PubMed Health⌕ Search

Biomedical subjects

T Gidenne

Publications and source records attributed to T Gidenne.

14 recordsLinked to original sources
PubMed1996

Consequences of reduced fibre intake on digestion, rate of passage and caecal microbial activity in the young rabbit.

The present work was undertaken to study in vivo fibre degradation, rate of passage and caecal fermentation activity (CFA) in the young rabbit (7 weeks old) receiving ad lib. a control (C) or low-fibre (LF) diet (400 and 220 g neutral-detergent fibre (NDF)/kg respectively). As a consequence of the 50% reduction in the dietary fibre level, the voluntary food intake of the rabbits decreased by 25%, and the daily fibre intake was reduced by 60% (26.7 and 10.8 g NDF/d for groups C and LF, respectively). In spite of a longer mean retention time of the fibre particles, the quantity of fibre digested daily was significantly lower (P < 0.01) for the LF than for the C group (4.0 and 7.8 g NDF/d respectively). The circadian distribution of the faecal excretion (as a percentage of the total DM output) did not differ between diets (P = 0.52) and no interaction was found (P = 0.96) between diet and time of excretion. Also, variables describing the CFA showed no interactions between diet (C or LF) and time of sampling (during caecotrophy or during hard faeces excretion). Our results indicated no direct relationship between the quantity of fibre digested and the total short-chain fatty acid concentration in the caecum, but the fermentation pattern indicated lower proportions of acetate for the LF diet. Higher levels of diaminopimelic acid (DAPA) and ATP were found for the LF diet associated with an improved dietary fibre digestibility, suggesting a higher microbial activity. However, this effect was balanced by a lower caecal digesta turnover rate and the microbial biomass output estimated through the faecal DAPA output did not vary significantly.

Animals↗
PubMed1995

Relationships between microflora and caecal fermentation in rabbits before and after weaning.

Some microbiological and biochemical parameters of caecal content were studied in 15- to 49-d-old rabbits that were slaughtered sequentially. The ammonia level did not differ before weaning (11.5 mmol/L on average) (P = 0.41) or after weaning (7.4 mmol/L on average) (P = 0.19) but decreased by 40% (P < 0.001) between days 29 and 32. The level of pH decreased linearly (P < 0.001) throughout the period studied. The Escherichia coli counts decreased up to weaning (P < 0.001) and was then not significantly affected by age (P = 0.12). The total volatile fatty acid (VFA) concentration increased between days 15 (8.2 mmol/L) and 25 (33.9 mmol/L) (P < 0.05) and then levelled off below 40 mmol/L. Molar proportions in propionate and in branched-chain fatty acid (BCFA) and valeric acid were high at day 15 but decreased when the animals began to eat solid feed. The C3/C4 ratio reversed at weaning (3.8 on day 15 and 0.5 on day 49) whereas the acetic acid proportion was not affected by age (P = 0.19). High counts of anaerobic microflora were found between 15 and 22 d of age (10(11) bacteria/g of caecal content, on average) and did not change significantly according to the age (at about 10(10) bacteria/g), from day 29 until the end of the experiment (P = 0.29). Amylolytic flora had a similar evolution at a slightly lower level. In contrast, under our breeding conditions cellulolytic microflora slowly colonized the caecum and remained at a low level. The discriminant analysis revealed relationships between ages, intestinal microflora and fermentation parameter; the colibacilli flora was associated with mother-fed animals and amylolytic flora which was linked to BCFA and valeric acid, while the cellulolytic flora was associated with animals older than 4 weeks and linked to the production of C2, C3, C4 and ammonia.

Aging↗
PubMed1995

In vivo study of circadian variations of the cecal fermentation pattern in postweaned and adult rabbits.

