Effects of mycotoxins in pets
Mycotoxins can cause immunosuppression at levels that are undetectable by routine screening methodsProfessor Vincent Cheng
Bohn and Razzai-Fazeli concluded that dogs exposed to high amounts of aflatoxins, higher than 0.5 mg/kg BW, die within days showing signs like enlarged livers and hemorrhages.2 The authors reported that sub-acute doses (0.5-1 mg aflatoxin/kg pet food) caused symptoms like anorexia, lethargy, jaundice, intravascular coagulation and death within 2-3 weeks.2 Chronic exposure over 6-8 weeks produced liver damages as well.
Ergot alkaloids can contaminate a variety of grass species, including small grains. Ergotism is one of the oldest known mycotoxicoses. Already in the Middle Ages a disease called “St. Anthony’s Fire” was described from affected individuals as sensation of fire shooting from the tips of their appendages.10 Two types exist: gangrenous, like dermal lesions, and convulsive with effects on the central nervous system and also gastrointestinal effects, like nausea and vomiting.10
Fumonisins are of particular concern for rabbits. Rabbits exposed to 1.75 mg fumonisin B1 (FB1)/kg BW/day died due to renal and hepatic damages as well as leukoencephalomalacia.
Fusaric Acid (FA) has negative effects on dogs at relatively high doses. Immunotoxicity, hypotensive effects, vomiting and decreased weight gain were observed in a study where feed contaminated with 50 mg FA/kg BW was used.9
Dogs also showed high susceptibility to ochratoxin A (OTA).10 A single dose of 7.8 mg OTA/kg BW was lethal for young beagles. Similarly, exposure of the same animals to a daily dose of 0.2 mg OTA/kg BW, produced the same effects. Symptoms of OTA intoxication include anorexia, weight loss, vomiting, tenesmus, bloody diarrhea, increased body temperature, tonsillitis, dehydration and prostration.10
Cats and dogs are sensitive to trichothecenes. The effects of deoxynivalenol (DON) were studied at concentrations up to 4.5 mg DON/kg pet food and feed refusal was observed.8 Concentrations of DON up to 8 mg DON/kg pet food resulted in vomiting.8 Furthermore, the authors reported the ability of dogs to choose uncontaminated food, validating what was observed in other studies where DON was demonstrated to cross the blood-brain barrier.8
Trichothecenes: diacetoxyscirpenol (DAS)
The adverse effects of DAS were tested in dogs and high susceptibility towards this mycotoxin was observed. Symptoms like deformed blood cells, damages to bone marrow, gastrointestinal and immune dysfunctions were observed in the group that received the mycotoxin-contaminated food (0.5 mg DAS/kg BW).4 Cats were reported to be more resistant to trichothecenes, but information on clinical trials and dosage used was not found.
Both female and male dogs are sensitive to zearalenone (ZEN). In groups that were treated with 5 mg ZEN/kg BW for 13 weeks, effects like reduction of the endocrine ovary tissue (corpora lutea) and arrested spermatogenesis were observed.7 Although the dosage used in the aforementioned study is quite high, adverse effects like cell damages in ovaries, edema and hyperplasia in the uterus, were also observed at lower dosages (consumption of contaminated feed containing 200 ppb).5
- Boermans, H.J., Leung, M.C.K., Mycotoxins and the pet food industry: Toxicological evidence and risk assessment, International Journal of Food Microbiology (2007), doi:10.1016/j.ijfoodmicro.2007.07.063.
- Bohn, J., Razzai–Fazeli, E., 2005. Effects of mycotoxins on domestic pet species. In: Diaz, D. (Ed.), The Mycotoxin Blue Book. Nottingham University Press, Nottingham, UK, pp. 77–92.
- Bucci, T.J., Hansen, D.K., LaBorde, J.B., 1996. Leukoencephalomalacia and hemorrhage in the brain of rabbits gavaged with mycotoxin fumonisin B1. Nat. Toxins 4, 51–52.
- Coppock, R.W., Hoffmann, W.E., Gelberg, H.B., Bass, D., Buck, W.B., 1989. Hematologic changes induced by intravenous administration of diacetoxyscirpenol in pigs, dogs, and calves. Am. J. Vet. Res. 50, 411–415.
- Gajecka, M., Jakimiuk, E., Skorska-Wyszynska, E., Zielonka, L., Polak, M., Paluszewski, A., Rybarczyk, L., 2004b. Influence of zearalenone mycotoxicosis on selected immunological, haematological and biochemical indexes of blood plasma in bitches. Pol. J. Vet. Sci. 7, 175–180.
- Haschek,W.M., Voss, K.A., Beasley, V.R., 2002. Selected mycotoxins affecting animal and human health. In Handbook of Toxicologic Pathology, In: Haschek, W.M., Roussex, C.G., Wallig, M.A. (Eds.), 2nd ed. Academic Press, New York, NY, pp. 645–698.
- Hidy, P.H., Baldwin, R.S., Greasham, R.L., Keith, C.L., McMullen, J.R., 1977. Zearalenone and some derivatives: production and biological activities. Adv. Appl. Microbiol. 22, 59–82.
- Hughes,D.M.,Gahl,M.J.,Graham, C.H.,Grieb, S.L., 1999.Overt signs of toxicity to dogs and cats of dietary deoxynivalenol. J. Anim. Sci. 77, 693–700.
- Matsuzaki, M., Yoshida, A., Akutsu, S., Tsuchida, M., Okuyama, D., 1976a. Studies on toxicity of fusaric acid-Ca. IV. Chronic toxicity in dogs. Jpn. J. Antibiot. 29, 518–542.
- Szczech, G.M., Carlton,W.W., Tuite, J., 1973. Ochratoxicosis in Beagle dogs. I. Clinical and clinicopathological features. Vet. Pathol. 10, 135–154.