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

Two experiments were conducted to evaluate the effect of amino acid (AA) injections 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 decreased, as incubation time increased (P < 0.05). Combined egg and embryo AA contents, except Gly and Pro, decreased (P < 0.05) as incubation time increased. However, the pattern of AA in the egg did not change as the embryo developed. 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 injected at Day 0 of incubation. However, when the AA solution was injected into 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 results suggest that in ovo administration of AA may be an effective method of increasing chick BW at hatch.