Two groups of cecal cannulated rabbits (postweaned and adult, 6 and 16 wk of age, respectively) were used to compare the circadian variations of the fermentation pattern. Rabbits were kept in metabolism cages under a 12:12 light-dark schedule (0700 to 1900). For each rabbit, a total of 12 samples of cecal material were collected (every 12 h) for six consecutive days to cover a 24-h cycle; feed ingestion and hard feces elimination were recorded. For postweaned and adult rabbits, the period of cecotrophy practice was mainly 0400 to 1200, and also 2200 to 2400 for the former and 0800 to 1400 for the later. Compared with those of adult rabbits, the cecal contents of the postweaned rabbits were characterized by a lower DM level (17.6 vs 20.3%; P < .001), a lower VFA level (65.4 vs 86.1 mM; P < .001), and a higher ammonia N level (7.6 vs 6.1%; P = .02) related to the presence of a double period of cecotrophy (only one in the adult rabbits), and corresponding to the postweaning adaptation of the cecal microflora to a dry feed. A lower butyrate molar proportion was found in postweaned than in adult rabbits (10.5 vs 13.6%; P = .004), whereas molar proportion of acetate and propionate remained similar regardless of the age of the rabbit. In the postweaned rabbits, changes in fermentation pattern were related to circadian rhythm of the cecotrophy practice. During this period, the levels of total VFA, acetate, and butyrate progressively decreased; the minimum was reached at 1200 (e.g., 53.8 44.6, and 4.4 mM, respectively); the corresponding propionate:butyrate ratio was 1.0.

Acetates↗
PubMed1994

[Effect of dietary fiber content reduction on digestive transit in the rabbit. Comparison and validation of models fitted to fecal marker excretion kinetics].

The rate of passage (RP) in several digestive compartments was studied in 4 adult female rabbits cannulated at ileum, and receiving ad libitum 3 diets with decreasing fibre content (40, 30 and 22% NDF). The RP values in the whole digestive tract and between ileum and rectum were simultaneously measured by following the fecal kinetics of 2 markers (169Yb and 141Ce adsorbed on the NDF fraction of the diets) given as single doses. The mean retention time (MRT) in the whole tract provided by modelling methods (models: Grovum and Williams or Ellis) were similar to those obtained by reference method (numeric integration). MRT values in the caecum and the stomach were provided by models and were in good agreement with those deduced from reference measurements. Compared with the Ellis model, the Grovum and Williams model estimated more precisely the RP in tubular compartments (ie small intestine and distal colon); but the increasing part of the kinetics was better fitted using the Ellis model, particularly for low-fibre diets. The decrease in fibre intake (-50%) led to a 12 h increase (+72%) of the whole tract MRT, originating mainly from a 2-fold increase of ileo-rectal MRT. The MRT in the stomach decreased from 3 to 1 h, whereas the RP in the small intestine increased. Therefore, the oro-ileal MRT (mean 5 h) was not affected. A low dietary fibre induces a longer cecal MRT of large particles, without significant change for fine particles.

Animals↗
PubMed1992

Effect of fibre level, particle size and adaptation period on digestibility and rate of passage as measured at the ileum and in the faeces in the adult rabbit.

The use of specific methods other than gravimetric ones to analyse fibre permitted a more precise study of the degradation of cell wall (CW) in the digestive tract. Digesta flow and rate of passage measurements have not been assessed previously in rabbits to investigate fibre digestion and fibre effects simultaneously in the proximal and in the distal segments of the tract. The effect of the level of dietary fibre on ileal and overall digestibility and rate of passage were studied by comparing semi-purified diets containing only one source of CW (dehydrated lucerne (Medicago sativa) meal) given to adult female rabbits. The effect of fibre particle size and adaptation period were also investigated. Measurements of fibre composition using both colorimetric and gas-liquid chromatographic techniques, showed that large amounts of (CW) were degraded in the caecocolic segments. Increasing dietary fibre level reduced the rate of passage but fibre degradation was increased, at the same time a lower digestive efficiency for energy in the small intestine was found. A small quantity of CW was apparently degraded before the caecum, assuming that the water-soluble fraction of CW was essentially implicated. Grinding lucerne meal through a 1 mm instead of a 3 mm screen did not improve CW digestibility in spite of a longer rate of passage in the caeco-colic segments. Adaptation to a high-fibre diet resulted in an higher digestive volume for colon and caecum, related to an improved degradation of CW. Furthermore, digestive efficiency in the small intestine appeared higher for rabbits adapted to a high-fibre diet than that for rabbits initially fed on a low-fibre diet.

