PubMed Health⌕ Search

Biomedical subjects

F Lebas

Publications and source records attributed to F Lebas.

14 recordsLinked to original sources
PubMed1992

[In vitro simulation of rabbit cecal fermentation in a semi- continuous flow fermentor. II. Effect of inoculum type].

Two Rusitec fermentors were operated under identical conditions. One was seeded with an inoculum of rabbit caecal contents, and the other with bovine rumen contents. The fermentation substrate was rabbit feed that had been digested with amylase and pepsin. The substrate constituents (organic matter, OM and NDF) were lost in 48 h at a significantly higher rate in the presence of rumen inoculum (OM: +10%, NDF: +15%). The pHs of the 2 fermentors were similar at pH 6.6. The fermentors produced similar amounts of protein nitrogen per 24 h, after 6 d of adaptation. Volatile fatty acid production was slightly higher in the presence of rumen inoculum. The fermentor inoculated with rumen contents produced a higher percentage of propionic acid (25%) than of butyric acid (7%), while fermentation with rabbit caecal contents gave the opposite ratio (C3/C4 = 0.81). Consequently, only the rabbit caecal inoculum provided the fermentation profile characteristic of the species.

Amylases↗
PubMed1992

[In vitro simulation of rabbit cecal fermentation in a semi- continuous flow fermentor. I. Role of food substrate pretreatment].

A Rusitec semi-continuous flow fermentor was used to study the influence of enzyme pretreatment of food substrates on the fermentation profile over a 2-week period following inoculation with rabbit caecal contents. Three types of substrate were examined: 1) homogenized commercial rabbit feed; 2) the solid remains of this feed after digestion with alpha-amylase for 24 h; and 3) substrate 2 digested for 4 h with pepsin (double enzyme treatment). One of a pair of nylon pouches containing 15 g substrate was replaced each day, thus producing a uniform 48-h fermentation. Fermentation of the untreated feed (1) for 5-6 days produced a fermentation profile quite different from that obtained in vivo in the rabbit caecum: propionic acid accounted for over 35% of total volatile fatty acid (VFA), and butyric acid for about 15%. Amylase digestion (2) gave a stable ferment profile closer to the in vivo profile, except that propionic and butyric acids were similar at 15% of total VFA. Digestion with both amylase and pepsin (3) produced a stable fermentation profile very close to the in vivo profile: C2 > 60%, C3 < 11% and 17% < C4 < 21%. The rate at which membrane constituents (acid detergent fibre, ADF) were lost in 48 h was similar to the digestibility coefficient measured in vivo by others for the same basic feed. Lastly, there was a high percentage (about 5%) of volatile C5 fatty acids; this could be due to the discontinuous fermentor input of one pouch per 24 h. Thus, feed pretreated with both amylase and pepsin simulates, in vitro, rabbit caecal fermentation in a semi-continuous Rusitec type fermentor.

Animal Feed↗
PubMed1986

[Experimental study of diarrhea induced by a strain of Escherichia coli (serogroup O-103) in growing rabbits].

