Caecal Lesions Research Articles

The isolated caecal patch lesion: a clinical, endoscopic and histopathological study

ObjectiveTo describe and investigate the potential causes of the isolated caecal patch lesion, a previously undescribed endoscopic phenomenon of a lesion fulfilling endoscopic and histopathological criteria for chronic inflammatory bowel...

Comparison of the clinical signs, pathological and immuohistochemical findings in visceral organs of chickens experimentally infected with Salmonella Zega through three routes

Salmonella Zega isolated from natural outbreaks that were characterized by high mortality in poultry farms in three Southwestern States of Nigeria was used to inoculate two week-old chicks through different routes in order to determine and compare the clinical signs, pathological and immunohistochemical changes in each route of infection. The birds were divided into 4 groups of 25 each as groups A (orally inoculated), B (intraperitoneally inoculated), C (inoculated per cloaca) and D (uninoculated control). All the birds were inoculated with 0.2 ml of 1 × 108 cfu of the bacteria. Clinical signs were observed and recorded according to the route of infection, and with the days post-infection from day 0 till day 10 post-infection. Two birds from each group were sacrificed every 24 h and examined for gross lesions, which were described and scored according to the route of infection and days post-infection. Samples of visceral organs were collected for bacteriology, histopathology and immunohistochemistry. Clinical signs in chicks infected orally and intraperitoneally were weakness, anoraexia lethargy, somnolescence, yellowish diarrhoea observed from 4 days till day 10 post infections. Mild sign of weakness was observed in chickes infected per cloaca, from day 3 to 7. The gross lesions were congestion, oedema and enlargement and necrosis in visceral organs from day 4 to 10 post infection in orally and intraperitoneally infected chicks, but mild vascular changes were observed in chicks infected per cloaca, except in the caecum were lesions of necrosis and infiltration of inflammatory cells were moderate to severe. Microscopic lesions were necrosis of host cells and infiltration by lymphocytes, heterophils and macrophages in multiple organs observed from day 4 to 10 post infection in orally and intraperitoneally infected chicks. Immunoreactions were observed in all the visceral organs examined. Clinical signs, pathological and immunohistochemical findings were mild in chicks infected per cloaca, except caecal lesions. Salmonella Zega isolated from an outbreak in poultry farms in Abeokuta, Nigeria was highly pathogenic in chicken and produced similar findings in oral and intraperitoneal infections; while per cloacal infection showed a localized infection of the caecum.

Efficacy of a commercial herbal formula in chicken experimental coccidiosis

BackgroundCoccidiosis represents a serious threat to the poultry industry, affecting production and causing high morbidity, mortality and significant costs resulting from treatment and prophylaxis. In-feed anticoccidials have been used for decades for managing avian coccidiosis and were very effective until drug resistance emerged. The use of natural remedies has become a promising alternative in combating coccidiosis in chickens. Therefore, the purpose of the present study was to assess the efficiency of a commercial herbal formula (H), as oral liquid preparations, in experimental chicken coccidiosis.MethodsTwo independent controlled battery experiments (BE1 and BE2) were designed and the product was tested in 3 different formulas (H1, H2 and H3): H1 contained a propylene glycol extract of Allium sativum and Thymus serpyllum; H2 contained Origanum vulgare, Satureja hortensis and Chelidonium majus; and H3 contained Allium sativum, Urtica dioica, Inula helenium, Glycyrrhiza glabra, Rosmarinus officinalis, Chelidonium majus, Thymus serpyllum, Tanacetum vulgare and Coriandrum sativum. Chickens were divided into five groups for each BE as follows: (i) uninfected untreated control (UU1, UU2); (ii) infected untreated control (IU1, IU2); (iii) infected treated with amprolium (ITA1, ITA2); and (iv, v) two experimental groups infected treated with H1 (ITH1) and H2 (ITH2) formulas in the BE1 and with H3 (ITH3-5 and ITH3-10) formula in the BE2. The chickens from infected groups were challenged with 5000 (BE1) and 50,000 (BE2) sporulated oocysts of Eimeria spp. (E. acervulina, E. tenella and E. maxima), respectively. The anticoccidial efficacy was assessed by recording the following: oocysts output (OPG), lesion score (LS), weight gain (WG), feed conversion ratio (FCR) and anticoccidial index (ACI). Additionally, polyphenolics and flavonoids (caffeic-chlorogenic acid, apigenin, kaempferol, luteolin, quercitin, quercitrin) from herb extracts found in H3 formula were determined by the liquid chromatography-tandem mass spectrometry (LC-MS/MS) method.ResultsH1 and H2 reduced the WG, and increased the FCR and OPG compared with controls. H1 reduced the duodenal lesions, whilst H2 reduced the caecal lesions, compared with control. H3 decreased the OPG of Eimeria spp., reduced the total lesion score and improved the zootechnical performance (weight gain and feed conversion ratio). According to ACI value, H1 and H2 had no efficacy on Eimeria spp. infection, but H3 had good to marked anticoccidial effect, the ACI being slightly greater in the group ITH3-5. According to the results of LC-MS/MS, the concentration of polyphenols in H3 formula was the highest, the sum of chlorogenic acid and caffeic acid being 914.9 µg/ml.ConclusionsH3 formula is a promising natural anticoccidial and field trials are recommended in order to validate the obtained data.

