Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 888
Filtrar
1.
Vet Parasitol ; 277: 108967, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31812121

RESUMO

Neospora caninum infection is regarded as one of the most important infectious causes of abortion in dairy cattle. To intervene in its spread, four potential controls including test-and-cull, medication, vaccination, and selective breeding are considered and assessed in this study. The cost of each control, together with the inevitable annual loss due to population dynamics, is adopted as an assessment criterion from an economic point of view. By performing simulation and sensitivity analysis, our results demonstrate that compared with each single control, combined controls are worthwhile with better financial outcomes. For farm affected with significant prevalence (equal to or greater than 30%), vaccine treatment is the most effective and economical option among all control strategies. On the other hand, for farm where prevalence is relatively low (around 10%), combined control, by applying vaccination followed with test-and-cull, medication or selective breeding, could be alternative treatment to provide better financial outcome against single control in an observed period.


Assuntos
Doenças dos Bovinos/prevenção & controle , Doenças dos Bovinos/terapia , Coccidiose/veterinária , Terapia Combinada/veterinária , Animais , Antiparasitários/uso terapêutico , Cruzamento , Bovinos , Doenças dos Bovinos/economia , Coccidiose/economia , Coccidiose/prevenção & controle , Coccidiose/terapia , Indústria de Laticínios/economia , Neospora/fisiologia , Dinâmica Populacional , Vacinas Protozoárias
2.
Parasitol Res ; 118(11): 3173-3183, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31606835

RESUMO

Prevention of coccidiosis is one of the best ways of controlling disease. Therefore, the present study was carried out to evaluate the protective effect of ultraviolet (UV)-irradiated sporulated oocysts of Eimeria species against coccidiosis in layer chickens. One hundred forty-four one-day-old layer chicks were randomly divided into 4 groups (n = 36), including non-immunized/non-challenged negative control group (NC group), non-immunized/challenged control group (NIC group), non-irradiated sporulated oocyst/challenged group (CA group), and UV-irradiated sporulated oocyst/challenged (UV group). At the age of 4 days, chickens in groups UV and CA were both orally inoculated with 1.0 × 104 UV-irradiated and non-irradiated sporulated oocysts of Eimeria species, respectively. Chickens in groups NIC and NC were served as positive and negative controls, respectively. Chickens in all groups were orally challenged with 7.5 × 104 sporulated oocysts of Eimeria species except the NC group at the age of 21 days. The results revealed that chicks receiving UV-irradiated sporulated oocysts had no signs of illness with minimal or no changes in the cecal integrity and a significantly lower oocyst shedding (OPG) than in the NIC group. Additionally, the cytokine gene expression profiles were evaluated. Expression levels of IL-2, IL-12, and IFN-γ were significantly higher in the spleen of chicks in the UV and CA groups than in the NC group post-challenge. As expected, treatment with irradiated oocysts resulted in a significant reduction in oocyst shedding and maintenance of cecal mucosal integrity. Furthermore, the body weight was higher in chickens inoculated with UV-irradiated oocysts than their non-irradiated counterparts. In conclusion, our results demonstrate that inoculation with UV-irradiated sporulated oocysts of Eimeria species can produce a substantial reduction in infection symptoms.


Assuntos
Galinhas , Coccidiose/veterinária , Eimeria , Oocistos/imunologia , Doenças das Aves Domésticas/prevenção & controle , Vacinas Protozoárias/administração & dosagem , Animais , Peso Corporal , Coccidiose/prevenção & controle , Eimeria/imunologia , Eimeria/efeitos da radiação , Masculino , Oocistos/efeitos da radiação , Doenças das Aves Domésticas/parasitologia , Raios Ultravioleta , Vacinação/veterinária
3.
Vet Parasitol ; 273: 105-111, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31473449

RESUMO

Diclazuril, which is widely used for the prevention of coccidiosis in chickens, has a lethal effect on asexual and sexual stages of Eimeria spp. However, little is known about its effect on the exogenous stages of Eimeria spp. In this study, we evaluated the effect of in vitro treatment with 0.2% diclazuril on unsporulated and sporulated oocysts of Eimeria spp. For this purpose, a total of 180 male layer chicks aged one day were randomly divided into 5 experimental groups. Each group was divided into 3 replicates of 12 chicks each. Group 1 (G1) and Group 2 (G2) were negative (non-immunized and non-challenged) and positive (non-immunized and challenged) controls, respectively. Group 3 (G3) was immunized per os with 1.0 × 104 non-diclazuril treated-sporulated oocysts. Groups 4 (G4) was immunized per os with 0.2% diclazuril treated-unsporulated oocysts (1.0 × 104) in which diclazzuril didn't affect sporulation. Group 5 (G5) was immunized per os with 0.2% diclazuril treated-sporulated oocysts (1.0 × 104). Chicks of G2, G3, G4, and G5 were challenged with 7.5 × 104 untreated sporulated oocysts at the age of 21 days, while the group 1 chicks remained unchallenged. G4 and G5 animals immunized with 0.2% diclazuril-treated oocysts showed a significant decrease in bloody diarrhea severity, lesion scores, and oocyst counts in comparison to those immunized with untreated oocysts. Furthermore, histopathologic findings showed a low number of parasitic stages in cecal tissues in G4 and G5. A significant increased body weight gain was observed in Gs 4 and 5 in comparison to G2. In addition, expression levels of IL-2, IL-12, and IFN-γ were significantly increased in G4 and G5. In conclusion, diclazuril is effective in attenuating Eimeria oocysts and thus provides an alternative approach for using diclazuril-treated oocysts to protect chicks against Eimeria challenge.


