## 3 Results and Discussion
### Fatty Acid Content  
The results of our study (Table 2) have shown that larvae in group 3L exhibited a significantly higher percentage of C16:0 (35.14 \(\pm\) 0.113%) compared to other larval groups, while C12:0 was notably abundant in larvae from group 3L (4.05 \(\pm\) 0.001%), showcasing the sensitivity of this SFA to specific dietary components. Larvae in group 1L displayed a distinct elevation in C16:1 (3.69 \(\pm\) 0.011%), underlining the influence of their unique dietary substrate on monounsaturated fatty acid content. C18:2 cis W-6 exhibited significant variations among larvae samples, with 1L and 4 CL larvae demonstrating higher percentages compared to other samples, illustrating the specific modulation of this PUFA by distinct substrates (\(p\) < 0.05). The essential omega-3 fatty acid in 2L, C20:3-w3 with 13.46 \(\pm\) 0.22%, exhibited notable differences (\(p\) < 0.001) among larvae groups, emphasizing the role of substrate composition in shaping the nutritional quality of larvae. Larvae from group 4 CL displayed a higher percentage of DHA (4.19 \(\pm\) 0.003%), also known as essential alpha-linolenic acid, suggesting a potential association between the choice of substrate and the synthesis or accumulation of this essential fatty acid. [PERSON] et al. from Cambridge University have analyzed the meat of chickens fed with a substrate containing the mealworm _T. molitor_. The results have demonstrated that breast meat showed higher percentages of oleic and \(\alpha\)-linolenic acids and lower atherogenicity and thrombogenicity indexes. Therefore, it can be assumed that changing the composition of FAs in feed can have a positive effect on animal health [54]. According to [PERSON] et al., higher circulating concentrations of pentadecanoic acid (C15:0) and heptadecanoic acid (C17:0) in humans are associated with a lower risk of cardiometabolic disease, lower mortality, and better physiological condition [55]. Our results have shown the fatty acid profile of substrate and larvae fed with experimental diets. The highest amounts of C17:0 fatty acid were determined in the sample 2L (9.60 \(\pm\) 0.009%), while they were not detected in the substrate at all, and this is a significantly lower amount compared to the larvae (0 < 0.01). [PERSON] et al. tested different treatments for mealworms in their study, focusing on fatty acid composition and other parameters [42]. The results have shown that the lowest amount detected in the sample (C18:1) was observed when cooked at 70 \({}^{\circ}\)C for 30 min (25.11%), while the highest amount (40.68%) was found in uncooked mealworms. In our study (Table 2), the lyophilization method was used, and for comparison, the sample 3L contained the least amount of C18:1 acid (33.303 \(\pm\) 0.067%), while the highest amount,according to [PERSON] et al., was 39.24 \(\pm\) 0.002%. Hence, the upper limit of detection aligned closely with our findings [42]. To summarize, larvae in 3L exhibited a beneficial fatty acid composition, especially in oleic acid. The unique fatty acid profiles identified across different larval groups emphasize the significance of customizing larval diets to achieve specific fatty acid compositions. These discoveries provide valuable insights for enhancing insect-rearing methodologies with the goal of producing larvae with tailored nutritional profiles suitable for diverse applications, including animal feed or human consumption. These data suggest that the nutritional composition of mealworms, specifically in terms of FAs, is distinct from the substrate they are cultivated on (Table 3). Particularly, larval samples demonstrated significantly higher levels of C12:0, C16:1, C18:1 cis, C18:2 trans, and C20:1, compared to substrate (\(p\) < 0.001). The observed variations may have implications for the potential use of mealworms as a sustainable and nutrient-rich food source. Further research and exploration into the factors influencing these fatty acid profiles could contribute to the optimization of mealworm cultivation for specific nutritional purposes.