Search

Neutral energy and macronutrient balances are needed for the maintenance of a stable body weight. High-fat diets promote fat accumulation. This fact is not only due to the induction of a caloric hyperphagia, but also to the failure to adjust fat oxidation in response to an excess of fat intake. This situation does not occur with carbohydrates. In addition, the fatty acid composition of dietary fat can also be an important factor determining the resulting level of body weight and body energy stores. The modifications induced in adipocyte membrane fatty acid composition and in stored triglycerides lead to changes in the efficiency of the lipid mobilization. On the other hand, the activity of lipoprotein-lipase and lipogenic enzymes can be modulated by some fatty acids. The fate of the different fatty acids is not the same. Some of them are preferentially oxidized, others are stored and others play a structural role. Finally, diet-induced thermogenesis is increased by certain fatty acids and that contributes to an increased energy expenditure.

ABSTRACT Objective: To identify the prevalence of weight dissatisfaction among adolescents aged 10-19 years and stratify the analysis by sex. Data source: A literature review of cross-sectional studies among healthy adolescents was performed. The U.S. National Library of Medicine/National Institutes of Health (PubMed), Ovid® (Wolters Kluwer), The Cumulative Index to Nursing and Allied Health Literature (CINAHL), and American Psychological Association (PsycINFO®) databases were searched between May 2019 and January 2020. Data synthesis: Initially, 3,700 records were identified, and 10 papers were obtained through other sources. After the removal of duplicates, 1,732 records were screened based on the titles and abstracts, and 126 were preselected for full-text analysis. After the application of the eligibility criteria, 34 papers were included in the present review. The studies were published between 1997 and 2020. The sample size ranged from 103,000 adolescents. The prevalence of weight dissatisfaction ranged from 18.0 to 56.6% in both sexes (10.8-82.5% among boys and 19.2-83.8% among girls). Conclusions: Based on the findings of the present systematic review, the prevalence of weight dissatisfaction is high among adolescents, especially girls. Such information can contribute to the planning of health and education programs addressing the issue of weight in adolescents.

This paper targets the quality of tifton bermudagrass (Cynodon spp.) and alfalfa (Medicago sativa) hays in isoproteic and isoenergetic diets on horse body biometrics. Six equines, between 6.5±0.5 years old and with an mean body weight of 354±50kg, were used in this study. The treatments consisted of six diets and the experimental delineation was the Latin square (6x6). The diet’s forage was composed by a combination of hays, in a factorial scheme (2x3), with two forages (tifton bermudagrass and alfalfa) and three types of hay (A, B and C). There was a significant effect in the variables body weight, abdominal girth, fecal water content, and fecal production for the forage type. Greater digestibility coefficient of dietary dry matter values were identified in the diets composed by type A and B alfalfa hay (64.71±2.38% and 63.45±2.41%, respectively), that have significantly surpassed (P = 0.0061) the results obtained for the type C hay diets. It was possible to conclude that the alfalfa hay provided a reduction in the horse’s body weight and thoracic perimeter, what can be explained by the greater verified digestibility, as well as the lesser fecal water retention with the diets containing only the legume.

Long-term selection experiments provide a valuable resource for understanding the genetic changes that take place in animal improvement programs. The Virginia chicken lines have for more than 50 years been subjected to single-trait, bi-directional, divergent selection for high and low juvenile body weight. It is one of the most well studied experimental populations in agricultural animals and has played an instrumental role in the understanding of the genetic basis of complex traits. In this paper, we summarize the findings from the more recent publications focusing on the efforts to identify the loci contributing to selection response as well as discuss the currently ongoing research. We conclude by describing some future research prospects that promise to bring new, interesting insights into the biology of complex traits in the near future and their implications for future animal improvement programs.Experimentos de seleção a longo prazo constituem um recurso valioso para a compreensão das alterações genéticas em programas de melhoramento animal. As linhagens de frango de Virgínia há mais de 50 anos foram submetidas à seleção unicaracterística, bi-direcional e divergente para alto e baixo peso corporal em animais jovens. Trata-se de uma das populações experimentais em agropecuária que mais estudadas, desempenhando um papel fundamental na compreensão da base genética de características complexas. Neste artigo, resumimos os resultados das publicações mais recentes que focaram em identificar locos que contribuem para a resposta de seleção, bem como discutir as pesquisas atuais. Concluímos descrevendo algumas perspectivas de pesquisas que prometem trazer descobertas interessantes sobre a biologia dos multicaracteres em um futuro próximo e suas implicações para programas de melhoramento animal.

