Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/8/2003
Publication Date: 6/20/2004
Citation: Pimpukdee, K., Kubena, L.F., Bailey, C.A., Huebner, H.J., Afriyie-Gyawu, E., Phillips, T.D. 2004. Aflatoxin-induced toxicity and depletion of hepatic vitamin A in young broiler chicks: Protection of chicks in the presence of low levels of NovaSil Plus in the diet. Poultry Science. 83:737-744. Interpretive Summary: Mycotoxins are poisons produced by some fungi. Aflatoxin is a mycotoxin that is toxic to poultry and livestock and can occur as a natural contaminant of feedstuffs, which may then be used to feed poultry and livestock. The purpose of the present study was to evaluate NovaSil PLUS**TM (NSP), a calcium montmorillonite clay that is commonly used as an anticaking agent in feeds, for its ability to bind aflatoxin in test tubes and to prevent the toxic effects of aflatoxin on performance and vitamin A depletion in the liver of live broiler chicks. The results show that aflatoxin was tightly bound to the surface of NSP in test tubes and NSP in the diet protected chicks from the effects of high-level exposure to aflatoxin (5 parts per million) and preserved liver vitamin A levels when included in the diet at 0.50, 0.25, or 0.125 %. This is important because clay-based products may be used to block or reduce aflatoxin exposure, associated risks, and toxic residues in food of animal origin.
Technical Abstract: Aflatoxin contamination of foods and livestock feeds is an ongoing problem. In this research, NOVASIL PLUS**TM (NSP), a calcium montmorillonite clay that is commonly used as an anticaking agent in feeds, was evaluated for its ability to bind aflatoxin B1 (AfB1) in vitro and to prevent the onset of aflatoxicosis and vitamin A depletion in broiler chicks in vivo. Isothermal analyses were conducted with NSP and AfB1 to quantitate and characterize critical sorption parameters at equilibrium, i.e., ligand saturation capacities, affinity constants, thermodynamics of the sorption process. In vitro results indicated that AfB1 was tightly sorbed onto the surface of NSP which provided a high capacity and high affinity for the ligand. Thermodynamics favored sorption of AfB1 to NSP. The process was exothermic and spontaneous with a mean heat of sorption equal to approximately -50 kJ/mol, suggesting chemisorption (or tight binding). In addition to the in vitro studies, the effectiveness of NSP as an aflatoxin enterosorbent to attenuate the onset of aflatoxicosis in broiler chicks, was determined at three different inclusion levels in the diet (0.5%, 0.25%, and 0.125%). NSP alone was not toxic to chicks at a level as high as 0.5% in the total diets (based on body and organ weights, feed intake, and hepatic vitamin A levels). NSP in the diet significantly protected chicks from the effects of high level exposure to aflatoxins (i.e., 5 mg/kg) and preserved hepatic vitamin A levels, even at lower dietary intake of clay.