Assuntos
Coccidiose/veterinária , Eimeria/efeitos dos fármacos , Nitrilos/farmacologia , Oocistos/efeitos dos fármacos , Doenças das Aves Domésticas , Triazinas/farmacologia , Animais , Ceco/parasitologia , Galinhas , Coccidiose/parasitologia , Coccidiose/prevenção & controle , Eimeria/patogenicidade , Masculino , Doenças das Aves Domésticas/parasitologia , Doenças das Aves Domésticas/prevenção & controle , Distribuição Aleatória , Virulência/efeitos dos fármacos
4.
Parasitol Res ; 118(10): 3033-3041, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31407118

RESUMO

Coccidiosis, caused by the infection of Eimeria parasites, is one of the most common diseases in domestic rabbits. Live anticoccidial vaccine formulated with attenuated precocious lines of pathogenic eimerian parasites is expected to be valuable for the control of rabbit coccidiosis as a similar strategy to produce anticoccidial vaccines against chicken coccidiosis has being used for several decades. Eimeria media, moderate pathogenic, is widespread in China. Therefore, attenuated anticoccidial vaccines against rabbit coccidiosis should contain vaccine strain(s) of E. media. In this study, a precocious line of E. media (Empre) was selected by collecting and propagating the early excreted oocysts with 16 successive generations. The prepatent period of Empre reduced from 108 h of its parental strain (Emwt) to 70 h. The fecundity of Empre was about 1/10 to 1/3 lower than that of Emwt. Each sporocyst of Empre sporulated oocyst contained only one large refractile body instead of two smaller ones seen in the parental strain. When vaccinated with 1 × 103 or 1 × 104 precocious line oocysts, the rabbits were completely protected against homologous challenge with the parental strain 14 days post challenge by terms of body weight gain and oocyst output counting, indicating the efficacy of Empre. Meanwhile, all immunized rabbits showed no clinical sign post immunization, indicating the safety of Empre. For co-immunization, 1 × 103Empre oocysts and 5 × 102 oocysts of a precocious line of E. intestinalis (EIP8) were inoculated to each rabbit in a trial. No diarrhea or mortality was found after vaccination, and the weight gains of the vaccinated group were similar to that of unvaccinated-unchallenged control (UUC) group, while the weight gains of the vaccinated group were similar to that of unvaccinated-unchallenged control (UUC) group (P > 0.05), but significantly higher than that of UCC group (P < 0.01) after challenge, indicating it is safe and effective when using co-immunization. These results together show that Empre, as a precocious line, is a good candidate of precocious line of E. media for anticoccidial vaccine development.


Assuntos
Coccidiose/veterinária , Eimeria/patogenicidade , Infecções Protozoárias em Animais/parasitologia , Animais , Coccidiose/parasitologia , Coccidiose/prevenção & controle , Eimeria/crescimento & desenvolvimento , Eimeria/imunologia , Eimeria/fisiologia , Imunização/veterinária , Oocistos/crescimento & desenvolvimento , Oocistos/imunologia , Oocistos/patogenicidade , Infecções Protozoárias em Animais/prevenção & controle , Vacinas Protozoárias/imunologia , Coelhos , Reprodução , Vacinas Atenuadas/imunologia
5.
Acta Trop ; 198: 105094, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31323195

RESUMO

Neospora caninum is the etiological agent of neosporosis, a worldwide infectious disease recognized as the major cause of abortions and reproductive failures in livestock, responsible for significant economic losses in cattle industries. Currently, there are not cost-effective control options for this pathology, and the development of a vaccine involving new and integrated approaches is highly recommended. In this study, we evaluated the immunogenic and protective efficacy, as well as the potential DIVA (Differentiation of Infected from Vaccinated Animals) character of a recombinant subunit vaccine composed by the major surface antigen from N. caninum (NcSAG1) and the carrier/adjuvant heat shock protein 81.2 from Arabidopsis thaliana (AtHsp81.2) in a mouse model of congenital neosporosis. BALB/c female mice were intraperitoneal (i.p.) immunized with a mixture of equimolar quantities of rNcSAG1 and rAtHSP81.2 or each protein alone (rNcSAG1 or rAtHsp81.2). The vaccine containing a mixture of rNcSAG1 and rAtHsp81.2 significantly enhanced the production of specific anti-rNcSAG1 total IgG (tIgG), IgG1 and IgG2a antibodies in immunized mice when compared to control groups (non-vaccinated and rAtHsp81.2 immunized mice) as well as to the group of mice immunized only with the antigen (rNcSAG1). In addition, partial protection against vertical transmission and improvement of the offspring survival time was observed in this group. On the other hand, rAtHsp81.2 induced the production of specific anti-rAtHsp81.2 tIgG, allowing us to differentiate vaccinated from infected mice. Despite further experiments have to be made in cattle to test the capability of this vaccine formulation to differentiate vaccinated from infected animals in the field, our results suggest that the formulation composed by rNcSAG1 and rAtHsp81.2 could serve as a basis for the development of a new vaccine approach against bovine neosporosis.


Assuntos
Antígenos de Protozoários/imunologia , Coccidiose/prevenção & controle , Transmissão Vertical de Doença Infecciosa/prevenção & controle , Complicações Parasitárias na Gravidez/prevenção & controle , Vacinas Protozoárias/imunologia , Animais , Anticorpos Antiprotozoários , Coccidiose/parasitologia , Feminino , Imunoglobulina G , Camundongos , Camundongos Endogâmicos BALB C , Neospora/imunologia , Gravidez , Vacinação , Vacinas Sintéticas/imunologia
6.
Parasit Vectors ; 12(1): 347, 2019 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-31300007

