The present results suggest that the nasal swab results tend to be positive at the beginning of the infection process, then are negative, and finally revert to positive. pigs from the other 2 boars and from the positive controls. SEM studies demonstrated that at 35 d postinoculation a higher proportion of B3 pigs had lower numbers of mycoplasmas attached to the cilia compared with B1 and B2 offspring. No significant differences were observed in temperature and weight gain among groups by ANOVA; however, with use of a 2 2 table, temperature differences were observed Rabbit polyclonal to PNPLA2 between pigs sired by boars B1 and B2 at 4 d postinoculation. No pigs seroconverted, showed gross or microscopic lesions, or had positive ELX-02 disulfate IFAT results. These results provide evidence of differences in patterns of colonization between pigs sired by different boars, suggesting a possible genetic effect. Introduction is a primary agent associated with enzootic pneumonia and the porcine respiratory disease complex, which is considered one of the most important respiratory diseases in modern swine production (1). Both diseases are distributed worldwide and have an important economic impact on the industry. The pathologic, histologic, and ultrastructural changes caused by this microorganism are well described (2,3,4,5); however, little is known of the dynamics in colonization of the upper respiratory tract and the role of host genetics in colonization. colonizes and adheres to the epithelium of the respiratory tract, and this attachment prevents removal by the combined action of the ciliated epithelium and mucus of the respiratory tract (6). Electron microscopic examinations of experimentally infected pigs have demonstrated that attached mycoplasmas are located predominantly between cilia and microvilli of the tracheal and bronchial epithelial cells. This attachment causes epithelial cell alterations, seen as progressive cellular damage at different postinoculation times (6). There ELX-02 disulfate are no published reports suggesting ELX-02 disulfate that susceptibility to colonization is influenced by a pig’s genetic makeup. A better understanding of the process of colonization would be a first step leading to alternative tools for prevention and treatment of mycoplasmosis. The purpose of this study was to create a model to study respiratory colonization and to determine if there are differences in the colonization of pigs sired by different boars of the same genetic line following experimental inoculation with was used, and the pigs were studied over a 35-day period. Materials and methods Animals Three boars of the same genetic line (B1, B2, and B3) were each mated to 3 different sows. Forty-two pigs produced by these matings (14 from each boar) were selected for this study from a farm clinically and serologically negative for and porcine reproductive and respiratory syndrome virus (PRRSV). The pigs were weaned at 2 wk of age and transported to the University of Minnesota isolation facility, where they were randomly allocated to 2 experimental groups. The Institutional Animal Care and Use Committee approved the protocol. Experimental design The experiment was performed as a double-blind design, so that the boar of origin for each individual pig was unknown, samples being identified by a random number. The experimental groups were distributed as follows: group 1 (treatment) included 36 pigs, 12 from each boar; group 2 (negative controls) included 6 pigs, 2 from each boar; and group 3 (positive controls) included 4 specific pathogen-free (SPF) pigs of a different genetic origin. This last group was included because we had previously successfully colonized pigs of this origin. Half of the pigs were necropsied at 11 d postinoculation and the other half at 35 d postinoculation. Differences in colonization were contrasted between the boars. After arrival at the isolation units, the pigs were settled for 1 wk, during which the animals were not treated. To confirm their status, the pigs were bled and the serum was separated from each sample and tested by enzyme-linked immunosorbent assay (ELISA) for antibodies. ELX-02 disulfate In addition, nose swabs were obtained to be evaluated having a nested polymerase chain reaction (N-PCR) test. At 3 wk of age the pigs were challenged with ELX-02 disulfate 1 mL of a culture comprising 1 106 color.