Metabolism and Nutrition: Amino Acids

Feed accounts for 60 to 70% of broiler production costs . Thus, improvement in feed efficiency is needed. Ileal digestibility (ID) and total-tract amino acid (AA) utilization are the parameter used to evaluate feed ingredients . However, ID of AA can be affected, for example, by gut inflammation as a result of a coccidial vaccine challenge. Adedokun et al. (2014) showed significantly high ileal endogenous AA losses and a significant decrease in apparent ID as a result of gut inflammation. The hypothesis that surplus AA above recommendation will ameliorate the effect of inflammation from mild coccidial vaccine challenge was tested in 192 male Ross 708 broilers randomly allocated to 3 treatments (8 replicates each of 8 birds): PC (unchallenged) fed diet without AA uplift, NC (challenged with 10× Coccivac B) fed diet without AA uplift, and NC (challenged with 10x Coccivac B) fed diet with AA uplift . Diets with AA uplift contained an increased amount of digestible AA . After individual weighing and randomization (CRD), half of the birds were gavaged with 0 .6 mL of distilled water containing (10× Coccivac B) vaccine on d 15 . All birds were sampled on d 21 after 7 d being on the experimental diets . Control diets were formulated according to AminoChick (2010), test diet was formulated by using coefficients for standardized AA ID according to Adedokun et al . (2014) . Diets were iso-caloric and fed ad libitum . Cocci challenge resulted in a decrease (P < 0 .05) in BWG (358, 287, 307g for PC, NC, +AA) . However, the AA uplift improved feed efficiency to that of the PC birds (0.737, 0.671, 0.715 g/g for PC, NC, +AA) . AA uplift resulted in numerical improvement for nitrogen ID in challenged birds (76 .8, 75 .8, 77 .1% for PC, NC, AA lift) . Majority of growth depression resulted from a decrease in digestible energy (about 3 .5%) . In conclusion, an uplift in AA ID improves growth performance of cocci challenged growing broilers although the digestibility of energy still accounts for the biggest part in growth depression .