RESUMO

BACKGROUND: Live anticoccidial vaccines have been a tremendous success for disease prevention. The establishment of the reverse genetic manipulation platform has enabled the development of Eimeria parasites, the live anticoccidial vaccine strains, as vaccine vectors. In our previous study, recombinant E. tenella expressing a single immunodominant antigen of E. maxima (Et-EmIMP1) was able to protect chickens against challenge infection with E. maxima. This promising result encouraged us to further explore strategies to improve the protection efficacy of recombinant Eimeria and develop it as a vaccine vector. RESULTS: We constructed a novel recombinant Eimeria line expressing apical membrane antigen 1 of E. maxima (Et-EmAMA1) and then immunized chickens with Et-EmAMA1 and/or Et-EmIMP1. We found that the E. maxima soluble antigen-specific cell-mediated immunity was much stronger in the birds that were co-immunized with Et-EmAMA1 and Et-EmIMP1 than in those that were immunized with Et-EmAMA1 or Et-EmIMP1 alone. The oocyst production after E. maxima infection was significantly reduced in the recombinant Eimeria-immunized birds compared with the wild-type-immunized and naïve birds. The oocyst production in the birds co-immunized with Et-EmAMA1 and Et-EmIMP1 was consistently the lowest among the treatment groups after E. maxima infection. CONCLUSIONS: These results demonstrated that Eimeria is an effective vaccine vector that can carry and deliver heterologous Eimeria antigens to the host immune system and trigger specific immune responses. Our results also suggested that increasing the number of recombinant Eimeria lines is an effective approach to enhance protective immunity against infections with heterologous pathogens.


Assuntos
Coccidiose/veterinária , Eimeria tenella/genética , Eimeria/genética , Imunidade Celular , Doenças das Aves Domésticas/prevenção & controle , Vacinas Protozoárias/imunologia , Animais , Antígenos de Protozoários/imunologia , Galinhas , Coccidiose/prevenção & controle , Eimeria/imunologia , Eimeria tenella/imunologia , Doenças das Aves Domésticas/imunologia , Organismos Livres de Patógenos Específicos , Vacinas Atenuadas , Vacinas Sintéticas
7.
Poult Sci ; 98(10): 4480-4491, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31149727

RESUMO

Avian coccidiosis caused by Eimeria inflicts high economic losses to the poultry industry. Application of drugs and live vaccines presents particular challenges in pathogen resistance and cost, hence alternative anti-coccidial strategies are needed. In this study, peptides that specifically bind E. tenella AMA1 (EtAMA1) were screened from a phage display peptide library. The positive clones of target phages were characterized by ELISA after four rounds of biopanning. The binding capabilities with EtAMA1 and sporozoite proteins for the two selected peptides were detected by ELISA. The role of the two target peptides in inhibiting sporozoite invasion of MDBK cells was evaluated in vitro and the anti-coccidial effects of the two phages were assessed by an animal experiment. The three-dimensional (3D) structural model of EtAMA1 extracellular domain (EctoAMA1) protein was constructed based on the crystal template of TgAMA1 (PDB ID: 2 × 2Z), and the molecular docking between target peptides and EctoAMA1 model was analyzed. The results showed that two selected phages strongly interacted with EctoAMA1 and sporozoites protein. Two corresponding specific EtAMA1-binding peptide (named L and C) showed significant effects on inhibiting sporozoite invasion of MDBK cells. Chickens orally fed the two target phages showed partial protection against homologous challenge. Homology modeling analysis showed an apical hydrophobic groove was shaped on the top of the EctoAMA1 model. Molecular docking indicated the interaction between the EctoAMA1 protein and the two peptides, which was mainly reflected by the hydrophobic interaction and formation of intermolecular hydrogen bond. The above results suggest that the peptides L and C, especially L peptide, competed with E. tenella rhotry neck protein 2 (EtRON2) for binding to EtAMA1 located on the surface of sporozoites, and therefore inhibited the parasite invasion into cells.


Assuntos
Galinhas , Coccidiose/veterinária , Eimeria tenella/fisiologia , Doenças das Aves Domésticas/prevenção & controle , Animais , Coccidiose/prevenção & controle , Simulação de Acoplamento Molecular , Proteínas de Protozoários/fisiologia , Distribuição Aleatória , Esporozoítos/fisiologia
8.
Parasitol Res ; 118(7): 2009-2026, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31152233

RESUMO

Coccidiosis is a parasitic disease of a wide variety of animals caused by coccidian protozoa. The coccidia are responsible for major economic losses of the livestock industry. For example, the annual cost due to coccidiosis to the global poultry industry has been estimated to exceed US$ 3 billion annually. Currently available drugs for the control of this disease are either polyether ionophorous antibiotics that are derived from fermentation products, or synthetic compounds, produced by chemical synthesis. Unfortunately, no new drugs in either category have been approved for use for decades. Resistance has been documented for all those of the drugs currently employed and therefore the discovery of novel drugs with unique modes of action is imperative if chemotherapy is to remain the principal means to control this disease. This chapter aims to give an overview of the efficacy and mode of action of the current compounds used to control coccidiosis in livestock and provides a brief outlook of research needs for the future.


Assuntos
Coccídios/efeitos dos fármacos , Coccidiose/veterinária , Coccidiostáticos/farmacologia , Gado/parasitologia , Doenças das Aves Domésticas/prevenção & controle , Animais , Coccidiose/prevenção & controle , Aves Domésticas , Doenças das Aves Domésticas/parasitologia
9.
Parasitol Res ; 118(6): 1701-1710, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31065831

RESUMO

Coccidiosis is a major poultry disease which compromises animal welfare and costs the global chicken industry a huge economic loss. As a result, research entailing coccidial control measures is crucial. Coccidiosis is caused by Eimeria parasites that are highly immunogenic. Consequently, a low dosage of the Eimeria parasite supplied by a vaccine will enable the host organism to develop an innate immune response towards the pathogen. The production of traditional live anticoccidial vaccines is limited by their low reproductive index and high production costs, among other factors. Recombinant vaccines overcome these limitations by eliciting undesired contaminants and prevent the reversal of toxoids back to their original toxigenic form. Recombinant vaccines are produced using defined Eimeria antigens and harmless adjuvants. Thus, studies regarding the identification of potent novel Eimeria antigens which stimulate both cell-mediated and humoral immune responses in chickens are essential. Although the prevalence and risk posed by Eimeria have been well established, there is a dearth of information on genetic and antigenic diversity within the field. Therefore, this paper discusses the potential and efficiency of recombinant vaccines as an anticoccidial control measure. Novel protective Eimeria antigens and their antigenic diversity for the production of cheap, easily accessible recombinant vaccines are also reviewed.


