Distinct effects of equal levels of Fusarium toxins (Deoxynivalenol) in growing pigs. Possible reasons.

The mycotoxin deoxynivalenol (DON, vomitoxin) is well documented to cause reduced feed consumption (FC) and weight gain (WG) rates in sensitive animal species (e.g. swine). In establishing feeding guidelines and diagnoses of mycotoxin related diseases it is important to establish a "dose and response" factor-but a simple relationship is not always present for DON and other Fusarium toxins. Possible reasons for these findings (e.g. experimental design and/or role of toxin source) are discussed with reference to previous research.

Deoxynivalenol in pigs: An exclusive effect on the appetite?

A feeding-trial was conducted to determine the effects of a deoxynivalenol (DON)-contaminated diet in growing pigs. DON was added as either the purified toxin or as naturally contaminated wheat. Growth performance, biochemical and hematological parameters and DON-transformation through intestinal bacteria were monitored throughout the study. Epithelial tissues along the gastro-intestinal tract were also examined for pathological changes and selected enzyme activities (oxoglutarat dehydrogenase, alanine-amino-transferase). There were no differences among the dietary treatments in all parameters measured except for feed intake and weight gain in the naturally contaminated diets fed ad libitum. Effectsin vivo could not be explained exclusively by cytotoxicity of DON foundin vitro. These observations may reflect the presence of other unidentified (toxic) compounds in the naturally contaminated grain or the influence of further factors. In future studies synergistic/additive interactions with substances promoting appetite should be taken into consideration.

[Not Available]. / Wirkung von Deoxynivalenol (DON) auf den Magen-Darm-Trakt männlicher Läuferschweine.

Following an experiment feeding Deoxynivalenol to growing pigs histological studies have been carried out to evaluate tissue damaging effects of DON. Pigs were fed with naturally contaminated wheat containing 4000 and 6000 µg DON/kg feed. A number of two animals was chosen from control and high exposed group, respectively. Samples of the gastrointestinal tract, liver and kidney were examined. Although, clear effects in feed consumption and weight gain could be realized, only one animal from the high exposed group showed focal alterations in tissues of the gastrointestinal tract.

[Not Available]. / Transformation von Deoxynivalenol durch die Darmflora des Schweines - In-vitro Untersuchungen zur Adaptation in Abhängigkeit von der Darreichungsform.

To examine the biotransformation of Deoxynivalenol (DON) by the normal gut flora of pigs (in reliance on toxin-source) an in-vitro system was established. Suspensions of rectum contents from different treated animals were incubated with pure DON. Despite fast adaptation of microflora (Deepoxidation of DON) of animals fed wheat diet, no effects on reduced feed consumption and weight gain were seen. Even fast adaptation of microflora (lower intestine) couldn't avoid DON-effects in vivo.

[Not Available]. / Wirkung von Deoxynivalenol beim wachsenden Schwein in Abhängigkeit von der Darreichungsform.

To evaluate the minimum effective dose of pure DON leading to measurable losses in weight gain and feed consumption a special feeding experiment was created to compare the effect of DON in natural contaminated wheat and - for the first time - a non-cereal diet (potato) spiked with pure DON. Examined parameters were weight gain, feed consumption and blood parameters.Three trials were conducted. In the first trial a concentration of 4000 µg DON/kg feed was used. In the second and third trial we used concentrations of 4000 and 6000 µg DON/kg feed. Severe effects on feed consumption and weight gain were found only in the second trial (naturally contaminated wheat ad lib.). By contrast, no differences in any parameter were found in the first (restricted feeding) and third trial (non-cereal diet spiked with pure DON ad lib.).