Black Seed and L-carnitine Mitigate Heat Stress in Japanese Quails Egg Quality Organ Morphology

Background: Heat stress negatively impacts egg production and health in quails, prompting research on dietary supplements, like black seed and L-carnitine for their potential to alleviate these effects and improve performance. Objectives: This study evaluated the effects of black seed, L-carnitine, and their combination on egg production and intestinal and magnum morphology in laying Japanese quails under normal and heat stress conditions, with an additional assessment of vitamin E supplementation. Methods: Five-hundred laying Japanese quails were divided into two temperature groups (normal and heat stress) and five dietary treatments (control, black seed, L-carnitine, black seed + L-carnitine, and vitamin E) in a ۲×۵ factorial design. The experiment consisted of acclimation (two weeks), heat exposure (five weeks), and recovery (three weeks). Egg production and intestinal and magnum morphology were measured throughout the entire period. Results: During heat stress, control and black seed diets resulted in higher Haugh unit values, while the black seed + L-carnitine diet increased yolk percentage. Vitamin E improved eggshell strength under normal conditions, and after recovery, both vitamin E and black seed + L-carnitine diets produced stronger eggshells (P<۰.۰۵). Black seed + L-carnitine reduced the the ratio of villous length to crypt depthcompared to the controls. Vitamin E under heat stress and black seed + L-carnitine under normal conditions increased magnum fold height, while the control diet under heat stress had the lowest fold thickness. Vitamin E enhanced epithelial height under normal temperatures and reduced magnum gland diameter (P<۰.۰۵). Conclusion: Black seed and vitamin E improved egg quality (Haugh unit, shell strength), while black seed + L-carnitine had mixed effects on morphology depending on temperature. Dietary strategies can optimize the performance of laying Japanese quails under different conditions.

کلیدواژه ها:

black seed ، egg quality ، heat stress ، l-carnitine ، Laying Japanese quail