EFFECTS OF INORGANIC ADSORBENTS AND CYCLOPIAZONIC ACID IN BROILER-CHICKENS

Previous studies with cyclopiazonic acid (CPA) have indicated that thi s mycotoxin strongly adsorbs onto the surface of a naturally acidic ph yllosilicate clay (AC). The objective of this study was to determine w hether AC (and similar adsorbents) could protect against the toxicity of CPA in vivo. Acidic phyllosilicate clay, neutral phyllosilicate cla y (NC, or hydrated sodium calcium aluminosilicate), and a common zeoli te (CZ, or clinoptilolite) were evaluated. One-day-old broiler chicks consumed diets containing 0 or 45 mg/kg CPA alone or in combination wi th 1% AC, NC, or CZ ad libitum from Day 1 to 21. Body weight, feed con sumption, feed:gain, hematology, serum biochemical values, and enzyme activities were evaluated. Compared to controls, CPA alone reduced bod y weight at Day 21 by a total of 26% and resulted in a significantly h igher feed:gain ratio. Toxicity of CPA was also expressed through incr eased relative weights of kidney, proventriculus, and gizzard. Also, t here were some alterations in hematology, serum biochemical values, an d enzyme activities. Treatment with inorganic adsorbents did not effec tively diminish the growth-inhibitory effects of CPA or the increased weights of organs, although there was some protection from hematologic al, serum biochemical, and enzymatic changes produced by CPA. The resu lts of this study suggest that in vitro binding of CPA to clay does no t accurately forecast its efficacy in vivo; the reasons for this discr epancy are not clear, but they may be related to differences in clay b inding capacity and ligand selectivity for CPA in vitro vs in vivo. Pr edictions about the ability of inorganic adsorbents to protect chicken s from the adverse effects of mycotoxins should be approached with cau tion and should be confirmed in vivo, paying particular attention to t he potential for nutrient interactions.