Adaptation, Physiological↗
PubMed1992

[In vivo study of cecal fermentation activity in the rabbit. Completion and validation of a new technique for cecal cannulation].

A new technique for caecal cannulation in adult rabbit was validated in order to perform in vivo studies of caecal fermentation under a physiological status. The cannulation did not modify the digestibility of the diet, and it was possible to collect digesta (10 g fresh matter) after a few minutes without stress for animals only 10 days post-surgery. Volatile fatty acid (VFA) (60 mM/l) and ammonia (11 mM/l) concentration of caecal digesta collected in vivo was not different from that obtained from slaughtered rabbits. VFA measurements were reproducible (CV = 6.8%) and were not dependent on the daily collection frequency (1-5/day). Caecal VFA level in the starved rabbit was very low (23 mM/l) while the butyrate/propionate rate was the inverse (C4/C3 = 0.6). Five h after feeding, the in vivo VFA level reached 96 mM/l and the butyrate proportion (12%) over-reached those of propionate (3.5%). The caecal fermentations of a 7-week-old rabbit differed from those of an adult by a higher VFA level and by a greater post-feeding variation in the fermentation pattern.

Aging↗
PubMed1989

Flow and passage rate studies at the ileal level in the rabbit.

Six female rabbits fitted with a simple glass cannula in terminal ileum and a further 6 non-cannulated rabbits were used to perform digesta flow and transit measurements. The animals received ad libitum a diet based mainly on lucerne meal. Flow and transit measurements were carried out using two particulate markers: ytterbium (Yb) fixed on lucerne meal cell-walls by soaking, and chromium (Cr) fixed by mordancing. Both markers were incorporated in the same diet before pelleting. The digestibility coefficient or total mean retention time (MRTt) in the whole tract was not affected by cannulation. MRT values between cecum and rectum could be obtained in cannulated rabbits: 9.6 h. The MRTt values estimated with Yb were higher than those obtained with Cr because the size of particles labelled with Cr was probably greater and thus the particles were excreted more rapidly in hard feces. Flow measurements were not affected by the choice of marker, confirming indirectly the validity of ileal digesta samples. These first ileal flow measures obtained on cannulated rabbits indicate that about half (49%) of the digestible organic matter and two-thirds of the digestible crude protein apparently disappeared before the cecum. Cell-walls (CW), determined as NDF fraction, were totally recovered at the terminal ileum, although hemicellulose (NDF-ADF) digestion could occur in both the small intestine and the cecocolic parts. These results are discussed in relation to the specificity of the Van Soest method for digesta cell-wall analysis.

Animals↗
PubMed1989

[Marker transfer between food particles during digestive transit in the rabbit. Estimation method based on fecal granulometry].

Five adult rabbits (New Zealand White x Californian) were fed ad libitum for 10 days a pelleted feed compound containing dehydrated lucerne whose particles (0.05-0.5 mm in size) were marked with a rare earth, i.e. ytterbium (Yb). In order to estimate the proportion of marker liable to leave its initial site of binding, we measured the amount of ytterbium present on faeces particles larger than 0.5 mm. The total amount of faeces was collected during the following 3 days. The faeces screening technique used in this study was adapted from that applied to feed. However, the repeatability was low for the large particles (greater than 1 mm), whose number was small. Half of the digesta particles (52%) exhibited a smaller size than 0.05 mm. The proportion of large particles (greater than 1 mm) in the faeces was low (1.5%) while that of the other particle classes ranged from 20-33.5%. After pelleting, more than 40% Yb initially bound to lucerne particles measuring 0.5 to 0.05 mm, was present on fine particles (less than 0.05 mm). Accordingly, only minima and maxima amounts of Yb having migrated on large particles (greater than 0.5 mm) could be measured, i.e. 2.5 and 8.9%, respectively of the ingested Yb. Taking also into account a migration towards small particles, about 10% Yb was liable to leave its initial site during its passage through the digestive tract of the rabbit.

