Pathways and places associated with nonindigenous aquatic species introductions in the Laurentian Great Lakes

The present study aimed to evaluate the health status of Octopus maya females on different days after spawning (days 0, 10, 20, 30, and 40). A total of 25 O. maya females were examined in terms of physiological (i.e., weight loss, hepatosomatic and gonadosomatic indexes, and hemocyanin, protein, glucose, cholesterol, and acylglycerides concentrations in plasma) and immunological variables (i.e., total hemocyte count, hemagglutination, and phenoloxidase activity). We hypothesized that O. maya females should maintain their physiological integrity throughout the post-spawning period until the hatching of the offspring. Results showed that the physiological and immunological indicators measured in post-spawning females significantly changed with time. Loss of body weight over time and a decrease in the hepatosomatic and gonadosomatic indexes were observed. Hemolymph components showed variations that reflect the consumption of reserves and coincide with an increased immune process of hemagglutination and phenoloxidase activity in hemocytes. Our results demonstrate that O. maya females are adapted to maintain an adequate state of health to care for their spawn despite the long period of starvation and contribute to the identification of the mechanisms involved in maintaining the integrity of these animals during one of the most critical phases of their life cycle.     

Fasting and refeeding in carp,Cyprinus carpio L.: the mobilization of reserves and plasma metabolite and hormone variations

Summary Carp, Cyprinus carpio, were subjected to a short term of fasting (2 months) and 12 days of refeeding. The early changes produced in plasma metabolites and hormones (insulin and glucagon) and their respective energy contribution in liver and muscle during fasting and refeeding was studied. Two phases of fasting were differentiated. The first phase (until day 8 of fasting) was characterized by a reduction in the hepatosomatic index mainly due to glycogen mobilization. A transitory increase in plasma glucose and lactate suggested an initial increase in energy demand. No changes were produced in the percentage of glycogen and protein in muscle, but musculosomatic index and the total body muscle protein decreased. Although the most depleted tissue in this phase was the liver, the loss of energy content of total muscle was higher. Stabilization of liver glycogen content, plasma glucose and lactate levels, decreased muscle protein levels and a reduction in the rate of body weight loss characterized the second phase (from day 8 of fasting). Protein content in whole muscle decreased by 22%, similar to the first phase. The energy expenditure of both liver and muscle was lower in this phase. Plasma insulin levels decreased two-fold and plasma glucagon three-fold in the first phase and remained low in the second phase of fasting. Twelve days of refeeding produced a greater increase in daily growth rate than in the control group and a recovery of plasma insulin, glucagon and glucose levels. Liver completely recovered. In contrast, musculosomatic index, protein and lipid content indicated that muscle did not completely recover from the 2 months of fasting, although and overshoot of muscle glycogen was observed.Abbreviations ANOVA analysis of variance - bw body weight - D1, D2, D5, D8, D19, D50 1, 2, 5, 8, 19 and 50 days of fasting, respectively - GSI gonadosomatic index - HSI hepatosomatic index - MSI musculosomatic index - P-DNA deoxyribonucleic acid phosphorus     

Physiological and metabolic adjustments of Hoplosternum littorale (Teleostei,Callichthyidae) during starvation

All animals face the possibility of limitations in food resources that could ultimately lead to mortality caused by starvation. The primary goal of this study was to characterize the various physiological strategies that allow fish to survive starvation. A multiparametric approach, including morphological biomarkers, blood plasma metabolites, oxidative stress and energy reserves, was used to assess starvation effects on the fish Hoplosternum littorale. Adult specimens were maintained at four experimental groups: control (fed ad libitum), and starved (not fed) fish for 7 and 28 days. Significant changes were observed not only after 28 days, but also after 7 days of starvation. In the shorter period, the hepatosomatic index as well as plasma triglycerides and glucose were significantly lower in starved fish than in the control ones. These results were accompanied by reduced lipid, glycogen and protein reserves in liver and diminished glycogen content in muscle, suggesting the need of these macromolecules as fuel sources. In addition, increased antioxidant enzyme activities were observed in gills, without evidence of oxidative stress in any of the evaluated tissues. Most significant differences were found in 28-days starved fish: total body weight together with the hepatosomatic index was lower when compared to control fish. The plasmatic metabolites tested (glucose, triglyceride, cholesterol and protein), all energy reserves in liver and glycogen content in muscle decreased in 28-days starved fish. Lipid oxidative damage was reported in liver, kidney and brain, and antioxidant enzymes (GST, GR, GPx and CAT) were activated in gills. According to the multivariate analysis, oxidative stress markers and metabolic parameters were key biomarkers that contributed in separating starved from fed fish. Our study allowed an integrated assessment of the fish response to this particular condition.     

