Changes in metabolite concentration in the plasma, liver and muscle of feed restricted Japanese quail exposed to cold.

Quail fed ad libitum and 50% ad libitum were cold exposed for several weeks, during time control quail remained at 21 degrees C. The concentration of plasma glucose, FFA, and uric acid, tissue glycogen and carcass fat content was measured at the end of the cold exposure period. Quail fed ad libitum showed no significant change in the levels of plasma and tissue metabolites, or the carcass fat content, following cold exposure. The feed consumption by the cold exposed quail increased, and the mean body weight showed little variation from that of the controls. Feed restricted quail which were cold exposed lost significantly more weight, and had a lower ranked fat content than their controls. Whereas feed restriction caused a lowering of the liver glycogen concentration in both treatment groups, muscle glycogen levels were higher than in quail fed ad libitum. However, cold exposure was not accompanied by a change in muscle and liver glycogen levels in feed restricted quail. Feed restricted quail at 21 degrees C were hypoglycaemic and hyperlipaemic compared to quail fed ad libitum, but cold exposed feed restricted quail had a much higher plasma glucose concentration than the controls. The ranked carcass fat content was inversely related to plasma FFA level in both control and cold exposed feed restricted quail. It is suggested that both a glycolytic and lipid mobilizing response to cold is obtained in quail whose body reserves are not spared from catabolism by adequate dietary nutrient absorption, and the possibility of gluconeogenesis from precursors produced by proteolysis is indicated.     

Effect of food restriction on cold adaptability of rats

To determine the role of the nutritional state in nonshivering thermogenesis during cold adaptation, cold adaptability was compared between cold-adapted (5 degrees C for 4-5 weeks) rats fed ad libitum and cold-adapted rats pair fed with warm controls having the same food intake. Cold-adapted pair-fed rats suffered a significant loss in body weight during cold exposure. However, brown adipose tissue (BAT) in both cold-adapted ad libitum fed and cold-adapted pair-fed rats was enlarged to the same extent as compared with that in control rats. Fat-free dry matter in BAT also increased in cold-adapted ad libitum fed and cold-adapted pair-fed rats to the same extent. Cold tolerance as assessed by the change in the colonic temperature at -5 degrees C was improved relative to control rats and was the same for cold-adapted ad libitum fed and cold-adapted pair-fed rats. Nonshivering thermogenesis as estimated by the noradrenaline-induced increase in oxygen consumption was significantly greater in the cold-exposed rats and there was no significant difference between cold-adapted ad libitum fed and cold-adapted pair-fed rats. These results suggest that an improved cold tolerance by means of nonshivering thermogenesis in brown adipose tissue is closely related to the low temperature itself but not the increased food intake which occurred in the cold.     

Cleavage site of a major yolk protein (MYP) determined by cDNA isolation and amino acid sequencing in sea urchin,Hemicentrotus pulcherrimus

The grey mouse lemur (Microcebus murinus) is a small nocturnal primate exhibiting daily torpor. In constant ambient temperature (22-24 degrees C), body temperature (Tb) and locomotor activity were monitored by telemetry in animals exposed to short (SP: 10 h light/day) or long (LP: 14 light/day) photoperiods. They were first fed ad libitum for 8 days and then subjected to 80% restricted feeding for 8 more days. During ad libitum feeding, locomotor activity was significantly lower in SP-exposed animals than in LP-exposed animals. Whatever the photoperiod, animals entered daily hypothermia within the first hours following the light onset. Depth of daily hypothermia increased irregularly under SP exposure, whereas minimal daily Tb was constantly above 35 degrees C under LP exposure. After the transfer from long photoperiod to short photoperiod corresponding to the induction of seasonal fattening, locomotor activity and depth of controlled daily hypothermia did not change significantly. In contrast, food restriction led to a significant increase in locomotor activity and in frequency of daily torpor (Tb<33 degrees C) and body temperature reached minimum values averaging 25 degrees C. However, SP-exposed animals exhibited lower minimal daily Tb and higher torpor duration than LP exposed animals. Therefore, daily torpor appears as a rapid response to food restriction occurring whatever the photoperiod, although enhanced by short photoperiod.     

