Dietary Sucrose Concentration Research Articles

Sugar restriction and blood ingestion shape divergent immune defense trajectories in the mosquito Aedes aegypti

Immune defense is comprised of (1) resistance: the ability to reduce pathogen load, and (2) tolerance: the ability to limit the disease severity induced by a given pathogen load. The study of tolerance in the field of animal immunity is fairly nascent in comparison to resistance. Consequently, studies which examine immune defense comprehensively (i.e. considering both resistance and tolerance in conjunction) are uncommon, despite their exigency in achieving a thorough understanding of immune defense. Furthermore, understanding tolerance in arthropod disease vectors is uniquely relevant, as tolerance is essential to the cyclical transmission of pathogens by arthropods. Here, we tested the effect(s) of dietary sucrose concentration and blood ingestion on resistance and tolerance to Escherichia coli infection in the yellow fever mosquito Aedes aegypti. Resistance and tolerance were measured concurrently and at multiple timepoints. We found that mosquitoes from the restricted sugar treatment displayed enhanced resistance at all timepoints post-infection compared to those from the laboratory standard sugar treatment. Blood also improved resistance, but only early post-infection. While sucrose restriction had no effect on tolerance, we show that consuming blood prior to bacterial infection ameliorates a temporal decline in tolerance that mosquitoes experience when provided with only sugar meals. Taken together, our findings indicate that different dietary components can have unique and sometimes temporally dynamic impacts on resistance and tolerance.

Parental dietary sucrose affects metabolic and antioxidant enzyme activities in Drosophila

ABSTRACTThe influence of parental nutrition as a key environmental factor that can influence offspring performance has become a hot topic for modern investigations. In the current study using fruit flies, Drosophila melanogaster, we found the sucrose concentration of the diet in the parental generation had a significant influence on the metabolism and antioxidant defense of the next generation, even when that subsequent generation had been shifted to a standard diet. We found that low concentrations of dietary carbohydrate in the parental generation led to higher activities of lactate dehydrogenase, malate dehydrogenase (MDH) and alanine transaminase (ALT) enzymes and increased urea content in their progeny. Moreover, higher activities of the first‐ and second‐line antioxidant defense enzymes were detected in F1 males generated from parents fed a low‐carbohydrate diet. Low sucrose concentration in the parental diet resulted in increased levels of protein thiols but decreased the low‐molecular‐weight thiol group content in F1 males. The influence of different dietary sucrose concentrations also resulted in sex‐dependent differences, where MDH, ALT, glutathione‐S‐transferase, glucose‐6‐phosphate dehydrogenase and isocitrate dehydrogenase activities and levels of thiol groups were unaffected in F1 females. The results highlight the transgenerational influence that specific dietary macronutrients provided in the parental diet, namely carbohydrates, can have on the next generation, influencing enzyme activities, metabolic pathways and antioxidant defenses in progeny Drosophila.

Evaluation of the Impact Induced by High Dietary Sucrose Concentration and Glucocorticoid Medication on Dentin Formation of Young Rats

The impact of sucrose and systemic cortisone treatment on the response of dentin was examined in an experimental rat model. After 2 months of a modified diet and/or medication period, the areas of dentin formation and dentinal caries were quantified in the mandibular molars of growing animals. The 60% sucrose diet significantly reduced dentin formation and increased dentinal caries progression. The presence of glucocorticoid medication alone reduced dentin formation. Cortisone medication in combination with sucrose diet further decreased dentin apposition. Rats receiving the control diet positively responded to the dentinal caries by increasing dentin formation to prevent pulpal exposure. The rate of dentine formation was lower in rats with high sucrose diet and predentin area was wider compared to the control group fed normal diet. The enlargement of the predentin region in sucrose diet rats reflects changes in the functionality of the odontoblasts, such as reduction of matrix synthesis and alteration of the mineralization process. These results indicate that the functional alterations in the pulpo-dentinal complex might contribute to dentinal caries progression through systemic mechanism irrespective of the causative factors.

