Using egg immunoglobulins to enhance piglet survivability

The number of healthy piglets weaned is the most important factor for the calculation of profit in piglet production, so it has to be pursued as high as possible.

Enhancing immune status during the first days of life is the key for survival in piglets. | Photo: Thorsten Schmidtkord

Losses in the farrowing unit normally occur during the first seven days of life as piglets are born with nearly no immune protection. The intake of immunoglobulins out of colostrum therefore is of vital importance. Besides cleanliness and special feeding, piglet survival can be enhanced by two additional strategies that support the effect of colostrum: a direct one, meaning the application of immunoglobulins (IgY from eggs) to piglets and supporting the immune system in the gut, or an indirect one, meaning supply of IgY to the sow and therefore keeping the pathogenic pressure in the farrowing unit as low as possible.

Piglets are born with no immune protection and scarce energy reserves

It is clear that piglets are physiologically immature at birth. Their energy reserves are scarce at approximately 1 to 2 percent of body fat, with the main part of it structural and subcutaneous. Therefore, in the first hours of life they mostly count on the glucose supply out of glycogen from the liver as a main source, but this is only enough to cover their needs for a few hours.

Due to the construction of the sow’s placenta, a transfer of immunoglobulins (antibodies) within the womb is not possible. The piglets are born with practically no immune protection and depend on the immediate intake of immunoglobulins out of colostrum. The immunoglobulins can be absorbed in the gastrointestinal tract and immediately transferred into the bloodstream — but also only for a short time. The absorption ability of the piglets starts to decrease soon after birth and ends after 24 to 36 hours.

Strategy 1: Keeping pathogenic pressure in the farrowing unit as low as possible

Regarding the preconditions, it is clear that the farrowing unit has to provide as much comfort for the piglets as possible. It has to be warm: low temperature promotes hypoglycemia, and the piglets looking for heating nearby the sow can get crushed. It has to be clean, and the pathogenic pressure has to be as low as possible: a low immune status makes the piglets susceptible to pathogens like E. coli, Clostridium perfringens and rotavirus, all causing diarrhea. Concerning these requests, the first two measures would be cleaning of the farrowing unit and heating. As the demand for heating is different in sows and piglets, a piglet nest with a special heat lamp is recommended.

Relating to the pathogenic pressure, things are more complicated, as most of the pathogens are provided by the sow excreting them together with the feces. Therefore, strategy must be to keep the amount of pathogens possibly excreted by the sow as low as possible or to “inactivate” these pathogens and make them harmless for the piglets. The first one could be achieved by vaccination of the sow: the sow produces immunoglobulins against the pathogens and fights them. An additional advantage: the vaccination also positively influences the content of immunoglobulins in the colostrum.

The second one could be reached by feeding natural ingredients like probiotics. The aim is to control enteric pathogens and to strengthen the immune system, especially locally in the gut. The main mode of action consists of improving intestinal health by decreasing the population of potentially harmful microorganisms such as E. coli, Salmonella, and Clostridium. Favoring the multiplication of good microbes like Lactobacilli and Bifidobacteria is one possibility. They compete with harmful pathogens for nutrients and binding sites and prevent them from multiplying. Another one is the administration of egg immunoglobulins (IgY) to the sow through her feed. The egg immunoglobulins bind to the pathogens within the intestinal tract. In this complex the pathogens are no longer active, and this harmless form can be ingested by piglets without danger.

Strategy 2: Supporting piglets directly with administration of immunoglobulins

The aim is to strengthen the local immunity in the gastrointestinal tract by increasing the amount of immunoglobulins (Ig), which are highly effective defensive cells, and therefore to help the piglets on fighting with different pathogens. The main and most important source of Ig is the sow colostrum. As already mentioned, the content of specific immunoglobulins (IgG) in the colostrum can be increased, for instance, by vaccination of the sow. Another possibility is to orally supply egg immunoglobulins (IgY) directly to the piglets. This is usually achieved with a syringe without needle or special oral doser. Both classes of immunoglobulins (IgG from mammals, and IgY from birds) can bind to harmful germs in the gut, preventing the binding to the intestinal wall and reducing the incidence of diarrhea. The difference is in the degree of effectiveness and specificity.

Success comes from supporting piglets

Since the success of a piglet-producing farm stands and falls with the number of healthy piglets weaned, it is important to support the piglets best during the critical periods at the beginning of their life. As the immune status of the piglets is a precondition possibly leading to disease and losses, this problem should be one of the first to be targeted. The supply of the piglets with immunoglobulins, whether out of sow’s colostrum or from eggs, is a “direct” possibility. The other "indirect” alternative is to keep the pathogenic pressure in the farrowing unit as low as possible. Besides hygiene, it is important to aim for measures supporting the reduction of pathogens excreted by the sow. This reduction could be achieved by vaccination to promote the immune system of the sow fighting against the pathogens or by the administration of egg immunoglobulins, which bind the pathogens in the gut and make them harmless for the piglets.