Effect of pig faecal donor and of pig diet composition on in vitro fermentation of sugar beet pulp.

Two experiments were undertaken to investigate the influence of (1) pig bodyweight and (2) dietary fibre content of the diet on the in vitro gas production of sugar beet pulp fibre using faecal inoculum. In the first experiment, inocula prepared from young pigs (Y; 16–50 kg), growing pigs (G; 62–93 kg) and sows (S; 216–240 kg) were compared. Sugar beet pulp, hydrolysed in vitro with pepsin and then pancreatin, was used as the fermentation substrate. The cumulated gas productions over 144 h were modelled and the kinetics parameters compared. Lag times (Y: 4.6 h; G: 6.4 h; S: 9.2 h) and halftimes to asymptote (Y: 14.7 h; G: 15.9 h; S: 20.8 h) increased with pig bodyweight (P<0.001) and the fractional degradation rates of the substrate differed between the pig categories (Y: 0.110 h−1; G: 0.115 h−1; S: 0.100 h−1; P<0.001). The final gas productionwas not affected (P=0.10) by the inoculum source. In the second experiment hydrolysed sugar beet pulp was fermented with four inocula prepared from pigs fed diets differing in their total and soluble dietary fibre contents, i.e. low fibre diet rich in soluble fibre (LOW-S) or in insoluble fibre (LOW-I) or high fibre diet rich in soluble fibre (HIGHS) or in insoluble fibre (HIGH-I). The total and the soluble dietary fibres influenced the kinetics of gas production. The presence of soluble fibres decreased the lag times, whatever the total dietaryfibre content (2.7 h for LOW-S versus 3.5 h for LOW-I, 4.0 h for HIGH-S versus 4.4 h for HIGH-I; P<0.001). The half-times to asymptote were higher with the low fibre diets (P<0.001) and, for similar total dietary fibre contents, they were lower when the proportion of soluble fibres increased (LOW-S: 9.9 h; LOW-I: 11.4 h; HIGH-S: 8.9 h; HIGH-I: 10.1 h; P<0.001). The fractional degradation rates of the substrate were the highest with the fibre-rich diet containing a high proportion of soluble fibres (0.158 h−1; P<0.001). In conclusion, the bodyweight of the faeces donors and the dietary fibre composition of the pig diet influence the in vitro fermentation kinetics of hydrolysed sugar beet pulp, but not the final gas production

Enseignement des sciences et de la technologie fondé sur l’investigation au collège

Dans le cadre des nouveaux programmes mis en place au collège depuis la rentrée 2006, les prescriptions institutionnelles envisagent l’apprentissage des sciences et de la technologie par une démarche d’investigation considérée comme méthode d’enseignement privilégiée (B.O.E.N. Hors Série n°5 du 25 août 2005, p 6). Cette recherche vise à identifier quelle mise en œuvre a lieu effectivement dans les classes par les enseignants de sciences physiques et de technologie au collège. Il s’agit de regarder si le travail d'un groupe d'enseignants et de chercheurs permet de mettre en évidence les enjeux d'un enseignement fondé sur l'investigation, et les conditions favorisant sa mise en œuvre par les praticiens

Potential Use of Poly-N-Acetyl-β-(1,6)-Glucosamine as an Antigen for Diagnosis of Staphylococcal Orthopedic-Prosthesis-Related Infections▿

Staphylococcus aureus and coagulase-negative staphylococci are microorganisms most frequently isolated from orthopedic-implant-associated infections. Their capacity to maintain these infections is thought to be related to their ability to form adherent biofilms. Poly-N-acetyl-β-(1,6)-glucosamine (PNAG) is an important constituent of the extracellular biofilm matrix of staphylococci. In the present study, we explored the possibility of using PNAG as an antigen for detecting antibodies in the blood sera of patients with staphylococcal orthopedic-prosthesis-associated infections. First, we tested the presence of anti-PNAG antibodies in an animal model, in the blood sera of guinea pigs that developed an implant-associated infection caused by biofilm-forming, PNAG-producing strains of Staphylococcus epidermidis. Animals infected with S. epidermidis RP62A showed levels of anti-PNAG immunoglobulin G (IgG) significantly higher than those of the control group. The comparative study of healthy individuals and patients with staphylococcal prosthesis-related infections showed that (i) relatively high levels of anti-PNAG IgG were present in the blood sera of the healthy control group, (ii) the corresponding levels in the infected patients were slightly but not significantly higher, and (iii) only 1 of 10 patients had a level of anti-PNAG IgM significantly higher than that of the control group. In conclusion, the encouraging results obtained in the animal study could not be readily applied for the diagnosis of staphylococcal orthopedic-prosthesis-related infections in humans, and PNAG does not seem to be an appropriate antigen for this purpose. Further studies are necessary to determine whether the developed enzyme-linked immunosorbent assay method could serve as a complementary test in the individual follow-up treatment of such infections caused by PNAG-producing staphylococci

