Feeding predictability as a cognitive enrichment protects brain function and physiological status in rainbow trout: a multidisciplinary approach to assess fish welfare.

Cognitive enrichment is a promising but understudied type of environmental enrichment that aims to stimulate the cognitive abilities of animals by providing them with more opportunities to interact with (namely, to predict events than can occur) and to control their environment. In a previous study, we highlighted that farmed rainbow trout can predict daily feedings after two weeks of conditioning, the highest conditioned response being elicited by the combination of both temporal and signalled predictability. In the present study, we tested the feeding predictability that elicited the highest conditioned response in rainbow trout (both temporal and signalled by bubbles, BUBBLE + TIME treatment) as a cognitive enrichment strategy to improve their welfare. We thus analysed the long-term effects of this feeding predictability condition as compared with an unpredictable feeding condition (RANDOM treatment) on the welfare of rainbow trout, including the markers in the modulation of brain function, through a multidisciplinary approach. To reveal the brain regulatory pathways and networks involved in the long-term effects of feeding predictability, we measured gene markers of cerebral activity and plasticity, neurotransmitter pathways and physiological status of fish (oxidative stress, inflammatory status, cell type and stress status). After almost three months under these predictability conditions of feeding, we found clear evidence of improved welfare in fish from BUBBLE + TIME treatment. Feeding predictability allowed for a food anticipatory activity and resulted in fewer aggressive behaviours, burst of accelerations, and jumps before mealtime. BUBBLE + TIME fish were also less active between meals, which is in line with the observed decreased expression of transcripts related to the dopaminergic system. BUBBLE + TIME fish tented to present fewer eroded dorsal fin and infections to the pathogen Flavobacterium psychrophilum. Decreased expression of most of the studied mRNA involved in oxidative stress and immune responses confirm these tendencies else suggesting a strong role of feeding predictability on fish health status and that RANDOM fish may have undergone chronic stress. Fish emotional reactivity while isolated in a novel-tank as measured by fear behaviour and plasma cortisol levels were similar between the two treatments, as well as fish weight and size. To conclude, signalled combined with temporal predictability of feeding appears to be a promising approach of cognitive enrichment to protect brain function via the physiological status of farmed rainbow trout in the long term.

Impacts of mercury contaminated mining waste on soil quality, crops, bivalves, and fish in the Naboc River area, Mindanao, Philippines.

Rice paddy fields in the Naboc area, near Monkayo on the island of Mindanao, Philippines, have been irrigated four times a year over the last decade using Naboc River water contaminated with mercury (Hg) by artisanal gold mining in the Diwalwal area. Silt containing up to at least 90 mg Hg/kg (d.w.) has been deposited in rice paddy fields during the 1990s and this has been repeatedly mixed into the rice root zone through ploughing. Hg in the rice paddy field soils averages 24 mg Hg/kg and generally exceeds the UK and Canadian soil quality thresholds for agricultural soils as well as the proposed Dutch Intervention value and the USEPA soil ingestion Soil Screening Level (SSL) for inorganic Hg. Much lower Hg concentrations (0.05-0.99 mg/kg) within the range expected for uncontaminated soils, characterise soils on which corn and bananas are cultivated, largely because these are not irrigated with Hg-contaminated water from the Naboc River. The estimated total weekly MeHg intake for a person living in the Naboc area related to the weekly consumption of 2.1 kg of rice grown on Hg-contaminated soils (15 microg MeHg) in conjunction with 1 kg of fish (220 microg MeHg) and 100 g of mussels (50 microg MeHg) from the Naboc River, would total 285 microg MeHg (equivalent to 4.75 microg/kg bw for a 60 kg adult), which is nearly three times the JECFA PTWI of 1.6 microg/kg bw. This will significantly contribute to the population mercury exposure and might explain why 38% of the local inhabitants were classified as Hg intoxicated during a mercury toxicity assessment [Drasch GS, Böse, O'Reilly S, Beinhoff C, Roider G, Maydl S. The Mt. Diwata study on the Philippines 1999-assessing mercury intoxication of the population by small scale gold mining. Sci Total Environ 2001; 267(1-3): 151-168.].

Sex-Specific Effects of Chronic Administration of Relaxin-3 on Food Intake, Body Weight and the Hypothalamic-Pituitary-Gonadal Axis in Rats.