Resistance of hepatic glycogen to depletion in obese Zucker rats

Glycogen stores (liver and carcass) have been studied in lean and obese Zucker rats. The animals were submitted to one of three feeding conditions: ad libitum, a 48-h fast, or a 48-h fast and food ad libitum for 24 h, and to two environmental conditions, either thermoneutrality or an acute cold exposure (2 days at 4-7 degrees C). After a 2-day fast at 25 degrees C, the liver glycogen store was reduced by 45 times in the lean rats, while it was decreased by only 3 times in the obese rats. Under these conditions, the liver glycogen store was 45 times higher in the obese than in the lean rats. After 2 days in the cold, liver glycogen store was 4.4 times higher in obese rats than in lean rats. After a 2-day fast in the cold, the liver glycogen store in the obese rats was 30 times higher than in the lean rats. In comparison to fasting at thermoneutrality, fasting in the cold did not lead to a further reduction in hepatic glycogen in obese Zucker rats. The differences observed in the mobilization of the hepatic glycogen store between obese and lean rats have not been found in the mobilization of the carcass glycogen store. Drastic conditions, such as a 2-day fast in the cold, did not exhaust the glycogen store in obese Zucker rats. The present observations point out that obese Zucker rats cannot mobilize the entire hepatic glycogen store, as seen in lean control rats. The role of this abnormality in the high hyperlipogenesis that maintains the obese state is still to be evaluated.     

Effect of sex and season on the production and deposition of lipid and glycid reserves in the intermittently starving golden hamster.

In golden hamster adapted to intermittent starvation (with access to food for 3 days a week only), the glycogen and lipid content of the liver, total body fat and RQ values measured in vivo were investigated. These parameters were studied in dependence on the duration of the adaptation period (6 weeks versus 20 weeks), season of the year (winter versus summer) and sex. The liver glycogen content in intermittently starved males and females increases after 6 weeks of adaptation during winter. In summer an increase was found after long-term adaptation, but only in males. Male hamsters also exhibited a higher ability to accumulate liver lipids during both seasons. In spite of their lower weight intermittently starving males have a higher percentage of body fat in comparison with females, a stimulating effect being observed in winter. Increased lipogenesis in golden hamsters adapted to intermittent starvation may be concluded from the increased RQ values when compared with relative data gained in controls fed daily ad libitum. Significant differences between RQ measurements according to season and sex were not found.     

Influence of fasting on glycogen depletion in rats during exercise

We recently observed that a 24-h fasted group of rats could run longer than an ad libitum fed control group before becoming exhausted. Because of the demonstrated importance of glycogen levels and free fatty acid availability during endurance exercise, we have investigated several parameters of carbohydrate and lipid metabolism in exercised and nonexercised rats that were either fed ad libitum or fasted for 24 h. A 24-h fast depleted liver glycogen, lowered plasma glucose concentration, decreased muscle glycogen levels, and increased free fatty acid and beta-hydroxybutyrate concentrations in plasma. During exercise the fasted group had lower plasma glucose concentration, higher plasma concentration of free fatty acids and beta-hydroxybutyrate, and a lower muscle glycogen depletion rate than did the ad libitum fed group. Since fasted rats were able to continue running even when plasma glucose had dropped to levels lower than those of fed-exhausted rats, it seems unlikely that blood glucose level, per se, is a factor in causing exhaustion. These results suggest that fasting increases fatty acid utilization during exercise and the resulting "glycogen sparing" effect may result in increased endurance.     

Reproductive responses to variation in temperature and food supply by house mice: II. Lactation

Lactating HS/Ibg house mice housed at 21 degrees C and 5 degrees C were assigned to 3 feeding regimes: ad libitum, daily rations of 80% of ad libitum, or 60% of ad libitum beginning on the day that they bore litters. Significant interaction between temperature and food restriction was found for litter survivorship, pup survivorship, litter size, female body weight, and cumulative biomass production. The interaction was due to a magnification of the effects of food restriction at the colder temperature: i.e. mice fed ad libitum were similar at the two temperatures, mice fed the 80% ration differed, and mice fed the 60% ration differed to a greater extent. The dominant response to food restriction was cannibalism by females, which might be associated with the rate of loss in body weight by the female on the days preceding cannibalism of one or more pups. Incidents of cannibalism tended to involve a limited number of pups and to be repeated until a sustainable litter size was reached. In 3 of the food-restricted treatments, females weaned relatively large litters of relatively small pups, but in the most severe treatment (in the group fed the 60% ration at 5 degrees C), the females weaned small litters of large pups. The patterns of cannibalism and variable relative investment in individual pups reflect the aggressive breeding strategy of this classic colonizing species.     