Concentrations of carbohydrates and lipids of guinea pigs after five days starvation

The concentrations of serum total lipids, cholesterol and triglycerides of guinea pigs were determined under normal conditions and after 5 days fasting. Serum glucose and liver glycogen levels were also estimated under both conditions. The amounts of serum total lipids and cholesterol were significantly increased as a result of starvation, whereas, fasting had no significant effect on serum triglycerides. Liver glycogen was rapidly decreased in response to starvation in a highly significant manner. However, starvation did not affect serum glucose of guinea pigs.     

Comparative study of the metabolic responses during food shortage and subsequent recovery at different temperatures in the adult lesser mealworm, Alphitobius diaperinus (Coleoptera: Tenebrionidae)

Metabolic responses to prolonged food shortage (35 days) and subsequent re‐feeding (14 days) were investigated in adults of an introduced beetle, Alphitobius diaperinus Panzer, as a function of temperature (12, 16, 20 and 24 °C). Various qualitative and quantitative changes that greatly vary according to the temperature experienced occurred in metabolite levels during prolonged starvation. Whereas levels of protein and ATP did not change significantly, triglycerides decreased markedly and glycogen changed little. Metabolite levels were differently affected by temperature, with triglycerides being less rapidly degraded at 20 than at 24 °C and almost completely depleted at 12 and 16 °C; in contrast to higher temperatures, glycerol is accumulated at 12 °C. Physiological adaptation to starvation and low temperatures are highly linked and energy allocation for starvation vs. temperature acclimation must be strictly regulated, both being essential for insect survival. Re‐synthesis rates during recovery are probably highly temperature‐dependent for all metabolites. The proteins retained during starvation and the preferential degradation of lipids allowed a rapid recovery. Above 16 °C, adult A. diaperinus regained locomotory activity rapidly and the triglyceride, glycerol and glycogen reserves were restored. This tropical species may be able to colonize other environments such as natural and/or artificial biotopes where conditions are close to those of its natural habitat.     

Metabolic responses to prolonged starvation, food restriction, and refeeding in the brown trout, Salmo trutta: oxidative stress and antioxidant defenses

The effects of long-term starvation and food restriction (49 days), followed by refeeding (21 days) have been studied with respect to antioxidant defense in the liver and gills (branchial tissues) of the brown trout, Salmo trutta. Malondialdehyde levels in both tissues increased in parallel with starvation and food restriction and these values did not return to normal after the refeeding period. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) in liver and gills increased during the 49 days of starvation, but glucose-6-phosphate dehydrogenase (G6PD) activities decreased. Glutathione S-transferase (GST) activity decreased in the liver at the 49th day of starvation, but increased in the branchial tissues. Some of the antioxidant enzyme activities (such as hepatic GST and branchial G6PD) returned to control values of fed fish after the refeeding period, but others (e.g. hepatic SOD and branchial GPx) did not return to normal values. In conclusion, our study indicates that total or partial food deprivation induces oxidative stress in brown trout.     

The effects of starvation and refeeding on plasma amino acid levels in carp, Cyprinus carpio L., 1758

