Thirty six 25-day-old suckling rabbits and thirty six 29-day-old rabbits weaned since one day were orally vaccinated with one of the two doses (3.5 x 103 or 3.5 x 104 oocysts) of a precocious line of Eimeria magna. Only the groups vaccinated with the highest dose displayed a vaccine reaction, but without diarrhea or mortality. A vaccination totaly or incompletely protected against disease, assessed by daily growyh rate patterns, according to the dose given and reduced oocyst output 10 to 1000 times, measured between the 4th and the 10th day following the challenge inoculation.

Two-day-old suckling rabbits of a selected strain (NZW) imported from a temperate country (France) were suckled in a tropical country (Benin) by does of the local strain (CECURI). The growth performance of the imported and native rabbits was compared after weaning at 31 days, in a 8 weeks fattening trial. Four groups were constituted: 2 x 24 weanlings of each strain were fed either with the local feed (coarsely ground meal + green forage) or with a balanced pelleted diet imported from France. No morbidity was observed during the trial. NZW and CECURI rabbits had the same growth rate when fed pelleted feed: 29.6 and 28.5 g/day respectively. This performance was only 10 to 22% lower than in temperate countries and the main reason was a lowered feed consumption in relation to temperature. The growth rate of CECURI rabbits fed on the local feed was lower than that of the group of the same strain fed on pelleted diet. The difference was only 18 % and mainly carne from a lower dry matter intake (72.5 vs 84.7 g/day for pellets) The imported strain had difficulties of adaptation not to the climate but to the local feed. His growth rate was only 19.4 g/day vs 23.4 g/day for the local rabbits receiving the same feed. A potential effect of the early chemosensory experience (during both gestation and first suckling) of the imported strain is discussed. In their conclusion, the authors emphasised that neither the climate, nor the feed presentation can explain the very low growth rates (10 to 15 g/day) too frequently mentioned in the literature for post weaning growth experiments conducted with New Zealand rabbits raised in tropical conditions.

Fifty two coccidia free rabbit does were used in this experiment and 26 of them were immunized by repeated per os inoculations of 104 oocysts of Eimeria magna precocious line during gestation. The oocysts output was completely controlled after the third inoculation and signs of disease were never observed. The serum antibodies (Ab) were titrated by an ELISA method. In the controls, the Ab titers were constantly below the optical density 0,25 at the wave length 405nm. In immunized does, the Ab level began to increase 4 weeks after the first inoculation. Booster inoculations given 7 and 4 days before parturition produced a high increase of Ab level. 26 females received an injection of sporozoites 2 and 17 days after parturition; these injections produced a dramatic increase of the Ab level compared with that of the untreated females. The serum Ab of the weanlings were titrated at 29 and 39 days of age. In all groups, the Ab titers were very low but a slightly higher level was observed in the groups corresponding to the immunized does. The dramatic increase of the Ab titers of the does injected with sporozoites had no effect on the Ab titers of their litters. To test the protection transmitted by the mothers, the weanlings were inoculated with 10 oocysts of the same Eimeria magna precocious line and the oocysts output was measured. The whole excretion of oocysts was identical (6 x 10 oocysts) in all groups, and the decrease in weight gain was identical to that of inoculated controls. We can conclude that the does immunity did not protect the litter against an infection with E.magna.

A total of 80 two-day-old suckling rabbits of a selected New Zealand White rabbit strain imported from a temperate country (France) were suckled in a tropical country (Benin) by foster does of the local population. The growth performance of the imported rabbits and of 81 native rabbits suckled by the same does was compared. No morbidity was observed in both groups. Growth rate was identical in both groups up to 21 days i.e. the end of the exclusive milk feeding: 10.2 and 10.5 g/day for imported and native rabbits respectively. During the last period befare weaning (21 to 31 days) the group of imported sucklings had a lower growth rate (13.0 vs 17.1 g/day). This period corresponds to the beginning of salid food consumption. A genetic adaptation of the local rabbits to the local feed and/or climate, or, more probably, an effect of the early chemosensory experience (during both gestation and first suckling) of the imported strain are discussed.

