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International audience; Cognitive abilities were studied in rainbow trout, the first continental fish production in Europe. Increasing public concern for the welfare of farmed-fish species highlighted the need for better knowledge of the cognitive status of fish. We trained and tested 15 rainbow trout with an operant conditioning device composed of self-feeders positioned in front of visual stimuli displayed on a screen. The device was coupled with a two-alternative forced-choice (2-AFC) paradigm to test whether rainbow trout can discriminate 2-D photographs of conspecifics (S+) from different visual stimuli (S-). The S- were applied in four stages, the last three stages representing increasing discrimination difficulty: (1) blue shapes; (2) black shape (star); (3) photograph of an object (among a pool of 60); (4) photograph of another fish species (among a pool of 60). Nine fish (out of 15) correctly managed to activate the conditioning device after 30–150 trials. The rainbow trout were able to discriminate images of conspecifics from an abstract shape (five individuals out of five) or objects (four out of five) but not from other fish species. Their ability to learn the category "fish shape" rather than distinguishing between conspecifics and heterospecifics is discussed. The successful visual discrimination task using this complex operant conditioning device is particularly remarkable and novel for this farmed-fish species, and could be exploited to develop cognitive enrichments in future farming systems. This device can also be added to the existing repertoire of testing devices suitable for investigating cognitive abilities in fish.

International audience; For many fish species, environmental colour may act either as a source of stress or as a stress-buffer, alleviating behavioural and physiological responses after a stressful situation. While much is known on the effects of environmental colour on fish stress parameters, knowledge on the effects of stress on fish colour preferences is still lacking. In order to test the effects of stress on colour preference in fish, in this work, we exposed rainbow trout embryos (Oncorhynchus mykiss) to stressful conditions (air exposure, pheromone alarm cue or control, with minimal stress) from 19 to 44 days post fertilization (dpf). They were then raised up to 56 dpf in bright, dark, green or blue environments. After that, fry were individually tested for colour preference in a three-chambered arena where they could choose between green and blue areas. The time spent in the blue and in the green chamber was compared between experimental groups. Rainbow trout fry exposed to minimal stress (control) or to biotic stress (pheromone alarm) showed increased time in the blue environment, with little effect of ambient colour where they were raised. However, fish that experienced air exposure stress showed a lack of colour preference irrespective of the colour they were raised in afterwards. These results imply that early life stress affects colour preference in rainbow trout, suggesting that abiotic stressors, such as air exposure, may affect colour perception or behavioural plasticity in young fish. If the results presented herein are corroborated by future studies in fish at different life stages, beyond the embryonic phase, colour preference tests may be used as an additional and potential welfare indicator to estimate, in a retrospective manner, which stressors were faced by the individuals during early stages. By knowing whether or not their fish were exposed to certain stressful conditions may allow farmers to better adapt fish rearing conditions and to implement strategies that alleviate any long-term impacts that may exist, and, therefore, improve fish welfare.

Background Voice disorders are frequent after thyroidectomy. We report the long-term voice quality outcomes after thyroidectomy using the voice handicap index self-questionnaire. Methods Eight hundred patients who underwent total thyroidectomy between 2014 and 2017 in 7 French hospitals were prospectively included. All patients filled in voice handicap index questionnaires, preoperatively and 2 and 6 months after surgery. Results Median (range) voice handicap index scores were significantly increased at month 2 (4 [0; 108]) compared to preoperative values (2 [0; 76]) and were unchanged at month 6 (2 [2; 92]). Clinically significant voice impairment (voice handicap index score difference ≥18 points) was reported in 19.7% at month 2 and 13% at month 6. Thirty-seven (4.6%) had postoperative vocal cord palsy. In patients with vocal cord palsy compared to those without, median voice handicap index scores were increased at month 2 (14 [0; 107] vs 4 [0; 108]; P = .0039), but not at month 6 (5 [0; 92] vs 2 [0; 87]; P = .0702). Clinically significant impairment was reported in 38% vs 19% at month 2 (P = .010), and in 19% vs 13% at month 6 (P = .310). Thyroid weight, postoperative hypocalcemia, vocal cord palsy, and absence of intraoperative neuromonitoring utilization were associated with an increased risk of clinically significant self-perceived voice impairment at month 2. Conclusion Thyroidectomy impairs patients’ voice quality perception in patients with and without vocal cord palsy.

