Impact of fibre deficiency and sanitary status on non-specific enteropathy of the growing rabbit
Impact of fibre deficiency and sanitary status on non-specific enteropathy of the growing rabbit
rry GIDENNE 1
0 Laboratoire de Pathologie du Lapin, Station de Pathologie Aviaire et de Parasitologie, INRA Tours , 37380 Nouzilly , France
1 Station de Recherches Cunicoles, INRA Toulouse , BP 27, 31326 Castanet-Tolosan , France
- The effects of a sharp reduction in dietary fibre level (19 to 9% ADF resp. for “S” and “D” diet) were studied on the health status and performances of two groups of rabbits with different sanitary statuses: conventional “C” (n = 224) and specified pathogen free 'SPF' (n = 72) from 28 to 70 days of age. Digestive pathology was monitored daily and individually along the whole fattening period (28-70 d old) to precisely quantify the impact of a fibre deficiency on rabbit health. Diarrhoea was the most common symptom of enteritis due to fibre deficiency (90% of cases). The major digestive lesions were dilatation of the caeco-colic segment (30%) and a watery intestinal and caecal digesta (60%). The digestive troubles had a similar expression with respect to sanitary status or diet effect. The mortality and the Health Risk index (HRi = mortality + morbidity rate) respectively reached 25 and 60% with the fibre deficient diet “D” (28-70 d period) compared to 9 and 41% for the standard diet “S” (P < 0.05). The digestive disturbances appeared mainly during the period 28-42 d for SPF rabbits, and later for the C rabbits (43-56 d). Morbidity, HRi and the duration of diarrhoea were respectively 7, 2 and 3 times higher for C rabbits as compared to the SPF rabbits. A synergetic effect of fibre deficiency and conventional sanitary status was observed on the incidence and intensity of digestive troubles. For individually caged rabbits, morbidity seemed to be mainly linked to the sanitary status of the animal (SPF or conventional), while the mortality level was enhanced by a fibre deficiency. The fibre supply thus seemed to prevent morbidity from evolving into mortality. In conclusion, non-specific enteropathy depends jointly on sanitary and nutritional status of the animals.
70 j d’âge), afin de quantifier avec précision l’impact de la déficience en fibre sur l’état sanitaire
du lapin. La diarrhée est le symptôme le plus fréquemment observé dans les entérites provoquées par
la réduction du taux de fibres (90 % des cas). Les lésions digestives sont essentiellement, une
dilatation du segment caeco-colique (30 % de cas) et une liquéfaction du contenu digestif intestinal et
caecal (60 % de cas). La mortalité et le Risque Sanitaire (HRi = mortalité + morbidité) atteignent
respectivement 25 et 60 % chez les lapins nourris avec le régime déficient en fibres « D » (période
28–70 j d’âge), contre 9 et 41 % chez ceux nourris avec le régime témoin « S » (P < 0,05).
L’intensité des entérites atteint son maximum entre 28 et 42 j d’âge pour les EOPS, alors que chez les lapins
C, elle est plus tardive (43 à 56 j). Chez les lapins C, la morbidité, le risque sanitaire, et la durée de
la diarrhée sont plus importants que chez les EOPS d’environ 7, 2 et 3 fois. Un effet de synergie
négatif, de la déficience en fibres combinée à un statut sanitaire conventionnel, est observé sur
l’intensité et la fréquence des diarrhées. Pour les animaux logés individuellement, la morbidité
semble essentiellement liée à leur statut sanitaire (EOPS ou conventionnels), alors que le taux de
mortalité est accru par la déficience en fibres alimentaires. L’apport de fibre semble agir en tant que
facteur de prévention de l’évolution de la morbidité en mortalité. En conclusion, les diarrhées
nonspécifiques dépendent conjointement du statut sanitaire et nutritionnel des animaux.
lapin / déficience en fibres / statut sanitaire / pathologie digestive / nutrition
Digestive pathology is the most
important problem encountered in rabbit breeding
], and occurs mainly in young rabbits
after weaning (4–8 weeks of age).
Enteropathology is mainly responsible for an
increase in mortality rate after weaning that
reaches 14% in France [
] but may
frequently exceed 20% in cases of specific
epidemy. Digestive disorders are also
responsible for a significant morbidity (depression
of growth and poor feed conversion).