Assuntos
Coccidiose/veterinária , Eimeria/imunologia , Doenças das Aves Domésticas/prevenção & controle , Vacinas Protozoárias/imunologia , Adjuvantes Imunológicos , Animais , Antígenos/administração & dosagem , Antígenos/genética , Antígenos/imunologia , Galinhas/parasitologia , Coccidiose/imunologia , Coccidiose/parasitologia , Coccidiose/prevenção & controle , Eimeria/genética , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/parasitologia , Vacinas Protozoárias/administração & dosagem , Vacinas Protozoárias/genética
10.
Poult Sci ; 98(10): 4901-4908, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31064006

RESUMO

Feed additives that promote gastrointestinal health may complement coccidiosis vaccination programs in antibiotic-free broiler production systems. This study examined the effects of a commercial feed additive blend (FA) on intestinal histomorphology and inflammatory biomarkers in vaccinated Ross 708 cockerels (N = 2,160). The study was a randomized complete block design (12 blocks) with 3 dietary treatments: CON (negative control), AGP (positive control: 55 ppm of bacitracin methylene disalicylate), and FA (1.5 kg/MT in starter; 1.0 kg/MT in grower; and 0.5 kg/MT in finisher). Birds were reared on re-used litter and fed a 3-phase feeding program (starter, 0 to 14 D; grower, 15 to 28 D; finisher, 29 to 36 D). One master batch of basal feed for each feeding phase was prepared and final experimental diets were manufactured by mixing the basal feed with the respective test ingredient prior to pelleting. Growth measurements, including pen body weight and feed intakes, and fresh fecal samples were taken throughout the study. On day 20, samples of intestinal tissue were collected from a subset of birds (n = 72, 1 block) for histomorphology and mRNA expression of tight junction and inflammatory genes. In the duodenum, the ratio of villi length to crypt depth was significantly lower in FA (and AGP) fed birds than those consuming the CON diet. Relative mRNA expressions of iNOS, IFNƔ, and claudin-1 were upregulated in the jejunum of FA and AGP treatment groups compared to those in the CON group; the response in the FA was of lesser magnitude than AGP. Together, these results demonstrated that the FA treatment altered the microstructure of the duodenum and affected the expression of inflammatory genes in the jejunum. The timing of these changes coincided with peak oocyte shedding in feces and an observed reduction in feed efficiency in all dietary treatment groups.


Assuntos
Galinhas/fisiologia , Ácidos Graxos/metabolismo , Expressão Gênica/efeitos dos fármacos , Intestinos/efeitos dos fármacos , Compostos Fitoquímicos/metabolismo , Ração Animal/análise , Animais , Coccidiose/parasitologia , Coccidiose/prevenção & controle , Coccidiose/veterinária , Dieta/veterinária , Ácidos Graxos/administração & dosagem , Expressão Gênica/imunologia , Intestinos/anatomia & histologia , Intestinos/fisiologia , Compostos Fitoquímicos/administração & dosagem , Doenças das Aves Domésticas/parasitologia , Doenças das Aves Domésticas/prevenção & controle , Distribuição Aleatória , Vacinação/veterinária
11.
Poult Sci ; 98(10): 4878-4888, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31064007

RESUMO

An experiment was conducted to evaluate broilers vaccinated against coccidiosis fed combinations of pre-starter and starter diets varying in digestible amino acid (dAA) density from 1 to 19 d of age on subsequent growth performance and meat yield. A total of 1,800 Yield Plus Ross × Ross 708 male broilers were allocated to 60 floor pens and assigned to 1 of the 6 treatments. Four pre-starter diets varying in dAA density [1.15% dLys, 1.25% dLys, 1.35% dLys, and Positive Control (1.15% dLys + Diclazuril)] were fed until 9 d of age. Then, 3 starter diets varying in dAA density [1.15% dLys, 1.25% dLys, and PC (1.15% dLys + Diclazuril)] were given from 10 to 19 d of age. All diets were formulated to similar dAA ratios to dLys; hence, resulting in increasing amino acid (AA) density among the dietary treatments. Birds were given common grower and finisher diets for the remainder of the experiment. At 19, 27, and 40 d of age, broilers that received the 1.35% and 1.25% dLys density pre-starter and 1.25% dLys density starter diets had increased BW gain (P ≤ 0.006) compared with broilers fed the 1.15% dLys density diets. Broilers that received the 1.15% dLys density pre-starter diet had a lower cumulative BW gain (P = 0.007) than those fed the 1.35% and 1.25% dLys density pre-starter diets. Broilers that received the 1.35% and 1.25% dLys density pre-starter and 1.25% dLys density starter diets had the heaviest (P ≤ 0.008) total breast weights. Increasing the pre-starter dAA density enhanced (P ≤ 0.03) total breast weight by 28 g (1.25% dLys density) and 51 g (1.35% dLys density). Results from this study indicated that increasing dAA density from 1 to 19 d of age enabled a 1 to 19 d dAA intake increase of 4.8 g, which enhanced cumulative growth and meat yield of broilers vaccinated against coccidiosis.


