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 × 10⁸ CFU/mL; MW + SC); (4) MW + 500 mL B. velezensis suspension (1 × 10⁹ 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.