Soixante-quatre lapins EOPS (exempts d'organismes pathogénes spécifiés), âgés de 4 a 6 semaines ont été répartis en deux lots égaux. L'un (TC), a été traité pendant 3 semaines avec un corticoide, la déxamétasone, à raison de 3 injections de 4 mg/kg, par semaine. L'autre lot (NT), a reçu seulement des injections d'eau physiologique. Aprés 19 jours de traitement, l'ensemble des animaux a été inoculé par voie orale, avec du broyat digestif susceptible d'induire l'Entérocolite Epizootique du Lapin (EEL). Les résultats ont montré qu'avant l'inoculation, la croissance a été fortement réduite dans le lot traité à la déxamétasone: poids vif réduit de 24% par rapport au lot non traité. L'inoculation a entraîné une élévation considérable de la mortalité dans le lot TC: 65,5%, contre 13,8% dans le lot sans corticoide, au cours des 9 jours d'observation ayant suivi l'inoculation. Les lésions caractéristiques de l'EEL ont été retrouvées chez 74% des lapins morts dans le lot TC et chez 100% de ceux du lot NT. La mortalité est apparue un jour plus tôt chez les lapins TC: à J2 post-inoculation, vs J3 pour le lot NT. Dés J1, des lésions spécifiques de l'EEL ont été détectées dans le lot TC. Ce modèle expérimental animal (immunodépression de lapin EOPS) constitue une avancée capitale pour la suite des travaux sur l'EEL.

This paper describes the genetic variability for the resistance to three digestive stresses in the growing rabbit: after inoculation of coccidia (trial “coccidia”), with a fibre deficient diet (trial “FD”), and after experimental reproduction of epizootic rabbit enteropathy (trial “ERE”). Genetic variability was analysed from a sample of 48 sires, which produced the experimental young rabbits. These animals were examined on D0, D4, D11, D18, D25 and D32 after weaning (at 30 days old). Three clinical symptoms were checked: bloated abdomen, diarrhoea and mucus. Mortality and clinical symptoms were used to assess an individual response to each digestive stress. Two binary indexes were defined to describe this rabbit individual response. The first one (“Alive”) dealt with mortality. The second (“Tolerant”) dealt with mortality and morbidity. “Alive”, and “tolerant” percentages were low for the “coccidia” trial (61% and 23% respectively), high for the “FD” trial (75% and 36% respectively) and intermediate for the “ERE” trial (66% and 37% respectively). The sire effect was significant for each index in the “coccidia” and the “FD” trials. The sire effect was significant for the “tolerant” index in the “ERE” trial. Correlations between sire rankings for the two indexes of one trial were often significant. Correlations between sire rankings for indexes of “coccidia” and “FD” trials were weakly significant. Our results demonstrate that there is a genetic variability for the resistance to three different enteropathies.

Viability and growth of 191 kits born alive from 33 does from a local population was studied in tropical conditions (Benin) in relation to achieving the initial sucking. After observing the state of the kit?s belly at the first control, each kit was weighed and classified as suckled (S) or non suckled (NS), and returned to it?s mother?s nest box. On average 34% of kits were considered to be in the NS group. The proportion ranged from 15% in very small litters (2-3 born alive) to 42% in the largest litters observed (8-9 born alive). Apparent live weight of NS kits was significantly lower than that of S kits: 40.4 vs. 53.6 g. The weight difference was not related to litter size. Birth to weaning mortality (0-35 d.) was significantly higher for NS kits than for S kits: 36.9% vs. 13.5%. But of those kits which died during the lactation period, the proportion of deaths during the first week of life was almost identical for NS and S kits: 66.7% and 64.7%. Birth weight of non suckled kits which died before weaning was significantly smaller than that of non suckled kits alive at weaning time: 37.6 vs. 42.0 ± 7.9 g without any significant interaction with litter size. However, for suckled kits, the corresponding difference was smaller and non significant: 51.4 vs 53.9 ± 8.0g again without interaction with litter size. The average 0-35 days growth rate was not affected by the initial sucking (NS 12.23 and S 12.21 g/d). Nevertheless an interaction with litter size was observed (P=0.091): in small litters (2-5 kits born alive) NS kits had a lower growth rate than those of the S group (12.8 vs. 14.2 g/day), while in larger litters (6-9 kits) the reverse was observed (12.1 vs. 11.1 g/day). Careful observation of newborn kits would allow stockbreeder to reduce mortality among young rabbits in a critical situation.