Assuntos
Aminoácidos/metabolismo , Galinhas/fisiologia , Dieta/veterinária , Carne/análise , Aminoácidos/administração & dosagem , Ração Animal/análise , Animais , Galinhas/imunologia , Coccidiose/prevenção & controle , Relação Dose-Resposta a Droga , Masculino , Distribuição Aleatória , Vacinação/veterinária
12.
Poult Sci ; 98(8): 3176-3180, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-30953077

RESUMO

The purpose of this study was to determine if Eimeria oocysts recovered from litter at the time of chick placement in commercial broiler houses contained oocysts that were infectious for chickens. Over 100 litter samples were collected from 30 poultry farms representing a total of 60 different broiler houses with 9 houses sampled more than once over 1.5 yr. The samples were collected just before the placement of newly hatched chicks and after an anticoccidial drug (ACD) or Eimeria vaccine (VAC) program, and processed for counting oocysts followed by Eimeria species determination using ITS1 PCR. Broiler chicks were inoculated with recovered Eimeria oocysts to determine if the litter oocysts were viable and capable of causing patent infection. At placement, E. maxima (Emax) oocysts were detected in 70 of 75 houses after ACD program and 46 of 47 houses after VAC program. Eimeria acervulina, E. praecox, and/or E. tenella (Eapt) were detected in 75 of 75 houses after ACD program and 47 of 47 houses after VAC program. Viability testing revealed that 33.0% of broiler houses contained viable Emax oocysts, while 46.9% contained viable Eapt oocysts. During VAC programs, the concentration of Emax oocysts at placement and the total number of Emax oocysts shed by chickens in viability studies showed a very strong correlation (r = 0.83). Likewise, during ACD programs, the concentration of Eapt oocysts at placement and the total number of Eapt oocysts shed by chickens in the viability study showed a strong correlation (r = 0.62). In general, Eimeria oocyst levels at placement and number of viable oocysts shed by chickens in the viability study were similar among houses on the same farm. However, the number of Eimeria oocysts shed in the viability studies was considerably less than expected based on the number of oocysts given. These data suggest that nearly 100% of all poultry houses contain Emax and Eapt oocysts at placement with 30 to 50% of the houses containing viable Eimeria oocysts, thus possibly representing a source of the protozoa to newly hatched chicks.


Assuntos
Coccidiose/veterinária , Eimeria/isolamento & purificação , Oocistos/isolamento & purificação , Doenças das Aves Domésticas/transmissão , Animais , Animais Recém-Nascidos , Galinhas , Coccidiose/prevenção & controle , Coccidiose/transmissão , Coccidiostáticos/administração & dosagem , Abrigo para Animais , Doenças das Aves Domésticas/parasitologia , Doenças das Aves Domésticas/prevenção & controle , Vacinas Protozoárias/administração & dosagem , Vacinação/veterinária
13.
Poult Sci ; 98(10): 4815-4828, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-30995312

RESUMO

High dietary protein and the use of poorly digested protein sources have been suggested to negatively impact broiler health, possibly because of protein fermentation in the distal intestinal tract. The effect of dietary protein levels with low or high indigestible protein fractions (LIP or HIP) on male and female broiler performance were evaluated. The trial was completely randomized with a 2 × 3 × 2 factorial arrangement, where gender, dietary protein levels (24, 26, and 28%), and dietary protein digestible fractions were the main factors. Ross 308 male (1944) and female (2232) were allocated to 72 pens with 54 males or 62 females per pen. Six grower diets 24-LIP, 24-HIP, 26-LIP, 26-HIP, 28-LIP, and 28-HIP were fed from 0 to 32 D of age. Birds were vaccinated with Coccivac-B52 on day 5, and feed intake and BW were recorded on 0, 12, 22, and 32 D. On day 32, 24 birds per treatment were processed for meat yield. Males were heavier than females at all post-hatch ages and the LIP birds were heavier than their HIP counterparts on 32 D. On day 22, birds fed 24 and 26% CP were heavier than those fed 28% CP. Birds fed the 28-LIP diet consumed less total feed than their 24 and 26-LIP equivalents. Birds fed 24% CP had the highest total feed to gain ratio, whereas LIP fed birds had a lower total feed to gain than those fed HIP diets. LIP diets resulted in higher total mortality than the HIP diets. Carcass yield was higher for females than males, increased with CP level, and was lower in HIP than LIP birds. An interaction between CP level and protein digestibility resulted in the 26 and 28-LIP having higher breast yield than all other diets. In conclusion, broiler growth performance and meat yield were affected by dietary indigestible protein alone or in combination with gender and dietary CP level.


Assuntos
Galinhas/metabolismo , Coccidiose/prevenção & controle , Proteínas na Dieta/metabolismo , Carne/análise , Vacinação/veterinária , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal/efeitos dos fármacos , Animais , Dieta/veterinária , Proteínas na Dieta/administração & dosagem , Digestão/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Masculino , Distribuição Aleatória
14.
Poult Sci ; 98(7): 2800-2812, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30877749

RESUMO

The objective of this study was to evaluate performance, diversity, composition, and predicted function of the intestinal microbiota of broilers raised under 3 different methods to induce necrotic enteritis (NE). The chicks in Experiments 1 and 2 were vaccinated against coccidiosis on day 1. Experiment 1: non-challenged and challenged birds were raised in floor pens with new litter and 58 birds/pen. The challenge consisted of Eimeria maxima inoculation on day 14 and Clostridium perfringens via water on days 18 to 19. Cecal microbiota was evaluated on days 18, 21, and 28. Experiment 2: non-challenged and challenged birds were raised in floor pens with recycled litter and 50 birds/pen. The challenge consisted of C. perfringens via feed from days 18 to 20. Ileal and cecal microbiota were evaluated on day 21. In Experiment 3, non-challenged and challenged birds were raised in battery cages with 8 birds/cage. Challenged birds were inoculated with E. maxima on day 14 and with C. perfringens on days 19 to 21. In the 3 experiments, ileal or cecal microbiota or both were analyzed through 16S rRNA sequencing. The performance of the birds was impaired in the 3 studies, regardless of the method used to induce NE. In Experiment 1, the microbiota did not significantly change across ages. In Experiment 2, α-diversity indices were lower in challenged vs. non-challenged birds in both ileal and cecal microbiota. The cecal microbiota composition and function was more affected than the ileal microbiota. In Experiment 3, Chao index (α-diversity) increased in challenged vs. non-challenged birds, and the composition of the ileal and cecal microbiota was not significantly affected. In conclusion, the overall feed conversion ratio was more affected in Experiment 3 (5.2, 11.1, and 30% for Experiments 1, 2, and 3, respectively), which also showed the highest degree of NE lesions. However, the largest variations of diversity and composition of the microbiota were observed in Experiment 2, when birds were raised in floor pens with reused litter, vaccinated against coccidiosis, and challenged with C. perfringens on days 19 to 21.


