Toxicity and modulation of silver nanoparticles synthesized using abalone viscera hydrolysates on bacterial community in aquatic environment

Abstract

Polysaccharide decorated silver nanoparticles (AgNPs) are a new type of antibacterial agent in aquaculture, but their effects on the bacterial community structure in aquaculture water are still unknown. In this study, the primary hydrolysate from abalone (Haliotis discus hannai) viscera (AVH) was used to biosynthesize AVH-AgNPs by in situ reduction, and the crystallinity nature, size, morphology, and chemical composition were analyzed by high-resolution characterization techniques such as Ultraviolet–visible spectroscopy (UV–vis), X-rays diffraction (XRD), Transmission Electron Microscope (TEM), Dynamic light scattering (DLS), Zeta potential, inductively coupled plasma-optical emission spectrometry (ICP-OES) and Turbiscan stability index (TSI) values. Furthermore, the acute toxicity of AVH-AgNPs to zebrafish (Danio rerio) and their effects on bacterial community structure in fish culture water at low concentrations were studied. The results showed that the spherical AVH-AgNPs with an average diameter of 54.57 ± 12.96 nm had good stability, low toxicity, and good in vitro antibacterial activity. Within the experimental concentration range, all AVH-AgNPs treatments had decreased the bacterial diversity in zebrafish culture water to varying degrees. The bacteria with significantly decreased abundances were pathogenic or potential pathogenic, such as Aeromonas veronii, Flavobacterium columnare, and genera Flectobacillus and Bosea. The abundance of Haliscomenobacter sp. JS224, which might cause sludge swelling, also decreased significantly. On the other hand, the relative abundance of some bacterial taxa could remove xenobiotics (e.g., Runella defluvii and Phenylobacterium), control water eutrophication (Sediminibacterium), and reduce toxic algae proliferation (Candidatus Intestinusbacter nucleariae and Candidatus Finniella), increased significantly. Thus, the application of AVH-AgNPs in aquaculture water at low concentrations is relatively safe and has positive significance for improving the aquaculture environment. Also, AVH-AgNPs have good prospects in aquaculture.

Aaqueous exposure to silver nanoparticles synthesized by abalone viscera hydrolysates promotes the growth, immunity and gut health of zebrafish (Danio rerio)

“…The copper (Cu) element was mainly from the copper mesh used for the TEM test, and C and O elements were important constituents in the AVH ( Figure 1C ). Other characterization (UV–Vis, XRD, zeta potential, silver content and stability) has also been performed ( Zhang et al, 2022 ).…”

“…Fresh abalone viscera were purchased from Xiamen Dao Zhiyuan Biotechnology Co., Ltd., (Fujian, China), and the abalone viscera hydrolysates (AVH) were obtained according to the previously reported method ( Wang et al, 2015 ). The procedure for the preparation of AVH-AgNPs was also described in a previous work ( Zhang et al, 2022 ). Briefly, 125 ml each of 1.3 mM AgNO3 and 0.7 mg/ml AVH was dissolved in 375 ml of deionized water, and the pH of the mixture was adjusted to 7.0.…”

“…The other 3 groups were added with AVH-AgNPs at doses of 6 (group C1), 9 (group C2), and 18 μg/l (group C3). All concentrations of AVH-AgNPs were selected based on the acute toxicity test ( Zhang et al, 2022 ). During the 30-day experimental period, the fish were fed to satiation three times a day.…”

“…Other characterization (UV-Vis, XRD, zeta potential, silver content and stability) has also been performed (Zhang et al, 2022).…”

“…At present, the effects of AgNPs dispersed in aquaculture water on fish gut microbiota have not been reported before, while a comprehensive evaluation of the effect of AgNPs on cultured aquatic animals is a prerequisite for its application in aquaculture. In our previous study, the AVH-AgNPs with high dispersion stability and low toxicity were synthesized and showed a positive modulation of the bacterial community in aquaculture water ( Zhang et al, 2022 ). In this study, the comprehensive evaluation of AVH-AgNPs effects on growth, antioxidation, immunity, gut health, and gut microbiota of zebrafish was carried out, which lays a theoretical foundation for the practical application of AgNPs in aquaculture.…”