International audience; In trout aquaculture, tight control of water quality is crucial, especially for young life-history stages. This study examined whether chronic exposure to moderate hypoxia during the fry stage affects the rainbow trout’s behavior during later development. One month after yolk-sac resorption, young trout were exposed for 25 days to hypoxia, obtained by decreasing water flow and bubbling nitrogen gas into the tank (Hypoxia group, H: mean O2: 4.85 mg/L; min: 3.83, max: 6.87 mg/L). A control group was maintained in optimal conditions (C: mean O2: 10.41 mg/L; min: 10.12, max: 10.69 mg/L). At 4 days post-hypoxia, basal (resting) whole body cortisol levels were significantly higher in the H group (166.84 ± 20.67 ng/g) as compared to the C group (103.71 ± 8.78 ng/g), but no post-stress differences were evident (values ∼ 175 ng/g). Long-term effects of hypoxia on various behavioural traits were analysed between 3 and 4 months after the return to normoxia and compared to the C group. The exposure of fry to chronic hypoxia did not impact the fish’s behavioural repertoire (activity, stereotypic behaviour, aggression) in their home tanks after re-acclimation to normoxia. Moreover, basal and post-stress plasma cortisol levels, fear-related behaviours (novel-tank test), and risk-taking behaviours (emergence test) did not differ between the C and H groups. However, this early challenge resulted in an enhanced post-hypoxic growth rate in these fish. Our results show that early exposure to moderate hypoxia does not induce any behavioural changes in rainbow trout after several months of return to normoxia.

International audience; OBJECTIVE: Bariatric surgery appears as the most efficient therapeutic alternative in morbidly obese patients. In addition to its efficiency to decrease body weight, it also improves metabolic complications associated to morbid obesity, including dyslipidemia. Although the cholesterol-lowering effect varies with the bariatric procedures, the underlying molecular mechanisms remain poorly defined. This study aims to assess the consequence of both restrictive (sleeve gastrectomy; SG) and malabsorptive (Roux-en-Y gastric bypass; RYGB) procedures on cholesterol metabolism in mice. SUBJECTS: Ten-week-old C57BL6/J males were fed with a high-fat diet for 8-14 weeks before sleeve or RYGB surgery. RESULTS: SG has a modest and transient effect on plasma cholesterol levels, linked to a reduction in food intake. In contrast, modified RYGB led to a sustained ≈35% reduction in plasma cholesterol concentrations with a drastic increase in fecal cholesterol output. Mechanistically, RYGB exerts a synergystic effect on cholesterol metabolism by inducing the trans-intestinal cholesterol efflux and reducing the intestinal cholesterol absorption. CONCLUSIONS: In mice, RYGB, but not sleeve, strongly favors plasma cholesterol elimination by concomitantly increasing trans-intestinal cholesterol excretion and by decreasing intestinal cholesterol absorption. Our models open new perspective for deciphering the hypocholesterolemic effects of bariatric procedures.

International audience; Obesity is a major public health issue, with a prevalence of 4 to 28% for men and 6.2 to 36.5% for women in Europe (from 2003 to 2008). Morbid obesity is frequently associated with metabolic complications, such as type 2 diabetes, hypertension, and dyslipidemia, reducing life expectancy and quality. In the absence of any effective noninvasive treatments, bariatric surgery is a valuable therapeutic option for patients with morbid obesity (body mass index (BMI) \textgreater40 kg/m(2)), leading to long-term, sustained weight loss and improvements in metabolic complications. However, the underlying cellular and molecular mechanisms sustaining the beneficial effects of bariatric surgery are not yet fully understood. Due to the numerous genetically-modified strains available, the mouse model is the most convenient animal model to explore the molecular mechanisms behind the pleiotropic beneficial effects of bariatric surgeries. Here, we detailed the optimized healthcare methods and surgical protocols in mice for the two most widely-used bariatric surgeries: the sleeve gastrectomy and the modified Roux-en-Y gastric bypass. Deciphering the molecular mechanisms underlying the therapeutic effects of bariatric surgeries offers the promise of identifying new therapeutics targets.