Evaluation of the Impact Induced by High Dietary Sucrose Concentration and Glucocorticoid Medication on Dentin Formation of Young Rats

The impact of sucrose and systemic cortisone treatment on the response of dentin was examined in an experimental rat model. After 2 months of a modified diet and/or medication period, the areas of dentin formation and dentinal caries were quantified in the mandibular molars of growing animals. The 60% sucrose diet significantly reduced dentin formation and increased dentinal caries progression. The presence of glucocorticoid medication alone reduced dentin formation. Cortisone medication in combination with sucrose diet further decreased dentin apposition. Rats receiving the control diet positively responded to the dentinal caries by increasing dentin formation to prevent pulpal exposure. The rate of dentine formation was lower in rats with high sucrose diet and predentin area was wider compared to the control group fed normal diet. The enlargement of the predentin region in sucrose diet rats reflects changes in the functionality of the odontoblasts, such as reduction of matrix synthesis and alteration of the mineralization process. These results indicate that the functional alterations in the pulpo-dentinal complex might contribute to dentinal caries progression through systemic mechanism irrespective of the causative factors. Keywords: diet, sucrose, cortisone, dentin

Dietary Modulation of Drosophila Sleep-Wake Behaviour

BackgroundA complex relationship exists between diet and sleep but despite its impact on human health, this relationship remains uncharacterized and poorly understood. Drosophila melanogaster is an important model for the study of metabolism and behaviour, however the effect of diet upon Drosophila sleep remains largely unaddressed.Methodology/Principal FindingsUsing automated behavioural monitoring, a capillary feeding assay and pharmacological treatments, we examined the effect of dietary yeast and sucrose upon Drosophila sleep-wake behaviour for three consecutive days. We found that dietary yeast deconsolidated the sleep-wake behaviour of flies by promoting arousal from sleep in males and shortening periods of locomotor activity in females. We also demonstrate that arousal from nocturnal sleep exhibits a significant ultradian rhythmicity with a periodicity of 85 minutes. Increasing the dietary sucrose concentration from 5% to 35% had no effect on total sucrose ingestion per day nor any affect on arousal, however it did lengthen the time that males and females remained active. Higher dietary sucrose led to reduced total sleep by male but not female flies. Locomotor activity was reduced by feeding flies Metformin, a drug that inhibits oxidative phosphorylation, however Metformin did not affect any aspects of sleep.ConclusionsWe conclude that arousal from sleep is under ultradian control and regulated in a sex-dependent manner by dietary yeast and that dietary sucrose regulates the length of time that flies sustain periods of wakefulness. These findings highlight Drosophila as an important model with which to understand how diet impacts upon sleep and wakefulness in mammals and humans.

Sweet problems: insect traits defining the limits to dietary sugar utilisation by the pea aphid,Acyrthosiphon pisum

Plant phloem sap is an extreme diet for animals, partly because of its high and variable sugar content. The physiological and feeding traits of the pea aphid Acyrthosiphon pisum that define the upper and lower limits to the range of dietary sucrose concentrations utilised by this insect were determined principally using chemically defined diets containing 0.125-1.5 mol l(-1) sucrose. On the diets with 0.125 mol l(-1) and 1.5 mol l(-1) sucrose, the aphids died as larvae within 8 and 14 days of birth, respectively. On the other diets, 60-96% of aphids developed to adulthood, and the 0.5 mol l(-1) and 0.75 mol l(-1) diets supported the highest fecundity. The diet with 0.125 mol l(-1) sucrose was ingested at 36% of the rate of the 0.25 mol l(-1) sucrose diet, but >90% of ingested sucrose-carbon was assimilated on both diets. This suggests that the lower limit is dictated by the aphid feeding response, specifically, a requirement for a minimal concentration of sucrose for sustained feeding. The haemolymph osmotic pressure of aphids on diets with 0.125-1.5 mol l(-1) sucrose was up to 68% higher than on 0.125-1.0 mol l(-1) sucrose diets, but diet consumption and sucrose-carbon assimilation was not reduced on the very high sucrose diets relative to 1.0 mol l(-1) sucrose. This suggests that failure of the osmoregulatory capacity of the insects on high sucrose diets may define the upper limit to the range of dietary sucrose utilised by the aphids. The mean haemolymph osmotic pressure of aphids on plants with phloem sap containing 0.37-0.97 mol l(-1) sucrose was 1.61+/-0.063 MPa (mean +/- s.e.m.), not significantly different from that (1.47+/-0.059 MPa) on diets with 0.25-1.0 mol l(-1) sucrose. It is concluded that the osmoregulatory response of aphids to diets and plants are comparable, and, more generally, that the feeding and osmoregulatory capabilities of the aphids are compatible with the phloem sugar levels commonly encountered by aphids feeding on plants.

