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Mazutti K.,Pontifical Catholic University of Parana | Costa L.B.,Programa de Pos Graduacao em Ciencia Animal | Nascimento L.V.,Programa de Pos Graduacao em Ciencia Animal | Filho T.F.,Imunova Analises Biologicas Ltda | And 3 more authors.
Semina:Ciencias Agrarias | Year: 2016

For the last several decades, antimicrobial compounds have been used as feed additives to promote piglet growth at weaning, through the prevention of subclinical and clinical disease. However, few studies have assessed the influence of these antibiotics on the immune response of nursery pigs, as well as the relation between performance, health, and immunity of animals that receive feed additives. Therefore, the present study aimed to evaluate the effects of colistin and tylosin when used as feed additives on the performance, incidence of diarrhea, and immune response of nursery pigs. In this study, 72 weaned pigs (average age, 28 days) were allotted into one of three treatment groups: A control group (feed with no antibiotics), tylosin group (feed containing 22 ppm tylosin), and colistin group (feed containing 20 ppm colistin). Weekly, during a five week period, the average daily feed intake, average daily gain, and feed conversion ratio of the pigs were evaluated. Stools were scored daily, in accordance with a fecal texture scale. Blood samples were collected on the day of housing (d0) and on d7, d21, d28, and d35 for immune cell phenotyping. The results of this study showed that piglets in both the colistin and tylosin groups exhibited a significantly higher average daily feed intake, resulting in a higher body weight at the end of the experimental period (d35) when compared with piglets from the control group. Colistin and tylosin also significantly reduced the incidence of diarrhea. Colistin and tylosin modulated the piglets' immune responses, particularly on d28, by changing the percentage of circulating B lymphocytes, CD4+CD8+ T cells, and the CD4:CD8 ratio.


Filho T.F.,Imunova Analises Biologicas LTDA | Filho T.F.,Federal University of Paraná | Favaro Jr. C.,Imunova Analises Biologicas LTDA | Favaro Jr. C.,Federal University of Paraná | And 7 more authors.
Avian Diseases | Year: 2013

Avian pathogenic Escherichia coli is a current problem in the poultry industry, causing mortality and economic losses. This paper evaluates the dynamics in immune response after the use of spray vaccination against E. coli and, thereby, seeks to understand how the vaccine can provide protection. During the early stages of response to vaccination the presence of antigen-presenting cells is predominant, but these diminish within the first 7 days after vaccination. The immune correlate of protection of vaccination using the E. coli vaccine Poulvac E. coli (aroA-deficient mutant strain) probably does not depend on the production of circulating antibodies (as assessed through the presence of B lymphocytes) and is linked to the presence of CD4+TCRVβ 1+. These cells act on mucosa tissue stimulating the production of immunoglobulin A. Vaccination stimulated a high state of immunocompetence, as assessed by measurement of several cellular subsets. This state of "immune alertness," however, may be associated with reduced weight gain. The high presence of naive and memory CD8 cells in the vaccinated group at 14 and 21 days postvaccination may indicate greater ability in the future to prevent tissue invasion by E. coli, based on the possibility that these cells will proliferate rapidly to a new stimulus. The simultaneous use of vaccine with the antibiotic ceftiofur sodium interferes with the immune response obtained through vaccination. In combination, the data obtained in this study indicate that the immune response produced by a spray vaccine against E. coli is mainly a cellular response, especially relevant to the sites in contact with the pathogen. It is suggested that there is a strong cell migration to the mucous membranes, where macrophages act first and then lymphocytes take part to protect the host. It is believed that recruited lymphocytes will act in the production of secreted IgA, which probably plays a greater role in the defense when compared with circulating immunoglobulins. The assessment of cellular dynamics by flow cytometry made it possible to elucidate the operation mechanism of the live E. coli vaccine. © American Association of Avian Pathologists.


PubMed | Imunova Analises Biologicas LTDA
Type: Journal Article | Journal: Avian diseases | Year: 2013

Avian pathogenic Escherichia coli is a current problem in the poultry industry, causing mortality and economic losses. This paper evaluates the dynamics in immune response after the use of spray vaccination against E. coli and, thereby, seeks to understand how the vaccine can provide protection. During the early stages of response to vaccination the presence of antigen-presenting cells is predominant, but these diminish within the first 7 days after vaccination. The immune correlate of protection of vaccination using the E. coli vaccine Poulvac E. coli (aroA-deficient mutant strain) probably does not depend on the production of circulating antibodies (as assessed through the presence of B lymphocytes) and is linked to the presence of CD4+TCRVbeta1+. These cells act on mucosa tissue stimulating the production of immunoglobulin A. Vaccination stimulated a high state of immunocompetence, as assessed by measurement of several cellular subsets. This state of immune alertness, however, may be associated with reduced weight gain. The high presence of naive and memory CD8 cells in the vaccinated group at 14 and 21 days postvaccination may indicate greater ability in the future to prevent tissue invasion by E. coli, based on the possibility that these cells will proliferate rapidly to a new stimulus. The simultaneous use of vaccine with the antibiotic ceftiofur sodium interferes with the immune response obtained through vaccination. In combination, the data obtained in this study indicate that the immune response produced by a spray vaccine against E. coli is mainly a cellular response, especially relevant to the sites in contact with the pathogen. It is suggested that there is a strong cell migration to the mucous membranes, where macrophages act first and then lymphocytes take part to protect the host. It is believed that recruited lymphocytes will act in the production of secreted IgA, which probably plays a greater role in the defense when compared with circulating immunoglobulins. The assessment of cellular dynamics by flow cytometry made it possible to elucidate the operation mechanism of the live E. coli vaccine.

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