Evaluation of the possibilities to use gastronomic by-products as feed for the yellow mealworm (Tenerbio molitor)

The gastronomic industry generates by-products, which could be used as insect feed. The objective of the experiment was to determine the potential of utilising post-gastronomic plant and animal products as a feed source for mealworm larvae. The insects were fed diets comprising of varying proportions of plant or animal fractions. The control group (Ctrl) received oatmeal with apples, while the experimental groups received oatmeal mixed with different proportions of the plant and meat fractions of restaurant leftovers. The plant fraction was incorporated into feed at 25, 50, and 75% (groups R25, R50 and R75), while the meat fraction was mixed at 25 and 50% (groups M25 and M50). The experiment lasted 48 days. The highest dry matter (DM) intake was observed in the M25 and R75 groups. Larvae in the experimental groups exhibited higher final body mass and total mass gain compared to the Ctrl group (p < 0.01). The survivability of larvae in the R50 and M25 groups was significantly higher than the Ctrl group (p < 0.01), while the lowest survivability was observed in the R25 group. The lowest feed conversion ratio (FCR) for dry matter was observed in the R50 and M50 groups, while the highest FCR was recorded in the M25 and Ctrl groups. The highest dry matter levels, crude protein, and crude fat were found in the M25 and groups (p < 0.01). Groups R25 and Ctrl exhibited the highest content of crude ash (p < 0.05). This suggests that mealworm larvae could be one of the potential solutions for the disposal of gastronomic by-products.