Effects of temperature and dietary sucrose concentration on respiration in the silverleaf whitefly, Bemisia argentifolii

A system consisting of a flow-through chamber connected to a commercial infrared gas analysis system was developed to measure homopteran respiration during feeding. Using this system, respiration rates of 202 and 206 μmol CO 2 h −1 g −1 (4.96 and 5.04 ml CO 2 h −1 g −1) were determined for whiteflies and cotton aphids, respectively, at 25°C on diets containing 15% sucrose. These rates were considerably higher than those of other stationary insects, indicating that whiteflies and aphids maintain a relatively high metabolic rate when feeding. Whitefly respiration increased with temperature from 25 to 46°C with a Q 10 of about 2 on diets containing 10, 15 and 20% sucrose, but less than 2 on diets containing 2.5 and 5% sucrose. Respiration rates were similar on the diets containing >10% sucrose, but were generally lower on the diets containing <10% sucrose. Respiration rates decreased upon extended exposure to 47°C; the rate of decrease was inversely related to the dietary sucrose concentration up to 15%. The results indicate that whiteflies require a sucrose concentration of between 5 and 10% (i.e. 0.15 and 0.3 M) for maximum rates of metabolism while feeding. Higher concentrations of sucrose in the diet delayed high-temperature mortality, possibly a reflection of the high sucrose requirement for sorbitol synthesis in whiteflies.

Differential effects of fat and sucrose on body composition in [formula omitted] and C57BL/6 mice

The C57BL/6 (B6) mouse is more sensitive to the effects of a high-fat diet than the A J strain. The B6 mouse develops severe obesity, hyperglycemia, and hyperinsulinemia when fed this dietary regimen. This study was conducted to determine the effects of dietary fat and sucrose concentrations on body composition and intestinal sucrase (EC 3.2.1.48) and maltase (EC 3.2.1.20) activity in these two mouse strains. High-fat diets, regardless of sucrose content, resulted in significant weight gain, higher body fat, and lower body protein and water content in both strains of mice. The shift toward higher body fat and lower protein and water content was far greater in the B6 strain. Low-fat, high-sucrose diets resulted in lower body weight in both strains, as well as significantly greater body protein content in B6 mice. Analysis of intestinal sucrase showed that the enzyme was less active in B6 mice when the diet was high in sucrose. Both sucrase and maltase had lower activity in the presence of high dietary fat in both mouse strains. The percent reduction of intestinal enzyme activity due to dietary fat was similar in both strains. The B6 mouse exhibits disproportionate weight gain and altered body composition on a high-fat diet. This coupled with the reduced body weight and increased body protein on a low-fat, high-sucrose diet suggests that factors-relative to fat metabolism rather than sucrose metabolism are responsible for obesity.

A thermoprotective role for sorbitol in the silverleaf whitefly, Bemisia argentifolii

