Purified chickpea or lentil proteins impair VLDL metabolism and lipoprotein lipase activity in epididymal fat, but not in muscle, compared to casein, in growing rats.

BACKGROUND: It is well known that the legume proteins have a lowering effect on plasma cholesterol and triacylglycerols (TG) concentrations compared to animal proteins. The protein itself, as well as non-protein constituents, naturally present in legumes may be implicated. AIM OF THE STUDY: The effects of various dietary purified legumes proteins compared to casein, were determined on plasma TG level, VLDL concentration and composition. Moreover, lipoprotein lipase (LPL) activity in epididymal fat, gastrocnemius and heart was investigated to evaluate in these tissues their capacity to release free fatty acids from their TG substrate and the liver capacity to stock the TG. METHODS: Weaning male Wistar rats were fed ad libitum one of the following diets: 200 g/kg diet of purified proteins of lentil (L), or chickpea (CP) or casein (CAS). At day 28, VLDL were isolated from plasma sample by a single ultracentrifugation flotation. Hepatic lipase and LPL activity in epididymal fat, gastrocnemius and heart were measured by using glycerol tri [9-10(n)-(3)H] oleate emulsion as substrate. RESULTS: Compared with CAS diet, the CP and L protein diets exhibited similar cholesterolemia, but lower triglyceridemia (1.9-fold and 2.5-fold) and VLDL particle number, as measured by their reduced contents of TG and apolipoproteins. CP and L protein diets reduced liver TG and cholesterol by 31 and 45%, respectively compared to CAS diet. Furthermore, LPL activity in adipose tissue of rats fed CP or L was 1.6-fold lower than that of rats fed CAS. There was no significant difference in heart and gastrocnemius LPL activities with the three proteins. In contrast, hepatic lipase activity was higher in rats fed CP and L diets. CONCLUSION: The low food efficiency ratio of purified CP and L proteins related to CAS is associated with decreased plasma VLDL and adipose tissue LPL activity. The low liver TG concomitant with reduced TG and apolipoproteins contents of VLDL confirm that hypotriglyceridemia is essentially due to impaired synthesis, exportation and transport of TG by VLDL which prevent lipid storage in adipose tissue.

Long term hemodialysis aggravates lipolytic activity reduction and very low density, low density lipoproteins composition in chronic renal failure patients.

BACKGROUND: Dyslipidemia, particularly hypertriglyceridemia is common in uremia, and represents an independent risk factor for atherosclerosis. METHODS: To investigate the effects of hemodialysis (HD) duration on very low density lipoprotein (VLDL) and low density lipoprotein (LDL) compositions and lipopolytic activities, 20 patients on 5 to 7 years hemodialysis were followed-up during 9 years. Blood samples were drawn at T0 (beginning of the study), T1 (3 years after initiating study), T2 (6 years after initiating study) and T3 (9 years after initiating study). T0 was taken as reference. RESULTS: Triacylglycerols (TG) values were correlated with HD duration (r = 0.70, P < 0.05). An increase of total cholesterol was noted at T2 and T3. Lowered activity was observed for lipoprotein lipase (LPL) (-44%) at T3 and hepatic lipase (HL) (-29%) at T1, (-64%) at T2 and (-73%) at T3. Inverse relationships were found between HD duration and LPL activity (r = -0.63, P < 0.05), and HL activity (r = -0.71, P < 0.01). At T1, T2 and T3, high VLDL-amounts and VLDL-TG and decreased VLDL-phospholipids values were noted. Increased LDL-cholesteryl esters values were noted at T1 and T2 and in LDL-unesterified cholesterol at T2 and T3. CONCLUSION: Despite hemodialysis duration, VLDL-LDL metabolism alterations are aggravated submitting patients to a greater risk of atherosclerosis.

The essential oil of turpentine and its major volatile fraction (alpha- and beta-pinenes): a review.

This paper provides a summary review of the major biological features concerning the essential oil of turpentine, its origin and use in traditional and modern medicine. More precisely, the safety of this volatile fraction to human health, and the medical, biological and environmental effects of the two major compounds of this fraction (alpha- and beta-pinenes) have been discussed.

Antioxidant activity of Bol d'Air Jacquier breathing sessions in Wistar rats--first studies.

