Effects of the commercial in ovo injection of 25-hydroxycholecalciferol on the hatchability and hatching chick quality of broilers.

The effects of the in ovo injection of commercial diluent containing various levels of 25-hydroxycholecalciferol [25(OH)D3] on hatchability and hatching chick quality variables in Ross × Ross 708 broilers were examined in 2 trials. All treatment groups, each containing 21 and 40 eggs in trials 1 and 2, respectively, were randomly represented on each of 10 replicate tray levels of a single-stage incubator. On 18 d of incubation (doi), eggs were subjected to 1 of 6 treatments using a commercial multi-egg injector. Treatments included noninjected and diluent-injected controls, along with those that received diluent containing 0.15, 0.30, 0.60, or 1.20 µg of 25(OH)D3 in trial 1 and 0.20, 0.60, 1.80, or 5.4 µg of 25(OH)D3 in trial 2. Hatchability of injected eggs (HI) was recorded on 20.5, 21.0, and 21.5 doi, and embryonic mortalities through 21.5 doi were determined. On 21.0 doi in each trial, the BW, body length, and weights and moisture concentrations of the livers and yolk sacs of male and female chicks in each replicate group were determined. In a preliminary trial, the in ovo injection of 0.60 µg of 25(OH)D3 on 18 doi significantly elevated its serum level concentrations in embryos on 19.25 doi. In both trials, the HI of noninjected controls through 21.0 doi was higher than that of diluent-injected controls. In trial 1, the HI of eggs on 21.0 doi after being injected with 0.30, 0.60, or 1.20 µg of 25(OH)D3 was higher compared with that of diluent-injected controls, and in trial 2, the HI of eggs on 21.0 and 21.5 doi after being injected with 0.60 µg of 25(OH)D3 was higher compared with that of diluent-injected controls. In conclusion, the in ovo injection of 0.60 µg of 25(OH)D3 may be used to alleviate depressions in HI in Ross × Ross 708 broiler hatching eggs that can occur in response to the in ovo injection of commercial diluent.