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Lipid Reserves (lipid + reserve)

Distribution by Scientific Domains

Life Sciences	58%
Earth and Environmental Science	41%

Selected Abstracts

Comparative energy allocation in two sympatric, closely related gobies: the black goby Gobius niger and the grass goby Zosterisessor ophiocephalus

JOURNAL OF FISH BIOLOGY, Issue 2 2007
R. Fiorin
Seasonal energy allocation of lipid reserves into different body tissues was analysed comparatively in two sympatric, closely related gobies: the grass goby Zosterisessor ophiocephalus and the black goby Gobius niger. Lipid reserves were measured in liver, muscle and ovary and compared between the two species within a given sex and seasonal period (reproductive v. non-reproductive). Furthermore, temporal patterns of lipid reserves were investigated in the two species in relation to gonado-somatic and liver-somatic indices, as well as the relationship between size and lipid content. Results showed that the grass goby allocated more lipid reserves in reproduction while the black goby accumulated more reserves in liver and muscle, at a given size, although the temporal patterns of lipid accumulation and depletion were basically similar. Results are discussed in the light of life-history theories, taking into account both adaptation and evolutionary constraints. [source]

Effects of sugar feeding on carbohydrate and lipid metabolism in a parasitoid wasp

PHYSIOLOGICAL ENTOMOLOGY, Issue 1 2000
D.A.W.N. M. Olson
Summary Lifetime patterns of carbohydrate and lipid metabolism were compared in starved and sucrose-fed adults of the parasitoid Macrocentrus grandii (Goidanich) (Hymenoptera: Braconidae). As expected, sucrose-fed individuals lived longer than did starved individuals. Macrocentrus grandii males and females eclosed with levels of simple storage sugars (presumably primarily trehalose) and glycogen that were below maximum levels recorded from sucrose-fed parasitoids. Both of these nutrients dropped to very low levels in starved individuals within 4 days post-emergence and were maintained at high levels in sucrose-fed individuals throughout their lives. Lipid reserves at emergence represented the highest lipid levels for both sexes in the two diet treatments, with levels declining over the lifetimes of males and females from both diet treatments. Our results therefore suggest that dietary sucrose is used to synthesize trehalose and glycogen, but not lipids in M. grandii. Also, in contrast to the patterns observed for the simple sugars and glycogen, lipid levels in starved individuals did not drop below levels observed in sugar-fed individuals. The average number of mature eggs carried by females at emergence was 33 and increased to approximately 85 in sucrose-fed and 130 in starved females by the age of 5 d in the absence of hosts. The egg maturation rate was therefore higher in starved than in sugar-fed females. Potential explanations for this unexpected result are discussed. [source]

Effects of feeding levels on growth performance, feed utilization, body composition and apparent digestibility coefficients of nutrients for juvenile Chinese sucker, Myxocyprinus asiaticus

AQUACULTURE RESEARCH, Issue 7 2010
Yong-Chao Yuan
Abstract An experiment was conducted to determine effects of feeding levels on growth performance, feed utilization, nutrient deposition, body composition and apparent digestibility coefficients (ADCs) of nutrients for juvenile Chinese sucker (initial weight, 11.77±0.22 g). Chinese sucker were fed a practical diet from 0% (starvation) to 4.0% (at 0.5% increments) body weight (bw) day,1 for 8 weeks. The results showed that growth performance, feed utilization, nutrient deposition, body composition and ADCs of dry matter, protein and energy were significantly (P<0.05) affected by feeding levels. Survival was the lowest for the starvation group. Final mean body weight, growth rate, thermal-unit growth coefficient (TGC) increased with feeding rate from 0% to 3.0% bw day,1 (P<0.05) and showed no significant differences above the level (P>0.05). Feed conversion rate was significantly lower at a feeding level of 2.5% bw day,1 than above and below the level (P<0.05). Protein efficiency ratio was markedly highest at the 2.5% bw day,1 ration level (P<0.05). Fish fed at the feeding level (1.0% bw day,1), which represented a maintenance ration (energy gain was less than 2.27 kJ fish,1 day,1), showed positive protein deposition but negative lipid deposition. This indicates that fish fed a maintenance ration mobilize body lipid reserve to support protein deposition. Lipid contents of whole body, muscle and liver increased with increasing feeding rates from 0.5% to 3.0% bw day,1 and showed no significant differences above the level (P>0.05). Protein contents of whole-body composition increased with feeding rate from 0.5 to 3.0% bw day,1 (P<0.05) and showed no significant differences above the level (P>0.05), whereas muscle and liver remained relatively stable with the different ration amount with the exception of fish fed a ration of 0.5% bw day,1, at which Chinese sucker possessed significantly lower body protein concentration (P<0.05). The ADCs of dry matter, protein and energy decreased with increasing feeding levels from 0.5% to 3.0% bw day,1 and then remained relatively constant over the level. Based on the broken-line regression analysis using WG data, the optimum and maintenance feeding levels for Chinese sucker were 3.10% bw day,1 and 0.45% bw day,1 respectively. [source]

