Socio-economic variables influence the prevalence of inadequate nutrient intake in Brazilian adolescents: results from a population-based survey

Objective: To estimate the prevalence of inadequate nutrient intake among adolescents and the association between socio-economic variables and nutritional status. Design: Cross-sectional study with a population-based sample. Settings: The usual nutrient intake distribution was estimated using the Iowa State University method. The Estimated Average Requirement cut-off point method was used to determine the proportion of adolescents with inadequate intake for each nutrient, according to sex, income, parental educational level and nutritional status. Subjects: Twenty-four-hour dietary recalls were applied in 525 male and female Brazilian adolescents aged 14-18 years. Results: The highest prevalence of inadequate nutrient intake was observed for vitamin E (99% in both sexes). For male and female adolescents, the prevalence of inadequate intake was: Mg, 89% and 84%; vitamin A, 78% and 71 %; vitamin C, 79% and 53%; and vitamin B(6), 21% and 33%, respectively. The prevalence of inadequate intake for niacin, thiamin, riboflavin, Se, Cu and vitamin B(12) was <15 %. Individuals in the lower income and lower parental educational level strata had the highest risk of having inadequate intake for P, riboflavin and vitamins A, B(6) and B(12). Compared with non-overweight individuals, overweight individuals had a higher risk of inadequate intake for Mg, vitamin A, P, thiamin and riboflavin. Conclusions: The present study found a high prevalence of inadequate intake of nutrients that are recognised as being protective against chronic diseases. Adolescents in the lower income and lower parental educational level strata were less likely to have their nutrient intake requirements met.

Effect of fires on soil nutrient availability in an open savanna in Central Brazil

Fire is common in savannas but its effects on soil are poorly understood. We analyzed long-term effects of fire on surface soil of an open Brazilian savanna (campo sujo) in plots submitted to different fire regimes during 18 years. The five fire regimes were: unburned, quadrennial fires in middle dry season, and biennial fires in early, middle or late dry season. Soil was collected during the wet and the middle dry season of 2008, and analyzed for pH, organic matter, total N, potential acidity, exchangeable cations and available P, S, Mn, Cu, Zn and Fe. We applied multivariate analysis to search for patterns related to fire regimes, and to local climate, fuel, and fire behavior. Spearman test was used to establish correlations between soil variables and the multivariate analysis gradient structure. Seasonal differences were tested using t-test. We found evidence of long-term fire effects: the unburned plot was segregated mainly by lower soil pH; the quadrennial plot was also segregated by lower soil pH and higher amount of exchangeable cations; the time of burning during the dry season in biennial plots did not significantly affect soil availability of nutrients. Differences in elements amounts due to the season of soil sampling (wet or dry) were higher than due to the effect of fires. Higher availability of nutrients in the soil during the wet season was probably related to higher nutrient inputs via rainfall and higher microbial activity.

Nutrient Selection in the Absence of Taste Receptor Signaling

When allowed to choose between different macronutrients, most animals display a strong attraction toward carbohydrates compared with proteins. It remains uncertain, however, whether this food selection pattern depends primarily on the sensory properties intrinsic to each nutrient or, alternatively, metabolic signals can act independently of the hedonic value of sweetness to stimulate elevated sugar intake. Here we show that Trpm5(-/-) mice, which lack the cellular mechanisms required for sweet and several forms of L-amino acid taste transduction, develop a robust preference for D-glucose compared with isocaloric L-serine independently of the perception of sweetness. Moreover, a close relationship was found between glucose oxidation and taste-independent nutrient intake levels, with animals increasing intake as a function of glucose oxidation rates. Furthermore, microdialysis measurements revealed nutrient-specific dopaminergic responses in accumbens and dorsal striatum during intragastric infusions of glucose or serine. Specifically, intragastric infusions of glucose induced significantly higher levels of dopamine release compared with isocaloric serine in both ventral and dorsal striatum. Intragastric stimulation of dopamine release seemed to depend on glucose utilization, because administration of an anti-metabolic glucose analog resulted in lower dopamine levels in striatum, an effect that was reversed by intravenous glucose infusions. Together, our findings suggest that carbohydrate-specific preferences can develop independently of taste quality or caloric load, an effect associated with the ability of a given nutrient to regulate glucose metabolism and stimulate brain dopamine centers.

