Soybean Flour Fortified with Gryllus assimilis Powder to Increase Iron Bioavailability Improves Gut Health and Oxidative Balance In Vivo

Abstract

Background: Insects like Gryllus assimilis have an excellent nutritional profile, including iron. However, the bioavailability of this iron and its effects on intestinal health and oxidative balance remain unclear. To enhance acceptance, insects can be used in powder form and combined with common flours.

Objective: This study evaluates the effects of Gryllus assimilis powder, alone or with soy flour, on iron bioavailability, intestinal health, and oxidative balance in rodents.

Methods: Using the hemoglobin depletion/repletion method, 32 male Wistar rats were divided into four groups: A (standard diet + ferrous sulfate), B (diet + Gryllus assimilis + soy flour), C (diet + Gryllus assimilis), and D (diet + soy flour). Hemoglobin levels, regeneration efficiency, biological value, serum markers, intestinal health, and oxidative balance were assessed.

Results: Food intake, weight gain, and bioavailability measures showed no differences. However, the Gryllus + soy group showed higher weekly and final hemoglobin levels than Gryllus alone. This combination also improved acetic acid levels, fecal moisture, and oxidative balance, increasing superoxide dismutase activity while reducing peroxidation products compared to Gryllus alone.

Conclusion: These findings highlight the potential benefits of combining Gryllus assimilis with soy flour for iron bioavailability and overall health.

Keywords: biological availability; edible insects; entomophagy; minerals.

Figure 1

Histological section of the intestinal epithelium (duodenum) for the analysis of the mucosa and submucosa. Cross section of the duodenum of Wistar rats subjected to an analysis of iron bioavailability using the depletion/repletion method. (A) SF: Ferrous Sulfate group; (B) GP + FS: Gryllus assimilis powder associated with soy flour (15:85) group; (C) GP: Gryllus assimilis Powder group; (D) FS: Soy Flour group. The black lines indicate how the measurements of the mucosal thickness were made. The red lines indicate how the measurements of the submucosal thickness were made.

Figure 2

Histological section of the intestinal epithelium (duodenum) for the analysis of the goblet cells. Cross section of the duodenum of Wistar rats subjected to an analysis of iron bioavailability using the depletion/repletion method. (A) SF: Ferrous Sulfate group; (B) GP + FS: Gryllus assimilis powder associated with soy flour (15:85) group; (C) GP: Gryllus assimilis Powder group; (D) FS: Soy Flour group. The yellow lines indicate how the measurements of the diameters of the goblet cells were made.

Figure 3

Effect of consumption of Gryllus assimilis powder alone or associated with soy flour on in vivo oxidative balance. SF: Ferrous Sulfate; GP + FS: Gryllus assimilis powder associated with soy flour (15:85); GP: Gryllus assimilis Powder; FS: Soy Flour. (A) Catalase, (B) superoxide dismutase, (C) glutathione S-transferase, (D) malondialdehyde, (E) nitric oxide, and (F) protein carbonylate. Different lowercase letters (a–c) indicate intragroup differences, according to ANOVA tests followed by a Tukey’s test at a 5% probability. Data are expressed as the mean ± standard deviation.