OBJECTIVES: The Bol d'Air Jacquier is used to create a molecule able to deliver oxygen at the cellular level to manage hypoxia due to environmental pollution, ageing, or inflammatory disease. This study was designed to determine, firstly, whether the device generated oxidative stress and, secondly, whether it might induce an antioxidant effect. MATERIAL AND METHODS: Over a period of 62 weeks, 10 male Wistar rats were randomized into two groups: the Bol d'Air group (BA) regularly breathed peroxidizing terpens delivered by the device and the control group breathed water vapour during 9-min sessions, at the frequency of 1-12 per month. Several antioxidant compounds and KRL levels were determined in the blood and major organs. RESULTS: The results showed that the two groups did not differ with respect to the organ concentrations of Cu, Zn SOD, GPx, GSH, GSSG and TBARS. The device might have a weak slimming effect over time. The BA group presented a significantly higher GR level in plasma throughout the experiment, and in the muscle at the end of the study. In the BA group, the plasma Cu, Zn SOD level was related to the number of breathing sessions per week before blood collection. The BA group also had a higher KRLantioxidant status at two different time-points: at the onset of the study, in the blood of young rats; and after three breathing sessions per week, in the blood and RBCs of old rats. CONCLUSIONS: The device did not generate oxidative stress and seemed to produce global antioxidant effect depending on the number of sessions per week, especially in old rats.

An experimental manipulation of life-history trajectories and resistance to oxidative stress.

Optimal investment into life-history traits depends on the environmental conditions that organisms are likely to experience during their life. Evolutionary theory tells us that optimal investment in reproduction versus maintenance is likely to shape the pattern of age-associated decline in performance, also known as aging. The currency that is traded against different vital functions is, however, still debated. Here, we took advantage of a phenotypic manipulation of individual quality in early life to explore (1) long-term consequences on life-history trajectories, and (2) the possible physiological mechanism underlying the life-history adjustments. We manipulated phenotypic quality of a cohort of captive zebra finches (Taeniopygia guttata) by assigning breeding pairs to either an enlarged or a reduced brood. Nestlings raised in enlarged broods were in poorer condition than nestlings raised in reduced broods. Interestingly, the effect of environmental conditions experienced during early life extended to the age at first reproduction. Birds from enlarged broods delayed reproduction. Birds that delayed reproduction produced less offspring but lived longer, although neither fecundity nor longevity were directly affected by the experimental brood size. Using the framework of the life-table response experiment modeling, we also explored the effect of early environmental condition on population growth rate and aging. Birds raised in reduced broods tended to have a higher population growth rate, and a steeper decrease of reproductive value with age than birds reared in enlarged broods. Metabolic resources necessary to fight off the damaging effect of reactive oxygen species (ROS) could be the mechanism underlying the observed results, as (1) birds that engaged in a higher number of breeding events had a weaker red blood cell resistance to oxidative stress, (2) red blood cell resistance to oxidative stress predicted short-term mortality (but not longevity), and (3) was related with a parabolic function to age. Overall, these results highlight that early condition can have long-term effects on life-history trajectories by affecting key life-history traits such as age at first reproduction, and suggest that the trade-off between reproduction and self-maintenance might be mediated by the cumulative deleterious effect of ROS.

Cassava-enriched diet is not diabetogenic rather it aggravates diabetes in rats.

Chronic intake of cassava has been thought to play a role in the pathogenesis of diabetes. We investigated the effects of dietary cassava (Manihot esculenta), which naturally contains cyanogenic glycosides, in the progression of diabetes mellitus in rats. Diabetes was induced by five mild doses of streptozotocin, in male Wistar rats which were fed a standard or cyanide-free cassava (CFC) diet containing or not containing exogenous cyanide with or without methionine. Methionine was employed to counterbalance the toxic effects of cyanide. During diabetes progression, we determined glycaemia and antioxidant status, by measuring vitamin C levels and activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and glutathione reductase (GSSG-Red). Feeding CFC diet did not induce diabetes in control rats; rather this diet, in diabetic animals, aggravated hyperglycaemia the severity of which was increased in these animals fed CFC diet, supplemented with cyanide. Addition of methionine curtailed the toxic effects of cyanide supplementation in CFC diet-fed diabetic animals. In standard diet-fed animals, the activities of SOD, GSH-Px and GSSG-Red were lower in diabetic rats than control rats. Interestingly, all of the CFC diets with or without cyanide or methionine, increased vitamin C levels and antioxidant enzyme activities in both control and diabetic animals. However, supplementing cyanide to CFC diet (without methionine) curtailed SOD and GSH-Px activities in diabetic rats. Our study shows that cassava diet containing cyanide is 'diabetes-aggravating'.