Plasma amino acid (AA) levels of carp, Cyprinus carpio L., 1758, were analysed after various periods of starvation as well as after 12 days of refeeding. The levels were compared to control groups, which had been previously fasted for 24 h. A positive correlation between dietary and plasma essential amino acid (EAA) concentrations was observed in all of the control groups.
The effect of starvation on the dynamics of AA concentration was different according to the period of starvation. Fasting already produced a decrease of total α-AA levels at 2 days, and these low levels were maintained until 5 and 8 days. These short periods of fasting affected the levels of EAA (especially branched-chain AA) more than those of non-essential amino acids (NEAA). The only AA that increased was Ala, which rose at 5 days of starvation, surpassing the levels of the control group. These high levels were maintained until 19 days of starvation.
A different situation was observed at 19 days, when an important increase of total α-AA levels was produced, the branched-chain AA being the most notable among EAA and Glu/Gln among NEAA. Later, at 50 days of starvation, total α-AA, EAA (except Leu and Ile) and NEAA decreased.
After 50 days of starvation, 12 days of refeeding did not modify the levels of EAA and NEAA, and their concentrations were lower than those of the control group, which presented an increase of total AA at this time. The differences observed on the changes of individual AA levels are discussed.     

Gonadal development and reproductive cycle of Lutjanus peru (Pisces: Lutjanidae) in Guerrero, Mexico

In this paper, aspects of the reproductive biology of Lutjanus peru that can be used for the fishery management are described. Samples were taken monthly in 1993 and 1994, from commercial catches in the southern coast of Guerrero, Mexico. A global sex ratio of 1:1.37 (M:F) was found, but the sex ratio was highly variable each month. The condition factor, gonadosomatic, hepatosomatic and stomach fullness indexes were analyzed. None of the morphophysiological indexes showed any clear tendency. From 377 gonads, both male and female, five developmental stages were characterized for each sex. L. peru shows asynchronous gonad development and multiple spawning. Two spawning period were observed in 1993 (March, and August-September) and three in 1994 (April-May, July-August, and November), with a maximum in August of both years. Length at first maturity for the females of L. peru was estimated at 295 mm fork length.     

Polyamine biosynthesis in arginine-starved and refed rats

Growth of rats fed with a synthetic diet was studied under control conditions (arginine-rich), arginine starvation, and arginine starvation/refeeding. Hepatic polyamine concentrations and ornithine decarboxylase (ODC-)activity were determined for each population. In the livers of arginine-starved rats putrescine was decreased to half the control content within 8 days; upon refeeding, it returned to control levels within another 8 days. Spermidine content in liver tissue of arginine-starved rats remained rather stable for 7 days, but thereafter dropped to half the original value within two days. Refeeding for a period of 11 days was not enough to restore the spermidine content. The effects of arginine starvation/refeeding on spermine were very similar to those of spermidine. ODC specific activity, when correlated with growth, was higher in livers of arginine-starved rats than in control animals. Refeeding caused a decrease in ODC-activity although growth arrest was completely released. This apparent uncoupling of growth and ODC stimulation supports the theory that ODC in rat liver is regulated at three levels: first the growth-related component which is observed after stimulation by growth-hormone; second the known feed back control by polyamines, e.g. via antizyme; third the regulation at the level of the substrate supply which has been shown in this work. This is not a unique finding since very similar results have been obtained in previous experiments with the protozoan Tetrahymena thermophila. A remarkable observation of these assays was that L-ornithine, when added to the arginine-free diet was not able to substitute for L-arginine in directing growth and growth related processes.     

Effect of starvation and refeeding on digestive enzyme activities in sturgeon (Acipenser naccarii) and trout (Oncorhynchus mykiss)

The digestive enzyme activities were determined in Adriatic sturgeon and rainbow trout during starvation and refeeding period. Overall, the digestive enzyme activities are affected in the same sense in both species. The protease and lipase activities were decreased later than amylase activity. Even after 1 month of starvation, both species would be prepared to digest protein and lipids in an effective way. After 72 days of starvation, the digestive machinery of the sturgeon and of the trout shows an altered capacity to digest macronutrients. The capacity to digest proteins and lipids, after 60 days of refeeding, begins to become re-established in sturgeon and trout. In contrast, in this period, the capacity to digest carbohydrates remains depressed in both species.     

