Toxic and bioaccumulative effects of zinc nanoparticle exposure to goldfish, Carassius auratus (Linnaeus, 1758).

The widespread use of produced metal oxide nanoparticles (NPs) has increased major concerns about their impact on human as well as aquatic animal health. The present study shows that exposure to different concentrations of zinc oxide (ZnO) NPs led to high accumulations of Zn ions in the metabolic organs of fish (liver and gills), resulting in severe oxidative stress in Carassius auratus. The goldfish (C. auratus) was chosen as an aquatic species for the evaluation of the potential toxicity of aqueous ZnO-NPs (Treatments of hemoglobin and neutrophils (0, 0.5, 1, and 1.5 mg L- 1) following 14 days of exposure. A range of histological and hematological factors were examined. Exposure to the NPs produced significant reduction of red blood cell and white blood cell counts, hematocrit) were found to produce no significant differences in lymphocyte, monocyte, and eosinophil counts; as well as the mean corpuscular hemoglobin concentrations index (P > 0.05). Moreover, the results revealed significant alterations in serum biochemical parameters, hepatic enzyme levels, and immune and antioxidant responses; except for total protein and superoxide dismutase (SOD) of C. auratus exposed to ZnO-NPs, particularly at the 1 and 1.5 mg L- 1 concentrations. Fish exposed to 1 and 1.5 mg L-1 ZnO-NPs displayed a significant reduction in alternative complement pathway activity, lysozyme, and total protein contents of mucus compared to those in the control group. The results showed that hepatic SOD and catalase, and gill catalase activity were significantly decreased, and their malondialdehyde levels increased at 1 and 1.5 mg L-1 ZnO-NPs compared to the control group (P < 0.05). Significant accumulations of ZnO-NPs were observed in the liver, kidney, and gill tissues of fish leading to severe histopathological alterations in these organs. These results suggest that water-borne ZnO-NPs can easily accumulate in metabolic organs and lead to oxidative stress and destructive effects on the physiological features of C. auratus.

Integration of Morphometrics and Machine Learning Enables Accurate Distinction between Wild and Farmed Common Carp.

Morphology and feature selection are key approaches to address several issues in fisheries science and stock management, such as the hypothesis of admixture of Caspian common carp (Cyprinus carpio) and farmed carp stocks in Iran. The present study was performed to investigate the population classification of common carp in the southern Caspian basin using data mining algorithms to find the most important characteristic(s) differing between Iranian and farmed common carp. A total of 74 individuals were collected from three locations within the southern Caspian basin and from one farm between November 2015 and April 2016. A dataset of 26 traditional morphometric (TMM) attributes and a dataset of 14 geometric landmark points were constructed and then subjected to various machine learning methods. In general, the machine learning methods had a higher prediction rate with TMM datasets. The highest decision tree accuracy of 77% was obtained by rule and decision tree parallel algorithms, and "head height on eye area" was selected as the best marker to distinguish between wild and farmed common carp. Various machine learning algorithms were evaluated, and we found that the linear discriminant was the best method, with 81.1% accuracy. The results obtained from this novel approach indicate that Darwin's domestication syndrome is observed in common carp. Moreover, they pave the way for automated detection of farmed fish, which will be most beneficial to detect escapees and improve restocking programs.

Effect of Dietary Lactobacillus casei on Physiometabolic Responses and Liver Histopathology in Common Carp (Cyprinus carpio) After Exposure to Iron Oxide Nanoparticles.

A 60-day feeding trial was performed to assess the dietary effect of Lactobacillus casei as a probiotic supplement on some serum biochemical parameters and liver histopathology in common carp fry after exposure to iron oxide nanoparticles (IoNPs). Six treatments were prepared as follows: control (no IoNP exposure and no dietary probiotic), P6: 106 CFU/g probiotic diet, P7: 107 CFU/g probiotic diet, NPs: 0.15 mg/l IoNPs, NPs + P6: 0.15 mg/l IoNPs with 106 CFU/g probiotic diet, and NPs + P7: 0.15 mg/l IoNPs with 107 CFU/gprobiotic diet. Based on the results, serum aspartate aminotransferase and alanine aminotransferase levels were significantly increased in 0.15 mg/l IoNPs, P7, and NPs + P6 treatments compared to the control group. In addition, the examination of antioxidant enzymes showed a significant increase in the levels of cortisol and glutathione S-transferase as well as malondialdehyde level. IoNPs also caused significant histopathological changes in the fish liver during the experiment such as hyperemia in sinusoidal spaces, hepatocytes vacuolation and necrosis, pyknosis, and disruption of hepatic lobules and atrophy. Results revealed the protective effects of dietary L. casei to mitigate the adverse impacts of IoNPs on the physiological processes of common carp.

Protective effect of dietary vitamin E on immunological and biochemical induction through silver nanoparticles (AgNPs) inclusion in diet and silver salt (AgNO3) exposure on Zebrafish (Danio rerio).

The present study evaluated silver nanoparticle (AgNPs) toxicity using biomarkers of oxidative and metabolic stress, immunological impairment and cellular damage in zebrafish (Danio rerio), as well as the optimal dose of vitamin E neutralizing undesirable effects. Fish were fed for ten days and eight study groups were investigated: controls, AgNPs exposure alone (1.5 mg L-1) and combined with three different vitamin E doses (1.5 mg L-1 of AgNPs + vitamin E 100, 200 or 400 mg kg-1 of food), also one positive control group exposed to AgNO3 alone or combined with the same vitamin E doses. D. rerio exposed to AgNPs alone or combined with the lower vitamin E dose showed overall worse results in comparison with the control groups and the groups combining nanoparticles and 200 or 400 mg kg-1 of food of vitamin E-supplemented diet. AgNPs caused cell impairment by increasing LDH activity and cortisol levels, generated oxidative stress by inhibiting SOD and CAT activity and immunosuppression by inhibiting ACH50 and lysozyme activity. The groups exposed to Ag salt showed the same response-pattern found for the NPs groups, reinforcing that Ag toxicity of AgNPs is mediated by Ag+. In conclusion, although AgNPs are toxic to Danio rerio, vitamin E supplementation at 200 or 400 mg kg-1 can act protectively against its toxic effects.