Consequences of Concurrent Infections with <i> Ascaridia Galli</i> and<i> Eimeria </i>in Broiler Chickens

Ascaridia galli and Eimeria species constitute the aetiology of ascaridosis and coccidiosis respectively in chickens, and the two diseases are the most important internal parasitic infections that militate against the development of the poultry industry.  Natural infections of both parasites are known to occur in chickens but it is not yet fully known how conjoint infections with both parasites can influence the pathology they inflict cause to the chickens.  A. galli has been reported to enhance the pathogenicity/pathology of Pasteurella multocida and Escherichia coli when the organisms occurred concurrently with the nematode.  This study was therefore conducted to investigate the influence of A. galli to the response of two-week old broiler chickens to single and concurrent infections with the parasites either given at the same time or at different times with the hope that the results would greatly inform decisions to be taken in mitigating the infections.Forty two broiler chickens were used for the study.  The birds were allocated into six groups of 7 birds each and placed in separate pens.  Five of the groups were either infected with A. galli only, caecal Eimeria isolate only,  A. galli and caecal Eimeria isolate at the same time, A. galli and later caecal Eimeria isolate or caecal Eimeria isolate and later A. galli while the sixth group remained as uninfected controls.  The dose levels used were 1000 embryonated A. galli eggs and 12,000 sporulated Eimeria oocysts per chicken by oral administration.  Packed cell volume (PCV), body weight (BW), feed consumption (FC), faecal egg counts (EPG), faecal oocyst counts (OPG), caecal gross lesion score (GLS) for Eimeria infected birds, clinical signs and worm burdens (WB).  The infections had a negative impact on the birds evident by low PCV, low BW gain, reduced feed consumption, listlessness, bloody diarrhoea and mortalities when compared with the uninfected controls that did not exhibit such effects. A drop in the PCV from day 8 to day 12 of the birds infected with A. galli and later Eimeria group occurred following the administration of the protozoan infection.  The A. galli and later Eimeria group also had the least weight gain from day 12 to day 42.  Similarly their feed intake was also least from day 10 to day 26 in the A. galli and later Eimeria group in comparison with all the other infected and the uninfected control birds.  The greatest mortalities (5 birds) also occurred in the A. galli and later Eimeria group.It was concluded that the infections lead to poor performance of the chickens, however, the effect of the infection was severest in the chickens that were infected with A. galli and later with Eimeria.  It was suggested that A. galli caused immunedownregulation of the chickens allowing the Eimeria to exert maximally its pathogenic effects on the birds.  It was also suggested that the initial A. galli infection possibly attracted influx of large numbers of macrophages into the lamina propria where they in turn greatly enhanced the transportation of sporozoites from the lamina propria into the glands of Lieberkuhn. EPG, OPG and worm counts were not so high suggesting that both A. galli and Eimeria somewhat inhibit each other to an extent.  It is therefore strongly recommended that the infections should be diagnosed regularly and controlled promptly when present particularly if they are concurrent as the effects can be disastrous in situations where A. galli infections precede Eimeria infections as in the semi intensive and free range systems of poultry production. Â

Phenotypic and genetic variation in the response of chickens to Eimeria tenella induced coccidiosis