Accumulation of polyols in insects is well known as a cold-hardening response related to overwintering or to protection against cold shock. The silverleaf whitefly ( Bemisia argentifolii, Bellows and Perring) is a major insect pest in tropical and subtropical regions where heat stress and desiccation pose formidable threats to survival. We found that sorbitol levels increased ten-fold when whiteflies were exposed to elevated temperatures. Sorbitol levels rose from 0.16 nmol whitefly −1 at 25°C to 1.59 nmol whitefly −1 at 42°C. Sorbitol levels fluctuated diurnally under glasshouse and field conditions increasing ten-fold from morning to early afternoon. Feeding experiments on artificial diets showed that both temperature and dietary sucrose concentration were key factors influencing sorbitol accumulation. Cell free extracts prepared from adult whiteflies catalyzed NADPH-dependent fructose reduction, but were unable to reduce glucose with either NADPH or NADH. Radiotracer experiments with labeled glucose and fructose showed that fructose was the immediate precursor of sorbitol. Thus, sorbitol synthesis in the whitefly is apparently unconventional, involving conversion of fructose by a novel NADPH-dependent ketose reductase. We propose that sorbitol accumulation is a mechanism for thermoprotection and osmoregulation in the silverleaf whitefly, allowing the insect to thrive in environments conducive to thermal and osmotic stress.

Dietary sucrose and oligosaccharide synthesis in relation to osmoregulation in the pea aphid, Acyrthoslphon pisum

Abstract. A major problem for aphids is the avoidance of dehydration due to a high dietary osmotic pressure. Their adaptations include a high osmotic pressure in the haemolymph and polymerization of dietary sugars to oligosaccharides. The pea aphid, Acyrthosiphon pisum (Harris), was fed on an artificial diet containing Relabelled sucrose, and the fate of dietary sucrose was studied using quantitative paper chromatography. The haemolymph of A. pisum, feeding on artificial diet containing 25% w/v (730 mM) sucrose, contained two main sugars: trehalose (255 nw) and fructose (129 mM). No sucrose was found in the haemolymph. The honeydew sugars (350 mM) of aphids fed the same diet were mainly oligosaccharides (220 mM). The polymerization of sucrose was responsible for a 34% reduction in molarity of sugars in the honeydew. At low dietary sucrose concentrations, the honeydew contained mainly mono‐ and disaccharides. At dietary sucrose concentrations of 15% or more, oligosaccharides were predominant. This is consistent with the idea that osmoregulation is carried out by oligosaccharide synthesis. Analysis of the stomach contents revealed that oligosaccharide synthesis occurs there, and tissue incubation showed that die gut is much more active in oligosaccharide synthesis than the eviscerated body tissues. The function of the filter chamber, found in some aphid species, is considered and it is suggested that this is a mechanism for reducing the osmotic pressure of the ingested diet.

Greater Concentration of Dietary Sucrose Decreases Dentin Formation and Increases the Area of Dentinal Caries in Growing Rats

The effect of increasing dietary sucrose concentration on dentin formation and dentinal caries progression was studied. Weanling Wistar rats received 15, 30 or 43 g/100 g sucrose in a diet; for reference, another group was fed a nonpurified diet. At the onset, tetracycline was injected to mark the dentin formed during the experiment. After 6 wk, lower molars were sectioned sagittally; the areas and thicknesses of the dentin formation during the experiment and dentinal caries lesions were quantified separately in the first and second molars. Feeding the 43% sucrose diet resulted in a significantly lower dentin formation than in other diet groups (P< 0.05). The differences obtained from the area measurements were supported by thickness measurements. In the first molar, the 43% sucrose diet resulted in a significantly greater area of dentinal caries than in the other sucrose groups. The number and severity of caries lesions clearly increased as the concentration of sucrose in the diet increased (r= 0.5, P< 0.05 and r= 0.6, P< 0.05, respectively). This study suggests that the increase in the concentration of sucrose in the diet reduces dentin formation and increases the area of dentinal caries as well as the number and severity of caries lesions; the critical sucrose concentration appears to be between 30 and 43 g/100 g.