Relative value of light and food as synchronizers of liver phosphorylase circadian rhythm.

The role played by light and feeding schedules on the circadian rhythm of glycogen content and phosphorylase activity of the liver has been studied. In one experiment, mice were subjected to a regimem of constant darkness during 21 days and compared with mice kept in 12 hrs of light alternating with 12 hrs of darkness. Both groups received food and water ad libitum. Liver glycogen content as well as phosphorylase activity showed, with slight differences, similar circadian variations. In a second experiment, mice under similar lighting conditions (LD 12:12), with water access ad libitum, were divided into two groups; one was offered food ad libitum while the other group recieved food from 0700 to 1800 only. This experiment allowed up to compare two different schedules of food intake; ad libitum, normal schedule (from 1800 to 0600) and reversed schedule (from 0700 to 1800). A complete reversal of the circadian rhythm was observed after 21 days in the group with the reverted feeding schedule. We conclude that food can function as the primary synchronizer in spite of the lighting regimen.     

Pattern of hyperphagia in immature three-spined sticklebacks after short-term food deprivation

Juvenile three-spined sticklebacks Gasterosteus aculeatus were fed live enchytraeid worms, and mean daily ad libitum consumption in the absence of periods of deprivation was 11·7% of initial body weight. Then, six groups of five replicate fish were subjected to 1, 3 and 6 days without food. Each period of deprivation was followed by 1 day of ad libitum feeding. The sequential order of deprivations differed between groups. Over the sequence of deprivations and re-feedings, mean cumulative consumption did not differ between groups. Mean daily consumption was 19·8% of initial body weight after a 1-day deprivation, 22·3% after 3 days and 19·5% after 6 days. However, consumption in the 24 h after a given length of deprivation also depended on the prior history of deprivation. Specific growth rate over the experiment did not differ between groups. The results provide evidence for an effective regulation of appetite in growing sticklebacks.     

Heat stress increases apical glucose transport in the chicken jejunum

In chickens, elevated environmental temperature reduces food intake. We have previously reported that, during heat stress, the intestinal mucosa has an increased capacity to take up sugars. To investigate whether the effects of warm environment on sugar uptake are an intestinal adaptation to lower energy intake or a response attributable to heat stress, we examined the glucose transport kinetics of apical and basolateral membranes of the jejunum and the mucosal morphology of broiler chickens maintained in climatic chambers for 2 wk. Experimental groups were 1) control ad libitum (CAL), fed ad libitum and in thermoneutral conditions (20 degrees C); 2) heat stress ad libitum (HSAL), fed ad libitum and kept in a heated environment (30 degrees C); and 3) control pair-fed (CPF), maintained in thermoneutral conditions and fed the same amount of food as that consumed by the HSAL group. Both the CPF and the HSAL groups showed reduced body weight gain, but only the HSAL chickens had lower plasma thyroid hormones and higher corticosterone than CAL and CPF groups. The fresh weight and length of the jejunum were only reduced in the HSAL group. The activity and expression of apical sodium-dependent glucose transporter 1 (SGLT-1) were increased by approximately 50% in the HSAL chickens, without effects in the CPF group. No changes in K(d) or in SGLT-1 and glucose transporter-2 K(m) were observed in the pair-fed and heated birds. These results support the view that increased intestinal hexose transport capacity is entirely dependent on adaptations of apical SGLT-1 expression to heat stress and is not due to reduced food intake.     

Heat increment of feeding and thermal substitution in mallard ducks feeding voluntarily on grain

The heat increment of feeding (HIF), including heat from digestion, assimilation, and nutrient interconversion, may substitute for thermogenesis and reduce thermoregulation costs. HIF and its substitution have been measured mainly in animals fed single large meals with high protein content, but many species such as some dabbling ducks (Anatini) feed more continuously in intermittent small meals with low protein content. We measured HIF in seven mallard ducks (Anas platyrhynchos) eating mixed grain (corn, wheat, milo) ad libitum while floating on water at 23 degrees C (thermoneutral) and 8 degrees C. HIF was calculated as the difference in oxygen consumption between fed and fasted birds, correcting for costs of behavior, heat storage (change in body temperature), and heating food. Substitution occurred if HIF was lower at 8 degrees C than at 23 degrees C. Food intake of mallards averaged 83% of that required for maintenance (zero energy balance) at 23 degrees C, and 68% of maintenance at 8 degrees C. Mean HIF (+/-1 SE) was 1.59+/-0.61 l O(2) at 23 degrees C and 1.48+/-0.68 l O(2) at 8 degrees C. These values were 4.9% and 3.9% of metabolizable energy intake, consistent with values expected for grain. HIF did not differ between temperatures (ANCOVA, birds as blocks, intake as covariate, P=0.51), indicating no measurable substitution at these intake levels in intermittent meals. For these large birds that feed on low-protein foods in intermittent small meals, the ecological importance of HIF substitution appears negligible during periods when food intake is below that required for energy balance.     

