The worldwide focus on fumonisins

Author: Radka Borutova DVM, PhD, Business Development manager, Nutriad International

The discovery of fumonisins is well described in the publication by Marasas, 2001. According to Marasas, the predominant fungus isolated from moldy corn implicated in a field outbreak of equine leukoencephalomalacia (ELEM) in South Africa in 1970 was Fusarium verticillioides (F. moniliforme). The same fungus was also prevalent in moldy home-grown corn consumed by people in high-incidence areas of esophageal cancer (EC) in the Transkei region of South Africa. Culture material on corn of F. verticillioides strain MRC 826, which was isolated from moldy corn in Transkei, was shown to cause ELEM in horses, porcine pulmonary edema (PPE) syndrome in pigs, and liver cancer in rats. A short-term cancer initiation/promotion assay in rat liver was used to purify the carcinogen(s) in the culture material. These efforts finally met with success when fumonisins B1 and B2, novel mycotoxins with cancer-promoting activity in rat liver, were isolated from culture material of F. verticillioides MRC 826. Following the identification of the chemical structure of the fumonisins, these carcinogenic mycotoxins were shown to occur naturally in moldy corn in Transkei. Shortly thereafter, high levels of fumonisins in the 1989 U.S. corn crop resulted in large-scale field outbreaks of ELEM and PPE in horses and pigs, respectively, in the United States. Subsequently, the fumonisins were found to occur naturally in corn worldwide, including corn consumed as the staple diet by people at high risk for EC in Transkei and China. These findings, together with the fact that the fumonisins cause field outbreaks of mycotoxicoses in animals, are carcinogenic in rats, and disrupt sphingolipid metabolism, resulted in lot of worldwide interest in these compounds during the first 10 years after the discovery of the fumonisins in 1988.

UNIKE®PLUS efficacy against fumonisins in broiler chicks

The objective of the experiment was to evaluate the efficacy of the complex mycotoxin deactivator UNIKE® Plus in reducing the toxic effects of fumonisins added to broiler diets from hatch to day 21.

600 birds were randomly allocated into five treatment groups with 12 replicates each and with 10 birds in each group. The experiment lasted 21 days. Dietary treatments included:

Control:                                    good quality feed, no product

UNIKE®PLUS:                              good quality feed + 5 kg/t UNIKE®PLUS

Mycotoxins:                                feed contaminated with 100 ppm of fumonisins

Mycotoxins+2,5 kg/t UNIKE®Plus:   contaminated feed with 2,5 kg/t UNIKE®Plus

Mycotoxins+5 kg/t UNIKE®Plus:      contaminated feed with 5 kg/t UNIKE®Plus

The typical management of birds reared in battery cages was used with feed and water offered ad libitum. The feed was contaminated with a mycotoxin culture material (96% fumonisin B1, 4% fumonisin B2). The parameters measured were: individual body weight, feed intake and feed conversion ratio (FCR) and individual relative weight of carcass dressing (expressed as percentage). Data was analysed by analysis of variance (ANOVA) and the Bonferroni test (p<0.05) was used to compare the means.

Fig. 1 shows that both weight and FCR were lowest in birds fed the diet containing fumonisins. At the end of the experiment, the average body weight and FCR of the broilers which received fumonisins and UNIKE®Plus (2,5 and 5 kg/t) were significantly higher than the broilers which received fumonisins without mycotoxin deactivator in feed. Both dosages of UNIKE®Plus used in the experiment resulted in approximately 50% recovery of the performance losses caused by a very high level of fumonisins.

art 2 fig 1

Fumonisins in the feed resulted in increased relative liver weight (Table 1). The inclusion of UNIKE®Plus at both dosages significantly reduced relative liver weight compared to the birds which received fumonisins without product.

The mode of action of fumonisins is primarily explained by the interference with the de novo synthesis of complex glyco-sphingolipids. As a consequence, Free sphingoid bases (sphinganine and sphingosine) are toxic to most cells accumulate in tissues, which results in disturbances of cellular processes such as cell growth, cell differentiation, and cell morphology, endothelial cell permeability and apoptosis, leading to detrimental hepato and nephrotoxic effects. The accumulation of sphinganine and sphingosine in the serum and urine is a useful biomarker for the exposure of fumonisins.

The ratio between sphingolipids (Sa/So) was higher in chickens fed fumonisins (Table 1). The inclusion of UNIKE®Plus in contaminated diets caused a reduction of this ratio and a dose effect was observed. The inclusion of 5 kg/t of UNIKE®Plus reduced Sa/So by 37.8% and this was statistically significant compared to birds that received fumonisin-contaminated fed without product.

art 2 table 1

This experiment demonstrated that the presence of 100 ppm fumonisins in the diet caused adverse effects on the growth performance and other health parameters of broiler chickens. The evaluated parameters in this experiment showed significant protective effects of UNIKE®Plus either at 2,5 or 5 kg/t. The results of this experiment indicate that continuous, specific, effective counteraction and control of mycotoxins offers an opportunity to significantly improve animal health, performance, productivity and profit.

 

Published on Nutriad website 08/05/18.