The Effects of Oral Antibiotic Therapy on Productivity and Immune Function Following Challenge with E. coli and Rotavirus

Early weaning programs have been aimed at the control and elimination of respiratory infections in the young pig. Segregation from their dams at less than 21 days, batch rearing with all-in and all-out by room, building, or site, and proper biosecurity (cleaning, disinfecting, and quarantine) are mandatory to implement early weaning programs1. Early weaning with all its components gives a tremendous economic advantage to those who use this technology. This technology however does not come without a cost. This requires necessary building sites, scheduling and a high level of management. Enteric infections such as neonatal coccidiosis and post weaning diarrhea problems have not been prevented by early wean programs. Although the Pork Quality Assurance Program has been developed to achieve the highly desirable goal of reduced antibiotic use, there are feed and water medication is needed for prevention and control of enteric infections. We are interested in the effects of low levels of conventional water and feed grade antibiotic treatments on performance and immunological parameters of the young pig infected with the common enteric pathogens, E. coli and rotavirus. Previously, we had tested this treatment at both a research facility and a commercial operation and had shown increased production and decreased immunological response in the treated animals23. We have established that the use of such a program would be a benefit to those producers who do not have the production facilities that would allow early weaning (7-10 days) and/or multi-site production. However the effect of these oral treatments on minimizing production losses and activation of the immune system following infection with enteric infections has not been established. The purpose of this study was to measure production and immunological parameters in orally medicated and control animals following a post weaning E. coli and rotavirus challenge

The Effect of Diet and Oral Antibiotic Therapy on Immune Function and Productivity in Young Pigs

Medicated early weaning programs have been shown to be an excellent method to control disease incidence in the young pig. Additional research by Dritz, et al1, showed that early weaning at 7-10 days without medication resulted in significant weight gains over conventional weaning at 14-17 days. We were interested in the effects of low levels of conventional water and feed grade antibiotic tratments on performance and immunological parameters of the young pig in a commercial operation. Previously, we had tested this treatment at a research facility and had shown increased production and a decreased polyclonal immunological response in the reated animals23. The use of such a program would be a benefit to producers who do not have the production facilities that allowing for early weaning (7-10 days) and/or multisite production. A study was conducted to determine the effect of AureomycinTM and Aureo-SulmetTM on production. The study was a 2X2 factorial experiment to determine the effect of weaning treatment and nutrition level on immune response

Serologic Response of Gnotobiotic Pigs Challenged with Actinobacillus Pleuropneumoniae Serotype 5 or Actinobacillus Suis Field Isolates

Three studies, a pilot study with conventional early-weaned pigs and two studies with gnotobiotic pigs were completed. The piolot study indicated that conventional pigs could be challeneged with at least 107 colony forming units (cfu) or Actinobacillus pleuropneumonia (APP) or Actinobacillus suis (A suis) without developing clinical signs. No serological response was detected in these pigs. In the first gnotobiotic study, nine pigs were used: 3 control, 3 APP or 3 A. suis. The two groups of challened pigs failed to respond clinically or serologically to the intial callenege of 106 cfu or either APP or A. suis but the APP pigs did respond clinically and serologically to a second challenge of 107 cfu. A second study with twenty gnotobiotic pigs was completed. Eight pigs were assigned to the Actinobacillus pleuropneumoniae (APP) serotype 5 group; eight pigs were assigned to the Actinobacillus suis (A. suis) group and 4 pigs were assigned to the control group. Each group of gnotobiotic pigs were challenged with 107 colony forming units (cfu) of either APP or A. suis. In both gnotobiotic studies, serological tests indicated that the hemolysin neutralization test (HNT) specificity was poor as it was unable to discriminate between APP or A. suis infections. The HNT test detected more APP positive animals than any other test and detected APP infected animals one-month post challenge. In the first gnotobiotic study, APP infected pigs were detected at one-two weeks post challenge with the APP5 ELISA developed by the University of Montreal (ELISA-M). ELISA-M was a more sensitive test than the APP5 ELISA developed by Oxford Laboratories (ELISA-O). In the second gnotobiotic study, the ELISA-M and ELISA-O failed to detect any APP 5 infected animals. In both gnotobiotic studies, the complement fixation test failed to detect any animals and was insensitive to APP infections

Comparação dos testes de virusneutralização contra os genótipos 1 e 2 do vírus da diarreia viral bovina (BVDV-1 e BVDV-2) em bovinos de rebanhos naturalmente infectados