Although the losses in performance and
efficiency due to transient diarrhoea are costly,
they are difficult to evaluate in field
conditions. Diarrhoea is the main clinical
symptom of enteropathy and could have several
origins. It is possible to distinguish enteritis
originating from a specific pathogenic agent
(for example coccidia, Escherichia coli
O103, Clostridium spiroforme...) from those
where no clear pathogenic origin is detected
21, 33, 38
The reduction of the dietary fibre level
is a major factor that increases the incidence
of non-specific enteritis in the growing
]. However, few studies have
precisely addressed the relation between the
nutrition and the digestive pathology [23,
32, 35]. Some physiological factors
implicated in digestive troubles have been
], but several points remain
unclear. For instance, the presence of
potential pathogenic flora could presumably
increase the impact of enteritis.
Therefore, our study was aimed at
describing the digestive troubles more
precisely, using the daily control of the health
status of conventional rabbits. We used a
fibre deficient diet as a model to increase
the incidence of the digestive troubles [
that we compared to a control diet having
a standard fibre level and without change
in the origin or nature of the cell wall. We
also replicated the study with specified
pathogen free ‘SPF’ rabbits exempt of the
most known pathogens, in order to
evaluate whether sanitary status could interact
with the dietary factor.
2. MATERIALS AND METHODS
2.1. Experimental design and diets
A set of two trials was designed to test the impact of two diets with different fibre
levels on rabbit performances and health
(Tab. I). In the first one, the diet effect was
studied on rabbits with different sanitary
statuses and bred in individual cages:
conventional (group C from location A) and
specified pathogen free rabbits (group SPF
from location B). In the second experiment,
the diet effect was studied only on
conventional rabbits bred in collective and
individual cages in location A.
The two experimental diets differed
mainly in their fibre levels: a standard diet S
(ADF = 19%) corresponding to current
9, 15, 28, 29
] and a fibre
deficient diet D (ADF = 9%). In both diets,
wheat and dehydrated alfalfa meal were the
main sources of starch and fibre. The
origin and proportions of fibre fractions were
similar among diets, as well as the ratio
of digestible protein/digestible energy
(Tab. II). The diets were given in pelleted
form (3 mm of diameter), ad libitum
throughout the experiments.
2.2. Animals and housing
A total of 72 Specified Pathogen Free
rabbits (SPF) and 224 conventional rabbits
of both sexes were bred from weaning
(28 days of age) to slaughter (70 d) (Tab. I):
conventional rabbits were New Zealand
White · Californian hybrid (Toulouse,
France, strain INRA A1067), and SPF were
New Zealand White produced at INRA,
Tours, France. The SPF rabbits were obtained
free of coccidia, oxyuris, Pasteurella,
Clostridium spiroforme and enteropathogenic
Escherichia coli (O103, O132, O128, O26,
O15) . The SPF status was obtained under
highly protected conditions of breeding
(hygiene and prophylaxy). The rabbits were
individually identified and housed in wired
individual or collective cages at a room
temperature of 18 ± 2 °C and were subjected to
12 h of light. The density of rabbits per cage
was 16 rabbits.m–2. At 28 days of age, the
rabbits of each experiment were allotted to
diets according to litter origin and weaning
2.3. Control of the health status and zootechnical performances
Live-weight and feed intake were
controlled weekly. Mortality and morbidity
were controlled individually every day from
28 to 70 days of age. Morbidity control
consisted in a global external examination
(dynamic or prostrate animal), followed by
a precise observation of all clinical signs of
digestive troubles or sickness: light, acute
or finishing diarrhoea; constipation (caecal
impaction); and presence of mucus in
excreta. In addition, animals without visible
digestive troubles, but showing severe
disturbances in feed intake or growth (loss of
weight during a week or with abnormally
low growth) were classed as morbid. The
1 Containing a coccidiostatic (66 mg of robenidine per kg), 2 value measured on 16 rabbits per diet
(conventional and SPF), 3 DP = digestible crude protein, 4 DE = digestible energy.