Fructose-enriched diet modifies antioxidant status and lipid metabolism in spontaneously hypertensive rats.

OBJECTIVE: High-fructose consumption in industrial countries has been shown to induce metabolic abnormalities or syndrome X. Changes in antioxidant defense are unknown in hypertension associated with metabolic disorders induced by high-fructose feeding. METHODS: Twenty spontaneously hypertensive rats were assigned to one of two groups; one received a fructose-enriched diet (60% fructose) and the other a starch diet. After a 13-wk diet period, total antioxidant status was assessed in the blood and liver by monitoring the rate of free radical-induced red blood cell hemolysis. Antioxidants (enzymes and vitamins) were determined in blood and liver. Gene expression of antioxidant enzymes (copper/zinc superoxide dismutase and glutathione peroxidase) were also investigated in hepatic tissue. RESULTS: Fructose-fed rats showed blood pressure values similar to that of control rats but had increased glycemia and insulinemia. The antioxidant capacity in the blood of the fructose-fed group represented by copper/zinc superoxide dismutase and glutathione peroxidase activities and ascorbic acid was lower. However, the fructose diet enhanced the total antioxidant capacity of liver correlated with increased antioxidant enzyme activities and retinol concentrations. Gutathione peroxidase mRNA expression was decreased in livers of spontaneously hypertensive rats fed the fructose diet. CONCLUSION: Fructose feeding negatively affects antioxidant capacity in the blood of hypertensive rats but improves this capacity in the liver.

Changes in lipid metabolism and antioxidant defense status in spontaneously hypertensive rats and Wistar rats fed a diet enriched with fructose and saturated fatty acids.

OBJECTIVE: Larger doses of fructose and saturated fat have been associated with oxidative stress and development of hypertension. The effects of modest amounts of fructose and saturated fatty acids on oxidative stress are unknown. METHODS: To increase knowledge on this question, 10-wk-old spontaneously hypertensive rats and Wistar rats were fed for 8 wk with a control diet or an experimental diet enriched with fructose (18%) and saturated fatty acids (11%; FS diet). The total antioxidant status of organs and red blood cells was assayed by monitoring the rate of free radical-induced red blood cell hemolysis. Sensitivity of very low-density lipoprotein and low-density lipoprotein (VLDL-LDL) to copper-induced lipid peroxidation was determined as the production of thiobarbituric acid-reactive substances. Antioxidant enzymes and vitamins were also measured to establish the oxidative stress effect. RESULTS: The FS diet did not affect blood pressure in either strain, but it increased plasma insulin concentrations only in Wistar rats without affecting those of glucose of either strain. The FS diet significantly enhanced plasma and VLDL-LDL triacylglycerol concentrations without affecting concentrations of VLDL-LDL thiobarbituric acid-reactive substances. The decreased content of arachidonic acid and total polyunsaturated fatty acids in VLDL-LDL by the FS diet may have prevented lipid peroxidation in this fraction. Moreover, FS consumption by both strains was accompanied by a significant increase in total antioxidant capacity of adipose tissue, muscle, heart, and liver. This may have resulted from increased tissue ascorbic acid levels and glutathione peroxidase and glutathione reductase activities in tissues. CONCLUSIONS: These findings clearly indicate that the FS diet did not alter blood pressure of spontaneously hypertensive rats and Wistar rats. The FS diet resulted in hypertriglyceridemia but increased the total antioxidant status, which may prevent lipid peroxidation in these rats.

An experimental test of the dose-dependent effect of carotenoids and immune activation on sexual signals and antioxidant activity.

Carotenoid-based sexual traits are thought to be reliable indicators of male quality because they might be scarce and therefore might indicate the ability of males to gather high-quality food and because they are involved in important physiological functions (as immune enhancers and antioxidants). We performed an experiment where male and female zebra finches (Taeniopygia guttata) were provided with increasing carotenoid doses in the drinking water during 4 weeks (bill color of this species is a carotenoid-based sexual signal). Simultaneously, birds were split into two groups: one receiving weekly injections of Escherichia coli lipopolysaccharide in order to activate the immune system, the other being injected with the same volume of phosphate buffered saline. We assessed how carotenoid availability and immune activation affected the amount of circulating plasma carotenoids, the beak color, and the antioxidant defenses (assessed as the resistance of red blood cells to a controlled free radical attack). Carotenoid availability affected the amount of circulating carotenoids and beak color; both variables reached a plateau at the highest carotenoid doses. Immune activation diverted carotenoids from plasma, and this in turn affected the expression of the sexual trait. Finally, we found a positive correlation between the change in circulating carotenoids and antioxidant defenses. These results support the idea that carotenoids have important physiological properties that ensure the honesty of carotenoid-based sexual traits.

