Standardization of injection site, needle length, embryonic age and concentration of amino acids for in ovo injection in broiler breeder eggs

In the first experiment, the injection site (broad and narrow) and needle length (11 and 24 mm) for in ovo injection was evaluated on 7th and 14th day of embryonic age. Where 160 standard size fertile eggs were distributed in 8 groups, 4 groups of eggs were injected with AA solution (20 naturally occurring amino acids) to see the effect on hatchability and chick weight at hatch and other 4 groups were injected with the Indian ink to assess the deposition of AA in the developing embryo. In the second experiment the embryonic age for in ovo injection (0, 7 and 14th d) and concentration of aminoacids (0, 0.25 and 0.50% of egg aminoacids) were studied in a 3x3 factorial design. Wheninjected with 24 mrn needle at both end, either on 7th or 14th day of incubation in majority cases the ink was deposited in the yolk sac of the embryo. Where as with 11 mm needle, when injected at broad end, either on 7th or 14th day of incubation the ink was deposited partly in the air cell and chorio-allantoic cavity, whereas, at narrow end ink was deposited in the albumen of the egg with minimum contact to embryo. Hatchability was poor when AA was injected at broad end with 11 mrn needle and at narrow end with 24 mm needle (8.0, 6.25 vs 90.0% in control, respectively). Irrespective of concentration of AA, the in ovo injection on 0th (29.0%) and 7th (37.3%) day had lower hatchability as compared to that on 14th day of embryonic age (81.5%) and control (78.0%). When chick to egg weight ratio, was compared there was significant difference between concentrations of AA (P<0.011) and days of injection (P<0.043). AA injected on 14th day had 2.1%higher chick weight as compared to un-injected control.