Honeydew sugars and osmoregulation in the pea aphid Acyrthosiphon pisum

Pea aphids, Acyrthosiphon pisum, containing their symbiotic bacteria (untreated aphids) and experimentally deprived of their bacteria by treatment with the antibiotic rifampicin (antibiotic-treated aphids) were reared on the plant Vicia faba. The sugars in the honeydew produced by untreated aphids comprised predominantly the monosaccharides glucose and fructose, while the honeydew of antibiotic-treated aphids contained considerable amounts of oligosaccharides of up to 16 hexose units. The honeydew and haemolymph of the aphids were iso-osmotic, and their osmotic pressure was significantly lower in untreated aphids (0.91&shy;0.95 MPa) than in antibiotic-treated aphids (1.01&shy;1.05 MPa) (P<0.05). For insects reared on chemically defined diets containing 0.15&shy;1.0 mol l-1 sucrose (osmotic pressure 1.1&shy;4.0 MPa), the osmotic pressure of the aphid haemolymph did not vary with dietary osmotic pressure, but was regulated to approximately 1.0 MPa in untreated and 1.3 MPa in antibiotic-treated aphids. The sugars in the aphid honeydew varied with dietary sucrose concentration; with monosaccharides dominant at low concentrations and oligosaccharides dominant at high concentrations of dietary sucrose. The lowest dietary sucrose concentration at which honeydew oligosaccharides were detected was 0.2 mol l-1 for the antibiotic-treated aphids and 0.3 mol l-1 for untreated aphids. These data indicate that the aphid, and not its associated microbiota, mediates the synthesis of oligosaccharides when the osmotic pressure of the ingesta is high.

Effect of sucrose concentration on carbohydrate metabolism in Bemisia argentifolii: Biochemical mechanism and physiological role for trehalulose synthesis in the silverleaf whitefly

Uptake and metabolism of sucrose by adult silverleaf whiteflies ( Bemisia argentifolii) were investigated on defined diets containing sucrose concentrations from 3 to 30% ( w v ). At an optimal pH of 7, the volume of liquid ingested decreased with increasing dietary sucrose concentration, but the amount of sucrose ingested showed a net increase. Above a dietary sucrose concentration of about 10%, a greater amount of the ingested carbon was excreted by the whiteflies than was retained, and the proportion that was excreted increased progressively with increasing dietary sucrose concentration. Carbohydrate analysis showed that the composition of excreted honeydew changed from predominantly glucose and fructose at low dietary sucrose concentrations to predominantly trehalulose at high concentrations, with little change in the proportion of larger oligosaccharides. Measurements of whitefly trehalulose synthase and sucrase activities revealed that the enzymatic potential for metabolizing sucrose shifted from favoring sucrose hydrolysis at low sucrose concentrations to sucrose isomerization at high sucrose concentrations. Thus, the amount of trehalulose synthesized by the silverleaf whitefly was directly related to the properties of trehalulose synthase and sucrase and the concentration of sucrose in the diet. We propose that trehalulose is synthesized for excretion when the carbon input from sucrose is in excess of metabolic needs.

Uptake, excretion and respiration of sucrose and amino acids in the pea aphid Acyrthosiphon pisum

Ingestion, excretion and respiration in aphids were studied using artificial diets labelled with radioactive sucrose or amino acids. The rate of ingestion of a 25 % w/v sucrose diet was 12.4 nl mg-1 h-1 and the honeydew excretion rate was 5.3 nl mg-1 h-1, about 43 % of the volume ingested during the same period. The concentration of sugars in the honeydew was equivalent to 0.53 mol l-1 sucrose and 69 % of the sucrose ingested was assimilated. The amino acid concentration of honeydew was 24.6 mmol l-1 and 94 % of the ingested amino acids were assimilated. Respiration was measured by collecting respired 14CO2 using a chamber which allowed the aphids to feed during the experiments on 14C-labelled artificial diets. While feeding on a 25 % w/v sucrose diet, sucrose was respired at the rate of 1.32x10(-6) mmol mg-1 h-1, equivalent to 0.354 &micro;l O2 mg-1 h-1, which was 14.6 % of the rate of ingestion. There was no evidence that reducing the dietary sucrose concentration from 22 to 11 % w/v had any effect on the rate at which sucrose was respired. Amino acids were respired at a rate of 0.14x10(-6) mmol mg-1 h-1, which was 6.4 % of the rate of ingestion. Dietary sucrose was oxidised in preference to amino acids.