Plasma lipoprotein lipase, hepatic lipase activities, VLDL, LDL compositions at different times of hemodialysis.

The effects of hemodialysis duration (HD) on lipoprotein lipase (LPL) and hepatic lipase (HL) activities and very low density lipoprotein (VLDL), low density lipoproteins (LDL) amounts and compositions were investigated in 58 patients, divided according to HD: GI: under 1 year, GII: 1-5 years, GIII: 5-13 years. HL and LPL activities were reduced in GIII versus GI (P<0.01) and 47% of GIII patients had negligible HL activity. LPL and HL activities were correlated with HD (r=-0.80, P<0.001). Apo C-III concentrations were correlated with HD (r=0.58, P<0.05). Compared with controls, triacylglycerols (TG) were increased in GI, GII (P<0.01) and GIII (P<0.001), and were correlated with HD (r=0.75, P<0.05). VLDL amounts and VLDL-cholesteryl esters (CE) were enhanced in GIII versus GI and GII (P<0.05). VLDL-TG and VLDL-phospholipids (PL) were correlated with HD (r=0.60, P<0.05). LDL-apolipoproteins and unesterified cholesterol (UC) were increased in GII versus GI (P<0.05) and in GIII versus GII and GI (P<0.01). LDL-PLs were decreased in GIII versus GI (P<0.05). Compared with controls, LDL-TGs were higher in GI and GII (P<0.01) and in GIII (P<0.05). Long-term treatment with acetate hemodialysis using cuprophane membrane does not improve lipolytic activity decrease and lipoprotein alterations generated by chronic renal failure (CRF).

Changes in serum lipoprotein lipids and their fatty acid compositions and lipid peroxidation in growing rats fed soybean protein versus casein with or without cholesterol.

OBJECTIVE: We compared the effects of diets based on soybean protein and casein supplemented or not supplemented with 0.1% cholesterol on plasma lipoprotein lipid amounts and their fatty acid compositions, lecithin:cholesterol acyl-transferase activity, and lipid peroxidation. METHODS: The composition and concentration of lipid and apolipoprotein in different lipoprotein classes, plasma LCAT activity, and lipid peroxidation were determined in rats fed 20% highly purified soybean protein or casein with or without 0.1% cholesterol for 2 mo. RESULTS: Soybean protein and casein diets with or without cholesterol had similar plasma total cholesterol concentrations. Soybean protein consumption diminished very low-density lipoprotein particle number, as measured by diminished contents of very low-density lipoprotein triacylglycerol, phospholipid, and apolipoprotein-B100. Lecithin:cholesterol acyl-transferase activity was not significantly modified by either protein. The soybean protein diet decreased the linoleate desaturation index (20:4[omega-6]/18:2[omega-6]) in liver and high-density lipoprotein fraction 2-3-phospholipids but enhanced red blood cell resistance against free radical attack. Addition of cholesterol to both protein diets decreased concentrations of high-density lipoprotein fraction 2-3 cholesterol. Lecithin:cholesterol acyl-transferase activity tended to be greater after cholesterol feeding, likely due to the enhanced high-density lipoprotein fraction 2-3 apolipoprotein-AI, a cofactor activator for lecithin:cholesterol acyl-transferase. Regardless of dietary protein source, cholesterol supplementation decreased the linoleate desaturation index in liver and plasma lipoprotein lipids and red blood cell resistance to free radical attack. CONCLUSIONS: Our results suggest that the dietary protein origin affects lipid peroxidation and polyunsaturated fatty acid biosynthesis and distribution among liver and different lipoprotein lipid classes, but plays only a minor role in the regulation of plasma and lipoprotein cholesterol concentrations. Providing dietary cholesterol (0.1%) with casein or soybean protein attenuates the effects of these proteins, with the exception of plasma cholesterol.

Dietary fish protein lowers blood pressure and alters tissue polyunsaturated fatty acid composition in spontaneously hypertensive rats.