BackgroundCoccidiosis is a major contributor to losses in poultry production. With emerging constraints on the use of in-feed prophylactic anticoccidial drugs and the relatively high costs of effective vaccines, there are commercial incentives to breed chickens with greater resistance to this important production disease. To identify phenotypic biomarkers that are associated with the production impacts of coccidiosis, and to assess their covariance and heritability, 942 Cobb500 commercial broilers were subjected to a defined challenge with Eimeria tenella (Houghton). Three traits were measured: weight gain (WG) during the period of infection, caecal lesion score (CLS) post mortem, and the level of a serum biomarker of intestinal inflammation, i.e. circulating interleukin 10 (IL-10), measured at the height of the infection.ResultsPhenotypic analysis of the challenged chicken cohort revealed a significant positive correlation between CLS and IL-10, with significant negative correlations of both these traits with WG. Eigenanalysis of phenotypic covariances between measured traits revealed three distinct eigenvectors. Trait weightings of the first eigenvector, (EV1, eigenvalue = 59%), were biologically interpreted as representing a response of birds that were susceptible to infection, with low WG, high CLS and high IL-10. Similarly, the second eigenvector represented infection resilience/resistance (EV2, 22%; high WG, low CLS and high IL-10), and the third eigenvector tolerance (EV3, 19%; high WG, high CLS and low IL-10), respectively. Genome-wide association studies (GWAS) identified two SNPs that were associated with WG at the suggestive level.ConclusionsEigenanalysis separated the phenotypic impact of a defined challenge with E. tenella on WG, caecal inflammation/pathology, and production of IL-10 into three major eigenvectors, indicating that the susceptibility-resistance axis is not a single continuous quantitative trait. The SNPs identified by the GWAS for body weight were located in close proximity to two genes that are involved in innate immunity (FAM96B and RRAD).

Immunomodulatory and ameliorative effects of Lactobacillus and Saccharomyces based probiotics on pathological effects of eimeriasis in broilers

Eimeria infection is very important in broilers and causes heavy economic losses in extensive farming system due to reduced weight gains, high mortality and poor feed conversion ratio (FCR). Under the circumstances, there is a dire need to devise effective control strategies to avoid/counteract this infectious threat. This study was conducted to assess the immunomodulatory and ameliorative effects of Lactobacillus and Saccharomyces based probiotics against Eimeria infection in broilers. The results showed statistically higher (P < 0.05) lymphoproliferative responses in experimental groups treated either with Lactobacillus or Saccharomyces based probiotics, as compared to control group. Further higher antibody titers (geomean titers) were also recorded in chickens of experimental groups treated with probiotics as compared to those of control group. The probiotic treated groups also revealed significantly improved (P < 0.05) FCRs as compared to control group. In challenge experiment, significantly lower (P < 0.05) oocyst counts were recorded in broilers treated with probiotics, when compared with control group. Further, experimental groups also revealed significantly higher (P < 0.05) daily weight gains and protection rates as compared to control. The data regarding the lesion scoring showed that chickens treated with probiotics had higher values of percent protection against intestinal and caecal lesion, when compared with those of control group. In conclusion, supplementation of probiotics proved very useful to enhance the immunological and performance potentials of broilers which subsequently provided protection against Eimeria infection. Further studies on the physico-chemical properties along with commercial feasibility and cost benefit analysis of these probiotic species are needed for wise selection to get maximum profit from broiler industry.

Effects of Eimeria tenella infection on chicken caecal microbiome diversity, exploring variation associated with severity of pathology.

Eimeria species cause the intestinal disease coccidiosis, most notably in poultry. While the direct impact of coccidiosis on animal health and welfare is clear, its influence on the enteric microbiota and by-stander effects on chicken health and production remains largely unknown, with the possible exception of Clostridium perfringens (necrotic enteritis). This study evaluated the composition and structure of the caecal microbiome in the presence or absence of a defined Eimeria tenella challenge infection in Cobb500 broiler chickens using 16S rRNA amplicon sequencing. The severity of clinical coccidiosis in individual chickens was quantified by caecal lesion scoring and microbial changes associated with different lesion scores identified. Following E. tenella infection the diversity of taxa within the caecal microbiome remained largely stable. However, infection induced significant changes in the abundance of some microbial taxa. The greatest changes were detected in birds displaying severe caecal pathology; taxa belonging to the order Enterobacteriaceae were increased, while taxa from Bacillales and Lactobacillales were decreased with the changes correlated with lesion severity. Significantly different profiles were also detected in infected birds which remained asymptomatic (lesion score 0), with taxa belonging to the genera Bacteroides decreased and Lactobacillus increased. Many differential taxa from the order Clostridiales were identified, with some increasing and others decreasing in abundance in Eimeria-infected animals. The results support the view that caecal microbiome dysbiosis associated with Eimeria infection contributes to disease pathology, and could be a target for intervention to mitigate the impact of coccidiosis on poultry productivity and welfare. This work highlights that E. tenella infection has a significant impact on the abundance of some caecal bacteria with notable differences detected between lesion score categories emphasising the importance of accounting for differences in caecal lesions when investigating the relationship between E. tenella and the poultry intestinal microbiome.

