Duration Of Starvation Research Articles

Influence of starvation at low temperatures on utilization of energy reserves, appetite recovery and growth character in sea bass,Dicentrarchus labrax

The effect of starvation at selected low temperatures was studied in sea bass,Dicentrarchus labrax. The work focused on proximate chemical constituents and blood glucose. Appetite and growth of starved, refed specimens were also examined. Two experimental sets were designed. In one set the fish were exposed to 3 °C, 7 °C and 11 °C and in the other to 3 °C, 8 °C and 13 °C. Survival of the fish in the experimental conditions was 99.7%. Appreciable loss in body weight occurred. The reduction was more marked in the first week. No significant difference in chemical composition occurred in the first two weeks of starvation. Prolongation of food deprivation resulted in decline of lipid content with a corresponding increase in water content. This trend was the more marked at high temperature. Liver glycogen was the most readily utilizable source of energy. Lipid yielded energy after which proteins were mobilized to save further loss of lipid. Lipid exerted a sparing role for glycogen. The preference for different energy sources depended on exposure temperature and duration of starvation, Lipid chiefly supplied the energy needs of the 3 °C test groups, whereas liver glycogen provided the calorific requirements of fish at 7 °C, 8 °C, 11 °C and 13 °C. In the 3 °C test groups gluconeogenesis occurred after 2 weeks. The products of lipid breakdown may have served as substrates for glycogen biosynthesis. High tolerance of sea bass to low temperature was attributed to high fat content and hyperglycemia. The study also pointed to the involvement of some organs other than liver in generating glucose from their glycogen stores following exhaustion of hepatic glycogen. Starvation stress at the lowest temperatures adversely affected the return of the fish's appetite and growth characters. Compensatory growth occurred in sea bass refed after starvation. The findings have implications for aquaculture management procedures.

Glucose disposal by skeletal muscle in response to re-feeding after progressive starvation

We investigated the extent to which increases in glucose utilization indices (GUIs) in individual skeletal muscles during chow re-feeding after 6 h, 24 h or 48 h starvation are related to the antecedent duration of starvation. Chow re-feeding after either acute or prolonged starvation led to an increase in glucose disposal by the muscle mass. Glucose intolerance after prolonged starvation was not associated with lower values of GUI in skeletal muscle. In both working and non-working muscles, the increment in GUI during the first 2 h of re-feeding was less after acute than after prolonged starvation. In non-working muscles the differential responses to re-feeding were due to higher GUI values after re-feeding rather than lower pre-prandial GUI values. Therefore the contribution of non-working muscles to glucose clearance is higher as the antecedent period of starvation is extended. Rates of glycogen deposition in non-working muscles after refeeding were similar to absolute values of GUI, and a strong relationship existed between measured GUI values and rates of glycogen deposition.

The starved colon—Diminished mucosal nutrition, diminished absorption, and colitis

Nutrition of colonic epithelial cells is mainly from short chain fatty acids (SCFAs) produced by bacterial fermentation in the colonic lumen. n-Butyrate contributes more carbon of oxidation to epithelial cells than glucose or glutamine from the vasculature. Incomplete starvation of colonic epithelial cells through lack of luminal SCFAs leads, in the short term, to mucosal hypoplasia with either diminished absorption or diarrhea. A chronic lack of SCFAs or complete organ starvation in conjunction with other factors leads to nutritional colitis, either "diversion colitis" or "starvation colitis." Whether predominantly diarrhea or colitis develops in mucosal malnutrition appears to depend upon the severity and duration of starvation. Ulcerative colitis may be classified as a nutritional colitis in that colonic epithelial cells are unable to utilize SCFAs reflecting epithelial starvation despite abundant SCFAs.

Refeeding after fasting in rats: effects of duration of starvation and refeeding on food efficiency in diet-induced obesity

Rats with diet-induced obesity starved for 8, 15, and 25 d lost liver and muscle glycogen, excess protein, and fat in proportion to duration of starvation. Fat-cell size decreased but fat-cell number did not. Upon refeeding, body fat was only partly restored, with further increase in adipocyte hyperplasia occurring in the starved obese rats. In contrast, fat-cell size was restored to near that of the prefasting value in the starved controls (dry-food-fed, fasted 4 d) after refeeding. With refeeding, food efficiency increased only if starvation had caused a reduction of adipocyte size below normal. Change in food efficiency was not associated with decreases in total carcass protein, specific tissue proteins, or glycogen stores but was correlated with degree of adipocyte filling. It is possible that adipose tissue status somehow modulates energy-dissipating mechanisms.