A study of some non genetic factors influencing the mortality from birth to weaning of young rabbits was realized from records on 1821 litters from 11 rabbit farms in the south of Benin, from December 2001 to January 2004. The mortality rate from birth to weaning was recorded and analysed by GENMOD procedure. The mortality rate from birth to weaning varied according to the rabbit farm (P < 0.001). The mortalities rate from birth to weaning increased from 11 to 19%, corresponding respectively to the first and the twelfth litter orders. The mortality rate increased significantly (P < 0.001) from 12% to 17%, according to the litter size.

A study was carried out in 2000 to evaluate the level of the technical management of the rabbit farms of South-Benin. Four farms were included into the investigation. Data collected by the farmers made it possible to note the mean level of the zootechnical performances. The average litter size was 6. An average of 5.6 kits were born alive of which 4.8 were weaned. The interval between littering was evaluated to 73 days, thus, an average of 6 litters per year can be counted. Considerable variations were observed among the farms in some zootechnical parameters such as the number of born alive per litter. Results of this study show that there is an exploitable genetic characteristic on the level of the rabbit breeding in Benin.

The endogenous cycle of Eimeria flavescens was studied in specific pathogen-free rabbits by means of histology and transmission electron microscopy. In total, five asexual generations were observed and two types of meronts and merozoites were found in each generation. Type A gave rise to a smaller number of thick polynucleate merozoites in which daughter merozoites were formed by endomerogony, while in the type B meronts slender uninucleate merozoites arose from ectomerogony. The first generation meronts were found in the crypts and proximal part of the villi of the duodenum and jejunum, whereas the three following generations developed in the superficial epithelium of the large intestine (cecum, vermiform appendix and colon). The last merogony as well as gamogony took place in crypts of the large intestine.

Primary infection with Eimeria intestinalis confers very effective immunity against further infections in rabbits. This study was designed to determine the onset of the immune response in primary-infected rabbits and to characterise the immune status of protected rabbits. Variations in kinetics of CD4+ and CD8+ T-cell subpopulations were followed after primary infection at the intestinal sites of penetration (duodenum) and development (ileum), in mesenteric lymph nodes (MLN) and in the spleen. The response against the parasite was measured by specific lymphocyte proliferation in the spleen and MLN and by determining specific IgG titres in serum. The mucosal immune response was strong after primary infection and was characterised by (i) transient increase in the percentages of intestinal CD4+ lymphocytes and MLN CD8+ lymphocytes 14 days PI and (ii) strong increase in the percentages of intestinal CD8+ lymphocytes from 14 days PI persisting throughout further infections. Extensive infiltration of the lamina propria with CD8+ lymphocytes was observed 14 days PI. The specific proliferative response started between 7 and 14 days PI in MLN but remained undetectable in spleens for up to 21 days, in contrast to "immunised" rabbits. The fact that systemic immune responses were low after primary infection, in contrast to indicators of mucosal immune responsiveness, suggests that protection of rabbits against E. intestinalis infection is due to an effective mucosal immune response, and that systemic responses that increase after successive infections are only reflections of repeated encounters with parasite antigens.

The fine structure of sporocysts and sporozoites of parent strains and precocious lines of rabbit coccidia Eimeria intestinalis, E. magna and E. media was studied. The parent strains and precocious lines differ only in the shape and size of refractile bodies (RB). In the sporocysts of precocious lines of E. magna and E. media, one extremely large RB was seen, either inside one of the sporozoites, or free in the sporocyst. In the oocysts of the precocious strain of E. intestinalis, two sporocysts resembled those of the precocious lines of E. magna and E. media, whereas the other two sporocysts did not harbour any RB. Sporozoites of all the precocious lines contained no, or very small, RB after in vitro excystation.