Interaction of an insecticide with larval density in pond-breeding salamanders (Ambystoma)

FRESHWATER BIOLOGY, Issue 4 2005
BRIAN S. METTS
Summary 1. Amphibian populations residing in or near agricultural areas are often susceptible to pesticide contamination. Recent evidence suggests that the effects of pesticides on amphibians often exceed those estimated in laboratory toxicity tests because other environmental factors (e.g. predators, resource abundance) can influence pesticide toxicity. 2. To examine the effects of an insecticide (carbaryl) on two species of Ambystoma salamanders experiencing the natural stress of competition, we manipulated chemical concentration (control, 3.5 and 7.0 mg L,1) and larval density (low and high). We determined the effect of treatments on snout-vent length (SVL), growth rate, lipid reserves, time to metamorphosis, per cent survival and per cent metamorphosis. 3. Carbaryl negatively affected all response variables of Ambystoma maculatum significantly, and significantly reduced survival and metamorphosis of A. opacum. Increased density significantly influenced SVL, lipid reserves, growth rate and metamorphosis of A. maculatum. 4. The effects of carbaryl and increased density on per cent metamorphosis were nearly additive, but were generally less than additive on other variables. 5. The negative effects of chemical contamination on salamanders were likely because of pesticide-induced reductions of food resources, as zooplankton abundance decreased by as much as 97% following carbaryl application. 6. Our study demonstrates the importance of the interactive effects that chemical contamination and natural environmental factors have on salamanders. [source]

Energetics approach to predicting mortality risk from environmental stress: a case study of coral bleaching

FUNCTIONAL ECOLOGY, Issue 3 2009
Kenneth R. N. Anthony
Summary 1Coral bleaching events, predicted to increase in frequency and severity as a result of climate change, are a threat to tropical coral-reef ecosystems worldwide. Although the onset of spatially extensive, or ,mass', bleaching events can be predicted using simple temperature stress metrics, no models are available for predicting coral mortality risk or sub-lethal stress associated with bleaching. Here, we develop a model that links the functional response of colony energy balance and energy-store dynamics to coral mortality risk and recovery during and following bleaching events. 2In a series of simulations using response functions and parameter values derived from experimental studies for two Indo-Pacific coral species (Acropora intermedia and Montipora monasteriata), we demonstrate that prior energy-costly disturbances and alternative energy sources are both important determinants of coral mortality risk during and following bleaching. 3The timing of the onset of coral mass mortality is determined by a combination of bleaching severity (loss rate of photopigments), duration of the bleaching event, heterotrophy and the size of energy reserves (as lipid stores) before bleaching occurs. 4Depending on initial energy reserves, model results showed that high rates of heterotrophy could delay the onset of coral mortality by up to three weeks. Survival following bleaching was also strongly influenced by remaining lipid reserves, rates of heterotrophy, and rates of photopigment (or symbiont) recovery. 5Our results indicate that energy-costly disturbances and low availability of food, before and during bleaching events, respectively, work to increase bleaching-induced coral mortality risk for acroporid corals on Indo-Pacific reefs. [source]

Airspeed adjustment and lipid reserves in migratory Neotropical butterflies

FUNCTIONAL ECOLOGY, Issue 2 2008
R. Dudley
Summary 1Aerodynamic theory predicts that migrant fliers should reduce their speed of flight as endogenous energy reserves are gradually consumed. This prediction was tested for butterfly species (Pieridae and Nymphalidae) that engage in annual rainy season migrations through central Panama. 2Direct airspeed measurements were made on butterflies in natural free flight, followed by chloroform : methanol extractions of abdominal lipids from the same insects. 3Among individuals within particular species/gender subsets, airspeeds during flight were higher with greater lipid content following adjustment for body mass. Although it was not possible to measure lipid content repeatedly on a single insect, these comparisons among individuals for five migratory species suggest that butterflies reduce their flight speed as lipid reserves are progressively depleted. 4Because choice of airspeed can strongly influence the rate of energetic expenditure, these results together with previously described strategies of wind drift compensation in the same taxa demonstrate sophisticated long-distance orientation and optimization strategies by migratory Neotropical butterflies flying within the boundary layer. [source]