Os resultados dos testes de virusneutralização (VN) contra os genótipos do vírus da diarreia viral bovina (BVDV-1 e BVDV-2), bem como os respectivos títulos de anticorpos, foram comparados em 1.925 amostras de soro sanguíneo obtidas de rebanhos bovinos naturalmente infectados e não vacinados contra o BVDV, provenientes dos Estados de São Paulo e Minas Gerais. A proporção de amostras reagentes entre os genótipos foi analisada pelo Teste de McNemar, e os títulos de anticorpos das amostras reagentes ao BVDV-1 e ao BVDV-2 foram comparados pelo Teste de Wilcoxon. Não foi verificada discordância na proporção de bovinos reagentes ao BVDV-1 e ao BVDV-2 (P>0,05). No entanto, houve discordância entre os títulos de anticorpos detectados nos testes de VN contra os genótipos 1 e 2 do BVDV (P0.05). However, there was a disagreement among titers of antibodies detected in the VN tests against BVDV genotypes (P<0.0001). Although the proportion of reagent animals to BVDV genotypes was similar, false negative results would be obtained if 67 samples (3.5%) had been submitted only to VN test against BVDV-1, and 51 samples (2.65%) only against BVDV-2. Some herds had higher titers of antibodies for BVDV-1, while others for BVDV-2, thus demonstrating the occurrence of infection by different virus genotypes among the analyzed herds. Therefore, these results demonstrated the need for inclusion of both BVDV genotypes in VN tests.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Estadual Paulista Faculdade de Ciências Agrárias e Veterinárias Departamento de Medicina Veterinária Preventiva e Reprodução AnimalUniversidade Estadual Paulista Faculdade de Ciências Agrárias e Veterinárias Departamento de Ciências ExatasUniversidade Estadual Paulista Faculdade de Ciências Agrárias e Veterinárias Departamento de Medicina Veterinária Preventiva e Reprodução AnimalUniversidade Estadual Paulista Faculdade de Ciências Agrárias e Veterinárias Departamento de Ciências Exata

Avaliação da transferência de citocinas para bezerros neonatos via ingestão de colostro de fêmeas bovinas Holandesas

Para a avaliação da transferência de citocinas para o sangue de bezerros neonatos via ingestão de colostro de fêmeas bovinas holandesas, foram utilizados 15 bezerros nascidos de parto eutócico, distribuídos igualmente por três grupos experimentais (n=5): G1- receberam dois litros de colostro fresco provenientes de suas próprias mães; G2- receberam dois litros de colostro provenientes de "pool" de colostro congelado e o G3- foram alimentados apenas com leite. Nestes grupos foram coletadas amostras de sangue em cinco tempos durante os primeiros quinze dias de vida e mensuradas as concentrações das citocinas Interleucina-1 β (IL-1b), Interleucina-6 (IL-6), Fator de necrose tumoral- α (TNF-a) e Interferon-γ (IFN-γ). Também se mensurou tais citocinas (IL-1 β, IL-6 e TNF-α) nos sobrenadantes do colostro de do "pool" de colostro fornecidos aos bezerros dos grupos G1 e G2 respectivamente. Verificou-se a transferência das citocinas IL-1b, IL-6, TNF-a e IFN-γ pela presença no soro dos bezerros do grupo G1, enquanto que nos demais grupos (G2 e G3) não foram detectadas

A Role for Bovine Herpesvirus 1 (BHV-1) Glycoprotein E (gE) Tyrosine Phosphorylation in Replication of BHV-1 Wild-Type Virus but Not BHV-1 gE Deletion Mutant Virus

AbstractBovine herpesvirus 1 (BHV-1), an alphaherpesvirus, is a major pathogen that causes respiratory and reproductive infections. We observed tyrosine phosphorylation of a 95-kDa viral protein and dephosphorylation of 55- and 103-kDa cellular proteins during the course of BHV-1 infection. We demonstrated BHV-1 glycoprotein E (gE) to be the tyrosine phosphorylated viral protein by immunoprecipitation. Inhibition of phosphorylation of BHV-1 gE by tyrosine kinase inhibitors genistein and tyrphostin AG1478 substantially lowered the viral titer in Madin-Darby bovine kidney cells. The decrease in viral titer was directly proportional to the decrease in phosphorylation of the BHV-1 gE. Interestingly, these kinase inhibitors did not inhibit the replication of the BHV-1 gE deletion mutant virion (BHV-1gEΔ3.1). Our findings suggest that the wild-type BHV-1, with a functional gE protein, uses a different pathway of signaling events than the BHV-1 gE deletion mutant in replication. Our results indicate that the tyrosine phosphorylation of the cytoplasmic tail of BHV-1 gE is an important post-translational modification of the functional protein. An application of this study may be the use of tyrosine kinase inhibitors in controlling the BHV-1 infection

Comparison of the breadth and complexity of bovine viral diarrhea (BVDV) populations circulating in 34 persistently infected cattle generated in one outbreak

AbstractExposure to bovine viral diarrhea viruses (BVDV) results in acute and persistent infections. Persistent infections result from in utero exposure during the first trimester of gestation. Clinical presentation, in persistently infected cattle (PI), is highly variable. The reasons for this variation is largely unknown. The BVDV circulating in PI exist as quasispecies (swarms of individual viruses). An outbreak resulting in 34 PI cattle presented an opportunity to compare a large number of PI׳s. Methods were developed to compare the circulating viral populations within PI animals. It was found that PI animals generated in the same outbreak carry circulating viral populations that differ widely in size and diversity. Further, it was demonstrated that variation in PI viral populations could be used as a quantifiable phenotype. This observation makes it possible to test the correlation of this phenotype to other phenotypes such as growth rate, congenital defects, viral shed and cytokine expression