Animals↗
PubMed1987

[Effect of the addition of a fiber-rich concentrate to a hay-based diet, offered at two levels of feeding in the adult rabbit. 2. Measurements of digestibility].

The effect of adding a fibre-rich concentrate (wheat bran or beet pulp) to a hay-based diet (cook's foot-lucerne: 50/50) on the apparent digestibility of diets was measured in three groups of 8 adult doe rabbits (New-Zealand White X Californian). Diet composition was as follows: 90% hay only (diet F), hay + bran (diet FS) or hay + pulp (diet FP). Two levels of feeding were tested: ad libitum and 2/3 of ad libitum intake. Addition of wheat bran and especially of beet pulp led to a significant increase in the apparent digestibility of the whole diet. Our results confirm the high digestibility of cell-wall constituents of beet pulp: the apparent digestibility coefficient of hemicellulose in diet FP reached 60% (versus 23% for diet F) and that of cellulose 45% (21% for diet F). Wheat bran supplied digestible hemicellulose (ADC = 48% for diet FS) while the apparent digestibility of bran cellulose was not higher than that of hay (ADC = 22%). This digestive interaction between raw material was accompanied by an interaction with the digestive transit. The less digestible diet (diet F) exhibited the shortest mean residence time (MRT). However, diet FS exhibited the longest residence time whereas it was less digestible than diet FP. These results suggest that, in the rabbit, wheat bran is a transit-regulator as already observed in other species. Measuring apparent digestibility between the 10th and the 16th day of the feed restriction was too early for our doe rabbits. Values measured were not significantly different from those obtained during ad libitum feeding, although the MRT of diets was longer during restricted feeding.

Animals↗
PubMed1987

[Effect of the addition of a fiber-rich concentrate to a hay-based diet, offered at 2 dietary levels to adult rabbits. 1. Mean retention time of digesta].

The influence of adding a fibre rich concentrate feed (wheat bran or beet pulp) to a hay-based diet (orchard grass-lucerne mixture; 50/50) upon the rate of passage of digesta of these two fractions (hay and concentrate) was measured in three groups of 8 adult doe rabbits (White New Zealand x California). The three diets composed of either 90% hay, or hay + bran or hay + pulp were offered at two levels of feeding, i.e. ad libitum and 2/3 ad libitum. The retention time of the two main fractions was measured by means of two tracers, i.e. ytterbium-169 bound to hay and cerium-141 to bran or pulp. Animals fed on the 90% hay diet excreted more than 90% of the tracer during the first 24 h. The mean retention time (MRT) of this diet was the shortest (on an average 14.8 h). The addition of pulp or bran increased the MRT of the diet by 2 and 4 h, respectively. Feed restriction led to a 5 to 7 h earlier period of caecotrophy with a subsequent lengthening of the MRT by 2 to 4 h according to groups. The two hay + "concentrate" diets gave almost the same 169Yb and 141Ce excretion curves. Thus, the mean retention time seems to be the same for digesta from hay and "concentrate" (non significant deviations).

Animal Feed↗
PubMed1985

[Postnatal development of the fatty acid composition of lipids of adipose and muscle tissue in rabbits on a low-fat diet].

