Impact of in ovo myo-inositol administration on immune modulation in broiler chickens.

Myo-inositol (MI) plays an important role in intracellular signaling, cell proliferation, and cell growth, and has been associated with positive effects on the immune system and health in fish. However, its potential immunological effects in poultry have not been investigated yet. This study aimed to evaluate the effects of in ovo MI administration on immune parameters in broiler chickens after hatching. A total of 480 fertilized Ross 308 eggs were randomly assigned as hatched to four groups and injected on embryonic day 17 with either 12 µmol/mL MI (MI-12), 24 µmol/mL MI (MI-24), 0.9% saline (positive control, PC), or left untreated (negative control, NC). After hatching, broilers were housed in floor pens. On day 35, eight birds per treatment group were sampled for analysis of leukocyte subsets and antibody concentrations in blood. Overall, in ovo MI administration had only slight effects on the immune parameters. Birds in the MI-24 group had lower plasma IgM concentrations and showed a tendency toward lower CD4+ cell numbers, while no effects were observed on the numbers of other investigated immune cell populations or antibody classes. The current findings should be considered hypothesis-generating given an unbalanced sex distribution across groups. Together, the results suggest that in ovo MI administration at the end of embryogenesis may influence immune cell function rather than cell development. Moreover, neither piercing the eggshell nor injecting fluid affected the immune parameters analyzed, indicating that this technique does not compromise the immune system at this stage of embryonic development.