Effect of the appetite stimulant cyproheptadine on deoxynivalenol-induced reductions in feed consumption and weight gain in the mouse

Deoxynivalenol (DON, vomitoxin), a Fusarium mycotoxin, is suspected of inducing its anorectic/feed refusal activity through a serotoninergic (5HT) mechanism, possible via 5HT(2)-receptors. In this study the efficiency of cyproheptadine (CYP), a serotonin antagonist and known appetite stimulant, to attenuate the adverse effect of DON was investigated in mice. CYP was administered in the feed for two days before animals began receiving the DON, which was also added to the feed. Both agents were administered concurrently thereafter for a 12-day period. Dosing levels included various combinations of the two compounds, ranging from 0-16 ppm DON and 0-20 ppm CYP. Results showed that CYP could effectively offset the reduction in feed intake caused by dietary DON, but only when dose levels were optimized (CYP appeared to have a narrow effective dose range, which was also dependent on the DON concentration). In fact, optimum CYP doses were able to enhance feed intake in DON-fed mice above control levels, indicating that more than just a direct block of the toxin's effect was occurring. Conversely though, the effect of CYP on weight gain (WG) was ambiguous. At the lower CYP doses (less than or equal to 5 ppm), alone or in combination with the lowest DON level tested (4 ppm), a modest positive effect was noted, but at the higher DON concentrations (greater than or equal to 8 ppm) the overall WG generally remained depressed, and tended to be reduced further by increasing doses of CYP. These results provide additional support that serotoninergic mechanisms probably play a role in mediating DON-induced reduction in feed intake. Where and how DON actually initiates its anorectic effect, however, has not been resolved.