OBJECTIVE: To investigate the effect of two types of dietary protein on blood pressure, liver fatty acid desaturation and composition, and urine 6-keto-prostaglandin-F (PGF(1alpha)) level, the metabolite of prostacyclin. METHODS: 5-wk-old spontaneously hypertensive rats were fed 20% casein or purified fish protein. The fat source was 5% ISIO oil, which contains 47.9% (omega-6) and 1.7% (omega-3) total polyunsaturated fatty acids. After 2 mo on the diet, systolic blood pressure was reduced with fish protein compared with casein (189.8 +/- 10.5 versus 220.7 +/- 8.7). RESULTS: Excretion of 6-keto-PGF(1alpha) in urine was negatively correlated with blood pressure. Liver cholesterol and phospholipid concentrations were 1.71- and 1.27-fold lower with fish protein than with casein, respectively. The fish protein diet lowered the 20:4(omega-6) proportion and the ratio of 20:4(omega-6) to 18:2(omega-6) in liver microsomal lipids and phospholipids, which was due to the reduced microsomal Delta6(omega-6) desaturation activity. Dietary protein source did not affect omega-3 fatty acid composition, and this was associated with a similar activation of Delta6(omega-3) desaturation in liver microsomes. CONCLUSIONS: The present data indicated a significant blood pressure-lowering effect caused by fish protein, rather than by casein, that modified the fatty acid composition of liver phospholipids and liver microsomal total lipids.

Impaired lipoprotein metabolism in obese offspring of streptozotocin-induced diabetic rats.

The time course of changes in lipoprotein metabolism of obese offspring of mildly diabetic rats was studied with respect to serum lipoprotein composition as well as LCAT and tissue lipoprotein lipase (LPL) activities. Mild hyperglycemia in pregnant rats was induced by intraperitoneal injection of streptozotocin on day 5 of gestation. Control pregnant rats were injected with citrate buffer. At birth, obese pups had higher serum glucose, insulin, and lipoprotein (VLDL, LDL-HDL1, HDL(2-3)) levels than control pups. After 1 mon of life, all of these parameters in obese rats became similar to those of controls. However, LCAT, adipose tissue LPL, and hepatic triacylglycerol lipase activities were high. At 2 mon of age, VLDL-TAG levels were higher in obese females than in controls. By the age of 3 mon, obese offspring had developed insulin resistance with hyperglycemia, hyperinsulinemia, and higher serum lipoprotein concentrations. Indeed, qualitative abnormalities of lipoproteins were seen and were typical of obese and diabetic human beings. Fetal hyperinsulinemia should be considered as a risk factor for later metabolic diseases, including dyslipoproteinemia.

A well-oxygenated cells environment may help to fight against protein glycation.

OBJECTIVES: Normoglycemic Wistar rats' Glycated Hemoglobin Levels (GHL) showed a time-dependent difference between control groups and those exposed to regular inhalation of peroxidizing extracts of turpentine. These extracts were able to optimize the oxygen permeation at the cellular level during and subsequently to a breathing session. The more the rats breathed turpentine peroxidized vapor, the lower their GHL was. This study was designed to confirm, in ex-vivo blood samples, the impact of peroxidizing extract on the GHL. MATERIALS AND METHODS: Red blood cells were separated from plasmas by centrifugation. Plasmas were treated by peroxidizing and non-peroxidizing turpentine vapor or untreated (control), then combined with washed red blood cells three hours before evaluation. Glycation of hemoglobin proteins was quantified according to the Habeed's method. RESULTS: The ex-vivo experiments showed that the peroxidizing terpenes reduced the GHL after a three-hour contact. So did oxidized terpenes. Controls and the volatile component of the expended essential oil showed the opposite results. CONCLUSION: Optimal oxygenation, especially when facilitated by the peroxidized volatile component of the essential oil of turpentine, can protect organisms (mammals in this study) from protein glycation. Optimizing oxygenation can also reduce the GHL of treated blood samples after three hours of incubation.

Iridoid extracts from Ajuga iva increase the antioxidant enzyme activities in red blood cells of rats fed a cholesterol-rich diet.