An optimized swine dysentery murine model to characterize shedding and clinical disease associated with \u201cBrachyspira hampsonii\u201d infection

BackgroundThe development of a mouse model as an in vivo pathogenicity screening tool for Brachyspira spp. has advanced the study of these economically important pathogens in recent years. However, none of the murine models published to date have been used to characterize the clinical signs of disease in mice, instead focusing on pathology following oral inoculation with various Brachyspira spp. The experiments described herein explore modifications of published models to characterize faecal consistency, faecal shedding and pathology in mice challenged with “Brachyspira hampsonii” clade II (Bhamp).Methods and resultsIn Experiment 1, 24 CF-1 mice were randomly allocated to one of three inoculation groups: sham (Ctrl), Bhamp, or B. hyodysenteriae (Bhyo; positive control). Half of each group was fed normal mouse chow (RMH) while the other received a low-zinc diet (TD85420). In Experiment 2, eight CF-1 mice and nine C3H/HeN mice were divided into Ctrl or Bhamp inoculation groups, and all fed TD85420. In Experiment 1, mice fed TD85420 demonstrated more severe mucoid faeces (P = 0.001; Kruskal Wallis) and faecal shedding for a significantly greater number of days (P = 0.005; Kruskal Wallis). Mean faecal scores of Bhamp inoculated mice trended higher than Ctrl (P = 0.06; Wilcoxon rank-sum) as did those of Bhyo mice (P = 0.0; Wilcoxon rank-sum). In Experiment 2, mean faecal scores of inoculated CF-1 mice were significantly greater than in C3H mice (P = 0.049; Kruskal Wallis) but no group differences in faecal shedding were observed. In both experiments, mice clustered based on the severity of colonic and caecal histopathology but high lesion scores were not always concurrent with high fecal scores.ConclusionIn our laboratory, CF-1 mice and the lower-zinc TD85420 diet provide a superior murine challenge model of “Brachyspira hampsonii” clade II.

High prevalence of Brachyspira spp. in layers kept in alternative husbandry systems associated with frequent species variations from end of rearing to slaughter

ABSTRACTA longitudinal survey was conducted to investigate the presence of Brachyspira species in layer flocks. A total of 66 layer flocks kept in alternative husbandry systems were sampled at three time points: end of rearing, at peak of lay and at end of lay. Content from caecal samples of freshly killed birds was cultured at each sampling time point and processed for further investigations. Gross pathological lesions in caeca were recorded during post mortem investigation. Spirochaetes were isolated from 50 flocks: three flocks were positive at all three sampling points, 25 flocks at two and 22 flocks at one sampling point, respectively. The presence of Brachyspira spp. could not be related to specific gross pathological caecal lesions or antibiotic treatments. The number of positive flocks increased with the age of birds. Furthermore, organic flocks were more often positive than flocks from barn systems. In total 80 spirochaetal cultures were obtained. B. intermedia (43.8%) was the most common species, followed by B. pulli (13.8%) and B. pilosicoli (12.5%). Brachyspira murdochii and B. innocens were found in 5.0% and 2.5%, respectively, whereas 11.3% of Brachyspira isolates could not be identified to species level. In 11.3% of the samples mixed infections were detected. Finally, the longitudinal survey revealed for the first time a possible shift in the Brachyspira species in a substantial number (32%) of layer flocks during their lifetime.