morbidity rate was expressed as the
number of ill rabbits over the initial number of
animals, and an animal was considered
morbid only one time (within a period), even if
diarrhoea lasted several days. Dead animals
were only accounted for in the mortality
rate, even when they exhibited clinical signs
of diarrhoea before death. Therefore, we
calculated a Health Risk index (HRi)
corresponding to the sum of morbid and dead
animals, knowing that each animal was
deducted only once and categorised either as
dead or morbid. Mortality and morbidity
were calculated within periods of two weeks
(28–42 d, 43–56 d, 57–70 d) and for the
whole fattening period (28–70 d). In
addition, since health status was controlled daily,
we calculated the mean number of days with
diarrhoea (NDD) to evaluate the global
impact of the digestive troubles: (sum of
days with diarrhoea on morbid and dead
rabbits) / (initial number of rabbits). We also
attempted to qualify the digestive troubles
themselves, by calculating the mean
duration of diarrhoea (MDD) for two classes
of rabbits (ill or dead): (sum of days with
diarrhoea) / (number of rabbits, either ill or
The rabbits observed as recently dead
(within few hours) or to be dying were
subjected to an autopsy, so that symptoms and
lesions of each part of the digestive tract
associated with digestive disturbances could
be described. The dry matter level and the
pH of the caecal content were measured,
and compared to caecal content of healthy
rabbits slaughtered at the same age
(28–42–56–70 d of age). The frequency of
lesions and symptoms was calculated and
presented as a clinical table (Tab. III). In
cases of haemorrhagic caecal content, the
research of pathogenic flora such as E. coli
and Clostridium sp. was performed. In
addition, the counting of E. coli was carried out
after dilution (10–2–10–6 of 1 g of fresh
caecum content) and cultured on solid
DRIGALSKI medium (Diagnostics Pasteur,
France) at 37 °C during 24 h. Clostridium
sp. was detected by the GRAM coloration
2.4. Analytical methods
The chemical analysis of organic matter
(OM) was determined by ashing samples at
550 °C for 5 h. Measurements of fibre
fractions (neutral detergent fibre: NDF, acid
detergent fibre: ADF, acid detergent lignin:
ADL) were made according to the sequential
Van Soest procedure  using an
amylolytic pre-treatment with a thermostable
]. Nitrogen was determined by
the DUMAS combustion method using a
Leco apparatus (model FP-428, Leco Corp.,
St Joseph, MI, USA), and converted to crude
protein (CP) using the factor 6.25. Gross
energy was measured by an adiabatic
calorimeter (PARR Instrument; Moline, IL).
Starch was enzymically measured by
quantitative hydrolysis with glucoamylase (after
gelatinisation and autoclaving), and the
released glucose was then measured using
the hexokinase (EC.
188.8.131.52)-glucose-6phosphate dehydrogenase (NAD, EC184.108.40.206)
system (Boëhringer Mannheim).
The nutritive values of the two diets were obtained by measuring total tract apparent digestibility on 8 conventional and SPF rabbits per diet .
2.5. Statistical analysis
Data on growth, feed intake, mean num
ber of days with diarrhoea, and mean
duration of diarrhoea were examined by analysis
of variance using the GLM procedure of
SAS (Statistical Analysis System) . No
data from morbid animals were excluded
from growth performance calculation, to
evaluate the overall impact of the fibre
deficiency. Descriptive statistics (mortality,
morbidity, health risk, digestive lesions...) were
* Measurements from 98 necroscopy, done on recently dead or dying animals (experiment 1 and 2).
performed using the Catmod procedure and
The effect of the breeding cage
(individual vs. collective) for conventional rabbits of
location A, and sanitary status (conventional
vs. SPF) of experiment 1 were statistically
analysed in relation to the diet and their
According to dietary formulation
constraints, the fibre level decreased by 50%
from the standard to the deficient diet, and
the proportions of the different fractions of
fibre remained unchanged as determined
with the Van-Soest criteria (Tab. II). We
expressed, however, the fibre level using
only the ADF level for simplicity and
because this unit is commonly used to define
3.1. Characterisation and clinical description of digestive troubles
The individual and daily control of
rabbits from 28 to 70 days of age permitted to
detect and precisely follow the digestive
disturbances. The clinical expression of the
enteritis syndrome was essentially diarrhoea
(over 90%) independently of the diets or of
the sanitary status. Dying and dead rabbits
with enteritis were immediately autopsied.
After laparotomy, the entire tract was
photographed and the gastrointestinal segments
were more particularly examined (Tab. III).
We did not find any typical case of Rabbit
Epizootic Enteropathy (REE) and any
typical lesions of coccidia. Some microbial
cultures were done on samples from animals
with a congestive caecum wall. The
number of E. coli found in the DRIGALSKI
culture remained at a normal level (less then
106 bacteria per g of fresh caecal content).
The research of C. spiroforme by the method
of GRAM coloration was negative.
On 98 autopsied rabbits, about 98% had
diarrhoea and 48% had a distended abdomen.
