Topic: Using serum antibody levels of piglets after vaccination to evaluate maternal antibody interference and vaccine immunity effects
Introduction:
Understanding the level of maternal antibody (MDA) in pigs is crucial to determine the appropriate vaccination timing, mainly to understand when maternal antibody is low enough to interfere with the vaccine immunity effect.
The purpose of this study was to evaluate the serological response after two 1ml injections of porcine cyclovirus type 2 (PCV2) and Mycoplasma swine pneumoniae (Mhp) double vaccine at 3 and 6 weeks of age (WOA). In addition, this study also analyzed whether maternal antibody (MDA) levels during the first vaccination would interfere with the vaccine immunity effect. The overall goal is to determine whether serological results will be useful if both vaccinations are administered simultaneously.
Material Method:
Comparison of maternal antibodies from eight sow farms. Four of the sows were vaccinated (PBV) before breeding, and the other four were vaccinated (N-PBV) before breeding. 30 sows were selected from the PBV group and the N-PBV group, and they were divided into 3 groups according to the parity (P): P1, P2-3 and P4+.
blood sample collection and vaccine immunization were completed the day before weaning. The largest piglet was selected in each litter for blood sampling and labeling, and then the whole litter was injected with 1 mL of the vaccine.
After 3 weeks of feeding (at 6 weeks of age), the whole nest of piglets was injected with 1ml of vaccine for the second time. Piglet blood samples were collected for analysis 3 weeks after the second immunization (9 weeks of age).
Results and discussion:
Research results shown in Table 1, porcine cyclovirus type 2 (PCV2) antibody positive: titer ≥1280; Mycoplasma septic pneumoniae (Mhp) antibody positive: S/P>0.400. After the first immunization of
, serum test was performed on 3-week-old piglets:
pig cyclovirus type 2 (PCV2) antibody results: The positive rate of the N-PBV group was 3/30, and the positive rate of the PBV group was 28/30.
Mycoplasma swine pneumoniae (Mhp) antibody results: The positive rate of the N-PBV group was 13/30 (the average positive rate was 0.428), and the positive rate of the PBV group was 24/30 (the average positive rate was 0.918).
After the second immunization, serum tests were performed on 9-week-old piglets:
Pig Circovirus Type 2 (PCV2) antibody results: The positive rate of the N-PBV group was 19/21; the positive rate of the N-PBV group was 7/30. The results of the antibody test of
on Mycoplasma sypneumoniae (Mhp): The positive rate of the N-PBV group was 18/21, and the positive rate of the PBV group was 25/30.
The above research results show that maternal antibodies (MDA) can interfere with the immune response of porcine cyclovirus type 2 (PCV2) and Mycoplasma swine pneumoniae (Mhp), which is of great significance to the timing of immunization of porcine cyclovirus type 2 (PCV2) and Mycoplasma swine pneumoniae (Mhp) vaccines.
In addition, post-immune monitoring can be better performed by measuring the levels of Mycoplasma swine pneumoniae (Mhp) antibodies, because pigs are more likely to be immune to the circovirus type 2 (PCV2) parent antibody (MDA) is higher when immunized, making it difficult to monitor post-immune antibodies.
Table 1: Test results before and after immunization of PCV2 and Mhp vaccines
Source of this article: Online editing, if reprinted, please indicate the source: http://news.xinmunet.com/2021/14514.html
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