Quantitative Studies of Amino Acid Flow in the Digestive Tract of Sheep Fed Alfalfa Protein Concentrates

Mature wethers fitted with duodenal and ileal cannulae were fed isonitrogenous and isoenergetic diets containing alfalfa protein concentrate (APC) prepared by various methods. Amino acid concentrations in digesta at the proximal duodenum and distal ileum were influenced by processing method used for preparation of ACP (P < 0.05). Amino acid pattern at the proximal duodenum was not affected by treatment. Methionine and lysine concentrations were lower in mixed bacteria isolated from the rumen of sheep fed APC prepared by anaerobic fermentation and spray dried when compared to other treatments. Apparent ruminal degradability of individual amino acid was influenced by method of preparation for APC (P < 0.05). Bacteria contributed 5574% of total amino acids flowing to the duodenum. Approximately 72% of the amino acids reaching the duodenum disappeared in the small intestine regardless of treatment. Amino acid pattern of residual proteins differed from respective dietary proteins. Results reveal that not all proteins entering the small intestine of ruminants are of equal quality.