Oral Toxicokinetics, Tissue Distribution, and 28-Day Oral Toxicity of Two Differently Manufactured Food Additive Silicon Dioxides

Oral Excretion Kinetics of Food-Additive Silicon Dioxides and Their Effect on In Vivo Macrophage Activation

A food additive, silicon dioxide (SiO2) is commonly used in the food industry as an anti-caking agent. The presence of nanoparticles (NPs) in commercial food-grade SiO2 has raised concerns regarding their potential toxicity related to nano size. While recent studies have demonstrated the oral absorption and tissue distribution of food-additive SiO2 particles, limited information is available about their excretion behaviors and potential impact on macrophage activation. In this study, the excretion kinetics of two differently manufactured (fumed and precipitated) SiO2 particles were evaluated following repeated oral administration to rats for 28 d. The excretion fate of their intact particles, decomposed forms, or ionic forms was investigated in feces and urine, respectively. Monocyte uptake, Kupffer cell activation, and cytokine release were assessed after the oral administration of SiO2 particles. Additionally, their intracellular fates were determined in Raw 264.7 cells. The results revealed that the majority of SiO2 particles were not absorbed but directly excreted via feces in intact particle forms. Only a small portion of SiO2 was eliminated via urine, predominantly in the form of bioconverted silicic acid and slightly decomposed ionic forms. SiO2 particles were mainly present in particle forms inside cells, followed by ionic and silicic acid forms, indicating their slow conversion into silicic acid after cellular uptake. No effects of the manufacturing method were observed on excretion and fates. Moreover, no in vivo monocyte uptake, Kupffer cell polarization, or cytokine release were induced by orally administered SiO2 particles. These finding contribute to understanding the oral toxicokinetics of food-additive SiO2 and provide valuable insights into its potential toxicity.

Management of the poultry red mite Dermanyssus gallinae with physical control methods by inorganic material and future perspectives

Poultry red mite (PRM), the ectoparasitic mite Dermanyssus gallinae found in laying hen farms, is a significant threat to poultry production and human health worldwide. It is a suspected disease vector and attacks hosts' other than chickens, including humans, and its economic importance has increased greatly. Different strategies to control PRM have been widely tested and investigated. In principle, several synthetic pesticides have been applied to control PRM. However, recent alternative control methods to avoid the side effects of pesticides have been introduced, although many remain in the early stage of commercialization. In particular, advances in material science have made various materials more affordable as alternatives for controlling PRM through physical interactions between PRM. This review provides a summary of PRM infestation, and then includes a discussion and comparison of different conventional approaches: 1) organic substances, 2) biological approaches, and 3) physical inorganic material treatment. The advantages of inorganic materials are discussed in detail, including the classification of materials, as well as the physical mechanism-induced effect on PRM. In this review, we also consider the perspective of using several synthetic inorganic materials to suggest novel strategies for improved monitoring and better information regarding treatment interventions.