Study of Probiotic-Enriched Diet Effects on Yellow Mealworm Larvae Production at Laboratory and Pilot Scales

Global food security is an increasing challenge due to population growth and the limited availability of natural resources, driving the search for sustainable protein sources. In this context, edible insects such as yellow mealworms (Tenebrio molitor) have emerged as a promising alternative, while probiotics have been widely applied in animal production to enhance growth performance and nutritional quality. This study aimed to evaluate the effects of probiotic supplementation on the growth performance, biomass yield, and nutritional composition of yellow mealworm larvae at laboratory and pilot scales. Three probiotic strains—Bacillus velezensis, Bacillus coagulans, and Pediococcus pentosaceus—were tested at four different dosage levels, using wheat bran and brewer’s spent grain as feed substrates. Larval growth was monitored weekly, and total harvested biomass, proximate composition (dry matter, protein, fat, and ash), amino acid profile, and mineral composition were determined using standardized analytical methods. At the laboratory scale, probiotic supplementation did not result in significant differences in mean larval weight or total biomass (p > 0.05). In contrast, at the pilot scale, significant improvements in larval growth and biomass were observed for specific probiotic treatments, with mean larval weights reaching approximately 140–150 mg and total harvest biomass increases of up to ~15% compared to the control (p < 0.05). Growth curves at both scales followed a sigmoidal pattern with a high correlation between laboratory and pilot experiments (R2 = 0.98). Probiotic supplementation did not significantly affect crude protein content, but alterations in fat content, specific amino acid concentrations, and mineral composition were observed at the pilot scale, depending on strain and dosage. Overall, the results demonstrate that probiotic supplementation can enhance yellow mealworm production under pilot-scale conditions, while laboratory-scale trials may not fully capture these effects. These findings highlight the importance of scale when evaluating probiotic strategies and support the potential application of Bacilli-based probiotics to improve the efficiency and nutritional quality of industrial insect production systems.