Effects of rearing temperature and level of food intake on organ size and tissue composition in piglets

Piglets are particularly susceptible to cold and nutritional stress because of their poor insulation and low body fat. The purpose of this study was to examine how ambient temperature and level of food intake affect development in piglets. Thirty-two piglets were reared individually from 14 to 56 days of age in either a cold (10 degrees C) or a warm (35 degrees C) environment. Two feeding regimens, restricted and ad libitum, were used to assess the effect of food intake on organ mass. The ad libitum fed pigs in both environments gained weight at the same rate. Paired t-tests of organ weights of ad libitum fed pigs revealed that the mass of the heart, liver, kidneys, stomach, and small intestine, and total nitrogen and the length of the small intestine were greater in cold-reared than in warm-reared littermates of the same body weight. The skin mass and total fat mass, the lengths of the body, extremities, and individual long bones, and the total surface area were greater in warm-reared than in cold-reared individuals. A regression analysis showed body weight was the most important determinant of size for all tissues measured except fat mass, which was affected slightly more by rearing temperature. Of the organs and tissue components that differed in size in warm- and cold-reared pigs, heart, kidney, stomach, skin, nitrogen, and fat mass, and small intestine length and surface area were generally affected more by rearing temperature than by level of food intake. Liver and small intestine mass and femur length were affected more by level of food intake.(ABSTRACT TRUNCATED AT 250 WORDS)     

Alternate day fasting impacts the brain insulin-signaling pathway of young adult male C57BL/6 mice

Dietary restriction (DR) has recognized health benefits that may extend to brain. We examined how DR affects bioenergetics-relevant enzymes and signaling pathways in the brains of C57BL/6 mice. Five-month-old male mice were placed in ad libitum or one of two repeated fasting and refeeding (RFR) groups, an alternate day (intermittent fed; IF) or alternate day plus antioxidants (blueberry, pomegranate, and green tea extracts) (IF + AO) fed group. During the 24-h fast blood glucose levels initially fell but stabilized within 6 h of starting the fast, thus avoiding frank hypoglycemia. DR in general appeared to enhance insulin sensitivity. After six weeks brain AKT and glycogen synthase kinase 3 beta phosphorylation were lower in the RFR mice, suggesting RFR reduced brain insulin-signaling pathway activity. Pathways that mediate mitochondrial biogenesis were not activated; AMP kinase phosphorylation, silent information regulator 2 phosphorylation, peroxisomal proliferator-activated receptor-gamma coactivator 1 alpha levels, and cytochrome oxidase subunit 4 levels did not change. ATP levels also did not decline, which suggests the RFR protocols did not directly impact brain bioenergetics. Antioxidant supplementation did not affect the brain parameters we evaluated. Our data indicate in young adult male C57BL/6 mice, RFR primarily affects brain energy metabolism by reducing brain insulin signaling, which potentially results indirectly as a consequence of reduced peripheral insulin production.     

Effects of caecectomy in the young adult female rat on digestibility of food offered ad libitum and in restricted amounts.

Caecectomized and sham-operated rats were fed a laboratory chow ad libitum and the effects of caecectomy on the digestibility of the food were studied. Compared with sham-operated controls, caecectomized rats showed a decrease in apparent digestibiltiy of organic matter from 77.8 to 73.0%, of crude protein from 83.0 to 79.4%, and of 'carbohydrate' from 74.6 to 69.0%. However, faecal water content increased from 41.6 to 54.8%. 51Cr-labelled EDTA was excreted faster in the faeces after caecectomy. The colon partly adapted to the loss of caecal mucosa by increased length and thus mucosal surface area. In a second concurrent experiment the effect of caecectomy on the apparent digestibility of food during food restriction was studied. Six caecectomized rats, comparable in all respects to those used in the first study, were fed the laboratory chow ad libitum for 3 weeks. They were then fed submaintenance amounts of food to achieve body weight losses of 40--50% and to maintain these low weights for 4 weeks. Finally, they were again fed ad libitum for 3 weeks. During the period of restriction the apparent digestibility of organic matter increased from 72.7 to 75.4%. This was largely due to the increased apparent digestibility of crude protein which rose from 78.4 to 81.9%. Digestibility coefficients returned to control values immediately upon refeeding ad libitum.     

