Porcine epidemic diarrhea (PED) is a disease caused by a virus in the Coronaviridae family that affects piglets more than adults. Mortality can be up to a 100% in lactating piglets. And causes diarrhea of different degrees, from semi-liquid to watery, in sows.

Several trials showed that piglets vaccinated against PED have a lower mortality rate. This is due to the lactogenic immunity obtained by piglets thanks to the ingestion of high-quality colostrum. For this reason, it is important to improve the immunogenic capacity of colostrum, which is evaluated by the IgA levels.

Objective

The objective of the trial was to assess whether the administration of immunostimulant pronutrients increases the levels of IgA (immunogenic capacity) of the colostrum in sows after they received two intramuscular vaccines against Porcine Epidemic Diarrhea (PED).

The effect of immunostimulant pronutrients was compared to a vaccination program based on the administration of an additional oral vaccine.

Methodology

Treatment groups

3 groups were formed:

• Control: composed of 15 sows that received 2 attenuated anti-PED vaccines intramuscularly, at days 40 and 20 prepartum.
• Immunostimulant pronutrients: consisting of 15 sows that received 2 attenuated anti-PED vaccines intramuscularly, at days 40 and 20 prepartum. In addition, immunostimulant pronutrients were included in the feed at 0.5 kg/ton.
• Extra vaccine: consisting of 11 sows that received 2 attenuated anti-PED vaccines intramuscularly, at days 40 and 20 prepartum. In addition, they received an attenuated oral anti-PED vaccine at day 15 prepartum.

IgA detection technique

• Colostrum samples were taken on the first day after delivery, sIgA concentration was evaluated using Elisa kits based on the optical density of the samples.
• Samples with an optical density (OD) greater than 0.4 were considered positive, which means they were able to protect piglets.
• 80% of the samples should be positive (high IgA concentration) for the groups of sows to be considered protected.

Results

Average OD in immunostimulant pronutrients groups was 0.925, 0.1028 in the control and 1.098 in the groups with an additional vaccine. Therefore, the control group was the only one that failed to obtain an average concentration of IgA in colostrum sufficient to protect piglets (0.4).

The lowest percentage of positive samples was obtained by the control group with 76% positives (insufficient), immunostimulant pronutrients group obtained 91.67% positive samples (enough to protect the litter, since it is higher than the 80%).

The groups that received an extra vaccine orally showed a percent of positives above 90%.

Conclusions

Immunostimulant pronutrients were able to significantly increase the concentration of s-IgA in colostrum and the percentage of positive results, which was 16% higher compared to the control group.

Immunostimulant pronutrients help to achieve sufficient level of protection against PED, while it was insufficient in vaccinated animals without supplementation, who obtained a percentage of positives below80%, which indicates low protection.

Immunostimulant pronutrients’ effect was equivalent to that of an additional oral vaccine, considering the percentage of positive sows. In addition, the administration of immunostimulant pronutrients requires less management than the oral vaccine.

In conclusion, immunostimulant pronutrients improve the immune response generated by vaccination in sows and, thanks to the IgA in colostrum, piglets will be more protected against PED.

Immunostimulant pronutrients are produced and marketed by Biovet S.A. under the name ALQUERNAT IMMUPLUS.