Effects of Tenebrio molitor meal supplemented with Saccharomyces cerevisiae and/or Bacillus velezensis on production performance and egg quality in laying hens

This study investigated whether probiotic supplementation ( Bacillus velezensis and Saccharomyces cerevisiae ) can enhance the nutritional value of mealworm ( Tenebrio molitor ) and improve performance and eggshell quality in 68-week-old Lohmann Selected Leghorn-Lite hens. A total of 180 hens were randomly assigned to five dietary treatments in a completely randomized design with six replicates per treatment: (1) basal diet (control); (2) basal diet + 2% mealworm powder (MW); (3) MW + 500 mL S. cerevisiae suspension (1 × 10 8 CFU/mL; MW + SC); (4) MW + 500 mL B. velezensis suspension (1 × 10 9 CFU/mL; MW + BV); and (5) MW + a mixture of 250 mL B. velezensis and 250 mL S. cerevisiae suspensions at the same concentrations (MW + MIX). Egg production, egg mass, feed conversion ratio, and internal egg quality (yolk index, egg shape index, Haugh unit, albumen weight, and yolk weight) were not significantly affected (P > 0.05). Egg weight increased in MW and MW + BV groups, while MW + SC slightly reduced it (P = 0.04). Eggshell weight and thickness were highest in the control and MW + SC groups and lowest in MW + MIX (P = 0.002 and P = 0.01, respectively). Overall, these results indicate that inclusion of 2% MW powder in the diets of aged laying hens did not adversely affect performance. The effects of probiotic supplementation were strain-dependent, and combined probiotic treatments did not demonstrate synergistic benefits, highlighting the need for careful selection and formulation of probiotic strains.