Effects of inorganic adsorbents and cyclopiazonic acid in broiler chickens

Previous studies with cyclopiazonic acid (CPA) have indicated that this mycotoxin strongly adsorbs onto the surface of a naturally acidic phyllosilicate clay (AC). The objective of this study was to determine whether AC (and similar adsorbents) could protect against the toxicity of CPA in vivo. Acidic phyllosilicate clay, neutral phyllosilicate clay (NC, or hydrated sodium calcium aluminosilicate), and a common zeolite (CZ, or clinoptilolite) were evaluated. One-day-old broiler chicks consumed diets containing 0 or 45 mg/kg CPA alone or in combination with 1% AC, NC, or CZ ad libitum from Day 1 to 21. Body weight, feed consumption, feed:gain, hematology, serum biochemical values, and enzyme activities were evaluated. Compared to controls, CPA alone reduced body weight at Day 21 by a total of 26% and resulted in a significantly higher feed:gain ratio. Toxicity of CPA was also expressed through increased relative weights of kidney, proventriculus, and gizzard. Also, there were some alterations in hematology, serum biochemical values, and enzyme activities. Treatment with inorganic adsorbents did not effectively diminish the growth-inhibitory effects of CPA or the increased weights of organs, although there was some protection from hematological, serum biochemical, and enzymatic changes produced by CPA. The results of this study suggest that in vitro binding of CPA to clay does not accurately forecast its efficacy in vivo; the reasons for this discrepancy are not clear, but they may be related to differences in clay binding capacity and ligand selectivity for CPA in vitro vs in vivo. Predictions about the ability of inorganic adsorbents to protect chickens from the adverse effects of mycotoxins should be approached with caution and should be confirmed in vivo, paying particular attention to the potential for nutrient interactions.