The lyophilized aqueous extract of Ajuga iva (Ai) is able to reduce oxidative stress, which may prevent lipid peroxidation in hypercholesterolemic rats. Iridoids (I) were isolated from Ai. We hypothesized that the antioxidant defense status in red blood cells (RBC) and tissues in rats fed a cholesterol-rich diet and treated with Ai may be correlated to these compounds. Male Wistar rats (n = 32) weighing 120 +/- 5 g were fed a diet containing 1% cholesterol for 15 days. After this phase, hypercholesterolemic (HC) rats were divided into groups, fed the same diet, and received either the same or different doses (5, 10, or 15 mg/kg body weight by intraperitoneal injection) of I for 15 days. Compared with the HC group, total cholesterol value was 1.4- and 1.2-fold lower in the I(5)-HC and I(10)-HC groups. Serum thiobarbituric acid reactive substance content was 2.3-, 2.9-, and 3-fold lower in the I(5)-HC, I(10)-HC, and I(15)-HC groups compared with the HC group. In RBC, glutathione peroxidase, glutathione reductase, and superoxide dismutase activities were significantly higher in the I(5)-HC, I(10)-HC, and I(15)-HC groups than the HC group. Liver, heart, and muscle glutathione peroxidase and superoxide dismutase activities were significantly higher in the groups treated with I than the HC group. Muscle glutathione reductase activity was increased 1.4-fold in the I(5)-HC, 1.5-fold in the I(10)-HC, and 1.5-fold in the I(15)-HC group. In HC rats, different doses of I increase the antioxidant enzyme activities in RBC and act differently in tissues. Treatment with I may play an important role in suppressing oxidative stress caused by dietary cholesterol and, thus, may be useful for the prevention and/or early treatment of hypercholesterolemia.

Oxygen recovery up-regulates avian UCP and ANT in newly hatched ducklings.

At hatching, breaking eggshell induces a surge in oxygen availability that is likely to generate oxidative stress in newborn chicks. To investigate the involvement of potential adaptive antioxidant mechanisms, we explored some markers of oxidative stress and the regulation of muscle avian uncoupling protein (avUCP) and adenine nucleotide translocase (ANT) in ducklings in the peri-hatching period. When compared with pre-hatching levels, the amount of peroxidized lipids were increased 24 h after external pipping in gastrocnemius muscle (+37%) and heart (+39%) as well as the muscle avUCP mRNA expression (+60%) but the susceptibility of red blood cells to free radicals (a functional test of oxidative status) was not affected. In order to relate these changes to the oxidative transition of hatching, an imposed hypoxia/re-oxygenation protocol was used. Hatched chicks that had spent the last 24 h of incubation in artificial severe hypoxia showed a rise in muscle (+50%) and heart (+69%) lipid peroxidation, an increased susceptibility of red blood cells to free radicals, a marked over-expression of avUCP mRNA (+105%) and a rise in mitochondrial ANT content (+54%). These results suggest that avian UCP and ANT may contribute to prepare incubating eggs to the oxidative stress generated by the hypoxia/re-oxygenation transition naturally occurring at hatching.

Environmental stress affects the expression of a carotenoid-based sexual trait in male zebra finches.

Abiotic factors including thermal stress are suggested to exert constrains on sexual ornaments through trade-offs between sexual displays and physiological functions related to self-maintenance. Given the health properties of carotenoid pigments, carotenoid-based ornaments offer a relevant context in which to investigate the effect of environmental stress, such as ambient temperature, on the production and maintenance of secondary sexual traits and, also, to explore the proximate mechanisms shaping their expression. In this study, we exposed male zebra finches (Taeniopygia guttata) to environmental stress by exposing them to two temperature regimes (6 and 26 degrees C) over a 4 week period. Simultaneously, half of the males in each temperature group were supplemented with carotenoids, whereas the other half were not. The expression of a carotenoid-based sexual trait (bill colour) and the amount of circulating carotenoids were assessed before and at the end of the experiment. Carotenoid-supplemented males developed a redder bill, but the effect of supplementation was reduced under cold exposure. However, we found evidence that birds facing a cold stress were carotenoid limited, since supplemented males developed redder bills than the non-supplemented ones. Interestingly, while cold-exposed and non-supplemented males developed duller bills, they circulated a higher amount of carotenoids at the end of the experiment compared to the pre-experimental values. Together, these results suggest that ambient temperature might contribute to the modulation of the expression of carotenoid-based ornaments. Our findings suggest that carotenoids are a limiting resource under cold exposure and that they might be prioritized for self-maintenance at the expense of the ornament. The physiological functions related to self-maintenance that might have benefited from carotenoid saving are discussed.

Antioxidant status and circulating lipids are altered in human gestational diabetes and macrosomia.

