Myo-inositol metabolism in two high-performance laying hen strains at different production periods.

This study aimed to investigate myo-inositol (MI) metabolism in two high-performance laying hen strains and to assess the effects of MI or mineral phosphorus supplementation at different production periods. Diets were corn-soybean meal-based and supplemented with MI (0, 1, 2, or 3 g/kg feed) in experiment 1 or with mineral phosphorus (0 or 1 g/kg feed) in experiment 2. Following a 4-week feeding period in metabolic units, ten hens per strain (Lohmann Brown-Classic and Lohmann LSL-Classic) and diet were euthanized at 30 weeks of age (experiment 1) and at 19 and 24 weeks of age (experiment 2). Plasma, liver, muscle, and kidney samples were collected from each hen. Tissue MI concentrations were measured using a commercial spectrophotometric kit, and concentrations of insulin and key enzymes (inositol monophosphatase and MI oxygenase) were quantified using ELISA kits. As diets did not affect tissue MI or enzyme concentrations, data from the two experiments were combined for further analysis. Changes across periods suggest that insulin influenced kidney MI oxygenase concentration and consequently played an essential role in the metabolic adaptation to egg laying. The results also indicated that higher liver and muscle MI concentrations in Lohmann Brown-Classic hens are potentially associated with metabolic adaptation to the onset of egg laying. Further research is needed to elucidate the role and regulation of MI in laying hens, particularly at the onset of egg laying.