The endogenous development of the rabbit coccidium Eimeria vejdovskyi was studied in SPF rabbits using light and electron microscopy. All endogenous stages were seen in the ileal epithelium. There were two types of meronts in each of five asexual generations. Type A produced fat, polynucleate merozoites while type B meronts had slender uninucleate merozoites. First- second- and third-generation meronts were in the crypts. The first meronts were at the bottom of the crypts, very often in the Paneth cells. The meronts of the fourth generation were in the middle of the villi; the fifth-generation meronts were recorded in the middle and at the top of the villi. The prepatent period was 10 days.

Two-day-old suckling rabbits of a selected strain (NZ) imported from a temperate country (France) were suckled in a tropical country (Benin) by does of the local strain (CECURI). The growth performance of the imported end native rabbits was compared after weaning at 31 days in a 8 weeks fattening trial. Four groups were constituted: 24 weanlings of each strain were fed either with the local feed (coarsely ground meal + green forage) or with an imported balanced pelleted diet. No morbidity was observed during the trial. NZ and CECURI rabbits had the same growth rate when fed with pelleted feed : 29.6 and 28.5 g/day respectively. This performance was only 10 to 22% lower than in temperate countries and the main reason was a lowered feed consumption in relation to temperature. The growth rate of CECURI rabbits fed on the local feed was lower than that of the group of the same strain fed on pelleted diet. The difference was only 18 % and mainly came from a lower dry matter intake (72.5 vs 84.7 g/day for pellets) The imported strain had difficulties of adaptation not to the climate but to the local feed. His growth rate was only 19.4 g/day vs 23.4 g/day for the local rabbits receiving the same feed. A potential effect of an early chemosensory experience (during both gestation and first suckling) of the imported strain is discussed.

A total of 80 two-day-old suckling rabbits of a selected NZW strain imported from a temperate country (France) were suckled in a tropical country (Benin) by does of the local strain. The growth performance of the imported rabbits and of 81 native rabbits suckled by the same does was compared. No morbidity was observed in both groups. Growth was identical in both groups up to 21 days i.e. the end of the exclusive milk feeding: 233 and 232 for imported and native rabbits During the last period before weaning (21 to 31 days) the group of imported sucklings had a lower weight gain.(13.0 vs 17.1 g/day) This period corresponds to the beginning of solid food consumption. A genetic adaptation of the local strain to the local feed and/or climate, or the potential effect of the early chemosensory experience (during both gestation and first suckling) of the imported strain are discussed.

Eighty to 100% of rabbits at weaning am spontaneously and heavily infected with Pneumocystis (P. carinii sp.f. oryctolagi). Lung and other tissues have been Bound infected with Pneumocystis after microscopic examination, immunofluorescence or PCR. However; the infection source, the method of entry of Pneumocystis organisms into the rabbit and when they become infected remain to be known. The parasite rate was highest at weaning. As a few parasites were microscopically observed at birth and detected by PCR, in utero Pneumocystis infection was hypothesised. Thus, four pregnant does and their foetuses or embryos were examined. Pneumocystis was detected by PCR in maternal blood, foetuses, embryos and amniotic fluid. It was also revealed histologically and immunofluorescence in foetal and maternal lungs and placentas. Results suggest that transplacental transmission of Pneumocystis occurs as early as at the 15th of pregnancy.

The frequency of the carriage and the enumeration of Escherichia coli was determined in caecal content of 15- to 49-day-old, SPF rabbits. Results, expressed as the percentage of rabbits in the different class intervals of the log of E. coli populations, showed a high proportion of rabbits with no detectable E. coli (<10(2) E coli/g, which is the treshold of the method used): 25% on day 15, 12% on day 22 and 30% later. Consequently the distribution of animals in the different classes is statically not normal. The mean level of E coli population in rabbits harbouring colibacilli were at least of 10(7) bact/g, on days 15 and 22 and then decreased to 10(4)-10(5) bact/g, on days 42-49. As a result, this makes the interpretation of a general mean including the first class interval (<10(2) E. coli/g), very difficult. Moreover, the distribution of animals does not allow variance analyses if this class interval is included. This means that, in the rabbit, it would be necessary to dissociate the two parameters which are the frequency of animals without detectable E coli and the enumeration of colibacilli in animals harbouring this bacteria.