Fetuses from mothers with gestational diabetes are at increased risk of developing neonatal macrosomia and oxidative stress. We investigated the modulation of antioxidant status and circulating lipids in gestational diabetic mothers and their macrosomic babies and in healthy age-matched pregnant women and their newborns. The serum antioxidant status was assessed by employing anti-radical resistance kit (KRL; Kirial International SA, Couternon, France) and determining levels of vitamin A, C, and E and the activity of superoxide dismutase (SOD). Circulating serum lipids were quantified, and lipid peroxidation was measured as the concentrations of serum thiobarbituric acid-reactive substances (TBARS). As compared with non-diabetic mothers, gestational diabetic women exhibited decreased levels of vitamin E and enhanced concentrations of vitamin C without any changes in vitamin A. Vitamin A and C levels did not change in macrosomic babies except vitamin E whose levels were lower in these infants than in the newborns of non-diabetic mothers. Gestational diabetes mellitus (GDM) and macrosomia were also associated with impaired SOD activities and enhanced TBARS levels. Globally, total serum antioxidant defense status in diabetic mothers and their macrosomic babies was diminished as compared with control subjects. Triglyceride and cholesterol concentrations did not differ significantly between gestational diabetic and control mothers; however, macrosomia was associated with enhanced plasma cholesterol and triglyceride levels. These results suggest that human GDM and macrosomia are associated with downregulation of antioxidant status, and macrosomic infants also exhibit altered lipid metabolism.

Carotenoids modulate the trade-off between egg production and resistance to oxidative stress in zebra finches.

The allocation of resources to reproduction and survival is a central question of studies of life history evolution. Usually, increased allocation to current reproduction is paid in terms of reduced future reproduction and/or decreased survival. However, the proximal mechanisms underlying the cost of reproduction are poorly understood. Recently, it has been shown that increased susceptibility to oxidative stress might be one of such proximate links between reproduction and self-maintenance. Organisms possess a range of antioxidant defenses, including endogenously produced molecules (e.g., enzymes) and compounds ingested with food (e.g., carotenoids). If reproductive effort increases the production of reactive oxygen species, the availability of antioxidant defenses may partly or fully counteract the free-radical damages. One could, therefore, expect that the trade-off between reproduction and oxidative stress is modulated by the availability of antioxidant defenses. We tested this hypothesis in zebra finches. We manipulated reproductive effort by either allowing or preventing pairs to breed. Within each breeding or non-breeding group, the availability of antioxidant compounds was manipulated by supplementing or not supplementing the drinking water with carotenoids. We found that although birds in the breeding and non-breeding groups did not differ in their resistance to oxidative stress (the breakdown of red blood cells submitted to a controlled free-radical attack), one aspect of breeding effort (i.e., the number of eggs laid by birds in both breeding and non-breeding groups) was negatively correlated with resistance to oxidative stress only in birds that did not benefit from a carotenoid-supplemented diet. This result therefore suggests that carotenoid availability can modulate the trade-off between reproduction and resistance to oxidative stress.

VLDL metabolism in rats is affected by the concentration and source of dietary protein.

The present study was designed to determine if changes in dietary protein level and source are related to changes in VLDL lipid concentrations and VLDL binding by hepatic membranes and isolated hepatocytes. Male Wistar rats were fed cholesterol-free diets containing 10, 20 or 30 g/100 g casein or highly purified soybean protein for 4 wk. Hepatic, plasma and VLDL lipids, VLDL apo B-100 and VLDL uptake by isolated hepatocytes and VLDL binding to hepatic membrane were determined. Increasing casein or soybean protein level (from 10 to 30 g/100 g) in the diet increased VLDL apo B-100, indicating an increase in the number of VLDL particles. VLDL uptake by isolated hepatocytes and VLDL binding to hepatic membrane increased when the protein level increased from 10 to 20 g/100 g in the diet and decreased with 30 g/100 g protein, regardless of protein type. The dietary protein source did not affect plasma total cholesterol concentrations at any protein level. Feeding 20 g/100 g soybean protein compared with casein lowered plasma triglyceride concentrations and VLDL number as measured by decreased VLDL-protein, -phospholipid, -triglyceride, -cholesterol and -apo B-100. VLDL uptake by isolated hepatocytes and VLDL binding to hepatic membrane were higher in rats fed soybean protein than those fed casein. The higher VLDL uptake could be responsible for the hypotriglyceridemia in rats fed soybean protein.