Optimization of the sublethal dose of silver nanoparticle through evaluating its effect on intestinal physiology of Nile tilapia (Oreochromis niloticusL.)

Abstract

Silver nanoparticles (SNPs) are widely used in a variety of biomedical and consumer products as an antimicrobial additive. The present study was conducted to evaluate the impacts of low-dose SNPs on intestinal physiology of tilapia (Oreochromis niloticus L.) for assessing its apparent environmental risk due to extensive commercial use. SNPs were synthesized by a chemical reduction method yielding 1-27 nm oval shaped particles. Early fingerlings of tilapia were exposed with two sublethal concentrations (0.8 and 0.4 mg L(-1)) of SNPs for twenty one days period and its impact on the intestinal physiology was evaluated by histochemistry, catalase expression, glutamate dehydrogenase activity, SDS-PAGE and gut micro flora count. Histological analysis showed thinning of intestinal wall, swelling on mucosal layer and immunohistochemical assay exhibited an enhanced catalase expression in SNPs treated fishes. Gut microflora count elicited a dose-dependent depletion and a variable SDS-PAGE profile followed by significant (P < 0.05) elevations in glutamate dehydrogenase activity in SNPs-treated fishes. This study was designed to provide a better understanding of environmentally acceptable, dose-dependent SNPs delivery in fishes and to formulate guidelines in aquatic toxicology.

Analysis of hematologic alterations, immune responses and metallothionein gene expression in Nile tilapia (Oreochromis niloticus) exposed to silver nanoparticles

“…The present results were relatively different from those of Sarkar et al (2015) most likely due to the different: (1) AgNP preparations used, (2) stabilizers/dispersants added, (3) sizes of the AgNP, (4) weights of the fish; and, (5) routes of exposure. While host size/route of exposure are key factors for any difference in outcomes, the studies of Jeong et al…”

“…Previously, Sarkar et al (2015) reported an acute toxicity (LD 50 ) of 1-27 nm AgNP in Nile tilapia prefingerlings (0.53 [± 0.10] g) of % 8 mg/L. The present results were relatively different from those of Sarkar et al (2015) most likely due to the different: (1) AgNP preparations used, (2) stabilizers/dispersants added, (3) sizes of the AgNP, (4) weights of the fish; and, (5) routes of exposure.…”

Gut Dysbiosis in Animals Due to Environmental Chemical Exposures

“…Early fingerlings of tilapia ( Oreochromis nilticus L .) exposed to one of two sub-lethal concentrations of AgNPs (0.4 and 0.9 mg/L for 21 days) demonstrated pathological changes in the intestines and gut microbiome disruptions (Sarkar et al, 2015 ). Histopathological analysis of the intestines showed reduced thickness of the intestinal wall, mucosal swelling, and increased catalase expression in AgNP-treated fish.…”

Review of the effects of silver nanoparticle exposure on gut bacteria

“…Another study showed that AgNPs altered bacterial evenness (α-diversity) and populations (β-diversity) and increased the ratio of Bacteroides to Firmicutes in a dose-dependent manner (van den Brule et al, 2016). Similarly, Sarkar et al (2015) detected dose-dependent changes in the gut microbial population of AgNP-exposed fish. At higher concentrations, NPs are more likely to cluster into multi-unit structures, potentially altering their biological interactions and effects (Williams et al, 2015).…”