Fatty acid alteration in liver, brain, muscle, and oocyte of zebrafish (Danio rerio) exposed to silver nanoparticles and mitigating influence of quercetin-supplemented diet.

No to less effort has been made to assess the toxicity of silver nanoparticles (AgNPs) to lipid composition in biological systems and also to discover a mitigating agent against their oxidative stress. Hence, this research evaluated the antioxidant capability of quercetin (Qu) against silver nanoparticles (AgNPs) toxicity towards the lipid contents of ovarian, nervous, and hepatic systems as well as skeletal muscles. To this end, zebrafish (n = 180) were assigned into four experimental dietary groups: negative and positive controls, without Qu supplementation; Qu-200, 200 mg Qu per kg diet; and Qu-400, 400 mg Qu per kg diet. At the end of the feeding trial (40 days), the experimental groups, except the negative control, were exposed to sublethal concentration of AgNPs (0.15 mg L-1) for 96 h. As to the liver tissue of the positive and Qu-200 treatments, total polyunsaturated fatty acids (∑PUFA) decreased 3 times, as well as total high unsaturated fatty acids (∑HUFA) reduced about 30% and 50%, respectively. However, the brain ∑HUFA, predominated by DHA, enhanced in Qu-400 treatment. Interestingly, ∑MUFA, ∑PUFA, and ∑HUFA increased in the muscle of all treated groups, especially Qu-200 and Qu-400. The oocyte ∑MUFA content increased in the positive and Qu-200 treatments, whereas ∑HUFA reduced about 25%, 25%, and 20%, respectively, in the positive, Qu-200, and Qu-400 groups. Generally, the findings suggest that unsaturated acyl chains, particularly HUFAs, in the liver tissue and oocyte cell are highly susceptible to peroxidation or degeneration by AgNPs. More broadly, in the context of ecotoxicological risk assessment, the alteration in HUFAs and PUFAs of the liver and oocyte could impact on maternal and offspring health and consequently alter long-term population dynamics of aquatic animals.

Perturbation of fatty acid composition, pigments, and growth indices of Chlorella vulgaris in response to silver ions and nanoparticles: A new holistic understanding of hidden ecotoxicological aspect of pollutants.

This study assesses and compares the influence of silver nanoparticles (AgNPs) and silver nitrate (AgNO3) on the fatty acid composition, pigments, and growth indices of Chlorella vulgaris. Toxicity testing was carried at the estimated and/or above predicted environmental concentrations of AgNPs and AgNO3. AgNO3 treatments impaired the population growth of C. vulgaris about 2-183 times more than the respective AgNPs ones. The pigments displayed a concentration-dependent decrease in response to both forms of silver; however, AgNO3 displayed higher severity to the pigments than AgNPs. In exposure to 10 µg L-1 AgNO3, the contents of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid, respectively, demonstrated a reduction of about 5, 3, 4, and 4 times when compared with the same respective concentration of AgNPs. Total amounts of saturated (∑SFA), monounsaturated (∑MUFA), and polyunsaturated (∑PUFA) fatty acids as well as the ratio of unsaturated to saturated ones (Unsat./Sat.) displayed somewhat similar-concentration responses. ∑SFA exhibited a hormesis response, and ∑MUFA, ∑PUFA, and Unsat./Sat. did a decreasing trend with increasing concentration of AgNPs and AgNO3. Myristoleic acid, nervonic acid, and eicosadienoic acid revealed the highest sensitivity. Pearson analysis illustrated the highest correlation among myristoleic acid, eicosenoic acid, and nervonic acid as well as among palmitic acid, stearic acid, palmitoleic acid, and oleic acid. Taken together, AgNPs and the released ions could disrupt physiological health state of microalgae through perturbation in the fatty acid composition (especially MUFAs and PUFAs) and other macromolecules. These types of bioperturbations could change the good health state of aquatic ecosystems.

Effects of dietary b-glucan, mannan oligosaccharide, Lactobacillus plantarum and their combinations on growth performance, immunity and immune related gene expression of Caspian trout, Salmo trutta caspius (Kessler, 1877).

This study investigated the effect of individual and combination of dietary pre- and probiotics (ß-glucan, 3 mg/g; mannan oligosaccharide (MOS), 4 mg/g; and Lactobacillus plantarum; 108 CFU/mg diet) on growth performance, blood immune parameters, expression of immune related genes, and intestinal microbial of Caspian trout (Salmo trutta caspius). On the basis of feeding with immunostimulant diets, the fish were assigned into eight groups denoted as: control (basal diet), bß (basal diet + ß-glucan), bM (basal diet + MOS), bLp (basal diet + L. plantarum), bßLp (basal diet + ß-glucan + L. plantarum), bMLp (basal diet + MOS + L. plantarum), bMß (basal diet + MOS + ß-glucan), and bMßLp (basal diet + MOS + ß-glucan + L. plantarum). All of the immunostimulant diets, in general, reduced feed intake (FI) and food conversion ratio (FCR) and increased WG, PER, and final weight. Condition factor (CF) demonstrated the lowest level in the experimental group received bMßLp. Total lipid increased in the fish received the additives, especially bM and bMß. Ash content demonstrated significant increase in the fish fed on bß and bMßLp, whereas moisture content was reduced in the group fed with L. plantarum-supplemented diet. All immunostimulant diets enhanced the activity and levels of lysozyme, Immunoglobulin M (IgM), and serum alternative complement activity (ACH50); the highest value for these indices was observed in the groups fed with bMß, bMßLp, and bßLp. bMß-treated fish group displayed the highest cortisol and glucose levels. bM diet induced the highest mRNA transcription of TNF-α1 in head kidney, whereas bLp, bMß, and bMßLp showed no effect. IL1ß exhibited the greatest up-regulation, about 8.75 fold change, in response to the diet supplemented only with ß-glucan. bßLp and bß significantly enhanced the relative IL-8 mRNA expression in the head kidney (about 2.75 and 1.9 folds, respectively), yet in response to bMßLp treatment it showed a decrease of about 5.7 times lower than the control group. In addition, intestinal population of L. plantarum showed the highest loads in the groups fed on the diets which were treated with the probiotic. Taken together, combinational use of these immunostimulants enhanced humoral innate immune system, whereas their individual and combinational application could increase and decrease the transcription of inflammation-related genes, respectively.