Gastric aspirates after trauma in children.

The volumes and pH of gastric aspirates obtained from 110 children (aged 1-14 years) who underwent surgery for trauma were related to the duration of pre-operative starvation and to the interval between food and injury. Aspirates were larger in children fasted for 4-6 hours than in those fasted for up to 10 hours, and were larger in children injured within 2 hours of eating than in those in whom this interval was longer (p less than 0.05). However, 19 of 39 children (49%) starved for over 8 hours had an aspirate of more than 0.4 ml/kg, as did five of 16 children (31%) injured 3 or more hours after eating. Thus, a 'safe' interval between oral intake and induction cannot be predicted. We conclude that securing the airway by prompt tracheal intubation is the safest way to manage any child who presents for emergency anaesthesia after trauma.

Rapid stimulation of calcium uptake by isolated rat enterocytes by 1,25(OH)2D3

Evidence is accumulating that 1,25(OH)2D3 may stimulate calcium transport from the intestinal lumen extremely rapidly by a mechanism which appears independent of de novo protein synthesis. To investigate this rapid action of 1,25(OH)2D3, the rate of calcium uptake by isolated enterocytes from duodena of young rats was determined in vitro as the uptake of 45Ca from 1-15 min. Prior in vitro exposure of cells to 1,25(OH)2D3 (100 pM) for 20 min significantly increased the rate of calcium uptake (p less than 0.001), an effect unaltered by 50 microM cycloheximide. Incubation with 100 pM 1-alpha-hydroxyvitamin D3 produced the same effect (p less than 0.01). In contrast, exposure to 10 pM 1,25(OH)2D3, as well as to 100 pM or to 1,000 pM 25-hydroxyvitamin D3 induced no significant change. Because both 1,25(OH)2D3 and starvation may stimulate key enzymes in polyamine metabolism, we investigated the effects of (i) difluoromethyl-ornithine (CHF2-Orn), a specific irreversible inhibitor of ornithine decarboxylase and (ii) varying the timing of feeding prior to sacrifice. Both in vitro CHF2-Orn and feeding prior to sacrifice significantly decreased the baseline rate of calcium uptake (p less than 0.05) and reduced the effect of 1,25(OH)2D3. Increased duration of starvation significantly increased the baseline rate of calcium uptake (p less than 0.02) without changing the increment in rate of calcium uptake induced by 1,25(OH)2D3. The study suggests (i) that the early action of 1,25(OH)2D3 on the influx process of intestinal calcium transport may involve a different molecular specificity from that involved in the genomic action of 1,25(OH)2D3 and (ii) that changes in polyamine metabolism may play a part in this process.

Egg production of the Arctic copepod Calanus glacialis: laboratory experiments

Egg production of single female Calanus glacialis Jaschnov fed with Thalassiosira antarctica at super-abundant concentrations (>300 μg C l-1) was determined over several weeks. Experiments were performed directly after collection from the East Greeland Current in June 1987 and 1988, and during resumed feeding after long-term starvation over 4 (October 1988), 4.5 (October 1987) and 6.5 (January 1988) mo. In addition, in June 1987, short-term starvation experiments of 5 and 15 d were conducted. Egg production was closely related to feeding in all experiments. While directly after collection eggs were produced within a few days, it took 2 wk (October 1987 and 1988) and 10 d (January 1988), respectively, to resume egg production after long-term starvation. During long-term starvation periods eggs were not laid. The decrease in total egg production with duration of starvation was due to decreasing clutch size and increasing spawning interval. In contrast, short-term starvation experiments only affected spawning interval. Interannual variability in egg production was high, with much higher clutch sizes in 1988. Average production rates in June 1988 correponded to 5% body C female-1 d-1, the maximum was 7.4% (1 274 eggs in 23 d). Carbon content of eggs was 0.40 μg egg-1. C. glacialis is well adapted to pulsed food events in the Arctic by its longevity; its ability to preserve its reproductive potential over several months; its rapid mobilization of ovaries; and by its high egg production rates. The implication of prolonged spawning capacity on life cycle studies is discussed.