The effect of energetic condition on growth dynamics and health of Atlantic cod (Gadus morhua)

Prolonged starvation resulting in sublethal condition factor values was hypothesized to have a detrimental effect on short‐term growth capacity upon refeeding. Cod (Gadus morhua) were food‐deprived and their length and mass measured before refeeding and after 3, 6, 9 and 12 weeks of ad libitum feeding. Total mass increase during the first 3 weeks of feeding was greatest in fish with a higher initial condition factor. The reverse situation was observed during the last 3 weeks of feeding. Specific growth rate peaked in the period from week 4 to week 6, except in cod with the highest condition factor for which a steady decline in specific growth rate was observed, and was not influenced by the condition factor at the start of the feeding period. Total mass increase over 12 weeks was also not influenced by initial condition factor. Thus by the end of the experiment, condition factors were lowest in fish with initially low condition factors. The hepatosomatic index and gonadosomatic index did not differ at the end of the experiment, but the proportion of mature cod increased with increasing initial condition factor. A disease outbreak caused significant mortalities among fish shortly after the start of the feeding period. Forty‐one percent of the fish had died after 84 days. No mortality was observed among fish that had started the experiment with the highest condition factor. Mortality was inversely related to initial condition factor. Growth was examined for survivors exclusively. Poor condition in wild fish may increase vulnerability to diseases and compensatory growth may not allow cod with low condition factors to fully recover unless food availability remains high over a long period of time.     

Alterations in expression of genes associated with muscle metabolism and growth during nutritional restriction and refeeding in rainbow trout

Rainbow trout, as well as many other species of fish, demonstrate the ability to survive starvation for long periods of time. During starvation, growth rate is decreased and muscle exhibits signs of wasting. However, upon resumption of feeding, accelerated growth is often observed. Alterations in muscle metabolism occur during feed restriction and refeeding, although the ways in which these alterations affect the molecular pathways that control muscle growth have not been fully determined. To analyze changes in muscle metabolism and growth during starvation and refeeding, real-time PCR was used to test the expression of six metabolic-related genes and eight muscle-specific genes in rainbow trout white muscle prior to and after 30 days of starvation, and after 4 and 14 days of refeeding. The six metabolic-related genes chosen are indicative of specific metabolic pathways: glycolysis, glycogenesis, gluconeogenesis, the pentose phosphate pathway, and fatty acid formation. The eight muscle specific genes chosen are key components in muscle growth and structural integrity, i.e., MRFs, MEFs, myostatins, and myosin. Alterations in expression of the tested metabolic-related genes and muscle-specific genes suggest that during both starvation and refeeding, changes in specific metabolic pathways initiate shifts in muscle that result mainly in the modification of myotube hypertrophy. The expression levels of many of the metabolic-related genes were altered during the refeeding period compared to those observed before the starvation period began. However, the accelerated growth often observed during refeeding is likely driven by changes in normal muscle metabolism, and the altered expression observed here may be a demonstration of those changes.     

Selected plasma biochemistry parameters in gilthead seabream (Sparus aurata) juveniles

The aim of this study was to assess plasma biochemistry parameters with the potential of being used as indicators of the nutritional status for healthy gilthead seabream juveniles. Triplicate groups of 18 seabream (body weight of 58 g) were kept unfed for 24 h, 7 or 14 days. Nine fish per treatment were then sampled randomly for blood collection and the following parameters analyzed in the plasma using standard clinical methods: glucose; protein; triglycerides; cholesterol; calcium; magnesium; inorganic phosphorus; alkaline phosphatase (ALP); aspartate aminotransferase (AST); lactate dehydrogenase (LDH); gamma‐glutamyl transferase (GGT); creatine phosphokinase (CPK); and lipase. Biochemical parameters showed lower variability among individuals than did enzymatic parameters. Plasma glucose, protein, cholesterol, calcium and inorganic phosphorus levels were inversely related to the duration of starvation. On the contrary, plasma triglycerides decreased significantly during the first week of starvation and remained stable in the second week. Plasma ALP, AST and LDH decreased significantly after 1 week of starvation and then remained constant. In healthy seabream juveniles, plasma glucose, protein, cholesterol, calcium and inorganic phosphorus are responsive to starvation and may be useful indicators of the nutritional status of the animals. Indicative baseline reference values for gilthead seabream juveniles starved for 24 h and held at optimum temperature are: protein, 3.7–4.9 g dl^?1; cholesterol, 341–407 mg dl^?1; calcium, 13.1–8.0 mg dl^?1; and inorganic phosphorus, 10–14.2 mg dl^?1. Plasma triglycerides, along with plasma enzyme activities, may be useful as indicators of short term starvation. For these parameters baseline values after 1 week of starvation were: triglycerides: 138–230 mg dl^?1; ALP: 58–125 U L^?1; AST: 15–127 U L^?1; and LDH 61–677 U L^?1. Plasma glucose is only responsive to longer starvation periods, remaining relatively stable during the first week of starvation, and ranging from 59 to 196 mg dl^?1.     

