Ecotoxicity evaluation of polymeric nanoparticles loaded with ascorbic acid for fish nutrition in aquaculture.

BACKGROUND: Ascorbic acid (AA) is a micronutrient essential for the mechanisms of reproduction, growth, and defense in fish. However, the biosynthesis of this micronutrient does not occur in fish, so it must be supplied with food. A difficulty is that plain AA is unstable, due to the effects of light, high temperature, and oxygen, among others. The use of nanoencapsulation may provide protection and preserve the physicochemical characteristics of AA for extended periods of time, decreasing losses due to environmental factors. METHOD: This study evaluated the protective effect of nanoencapsulation in polymeric nanoparticles (chitosan and polycaprolactone) against AA degradation. Evaluation was made of the physicochemical stability of the nanoformulations over time, as well as the toxicological effects in zebrafish (Danio rerio), considering behavior, development, and enzymatic activity. For the statistical tests, ANOVA (two-way, significance of p < 0.05) was used. RESULTS: Both nanoparticle formulations showed high encapsulation efficiency and good physicochemical stability during 90 days. Chitosan (CS) and polycaprolactone (PCL) nanoparticles loaded with AA had mean diameters of 314 and 303 nm and polydispersity indexes of 0.36 and 0.28, respectively. Both nanosystems provided protection against degradation of AA exposed to an oxidizing agent, compared to plain AA. Total degradation of AA was observed after 7, 20, and 480 min for plain AA, the CS nanoparticle formulation, and the PCL nanoparticle formulation, respectively. For zebrafish larvae, the LC50 values were 330.7, 57.4, and 179.6 mg/L for plain AA, the CS nanoparticle formulation, and the PCL nanoparticle formulation, respectively. In toxicity assays using AA at a concentration of 50 mg/L, both types of nanoparticles loaded with AA showed lower toxicity towards the development of the zebrafish, compared to plain AA at the same concentration. Although decreased activity of the enzyme acetylcholinesterase (AChE) did not affect the swimming behavior of zebrafish larvae in the groups evaluated, it may have been associated with the observed morphometric changes, such as curvature of the tail. CONCLUSIONS: This study showed that the use of nanosystems is promising for fish nutritional supplementation in aquaculture. In particular, PCL nanoparticles loaded with AA seemed to be most promising, due to higher protection against AA degradation, as well as lower toxicity to zebrafish, compared to the chitosan nanoparticles. The use of nanotechnology opens new perspectives for aquaculture, enabling the reduction of feed nutrient losses, leading to faster fish growth and improved sustainability of this activity.

Zein Nanoparticles Impregnated with Eugenol and Garlic Essential Oils for Treating Fish Pathogens.

The supply of food derived from aquaculture has increased significantly in recent years. The aim of this industrial sector is to produce sustainable products to meet the needs of consumers, providing food security and nutritional benefits. The development of aquaculture has faced challenges including disease outbreaks that can cause substantial economic losses. These diseases can be controlled using chemicals such as antibiotics. However, the indiscriminate use of these substances can have major negative impacts on human health and the environment with the additional risk of the emergence of resistant organisms. The present manuscript describes the use of phytotherapy in association with nanotechnology in order to obtain a more effective and less harmful system for the control of bacterial diseases in fish. Zein nanoparticles associated with eugenol and garlic essential oil were prepared through antisolvent precipitation and characterized. Zein nanoparticles are promising carrier systems as zein proteins are biodegradable and biocompatible and, in this way, good candidates for encapsulation of active ingredients. The system presented good physicochemical properties with an average particle diameter of approximately 150 nm, a polydispersity index lower than 0.2, and a zeta potential of approximately 30 mV. High encapsulation efficiency was obtained for the active compounds with values higher than 90%, and the compounds were protected against degradation during storage (90 days). The nanoparticle formulations containing the botanical compounds also showed less toxicity in the tests performed with a biomarker (Artemia salina). In addition, the systems showed bactericidal activity against the important fish pathogenic bacteria Aeromonas hydrophila, Edwardsiella tarda, and Streptococcus iniae in vitro. The present study opens new perspectives for the use of botanical compounds in combination with nanotechnology to treat fish diseases caused by bacteria, contributing to a more sustainable fish chain production.

Prenatal epoxiconazole exposure effects on rat postnatal development.