Balance of Production and Consumption of ATP in Ammonium-starved Saccharomyces cerevisiae

To establish a balance between the ATP produced in catabolism and the ATP consumed in net biosynthesis of cellular components the energy metabolism of Saccharomyces cerevisiae utilizing glucose in the absence of a nitrogen source (resting cells) was studied. The following results were obtained. (i) Cell number and biomass increased 2- and 2.5-fold, respectively, during the first 8 h of ammonium starvation. After this period, both values remained constant. (ii) The rate of sugar consumption and ATP production decreased with the duration of starvation to about 20% of the original in 24 h. (iii) About 60% of the sugar consumed was fermented to ethanol and about 10% assimilated as cellular material. Of the assimilated sugar, as much as 80% was accumulated as carbohydrate. (iv) Only 15% of the total ATP produced in catabolism seems to be consumed in net biosynthesis and maintenance of intracellular pH. The fate of the remaining 85% is unknown.

Somatostatin response to glucose before and after prolonged fasting in lean and obese non-diabetic subjects

Insulin, glucagon, and somatostatin concentrations were measured in 7 lean and 7 obese non-diabetic subjects over 7 days of fasting. In addition each subject was given a 75 g oral glucose tolerance test after fasts of 12 h and 7 days. In lean subjects complete food deprivation induced a significant decrease in the circulating levels of both insulin and somatostatin, while glucagon nearly doubled by 48 h and then remained constant for the duration of starvation. Refeeding with oral glucose suppressed the increased plasma glucagon, but insulin and somatostatin responses were enhanced in comparison with the prefast values, as assessed by the integrated areas of change. In obese subjects peripheral insulin and somatostatin levels were significantly lowered, but plasma glucagon level was unchanged at the end of the starvation period. In the same group glucose-induced insulin and somatostatin release were greater than in the fed state. Suppression of plasma glucagon by glucose appeared less complete in obese than in lean subjects. It is concluded that prolonged starvation enhances D-cell responsiveness to glucose in lean and obese subjects.

Starvation and mucosal prostaglandin-E2 in gastric stress ulceration.

To determine whether starvation increases the susceptibility of the gastric mucosa to stress ulceration and whether this effect is linked to a change in the mucosal level of prostaglandin-E2 (PGE2), 100 Holtzman rats were divided into five groups and deprived of food for 0, 12, 24, 48 and 72 h. Then, ten animals within each group were stressed by cold restraint. At the end of the stress period, all these animals as well as their unstressed counterparts were killed, the number of gastric ulcers were counted, and mucosal levels of PGE2 were assayed. Fasting alone caused no ulcerations but a decrease in mucosal PGE2 during the initial 24 h (p less than .05). However, there was a subsequent increase in mucosal PGE2, possibly related to the release of free fatty acids during starvation. Starvation and stress caused a marked and consistent reduction of the mucosal PGE2 and an increase in the number of mucosal ulcerations directly related to the duration of starvation (p less than .05).

Induced variation of serotonin in Drosophila melanogaster and its relation to learning performance.

In insects the level of serotonin can be modified through the alimentary tract. Drosophila fed on chemically defined media to which has been added a synthesis inhibitor or an immediate precursor of this neurotransmitter have their serotonin level decreased or increased, respectively. (A 4- to 5-day treatment is optimal). Such treated flies, if tested in a procedure of Pavlovian conditioning, have different learning performances. With the same duration of starvation, nearly the same threshold for sucrose solutions, but different amounts of serotonin, the flies (blindly trained) showed conditioned inhibition of the tarsal (or proboscis-extension) reflex according to the amount of serotonin. The highest level of this biogenic amine gave the best performance.

Omnivorous feeding behavior of the Antarctic krill Euphausia superba

Feeding experiments were conducted at Palmer Station from December 1985 to February 1986 to examine the potential role of copepod prey as an alternative food source for Euphausia superba. Copepod concentration, copepod size, phytoplankton concentration, the duration of krill starvation and the volume of experimental vessels were altered to determine effects on ingestion and clearance rates. Krill allowed to feed on phytoplankton and copepods in 50-litre tubs showed greatly increased feeding rates relative to animals feeding in the much smaller volumes of water traditionally used for krill-feeding studies. Clearance rates on copepods remained constant over the range of concentrations offered, but clearance rates on phytoplankton increased linearly with phytoplankton concentration. Feeding rates increased when larger copepods were offered and when krill were starved for two weeks prior to experiments. Clearance rates of krill feeding on copepods were higher than, but not correlated with, their clearance rates on phytoplankton in the same vessel. E. superba may have a distinct mechanism for capturing copepods, perhaps through mechanoreception. Although our observed clearance rate of 1055 ml krill-1 h-1 indicates that krill can feed very efficiently on copepod prey, such feeding would meet less than 10% of their minimum metabolic requirements at the “typical” copepod concentrations reported for Antarctic waters. However, substantial energy could be gained if krill fed on the patches of high copepod concentrations occasionally reported during the austral summer, or if krill and copepods were concentrated beneath the sea ice during the winter or spring months. Our results, indicating efficient feeding on zooplankton and higher clearance rates on phytoplankton than previously believed, represent a step towards balancing the energy budget of E. superba in Antarctic waters.