Assuntos
Enterite/veterinária , Microbioma Gastrointestinal , Necrose/veterinária , Doenças das Aves Domésticas/microbiologia , Criação de Animais Domésticos , Fenômenos Fisiológicos da Nutrição Animal , Animais , Galinhas , Infecções por Clostridium/imunologia , Infecções por Clostridium/prevenção & controle , Infecções por Clostridium/veterinária , Clostridium perfringens/fisiologia , Coccidiose/imunologia , Coccidiose/prevenção & controle , Coccidiose/veterinária , Eimeria/fisiologia , Enterite/microbiologia , Necrose/microbiologia , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/parasitologia , Doenças das Aves Domésticas/prevenção & controle , RNA Ribossômico 16S , Vacinação/veterinária
15.
Vet Parasitol ; 267: 61-68, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30878088

RESUMO

Vaccination has the potential to be the most cost-effective control measure for reducing the economic burden of neosporosis in cattle. In this study, the immune-stimulatory effect of recombinant Neospora caninum dense granule protein 6 (NcGRA6) was confirmed via its triggering of IL-12p40 production in murine macrophages. BALB/c mice were immunized with recombinant NcGRA6 fused with glutathione S-transferase (GST) protein with or without oligomannose-coated-liposomes (OMLs) as the potential adjuvant. Specific IgG1 antibody production was observed from 21 and 35 days after the first immunization in NcGRA6+GST- and NcGRA6+GST-OML-immunized mice, respectively. However, specific IgG2a was detected 1 week after the infection, and IgG2a levels of the NcGRA6+GST- group were higher than those of the NcGRA6+GST-OML-group. Moreover, spleen cell proliferation with concomitant interferon-gamma production was detected in mice immunized with NcGRA6+GST, indicating that a significant cellular immune response was induced. Mouse survival rates against N. caninum challenge infection were 91.7% for NcGRA6+GST and 83.3% for NcGRA6+GST-OML, which were significantly higher than those of control groups (GST-OML: 25%, phosphate-buffered saline: 16.7%). This indicates that naked NcGRA6+GST induced protective immunity. Thus, our findings highlight the immune-stimulating potential of NcGRA6 and the ability to induce protective immunity against N. caninum infection in mice.


Assuntos
Antígenos de Protozoários/imunologia , Coccidiose/prevenção & controle , Neospora/imunologia , Proteínas de Protozoários/imunologia , Adjuvantes Imunológicos/administração & dosagem , Animais , Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/genética , Coccidiose/imunologia , Feminino , Glutationa Transferase/imunologia , Imunoglobulina G/sangue , Interferon gama/imunologia , Subunidade p40 da Interleucina-12/imunologia , Lipossomos/química , Camundongos , Camundongos Endogâmicos BALB C , Proteínas de Protozoários/genética , Proteínas Recombinantes/imunologia , Baço/citologia , Baço/imunologia , Vacinação
16.
Poult Sci ; 98(9): 3471-3480, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-30880340

RESUMO

Coccidiosis is a major gastrointestinal disease caused by several Eimeria species in floor raised chickens. Feeding an antibody to interleukin 10 (aIL-10) ameliorates the negative symptoms of coccidiosis in broilers, i.e., lack of weight gain, decreased feed conversion, and mortality. IL-10 signals by forming a ligand-receptor complex with IL-10 Receptor 1 (IL-10 R1) and IL-10 Receptor 2 (IL-10 R2). In this study, we hypothesize oral antibodies to the IL-10 receptors will neutralize the IL-10 signaling pathway equal to or better than aIL-10 to act as an oral anti-coccidiosis immunotherapy. A total of 5 sequential feed trials, set up as a 4 (diet antibody) × 2 (Eimeria challenge) factorial design, tested oral egg yolk antibodies to a total of 6 IL-10 R1 epitopes and 3 IL-10 R2 epitopes compared to a control antibody diet. A total of 10 pens of 5 chicks/pen/diet antibody/Eimeria challenge were housed for 21 d. On day 3 of age, chicks were either infected or not infected with a 10× dose of an Eimeria vaccine containing Eimeria acervulina, Eimeria tenella, and Eimeria maxima. Pen feed consumption and mean body weights were assessed weekly (d1, d7, d14, and d21); fecal oocyst shedding was assessed on day 10. Data were analyzed using a 2-way ANOVA. No significant interaction on chick weight was observed in chicks fed IL-10 R1 antibodies compared to chicks fed the control antibody was observed. In studies evaluating aIL-10 R2 oral antibodies, infected chicks fed aIL-10 R2: epitope 1 overcame the negative effects of Eimeria infection and had similar 21-d body weight to uninfected chicks (P4 = 0.07). We hypothesized that feeding oral antibodies to the IL-10 receptors would result in equivalent anti-coccidial benefits to aIL-10. However, none of the 6 antibodies to IL-10 R1 epitopes yielded any benefits during Eimeria infection compared to controls. A total of 2 oral antibodies to IL-10 R2 showed promising results equivalent to the aIL-10 immunotherapeutic. Immunofluorescence staining shows that the IL-10R2 significantly increases in abundance in response to Eimeria infection, whereas IL-10R1 does not.