Effects of photoperiod and food availability on growth, leptin, sexual maturation and maintenance in the Mongolian gerbils (Meriones unguiculatus)

Reproductive activity of Mongolian gerbils is regulated by photoperiod nevertheless body weight regulation is controlled without ambient photoperiod. Food intake is a major factor affecting rodent reproductive efficiency. Leptin is a hormone secreted by adipose tissue and modulates food intake, energy expenditure and body fat stores. In this study we studied the interaction of photoperiod and food availability on growth, sexual maturation and leptin concentration in the male and female gerbils. Gerbils were gestated and reared in either 14L:10D or 2L:22D. At weaning, gerbils were housed individually and divided into three groups: fed ad libitum, fed 80% of ad libitum or fed 60% of ad libitum. Body weights were recorded at weaning and every week thereafter. After twelve weeks of treatment, animals were sacrificed and testes and uterine weights were determined and blood was collected for leptin measurement. Food restriction reduced body weight and inhibited reproductive development. Absolute paired testis weights were similar in ad lib and 80% of ad lib groups but significantly different compared with the 60% of ad lib group in both photoperiods. Body weights were also directly dependent upon the level of food restriction. Uterine mass was only affected in the 60% of ad lib group in 14L but both food restriction levels significantly affected the uterine weights in 2L. Significant variations were found in leptin profiles. Leptin concentration was highest in ad lib and 80% of ad lib groups and lowest in 60% of ad lib groups. These results suggest that the reproductive activity of Mongolian gerbils is sensitive to food intake and multiple potential environmental cues (e.g., food availability, temperature) can be utilized.     

Hepatic insulin binding following in utero exposure to ethanol

Insulin binding to liver membranes has been studied in term fetuses of rats fed ethanol-containing liquid diet during pregnancy . Pair-fed and ad libitum-fed controls received liquid diet in which maltose-dextrins were substituted isocalorically for ethanol. Food consumption and body weigh gain of ethanol- imbibing dams were 35% and 70% less than their ad libitum counterparts respectively. Ethanol-fed rats also exhibited less gain in body weight than pair-fed controls despite isocalorically equivalent food intake. The number of live pups was not different among the various groups; however, liver weight of fetuses exposed to ethanol in utero was 47% less than those of the pups of ad libitum control dams and 28% less than those of the offspring of pair-fed control rats. Insulin binding to liver membranes of fetuses exposed to ethanol in utero was lower than that of ad libitum controls but was not significantly different from that of the pair-fed control animals. Average affinity profiles showed a reduction in K at all levels of receptor occupancy in the fetuses of ethanol-fed rats. For fetuses of the pair-fed group, K was reduced only at fractional occupancy below 20% but not at higher fractional occupancy. Because of the similarity of insulin binding in the fetuses of the ethanol-fed rats and their pair-fed counterparts, effects of ethanol on insulin binding cannot account for the reduced hepatic glycogen stores previously reported in term fetuses.     

The effect of feeding frequency on consumption of food,absorption efficiency,and gonad production in the sea urchin Lytechinus variegatus

The frequency of feeding in the field is variable in sea urchins, ranging from nearly continuous to diel or intermittent. It is essential to know the effect of feeding interval on physiological and metabolic processes to understand the basis for production. Lytechinus variegatus (50 mm horizontal diameter) were collected in January 1999 and held in closed-circuit aquaria at 25 degrees C and 35 per thousand salinity. After 9 days without food, individuals were fed one of three treatments: food available ad libitum, food available for 1 day every 2 days or food available for 1 day every 4 days for 28 days. The rate of food consumption per day of all individuals was high the first week of feeding. It then decreased to a lower, constant rate in those fed ad libitum but remained high in those fed one day every 2 or 4 days. The total amount eaten was directly related to frequency of feeding. The apparent dry matter digestibility (absorption efficiency) did not vary with frequency of feeding. As the total amount of energy absorbed was directly related to the frequency of feeding, the increase in the rate of food consumption does not compensate for a decrease in frequency of feeding. Gonad production efficiency was directly related to frequency of feeding. Gonad gross production (assimilation) efficiencies were 8.4, 3.9 and 3.4% for individuals fed every day, or fed one day every 2 and 4 days, respectively. The corresponding gonad net assimilation efficiencies were 12.5, 5.5, and 4.8%. A decrease in frequency of food availability results in use of a greater proportion of the food consumed for maintenance and less for gonad production.     

