Effects of Dietary Protein and Intestinal Microflora on Excretion of Amino Acids in Poultry

The effects of dietary protein and intestinal microflora on amino acid excretion by poultry were investigated. Adult roosters were force-fed casein, gelatin, corn gluten meal, or feather meal either as the sole dietary component or with a corn starch and cellulose mixture. Excreta were collected quantitatively for 12, 24, and 48 hr after feeding. Average digestibility of amino acids in casein, gelatin, and corn gluten meal was 96% and that of feather meal was 82%. The average digestibility of amino acids in feather meal was approximately 3% lower for a 48-hr than a 24-hr excreta collection period. All protein sources significantly (P<.05) affected the amino acid composition of excreta during 12 hr postfeeding. Feather meal also significantly (P<.05) affected amino acid composition of excreta after 24 hr postfeeding, indicating that more than 24 hr were required for complete intestinal clearance of undigested amino acids. Corn starch and cellulose had no effect on digestibility of amino acids.