Although some studies have pointed out to embryo/fetal toxicity, knowledge about the potential toxicity of the fungicide epoxiconazole is still limited. Once the results of these previous studies have raised some concern, this study studied the effects of epoxiconazole maternal exposure on the physical endpoints in the development of rat pups. To accomplish that, the effects of epoxiconazole (50.0, 100.0, and 150.0 mg/kg) were examined when rats were exposed at two different developmental stages: during the first 6 days of pregnancy or in the organogenesis period (6-15 days). After parturition, pups were tested for growth and maturational milestones. Maternal exposure to the fungicide, independently of phase, resulted in significantly early mean time to vaginal opening and delayed time to testes descent in pups. Weight gain rate in pups and their mothers was not affected for the tested exposure period. The findings of this study emphasize that epoxiconazole maternal exposure may lead to alterations in developmental patterns in nursing pups, consistent with the known influence of epoxiconazole on steroid hormone synthesis.

Evaluation of neurodevelopmental effects on rats exposed prenatally to sulfentrazone.

Although some studies have pointed to embryo/fetal toxicity at treatment levels that were not maternally toxic, knowledge about the potential toxic effects of the herbicide sulfentrazone is still limited. Since the results of these studies have raised some concern, the present work studied the effects of sulfentrazone maternal exposure on the physical and neurobehavioral endpoints in the development of rat pups. To accomplish that, the effects of the herbicide sulfentrazone (25 and 50mg/kg) were examined at two different developmental stages in rats: during the first 6 days of gestation, or in the organogenesis period (6-15 days). After parturition, pups were tested in a developmental test battery including measures of growth, maturational milestones, and neurobehavioral development. Maternal exposure to the herbicide resulted in significant alterations of the postnatal age at which the developmental milestones of ear and eye opening and testes descent were observed. There was a reduced weight gain rate in pups and their mothers when treated during the gestational period at the highest dose tested. Also, the functional state of the rat pup nervous system at different stages of postnatal development showed some neurodevelopmental delays in righting reflex, negative geotaxis, grip response, and motor coordination-locomotion and rearing (21-90 days of life) in the treated groups. Herbicide genotoxicity was investigated in fresh leukocytes both in mothers and pups using the comet assay: the data did not show any significant genotoxic effect induced by the herbicide. The findings of this study emphasize that sulfentrazone maternal exposure may lead to some neuromuscular and behavioral deficits in nursing pups.

Neurodevelopmental effects of perinatal fenarimol exposure on rats.

Knowledge about the potential toxic effects of fenarimol, a widely used fungicide, is still limited. Fenarimol is an aromatase inhibitor and therefore can affect estrogen/androgen levels in vivo in rodents. In view of these facts, the aim of the present work was to study the effects of fenarimol maternal exposure during different critical phases in the development of central nervous system in rat pups, on early physical and neurobehavioral endpoints essential to their development. For that, the effects of the fungicide fenarimol (150 and 300 mg/kg) were examined at three different developmental stages in the rat: during the first 6 days of gestation, prenatal (15-21 days), or first 6 days of lactation. Three categories of the impact of fenarimol on neonatal growth and neurobehavioral development of offspring were assessed: (1) physical, (2) reflex and strength, and (3) motor coordination. Findings on the pups' physical development did not indicate any significant alterations of the postnatal age at which specific developmental milestones were observed (pinna detachment, development of the fur, eruption of the incisor teeth, opening of the ears and eyes and testes descent). However, there was a reduced rate of weight gain in pups of mothers treated during lactation related to the earlier testing time periods (1-23 days of life). The study of the functional state of the rat pup nervous systems at different stages of postnatal development revealed some neurodevelopmental delays in righting reflex, climbing and grip response and locomotion (20-90 days of life) in the treated groups. Taken together, findings of this study emphasize that, as a result of fenarimol maternal exposure, some neuromuscular and behavioral deficits in nursing pups may occur principally during the last gestational period and lactation. These results could be the basis for further studies on molecular actions of fenarimol in order to predict better the biological consequences of this fungicide.

Prenatal and perinatal fenarimol-induced genotoxicity in leukocytes of in vivo treated rats.

The identification of environmental compounds that have adverse effects on reproductive health and animal development is particularly challenging. Fenarimol, a systemic fungicide, is considered non or weakly genotoxic. However, its available toxicological data are controversial and incomplete. This study was conducted in rat in vivo to determine whether this compound (150 and 300 mg/kg) had adverse effects on DNA integrity in dams and pups after maternal subcutaneous exposure. The animals were exposed during early gestation (1-6 days), late gestation (last 6 days), or first 6 days of lactation. Findings on fenarimol genotoxicity showed an adverse effect when detected by the Comet assay, both in dams and pup, and state that animal sensitivity to fenarimol is higher during postnatal period. Since the DNA damage increases during the time of exposure (2 h to 6 days after the birth), our data on pups suggest that fenarimol can mainly act on cell DNA through direct exposure of litter via milk.