Investigation on the mancozeb toxicity in adult zebrafish (Danio rerio).

Agriculture has gained increasing importance in response to the continuous growth of the world population and constant need for food. To avoid production losses, farmers commonly use pesticides. Mancozeb is a fungicide used in agriculture as this compound is effective in combating fungi that harm crops. However, this fungicide may also produce damage to non-target organisms present in soil and water. Therefore, this study aimed to investigate the influence of exposure to mancozeb on survival rate, locomotor activity, behavior, and oxidative status utilizing adult zebrafish (Danio rerio) as a model following exposure to environmentally relevant concentrations of this pesticide. The experimental groups were negative control, positive control, and mancozeb (0.3; 1.02; 3.47; 11.8 or 40 µg/L). Zebrafish were exposed to the respective treatments for 96 hr. Exposure to mancozeb did not markedly alter survival rate and oxidative status of Danio rerio. At a concentration of 11.8 µg/L, the fungicide initiated changes in locomotor pattern of the animals. The results obtained suggest that the presence of mancozeb in the environment might produce locomotor alterations in adult zebrafish, which subsequently disrupt the animals' innate defense mechanisms. In nature, this effect attributed to mancozeb on non-target organisms might result in adverse population impacts and ecological imbalance.

Recycled polyvinyl chloride microplastics: investigation of environmentally relevant concentrations on toxicity in adult zebrafish.

Recycled polyvinyl chloride (PVC) microplastics have been detected in the aquatic environment. These recycled microparticles contain chemicals that are released into the environment reaching different organisms. Although the problem of the presence of recycled PVC microparticles in the environment is evident, the toxicological consequences of this contaminant to exposed organisms remains to be better determined. The aim of this study was to investigate the toxicity attributed to exposure to environmentally relevant concentrations of recycled PVC microplastics in adult zebrafish (Danio rerio). The experimental groups were: negative control, vehicle control, positive control, and recycled microplastics (20 ± 5 µm) at 5, 10 or 20 µg/L. Zebrafish (D. rerio) were exposed to respective treatments for 96 hr. Locomotion and oxidative status parameters were measured and mortality recorded. The positive control group presented increased mortality rates and decreased locomotor activity. Animals from the vehicle group did not show marked differences. Finally, no significant disturbances were found in survival rate, locomotion pattern and oxidative status of animals exposed to recycled PVC microparticles at 5, 10 or 20 µg/L. Taken together our results suggest that recycled PVC microplastics in this particle size range do not appear to exert harmful effects on exposed adult D. rerio. However, these results need to be carefully observed due to limitations including size of particle and duration of exposure parameters that might affect ecological consequences. It is suggested that additional studies applying other particles sizes and chronic exposure are needed to more comprehensively verify the toxicity of the contaminant investigated here.

Micronized resveratrol shows promising effects in a seizure model in zebrafish and signalizes an important advance in epilepsy treatment.

Resveratrol is a natural non-flavonoid polyphenolic that has been emerging in epilepsy treatment. Despite its pharmacological properties, the poor bioavailability of resveratrol has been an important barrier that hinders its application as an anticonvulsant. The aim of this work was to improve resveratrol's anticonvulsant effects by micronizing this compound through supercritical fluid micronization technology, which promotes an increase of the particles' surface area and allows significantly reduced particle size to be obtained. We obtained commercial and micronized resveratrol and investigated the anticonvulsant effects of resveratrol as commercially found and micronized resveratrol in a pentylenetetrazole-induced seizure model in zebrafish (Danio rerio) larvae. Diazepam was used as the positive control. Also, animals had their locomotor and exploratory activity analyzed 24 h after the seizure occurrence. The occurrence of the tonic-clonic seizure stage was only prevented by diazepam and micronized resveratrol, unlike the non-processed compound. The seizure development was significantly slowed by diazepam and micronized resveratrol, while non-micronized resveratrol was not able to increase the latency of seizure stages. In addition, diazepam and micronized resveratrol prevented the deleterious effects of pentylenetetrazole-induced seizures on animals' locomotor and exploratory behaviour. Obtained data demonstrates that the micronization process potentiates the anticonvulsant effect of resveratrol. Micronized resveratrol achieved a similar effect to the classical drug diazepam, with the benefit that it may be a safe drug candidate to be used during the neurodevelopmental stage.