In ovo supplementation of caffeine to embryos from young broiler breeders

ABSTRACT This study evaluated the effects of in ovo caffeine supplementation on hatchability, embryonic mortality, thermodynamic parameters, plasma biochemical profile, and gastrointestinal morphology in broiler embryos. A total of 200 fertilized eggs were distributed into five groups: control (untreated), saline solution (0.5%), and caffeine solutions at 0.5%, 1.0%, and 1.5%. The results showed a significant decrease in hatchability and an increase in embryonic mortality with higher caffeine concentrations, suggesting osmotic and metabolic imbalances. Plasma biochemical analysis revealed that moderate caffeine levels (0.5%) positively influenced protein metabolism, while higher doses disrupted lipid and protein homeostasis. Thermodynamic parameters indicated a quadratic response, with intermediate caffeine levels favoring thermal regulation. Gastrointestinal morphology showed enhanced liver and yolk sac growth at moderate caffeine levels, but excessive doses led to intestinal structural alterations. These findings suggest that in ovo caffeine supplementation at 0.5% may offer metabolic benefits without compromising embryonic development. However, higher concentrations have adverse effects, highlighting the need for dose optimization in poultry nutrition.