Subcellular distribution of key enzymes of lipid metabolism during the euthermia-hibernation-arousal cycle

JOURNAL OF ANATOMY, Issue 6 2009
Anna Suozzi
Abstract Mammalian hibernation is a natural, fully reversible hypometabolic state characterized by a drastic reduction of body temperature and metabolic activity, which ensures survival to many species under adverse environmental conditions. During hibernation, many hibernators rely for energy supply almost exclusively on lipid reserves; the shift from carbohydrate to lipid metabolism implies profound rearrangement of the anabolic and catabolic pathways of energetic substrates. However, the structural counterpart of such adaptation is not known. In this study we investigated, by using immunoelectron microscopy, the fine intracellular distribution of two key enzymes involved in lipid metabolism, namely, the fatty acid synthase (FAS) and the long-chain fatty acyl-CoA synthetase (ACSL), in hepatocytes of euthermic, hibernating and arousing hazel dormice. Our results show that the two enzymes are differentially distributed in cellular compartments (cytoplasm, mitochondria and cell nuclei) of hepatocytes during euthermia. Quantitative redistribution of both enzymes among cellular compartments takes place during hibernation and arousal, in accordance with the physiological changes. Interestingly, this redistribution follows different seasonal patterns in cytoplasm, mitochondria and nuclei. In conclusion, our data represent the first quantitative morphological evidence of lipid enzyme distribution in a true hibernator throughout the year cycle, thus providing a structural framework to biochemical changes associated with the hypometabolism of hibernation. [source]

Characterizing the nutritional strategy of incubating king eiders Somateria spectabilis in northern Alaska

JOURNAL OF AVIAN BIOLOGY, Issue 6 2008
Rebecca L. Bentzen
We measured plasma concentrations of variables associated with lipid metabolism (free fatty acids, glycerol, triglyceride, and ,-hydroxybutyrate), protein metabolism (uric acid), and baseline corticosterone to characterize the nutritional state of incubating king eiders Somateria spectabilis and relate this to incubation constancy at two sites, Kuparuk and Teshekpuk, in northern Alaska. King eiders at both sites appeared to employ a partial-income incubation strategy, relying on both endogenous and exogenous energy resources. Females maintained high invariant levels of free fatty acids, ,-hydroxybutyrate, and glycerol throughout incubation, indicating that fat reserves were a major energy source, and not completely depleted during incubation. Similarly, uric acid did not increase, suggesting effective protein sparing or protein ingestion and adequate lipid reserves throughout incubation. Baseline corticosterone and triglyceride levels increased during incubation, indicative of an increase in foraging during late stages of incubation. Incubating females at Kuparuk had higher triglyceride concentrations but also had higher ,-hydroxybutyrate concentrations than females at Teshekpuk. This dichotomy may reflect a short-term signal of feeding overlaying the longer-term signal of reliance on endogenous lipid reserves due to higher food intake yet higher metabolic costs at Kuparuk because of its colder environment. Incubation constancy was not correlated with plasma concentrations of lipid or protein metabolites. [source]

Comparative energy allocation in two sympatric, closely related gobies: the black goby Gobius niger and the grass goby Zosterisessor ophiocephalus

Biochemical composition of the Atlantic bonito Sarda sarda from the Aegean Sea (eastern Mediterranean Sea) in different stages of sexual maturity

JOURNAL OF FISH BIOLOGY, Issue 2 2006
N. Zaboukas
The content (% wet mass) in water, ash, lipid, crude protein, DNA and RNA of different tissues was determined during sexual maturation of bonitos Sarda sarda from the Aegean Sea. A total of 220 specimens were collected in the following stages of sexual maturity: immature, resting, developing, mature, spawning and spent. Highest lipid levels in the white muscle, red muscle and liver were measured in immature specimens, while lowest levels were found in spawning bonitos. The gradual percentage of lipid reduction from immature to spawning bonitos was relatively higher in the liver (females 71·2% and males 64·4%) than in the white (females 59·2% and males 53·5%) and red (females 62·1% and males 51·7%) muscle. Lipid levels in the gonads increased gradually from the immature to spawning stage. The decrease of lipid in the somatic tissues was more intense in females than in males, and gonadal lipid content was higher in females than in males. There was a strong reverse correlation between water and lipid percentage in all tissues. Protein content decreased significantly only in spawning bonitos. The percentage of protein reduction from immature to spawning stage was relatively higher in males than in females in both white (females 3·4% and males 4·6%) and red (females 4·6% and males 5·1%) muscles. Protein content in the liver was significantly lower than in the other tissues, being highest in mature females. Gonadal protein content in females increased with maturation and decreased after spawning. The content in ash exhibited considerable stability. The RNA:DNA ratio exhibited a similar pattern of variation in both muscles. The RNA:DNA ratio increased during gonadal development gradually from the developing to spent stage. It was concluded that in S. sarda during gonadal development, there was an increase in gonadal lipid accompanied by a decrease in somatic tissue lipid reserves. Thus, reproductive inactive bonitos have more lipid in their edible part and a higher nutritional value than active ones. [source]