A dilated ileo-caeco-colic tract (means 40%)
and a watery content (means 70%) were
the most frequent observations (Tab. III).
Besides, we detected some occurrence of
caecal impaction (20%), congestion of the
caecum (15%) and some mucus in the colon
(7%). Congestion of the caecum and its
impaction were never found in the same
animal. The dilatation of the anterior part of
caecum and its proximal segments (ileum
and proximal colon) was caused essentially
by gas, mucus or a watery digestive
content. No lesions were detected in the other
organs. The dry matter level in caecal content
for sick rabbits was lower than for healthy
ones (14% vs. 23%; P < 0.001). The pH of
the caecal content for sick rabbits tended to
be neutral, and was higher than for the
healthy ones (6.76 vs. 6.01, P < 0.001).
A sharp decrease in the feed intake and
live weight was observed two or three days
before the first symptoms of diarrhoea (90%
of cases) and during diarrhoea. Morbid
animals were generally prostrate. In 90% of
cases, the morbid animal had diarrhoea for
2 or 3 days. The 10% of the remaining cases
were loss of caecotrophes, excretion of
mucus or a decrease in feed intake and live
weight. Diarrhoea generally has 3 phases:
light or beginning diarrhoea followed by an
acute phase and then by a finishing phase.
The diarrhoea was liquid, and stained the
rectal and caudal region. Animals
surviving the acute diarrhoea recovered their
initial feed intake and weight gain within 2 to
3 days after the finishing phase of diarrhoea.
The effects of diet and sanitary status
were not significant on clinical expression of
the enteritis. The mean duration of diarrhoea
(MDD) was similar regardless the type of
cage and the diet, and no interactions were
detected between sanitary status and the
intensity of the disease (Fig. 1). For
conventional animals of experiment 1, the
diarrhoea appeared longer (3.0 ± 1.7 d)
compared to SPF rabbits (1.1 ± 0.3 d; P = 0.018).
P = 0.01
Four indicators of health status were
used: number of days with diarrhoea (NDD),
mortality rate, morbidity rate and the health
risk index (HRi). For NDD, no interactions
were detected between the sanitary status
and the diet (Fig. 2). The NDD of
conventional rabbits was 1.8 d whereas for SPF
rabbits it was only 0.3 d (P < 0.01). The
reduction of dietary fibre level for the NDD
was twice that of the control diet (P < 0.01).
No interactions were observed between
the sanitary status and the diet, neither
for mortality and morbidity nor for HRi
(Tab. IV). The mortalities remained
similar according to sanitary status, and were
respectively 16 and 22% for conventional
and SPF rabbits. The morbidity and the HRi
were 7 times and 2.3 times less in SPF rabbits
compared to the conventional ones
(P < 0.01). For conventional rabbits, HRi
was caused essentially by morbidity which
represented 2/3 of HRi (1/3 by the
mortality). However for SPF, HRi corresponded
mainly to mortality.
Mortality and HRi were respectively
2.7 times (P = 0.024) and 1.4 times (P = 0.017)
higher with the deficient diet compared to
the standard one, whereas no effect of diet
on morbidity was observed (mean 33%). If
we consider that excretion of caecotrophes
for 3 successive days is a symptom of
digestive troubles, then morbidity level increased
by 30% and reached 98% (28–70 d period)
for conventional rabbits fed diet D. With
the standard diet, morbidity was similar with
or without considering the caecotrophes in
the calculation of morbidity (41% vs. 37%).
Digestive troubles were distributed
differently along with growth for conventional
and SPF rabbits. For SPF rabbits, digestive
troubles appeared mainly during the 28–42 d
period, whereas for conventional rabbits,
enteritis was expressed essentially between
43–56 d of age. These two periods
represented about 50% of the digestive
disturbances, with the fibre deficient diet.
Although, the interaction between the diet
and caging effect tended to be significant
for mortality and morbidity (P < 0.10,
Tab. V), the mortality rate was higher in
collective cages compared to individual ones
(34.6 vs. 17.0%, P < 0.01) for the whole
fattening period. Conversely, morbidity
appeared significantly higher for
individually caged rabbits (+ 20 units), resulting in a
similar global incidence of digestive
troubles (means of HRi = 70%).