The metabolic effects of prolonged starvation and refeeding in sturgeon and rainbow trout

The present study examines the particular metabolic strategies of the sturgeon Acipenser naccarii in facing a period of prolonged starvation (72 days) and subsequent refeeding (60 days) compared to the trout Oncorhynchus mykiss response under similar conditions. Plasma metabolites, endogenous reserves, and the activity of intermediate enzymes in liver and white muscle were evaluated. This study shows the mobilization of tissue reserves during a starvation period in both species with an associated enzymatic response. The sturgeon displayed an early increase in hepatic glycolysis during starvation. The trout preferentially used lactate for gluconeogenesis in liver and white muscle. The sturgeon had higher lipid-degradation capacity and greater synthesis of hepatic ketone bodies than the trout, although this latter species also showed strong synthesis of ketone bodies during starvation. During refeeding, the metabolic activity present before starvation was recovered in both fish, with a reestablishment of tissue reserves, plasmatic parameters (glucemia and cholesterol), and enzymatic activities in the liver and muscle. A compensatory effect in enzymes regarding lipids, ketone bodies, and oxidative metabolism was displayed in the liver of both species. There are metabolic differences between sturgeon and trout that support the contention that the sturgeon has common characteristics with elasmobranchs and teleosts.     

Effect of a Selective Cyclooxygenase Type 2 Inhibitor Celecoxib on Depression Associated with Obesity in Mice: An Approach Using Behavioral Tests

The biological mechanisms that link the development of depression to metabolic disorders such as obesity and diabetes remain ambiguous. In the present study the potential of a selective cyclooxygenase inhibitor celecoxib (15 mg/kg p.o.) was investigated in depression associated with obesity in mice. Behavioral tests used to assess depressive-like behavior were sucrose preference test, forced swim test (FST), tail suspension test (TST) and elevated plus maze (EPM). The basal locomotor score in obese mice was not altered. Furthermore, estimation of biochemical parameters was performed for plasma glucose, total cholesterol, triglycerides and total proteins. Escitalopram (10 mg/kg p.o.) served as reference standard drug. In the results, chronic treatment with celecoxib for 28 days significantly attenuated the behavioral alterations as indicated by increased the sucrose consumption, reduced the immobility time in FST and TST, increased the percent open arm time and entries in EPM in obese mice. In the biochemical parameters celecoxib significantly reversed the increased plasma glucose, total cholesterol, triglycerides and total proteins in obese mice. In conclusion, celecoxib exhibited potential antidepressant-like effect in depression associated with obesity, which to some extent is mediated by reversing the altered plasma glucose in obese mice.     

Changes in glucose,glycogen, thyroid activity and hypothalamic catecholamines in tench by starvation and refeeding

The effects of short-term food deprivation (7 days) and refeeding (2 days) on different biochemical and neuroendocrine parameters were studied in tench. A 7-days fast resulted in a significant reduction of plasma glucose and glycogen hepatic content, supporting the key role of liver glycogen as energy depot for being consumed during fasting. The rapid recovery of normal values of blood glucose and glycogen stores by refeeding indicates a rapid replenishment of liver glycogen stores. The short-term starvation decreased circulating thyroid hormones (both T3 and T4) and T4 release from thyroid, supporting an interaction between nutritional state and thyroid function in tench. All these metabolic and hormonal changes were partial or totally reversed under refeeding conditions. An increase in hypothalamic content of norepinephrine and dopamine was found in fasted fish. This result might be a consequence of stress induced by starvation.     

Seasonal changes in serum glucose and condition of the plaice, Pleuronectes platessa L.