Compositional changes in skin mucus and blood serum during starvation of trout

Changes in skin mucus and blood serum constituents of brook trout, Salvelinus fontinalis, and in skin mucus constituents of rainbow trout, Salmo gairdneri, were followed during 56 days of starvation. Starvation was accompanied by significant decreases in serum glucose, cholesterol, total protein, urea nitrogen, and total phosphorus. The metabolic consequences of starvation were reflected by changes in mucus composition, specifically in mucus ketone concentration. The concentration of ketone bodies in skin mucus, measured as acetoacetic acid, was positively related to the duration of starvation. Thus, measurement of skin mucus ketone offers promise for evaluating the nutritional status of salmonids.

Effect of starvation on copulatory activity ofErcolania nigra(Lemche, 1935) (Mollusca, Opisthobranchia, Ascoglossa)

Feeding dominates copulatory behavior in the few opisthobranchs for which behavioral hierarchies have been established. However, the influence of starvation on the dominant role has not been investigated previously. The present study investigates copulatory activity in the ascoglossan opisthobranch Ercolania nigra (Lemche) subject to varying starvation regimes. Copulatory activity of E. nigra is significantly higher in unstarved animals than in animals starved for 2h, 6h, and 24h. The decrease in copulatory activity is independent of the duration of previous starvation within the range tested (2–24 h). Copulatory behavior dominates feeding behavior in 60–80% of the cases, regardless of the duration of previous starvation. Thus the behavioral hierarchy of E. nigra differs markedly from that of the opisthobranchs previously investigated.

Acyl-CoA dehydrogenase activity in the riboflavin-deficient rat. Effects of starvation.

Riboflavin deficiency in weanling rats causes a metabolic disorder characterized by failure to oxidize fatty acids. The disorder is similar to that seen in several human diseases, some of which are responsive to pharmacological doses of riboflavin. Previous analysis of the riboflavin-deficient rat has shown that the failure of fatty acid oxidation is due to a decrease in the activity of the acyl-CoA dehydrogenases of beta-oxidation. The activity of these flavoenzymes in liver rapidly decreases when a riboflavin-deficient diet is initiated. The objectives of these experiments were to analyse the effects of starvation on liver mitochondria isolated from the riboflavin-deficient rat. Our studies show that the decreased mitochondrial fatty acid oxidation induced by riboflavin deficiency is partially reversed by starvation. The extent of this reversal is proportional to the duration of starvation. The starvation-associated increase in fatty acid oxidation is mediated by an increase in the mitochondrial short-chain acyl-CoA dehydrogenase activity. The activity of this enzyme is increased such that the ratio of short-chain acyl-CoA dehydrogenase apoenzyme to holoenzyme does not change. We conclude that short-chain acyl-CoA dehydrogenase activity is limiting for fatty acid oxidation when its activity falls below a critical point. The increased mitochondrial specific activity of short-chain acyl-CoA dehydrogenase during starvation may result from an increased availability of flavin coenzyme or an increase in enzyme catalytic efficiency.