Los frutos secos han formado parte de la alimentación del hombre desde tiempo inmemorial, siendo muy apreciados e incorporándose a multitud de platos, preferentemente dulces y postres. Sin embargo el interés por este tipo de alimentos se ha incrementado de forma espectacular en las últimas décadas. Así numerosos estudios epidemiológicos han demostrado los efectos protectores del consumo de frutos secos disminuyendo el riesgo de padecer enfermedades cardiovasculares en distintos grupos de personas. Hasta el momento se han realizado ensayos clínicos con todos los tipos de frutos secos (almendras, nueces, pistachos, nueces de Macadamia, cacahuetes) que han producido un efecto positivo en el perfil lipoproteico, disminuyendo el colesterol total y las lipoproteínas de baja densidad (LDL) en plasma. No obstante, aún no ha sido demostrado si estos efectos se deben únicamente a su contenido y composición en ácidos grasos o a otros componentes minoritarios de los frutos secos como tocoferoles, fitosteroles y fitoestrógenos. Además las investigaciones que relacionan enfermedades cerebrovasculares y consumo de nueces son escasas. En este trabajo se revisan aspectos comparativos de la composición de los frutos secos, así como los posibles efectos de su consumo sobre peso corporal, metabolismo lipoproteico y protección frente a enfermedades cerebro y cardiovasculares. Teniendo en cuenta estos estudios, se recomienda la inclusión de 25 g/día de frutos secos, en el marco de una dieta prudente. Se proponen algunas líneas futuras de actuación en el estudio de los frutos secos.Nuts, cardio and cerebrovascular risks. A Spanish perspective. Nuts have been included in human diets for ages. They are very appreciated and used as a central component of sweets and desserts. However, during the last decades, scientific interest in those foods has increased enormously as many epidemiologic studies show protective effects of nut consumption on coronary heart disease in different population groups. To date, many clinical trials have analyzed the positive effects of nuts consumption (almond, walnut, pistachio, Macadamia nut, and pecan) on the lipid profile, decreasing total and low density lipoproteins (LDL) cholesterol. However, whether these effects are only due to their fatty acid composition or to any other bioactive compounds, such as tocopherols, phytosterols and phytoestrogens, it is still unknown. This paper, aims to reviewcomparative composition aspects of nuts, such as the positive effects on body weight, lipoprotein metabolism, and protection against cardiovascular and cerebrovascular diseases. The inclusion of 25 g/day of nuts, mainly raw, into a prudent diet seems to be recommended. Further investigations, as actual information is still scarce, in order to dilucidate the relationship between nuts consumption and vascular diseases are proposed.

Se describieron las pautas de distribución cutáneo-adiposa en una muestra de 580 adolescentes de la ciudad de Córdoba, Argentina, con la utilización como variables indicadoras de 3 espesores cutáneo-adiposos. Se verificó en varones la tendencia a la redistribución de la grasa corporal desde la extremidad superior hacia el tronco, mientras que en las mujeres el mayor acúmulo relativo de grasa de advirtió en el pliegue tricipital. Se observó además que tanto los varones como las mujeres tienden con la edad a acumular tejido graso en la parte superior del tronco. En una submuestra constituida por los individuos que presentaban el valor de la suma de los 3 pliegues por encima del percentilo 75 se obtuvo un resultado que difería de manera sensible del antes expuesto. En este subgrupo se evidenció que los dos sexos existía una mayor concentración de tejido adiposo en el tronco. Sin embargo, mientras en las mujeres el acúmulo de grasa se producía principalmente en la parte superior del tronco, en los varones esto ocurría en el abdomen. Los resultados de este trabajo indican de esta forma que la distribución relativa de la grasa subcutánea se encuentra muy influenciada por la cantidad absoluta del tejido adiposo corporalThe patterns of skin adipose distribution are described in a sample of 580 adolescents from Córdoba, Argentina, by using 3 skin adipose thicknesses as indicator variables. The trend to the redistribution of the body fat from the upper limbs to the trunk was confirmed among men, whereas in women the highest relative accumulation of fat was observed in the tricipital skinfold. As age increases men and women tend to accumulate adipose tissue in the upper part of the trunk. In a subsample that was composed of individuals that had the value of the addition of the 3 skinfolds over percentile 45 it was obtained a result that was significantly different from the above mentioned. In this subgroup it was proved that in both sexes there is a higher concentration of adipose tissue in the trunk. Fat is mainly accumulated in the upper part of the trunk among women and in the abdomen in men. The results of this paper show that the relative distribution of subcutaneous fat is higly influenced by the absolute amount of body adipose tissue

Las hormigas cortadoras de hojas de los géneros Atta Fabricius y Acromyrmex Mayr de la tribu Attini, son eficientes cosechadoras. Se ha observado que las obreras forrajeadoras de estas hormigas cosechan frecuentemente fragmentos de hojas que se corresponden con el peso de las hormigas. En este trabajo se evalúa la relación entre el peso de la carga transportada por individuos de Acromyrmex lobicornis Emery 1887, con el peso de la hormiga, a dos diferentes distancias desde el nido, en condiciones de laboratorio. Según los resultados, se determinó que el peso de la carga transportada está asociado con el peso de la hormiga, ya que las hormigas más grandes llevaron cargas más pesadas. A mayores distancias esta relación lineal se debilita. Se concluye que la optimización de entrada del recurso forrajero al nido es un proceso complejo en las especies del género Acromyrmex, lo que puede ser afectado no sólo por el peso corporal sino también por varios factores como las condiciones ambientales, composición química de la planta, y necesidades nutricionales de la coloniaLeaf-cutting ants belonging to the genera Atta Fabricius and Acromyrmex Mayr (Attini) are efficient harvesters. Workers frequently carry leaf fragments to the nest, which weight is related to the ant body weight. In this paper the effect of two foraging distances are evalued on the relationship between these two variables. Observations were made in an artificial nest of Acromyrmex lobicornis. Results indicated that at short distances leaf weight is linearlly related with the ant weight while at longer distances this relationship is weakened. Thus, we conclude that Acromyrmex optimum leaf harvest is a complex process that could be affected not only by the ant weight but also environmental conditions, plant chemical composition, and colony nutritional demands