Comparative efficacy of various feed additives on the resistance of broilers to experimentally-induced caecal coccidiosis

Summary Coccidiosis is a parasitic disease of poultry that results in an increased morbidity and mortality. The resistance against coccidial drugs has urged the researchers to explore alternatives for disease control. Here, the effects of a prebiotic (Mannan-oligosaccharides), a probiotic mixture, neem ( Azadirachta indica) fruit powder and a commercial coccidiostat (diclazuril) were compared after coccidial infection in broiler chickens. A total of 250 day-old chicks were randomly divided into 5 treatment groups, which were fed on basal diet (control group), basal diet + 0.5% diclazuril (diclazuril group), basal diet + 0.1% probiotic (probiotic group), basal diet + 0.1% Mannan-oligosaccharides (prebiotic group) and basal diet + 0.3% neem fruit powder (neem group). on d 14 of the study, each bird was challenged with 10 4 viable sporulated E. tenella oocysts. The performance of broilers, oocyst per g (OPG) of faeces and caecal lesion score were determined.

The Infectivity of Exo and Endogenous Stages of Eimeria tenella in Broilers

Eimeria tenella is the most prevalent and pathogenic Coccidia causing morbidity, mortality and resulting in serious economic losses to the poultry industry worldwide. The aim of this study was to determine the immune response of broiler chickens to Eimeria tenella developmental stages Four hundred broilers divided into six groups (n=40) were used for the study. Each group was subdivided into two (n=20) as treated and non-treated and infected with different developmental stages (groups I-unsporulated oocysts, II-sporulated oocysts, III-schizonts, IV-merozoites and V-gametocytes respectively) of Eimeria tenella (local isolate), except group VI-control. The molecular identification of the local Eimeria tenella isolate identity was done through polymerase chain reaction (PCR) amplification of the genomic deoxyribonucleic acid (DNA). Clinical signs, gross caecal lesions, humoral and cellular-mediated immune response were determined in the infected broiler chickens with Eimeria tenella developmental stages. The faeces were processed using simple floatation technique and observed at 10x and 40x objectives of the Neiss microscope. Oocysts isolated from the caeca of birds naturally infected in Jos, Nigeria with the local strain were used to obtain the different developmental stages either in vitro or in vivo using bovine monocytes (schizonts), embryonated chicken eggs (gamatocytes) or two weeks old broilers (merozoites). To study the immune response elicited during the primary and secondary infection, each developmental stage was used to infect a group of two, three and half weeks old broilers, twenty of which were treated with the recommended dose of amprolium (250 mg/l (0.025%)) for 5 days at the appearance of clinical signs. At the tertiary infection, all the experimental birds except the control group of forty birds were orally infected with 105 sporulated oocysts of known characterized virulent Eimeria tenella strain. The mean oocysts output or count was 37.07 × 106 in the infected birds non-treated than 25.65 × 106 in the treated groups, although there was a gradual reduction (groups II–8.36 × 106–7.84 × 106–5.10 × 106; III-6.58 × 106–4.83 × 106; IV–7.18 × 106–7.00 × 106–3.83 × 106; V–6.59 × 106–5.87 × 106–4.20 × 106) in oocyst count from primary-secondary-tertiary infections except group I (control). There was a significant difference in oocyst output between the groups (II and IV) (p<0.05).

Immunization of Chicken with Live Eimeria tenella Sporulated Oocysts for Control of Caecal Coccidiosis

Eimeria tenella is the most pathogenic and one of the commonest species of Eimeria infecting broiler chickens raised under deep litter system throughout the world, causing caecal coccidiosis and incurring huge economic losses to the poultry industry. In the present study, the immunization potential of live Eimeria tenella oocysts was evaluated following homologous oocyst challenge in broilers. The birds were immunized at seven and 21 days of age orally with 1000 live sporulated oocyst of Eimeria tenella and challenged with homologous strain of parasite on 28 days of age. The immunization potential was evaluated in terms of relative weight gain, caecal lesion scoring, oocyst output and the anti-coccidial index (ACI). The results revealed that immunization with live oocysts of Eimeria tenella resulted in signifcant relative weight gain (82.47%), reduction in oocyst output (93.74%) and ACI of 161.47, indicating that oral immunization of chickens against E. tenella was effective in preventing the clinical disease and decreasing the oocyst burden in poultry farms.