The relative fatty acid profiles of perirenal adipose tissue and muscle tissue of the hind legs were studied in New Zealand rabbits 21 to 140 days old. The rabbits were fed a low-fat diet covering the essential fatty acid requirements and distributed either ad libitum or in rationed amounts. The whole of the fatty acids were established earlier in hind leg muscle tissue than in perirenal adipose tissue. In the latter, the growth allometry of fatty acids in relation to the carcass was already higher between 21 and 74 days (a = 1.39) and distinctly higher between 74 and 140 days (a = 2.68). In the muscle tissue, an isometric phase (a = 0.96) preceded a major allometric phase (a = 1.76). In young suckling rabbits, the fatty acid profile of perirenal lipids was influenced by that of the milk lipids. In the muscle tissue, the presence of a large proportion of phospholipids resulted in a higher percentage of stearic acid and polyunsaturated fatty acids of the (n-6) family (linoleic, dihomo-gamma-linolenic and arachidonic acids). After weaning, the proportion of saturated fatty acids (C greater than or equal to 14) in the perirenal adipose tissue remained constant. The endogenous production of monounsaturated fatty acids (higher allometry) caused a progressive dilution of polyunsaturated fatty acids (lower allometry). This dilution was slowed down when the diet was rationed. Changes in the fatty acid composition of muscle tissue were, in general, comparable to those of perirenal adipose tissue. The differences observed could be attributed to the more active participation of phospholipids in the total lipids of the muscle tissue. Stearic acid, abundant in the phospholipids, showed a lower allometry compared to total fatty acids. Its dilution was an expression of triglyceride dilution of the phospholipids during growth. The same was true of polyunsaturated fatty acids. Rationing had the reverse effect.

Adipose Tissue↗
PubMedDate not supplied

Caecal microflora and fermentation pattern in exclusively milk-fed young rabbits.

Thirty-two SPF New Zealand White rabbits of both sexes were used in this experiment. They were sequentially slaughtered at 22, 29, 35 and 42 days of age. The rabbits were only milked by their mother and by foster mothers (no access to solid food) throughout the experiment. They exhibited a caecal fermentation pattern that turned towards a proteolytic metabolic activity (high levels in NH3 and in branched-chain fatty acids and valeric acid: 17 mmol.L-1 and 1 mmol.L-1, on average, respectively). The absence of caecal cellulolytic microflora and the low concentration of the total volatile fatty acids (tVFA) could be explained by the lack of substrate that would have been brought by a solid feed. From day 29 onwards, the low tVFA (12.5 mmol.L-1) and high NH3 concentrations (16.5 mmol.L-1) explained the high pH value (6.8 on average). This could be considered as a pathological value in weaned rabbits, but in our case no clinical signs of diarrhoea were observed. The evolution of the colibacilli flora according to age was similar to that usually described and thus was not correlated with pH, tVFA or cellulolytic flora. The evolution of the colibacilli population (from 10(7) bact/g on day 22 to 10(3) on day 42) seemed dependent on ontogenic factors rather than on the composition of the caecal media (pH, etc.).

Aging↗
PubMedDate not supplied

Digestive capacity of the rabbit during the post-weaning period, according to the milk/solid feed intake pattern before weaning.

The milk/solid feed intake pattern and digestive capacity were compared in two groups of young rabbits reared between 16 and 32 days in litters of four (L4 group, n = 18 litters) or ten pups (L10, n = 20) in order to modulate milk availability. Compared to the L4 group, rabbits in the L10 group presented a lower milk intake (22.3 versus 28.8 g x day(-1)) and a higher solid feed intake (12.9 versus 8.0 g x day(-1)) between 16 and 32 days of age. Live weight and weight gain were significantly lower in the L10 (-15%) than in the L4 group from 22 until 42 days. No significant difference was observed among the two groups for post-weaning digestibility and for the intraluminal specific or total activities of amylase and maltase. The total intraluminal activity (pool of enzyme) of amylase and maltase doubled between weaning (32 days) and 42 days. At weaning, the specific activity of amylase was similar in the jejunal and ileal segments (8.5 AU x g(-1)). From 32 to 42 days, the specific amylase activity doubled in the jejunum, while it remained steady in the ileum. The intraluminal specific maltase activity did not significantly change between 32 and 42 days, while it was twice as high in the jejunum compared to the ileum (3.5 versus 1.8 micromoles hydrolysed maltose x g(-1), respectively).

Amylases↗