Activation of glycogen synthase in myocardium induced by intermittent hypoxia is much lower in fasted than in fed rats

Obstructive sleep apnea is characterized by intermittent obstruction of the upper airway, which leads to intermittent hypoxia. Myocardial glycogen is a major energy resource for heart during hypoxia. Previous studies have demonstrated that intermittent hypoxia rapidly degrades myocardial glycogen and activates glycogen synthase (GS). However, the underlying mechanisms remain undefined. Because sleep apnea/intermittent hypoxia usually happens at night, whether intermittent hypoxia leads to GS activation in the postabsorptive state is not known. In the present study, male adult rats were studied after either an overnight fast or ad libitum feeding with or without intermittent ventilatory arrest (3 90-s periods at 10-min intervals). Hearts were quickly excised and freeze-clamped. Intermittent hypoxia induced a significant decrease in myocardial glycogen content in fed rats and stimulated GS in both fasted and fed rats. However, the portion of GS in the active form increased by approximately 38% in fasted rats compared with a larger, approximately 130% increase in fed rats. The basal G-6-P content was comparable in fasted and fed animals and increased approximately threefold after hypoxia. The basal phosphorylation states of Akt and GSK-3beta and the activity of protein phosphatase 1 (PP1) were comparable between fasted and fed control rats. Hypoxia significantly increased Akt phosphorylation and PP1 activity only in fed rats. In contrast, hypoxia did not induce significant change in GSK-3beta phosphorylation in either fasted or fed rats. We conclude that hypoxia activates GS in fed rat myocardium through a combination of rapid glycogenolysis, elevated local G-6-P content, and increased PP1 activity, and fasting attenuates this action independent of local G-6-P content.     

Effects of long-term dietary restriction on body temperature are modified with increasing age

Effects of long-term dietary restriction on body temperature and its circadian changes were investigated in 3.5- and 14.5-month-old male Long-Evans rats. Animals were either fed and libitum or kept on a restricted diet for 8 weeks. Purina Lab Chow was constantly available to the ad libitum-fed groups, while half portions of their daily food consumption were given to age-matched diet-restricted groups every day. A highly significant lowering of body temperature in middle-aged diet-restricted (MR) rats was not observed until their food intake had been restricted for 5 weeks compared with that of the middle-aged ad libitum-fed (MA) group as well as that of the young diet-restricted (YR) rats. Eight weeks after diet restriction, both the circadian pattern of body temperature and its diurnal peak-trough difference remained almost unchanged in all four groups, while the average body temperature of MR rats was greatly lower than that of the YR group and that of MA animals. No significant difference in average body temperature was found between the young ad libitum-fed (YA) rats and the MA group. These data suggest that the average body temperature and its circadian changes in ad libitum-fed rats, at least before the age of 14.5 months, is not age-related, while the effect of dietary restriction on body temperature may be modified with increasing age.     

Effect of cycles of feed deprivation on growth and food consumption of immature three-spined sticklebacks and European minnows

Individual juvenile three-spined sticklebacks Gasterosteus aculeatus and European minnow Phoxinus phoxinus , from sympatric populations, were subjected to four cycles of 1 week of food deprivation and 2 weeks of ad libitum feeding. Mean specific growth rate during the weeks of deprivation was negative and did not differ between species. The three-spined stickleback showed sufficient growth compensation to recover to the growth trajectory shown by control fish daily fed ad libitum . The compensation was generated by hyperphagia during the re-feeding periods, and in the last two periods of re-feeding, the gross growth efficiencies of deprived three-spined sticklebacks were greater than in control fish. The expression of the compensatory changes in growth and food consumption became clearer over the successive periods of re-feeding. The European minnow developed only a weak compensatory growth response and the mass trajectory of the deprived fish deviated more and more from the control trajectory. During re-feeding periods, there were no significant differences in food consumption or gross growth efficiency between control and deprived European minnows. The differences between the two species are discussed in terms of the possible costs of compensatory growth, the control of growth and differences in feeding biology.