Nutritional condition of Anguilla anguilla starved at various salinities during the elver phase

JOURNAL OF FISH BIOLOGY, Issue 2 2005
A. Rodríguez
The effects of food deprivation and environmental salinity (<1, 10 and 20) on survival, fish morphology, organization of the digestive system and body lipid reserves in European eel Anguilla anguilla during the transition from glass eel to elver, were evaluated. Fasted elvers kept in fresh water were able to withstand starvation for >60 days, while those in brackish environments (salinity 10 and 20) reached the level of irreversible starvation at 37 and 35 days, respectively. The high level of lipid reserves contained in liver inclusions and the abdominal cavity (perivisceral deposits) in elvers might explain their long resistance to starvation and differences in fasting tolerance under different salinities. Fasting resulted in a significant reduction of the elvers' condition factor and body depth. There were severe histopathological changes in the digestive system and musculature, such as the alteration of the liver organization, and hepatic glycogen and lipid content, shrinkage of enterocytes and reduction of their height, pancreas degeneration, autolysis of the oesophageal and intestinal mucosa and disarrangement of myofibrils and degeneration of trunk musculature. Degeneration of the oesophageal and intestinal mucosa as a consequence of fasting might have impaired digestive and osmoregulatory functions in feed-deprived fish, directly affecting the tolerance to starvation and survival. Length of food deprivation was associated with a significant increase in mortality, coefficient of variation, cannibalism and point of no return at high salinities. Mortality was dependent on food deprivation and salinity concentrations. Environmental salinity directly influenced the ability of elvers to withstand starvation; once glass eels metamorphosed into elvers, they tolerated starvation better in fresh water than in brackish environments. [source]

Lipid dynamics in the viperine snake, Natrix maura, from the Ebro Delta (NE Spain)

OIKOS, Issue 1 2004
Xavier Santos
Body reserves play a major role in several aspects of vertebrate biology. Accurate identification and quantification of body reserves constitute a useful contribution to the better understanding of the energetic costs of reproduction and the implication of food availability in life history traits of organisms. In this study, lipid content in fat bodies, liver and muscle of the viperine snake (Natrix maura) were measured along an active season. Samples were collected monthly from a natural population of the Ebro Delta Natural Park (NE Spain). This methodology pointed out that lipids stored in fat bodies were the main energetic source during reproduction. In addition, lipids stored in liver appeared to be critical for vitellogenesis, while lipids stored in muscle turned out to be a supplementary energetic resource to fuel reproductive effort. Relationships between changes in body reserves and prey availability in canals of the Ebro Delta were also considered. In males, lipid reserves presented a positive correlation with food availability. On the contrary, lipid reserves in female viperine snakes decreased during vitellogenesis even though food availability increased in this period, which suggests a quick transfer of body lipids to clutch. In April, when rice fields of the Ebro Delta were dry and aquatic prey was scarce for viperine snakes, males and females presented a lower lipid content in fat bodies, liver and muscle than they did in other months, showing a clear link between prey availability and body reserves during food shortage. Thus, patterns of variation in fat levels indicated that Natrix maura is a capital breeder since it acquires resources in advance and stores them until they are invested during the reproductive period. Nevertheless, the shortage in April forces Natrix maura to turn into a facultative income breeder to fuel vitellogenesis. Finally, fat reserves in body components were compared with an estimate of body condition calculated by the residuals from the regression of body mass on body length. In male viperine snakes, the estimate of body condition was correlated with fat levels, revealing that this index is useful to measure condition in living individuals. On the contrary, body condition in females was not correlated with fat levels, which suggests that it is not appropriate to infer condition in female viperine snakes since it depends on the reproductive status of the individuals. [source]

