The nutrient composition of yellow mealworm (YM) Tenebrio molitor varies based on the stages of the life cycle, the rearing conditions, and the feeding substrate. This study monitored the growth of yellow mealworm larvae at 8, 10, and 12 weeks of age, separating samples into large-sized and small-sized insects. During the experiment, we measured the nutrient composition: dry matter (DM), crude protein (CP), crude fat (CF), crude fibre, chitin, crude ash, and nitrogen free extract (NFE) of YM at different age groups and sizes. We measured the nutrient composition of the pre-moult, moult, cuticle, and pupae as well. The results show that there is no significant difference between the compositions of the different age groups, but larger-sized individuals had a higher DM and crude fibre and lower chitin and NFE than the smaller sizes. The pre-moult and moult stages showed no significant difference in nutrient composition. Although the cuticle had a high DM (97.5%), that did not cause any significant difference between the DM of the moult and pre-moult, because it is only a negligible part of the total wet weight. With the increased DM, the crude protein content and the chitin content, fibre, ash content, and NFE increased, while the fat content decreased. The DM, CF, and chitin contents of pupae are significantly lower than those of the pre-moult and moult stages. Our results show that it is the size and not the age that has a positive effect on the nutrient composition of YM.

This research explores the potential of using common duckweed (Spyrodela polyrhiza) as a feeding substrate and supplement for yellow mealworm production. Duckweed is known for its high content of protein (20–35%) and essential amino acids. This study aims to assess the effect of the combination of semolina and duckweed as a feeding substrate for yellow mealworm larvae (Tenebrio molitor). The experiment involved different combinations of semolina and duckweed in varying proportions. The treatments included 100% semolina (S), 75% semolina + 25% duckweed (S75D25), 50% semolina + 50% duckweed (S50D50), 25% semolina + 75% duckweed (S25D75), and 100% duckweed (D). Over a six-week period, the production parameters, nutrient composition, amino acid composition, and fatty acid composition of the yellow mealworms were measured and analyzed. The results demonstrate that S75D25 and S50D50 feed combinations were recommended due to their positive effects on production parameters and nutrient composition. Although the D substrate exhibited the highest crude protein content, yellow mealworm larvae did not grow on this substrate. The inclusion of duckweed in the feed had no significant effect on the fatty acid composition of the mealworms, while substrates S25D75 and D induced an improved amino acid composition. In conclusion, incorporating duckweed into the feeding substrate can enhance the production parameters and nutrient composition of yellow mealworms.

The consumption of insect protein, as well as its use in animal feeding, has become a trend. This trend is particularly receiving a lot of attention in animal nutrition because the current protein source of the highest quality in animal feeding which is fishmeal is unsustainable, expensive and its demand is higher than supply. Insect protein can be of great potential in combating world hunger as the world population continues to increase. The potential of insect protein is wide-ranging, it could improve the economics of feed production, lead to cleaner production due to its low environmental footprint. This review focuses on the need, (nutritional and environmental) advantages of insect protein in feed production, as well as previous research findings. The unanimous conclusion of the reviewed papers is that insect protein has a great potential in feed production in terms of nutritional value, environmental implication, sustainability as well as economic implication. However, there is a need for the intensification of research on this alternative protein source in Europe, especially in aquaculture due to the approval of 7 insect species in aquafeeds by the European Union. Another reason for the intensification is that there is still much to be done as a result of past research which shows that growth effects vary based on species and inclusion level.

Click on the article title to read more.