Assuntos
Galinhas , Coccidiose/veterinária , Eimeria/imunologia , Imunoterapia/veterinária , Subunidade beta de Receptor de Interleucina-10/imunologia , Doenças das Aves Domésticas/prevenção & controle , Vacinas Protozoárias/imunologia , Animais , Anticorpos Antiprotozoários/imunologia , Coccidiose/imunologia , Coccidiose/prevenção & controle , Feminino , Subunidade alfa de Receptor de Interleucina-10/genética , Subunidade alfa de Receptor de Interleucina-10/imunologia , Subunidade beta de Receptor de Interleucina-10/genética , Doenças das Aves Domésticas/imunologia
17.
Trop Anim Health Prod ; 51(6): 1375-1381, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30729387

RESUMO

The objective of the present study was to investigate the comparative efficacy of recommended dose of selected anticoccidial drugs Salinomycin and Dinitolmide, while Cocciban at three dose levels on the hematobiochemical, fecal parameters and histopathology of broilers. For this purpose, 420-day-old commercial male broiler chicks were randomly divided into 7 treatment groups with 10 replications of 6 birds each and reared in battery brooders up to 42 days of age. Groups were designated as uninfected unmedicated (T1), infected unmedicated (T2), Cocciban 500 g/ton and infected (T3), Cocciban 750 g/ton and infected (T4), Cocciban 1000 g/ton and infected (T5), Salinomycin 500 g/ton and infected (T6), and Dinitolmide and infected (T7). Groups T2, T3, T4, T5, T6, and T7 were experimentally infected at 21-day-old by 50,000 oocysts of Eimeria species. The mean fecal, lesion scores and oocyst per gram of feces were significantly (p < 0.05) highest in infected unmedicated group, while lowest in the herbal Cocciban 1000 g/ton group than all other infected medicated groups. The hematological studies revealed a reduction in TEC, Hb, and PCV from 0 to 5th day of P.I. in all infected groups except healthy control group. The birds of all the infected groups improved in the values of TEC, Hb, PCV, blood glucose, and total serum protein on 7th day of P.I., but, the improvement was significantly (p < 0.05) better in herbal Cocciban 1000 g/ton treated birds than all other infected groups. Whereas, the TWBC counts were raised from 0 to 7th day of P.I. in all the infected groups compared to healthy control and no significant (p < 0.05) difference was observed in between the infected groups. The histopathological changes consisting of desquamation of epithelial cells, cellular infiltration, hemorrhages, edema, fibrous tissue proliferation, and developing stages of E. tenella at various depths of cecal wall were higher in all the infected groups when compared to Cocciban 1000 g/ton group.


Assuntos
Ceco/efeitos dos fármacos , Galinhas , Coccidiose/veterinária , Coccidiostáticos/farmacologia , Extratos Vegetais/farmacologia , Doenças das Aves Domésticas/tratamento farmacológico , Animais , Ceco/patologia , Coccidiose/prevenção & controle , Dinitolmida/administração & dosagem , Dinitolmida/farmacologia , Eimeria tenella , Fezes , Masculino , Oocistos/efeitos dos fármacos , Piranos/administração & dosagem , Piranos/farmacologia , Distribuição Aleatória
18.
Vet Parasitol ; 266: 18-26, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30736944

RESUMO

In vitro and in vivo studies were performed to assess whether Eimeria tenella (E. tenella) oocysts, exposed to low energy electron irradiation (LEEI), might be considered potential vaccine candidates against cecal coccidiosis. Sporulated oocysts were exposed to LEEI of 0.1 kGy to 10.0 kGy. Reproduction inhibition assays (RIA) were performed in MDBK cells to assess infectivity of sporozoites excysted from irradiated and non-irradiated oocysts. LEEI of 0.1 kGy or 0.5 kGy resulted in 73.2% and 86.5% inhibition of in vitro reproduction (%IRIA), respectively. Groups of 12 one day old (D1) chicken were orally inoculated with Paracox®-8 (G1), 2.0 × 103 non-irradiated oocysts (G2) or 1.0 × 104 irradiated oocysts exposed to LEEI of 0.1 kGy (G3, G4) or 0.5 kGy (G5). Chicken of groups G1, G2, G4 and G5 were challenged 3 weeks later (D21) by a single inoculation of 7.5 × 104 non-attenuated oocysts of the same strain while G3 remained unchallenged. All chickens were subject to necropsy 7 days after challenge (D28) to estimate lesion scores (LS) and oocyst index (OI). A positive control (PC, non-vaccinated, challenged) and a negative control (NC, non-vaccinated, non-challenged) were kept in parallel. Chicken of group G5 had similar weight gain as the Paracox®-8 group (G1) after challenge and higher weight gains as compared to the other vaccinated groups. Feed conversion ratio (FCR) did not differ between chickens inoculated with oocysts irradiated with 0.5 kGy (G5) and negative control (NC) before challenge (1.25-1.52). After challenge FCR was 1.99 (G5) to 2.23 (G4) in the vaccinated chicken compared to 1.76 in group NC. LS and OI were significantly lower in all vaccinated groups as compared to group PC. Progeny oocysts collected from the feces of chickens following vaccination with irradiated oocysts exhibited lower in vitro infectivity/reproduction in MDBK cells with %IRIA of 89.7% and 82.4% for progeny of oocysts irradiated with 0.5 kGy and 0.1 kGy, respectively, suggesting hereditary attenuation by LEEI treatment. Seroconversion was demonstrated by ELISA before challenge (D21) in all vaccinated groups, however, chicken inoculated with irradiated oocysts displayed higher antibody levels than those inoculated with precocious oocysts (G1). In Western blot analysis chicken vaccinated with virulent (G2) or 0.1 kGy-irradiated E. tenella oocysts (G3, G4) showed more protein bands compared to G5 (0.5 kGy). We conclude that LEEI could be a promising technology for production of attenuated oocyst vaccines.