Monthly sampling of plaice caught off the north-east coast of Scotland between February 1983 and May 1984 revealed a seasonal increase in condition factor, hepatosomatic index and serum glucose, which appeared to be related to the period of active feeding. The spleen indices followed a similar seasonal increase, although this was not statistically significant, while the kidney indices showed little change over the 16 months. The peak for the gonadosomatic index was in February/March 1984, but among these plaice (aged 4–5 years) there were still large numbers of immature males and females and there was no increase in 1983. Apart from the hepatosomatic index for January 1984, there was no significant difference between male and female plaice.     

Effect of starvation and refeeding on the circadian rhythms of hematological and clinico-biochemical values, and water intake of rats

We investigated the effect of starvation for 24 hr and subsequent refeeding for 12 hr on the circadian rhythms of 39 hematological and clinico-biochemical parameters, and water intake of F344 rats. The rats scarcely drank any water during the starvation period, but subsequently their intake of water were normal, even in the light period. During starvation, 12 parameters such as serum levels of alkaline phosphatase activity and PaCO2 decreased with time-related and time-related increases of 8 parameters such as the erythrocyte count and cholinesterase activity. During refeeding for 12 hr, almost all these biochemical parameters were normalized, but none of the hematological values except the leukocyte count returned to normal levels. Starvation and refeeding had little affect on the circadian rhythms of others.     

Compensatory growth in sub‐yearling Siberian sturgeon,Acipenser baerii Brandt, 1869: Effects of starvation and refeeding on growth,feed utilization and body composition

The capacity of sub‐yearling Siberian sturgeon (Acipenser baerii Brandt, 1869) (19.7 ± 0.8 g) to show compensatory growth was assessed for a 40‐day period for the effects of short‐term starvation and refeeding on growth, feeding performance and body composition. After acclimation, 25 experimental fish were randomly distributed among twelve 500‐L cylindrical fiberglass tanks with a flow‐through system. The fish were subjected to four different feeding regimes: control, which was fed four times daily to apparent satiation; T₁: four periods of 2 days starvation alternating with 8 days re‐feeding; T₂: two periods of 4 days starvation alternating with 16 days refeeding; T₃: an 8 days starvation period followed by 32 days refeeding. At the end of the experiment, the deprived fish attained body weights comparable to those attained by the control fish. There were no differences in growth and feeding performances between the deprived and the control fish. Total protein and lipid contents of the control fish were significantly higher than that of T₁ and T₂ fish at the end of the experiment (P < 0.05). A significant difference in the energy content was observed between T₂ and the control. Siberian sturgeon exhibited complete compensation, indicating a high ability of the deprived fish to grow sufficiently to fully compensate for weight loss during starvation. The results suggested that the feeding schedule involving starvation–refeeding cycles could be a promising feed management option for the culture of this species.     

The Effects of Dietary Iron and Capsaicin on Hemoglobin,Blood Glucose,Insulin Tolerance,Cholesterol, and Triglycerides,in Healthy and Diabetic Wistar Rats

ObjectiveOur aim was to assess the effects of dietary iron, and the compound capsaicin, on hemoglobin as well as metabolic indicators including blood glucose, cholesterol, triglycerides, insulin, and glucose tolerance.ResultsHealthy rats fed a low-iron diet exhibited significantly reduced total cholesterol and triglyceride levels, compared with rats fed a control diet. Significantly reduced blood lipid was also provoked by low dietary iron in diabetic rats, compared with those fed a control diet. Insulin, and glucose tolerance was only improved in healthy rats fed the low-iron diet. Significant increases in total cholesterol were found in diabetic rats fed a high-iron diet, compared with healthy rats fed the same diet, although no statistical differences were found for triglycerides. Hemoglobin levels, which were not statistically different in diabetic versus healthy rats fed the high-iron diet, fell when capsaicin was added. Capsaicin also provoked a fall in the level of cholesterol and triglycerides in diabetic animals, versus diabetics fed with the high iron diet alone. In conclusion, low levels of dietary iron reduced levels of serum triglycerides, hemoglobin, and cholesterol, and significantly improved insulin, and glucose tolerance in healthy rats. In contrast, a high-iron diet increased cholesterol significantly, with no significant changes to triglyceride concentrations. The addition of capsaicin to the high-iron diet (for diabetic rats) further reduced levels of hemoglobin, cholesterol, and triglycerides. These results suggest that capsaicin, may be suitable for the treatment of elevated hemoglobin, in patients.