Effects of boric acid on the growth performance and nutritional content of rainbow trout (Oncorhynchus mykiss)

Effects of Boric Acid on Oxidative Stress Parameters, Growth Performance and Blood Parameters of Rainbow Trout (Oncorhynchus Mykiss)

Rainbow trout (Oncorhynchus mykiss) with a starting weight of 397.28 ± 3.21 g were fed different ratios (G1-0.00%, G2-0.010%, G3-0.025%, and G4-0.050%) of boric acid-supplemented feed for 140 days. The effects of dietary boric acid on oxidative stress parameters, growth performance, haematology and some biochemical parameters were investigated after the feeding period. The addition of boric acid to trout feed positively affected growth performance; the final weights of the groups were 928.15 ± 5.73 g, 955.87 ± 8.67 g, 994.24994,75 ± 7.46 g, and 976.80976,80 ± 6.26 g for the control group and the three experimental groups, respectively. The lowest feed conversation ratio (FCR) was 1.19 (G3) whereas the highest was 1.42 (G1). The lowest protein efficiency ratio was 1.63 (G1), while the highest was 1.95 (G3). In this study, it was observed that boric acid added to the feed changed muscle and blood oxidative stress parameters in rainbow trout, increased the growth performance of rainbow trout, and affected blood and biochemistry values.

Evaluation of Possible Toxic Effects of Boric Acid in Palourde Clam (Ruditapes decussatus) Through Histological Changes and Oxidative Responses

The extensive utilization of boric acid, particularly in industrial and agricultural sectors, also engenders concerns regarding the toxicity of boron and its derivatives. Particularly, the behavior of boric acid at increasing concentrations in aquatic ecosystems remains poorly understood. In light of these concerns, this study aimed to investigate the toxicity of boric acid in bivalves, which occupy a critical position in the food chain. Specimens of Ruditapes decussatus, which had not been previously exposed to any pollutants and were cultivated under controlled conditions, were subjected to three different concentrations of boric acid (0.05 mg/L, 0.5 mg/L, and 5 mg/L) in vitro for 96 h. Following the exposure period, the specimens were assessed for histological changes (the mantle, gill, and digestive gland) and specific oxidative parameters (the gill and digestive gland), including superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase, and lipid peroxidation (LPO). The research findings indicated that boric acid primarily induced oxidative damage at the applied concentrations and increased antioxidant levels (p < 0.05). Moreover, although no significant histopathological abnormalities were observed in the examined histological sections, subtle changes were noted. This study evaluated the potential adverse effects of boric acid on bivalves, which are crucial components of the aquatic food chain, utilizing histological and specific physiological parameters following its introduction into aquatic environments. It is anticipated that the findings of this study will contribute to the development of new insights and perspectives regarding the extensive use of boric acid.

Neutralization of iron oxide magnetic nanoparticle aquatoxicity on Oncorhynchus mykiss via supplementation with ulexite

Nowadays, the unique features of nanoparticles (NPs) have encouraged new applications in different areas including biology, medicine, agriculture, and electronics. Their quick joining into daily life not only enhances the uses of NPs in a wide range of modern technologies but also their release into the aquatic environment causes inevitable environmental concerns. On the other hand boron exhibits key physiological effects on biological systems. This research was designed for evaluating the toxicity of magnetite nanoparticles (Fe3O4-MNPs) on aquatic organisms and obtaining data for the information gap in this area. In this study, Rainbow trout (Oncorhynchus mykiss) was considered as an aquatic indicator, and trials were designed as Ulexite (a boron mineral, UX) treatment against exposure to Fe3O4-MNPs. Synthesized and characterized Fe3O4-MNPs were exposed to rainbow trouts in wide spectrum concentrations (0.005-0.08 mL/L) to analyze its lethal dose (LC50) and cytoprotective properties by UX treatment were assessed against Fe3O4-MNPs applications for 96 h. For the initial toxicity analysis, hematological parameters (blood cell counts) were examined in experimental groups and micronucleus (MN) assay was performed to monitor nuclear abnormalities after exposure to NPs. Biochemical analyzes in both blood and liver samples were utilized to assess antioxidant/oxidative stress and inflammatory parameters. Also, 8-hydroxy-2'-deoxyguanosine (8-OHdG) assay was used to investigate oxidative DNA lesions and Caspase-3 analysis was performed on both blood and liver tissues to monitor apoptotic cell death occurrence. When antioxidant enzymes in blood and liver tissue were examined, time-dependent decreases in activity were determined in SOD, CAT, GPx, and GSH enzymes, while increased levels of MDA and MPO parameters were observed in respect to Fe3O4-MNPs exposure. It was found that TNF-α, Il-6 levels were enhanced against Fe3O4-MNPs treatment, but Nrf-2 levels were decreased at the 46th and 96th h. In the 96th application results, all parameters were statistically significant (p < 0.05) in blood and liver tissue, except for the IL-6 results. It was determined that the frequency of MN, the level of 8-OHdG and caspase-3 activity increased in respect to Fe3O4-MNPs exposure over time. Treatment with UX alleviated Fe3O4-MNPs-induced hematotoxic and hepatotoxic alterations as well as oxidative and genetic damages. Our findings offer strong evidence for the use of UX as promising, safe and natural protective agents against environmental toxicity of magnetite nanoparticles.

