Effect of cleaning corn on mycotoxin concentration and nursery pig growth performance.

Mycotoxins are naturally produced hazards that result from molds grown on cereal grains and other commodities. These molds may produce carcinogenic mycotoxins, which can be harmful to humans and animals. Removing broken kernels has been demonstrated to reduce mycotoxin concentration, but with high variability. Therefore, two experiments were conducted to quantify the magnitude of natural mycotoxin concentration that may be reduced by cleaning corn. Two loads of corn that were naturally contaminated with mycotoxins were procured. Corn for Experiment 1 was contaminated with aflatoxin (1,074 parts per billion; ppb), fumonisin (8.3 parts per million; ppm), and ochratoxin A (206 ppb), while corn for Experiment 2 was contaminated with only fumonisin (5.5 ppm). Corn was cleaned by mechanical sieving. For each experiment, corn was divided into twenty 150 kg runs. Runs were randomly assigned to 1 of 4 experimental treatments: 1) no screen 2) 12.7 mm screen, 3) 4.8 mm screen, and 4) 12.7 + 4.8-mm screen. The corn cleaner was sanitized between runs. Three 5 kg corn samples were collected from each run, and analyzed for mycotoxin concentration. In Experiment 1, cleaning reduced (P < 0.05) aflatoxin and fumonisin concentration by an average of 26% and 45%, respectively, compared to the original uncleaned corn level, but did not impact (P > 0.10) ochratoxin A. The resultant screenings had nearly four times the aflatoxin (4,224 ppb) and 7.5 times the fumonisin concentration (60.4 ppm) as the uncleaned corn. In Experiment 2, cleaning reduced (P < 0.05) fumonisin concentration by 32%. The resultant screenings had 19.6 times the fumonisin concentration (65.4 ppm) as the uncleaned corn. To determine the effect that cleaning corn may have on nursery pig growth performance, 360 nursery pigs were used in Experiment 3 to evaluate the impact of cleaning or pelleting on growth performance. Treatments were arranged in a 2 × 3 factorial with corn type (uncleaned vs. cleaned) and feed form (mash vs. pelleted from either mill A or B). Neither cleaning corn nor pellet mill type affected (P > 0.19) nursery pig growth performance. Pelleting improved (P < 0.0001) gain to feed ratio (G:F) by 7.6% compared to mash diets. These data suggest that cleaning is an effective method to legally reduce aflatoxin and fumonisin concentration, but does not impact animal growth performance. Screenings should be used cautiously when feeding to animals.