The present study examined the effects of chronic central administration of relaxin-3 (RLN3) on food intake, body weight and fat mass in intact and sterilised male and female rats, as well as on hypothalamic-pituitary-gonadal (HPG) axis activity in intact male and female rats that received i.c.v. infusions of RLN3 (400 pmol/day) or vehicle during a 14-day period. The intact RLN3-injected rats displayed a higher body weight than the vehicle-treated groups, and this increase was statistically significantly stronger in female rats compared to male rats. In addition, feed efficiency and gonadal white adipose tissue weight were higher in female RLN3-injected rats. Chronic i.c.v. administration of RLN3 activated the HPG axis in intact male rats, whereas inhibition of the HPG axis was observed in intact female rats. RLN3 significantly increased the plasma levels of luteinising hormone and follicular-stimulating hormone in male rats but not in female rats. Conversely, hypothalamic expression of gonadotrophin-releasing hormone mRNA was decreased by RLN3 in female rats but not in male rats. In addition, the plasma levels of oestradiol were significantly decreased by RLN3 administration in female rats. Consequently, intact RLN3-injected female rats failed to display phasic inhibition of eating during oestrus. Sex-specific effects of RLN3 on food intake and body weight were also observed in ovariectomised female and orchidectomised male rats, suggesting that the sex-specific effects of RLN3 on energy metabolism are independent on the differential effects of RLN3 on HPG axis activity in male and female rats.

Differential effects of central administration of relaxin-3 on food intake and hypothalamic neuropeptides in male and female rats.

Relaxin-3 (RLN3) is an orexigenic neuropeptide that produces sex-specific effects on food intake by stronger stimulation of feeding in female compared with male rats. This study determined which hypothalamic nuclei and associated neuropeptides may be involved in the sex-specific orexigenic effects of RLN3. Relaxin-3 (800 pmol) or vehicle was injected into the lateral ventricle of female and male rats. Food and water intake were measured after the first injection, and rats were euthanized after the second injection to determine the mRNA expression of the hypothalamic neuropeptides. Food but not water intake showed sex-specific effects of RLN3. Stimulation of food intake by RLN3 was significantly higher in female than in male rats. No effect of RLN3 injection was found on c-fos mRNA expression in the arcuate, dorsomedial and ventromedial hypothalamic nuclei. Increased c-fos mRNA expression was observed in the paraventricular hypothalamic nucleus (PVN) in both sexes and in the lateral hypothalamic area (LHA) in female rats. Relaxin-3 injections led to a sex-nonspecific increase in the expression of oxytocin mRNA in the magnocellular PVN. Conversely, RLN3-induced expression of anorexigenic neuropeptide arginine vasopressin (AVP) was significantly higher in the parvocellular PVN in male compared with female rats. Finally, RLN3 administration significantly increased the expression of orexin (ORX) mRNA in the LHA in female but not in male rats. Stronger expression of anorexigenic AVP in the PVN in male rats and increased expression of ORX in the LHA in female rats may contribute to stronger orexigenic effects of RLN3 in female rats compared with male rats.

[Pulmonary embolism. Risk factors of venous thromboembolic disease]. / Embolie pulmonaire. Facteurs de risque de la maladie thrombo-embolique veineuse.

RISK FACTORS: Management of deep venous thromboembolism both in terms of diagnosis and therapeutic and prophylactic strategies has been greatly improved by advances in knowledge of the main acquired and intrinsic risk factors. RESISTANCE TO ACTIVATED PROTEIN C: This is by far the most frequent coagulation disorder predisposing to venous thromboembolism. Other intrinsic factors favoring thrombus formation (anti-thrombin II, protein C or protein S deficiencies) are much more uncommon. Laboratory tests in search for these anomalies are indicated essentially for patients who develop repeated episodes of venous thrombus formation. PROPHYLAXIS: Excepting specific cases, anticoagulant prophylaxis is not indicated in any of these anomalies beyond the usual treatment of a first episode. Among the risk factors for acquired deep vein thromboembolism, only surgery and certain obstetrical indications have been investigated sufficiently to define validated prophylaxis strategies. For medical risks, the benefit of anticoagulant prophylaxis has been demonstrated in certain disease states such as cancer, antiphospholipid syndrome and the acute phase of myocardial infarction although no widely accepted strategy has yet been established.