3.3. Feed intake and growth performances
A relatively high variability affected the
zootechnical performances, since data from
morbid animals were not discarded. We
observed an interaction between the
sanitary status and the diet for intake, growth
and final live weight (Tab. VI). For
conventional rabbits fed the standard diet, the
intake, the final live weight and the total
weight gain were 5% higher compared to
SPF rabbits. With the fibre deficient diet,
the SPF rabbits had a higher intake and
higher final live weight and growth
(respectively + 15%, + 6% and + 10%; P < 0.001).
Globally, the reduction of the dietary ADF level (19 vs. 9%) led to a 3-fold reduction in ADF intake (28–70 day period), while the starch intake only increased two
fold (means 11 to 28 g.d–1). The feed
conversion (FC) and the energetic conversion
index (ECi, MJ DE.kg–1 LW gain) were
respectively 0.74 and 1.37 units lower for
the D diet compared to the S diet (2.24 vs.
2.98, and 29.26 vs. 30.63 MJ DE.kg–1 LW
gain, P < 0.01).
During the period 43–56 d, parallel to
the peak of enteritis, decreases of 44% and
24% (P < 0.01) were observed respectively
for the feed intake and growth with the D
diet compared to the S diet. The peak of
enteritis with the D diet was two weeks
earlier (28–42 d) in SPF rabbits, but the intake
a Root mean square error; n: number of rabbits.
was only reduced by 28% and growth by
8% (P < 0.01). In addition, the variability
(Root Mean Square Error) of the final
weight seemed lower in SPF rabbits than in
conventional ones (111 vs. 255 g).
4.1. Methodology and diagnostic of digestive disorders
The methods employed in this study were
aimed at precisely describing the digestive
troubles caused by a fibre deficiency in
conventional and SPF rabbits. Although not
complex, this approach was time consuming
since daily control of health was essential.
Evaluating the morbidity and mean
duration of diarrhoea is not original itself, and
has been extensively used in some other
species (e.g. pigs). However, few studies
have used this methodology to describe
nonspecific enteritis in the growing rabbit [
]. Furthermore, the calculation of a
health risk index (HRi = mortality +
morbidity) for a group of animals improves the
evaluation of the health status and the impact
of enteritis, that are greatly underevaluated
if only mortality is recorded. Here,
morbidity represented more than 60% of the health
problems. Till now, no studies have
controlled the daily rabbit health status during
the whole fattening period, except that of
Rémois et al. .
In agreement with Licois [
was the predominant and constant clinical
sign observed in rabbits with enteritis. The
clinical table was consistent with a
previous study of Vörös . In diarrhoeic
rabbits, we also found a higher caecal pH,
which is habitual in sick animals [26, 31],
that could be related to a lower VFA level as
described by Gidenne [
While descriptions of diarrhoea have
been widely carried out on infectious
diseases in the rabbit [
5, 24, 25, 34, 41
], little is
known about diarrhoea linked to nutritional
factors [26, 31, 40]. In our experiment, more
than 90% of morbid rabbits had diarrhoea.
Only 10% agonising rabbits showed
symptoms of infection (such congestive caecum),
but microbial culture did not reveal a
significant level of E. coli or C. spiroforme,
the most frequent bacteria encountered in
rabbits and known to induce infectious
enteritis. Besides, the clinical expression of
the digestive pathology here was similar
with respect to the sanitary status or the
effect of the diet.
4.2. Effect of sanitary status
Pathogenic agents, such as E. coli or
Clostridia, are frequently detected at low
levels in healthy rabbits. To test if the impact
of a non specific enteropathy, caused by
fibre deficiency, could be dependant or not
on a potentially associated pathogenic flora,
we compared conventional and SPF rabbits.
Whatever the diet, the post-weaning
mortality was not significantly affected by the
sanitary status, contrary to morbidity which
was seven times lower for SPF.
Furthermore, the intensity of the digestive troubles
was weaker for SPF than for conventional
rabbits (duration of diarrhoea and the
number of days with diarrhoea). The sanitary
status interacted with the dietary fibre level
only for growth parameters. The increased
incidence of non-specific enteropathy for
conventional rabbits impaired their growth
and their final weight, as previously observed
by Gidenne et al. [
]. Conversely, SPF
rabbits were less affected by the fibre deficiency
since they showed a similar growth for both
diets. Our results were in agreement with
the observations of Licois et al.  who
reported a lower mortality and morbidity
for SPF rabbits (10–15%) than for
conventional ones (60%), when they were
contaminated by Rabbit Epizootic
Enteropathy. This effect of the sanitary status could
be linked to the balance of the ecosystem
(flora free of pathogenic agents), as well to
the strict sanitary conditions of breeding of
SPF rabbits before weaning . In return,
conventional rabbits potentially having
pathogenic microbes, showed a lower
resistance to non-specific enteropathy.