PTU-009 Endoscopic Resection of Caecal Lesions ≥10 MM: Incomplete Resection and Complication Rate: Abstract PTU-009 Table 1

Introduction Endoscopic resection (ER) of caecal lesions remains technically challenging due to instability of the scope, bowel preparation and thinner bowel wall. Such limitations can affect completeness of ER. Currently there are very few data on endoscopic outcomes following ER of caecal lesions ≥10 mm. Our aim was to assess completeness and complication of ER. Methods Retrospective data was collected between 2011–2015 from documentation system ENDOBASE for all patients who had caecal ER. All lesions ≥10 mm were included. Morphology was categorised as per Paris classification. The following variables were recorded: lesion size and shape, type of ER (en bloc vs piecemeal), completeness of ER, histology, early complications, endoscopic follow up and remnant neoplasia on follow up. Results Mean (SD). A total of 111 caecal resections were performed. See table 1 for demographic details. Average lesion size was 17.2 (8.3) mm; Ip 15.0 (7.0), Is 14.7 (4.6), non-polypoid lesion 17.9 (8.8) mm. En bloc resection was achieved in 63%. In lesions Conclusion Remnant tissue post ER was similar to the UK national guidelines for colorectal polyps.1 Endoscopic resection of caecal lesions remains a challenge. Incomplete resection lesion invariably has remnant neoplasia on follow up. Strategies such as ESD/hybrid EMR should be considered. Reference 1 Rutter et al. doi:10.1136/gutjl-2015-309576 Disclosure of Interest None Declared

Evaluation of Kadaknath Chicken for Coccidial Resistance by Oocyst Count, Lesion Scoring and Oocyst Index inEimeria TenellaInfection

The aim of present investigation was to study the virulence of coccidiosis in Kadaknath birds, experimentally infected with E. tenella by OPG count, oocyst index and caecal lesions scoring. Sixty one-day old unsexed Kadaknath birds were randomly divided into a control, T1 and T2 groups comprising twenty chicks under each group. At d 21 of age, birds of T1 and T2 groups were individually inoculated with 10,000 and 20,000 of sporulated oocysts of E. tenella and from the d 5 to 9 pi, faecal droppings were collected for counting OPG. Also at d 4, 7 and 14 after E. tenella infection, 2 chicks from each challenge groups were euthanized and caecal lesions and oocyst index were scored. The results indicated that in both T1 and T2 challenge group, there was an increasing trend of OPG upto d 7 pi and the peak level of OPG was found at d 7 pi. Mean OPG was significantly (P<0.05) higher in T2 at d 6, 7 and 8 pi than T1. Mean caecal lesion score, oocyst index and OPG count were found to be maximum on d 7 pi for T1 and T2 groups. Lesions score was non significant at 4, 7 and 14 pi. However, oocyst index was significant (P<0.05) at d 7 pi. No mortality was observed in any of the treatment groups. As Kadaknath birds shed less oocyst and had lower lesion scores and oocyst index, hence, it can be concluded that this breed is less susceptible to coccidial infection.

Caecal-inoculation of entamoeba histolytica in the immunodepressed swiss albino mice treated with Cyclophosphamide

A total of 72 mice were used for an experimental model of intestinal amoebiasis developed in the Swiss albino mice dividing into three groups, experimental immunocompetent mice group (Group-A), experimental immunodepressed mice group (Group-B) and control group (Group-C). The inoculum (106 cells of Entamoeba histolytica/0.2 ml of medium) was used to inoculate into the caecum of the experimental groups of mice in the ICDDR,B laboratory, Dhaka. The mice were sacrificed at 5, 10, 15, 20, 25 and 30th days after inoculation for observation of caecal lesions and gross pathologic changes and histopathological analysis. The animals in the experimental two groups and control did not develop any caecal amoebiasis. The culture results of the stool of the mice which were inoculated with the inoculum of E. histolytica were found to be positive on the first 10 days after post caecal inoculation. After 10 days, the culture results were negative and the antiamoebic antibody levels of all animals were also found negative. DOI: http://dx.doi.org/10.3329/jbas.v38i2.21341 Journal of Bangladesh Academy of Sciences, Vol. 38, No. 2, 167-175, 2014

Incidence of single and mixed infections with Eimeria kofoidi, E. caucasica and E. legionensis on the health of experimentally infected red-legged partridges (Alectoris rufa)