Lifespan and patterns of accumulation and mobilization of nutrients in the sugar-fed phorid fly, Pseudacteon tricuspis

PHYSIOLOGICAL ENTOMOLOGY, Issue 3 2005
Henry Y. Fadamiro
Abstract., The effect of sugar feeding on the survival of adult phorid fly Pseudacteon tricuspis is investigated. Flies fed 25% sucrose in aqueous solution continuously throughout their lifespan have greater longevity (mean ± SE longevity: female = 7.9 ± 0.8 days, male = 8.9 ± 0.9 days) than completely starved (provided no water and no sugar solution) flies, sugar-starved (provided water only) flies, or flies fed sugar solution only on their first day of adult life. Completely starved flies rarely lived beyond one day. Provision of water increases longevity by 2 days, and one full day of sugar feeding further increases longevity by an additional 1,2 days. Flies fed 50% sucrose have similar survivorship as those fed 25% sucrose. The temporal patterns of nutrient accumulation and utilization are also compared in P. tricuspis fed different diets: sugar-starved, sucrose-fed on the first day of adult life only, and sucrose-fed continuously. Adult P. tricuspis emerge with no gut sugars, and only minimal amounts of body sugars and glycogen. Although the levels of body sugars and glycogen decline gradually in sugar-starved flies, a single day of sugar feeding results in the accumulation of maximum amounts of gut sugars, body sugars and glycogen. High levels of these nutrients are maintained in female and male phorid flies fed on sucrose continuously over the observation period, whereas nutrient levels decline in flies fed only on the first day of life, beginning 1 day postfeeding. Female and male P. tricuspis emerge with an estimated 12.3 ± 2.3 and 7.2 ± 1 g of lipid reserves per fly, respectively. These teneral amounts represent the highest lipid levels detected in adult flies, irrespective of their diet, and are maintained over the life times of sucrose-fed female and male flies, but declined steadily in sugar-starved females. These data suggest that adult P. tricuspis are capable of converting dietary sucrose to body sugars and glycogen, but not lipids. [source]

Heritability and physiological correlates of migratory tendency in the grasshopper Melanoplus sanguinipes

PHYSIOLOGICAL ENTOMOLOGY, Issue 4 2001
Jack W. Kent JR
Abstract. Durations of tethered flights by the North American migratory grasshopper Melanoplus sanguinipes Fabricius are bimodally distributed: most individuals either will not fly, or else will fly for many hours. This observation suggests a simple measure (the ,one-hour rule') for distinguishing migrants from non-migrants. This measure is repeatable (repeatability = 0.6,0.7). Using laboratory-reared offspring of grasshoppers from an Arizona population of mixed migratory tendency, a breeding experiment was conducted to determine the heritability of migratory tendency and possible correlated responses to selection on migratory behaviour. When migratory tendency is considered as a threshold trait, the heritability of liability is in the range 0.5,0.6. Most families in the breeding experiment had at least some migrants among their offspring; selection on migratory incidence had a correlated effect on the durations of flights by these individuals. The magnitude of thoracic lipid reserves showed a modest correlated response to selection on migratory behaviour. Thoracic and abdominal lipid reserves in identified migrants are reduced by flight, indicating that lipid is mobilized and consumed during flight in this species. [source]

Interactive effects of temperature and diet on the growth and biochemical composition of juveniles of the pearl oyster Pinctada mazatlanica

AQUACULTURE RESEARCH, Issue 11 2009
Pedro E Saucedo
Abstract The combined effects of temperature and diet on the growth and biochemical composition of juveniles of the pearl oyster Pinctada mazatlanica at the hatchery were investigated. Specimens were subjected to a combination of four temperatures (20, 23, 26 and 29 °C) and five microalgal diets (Isochrysis galbana alone, I. galbana+Pavlova salina, I. galbana+Chaetoceros muelleri, C. muelleri+P. salina and I. galbana+P. salina+C. muelleri). An increase in shell height occurred in a linear pattern, while wet weight gain fitted a power law. Temperature, more than diet, exerted a stronger influence on the growth and condition of the specimens. The combination of 29 °C with P. salina+C. muelleri led to the fastest growth in shell height, while the combination of 29 °C with I. galbana+C. muelleri led to the highest wet and dry weight biomass. In contrast, specimens grew significantly less in shell height and wet weight at 20 °C, regardless of the diet. At all temperatures, the monoalgal diet of I. galbana led to the slowest growth of specimens, but in turn favoured the highest levels of protein, carbohydrate and lipid reserves as a possible strategy to store more energy reserves under stressful events. [source]