VERS UNE PRODUCTION D’OUTILS DE FORMATION EN SCIENCES ET TECHNOLOGIE POUR LE PREMIER DEGRE

Les travaux s'appuient en particulier sur les orientations actuelles en termes de prescriptions en lien avec la mise en œuvre d'un enseignement des sciences par investigation et s'appuient sur de nombreux travaux à ce sujet. Des séquences d'enseignement sont conçues en vue de créer des outils de formation où une attention particulière est portée à la notion de débat scientifique, qui fait partie des stratégies didactiques très étudiées dans la recherche en éducation scientifique

Long-Term Physiological Alterations and Recovery in a Mouse Model of Separation Associated with Time-Restricted Feeding: A Tool to Study Anorexia Nervosa Related Consequences

<div><p>Background</p><p>Anorexia nervosa is a primary psychiatric disorder, with non-negligible rates of mortality and morbidity. Some of the related alterations could participate in a vicious cycle limiting the recovery. Animal models mimicking various physiological alterations related to anorexia nervosa are necessary to provide better strategies of treatment.</p><p>Aim</p><p>To explore physiological alterations and recovery in a long-term mouse model mimicking numerous consequences of severe anorexia nervosa.</p><p>Methods</p><p>C57Bl/6 female mice were submitted to a separation-based anorexia protocol combining separation and time-restricted feeding for 10 weeks. Thereafter, mice were housed in standard conditions for 10 weeks. Body weight, food intake, body composition, plasma levels of leptin, adiponectin, IGF-1, blood levels of GH, reproductive function and glucose tolerance were followed. Gene expression of several markers of lipid and energy metabolism was assayed in adipose tissues.</p><p>Results</p><p>Mimicking what is observed in anorexia nervosa patients, and despite a food intake close to that of control mice, separation-based anorexia mice displayed marked alterations in body weight, fat mass, lean mass, bone mass acquisition, reproductive function, GH/IGF-1 axis, and leptinemia. mRNA levels of markers of lipogenesis, lipolysis, and the brown-like adipocyte lineage in subcutaneous adipose tissue were also changed. All these alterations were corrected during the recovery phase, except for the hypoleptinemia that persisted despite the full recovery of fat mass.</p><p>Conclusion</p><p>This study strongly supports the separation-based anorexia protocol as a valuable model of long-term negative energy balance state that closely mimics various symptoms observed in anorexia nervosa, including metabolic adaptations. Interestingly, during a recovery phase, mice showed a high capacity to normalize these parameters with the exception of plasma leptin levels. It will be interesting therefore to explore further the central and peripheral effects of the uncorrected hypoleptinemia during recovery from separation-based anorexia.</p></div

Alterations of reproduction.

<p>Ovary size of mice in standard conditions (CT), or separated and submitted to food access restriction (SBA) after 2 and 10 weeks of protocol, followed by 2 and 10 weeks of standard housing conditions. <i>A</i>: Ovary length measured on ovary slices. <i>B</i>: Ovary width measured on ovary slices. Data represent mean ± SEM; n = 6/group. *<i>p</i><0.05 and **<i>p</i><0.005 when compared with CT group at the same duration; ^‡<i>p</i><0.05 when compared with previous value of the same group.</p

Expression analysis in adipose tissues of genes involved in lipid metabolism.

<p>Relative mRNA levels of Glut4, FASn, ABHD5 and ATGL were determined by real-time PCR experiments, in subcutaneous (SCAT) and visceral adipose tissues (VAT) of control □ and SBA ▪ mice. PPIA and HPRT were used as housekeeping genes. All results are expressed as fold-change compared to one SCAT of the control group after 10 weeks. Analyses were done after 10 weeks of SBA protocol and 10 additional weeks of REC protocol. Data represent mean ± SEM; n = 5–10/group. *<i>p</i><0.05 and **<i>p</i><0.005 when compared to CT group at the same duration; ^‡<i>p</i><0.05 and ^{‡ ‡}<i>p</i><0.005 when compared to the previous value of the same group.</p

Intraperitoneal glucose tolerance test in mice in standard conditions (CT), or separated and submitted to time-restricted feeding (SBA) after 2 and 10 weeks of protocol, followed by 2 and 10 weeks of standard housing conditions.

<p>Data represent mean ± SEM; n = 6–10/group. *<i>p</i><0.05 and **<i>p</i><0.0001 significant differences between the two curves using Two-way ANOVA.</p

Leptin and adiponectin.

<p><i>A</i>: Plasma concentrations of leptin and adiponectin of mice in standard conditions, CT(□), or separated and submitted to food access restriction, SBA(▪) after 2 and 10 weeks of protocol, followed by 2 and 10 weeks of standard housing conditions. <i>B</i>: Relative leptin and adiponectin mRNA levels in SCAT and VAT vs HPRT and PPIA housekeeping genes. Data represent mean ± SEM; n = 6–10/group. *<i>p</i><0.05 and **<i>p</i><0.005 when compared to CT group at the same duration; ^‡<i>p</i><0.05 and ^‡‡<i>p</i><0.05 when compared to the previous value of the same group.</p