Evaluation of subchronic dietary fumonisin B₁ on nutrient digestibility and growth performance of rats

Abstract

Fumonisin B₁ (FB₁), a toxin produced by Fusarium verticillioides (Fusarium moniliforme) and other Fusarium species which grow on maize worldwide, has been documented to cause various physiological responses in animals. Thirty-nine female Wistar rats randomly assigned to three treatment groups were used to assess the effects of dietary FB₁ on nutrient utilization and growth performance. Each group received one of the three diets containing 0.20, 10.0 and 20.0 mg FB₁/kg constituting diets 1, 2 and 3, respectively. The animals were weighed weekly and proximate chemical compositions of the diets and the faecal samples collected from the rats on each diet were determined using standard methods. Dietary FB₁ significantly (P < 0.05) influenced nutrient digestibility, feed intake, feed conversion efficiency and relative weight gain. Rats fed diets 2 and 3 had relative weight gains of 87.2 and 66.2% of the rats fed diet 1, respectively. Rats on diet 1 were about 104.5 and 160.6% more efficient in feed conversion compared to those on diets 2 and 3, respectively. Dietary exposure to FB₁ at a concentration of about 10 mg/kg or higher for a period of 35 days is a potential health risk that reduced nutrient utilization by adversely affecting proper nutrient digestion, absorption and/or metabolism, resulting in poor growth rates in Wistar rats. This study revealed that adverse effects of FB₁ on nutrient digestibility and utilization play a significant contributory role in poor growth performance usually associated with animals exposed to diets containing FB₁.

Key words: Fumonisin B₁, growth performance, mycotoxin, nutrient digestibility, rats.