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In modern broilers, the period of embryonic development constitutes a greater proportion of a broiler's productive life. Hence, optimum embryonic development can exert a significant influence not only on chick hatchability and hatchling quality but also on overall broiler growth and performance. Further healthy and active hatchlings are correlated with improved post-hatch performance. In this regard, probiotics are good candidates to mediate early-life programming. Therefore, we evaluated the effect of in ovo probiotic spray application on broiler hatchability and hatchling quality. The experiment was set out as a completely randomized study with two independent trials. In each trial, 540 eggs (Ross 308) were either sprayed with phosphate buffered saline (PBS; control) or probiotics ∼9 log CFU/egg of Lactobacillus rhamnosus NRRL B-442(LR) or Lactobacillus paracasei DUP 13076 (LP) during incubation. On day 18, eggs were transferred to the hatcher and set up for hatching. Starting on day 19, eggs were observed for hatching to determine the spread of hatch and hatchability. Hatched chicks were then assessed for quality using the Tona and Pasgar score and morphometric measurements including hatchling weight, yolk-free-body-mass and hatchling length were measured. Further, chicks were reared in floor pens for three weeks to assess post-hatch growth. Overall, in ovo probiotic supplementation improved hatchability and hatchling quality. Specifically, the spray application of LP improved hatchability by ∼ 5% without affecting the spread of hatch. Further, both LR and LP significantly improved Pasgar and Tona score, indicating an improvement in hatchling quality. Also, LP and LR significantly improved hatchling weight, yolk-free-body-mass, and post-hatch growth in chicks. LR significantly improved hatchling weight and hatchling length (P < 0.05). Moreover, this increase in post-hatch growth was positively correlated with hatchling weight in the probiotic groups. Overall, our study demonstrates that in ovo probiotic application exerts a positive effect on hatchability, hatchling quality and subsequent post-hatch growth.
Gao et al. (Thu,) studied this question.