Effect of amino acid injection in broiler breeder eggs on embryonic growthand hatchability of chicks

Two experiments were conducted to evaluate the effect of amino acid (AA) in jections in ovo in Cobb broiler breeder eggs on hatchability and subsequent chick BW. Ln Experiment 1, moisture, crude fat (CF), and CP were analyzed over time during incubation (Day 0, 7, 14, and 19 of incubation). Moisture, CP, and CF of the embryo increased, and moisture, CP, and CF of eggs decre ased, as incubation time increased (P < 0.05). Combined egg and embryo AA c ontents, except Gly and Pro, decreased (P < 0.05) as incubation time increa sed. However, the pattern of AA in the egg did not change as the embryo dev eloped. In Experiment 2, AA were injected into the yolk or air cell at Day 0 and 7 of incubation. Hatchability was reduced (P < 0.05) when AA were inj ected at Day 0 of incubation. However, when the AA solution was injected in to the yolk sac at Day 7 of incubation, hatchability was not affected, and BW of chicks increased relative to egg weight prior to incubation. These re sults suggest that in ovo administration of AA may be an effective method o f increasing chick BW at hatch.