Enzyme Markers of Maternal Malnutrition in Fetal Rat Brain

The impact of maternal starvation in late gestation on development of some enzymatic mechanisms concerned with neurotransmission and polyamine synthesis was studied in fetal rat brain. Between 17 and 20 d, acetylcholinesterase and choline acetyitransferase activity increased in fetal brains of fed dams, whereas maternal starvation from day 17 to day 20 resulted in heightened acetylcholinesterase but not choline acetyltransferase activity. Ornithine decarboxylase activity on a per-gram wet-weight basis fell between 17 and 20 d in fetal brain from fed dams. Increasing the duration of maternal starvation resulted in a progressive increase in fetal brain omithine decarboxylase. Arginine and putresine levels in the brain were lower in fetuses of starved mothers while spermidine and spermine concentrations were unchanged. Since the Km of ornithine decarboxylase for ornithine was found to vary directly with levels of putrescine in fetal brain, lower concentrations of putrescine and greater omithine decarboxylase activity in fetal brains from starved mothers suggested that levels of this enzyme may be controlled in part by putrescine. Changes in the maternal nutritional state had no effect on the activity of glutamate decarboxylase in fetal brain, and tissue levels of the product, γ-aminobutyric acid, were unchanged. Thus changes in ornithine decarboxylase and acetylcholinesterase activity in fetal brain may uniquely reflect biochemical alterations consequent to maternal starvation.

Annulate lamellae of the pancreatic exocrine cells in starved rats.

The ultrastructure of annulate lamellae in the pancreatic exocrine cells of rats starved for 3-42 days was studied. Annulate lamellae were rarely encountered in the pancreatic exocrine cells of control rats, but their incidence and size of stack was increased in those of starved rats depending on the duration of starvation, despite marked ultrastructural changes in these cells. Annulate lamellae were located in the para- or infranuclear cytoplasm of the cells and most of them were continuous with the relative normal rough endoplasmic reticulum. A close apposition in parallel was often found between the annulate lamellae and the outer nuclear envelope and occasionally pores in line with those of the nuclear membrane were observed in the lamellae of rough endoplasmic reticulum in 35- and 42-day-starved rats. An unequivocal continuity between the annulate lamellae and the nucleus and/or rough endoplasmic reticulum in pancreatic exocrine cells might be related to their origin and function.

Age and thyroid hormone as factors in the responses of BHE rats to starvation-refeeding.

The interacting effects of thyroid hormone, age, and duration of starvation on the enzyme and liver lipid responses of BHE rats to starvation-refeeding were studied. Rats were starved for 2, 4, or 7 days and refed a 65% glucose diet for 2 days. The rats were either 150 or 420 days of age and injected daily with either saline or 10 micrograms thyroxine/100 g body weight. Neither age nor duration of starvation affected the glucose-6-phosphate dehydrogenase or malic enzyme activity or liver lipid response to starvation-refeeding. However, thyroxine treatment potentiated the response to starvation-refeeding in the 420-day-old rats when the duration of starvation increased from 2 to 7 days.

The effect of starvation on the phagocytic and bacteriocidal activities in heterophils of chicks.

The effect of starvation on the rate of clearance of yeast cells was studied in 5-week-old chicks. Phagocytic and bacteriocidal activities were also investigated in the heterophils taken from abdominal cavities of chicks starved for 24 or 48 hours. The changes in peripheral leucocyte counts and plasma cortisol level indicate that chicks starved enough to be analysed of clearance rate, phagocytic and bacteriocidal activities. The phagocytic activity of heterophils assessed by per cent inhibition of 3H-uridine uptake by S.cerevisiae was unchanged or activated by starvation. In contrast with phagocytic activity, the rate of clearance in chicks and the bacteriocidal activity of heterophils were lowered by starvation. The extents of the reduction in clearance rate and of the inhibition in bacteriocidal activitywere paralleled by duration of starvation. It is concluded that the inhibitory effect of starvation on the bacteriocidal activitiy of heterophils may be a cause of the reduction in clearance rate.

イカナゴ仔魚の飢餓耐性

The ability of newly hatched larvae of the Japanese sand eel to resist starvation was studied in a rearing experiment. The starved larvae were all dead by day 14 at 15.5°C, by day 20 at 10.5°C, and by day 24 at 6.5°C. During 23 days starvation at 6.5°C, the dry weight of the larvae dccreased from 33.9μg at hatching to 22.3μg, and SL decreased from 5.57mm at complete yolk-sac absorption to 5.10mm. The percentage survival on day 24 in the delayed feeding experlment was 55% for the larvae fed from day 2, 48% for day 5, 59% for day 9, 53% for day 12, 30% for day 13, 17% for day 14, 11% for doy 15, 9% for day 16, and 9% for day 17. A clear point of no return was not found and a long duration of recoverable starvation, about 9 days, was estimated. Even some of the larvae that were fed from day 17 ingested food and grew. These results show that the toleramce of starva-tion of the sand eel larvae has a wide range and that some of the larvae have high resistance to starvation.