Differences between groups for ADWG, AUC and mortality were compared using an ANOVA test for normally distributed variables and Kruskall-Wallis test for non-normally distributed ones
Differences between groups for ADWG, AUC and mortality were compared using an ANOVA test for normally distributed variables and Kruskall-Wallis test for non-normally distributed ones. Maternally derived antibody effects on ADWG A linear regression MK-8245 Trifluoroacetate was performed to evaluate the strength of association between the PCV-2 antibody titre at the day of vaccination for vaccinated and control piglets and the ADWG during the whole rearing period (from 4 to 25?weeks of age). 198.27??6.14, 0.62??0.01?kg/day and 11% respectively). The overall difference of ADWG between both groups was close to 30?g per day ((SF+ cells) as host. The placebo control consisted of insect cell culture supernatant without PCV-2 capsid protein but made up of carbomer adjuvant. Study design All 4 field trials were performed according to the principles of Good Clinical Practice (GCP) and followed a randomized, negative-controlled, double-blinded, parallel study design. All piglets enrolled into the field studies received a single dose (1?mL) of the PCV-2 vaccine Ingelvac CircoFLEX? (vaccine) or aqueous polymer adjuvant cell culture supernatant (placebo) by intramuscular injection into the neck around weaning (2 to 3 3?weeks of age). Weaning and transfer to the nurseries were performed the day after vaccination (2 to 3 3?weeks of age); pigs were transferred to the fattening models at 9?weeks of age. All animals (vaccinated or not) were kept under conventional housing conditions and were mixed in pens to ensure that all study pigs were housed in comparable conditions, received the same feed and were subjected to the same management practices. At each location change, animals were newly mixed and randomly assigned to the pens according to the usual farm procedure. Sample collection and study parameters Blood samples were collected on the day of inclusion from all piglets, coinciding with the moment of weaning (2 to 3 3?weeks of age), and prior to injection (vaccine or placebo) to determine the presence of PCV-2 antibodies acquired from maternal colostrum (PCV-2 titre). All animals were also individually weighed at inclusion and before slaughter (about 3 and 25?weeks of age). Only data from live/ear-tagged animals at the end of the study were used to carry out further analysis (5563 CD253 animals [91%]; 2835 and 2728 from vaccinated and control groups, respectively). For quantification of PCV-2 viremia, blood samples from 15% of randomly pre-selected study animals, chosen as representative sample animals (total of 956 piglets; 484 from the vaccinated group and 472 from the control group), were collected on weekly or bi-weekly basis throughout the study period. PCV-2 maternally derived antibody (MDA) titre Quantification of the titre of anti-PCV-2 antibodies in porcine serum samples from the first blood sampling was performed at bioScreen GmbH (Mnster, Germany), using an indirect fluorescence antibody titration (IFAT) assay. Briefly, 2C6??104 PCV-2 susceptible cells (VIDO-R1 cells [53, 54]) were seeded onto a 96-well plate at 2C6??104 cells/well, and inoculated with PCV-2 virus (104.5 TCID50/well) for approximately 48?h. After fixation of the cells with ethanol, serial dilutions of porcine serum samples were added to the plates in triplicate and incubated for 1?h at 37?C, allowing antibodies to bind if present in the sera. Plates were washed and stained for 1?h at 37?C with a goat-anti-swine FITC-labelled antibody (Dianova, Germany, #114C095-003), which allowed antigen detection in infected cells using fluorescence microscopy. The plates were read by an independent blinded investigator and individual wells reported as positive or unfavorable. Serum antibody titres were calculated by the method of Reed and Muench using the highest dilution still showing specific IFAT reactivity and MK-8245 Trifluoroacetate the number of positive wells per dilution. The method allowed the detection of antibody titres in a range from 1:5 to 1 1:20480. For the analysis of MDA titres against PCV-2, the data were transformed to base 10 MK-8245 Trifluoroacetate logarithm (log10) [25]. As indicated above a total of 5563 animals were used (2835 and 2728 from vaccinated and control groups, respectively). According to the MDA titre results (those from MK-8245 Trifluoroacetate the first sampling at 2 to 3 3?weeks of age), the animals were classified into two different groups: high (2.5 log10) and low (MK-8245 Trifluoroacetate of two weighing time points divided by.