Natural Transmission ofStreptococcus sobrinusin the rat: Sucrose is not an Ecological Determinant for Colonisation

In this study a natural transmission model was employed to determine the role of sucrose as an ecological determinant in the colonisation of Streptococcus sobrinus . This experimental model was designed to resemble more closely the acquisition of mutans streptococci by human infants than is possible with artificial oral inoculation/superinfection invariably employed in rodent models. Sixty donor rats were infected intraorally with S. sobrinus 67I5. Each infected donor was caged with an uninfected recipient rat. Five groups of 12 donor-recipient pairs were fed diets containing either 0, 0.1, 1, 5 or 56 per cent sucrose and their levels of colonisation with S. sobrinus were monitored daily. Transmission of S. sobrinus from donor to recipient rats occurred at all dietary sucrose concentrations including those recipients consuming no sucrose (56 per cent raw corn starch). With the single exception of recipient rats fed 56 per cent sucrose, colonisation and dental caries scores were independent of dietary sucrose. Keywords: Streptococcus sobrinus ; Natural transmission; Colonisation; Sucrose.

Effects of dietary sucrose concentration on aphid honeydew carbohydrate levels and rates of excretion

AbstractHoneydew droplets freshly excreted by two aphid species, Myzus persicae (Sulz.) and Acyrthosiphon pisum (Harr.), feeding on nutritionally adequate, artificial diets containing 10–40% w/v sucrose, were collected in oil. The volume, frequency of excretion, and carbohydrate content of the droplets were determined by measuring the diameter of the droplets in the oil, by recording the number of droplets excreted per aphid per hour, and by using a quantitative colorimetric method for estimating carbohydrates. Rates for the intake or excretion of fluid, the intake and absorption of sucrose, and the excretion of carbohydrate were consequently calculated for the two species on each dietary sucrose concentration. The percentage of dietary sucrose absorbed by the aphids ranged from 36% on diet with 40% sucrose to 97% on diet with 10% sucrose. Such honeydew/diet relationships may allow one to use honeydew carbohydrate concentrations to estimate the sucrose concentrations of the phloem sap ingested by aphids feeding on host plants.RésuméLa teneur en glucides du miellat et le taux d'excrétions chez des aphides nourris sur différentes concentrations de saccharoseDes gouttelettes de miellat fraîchement excrétées par deux espèces de pucerons, Myzus persicae (Sulz.) et Acyrthosiphon pisum (Harr.), pucerons nourris sur des régimes nutritifs synthétiques contenant 10–40% de saccharose, ont été récupérées dans de l'huile. Le volume des gouttelettes a été déterminé en mesurant leur diamètre individuel dans l'huile, la fréquence d'excrétion établie par le nombre de gouttelettes excrétées par puceron par heure, et la teneur en glucides par une méthode d'analyse colorimétrique quantitative. Les taux d'ingestion et d'excrétion de liquide, d'ingestion et d'absorption de saccharose ainsi que les taux d'excrétion de glucides ont été par la suite calculés pour les deux espèces d'aphides nourris sur les différentes concentrations de saccharose. Le pourcentage de saccharose alimentaire absorbé par les aphides a été de 36% sur le régime contenant 40% de ce glucide, mais s'est élevé à 97% sur le régime ne contenant que 10% de saccharose. D'après ces relations miellat/régime nutritif, et en connaissant la teneur du miellat en glucides, on peut faire une approximation de la concentration du saccharose dans la sève élaborée du phloème ingérée par les aphides.

Dietary sucrose and oestradiol concentration in young men.

The dietary sugar of 15 young men was reduced from their habitual approximately 150 g/day to about 55 g/day. After 3 weeks, the concentration of oestradiol in their plasma fell by about 25%. Resumption of their habitual intake of sugar for 2 weeks restored the oestradiol concentration to its previous value. The results provide further evidence that dietary sugar can be one of the causes of coronary heart disease, and support the view that the underlying mechanism producing the disease is a disturbance in hormone balance.