Chromium ions phytoaccumulation by three floating aquatic macrophytes from a nutrient medium

In the present work, the trivalent and hexavalent chromium phytoaccumulation by three living free floating aquatic macrophytes Salvinia auriculata, Pistia stratiotes, and Eicchornia crassipes was investigated in greenhouse. These plants were grown in hydroponic solutions supplied with non-toxic Cr3+ and Cr6+ chromium concentrations, performing six collections of nutrient media and plants in time from a batch system. The total chromium concentrations into Cr-doped hydroponic media and dry roots and aerial parts were assayed, by using the Synchrotron radiation X-ray fluorescence technique. The aquatic plant-based chromium removal data were described by using a nonstructural kinetic model, obtaining different bioaccumulation rate, ranging from 0.015 to 0.837 1 mg(-1) d(-1). The Cr3+ removal efficiency was about 90%, 50%, and 90% for the E. crassipes, P. stratiotes, and S. auriculata, respectively; while it was rather different for Cr6+ one, with values about 50%, 70%, and 90% for the E. crassipes, P. stratiotes, and S. auriculata.

Limnology of Macrobrachium amazonicum grow-out ponds subject to high inflow of nutrient-rich water and different stocking and harvest management

We evaluated the water characteristics and particle sedimentation in Macrobrachium amazonicum (Heller 1862) grow-out ponds supplied with a high inflow of nutrient-rich water. Prawns were subject to different stocking and harvesting strategies: upper-graded juveniles, lower-graded juveniles, non-graded juveniles + selective harvesting and traditional farming (non-grading juveniles and total harvest only). Dissolved oxygen, afternoon N-ammonia and N-nitrate and soluble orthophosphate were lower in the ponds in comparison with inflow water through the rearing cycle. Ponds stocked with the upper population fraction of graded prawns showed higher turbidity, total suspended solids and total Kjeldahl nitrogen than the remaining treatments. An increase in the chemical oxygen demand:biochemical oxygen demand ratio from inlet (4.9) to pond (7.1-8.0) waters indicated a non-readily biodegradable fraction enhancement in ponds. The sedimentation mean rate ranged from 0.08 to 0.16 mm day(-1) and sediment contained >80% of organic matter. The major factors affecting pond ecosystem dynamic were the organic load (due to primary production and feed addition) and bioturbation caused by stocking larger animals. Data suggest that M. amazonicum grow-out in ponds subjected to a high inflow of nutrient-rich water produce changes in the water properties, huge accumulation of organic sediment at the pond bottom and non-readily biodegradable material in the water column. However, the water quality remains suitable for aquaculture purposes. Therefore, nutrient-rich waters, when available, may represent a source of unpaid nutrients, which may be incorporated into economically valued biomass if managed properly.

Growth and body nutrient deposition of two broiler commercial genetic lines

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Nutrient digestibility, but not mineral absorption, is age-dependent in cats

Availability of nutrients is influenced by extremes of age, and a better characterization of this influence is necessary for appropriate development of foods and nutritional management throughout life stages of cats. This study investigated nutrient digestibility, mineral absorption, faeces and urine production in three groups of six young, mature and old cats fed two diets containing different energy densities. Apparent digestibility and mineral absorption were calculated by total collection method and values were tested with ANOVA and regression analysis. A quadratic relationship was detected between age and digestibility of dry matter, organic matter, crude protein, acid-hydrolysed fat and starch in the low-energy diet. Starch digestibility showed the same response in the high-energy diet. Young adult cats had intermediate digestibility, mature cats the highest and old cats the lowest. Mineral absorption (calcium, phosphorus, magnesium, sodium, potassium and chloride) and urinary pH were not different among groups. These findings confirm previous studies that found low digestibility of nutrients in some old cats, and support evidence that this trend is even more important in less digestible dry foods. on the contrary, data suggest that mineral formulations do not need to be varied in diets for adult cats of different ages.

Nutrient contents and production of rocket as affected by nitrogen concentrations in the nutritive solution

O empirismo no uso das soluções nutritivas é freqüente. Muitas vezes a mesma solução nutritiva é usada para diferentes espécies baseando-se apenas em semelhanças morfológicas. No entanto esta situação pode proporcionar desequilíbrio nutricional prejudicando tanto a produção quanto a qualidade do produto face o acúmulo de nitrato. Foi conduzido um trabalho em sistema hidropônico - NFT, com o objetivo de avaliar o efeito da concentração de nitrogênio na solução nutritiva na produção, nos teores de nutrientes e de nitrato em folhas de rúcula (Eruca sativa). O trabalho foi conduzido na primavera de 2003. Foram avaliadas quatro concentrações de nitrogênio na solução nutritiva (60,8; 121,6; 182,5; 243,5 mg L-1) e três cultivares de rúcula (Cultivada, Folha Larga e Selvática), sob delineamento de blocos ao acaso, fatorial 4 x 3, com quatro repetições. A cv. Cultivada apresentou maior estatura e fitomassa fresca de folhas, não diferindo da 'Folha Larga' quanto a número de folhas, teor de nitrato nas folhas e fitomassa seca e fresca da raiz. Houve incremento de NO3-, N, Ca e P e diminuição de Mg, K e S com o aumento da concentração de N na solução nutritiva. O cultivo da cv. Cultivada na concentração de 93 mg L-1 é a mais recomendada em função da maior produtividade e baixo teor de nitrato.

Soil, water and nutrient losses by interrill erosion from green cane cultivation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Compositional nutrient diagnosis of corn using the Mahalanobis distance as nutrient imbalance index

Parent, L. E., Natale, W. and Ziadi, N. 2009. Compositional nutrient diagnosis of corn using the Mahalanobis distance as nutrient imbalance index. Can. J. Soil Sci. 89: 383-390. Compositional nutrient diagnosis (CND) provides a plant nutrient imbalance index (CND - r(2)) with assumed chi(2) distribution. The Mahalanobis distance D(2), which detects outliers in compositional data sets, also has a chi(2) distribution. The objective of this paper was to compare D(2) and CND - r(2) nutrient imbalance indexes in corn (Zea mays L.). We measured grain yield as well as N, P, K, Ca, Mg, Cu, Fe, Mn, and Zn concentrations in the ear leaf at silk stage for 210 calibration sites in the St. Lawrence Lowlands [2300-2700 corn thermal units (CTU)] as well as 30 phosphorus (2300-2700 CTU; 10 sites) and 10 nitrogen (1900-2100 CTU; one site) replicated fertilizer treatments for validation. We derived CND norms as mean, standard deviation, and the inverse covariance matrix of centred log ratios (clr) for high yielding specimens (>= 9.0 Mg grain ha(-1) at 150 g H(2)O kg(-1) moisture content) in the 2300-2700 CTU zone. Using chi(2) = 17 (P < 0.05) with nine degrees of freedom (i.e., nine nutrients) as a rejection criterion for outliers and a yield threshold of 8.6 Mg ha(-1) after Cate-Nelson partitioning between low- and high-yielders in the P validation data set, D(2) misclassified two specimens compared with nine for CND -r(2). The D(2) classification was not significantly different from a chi(2) classification (P > 0.05), but the CND - r(2) classification differed significantly from chi(2) or D(2) (P < 0.001). A threshold value for nutrient imbalance could thus be derived probabilistically for conducting D(2) diagnosis, while the CND - r(2) nutrient imbalance threshold must be calibrated using fertilizer trials. In the proposed CND - D(2) procedure, D(2) is first computed to classify the specimen as possible outlier. Thereafter, nutrient indices are ranked in their order of limitation. The D(2) norms appeared less effective in the 1900-2100 CTU zone.

Nutrition, dry matter accumulation and partitioning and phosphorus use efficiency of potato grown at different phosphorus levels in nutrient solution

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Nutrient extraction and exportation by castor bean hybrid lyra

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Nutrient recycling and physical indicators of an alley cropping system in a sandy loam soil in the pre-Amazon region of Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Growth and development of Mentha piperita L. in nutrient solution as affected by rates of potassium

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effects of aluminum on plant growth and nutrient uptake in young physic nut plants

Aluminum (Al3+) toxicity is a major limiting factor to crop productivity in acid soils. The effects of aluminum on root and shoot growth of physic nut (Jatropha curcas L.) young plants and, the uptake and distribution of phosphorus, calcium, magnesium and aluminum in the roots and shoots were investigated in the present study. Plants were grown in 2.5L pots in a greenhouse. After fourteen days of adaptation to nutrient solution, plants were exposed to Al concentrations of 0, 370, 740, 1,100 and 1,480 mu mol L-1, corresponding to an active Al3+ solution of 13.3, 35.3, 90.0, 153.3 and 220.7 mu mol L-1, respectively. The dry matter partitioning between roots, stems and leaves, and the concentrations of P, Ca, Mg and Al in plant tissue, were measured after 75 days exposure to Al. The increasing level of Al3+ activity in solution progressively decreased the growth of the shoot and root of physic nut plants, and at the two highest active Al3+ levels, plants showed morphological abnormalities typical of the toxicity caused by this metal. Higher Al3+ activity reduced P concentrations in leaves and Ca and Mg in leaves and roots of physic nut, demonstrating the effect of Al on the uptake, transport and use of these nutrients by plants. The Al accumulated preferentially in the roots of physic nut, whereas only a small amount was transported to shoots.