4.3. Impact of dietary fibre level
Few authors have studied the digestive
disturbances in relation to the dietary fibre
level, without change of the proportions of
the cell wall [
3, 17, 18
]. Here, a sharp
decrease of the fibre level (19 to 9%)
doubled the risk of digestive troubles after
weaning. The fibre deficient diet also increased
the incidence of digestive disorders by losses
of caecotrophes, and then morbidity reached
98% for conventional rabbits. Maître et al.
 found that mortality increased from 7.5
to 14.4% when the level of dietary fibre
decreased (21 to 15% of ADF). Gidenne
and Jehl  indicated that HRi and
morbidity tended to increase between 28–70 d of
age, even when mortality remained not
significantly affected by the reduction of the
dietary fibre level (20 to 16% of ADF).
Moreover, an increased incidence of
enteropathy with a fibre deficient diet led
to losses of performances in conventional
rabbits, as previously described [
10, 15, 18
Some hypotheses were suggested to explain
the effect of dietary fibre on rabbit
enteropathy. A direct effect of a fibre level
reduction is a slowing down of the digestive
transit, corresponding mainly to a longer
retention time in the caecum [
2, 12, 18
Long retention time would probably be
induced by a higher proportion of fine
particles in a low-fibre diet, thus inducing
change in the caecal motility pattern. On
the contrary, fibre deficiency greatly affects
the caecal fermentation pattern and impairs
the caecal microbial activity [
2, 15, 18
the level of cellulolytic flora . All these
changes in microbial activity could thus lead
to an unbalanced ecosystem and to a weak
barrier effect of the caecal flora, finally
favouring the incidence of enteropathy.
Conversely, the level of the fibre in the
diet was generally inversely correlated to
the level of the starch. Cheeke and Patton
 suggested that a high starch level in the
diet would promote a carbohydrate
overload in the hindgut, and may favour the
proliferation of a pathogenic agent such as
Clostridium sp. However, with low fibre
feeds, Gidenne et al. [
] showed a very
high ileal digestibility of starch (> 93%) in
the adult, and they estimate that starch ileal
flow in 6 week old rabbits remained under
2 g.d–1, even with a 30% dietary starch level.
Nevertheless, before 6 weeks of age, the
secretion of pancreatic amylase is not well
established  and the starch ileal flow
could be higher and may partly explain the
appearance of enteropathy two weeks
postweaning. On the contrary, Pinheiro and
Gidenne  have found an interaction
between the age and nature of starch. They
detected a higher ileal level of starch for
42 d than for 70 d old rabbits (resp. 1.4 vs.
0.8%), but using feed containing a resistant
starch (crude potato) or starch from wheat.
The ileal starch digestion remained very
high, even with a 14% dietary addition of
resistant starch. Therefore, the relationship
between resistant starch addition and
morbidity was moderate, and was not
significant for mortality. Furthermore, with respect
to rabbit age, the peak of appearance of
enteropathy could vary largely with fibre
deficiency among the studies: after 42 d
of age for Gidenne et al. [
] and around
43–56 d of age for the present study (for
conventional rabbits). This did not support
the role of starch overload on enteropathy,
since after 6 weeks of age, starch digestion
is almost complete in the rabbit intestine.
In conclusion, a fibre deficiency clearly
impairs the health status of the conventional
growing rabbit (caged collectively), and
more particularly morbidity after weaning.
Morbidity, such as transient diarrhoea or
growth disturbances, represented more than
50% of the health problems. Compared to
SPF rabbits, the presence of potentially
pathogenic flora in conventional animals
(caged individually) clearly promoted
morbidity and not mortality. A correct fibre
supply acts as a factor of prevention so that the
background morbidity level (mainly linked
to the sanitary status) does not evolve into
mortality. Thus, non-specific diarrhoea
depends jointly on sanitary and nutritional
status of the animals. The digestive
microflora and the role of fibre on
microbial activity should be further studied to
clarify the relationship between fibre intake
and digestive pathology of the rabbit.
The authors thank P. Aymard and A.
Lapanouse (INRA, Station de Recherches
Cunicoles) and M. Dupuy and J.-P. Molteni (INRA,
Pathologie Aviaire et Parasitologie) for their
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