The experimental infection by mouth of weaned, 6 week old rabbits was performed with Escherichia coli strain O-103/10 without any adjuvant. The quantities of E. coli for the 3 experimental treatments were - none (control) - 10(4) or 10(7) per animal. The 142 rabbits were divided into 2 groups, each including the 3 treatments: A - observation of weight and eventual diarrhea during 25 days after infection; B - killing during the same period of some healthy and diarrheic animals every 2 or 3 days, for physiological, bacteriological, and histological observations. In the A group, mortality after 25 days was 0/24 in the control, 12 and 15/24 for 10(4) and 10(7) treatments respectively, but it was observed earlier for the 10(7) one. Diarrhea has been observed for 90% of infected and 20% of control rabbits, at first on day 7, 12 and 20 post-infection for the 10(7), 10(4) and control treatments respectively. The mean duration of diarrhea was 4 days in infected and only 2 in control rabbits. Always, diarrhea and weight lost were observed before death. Although the slowing down of growth rate during the experimental period, at the end, mean live weight was quite the same for animals surviving in the 3 treatments. Necropsy of killed rabbits of the B group, revealed hemorrhagic damages mainly on cecal and colonic wall, associated with high counts for E. coli (10(7) to 8 X 10(9] in the cecal content. In rabbits with highest counts (9/15), E. coli was also observed in blood. In diarrheic rabbits cecal pH was higher (6.61 vs 5.82) and cecal VFA concentration lower (53 vs 98 mM/l) than in healthy ones; but the proportions of acetic, propionic and butyric acids were not significantly affected. At constant VFA concentration in the cecum, pH and E. coli counts were correlated (r = + 0.35). Histology revealed first, attachment of bacteria to the apex of villi cells, and furthermore destruction of the epithelium with hemorrhages and necrosis. Thus the strain O-103/10 of E. coli is confirmed to be pathogenic and will provide a good experimental model for studies of diarrhea due to E. coli.

Animals↗
PubMed1980

[Water and food ingestion in the young rabbit given food deficient in methionine or lysine and drinking by free choice a solution of that amino acid or pure water].

In a first trial, 21 five-week old rabbits housed in individual cages were divided into 3 experimental lots. All of them received the same lysine-deficient pelleted diet but lot 1 drank pure water only, lot 2 had a free choice between a solution of l-lysine (1.6 g/l) or pure water, and lot 3 drank l-lysine only. The trial lasted 24 days. The growth of lot 1 rabbits was significantly lower than that of lot 3 rabbits. The performance of lot 2 animals was intermediate but quite similar to that of lot 3. The lot 2 animals drank significantly more of the lysine solution than pure water (56 vs 44 p. 100). In a second trial, 60 five-week old rabbits housed 5 to a cage were divided into 4 lots. Lot 1 received a sulphur amino acid (AAS)-deficient diet + pure water, lot 2 a balanced diet + pure water, lot 3 the deficient diet + pure water and a solution of dl-methionine (1 g/l), and lot 4 the deficient diet + pure water + another dl-methionine solution (3 g/l). The trial lasted 19 days. Lot 2 showed improved growth due to the intake of the better AAS balanced diet. Lot 3 and 4 rabbits had intermediate growth which approached that of lot 2 animals as the methionine concentration in the solution increased. In both cases, the rabbits preferred the methionine solution to the pure water: 77 p. 100 in lot 3 (1 g/l) and 60 p. 100 in lot 4 (3 g/l). In conclusion, when the diet was deficient in AAS or in lysine and there was a free choice between either pure water or a solution of the deficient amino acid, the rabbits preferred the solution.

Animals↗
PubMed1976

[Gram-negative bacterial lung diseases in an internal medicine department].

In a department of internal medicine in Paris, the pneumonopathies with Gram negative "wild" bacilli represent about the third of recognized bacterial pneumonopathies. If started before the results of bacterial tests are known, the treatment should always include a drug active on Gram negative bacteria. Together with KLASTERSKY (1972) we think that synergic associations including the use of Gentamicin are the most effective. Once the responsible germ isolated and its sensitivity to antibiotics determined, therapy can be modified accordingly. With an appropriate antibiotic and by treating an unfavourable background and the initial localization, prognosis is favourable in most cases. This contrasts with the heavy mortality of pulmonary infections with Gram negative bacilli pertaining to hospital.

Adult↗
PubMed1975

[Electron microscopic identification of thymidine-incorporating cells in a population with a low turnover rate. Application to deep lung cells].

Many cells difficult to identify by photon microscopy were identified by using serial thin and semithin epoxy section. This procedure made it possible to carry out significant statistical analysis on a restricted number of sections. When applied to the study of cell renewal in the deep lung, each cellular proliferation could be quantified.

Animals↗