Antibody responses to porcine reproductive and respiratory syndrome virus, influenza A virus, and Mycoplasma hyopneumoniae from weaning to the end of the finisher stage in fourteen groups of pigs in Ontario, Canada

Abstract

Background: Respiratory diseases are among the most important factors affecting swine farm productivity in Canada. The objectives of this study were to investigate antibody responses to porcine reproductive and respiratory syndrome virus (PRRSV), influenza A virus (IAV), and Mycoplasma hyopneumoniae (M. hyopneumoniae) from weaning to the end of the finisher stage on a subset of commercial swine farms in Ontario, Canada, and to examine the association between nursery diet and antibody responses.

Results: Overall, older pigs were more likely to test seropositive for PRRSV and less likely to test seropositive for M. hyopneumoniae (p < 0.001). Pigs were more likely to test seropositive for IAV at weaning and the end of the grower and finisher stages compared to the end of nursery (p < 0.001). Pigs that were seropositive for IAV were more likely to test seropositive for both PRRSV and M. hyopneumoniae (p < 0.001). Two, 9, and 4 groups that had more than 20% of pigs seropositive to PRRSV, IAV, and M. hyopneumoniae, respectively, from the end of nursery to the end of finisher were classified as seropositive. Pigs fed a plant-based (low complexity) diet during nursery were more likely to be seropositive for PRRSV (p < 0.001) but there were no significant differences in seropositivity to IAV or M. hyopneumoniae due to nursery diet complexity.

Conclusions: This study provides information regarding changes in serum antibody in pigs across different stages of production and highlights periods of vulnerability. Additionally, these findings may encourage further research into the effects of nursery diet complexity on disease susceptibility and immune response.

Keywords: Antibody response; ELISA; Influenza A virus; Mycoplasma hyopneumoniae; Nursery diet; Porcine reproductive and respiratory syndrome; swine.

Fig. 1

Percentage of pigs seropositive for PRRSV, IAV, and M. hyopneumoniae from the end of nursery to the end of finisher. This figure depicts the percentage of pigs that were seropositive for porcine reproductive and respiratory syndrome virus (PRRSV), influenza A virus (IAV), and Mycoplasma hyopneumoniae in seropositive groups at each stage of production from the end of nursery to the end of the finisher stage. Note: Two, 9 and 4 groups were classified as seropositive for PRRSV, IAV, and M. hyopneumoniae, respectively. *Significantly different from end of nursery (p <  0.05)

Fig. 2

Combination frequency of pigs that were seropositive for PRRSV at different stages of production. This figure displays pigs that were tested at 4 visits and were seropositive for porcine reproductive and respiratory syndrome virus (PRRSV) at least once throughout production. The data are presented as intersections for each combination of production stages in which pigs were seropositive, with seropositivity represented by dots in the horizontal axis. The number of seropositive pigs per intersection are displayed above the corresponding bar and arranged from the largest intersection to the smallest. Dots are connected by a line if pigs were seropositive at more than 1 production stage. For example, the largest number of pigs were seropositive for PRRSV only at weaning, followed by pigs that were only seropositive at the end of the finisher stage, etc.

Fig. 3

Combination frequency of pigs that were seropositive for IAV at different stages of production. This figure displays pigs that were tested at 4 visits and were seropositive for influenza A virus (IAV) at least once throughout production. The data are presented as intersections for each combination of production stages in which pigs were seropositive, with seropositivity represented by dots in the horizontal axis. The number of seropositive pigs per intersection are displayed above the corresponding bar and arranged from the largest intersection to the smallest. Dots are connected by a line if pigs were seropositive at more than 1 production stage. For example, the largest number of pigs were seropositive for IAV only at weaning, followed by pigs that were seropositive at all four production stages, etc.

Fig. 4

Combination frequency of pigs that were seropositive for M. hyopneumoniae at different stages of production. This figure displays pigs that were tested at 4 visits and were seropositive for Mycoplasma hyopneumoniae (M. hyopneumoniae) at least once throughout production. The data are presented as intersections for each combination of production stages in which pigs were seropositive, with seropositivity represented by dots in the horizontal axis. The number of seropositive pigs per intersection are displayed above the corresponding bar and arranged from the largest intersection to the smallest. Dots are connected by a line if pigs were seropositive at more than 1 production stage. For example, the largest number of pigs were seropositive for M. hyopneumoniae only at weaning, followed by pigs that were only seropositive at the end of the finisher stage, etc.

Fig. 5

PRRSV, IAV, and M. hyopneumoniae seropositivity in pigs fed high or low complexity nursery diet. This figure depicts the proportion of seropositivity to porcine reproductive and respiratory syndrome virus (PRRSV), influenza A virus (IAV), and Mycoplasma hyopneumoniae among pigs fed high or low complexity diet in seropositive groups. Note: 2, 9, and 4 groups were classified as seropositive for PRRSV, IAV, and M. hyopneumoniae, respectively. *p <  0.05