Edema or oedema, depending whether you are in the USA or UK,
respectively, is a frequent gastrointestinal disorder affecting millions of pigs
each year. Scours, loss of appetite, depressed performance and overall condition
are all consequences of this infective disease.
It is beyond the scope of this article to offer
veterinary advice. In contrast, the advice of a qualified practicing
veterinarian is strongly advocated in such cases. Nevertheless, a number of
nutritional intervention strategies are available to at least alleviate the
symptoms of this disease, if not completely prevent or cure it. It must be
emphasized here that not all such nutritional strategies work in every farm, so
their employment should be considered as part of a greater overall program
Most pathogenic bacteria, including Escherichia coli, feed on protein and
thus, it makes sense to offer them less of a substrate to proliferate. To this
end, the dietary protein levels may be dropped by 2-4%, keeping the amino acid
ideal profile. To the same effect, increasing dietary protein digestibility also
helps reduce undigested protein reaching the hindgut, because, increased
digestibility reduces dietary specifications for total levels of protein.
The use of zinc oxide, where allowed, at levels up to 3000 ppm of Zn in
complete feed has also been shown to help in most cases of pathogenic diarrhea.
It is best to gradually reduce its inclusion level to 2000 and then 1000ppm
throughout the nursery period to avoid depression of feed intake. Also, copper
sulfate, again where allowed, up to 250 ppm in complete feed is also beneficial
against scours, especially during the later stages of the nursery period. It has
also been shown that reducing the amount of calcium in the diet improves stomach
pH conditions, creating thus a less favorable environment for bacterial growth.
Finally, it is important to keep in mind that E. coli thrive on an iron-rich
substrate, and thus it might be beneficial to limit this nutrient to minimal
levels required for growth.
It is quite common knowledge the fact that reducing or removing soybean meal
from the piglet diets greatly reduces the incidence of gastrointestinal
infections, including edema disease. Although removal of soybean meal would
markedly increase feed cost, this is not completely unfeasible in the
post-weaning diets. Naturally, organic acids are also quite helpful against
bacteria growth as they tend to create an acidic environment throughout the
gastrointestinal tract, and especially in the stomach. In this end, blends of
organic acids are usually better than straight acids. There are also claims that
betaine might reduce the symptoms of diarrhea, acting as a strong osmotic
regulator, but for this I am prepared to review more data before I am thoroughly
Beyond the obvious suggestion of enhancing biosecurity, sanitation, and
overall animal housing conditions, there a couple less known strategies of
reducing diarrheas. First, limiting feed intake during the first four-five days
post-weaning is strongly advocated in cases of high infective stress as this
strategy reduces the amount of undigested feed reaching the hindgut. Also, the
use of coarsely ground cereals instead of fine ones, and only uncooked, has been
shown to further increase the overall health of the digestive tract in cases of
severe bacterial infections. Although these two intervention strategies are
quite powerful in controlling scours, they also limit animal performance, so
they should be employed with care.