 3.16 years old) with nephrolithiasis were included in study. Diet evaluation was performed over a 3 day period in order to determine nutrient consumption. The analysis of diets were carried out by DietWin Clínico 3.0 software. One 24-hour urine sample was collected for the measurement of calcium. Nutritional status was also assessed by Body Mass Index (BMI). RESULTS: The diet of patients containe insufficient energy and calcium. High levels of protein (69.64 +/- 16.42 gm), mainly animal source (65.81 +/- 11.45%) and low levels of calcium (500.95 +/- 284.64 mg) was observed (95%). Analysis of 24 hour urine samples revealed that 25.0% of the patients presented hypercalciuria. A positive correlation (r = 0.26680) between animal protein intake and calciuria was found, in opposite of vegetable protein and calciuria correlation (r = -0.2675). CONCLUSIONS: Animal protein of the diet has a significant effect in urinary excretion of calcium in patients with nephrolithiasis.

Controlling proteolytic degradation of the methionine enriched MB-1Trp protein

Protein design is currently used for the creation of new proteins with desirable traits, which include a superior nutritional value. One of the challenges of protein design in this area is to achieve the production of stable native-like proteins that resist the proteolytic pressure of the organism used for its production (the bioreactor). We report here the identification of a specific peptide bond sensitive to E. coli proteolysis in the designer protein MB-1Trp. In an attempt to reduce proteolysis, we have created a MB-1TrpHis gene library in which the two amino acids surrounding the peptide bond, N44 and L45, were randomized using degenerated oligonucleotides. The initial characterization of MB-1TrpHis N44E/L45V and MB-1TrpHis N44E/L45M, 2 variants of the library that were more resistant than the parent protein, was performed in order to investigate the nature of the mutants' resistance. Our results suggest that the mutants behaved like MB-1Trp regarding folding and thermal stability, and that proteolytic resistance is due to the elimination of the protease recognition site.

Probiotics enhance the recovery of gut atrophy in experimental malnutrition

AIM: The aim of this study was to evaluate the effect of probiotics on the recovery of the bowel atrophy induced by malnutrition in rats. METHODS: Twenty-and-six Wistar rats (200-250 g) were fed with either a normoproteic (sham group, n=6) or a free-protein diet (n=20)during 12 days. Twelve malnourished rats were randomized to recover during 15 days with either a hydrolyzed diet (control group, n=6) or the same diet enriched with probiotics (Streptococcus thermophilus and Lactobacilus helveticus; probiotic group, n=6). RESULTS: probiotic group showed similar gain of body, liver and bowel weight than controls. At the jejunum, both thevillus height (383±49 vs. 321±46mm; p=0,04) and crypt depth (157±31 vs. 125±10mm; p=0,04) were greater in probiotic group than in controls. The crypt depth at the cecum (214±22 vs. 169±43mm; p=0,05) and the wall width at both the cecum (410±18 vs. 340±61mm; p=0,02) and sigmoid (479±130 vs. 330±62mm; p=0,03) were higher in probiotic than in control group. CONCLUSION: Streptococcus thermophillus and Lactobacillus helveticus enhance the recovery of gut atrophy induced by malnutrition. Probiotics can be useful as oral adjuvants during the recovery of malnutrition.

Influência do componente protéico na consolidação de fraturas: trabalho experimental em ratos / Influence of the protein component upon fracture healing: an experimental study in rats

Os autores estudaram a influência da nutrição protéica na concolidação de fraturas em 40 ratos Lewis divididos em 4 grupos de 10. Durante 6 semanas os grupos 1,2 e 3 receberam respectivamente dietas com 0,19 por cento e 36 por cento de proteínas. O grupo 4 recebeu dieta sem proteínas durante as 2 primeiras semanas e com 36 por cento de proteínas nas 4 semanas seguintes. Foram realizadas fraturas nas tíbias esquerdas ao final de 2 semanas e após 4 semanas das fraturas os animais foram sacrificados para estudo dos calos ósseos. Para a avaliação dos resultados foram utilizadas medidas clínicas, bioquímicas, radiográficas, densitométricas, e histomorfométricas. Concluiu-se que a dieta hiperprotéica alterou a consolidação óssea produzindo um calo maior e mais resistente, mas não alterou a qualidade em concentração de cálcio e em porcentagem a quantidade de tecido ósseo.