Effect of Supplementing a Mixture of Digestive Enzymes and a Probiotic to a Low-Energy and Low-Protein Diet on Egg Quality Traits and the Chemical and Biochemical Characteristics of Egg Yolk in Laying Hens

The present study aimed to investigate the effect of supplementing a mixture of multi-enzymes and a probiotic to a low-energy and low-protein diet of laying hens (Lohmann Brown) on selected productive performance parameters and egg quality traits. The experiment was conducted over three consecutive periods covering the age range from 46 to 54 weeks. A total of 80 laying hens were randomly allocated to four experimental treatments T1, control diet with standard energy and protein levels. T2, low-energy and low-protein diet without additives. T3, low-energy and low-protein diet supplemented with enzymes and T4, low-energy and low-protein diet supplemented with a probiotic. results indicated that T4 showed a significant improvement (P ≤ 0.05) in internal egg quality traits, particularly albumen index, Haugh unit , and yolk index, compared with T2 and the control treatment. Furthermore, the findings demonstrated that dietary supplementation played a significant role in maintaining productive performance stability and improving feed conversion efficiency despite the reduced nutrient density of the diet. In addition, a noticeable improvement was observed in oxidative indicators along with a reduction in yolk cholesterol levels. These results confirm the efficacy of this biological mixture as a strategic nutritional alternative for reducing feed costs without adversely affecting the qualitative and physiological standards of the final product.