Evaluation of tryptophan biomass as an alternative to conventional crystalline tryptophan in broiler diets

Abstract

The current experiment was conducted to evaluate tryptophan (Trp) biomass as an alternative to conventional crystalline Trp in broiler diets. In a growth trial, a total of 288 eight-d-old chicks were randomly allotted to 1 of 3 treatments with 8 replicates. A negative control (NC) diet was formulated to contain 40% less amounts of digestible Trp than its requirement. A positive control (PC) diet was formulated to meet digestible Trp requirement by supplementing with crystalline Trp. An additional diet was prepared by supplementing Trp biomass to have equal amounts of digestible Trp in the PC diet. In a metabolism trial, a total of 54 forty two-d-old chickens were allotted 1 of 3 dietary treatments used in the growth trial with 9 replicates to evaluate the effect of dietary Trp biomass on gross energy (GE) and nitrogen (N) utilization in broiler diets. Results indicated that PC and Trp biomass treatments had greater ( P < 0.05) body weight gain (BWG) and feed intake (FI) than NC treatment. The Trp biomass treatment showed no differences in BW, BWG, and FI compared with PC treatment. The PC treatment had less ( P < 0.05) blood heterophil to lymphocyte ratio than NC treatment. The PC and Trp biomass treatments had greater ( P < 0.05) villus height to crypt depth ratio than NC treatment. Inclusion of Trp biomass did not affect GE and N utilization in broiler diets. In conclusion, Trp biomass can be used as a potential alternative to conventional crystalline Trp in broiler diets.