Facing a global trend in reducing the use of antibiotics for veterinary use, one of the most important disease control strategies is vaccine prophylaxis. Therefore, the efficacy of vaccine plans has become essential for the pig industry in recent years.

There is a wide range of vaccines available worldwide for bacterial and viral diseases: ileitis, enzootic pneumonia, colibacillosis, PRRS, PCV2, Aujezsky, parvo, porcine pleuropneumonia and swine flu are some of the main vaccines routinely used in pig farms.

However, the immune response that results after the application of these vaccines does not only depend on factors intrinsic to the vaccine, such as quality, manufacturer, storage conditions, application, etc. but also on the immunological state of the animal, individually or collectively.

There are numerous factors that can affect the immunity of the pig. Most of the time they appear in young animals, due to stress problems, parasitic or allergic diseases, secondary or acquired immunodeficiencies, use of certain drugs such as corticosteroids and some antibiotics, among others. An example would be the efficacy of vaccination against mycoplasma, which may be altered in the presence of PRRS virus or porcine circovirus type 2 (PCV2). These factors will lead to an immune hyporesponse due to impaired immune function of lymphoid cells and organs, even when no apparent clinical signs appear.

Avoiding vaccination failure

One of the answers to this challenge that the swine industry is facing is the use of additives applied to feed, specifically pronutrients.

Gordon Rosen defined the concept of pronutrient, back in 1950, as a “micro-ingredient included in feed in relatively small quantities whose mission is to improve animal physiology and intrinsic nutritional value and avoid the presence of pathogens.”

Its mechanism of action lies in the induction of certain genes in target cells that will cause an increase in synthesis of functional proteins that are involved in physiological processes and will improve animal health. Therefore, they do not have pharmacological action, do not generate waste, resistance or require waiting periods and can be an adequate alternative to the prophylactic use of antibiotics.

The pronutrients can be classified according to their organ or target tissue: conditioners and optimizers of the intestinal mucosa, immunostimulants, liver conditioners, promoters of mineral absorption, etc.

For instance, the use of immunostimulant pronutrients in the diet of animals will activate the immune cells and tissues responsible for the response after vaccination.

It has been proven that the use of these pronutrients in the diet after several days prior to vaccination significantly increases the antibody titers of vaccines such as mycoplasma and influenza and, consequently, the level of individual and collective protection of the farm.

Below is one of the studies that tests the efficacy of immunostimulant pronutrients.

Analysis of the efficacy of immunostimulant pronutrients in pigs vaccinated with influenza and Mycoplasma vaccines

Introduction

This study, conducted at the University of Purdue (United States), aimed to evaluate the effect of immunostimulant pronutrients in the improvement of the immune response, when vaccinated against the Swine Influenza Virus (SIV) and Mycoplasma spp., by analyzing the productive parameters (weight) and the antibody titer.

Methodology

In this trial, weaned piglets at 21 days were used, and the duration of the project was 42 days.

The animals were separated in 4 batches: the first two batches were not vaccinated, the first was fed only a basal diet, and the second, the diet combined with immunostimulant pronutrients. The third and fourth batches were vaccinated, and only one of them included immunostimulant pronutrients (fourth batch). (See table 1, for experimental design.)

Results

It can be highlighted that there were differences regarding the antibody titer between the two vaccinated study lots. On day 21 of the study, only the batch receiving vaccination + immunostimulant pronutrients was protected against Mycoplasma spp. and on day 42 of the trial, both diseases improved their antibody titer (9% in influenza and 57% in Mycoplasma).

In the case of Influenza, 40% more animals appeared with positive antibody titers, that is, they are more protected against the disease in the batch that received immunostimulant pronutrients, than in the batch that was only vaccinated (see graphic 1).

No significant differences were observed between the different groups, with respect to the productive parameters.

Conclusions

Although the daily weight gain was not significantly affected, the use of pronutrients in the diet did influence the antibody titer: it increased the production of specific antibodies against micoplasmosis and influenza in vaccinated pigs, which leads to greater resistance to these diseases.

As we have seen, vaccinations of certain diseases, that may be critical for the performance of the swine operation, may not be effective for several reasons, including the lack of an immune response. It has been proven that immunostimulant pronutrients can help to achieve an effective immune response and therefore a good health status on the farm. In addition to this, they can decrease the mortality rate, do not require withdrawal period and operate at very small doses.

In a global context, where reducing the use of antimicrobial therapies is becoming more important and the search for preventive measures increases, immunostimulant pronutrients play an essential role.

The immunostimulatory pronutrients, manufactured by Biovet S.A, are marketed as Alquernat Immuplus.