Use of Tenebrio molitor meal in the diet of shrimp (Penaeus vannamei) as a chemopreventive alternative against microplastic exposure
Author: Diogo Pereira Chamorro (Currículo Lattes)
Advisor: Dr. Juliane Ventura Lima
Abstract
In the environment, plastic materials may undergo environmental degradation, leading to the formation of particles smaller than 5 mm, known as microplastics (MP). Due to their small size, marine organisms ingest them accidentally or as part of their diet. These particles can accumulate in tissues, inducing various effects including oxidative stress. To minimize the redox imbalance induced by MP, the addition of antioxidants to the diet can be a chemoprotective strategy. One alternative is the use of insect meal, such as Tenebrio molitor meal, which may enhance antioxidant capacity at certain concentrations; however, its effect in the presence of MP has not been reported. Given this, the objective of this study was to evaluate the use of T. molitor meal in the diet of shrimp (Penaeus vannamei) as a chemoprotective alternative against MP exposure. Six diets were formulated: fishmeal (CTL), replacement with 15% and 30% T. molitor meal (CTL15 and CTL30, respectively), fishmeal plus 40 µg of polystyrene MP (spherical, 1.1 µm), and replacement with 15% and 30% T. molitor meal plus 40 µg of MP (MP15 and MP30, respectively). The animals were fed the diets for 21 days. At the end of the experiment, shrimp were euthanized for collection of gills, hepatopancreas, and muscle for further analyses. Results showed that CTL30 promoted better growth. In the hepatopancreas, CAT activity was higher in animals exposed to MP at both inclusion levels of T. molitor (15% and 30%) compared to the respective control groups. In the same tissue, GSH levels increased in the control group receiving 15% inclusion, and this increase was also observed in the MP15 group. Considering SOD activity, there was a decrease in CTL30 in gills compared to CTL, while in the hepatopancreas, the MP30 group showed reduced enzyme activity compared to CTL30. In the hepatopancreas, GPx activity in the CTL30 group was higher than in the CTL0 group. In gills, the presence of T. molitor meal reduced lipid peroxidation levels in CTL15 and CTL30 compared to CTL0, while the MP30 group showed reduced lipid damage compared to its control group (CTL30). In the hepatopancreas, the CTL15 group showed higher lipid damage levels compared to CTL0 and CTL30, while the MP15 group showed a reduction in lipid damage compared to the corresponding CTL15 group. In all three analyzed tissues, the presence of MP was confirmed. Based on the results obtained, it can be observed that partial replacement of fishmeal with T. molitor meal improves antioxidant capacity in control groups, particularly considering GSH levels. The use of T. molitor demonstrated potential for activating the antioxidant system, representing a promising chemopreventive strategy in aquaculture.