Little is known about Eimeria-induced coccidiosis in partridges. After a coccidiosis outbreak in a farm rearing red-legged partridges (Alectoris rufa) in Brittany (France), three Eimeria species were identified as Eimeria kofoidi, Eimeria caucasica and Eimeria legionensis. This study aimed to reproduce the effects of the disease occurring in field conditions, in the absence of preventive treatments, to further build a coccidiosis model, helpful for coccidiostatic development. The pathogenic effects of a single infection with Eimeria kofoidi, E. caucasica and E. legionensis were evaluated, as well as the effects of multiple infections associating two or three of these species in red-legged partridges. Thirty-one-day-old birds were individually inoculated with Eimeria spp. and clinically followed up until 49 days of age. Mortality, lesion scores, daily oocyst production and growth were used as assessment criteria. Single infections with 250,000 E. kofoidi, 30,000 E. caucasica or 100,000 E. legionensis oocysts did not increase mortality rate compared to uninfected birds, whereas the combination of 3 species caused significant 28% mortality (P<0.05). Five days post inoculation, lesions scores in the proximal intestine (duodenum/jejunum) decreased in dual-infected birds and tended to decrease in triple-infected birds compared to lesions in mono-infected birds. The highest caecal lesion score was recorded in birds co-infected with E. kofoidi and E. legionensis. In multi-infected birds, the total number of oocysts excreted per gram of faeces was lower than the sum of oocysts excreted by mono-infected birds. Each single infection caused significant growth depression and even weight loss in E. legionensis infected birds (P<0.05). Dual or triple infections worsened this effect. Eighteen days post inoculation, only mono-infected birds had recovered. Their weight gains were not different from that of uninfected birds, whereas growth was significantly depressed in dual-infected birds, notably in co-infected E. kofoidi and E. legionensis birds and worsened in triple-infected birds (−34% and −78% growth depression, respectively). Our results indicate that the oocyst doses used were suitable in single infections or should be slightly reduced for future studies requiring significant growth retardation (about 25%). In mixed-infections, the effects on growth are considerably increased; therefore, oocyst doses must be reduced, approximately 125,000 E. kofoidi+15,000 E. caucasica+50,000 E. legionensis oocysts can be recommended. The study model presented here is valuable to conduct further research such as for assessing the ability of these birds to mount immune response against Eimeria spp. or for selecting efficient molecules to struggle coccidiosis of red-legged partridges.

Studies on Emblica officinalis derived tannins for their immunostimulatory and protective activities against coccidiosis in industrial broiler chickens.

The present study reports the effect of Emblica officinalis (EO) derived tannins on humoral immune responses and their protective efficacy against Eimeria infection in chickens. Tannins were extracted from EO and characterized by HPLC. EO derived tannins (EOT) and commercial tannins (CT) were orally administered in broiler chicks in graded doses for three consecutive days, that is, 5th-7th days of age. On day 14 after administration of tannins, humoral immune response was detected against sheep red blood cells (SRBCs) by haemagglutination assay. Protective efficacy of tannins was measured against coccidial infection, induced by Eimeria species. Results revealed higher geomean titers against SRBCs in chickens administered with EOT as compared to those administered with CT and control group. Mean oocysts per gram of droppings were significantly lower (P < 0.05) in EOT administered chickens as compared to control group. Lesion scoring also showed the lowest caecal and intestinal lesion score of mild to moderate intensity in chickens administered with EOT. Further, significantly higher (P < 0.05) daily body weight gains and antibody titers were detected in EOT administered chickens as compared to those of CT administered and control groups. EOT showed the immunostimulatory properties in broilers and their administration in chickens boost the protective immunity against coccidiosis.

An Eimeria vaccine candidate based on Eimeria tenella immune mapped protein 1 and the TLR-5 agonist Salmonella typhimurium FliC flagellin

Immune mapped protein-1 (IMP1) is a new protective protein in apicomplexan parasites, and exits in Eimeria tenella. But its structure and immunogenicity in E. tenella are still unknown. In this study, IMPI in E. tenella was predicted to be a membrane protein. To evaluate immunogenicity of IMPI in E. tenella, a chimeric subunit vaccine consisting of E. tenella IMP1 (EtIMP1) and a molecular adjuvant (a truncated flagellin, FliC) was constructed and over-expressed in Escherichia coli and its efficacy against E. tenella infection was evaluated. Three-week-old AA broiler chickens were vaccinated with the recombinant EtIMP1-truncated FliC without adjuvant or EtIMP1 with Freund’s Complete Adjuvant. Immunization of chickens with the recombinant EtIMP1-truncated FliC fusion protein resulted in stronger cellular immune responses than immunization with only recombinant EtIMP1 with adjuvant. The clinical effect of the EtIMP1-truncated FliC without adjuvant was also greater than that of the EtIMP1 with adjuvant, which was evidenced by the differences between the two groups in body weight gain, oocyst output and caecal lesions of E. tenella-challenged chickens. The results suggested that the EtIMP1-flagellin fusion protein can be used as an effective immunogen in the development of subunit vaccines against Eimeria infection. This is the first demonstration of antigen-specific protective immunity against avian coccidiosis using a recombinant flagellin as an apicomplexan parasite vaccine adjuvant in chickens.