Although immunodeficiency represents the main etiopathogenetic factor [1], the basic mechanism of Pneumocystis carinii pneumonia (PCP) pathogenesis remains poorly understood. When growing into alveoli, P. carinii interacts with cells and other components; the initial stages of PCP involve parasite attachment to alveolar epithelium, preferentially to type I pneumocytes [2–5], and produce an increase in alveolo-capillary permeability [5, 6]; this last event leads to an influx of plasma proteins into the alveolar space and thereby may alter the composition of epithelial alveolar lining fluid. Pulmonary surfactant, which covers the alveolar surface, plays an important role in the homeostasis of the alveolar environment and in the defense of the lung [7–11]. Since P. carinii comes into close contact with surfactant, it seems logical to suppose, on the one hand, that the parasite could interact with surfactant components and, on the other hand, that pulmonary surfactant may have an impact on the pathophysiology of PCP. Pulmonary surfactant, which is synthesized by alveolar type II cells, is a complex material containing lipids and proteins (Table 1) [7, 8]. Its synthesis is developmentally regulated in fetal lung and can be accelerated by glucocorticoids and other hormones [12]. Lipids are the main components (90%) of pulmonary surfactant [7, 8]. Phospholipids represent 80–90% of the lipids and phosphatidylcholines, which are mainly dipalmitoylphosphatidylcholines, constitute the major part (70–80%) of phospholipids. Cholesterol comprises the largest amount of neutral lipids. In addition to lipids, four surfactant-specific proteins (SP) with different structural properties have been identified [13, 14]: SP-B and SP-C, which represent only 1% of total surfactant, are two extremely hydrophobic proteins; they are involved in keeping surface active properties of the surfactant [14, 15]. SP-A and SP-D are hydrophilic proteins; SP-A …

APMISVolume 105, Issue S77 p. 5-6 Improved rabbit model of Pneumocystis carinii pneumonia: induced infections in Pneumocystis-free animals Preliminary results N. CERÉ, N. CERÉ INRA, Centre de Tours, Station de Pathologie Aviare et de Parasitologie, F-37380 NouzillySearch for more papers by this authorB. POLACK, B. POLACK Ecole National Vétérinaire d'Alfort, 7 avenue du Général De Gaulle, F-94704 Maisons-AlfortSearch for more papers by this authorP. COUDERT, P. COUDERT INRA, Centre de Tours, Station de Pathologie Aviare et de Parasitologie, F-37380 NouzillySearch for more papers by this author N. CERÉ, N. CERÉ INRA, Centre de Tours, Station de Pathologie Aviare et de Parasitologie, F-37380 NouzillySearch for more papers by this authorB. POLACK, B. POLACK Ecole National Vétérinaire d'Alfort, 7 avenue du Général De Gaulle, F-94704 Maisons-AlfortSearch for more papers by this authorP. COUDERT, P. COUDERT INRA, Centre de Tours, Station de Pathologie Aviare et de Parasitologie, F-37380 NouzillySearch for more papers by this author First published: 11 October 2011 https://doi.org/10.1111/j.1600-0463.1997.tb05372.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume105, IssueS77December 1997Pages 5-6 RelatedInformation

Although vertical transmission of Pneumocystis in human or animal hosts has often been suspected, no evidence demonstrating this infection route has been furnished until now. This widespread parasite is constantly found in the lungs of rabbits, which spontaneously develop a benign pneumocystosis at weaning. However, the infection source, the method of entry of Pneumocystis organisms into the rabbit and when this mammal is infected, remain to be known. As a few parasites have been microscopically observed and detected by PCR in the lungs of rabbits at birth, in utero Pneumocystis infection has been hypothesized. The presence of Pneumocystis was therefore carefully assessed in 16 pregnant does, their embryos and fetuses by using several detection methods. Pneumocystis was detected by PCR in maternal blood, embryos, amniotic fluid and fetuses. The parasite was also revealed histologically and by immunofluorescence in fetal and maternal lungs and in placentas. The results suggest that vertical transmission of P. carinii sp, f. oryctolagi occurs as early as at the 10th day of pregnancy.