Effects of glutamine on growth performance, nutrient content, fatty acid profile, and blood parameters of rainbow trout (Oncorhynchus mykiss)

In this study, different amounts of glutamine were added to the diet of rainbow trout, and they were then fed for a period of 90 days. The current research investigated the effects of glutamine on various aspects of rainbow trout, including growth performance, condition factor, viscerosomatic index, hepatosomatic index, carcass composition, fatty acid profile, hematological parameters, and biochemical parameters. The study's findings revealed that adding glutamine to the diet of rainbow trout had a beneficial impact on their growth features. The rainbow trout group that was fed a 2% concentration of glutamine experienced the most notable increase in growth rate. A statistically significant difference in growth was observed among all groups (p < 0.05). Adding glutamine to the diet increased the amount of protein and decreased the fat content in the flesh of the fish. Glutamine exerted an influence on the blood and biochemistry parameters of fish, as well as their fatty acid composition. In conclusion, the inclusion of glutamine in the diet of fish could potentially enhance their immune system, improve the quality of their muscles, and enhance their growth performance.

Exploring the mechanisms underlying the toxicity of boric acid against the land snail, Theba pisana

BACKGROUND

The land snail, Theba pisana, is one of the most important threats facing agriculture around the globe. Boric acid (BOA) is currently used as a safe alternative molluscicide to control land snails in sustainable agriculture, but the mechanisms of toxicity have not yet been investigated. The present study characterizes the lethal and sub-lethal (0.5 and 1 mg g^-1 ) toxic effects of BOA-contaminated food for 14 days by examining physiological, biochemical and histopathological indicators in T. pisana to understand the mechanisms underlying its toxic action.

RESULTS

BOA was found to be lethal against T. pisana with LC₅₀ values of 24.7 and 8.05 mg g^-1 after 3 and 7 days of exposure, respectively. BOA sublethal concentrations led to a significant reduction in food consumption and growth of snails after 14 days of exposure. BOA also caused a significant increase in testosterone levels, whereas an opposite effect was observed in estradiol levels. An increase in progesterone levels in snails in the 0.5 mg g^-1 BOA group and a decrease in the 1 mg g^-1 BOA group were observed after all exposure times. Moreover, the lipid peroxidation level and catalase activity were elevated, whereas acetylcholinesterase activity was inhibited in the treated snails. Alteration in glutathione-S-transferase activity was noticed after exposure to both sublethal concentrations. In addition, BOA induced histopathological alterations in the digestive gland of T. pisana.

CONCLUSION

Our findings provide novel insights into how physiological, biochemical and histopathological alterations can be used to explore the mechanisms underlying BOA toxicity against snails. © 2022 Society of Chemical Industry.

Unique metalloid uptake on microplastics: The interaction between boron and microplastics in aquatic environment

Boron pollution in the aquatic environment has a hazardous effect on human health and the ecosystem as a metalloid pollutant, and few researchers have focused on the potential interaction between boron and microplastics. We investigated the adsorption of boron on four types of microplastics (polyvinyl chloride (PVC), aged PVC, polystyrene (PS), and aged PS). The adsorption behavior was explored by kinetics, isotherm models, and several aqueous factors, including pH, humic acid, ionic strength (Na⁺), metal ion types (Mg²⁺, Ca²⁺, Cu²⁺, and Al³⁺), and the seawater environment. The adsorption capacities on microplastics were followed: aged PVC (0.91 mg/g) > aged PS (0.197 mg/g) > virgin PVC (0.1 mg/g) > virgin PS (0.005 mg/g). The adsorption kinetics and isotherm models suggested monolayer adsorption and chemisorption. Humic acid and high pH significantly inhibited the adsorption due to the complexation and hydrolysis of boric acid (B(OH)₃), respectively. The presence of metal ions may enhance or hinder adsorption, depending on the boron species, ion concentration, ion type, and microplastics categories. The unique interaction mainly depended on surface complexations of B(OH)₃ with oxygen-containing groups on microplastics surface. Because aged microplastics have more oxygen-containing groups, they can combine more B(OH)₃, and PVC can adsorb more boron due to the CCl bond and surface diffusion. In the aquatic environment, however, metal ions may occupy these binding sites, and the electrostatic force between borate ([B(OH)₄]^-) and microplastics will take precedence. In the simulated intestines of warm-blooded animals, we achieved the greatest boron desorption ratio on microplastics. This work explored the adsorption characteristics of boron by microplastics and revealed potential environmental risks of metalloid enrichment.