Nutritional_solutions_for_edema_disease

Nutritional solutions for edema disease
Edema disease is a common, yet sporadic, gastrointestinal disorder affecting millions pigl worldwide each year. This disease affects the nervous system, while major symptoms usually include puffy eyelids, occasional diarrheas, lameness, loss of appetite, depressed performance, rough appearance, and high mortality.
Veterinary preventive intervention and a high level of health status throughout all farm operations is required to reduce the occurence of edema disease. Nevertheless, even under the best veterinary care and management conditions, edema still emerges in many farms, worldwide. In such cases, nutrition can also play a significant role in alleviating the symptoms, if not completely preventing the disease.
Edema diseased is thought to be triggered by certain serotypes of Escherichia coli bacteria, and as such, any nutritional remedy effective against colibacteria are usually also quite effective against serotypes causing edema disease.
Antibiotics and Zinc Oxide Ban
Edema disease is more prevalent in those areas of the world where antibiotics and
other antimicrobial agents (including zinc oxide) have been banned, such as is the case
in the European Union. In fact, piglets imported from Denmark to be finished in
Germany usually arrive without any symptoms. But, as soon as they settle in Germany
farms, they quickly break down with edema disease, something that does not
happenin Denmark when pigs from the same farms are transferred to finishing
facilities there. This has been attributed by many field experts to the lack of zinc oxide
in German piglet diets, due to a ban of this ingredient in Germany. Thus, where
allowed, zinc oxide is considered a good supplement to be used against edema disease.
Specific Antibiotics
In a recent study in Denmark 27 isolates of Escherichia coli O139, which triggered
edema, were evaluated against their resistance to well-known antibiotics. All 27
isolates were sensitive to colistin, gentamicin, apramycin and amoxicillin/clavulanic
acid. Resistance to sulphonamide was found in 80% of the isolates. Thus, in many areas
of the world where antibiotics are still allowed, their use greatly helps against the
occasional flare up of edema. The correct antibiotic to be used should be left at the
discretion of the attending veterinarian.
Dietary Protein
Pathogenic bacteria, including Escherichia coli, feed on protein and thus, it makes
sense to offer them less protein to proliferate. To this end, the dietary protein level in
diets for piglets suffering from edema disease should be lowered by 4 percentage
points (but not less than 18% in the diet), while rebalancing the amino acid profile. To
the same effect, increasing dietary protein digestibility also helps reduce undigested
protein reaching the hind gut. Alternatively, a lower-density diet may be offered but
this might also result in depressed performance due to lack of nutrients for growth and
development. In this case, the least worst case scenario should be weighed against financial losses.
Copper, Calcium, and Iron
Apart from zinc oxide, a high dosage of copper sulfate can also beneficial against
bacterial infections, especially during the later stages of the nursery period. It has also
been shown that reducing the amount of calcium in the diet (for example a maximum
of 0.8% Ca in the first post-weaning diet is recommended) improves stomach pH
conditions, creating thus a less favorable environment for bacterial growth. Finally, it is
important to keep in mind that Escherichia coli thrive on an iron-rich substrate, and
thus it might be beneficial to limit this nutrient to minimal levels required for growth.
 
Soya, Organic Acids, and Extracts
Reducing or removing soybean meal from piglet diets greatly reduces the incidence of
gastrointestinal disorders, including edema disease. Although replacing soybean meal
with other more digestible protein sources markedly increases feed cost, this is strongly
recommended in the case of piglets suffering from edema disease. Organic acids and
perhaps some plant extracts are also quite helpful against bacteria as they tend to
create an environment unsuitable for bacterial growth throughout the gastrointestinal
tract, and especially in the stomach. In this end, blends of organic acids with or without
plant extracts are usually better than straight acids.
Enteric Acidocis
Dutch researchers recently examined affected and healthy pigs from the same herd and
concluded that although edema disease is closely associated with the presence of
Escherichia coli, dietary factors usually contribute or aggravate this disorder. Affected
pigs in this study exhibited symptoms of metabolic acidosis, evidenced by higher
blood and intestinal acidity. It was speculated that toxins produced by Escherichia coli
in the gastrointestinal tract had a greater chance to cross the intestinal barrier in pigs
suffering from metabolic acidosis, because increased intestinal acidity is associated
with increased permeability. Therefore, nutritional intervention strategies in the face of
edema disease outbreak may be beneficial. To this cause, optimal dietary electrolyte
balance (Na+K-Cl) for diseased piglets may be different than that for healthy piglets,
because a higher dietary electrolyte balance may prevent metabolic acidosis.
Feed management
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 hind gut. 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. In addition, feed in meal form is preferable
to pelleted feed when pigs are known to suffer from enteric diseases. Although these
intervention strategies are quite effective in controlling gastrointestinal disorders, they
also have the potential of limiting animal performance, and as such they should be
employed with care.
Fiber
Based on empirical evidence, increasing dietary crude fiber by 2-3 percentage points
has been shown to help against many types of bacterial infections. To increase dietary
fiber, barley and oats, are quite effective while being more nutritive than other sources
of fiber. Similarly, beet pulp has been effective in many cases, but not always, for unknown reasons. Other sources of purified fibers have shown mixed results so far, but research is ongoing in this area.
Egg Immunoglobulins
This is the latest technology of addressing edema disease and it is in fact the only direct
intervention method. Immunoglobulins are obtained from eggs that have been
produced by hens hyper-immunized against strains of piglet-specific strains of
Escherichia coli known to trigger edema disease. These immunoglobulins are then
added directly in the piglet feed and once ingested reach the gastrointestinal tract.
There, they bind on the specific strains of colibacteria for which they have been
produced against, rendering them virtually ineffective.
A recent trial evaluated the use of egg immunoglobulins in a farm with strong problems of edema disease. Results (Figure 1) suggested that pigs fed with egg immunoglobulins specific against edema disease were about 2.5 kg heavier at 68 days post-weaning, while mortality was just above 5% compared to 10% in piglets fed diets without this supplement. Furthermore, treatment cost for medicines was significantly reduced.
FIGURE 1
Piglets fed egg immunoglobulins fared better under an edema disease attack.
(Data courtesy of EW Nutrition GmbH, Germany).
Immunoglobulins
Conclusions
Edema disease is not an easy problem. Apart from veterinary care and enhance
biosecurity protocols, nutritional intervention remedies are frequently employed to
alleviate the symptoms. Naturally, not all such measures are equally effective in every
farm. Depending on current feed formulations, certain nutrient changes and additives
can be of substantial help.

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