["Post traumatic" leptospirosis complicated by acute respiratory insufficiency]. / Leptospirose ictéro-hémorragique << post traumatique >> compliquée d'insuffisance respiratoire aiguë

INTRODUCTION: Leptospirosis is a rare cause of alveolar haemorrhage. The diagnosis is often delayed particularly when the mode of infection is atypical. These serious complications require prompt antibiotic treatment. CASE REPORT: A 21-year-old man was involved in a road accident and found lying unconscious in a roadside ditch containing stagnant water. Ten days later he presented with bilateral interstitial pneumonia and rapidly increasing hypoxaemia associated with cholestasis and liver cell necrosis. Broncho-alveolar lavage revealed alveolar haemorrhage. There was satisfactory resolution following antibiotic therapy. CONCLUSIONS: The diagnosis of leptospirosis was considered initially despite negative serology (Martin and Petit) and confirmed by sero-conversion 20 days after the onset of symptoms.

Protein intake, calcium balance and health consequences.

High-protein (HP) diets exert a hypercalciuric effect at constant levels of calcium intake, even though the effect may depend on the nature of the dietary protein. Lower urinary pH is also consistently observed for subjects consuming HP diets. The combination of these two effects was suspected to be associated with a dietary environment favorable for demineralization of the skeleton. However, increased calcium excretion due to HP diet does not seem to be linked to impaired calcium balance. In contrast, some data indicate that HP intakes induce an increase of intestinal calcium absorption. Moreover, no clinical data support the hypothesis of a detrimental effect of HP diet on bone health, except in a context of inadequate calcium supply. In addition, HP intake promotes bone growth and retards bone loss and low-protein diet is associated with higher risk of hip fractures. The increase of acid and calcium excretion due to HP diet is also accused of constituting a favorable environment for kidney stones and renal diseases. However, in healthy subjects, no damaging effect of HP diets on kidney has been found in either observational or interventional studies and it seems that HP diets might be deleterious only in patients with preexisting metabolic renal dysfunction. Thus, HP diet does not seem to lead to calcium bone loss, and the role of protein seems to be complex and probably dependent on other dietary factors and the presence of other nutrients in the diet.

Inhibition of food intake induced by acute stress in rats is due to satiation effects.

Acute mild stress induces an inhibition of food intake in rats. In most studies, the cumulative daily food intake is measured but this only provides a quantitative assessment of ingestive behavior. The present study was designed to analyze the reduction in food intake induced by acute stress and to understand which behavioral and central mechanisms are responsible for it. Two different stressors, restraint stress (RS) and forced swimming stress (FSS), were applied acutely to male Wistar rats. We first measured corticosterone and ACTH in plasma samples collected immediately after acute RS and FSS in order to validate our stress models. We measured food intake after RS and FSS and determined meal patterns and behavioral satiety sequences. The expressions of CRF, NPY and POMC in the hypothalamus were also determined immediately after acute RS and FSS. The rise in corticosterone and ACTH levels after both acute RS and FSS validated our models. Furthermore, we showed that acute stress induced a reduction in cumulative food intake which lasted the whole day for RS but only for the first hour after FSS. For both stressors, this stress-induced food intake inhibition was explained by a decrease in meal size and duration, but there was no difference in ingestion speed. The behavioral satiety sequence was preserved after RS and FSS but grooming was markedly increased, which thus competed with, and could reduce, other behaviors, including eating. Lastly, we showed that RS induced an increase in hypothalamic POMC expression. These results suggest that acute stress may affect ingestive behavior by increasing satiation and to some extent by enhancing grooming, and this may be due to stimulation of the hypothalamic POMC neurons.

Asymmetric distribution of phospholipids in spectrin-poor erythrocyte vesicles.

We have investigated by electron spin resonance, at 37 degrees C, the outside-inside passage and the equilibrium distribution of spin-labeled phospholipids, respectively, in ATP-containing ghosts, in heat-treated erythrocytes, and in heat-induced vesicles. The heat-treated vesicles were spectrin depleted to approximately 25% of the original content and had lost almost 100% of the other cytoskeletal proteins. Yet the vesicles, as long as they contained ATP, were capable of translocating the aminophospholipids with the same efficiency as the heat-treated erythrocytes, and almost with the same efficiency as ATP-containing ghosts. In the vesicles, sphingomyelin and phosphatidylcholine analogues underwent a very slow transverse diffusion as in native cells. We conclude that spectrin and other cytoskeleton proteins are not major factors for the establishment and maintenance of phospholipid asymmetry in human erythrocytes, which may be chiefly due to the aminophospholipid translocase activity.