RESUMO

The bovine tick Rhipicephalus (Boophilus) microplus is found in several tropical and subtropical regions of the world. This parasite transmits pathogens that cause disease, such as babesiosis (Babesia bovis and B. bigemina) and anaplasmosis (Anaplasma marginale). Tick infestations cause enormous livestock losses, and controlling tick infestations and the transmission of tick-borne diseases remains a challenge for the livestock industry. Because the currently available commercial vaccines offer only partial protection against R. (B.) microplus, there is a need for more efficient vaccines. Several recombinant antigens have been evaluated using different immunization strategies, and they show great promise. This work describes the construction and immunological characterization of a multi-antigen chimera composed of two R. (B.) microplus antigens (RmLTI and BmCG) and one Escherichia coli antigen (B subunit, LTB). The immunogenic regions of each antigen were selected and combined to encode a single polypeptide. The gene was cloned and expressed in E. coli. For all of the experiments, two groups (treated and control) of four Angus heifers (3-6 months old) were used. The inoculation was performed via intramuscular injection with 200 µg of purified recombinant chimeric protein and adjuvated. The chimeric protein was recognized by specific antibodies against each subunit and by sera from cattle inoculated with the chimera. Immunization of RmLTI-BmCG-LTB cattle reduced the number of adult female ticks by 6.29% and vaccination of cattle with the chimeric antigen provided 55.6% efficacy against R. (B.) microplus infestation. The results of this study indicate that the novel chimeric protein is a potential candidate for the future development of a more effective vaccine against R. (B.) microplus.

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RESUMO

Neospora caninum, an Apicomplexan parasite that can causes abortion, is responsible for considerable economic and reproductive losses in livestock. The purpose of the present study was to determine whether recombinant NcSRS2 is a suitable indirect ELISA antigen for determining specific immune response to N. caninum in sheep. A total of 441 serum samples were subjected to IFAT and rNcSRS2 based-ELISA, with both tests performing similarly. The sensitivity and specificity of indirect ELISA were 98.6 and 98.3%, respectively. The kappa index shows 0.98 concordance between the two tests, which is considered excellent. Seroprevalences of 30.8 and 32.0% were detected by IFAT and indirect ELISA, respectively, showing these tests did not differ significantly on this measure (p > 0.05). Serological analysis showed that HisG tag was detected by Western Blotting recognizing rNcSRS2 protein. The potential value of rNcSRS2-based ELISA as a highly specific and sensitive tool for serological diagnosis is also supported by the strong agreement found between IFAT and ELISA. The results support the potential use of recombinant protein NcSRS2 as an antigen in indirect ELISA in sheep.

Assuntos

RESUMO

Neospora caninum, an Apicomplexan parasite that can causes abortion, is responsible for considerable economic and reproductive losses in livestock. The purpose of the present study was to determine whether recombinant NcSRS2 is a suitable indirect ELISA antigen for determining specific immune response to N. caninum in sheep. A total of 441 serum samples were subjected to IFAT and rNcSRS2 based-ELISA, with both tests performing similarly. The sensitivity and specificity of indirect ELISA were 98.6 and 98.3 percent, respectively. The kappa index shows 0.98 concordance between the two tests, which is considered excellent. Seroprevalences of 30.8 and 32.0 percent were detected by IFAT and indirect ELISA, respectively, showing these tests did not differ significantly on this measure (p > 0.05). Serological analysis showed that HisG tag was detected by Western Blotting recognizing rNcSRS2 protein. The potential value of rNcSRS2-based ELISA as a highly specific and sensitive tool for serological diagnosis is also supported by the strong agreement found between IFAT and ELISA. The results support the potential use of recombinant protein NcSRS2 as an antigen in indirect ELISA in sheep.

Neospora caninum é um parasito Apicomplexa que pode causar abortos e é reconhecido como agente importante responsável por perdas econômicas e reprodutivas. Este estudo avaliou a proteína recombinante NcSRS2 como antígeno para ELISA indireto na determinação de resposta imune para N. caninum em ovinos. 441 amostras de soro foram analisadas por IFAT e ELISA indireto com rNcSRS2 e ambos os testes revelaram comportamento similar. A sensibilidade e especificidade de ELISA indireto foram 98,6 e 98,3 por cento, respectivamente. O índice kappa mostrou uma concordância entre os dois testes com valor de 0,98, que é considerado excelente. Prevalências de 30,8 e 32,0 por cento detectadas por IFAT e ELISA indireto, respectivamente, mostraram que os testes não diferiram significativamente nesse aspecto (P > 0.05). A análise sorológica revelou que os anticorpos específicos da cauda de histidina reconheceu por Western Blotting a proteína recombinante NcSRS2. O valor potencial do ELISA indireto baseado no antígeno rNcSRS2 como ferramenta altamente específica e sensível para diagnóstico sorológico é também reforçado pela alta concordância dos valores obtidos com IFAT e com ELISA indireto. Esses resultados respaldam o uso potencial da proteína rNcSRS2 como antígeno em ELISA indireto em ovinos.

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Foram avaliados os efeitos da aplicação de Impact P® sobre a cama de aviário de matrizes de corte mediante o monitoramento de parâmetros microbiológicos. O Impact P® é um produto formulado através de Bacillus subtillis e suas enzimas que atuam sobre os dejetos animais e matéria orgânica, utilizando-os como fonte alimentar, visando melhorar as condições da cama dentro de aviários. Na 58ª semana de idade das matrizes foi trocado todo material de cama e então aplicados os seguintes tratamentos: T1- controle; T2 - Impact P® na dosagem de 2,5gm-2 de cama; T3 - Impact P® na dosagem de 5,0g m-2 de cama. Foram realizadas contagens de enterobactérias totais em agar McConkey em amostra de cama nova e após 3, 10, 17, 24 e 31 dias de uso da cama pelas aves e tratamentos com Impact P®. A análise estatística foi realizada no procedimento General Linear Models - GLM que utiliza o método dos quadrados mínimos, em um esquema fatorial 3x4 (tratamento x tempo de uso da cama) em delineamento completamente casualizado, com quatro repetições por tratamento, sendo as médias comparadas pelo teste de Tukey. A dosagem de 5,0g de Impact P® por m² de cama foi eficiente para reduzir em aproximadamente 13% a contagem logarítmica total de enterobactérias em comparação com o grupo não tratado (2,89 versus 3,31log10 (UFC), respectivamente, P<0,05).

This study aimed to evaluate the utilization of Impact P® in used litter from floor pens of broiler breeders through the monitoring of microbiological parameters. Impact P® is a commercial product obtained from Bacillus subtillis and it enzymes. Using animal litter and organic matter as a feed source, the product was designed to improve the quality of floor pens of broiler breeders. When hens aged 58 weeks, all used floor pens material was replaced with a new one and the following treatments were tested: T1 - control; T2 - 2.5g Impact P® m-2 litter; T3- 5.0g Impact P® m-2 litter. Counting of number of enterobacterium colonies in agar Mac-ConcKey was performed in a sample of new floor pens material and after 3, 10, 17, 24 and 31 days of litter treatment with Impact P®. The statistical analysis was accomplished with the General Linear Models - GLM procedure, using the minimum square method in a 3x4 factorial (treatment vs. time of floor pens utilization), in a completely randomized design with four replications. The averages were compared by Tukey test. The utilization of 5.0g Impact P® m-2 litter was efficient to reducing approximately 13% logarithmic total counting of the enterobacterium in comparison to the untreated group (2.89 versus 3.31log10 (CFU), respectively, P<0.05).