Effect of spirulina fortification on the digestive protease, carbohydrases and cocoons economic traits of mulberry silkworm Bombyx mori

Abstract

Bombyx mori, the silkworm, is a voracious feeder that relies on digestive enzymes for mulberry digestion and its conversion in to silk. In the current study, fifth-instar larvae were given 2% spirulina supplementation with commercially graded spirulina samples, and a few digestive enzymes and cocoon traits were examined. The treatment groups of silkworms T1-control, T2-supplemented with spirulina powder graded for animal dietary consumption, T3- graded for human dietary consumption and T4-spirulina graded for medicinal applications. Spirulina supplementation was tested in silkworms for digestive protease, carbohydrases and cocoon traits. The results shows that the total protein content percentage difference (PD) in the gut wall was increased by 2.79% in T3, 1.96% in T4, and 0.78% in T2 compared to T1 (control). A similar trend was noticed in the gut content, with the PD of 15.81% in T3, 7.51% in T4, and 3.95% in T2. In total carbohydrate content, observed PD of 16.35% in T2, 11.27% in T3, and 9.38% in T4, while the gut content was 13% both in T2 and T3, and 1.22% in T4. The protease activity PD of gut wall tissue has 21.99% in T3, 5.13% in T2, and 4.30% in T4; similarly, the gut content has a PD of 112.38% in T3, 106.12% in T4, and 86.41% in T2. The amylase activity have shown highest PD in T4 (33.43%), T3 (23.37%), and moderate in T2 (19.23%) in the gut wall, and 93.10% in T3, 66.44% in T2, and 14.92% in T4 of gut content. Enzymes such as sucrase, cellulase, and pectinase have also improved with spirulina fortification. The sucrase activity in the gut wall and gut content were, respectively, 7.99% and 80.73% in T3 treatment. Noteworthy, the T2 showed 37.69% in the gut wall and 24.54% in the gut content for the cellulase activity. Unlike cellulase, pectinase activity has been observed with a PD of 93.15% in the gut wall and 64.63% in gut content. The study further confirms that the additional fortification of spirulina will have a beneficial effect on the digestive cells of the silkworm, Bombyx mori, resulting in the highest rate of enzyme activity and in turn, increasing survivability.