Sucrose‐dependent increase in oligosaccharide production and associated glycosidase activities in the potato aphid Macrosiphum euphorbiae (Thomas)

AbstractOsmotic stress due to high sucrose concentration was imposed on the potato aphid, Macrosiphum euphorbiae (Thomas), in an artificial diet situation. Thin layer chromatography resolved melezitose and six additional honeydew oligosaccharides. Significantly higher levels of these oligosaccharides were recovered from the honeydew of this species in response to feeding on increased dietary sucrose concentrations, pointing to an osmoregulatory response. In addition, carbohydrase activities from the potato aphid were described. A degree of specificity toward hydrolysis of the sucrose substrate over other α‐glucosyl sugars was demonstrated. Also, sucrose was optimal for the formation of the oligosaccharides. A strong α‐galactosidase activity was found and transgalactosylation ability was indicated. These major trends in carbohydrase activity were also found in the foxglove aphid, Acyrthosiphon solani (Kaltenbach), and the oleander aphid, Aphis nerii Fonscolombe.

Hepatic steatosis in rats fed diets with varying concentrations of sucrose

The role of dietary sucrose concentrations in the development of hepatic steatosis in rats was investigated. Twelve groups of weanling male Sprague-Dawley rats received semipurified diets with different sucrose concentrations ranging from 20 to 50% ( w w ); one group received a cereal-based chow diet. Rats were sacrificed after 3 weeks and body weight, liver/body weight ratio, plasma alanine aminotransferase concentration, hepatic triglyceride concentration, and liver morphology (light and electron microscopy) were determined. Body weight and liver/body weight ratio were decreased in rats receiving 40–50 or 25–35% dietary sucrose compared to rats receiving 20% sucrose or chow. Plasma alanine aminotransferase concentrations were within normal limits. Hepatic triglyceride concentration was significantly increased in rats receiving 40–50 and 25–35% dietary sucrose compared to rats receiving 20% dietary sucrose or chow. Light microscopy showed hepatic steatosis in a periportal distribution at all concentrations of dietary sucrose. Both the frequency and the severity of the steatosis were increased with increasing dietary sucrose concentrations. Electron microscopy from selected livers with increased hepatic triglyceride concentrations revealed increased lipid spheres and increased smooth endoplasmic reticulum without prominent Golgi apparatus or GERL complex. It is concluded that high dietary sucrose concentrations are responsible for the development of hepatic steatosis. Semipurified diets with high dietary sucrose concentrations such as the AIN-76A diet (50% sucrose) should not be used in animal studies in which increased triglyceride deposition could influence experimental outcome.

Hepatic Steatosis in Rats Fed Diets with Varying Concentrations of Sucrose

Hepatic Steatosis in Rats Fed Diets with Varying Concentrations of Sucrose. BACON, B. K., PARK, C. H., FOWELL, E M., AND MCLAREN, C. E (1984). Fundam. Appl. Toxicol. 4, 819–826. The role of dietary sucrose concentrations in the development of hepatic steatosis in rats was investigated. Twelve groups of weanling male Sprague-Dawky rats received semipurified diets with different sucrose concentrations ranging from 20 to 50% (w/w); one group received a cereal-based chow diet Rats were sacrificed after 3 weeks and body weight, liver/body weight ratio, plasma alanine aminotransferase concentration, hepatic triglyceride concentration, and liver morphology (light and electron microscopy) were determined. Body weight and liver/body weight ratio were decreased in rats receiving 40–50 or 25–35% dietary sucrose compared to rats receiving 20% sucrose or chow. Plasma alanine aminotransferase concentrations were within normal limits. Hepatic triglyceride concentration was significantly increased in rats receiving 40–50 and 25–35% dietary sucrose compared to rats receiving 20% dietary sucrose or chow. Light microscopy showed hepatic steatosis in a periportal distribution at all concentrations of dietary sucrose. Both the frequency and the severity of the steatosis were increased with increasing dietary sucrose concentrations. Electron microscopy from selected livers with increased hepatic triglyceride concentrations revealed increased lipid spheres and increased smooth endoplasmic reticulum without prominent Golgi apparatus or GERL complex. It is concluded that high dietary sucrose concentrations are responsible for the development of hepatic steatosis. Semipurified diets with high dietary sucrose concentrations such as the AIN-76A diet (50% sucrose) should not be used in animal studies in which increased trigtyceride deposition could influence experimental outcome.