Assuntos
Coccidiose/veterinária , Eimeria tenella/efeitos da radiação , Elétrons , Oocistos/efeitos da radiação , Vacinas Protozoárias/imunologia , Vacinação/veterinária , Animais , Anticorpos Antiprotozoários/sangue , Galinhas/imunologia , Galinhas/parasitologia , Coccidiose/prevenção & controle , Fezes/parasitologia , Doenças das Aves Domésticas/prevenção & controle , Vacinas Protozoárias/administração & dosagem , Soroconversão , Esporozoítos , Vacinas Atenuadas/administração & dosagem , Vacinas Atenuadas/imunologia
19.
Poult Sci ; 98(8): 3240-3245, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-30789214

RESUMO

This study was conducted to evaluate the effect of an encapsulated sodium butyrate (Na-B) with targeted releasing times on growth performance and mitigating the impact of necrotic enteritis in broilers. Two Na-B (30% of Na-B content) products, CMA (2 h releasing time) and CMP (3 to 4 h releasing time), were evaluated in a necrotic enteritis challenge model. The experiment consisted of 4 Na-B treatments (500 and 1,000 ppm of each product) plus 2 control (non-challenged and challenged). A total of 336 Cobb-Cobb male broilers were placed 8 birds per pen into 7 replicate battery cages. On day 14, birds from challenged treatments were orally gavaged with ∼5,000 oocysts of Eimeria maxima. On day 19, 20, and 21, the challenged birds received 1 mL of 108 cfu/mL Clostridium perfringens. Total pen body weight (BW) and feed weight were assessed on day 14, 21, and 28 for BW gain and mortality-adjusted feed conversion ratio (FCR). On day 21, 3 birds were randomly selected per pen and scored for intestinal lesions. The duodenum and jejunum tissue were collected on day 21 and 28 for quantifying intestinal histology. Results revealed that adding CMA at 500 ppm showed significantly higher cumulative BW gain (P < 0.05) compared to the challenged control from day 1 to 21. Adding CMA at 500 ppm also showed the equivalent cumulative FCR that was comparable to the non-challenged control on day 21. The CMA treatments and CMP at 1,000 ppm treatment showed equivalent BW gain compared to the non-challenge control after an additional 7 d post-challenge on day 28. Both products at 500 or 1,000 ppm had the significantly (P < 0.05) lower intestinal lesion scores compared to the challenged control. However, there was no difference in lesion scores among the Na-B treatments. The Na-B product targeted to release in the anterior intestinal tract shows the beneficial effects on BW gain and feed utilization efficiency in current challenge model. Adding encapsulated Na-B product has the potential to mitigate the impact of necrotic enteritis in broilers.


Assuntos
Ácido Butírico/farmacologia , Enterite/prevenção & controle , Necrose/prevenção & controle , Doenças das Aves Domésticas/prevenção & controle , Animais , Peso Corporal/efeitos dos fármacos , Ácido Butírico/administração & dosagem , Galinhas , Infecções por Clostridium/prevenção & controle , Infecções por Clostridium/veterinária , Clostridium perfringens/fisiologia , Coccidiose/prevenção & controle , Coccidiose/veterinária , Preparações de Ação Retardada , Eimeria/fisiologia , Enterite/veterinária , Intestinos/patologia , Masculino , Necrose/veterinária , Doenças das Aves Domésticas/microbiologia , Doenças das Aves Domésticas/parasitologia
20.
Poult Sci ; 98(7): 2919-2926, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30778571

RESUMO

A total of 800 1-day-old Ross 308 male broiler chicks were used in a 5-wk feeding trial to evaluate the effects of commercial feed additive that is composed of blends of essential oil (EO; CRINA Poultry, DSM) and vitamin D3. The birds were randomly assigned to 5 treatments with 10 replicate cages; each stocked with 16 birds and was fed corn-soybean-meal-based basal diet. Dietary treatments included: CON, unvaccinated birds fed basal diet/control; CCO, CON + coccidian oocysts vaccinated birds; EOD1, CCO + Essential oil blends and vitamin D/Prototype 1 (50 µg 25-OH-D3/kg diet, 15 mg CRINA Poultry/kg diet); EOD2, CCO + Prototype 2 (69 µg 25-OH-D3/kg diet, 30 mg CRINA Poultry/kg diet); and EOD3, CCO + Prototype 3 (138 µg 25-OH-D3/kg diet, 50 mg CRINA Poultry/kg diet). On day 7, all birds, except CON, were inoculated with 300 to 500 purified sporulated viable oocysts from Eimeria tenella and Eimeria maxima. As a result of this study, the supplementation of EO blends with vitamin D3 showed trends in improvement (P = 0.075) body weight gain (BWG) compared with CON and CCO during the grower phase (day 7 to 21). An increase (P < 0.05) in BWG and reduction (P < 0.05) in feed conversion ratio (FCR) were observed in birds fed EOD2 diet during day 21 to 35 compared with vaccinated birds without feed additive. The cumulative performance during overall period (day 1 to 35) also showed that BWG was increased and FCR was reduced in EOD2 and EOD3 compared with CON, CCO, and EOD1. Furthermore, the apparent total tract digestibility of dry matter tended (P = 0.06) to increase in EOD2 and EOD3 compared with CON and other treatments. The EOD2 and EOD3 treatments showed increased (P < 0.05) excreta Lactobacillus counts than EOD1. The intestinal lesion score induced by E. tennela in gastro-intestinal tract was lower (P < 0.05) in EOD1, EOD2, and EOD3 treatments compared with CCO. In conclusion, blends of EO and vitamin D3 could be used as anti-coccidial feed additive in broilers with coccidian infection.


Assuntos
Ração Animal/análise , Coccidiose/veterinária , Óleos Voláteis/farmacologia , Doenças das Aves Domésticas/parasitologia , Vitamina D/farmacologia , Animais , Galinhas , Coccidiose/imunologia , Coccidiose/prevenção & controle , Dieta/veterinária , Eimeria/imunologia , Eimeria tenella/imunologia , Masculino , Oocistos , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/prevenção & controle , Vacinação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA