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Results for “dietary environments”

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PubMed1978

The influence of dietary fat levels and environmental temperature on digestible energy and absorbability of animal fat in catfish diets.

A study was conducted on the effects of three dietary levels of animal fat (5%, 10%, and 15%) and two environmental temperatures (23 and 28 degrees) on the digestible energy (DE) and apparent absorbability (AA) of animal fat in diets of 150 g catfish. Results obtained by the use of the chromic oxide indicator technique demonstrated that at 28 degrees and substitution levels up to 10% of diet, animal fat had a DE value of 7,000 kcal/kg and an AA of 94%. At the 15% level of substitution, both DE and AA were substantially reduced. At each level of substitution, DE and AA values were considerably lower in fish reared at 23 degrees. At supplemental levels up to 10% of diet, the DE and AA values for catfish at 23 degrees were 6,130 kcal/kg and 70%, respectively. Results from this study reconfirmed previous growth data which indicated that animal fat is an excellent dietary energy source for catfish which are reared at optimum temperatures.

Absorption↗
PubMed1977

Altitude tolerance in rats in relation to carbohydrates and fats in their diet.

Rats were exposed to simulated altitudes of 3658, 4877 and 7620 m, 5 h/d for 30 d, at ambient temperature of 28 degrees C. Voluntary food intake, growth rate, and survival time were measured under effects of commercial diet (50% CHO, 4% fat and 24% protein), high fat diet (52% fat), and high carbohydrate diet (75% CHO). The results showed that altitude-exposed rats on high CHO diet had improved growth rate, but lowered survival time on their subsequent exposure (at the end of a 1-month period) to severe hypoxia (5% oxygen). The animals on high fat diet had very poor growth rate, as they ate very little amount of it voluntarily, either at sea level or under high-altitude conditions. These rats, however, had tremendously increased resistance to severe hypoxia (survival time greater than 60 min as compared with greater than 12 mins of those on commercial or high CHO diet).

Altitude↗
PubMed2026

Divergent PXR function in seals: Endocrine adaptation or functional loss?

Seals accumulate xenobiotics through dietary biomagnification and exposure to polluted marine environments, with contaminants concentrating in their blubber. Biotransformation mitigates xenobiotic toxicity by converting lipophilic compounds into excretable hydrophilic metabolites, a process coordinated by nuclear receptors including the Pregnane X Receptor (PXR), whose plastic ligand-binding domain enables broad xenobiotic sensing. By examining PXR in pinnipeds, we investigated the evolutionary conservation and functional characterization of PXR using genomic sequence analysis, protein structural prediction, and transactivation assays, revealing broadly conserved structural features alongside species-specific functional divergence in receptor responsiveness to environmental stressors. Specifically, the obtained results highlight divergent gene and functional landscapes with ORF-disrupting mutations identified in Monachus monachus and Neomonachus schauinslandi that abolish receptor activation toward known PXR ligands. In contrast, Leptonychotes weddelli retained an intact PXR ORF but showed reduced receptor activity, revealing functional divergence in PXR among pinnipeds.

Biotransformation↗
PubMed2025

Enriched grain minerals in Aegilops tauschii-derived common wheat population under heat-stress environments.

In wheat (Triticum aestivum L.), an important source of dietary minerals, heat stress during the grain filling stage negatively affects grain yield and quality. Wheat grain mineral content has been primarily evaluated under optimum conditions; little information is available on the genetic variations and loci involved in mineral accumulation under heat stress. Therefore, this study aimed to assess the variation in 13-grain mineral concentrations and thousand kernel weight of 145 wheat multiple synthetic derivatives (MSD) genotypes harboring genes from the wild relative Aegilops tauschii Coss., evaluated under heat-stress field conditions in Sudan for two seasons, and to dissect the genomic regions associated with these mineral contents using GWAS. Our results showed sufficient variations in mineral concentrations among the MSD lines. Some MSD lines had 30-50% more minerals than the recurrent parent Norin 61. We detected 188 significant marker-trait associations (MTAs), 44 MTAs in season 2018/19, one in season 2019/20, and 143 based on BLUE. The highly significant, stable, and promising MTAs were related to Mg, Mn, P, and Ba. We identified putative candidate genes potentially involved in mineral movement (TraesCS5D03G0728800) and response to heat stress (TraesCS5D03G0723300). The findings in this study help to enhance mineral concentration and resilience in wheat under heat.

Triticum↗
PubMed1979

Simultaneous measurement of serum 25-hydroxycholecalciferol and 25-hydroxyergocalciferol.

A method for the selective measurement of serum 25-hydroxycholecalciferol and 25-hydroxyergocalciferol has been developed. The two hydroxysecosteroids were measured in a control group and in a group of ambulatory patients treated chronically with anticonvulsant drugs. In both groups the serum levels of 25-hydroxycholecalciferol and 25-hydroxyergocalciferol followed a log normal distribution. No significant difference could be elicited between the control and the treated groups for either hydroxysecosteroid. Furthermore the data shows how important is the dietary source of vitamin D in our environment.

Adolescent↗
PubMed1976

Casual blood pressures and their possible relation to age, body weight, Quetelet's index, serum cholesterol, percentage of body fat and mid-arm muscle circumference in three groups of northern Nigerian residents.

Blood pressures were determined for rural outpatients, soldiers and university students. There was no consistent change of systolic blood pressure with age until the sixth decade but even here, the rise could be due to the inclusion of a relatively high number of hypertensive subjects in the sample mean. Diastolic blood pressures show a steady rise with age consistent with the decreased elasticity of arteries with age. Diastolic pressures are remarkably low and probably reflect a general vasodilation necessitated by the hot day-time temperatures of this environment to facilitate heat loss and maintain body temperature. Dietary and psychological influences may also be involved. Pulse pressures are predictably high and decrease with age. Hypertension was observed in many groups although totally absent in some. Body weight significantly correlates with systolic and diastolic pressures in 13-19-year old adolescents probably because during this period of rapid growth blood pressure changes parallel changes in body build. In most other groups blood pressures show no consistent relationship with either body weight, Quetelet's index, mid-arm muscle circumference, serum cholesterol or percentage of body fat.

Adolescent↗
PubMed2025

Interaction of genetics risk score and fatty acids quality indices on healthy and unhealthy obesity phenotype.

BACKGROUND: The growth in obesity and rates of abdominal obesity in developing countries is due to the dietary transition, meaning a shift from traditional, fiber-rich diets to Westernized diets high in processed foods, sugars, and unhealthy fats. Environmental changes, such as improving the quality of dietary fat consumed, may be useful in preventing or mitigating the obesity or unhealthy obesity phenotype in individuals with a genetic predisposition, although this has not yet been confirmed. Therefore, in this study, we investigated how dietary fat quality indices with metabolically healthy obesity (MHO) or metabolically unhealthy obesity (MUO) based on the Karelis criterion interact with genetic susceptibility in Iranian female adults. METHODS: In the current cross-sectional study, 279 women with overweight or obesity participated. Dietary intake was assessed using a 147-item food frequency questionnaire and dietary fat quality was assessed using the cholesterol-saturated fat index (CSI) and the ratio of omega-6/omega-3 (N6/N3) essential fatty acids. Three single nucleotide polymorphisms-MC4R (rs17782313), CAV-1 (rs3807992), and Cry-1(rs2287161) were genotyped by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique and were combined to produce the genetic risk score (GRS). Body composition was evaluated using a multi-frequency bioelectrical impedance analyzer. Participants were divided into MHO or MUO phenotypes after the metabolic risk assessment based on the Karelis criteria. RESULTS: We found significant interactions between GRS and N6/N3 in the adjusted model controlling for confounding factors (age, body mass index, energy, and physical activity) (β = 2.26, 95% CI: 0.008 to 4.52, P = 0.049). In addition, we discovered marginally significant interactions between GRS and N6/N3 in crude (β = 1.92, 95% CI: -0.06 to 3.91, P = 0.058) and adjusted (age and energy) (β = 2.00, 95% CI: -0.05 to 4.05, P = 0.057) models on the MUH obesity phenotype. However, no significant interactions between GRS and CSI were shown in both crude and adjusted models. CONCLUSION: This study highlights the importance of personalized nutrition and recommends further study of widely varying fat intake based on the findings on gene-N6/N3 PUFA interactions.

Humans↗
PubMed1977

Nutrition and the responses to extreme environments.

The calorie requirements of adequately clothed men living and working in a cold environment are not increased, except for the 2-5 percent increase in matabolic rate due to the "hobbling" effect of the heavy clothing. The energy requirements in the cold, as in a temperate environment, are primarily a function of body weight and level of physical activity. The discrepancies between studies of persons living in a hot environment are explainable and are primarily due to the level of protection from the heat. The increased requirements are probably due to the increased heat load imposed on the body by solar radiation and the extreme heat. The increased requirements, in all likelihood, are a combination of increased action by blood in heat transport, increased ventilation and heart rate, and increased action of the sweat glands plus the increase in metabolic rate due partially to elevation in body temperature. In view of some strong new evidence, the energy requirements are increased for individuals living and working in extremely hot environments. There is no evidence showing that modification of macro nutrient composition of the diet will enhance either heat tolerance or cold adaptation in humans. Recent studies indicate that high carbohydrate diets will improve tolerance during high altitude exposure.

Animals↗
PubMed1977

Riboflavin requirement of starting chickens in a tropical environment.

Growth rate of broiler chicks tends to be lower in the tropics than in the temperate zone. Results show that up to 17% of dietary riboflavin is destroyed within 24 hours of exposure of the feed to light hence the level of 3.6 mg. of vitamin B2 recommended does not meet the requirement for growth of broilers. Growth study as well as accumulation of riboflavin in meat and organs of the birds showed that increasing levels of dietary riboflavin increases its deposition in meat and organs of the birds. Optimum growth of birds and storage of riboflavin in the body is attained in the tropical environment when 5.1 mg. of the vitamin is added per kg. of practical ration.

Animals↗
PubMedDate not supplied

Sources of lead in blood. Identification by stable isotopes.

The isotope ratios of lead in the blood of ten subjects resident in Dallas, Texas, were measured from April 1974 to June 1975. During the same period, the ratios in the city's air changed linearly by 6%. One subject gave erratic results, but the remainder yielded ratios that changed systematically--some linearly, others cyclically with turning points occurring in August to October and February to April. Two South African subjects were 6 months out of phase with their U.S.-born wives and the other U.S.-born subjects. Since the South Africans are presumed to have in their skeletons lead that is isotopically distinct from that in the U.S. environment, the cycles are attributed to the mixing of skeletal and dietary lead. The dietary component is inferred to be greatest in August to October, which correlates with the time at which 25-hydroxyvitamin D is reported to have maximum concentration in blood. On the assumption that the isotope ratios of dietary leads remained constant, the proportion of airborne lead in the blood of those subjects whose ratios changed linearly could be calculated, and values between 7 +/- 3% and 41 +/- 3% were obtained.

Adult↗
PubMed1979

Alteration of catecholamine uptake in cerebral cortex from rats fed a saturated fat diet.

The transport of [3H]norepinephrine into chopped cerebral cortex of neonates was changed by feeding pregnant rats with semisynthetic diets enriched in saturated fat (coconut oil) as compared to polyunsaturated fat (sunflower oil). There was a significant decrease in the uptake of norepinephrine in neonates from dams fed coconut oil compared to neonatal pups from animals fed sunflower oil. Differences were observed on days 7, 11, 24, and 37 but not in adults which had been maintained on the diet since birth. Kinetic analysis of norepinephrine uptake on day 7 neonates demonstrated a 5-fold increase in Km and a 2-fold increase in Vmax for the coconut oil fed group as compared to control or the sunflower oil fed rats. [3H]Dopamine uptake kinetics revealed no significant difference in day 7 neonates but a doubling of the Km and Vmax in day 37 rats and in adults fed coconut oil. Lipid analysis of cerebral cortex synaptosome membrane fractions revealed significant differences in the fatty acyl composition of the phospholipid. The results indicate that the norepinephrine and dopamine transport systems can be differentially affected by dietary lipid composition in the developing rat. It is suggested that the changes may be due to alterations in membrane fluidity in the local environment of the transport system.

Animal Feed↗
PubMed1976

[Resistance to modification of dietary behavior].

There exist certain pathological eating behaviors (they deviate from the usual eating pattern in a given environment; ex.: hyperphagia, alcoholism, bulimia, nibbling sweets, etc.): there also exist certain pathogenic, though not pathological, eating behaviors (a "normal" behavior may induce an affection in given subjects; ex.: obesity in subjects with a normal caloric intake, hypercholesterolemia in subjects with a normal lipid intake, etc.). In the perspective of Public Health, the field of pathological behavior calls for specialized individual interventions, which can sometimes serve as research models; but the field of pathogenic behavior is now such a widespread social phenomenon (50% of the female population wishes to reduce, 50% of the male population dies from alimentary-linked cardiovascular diseases) that it must be systematically investigated. Such investigations would require: 1. A typology assessing the effectiveness of all the techniques aimed at a modification of eating behavior, whether preventive or therapeutic (through information, pressure, learning); 2. A typology of the resistance to change, whether physiological, psychological or psychosocial. A study of both typologies is necessary since until now all the attempts to induce a population as a whole to renounce food plethora have been unsuccessful, except when imposed by economic or political motivations. Moreover, in a society oriented toward consuming, a change in eating behaviors must be "consumable", that is, at once adequate and gratifying, in order to be accepted.

Adult↗
PubMed1975

Food intake, its relationship to body weight and age, and its apparent nutritional adequacy in New Guinean children.

Previous nutritional investigations in New Guinea have shown low intakes of protein and of energy yet the nutritional status of children and their ability to thrive have been regarded as better than could be expected. To investigate this apparent paradox, the dietary intakes of 482 New Guinean children, aged 1-18 years, living in two contrasting environments near the coast (Kaul) and in a highland region (Lufa) were determined by a weighed individual inventory method over 5-7 consecutive days. Body weights and skinfold thicknesses were lower than those of European children of comparable ages. These findings are to be reported and discussed more fully in a separate publication. Roots and tubers provided most of the energy and protein in the bulky, vegetable diets. The contribution of foods bought in local trade stores was higher than has previously been reported. Fat intakes were low, supplying 17% of the dietary energy in Kaul and 10% in Lufa. Protein intakes were similarly low, representing only 6% of dietary energy. The chemical scores of the protein calculated using the latest suggested amino acid scoring pattern (FAO/WHO, 1973) were high, 75-95. Using the previous pattern, these were 57-64. The adequacy of the energy and protein contents of individual diets was assessed using the FAO/WHO (1973) standards. An energy deficit was more common than a protein deficit. A considerable proportion of the children (42% in Kaul and 20% in Lufa) had dietary intakes which were apparently deficient in energy or protein, but this finding did not correspond to other signs of undernutrition. This suggests that current standards may still be set too high for some groups or that adaptations to suboptimal dietary intakes occur that are not disclosed by the usual techniques of assessing nutritional status.

Adolescent↗
PubMed1979

Rhodopsin determinations in C57BL/6J-pallid strain mice.

The influence of light environment on rhodopsin concentration per eye was determined in littermate pigmented and nonpigmented C57BL/6J-pallid gene mice reared under cyclic light or continuous dark environments. Attempts to exacerbate a congenital manganese deficiency in pallid strain mice included dietary deprivation and supplementation with manganese and exposure to intense light followed by the determination of rhodopsin recovery rates in darkness. Homozygous pallid mice (pa/pa) reared in cyclic light had rhodopsin levels which were significantly lower than heterozygous (+/pa) or homozygous (+/+) black control mice. Dark-rearing resulted in a significant increase in rhodopsin per eye in pallid strain mice and equivalent levels in adult mice, but young pallid strain mice did not achieve the same rhodopsin concentration as young +/+ mice. Although dietary manganese deprivation or supplementation did not significantly alter rhodopsin levels among pallid mice, the deficient diet resulted in lower rhodopsin per eye in the young +/+ control animals. The recovery of rhodopsin in darkness following intense light exposure was equal and complete within 24 hr for most genotypes. However, recovery by pallid mice after 24 hr was significantly lower than by pigmented or albino genotypes.

Animals↗
PubMed1977

[Epidemiology of cancer and the environment].

Results of epidemiological investigations point out that environmental factors have an influence on the development of at least 80% of cancer diseases. The cancer mortality rates in Austria are analyzed with regard to this point. Austrian mortality trends of the most common malignancies are similar to those of other western industrialized countries. The relationship between cancer risk and the size of the Austrian communities is shown. As opposed to other common cancer sites, cancer of the stomach is most common in small communities with mainly an agricultural population. Etiological hypotheses about the origin of stomach cancer are discussed with regard to its epidemiological findings as well as the dietary habits of the population.

Adult↗