Metabolism and Nutrition : Nutrition - Feeds and Manufacturing

An experiment was conducted to evaluate marker selection and mix time on mix uniformity in the feed manufacturing process as determined by percent coeffi cient of variation (% CV). A corn-soybean meal based diet was formulated for broiler chicks from d 0 to 17. Dietary nutrients or tracers evaluated included: 1) salt (chloride ion); 2) phosphorus; 3) manganese; 4) iron particles (Micro TracerTM Red #40 by count)(MTC); 5) iron particles (Micro TracerTM Red #40 by absorbance)(MTA); 6) iron particles (Micro TracerTM RF Blue Lake)(MTB); 7) roxarsone; 8) semduramicin; 9) DL-Methionine; 10) HCl-Lysine; and 11) crude protein. Diets were mixed with a double ribbon mixer for three different mix times (0.5, 2.5, and 5.0 min). Ingredients were weighed separately and added in the same location for all treatments. Following the mix cycle, feed was conveyed to a sacking bin by a discharge screw and bucket elevator. Samples (5 kg) were collected from 10 sacks (i.e. 1,3,5, etc.) for % CV calculation. Within each sample, all markers were analyzed for that particular batch. With the exception of protein and MTA, all marker data reported a considerable reduction in % CV as a percent, ranging from 17.3% (roxarsone) to 52.9% (phosphorus) from 0.5 to 2.5 minute mix time. From 2.5 to 5.0 minutes, salt, roxarsone, and MTC, % CV increased, while all other markers continued to reduce in % CV. Overall, from 0.5 to 5.0 minutes all markers showed a reduction in % CV however, crude protein should not be considered as a marker due to all major components contribute some level of protein and can be diffi cult to determine if the batch has been mixed adequately.