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Anti-PCV2 antibodies in serum, viremia and production parameters (average daily weight gain (ADWG) and mortality) were assessed in piglets immunized with four commercial PCV2 vaccines in the presence of high levels of maternally derived antibodies (MDA). A total of 217 sows were vaccinated (V) at 7 and 4 weeks before farrowing with an inactivated PCV2 vaccine. All piglets derived from these sows (n=2215) were divided into five groups and 3-week-old piglets were injected with one of four different vaccines (A-D): V sows-VA piglets (n=437), V sows-VB piglets (n=424), V sows-VC piglets (n=432) and V sows-VD piglets (n=417). A control group of non-vaccinated piglets (V-NV, n=426) received phosphate-buffered saline (PBS). Sows (n=39) received PBS (non-vaccinated group).
The ADWG of vaccinated piglets (V-VA, V-VB, V-VC and V-VD) ranging from 661 to 669 g/day were significantly higher than the control group (V-NV, 630 g/day), but differences in ADWG between vaccinated groups were not statistically significant. An overall mortality ranging from 7.23% to 9.20% was observed in vaccinated piglets (V-VA, V-VB, V-VC and V-VD) compared with the control group (V-NV, 20.02%). The number of genomic copies of PCV2 in serum for the control group were significantly higher than those of the four vaccinated groups at 10, 15, and 22 weeks of age. Vaccination increased serum antibodies in sows 3- to 4-fold; PCV2-specific antibody titers in sera from piglets were very similar to those of their sows. The antibody titers in vaccinated piglets and V-NV group decreased gradually about 3-fold until the week 10.
In the presence of high MDA levels, piglets immunized with four commercial PCV2 vaccines showed a significantly reduction of PCV2 infected pigs, viral load, number of PCV2-sero positive pigs and mortality rate as well as significantly higher ADWG than those of the V-NV group.
Abel Villa-Mancera, Karina Hernández-Guzmán, Jaime Olivares-Pérez, Pedro Molina-Mendoza. Influence of four commercial porcine circovirus type 2 (PCV2) vaccines on the improvement of production parameters in pigs with maternally derived antibodies. Livestock Science. Volume 190, August 2016, Pages 10–15. http://dx.doi.org/10.1016/j.livsci.2016.05.013