Impact of Artificial Feed-Infused Nickel Nanoparticles Functionalized with Urease (Ni-Urease) on the Growth and Properties of Silkworms (Bombyx mori)

Urease stability has been a challenge with silkworms reared on artificial feed, which affects the growth and development of silkworms and silk yield. Providing a stable resource to solve this problem and advance the sericulture industry is crucial. In this study, nickel (Ni), a key activator of the urease enzyme, is used to immobilize urease using nickel nanoparticles (NiNPs) as an artificial feed additive for silkworm larvae from the fifth instar to overcome the deficiency of urease in silkworm artificial feed. Nanoparticles were used to increase the bioavailability and efficacy of nutrients, aiding in the absorption and physiological use in silkworms for better silk production. The growth of silkworm larvae was characterized according to their physical appearance and tissue morphology. The distribution of Ni in tissues was determined by inductively coupled plasma mass spectrometry (ICP-MS). The properties of silk were analyzed and characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetry (TGA), and quasi-static stretching (QSS). The results showed that adding Ni-Urease in artificial feed could promote the growth of silkworm larvae by 0.08 g/day and 0.1 cm/day in weight and length, respectively, compared with the control group. The silk yield increased by 43.30%, with an enhanced crystallinity (6.12%) and tensile strength (74.26 MPa). The results also offer a cost-effective solution with a significant improvement in silk yield and higher potential revenue from increased production.