| In this study, piglets were administered Mycoplasma hyopneumoniae domestic and imported bacterin, respectively. Then, to assess their efficacy, the specific serum antibody titers, positive ratio for Mycoplasma hyopneumoniae of PCR detection, EP compatitble lung lesion and average daily weight gain of piglets were compared.A total thirty-six 21-day-old piglets were allocated to three average groups randomly, named group A, group B and group C, respectively. Group A was domestic bacterin group, group B was imported bacterin group, Group C was control. At 21-day and 35-day of age, piglets in group A were administered domestic bacterin,2ml per pig. Piglets in Group B were administered imported bacterin at 21-day of age,1ml per pig. The control piglets were not vaccinated. At 49-day of age, all piglets were challenged intratracheally with Mycoplasma hyopneumoniae with high virulence named MY-99. At 69-day of age, a necropsy was performed.Blood samples were collected at 21,35,49 and 69-day of age, the titer of specific antibody was detected by ELISA and the S/P ratio was used to express titers. At 21-day of age, the average S/P ratio for group A, B and C was all less than 0.3, were 0.224,0.202 and 0.199, respectively.And all piglets were negative. At 35-day of age, the S/P ratio of group A, B and C were 0.526,0.558 and 0.174, respectively. Difference among group A and group B was not significant (P>0.05), they are significantly different from group C (P< 0.01). The percents for positive pigs of group A, B and C were 75.0%,83.3% and 0%, respectively. At 49-day of age, the S/P ratio of group A, B and C were 0.702,0.678 and 0.161, respectively. Difference between group A and group B was not significant (P>0.05), they are significantly different from group C (P<0.01). The percents for positive pigs of both group A and B were 100%, and for group C was 0%. At 69-day of age, the S/P ratio of group A, B and C were 0.819,0.853 and 0.414, respectively. Difference between group A and group B was not significant (P>0.05), they are significantly different from group C (P <0.01). The percent for positive pigs of both group A, and B were still 100%, and for group C was 58.3%.Nasal swabs were collected at 21,35 and 49-day of age, Bronchoalveolar Lavage Fluid was collected at 69-day of age, Mycoplasma hyopneumoniae was detected with PCR. All of the nasal swabs were negative. For Bronchoalveolar Lavage Fluid, the percents for positive pigs of group A, B and C were 75%,66.7% and 100%, respectively.After necropsy, the Mycoplasma pneumoniae-like lung lesion was assessed. According to the lung lesion score, reduction ratio of lung lesion was calculated. Samples of lung were collected to examine the histopathological changes. About the lung lesion score, difference between group A and B was not significant (P>0.05), they are significantly different from group C (P<0.01). The lung lesion reduction ratio of group A and B were 78.44% and 81.48%, respectively. Lung sections were examined, and the main histopathological finding was interstitial pneumoniae.The body weight of pigs at 21-day and 65-day of age was weighted, and the average daily weight gain was calculated. For group A, B and C, the average daily weight gain were 398.52 g/pig/d,410.95 g/pig/d and 364.47 g/pig/d, respectively. The diffierence between group A and B was not significant (P >0.05), they are significantly different from group C (P<0.01).The results described above indicate that the Mycoplasma hyopneumoniae domestic bacterin could stimulate piglets to produce specific antibody with high titer, reduce the positive ratio for Mycoplasma hyopneumoniae of PCR detection and lung lesion after challenging, and improve the average daily weight gain of piglets.It's efficacy was similar with the imported bacterin. |
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