Anticoccidial effects of a novel triazine nitromezuril in broiler chickens

The anticoccidial efficacy of 2-(3-methyl-4-(4-nitrophenoxy)phenyl)-1,2,4-triazine-3,5(2H,4H)-dione (nitromezuril, NZL), a novel triazine compound, was evaluated in three different studies under experimental conditions. The anticoccidial efficacy was chiefly evaluated using the anticoccidial index (ACI). The resistance level was determined by calculating ACI, percentage optimum anticoccidial activity (POAA), reduction in lesion scores (RLS) and relative oocyst production (ROP). In the dose determination study (study A), NZL was added to the diet at doses of 1, 2, 3, 4, 5 and 6mg/kg to test its efficacy against coccidiosis caused by Eimeria tenella. Groups treated with NZL 1mg/kg feed could observe the faecal dropping scores and caecal lesions. ACIs of NZL-treated groups reached 179–199. In the study on the anticoccidial efficacy of 3mg/kg NZL in the diet (study B), only a few faecal oocysts and slight lesions were observed. NZL significantly promoted weight gain (WG) and reduced lesion scores (LS) compared to controls receiving diclazuril (DZL) (P<0.05). ACIs of NZL-treated groups were 193, 192, 191 and 163 for E. tenella, Eimeria necatrix, Eimeria acervulina and Eimeria maxima, respectively, whereas those of DZL-treated groups were 185, 176, 176 and 148. In the cross-drug resistance study (study C), ACIs of NZL and toltrazuril (TZL)-treated groups ranged from 188 to 204, which were significantly higher than those of DZL-treated groups (P<0.05). NZL- and TZL-treated groups were sensitive to experimentally induced DZL-resistant E. tenella, whereas DZL-treated groups showed complete resistance. No cross-resistance was observed between DZL and NZL or TZL. Based on the abovementioned studies, it was concluded that diets containing 3mg/kg NZL had an excellent efficacy in preventing coccidiosis in broiler chickens. The activity of 3mg/kg NZL in the diet was equal or superior to that of 1mg/kg DZL. These results are of great significance for the future applications of NZL; however, its actual mechanism of action remains unknown. NZL is a potential novel anticoccidial agent suitable for further development.

Intracloacally passaged low-virulent Histomonas meleagridis protects turkeys from histomonosis

Histomonosis (blackhead disease or infectious enterohepatitis) caused by the extracellular protozoon parasite Histomonas meleagridis is an important disease of turkeys and a threat to the poultry industry. Due to recent legislation on drug restrictions, research to find new alternatives is an urgent matter in the battle against histomonosis. In the present study, intracloacal inoculation of a low-virulent H. meleagridis strain isolated after serial passages in turkeys clearly demonstrated a reduction of virulence and hence its effectiveness as a vaccine against histomonosis. The low-virulent isolate has been evaluated in a comparative experimental infection study. No mortality nor predominant caecal or liver lesions could be observed in the groups inoculated with 103, 104 or 105 histomonads per bird. Only dilated caeca with a yellow and foamy content could be noticed. Groups inoculated with similar doses of a virulent strain displayed a dose-related pathology and mortality up to 100%. The protective capacity of the strain with reduced virulence could be demonstrated as none of the birds cloacally inoculated with 103, 104 or 105 histomonads died upon challenge with 105H. meleagridis of the virulent strain. Hereby, 71% of the challenge control group died. Interestingly, no or only very minor pathological lesions in the caeca and liver could be detected after challenge of the birds inoculated with the passaged histomonads. In conclusion, cloacal inoculation of the low-virulent strain obtained after serial backpassages was able to induce protection of turkeys against challenge with a virulent H. meleagridis strain.