Metanauplii Research Articles

Toxicity evaluation of polypropylene microplastic on marine microcrustacean Artemia salina: An analysis of implications and vulnerability

Polypropylene microplastic particles are one of the predominant pollutants in marine ecosystems and their toxic effects are unknown in aquatic biota. The study aims to prepare the spherical shaped polypropylene microplastics (size range 11.86 μm–44.62 μm) and assess their toxic effects (1, 25, 50, 75 and 100 μg/mL) in various life stages (nauplii, metanauplii and juvenile) of marine microcrustacean Artemia salina within 48 h. In addition, microplastics ingestion by Artemia nauplii was proved by FTIR analysis. The results revealed, microplastics accumulation in their tract leads to change in their homeostasis, as followed increase in the oxidative burst causes mortality in nauplii (LC50 40.947 μg/mL) and meta nauplii (LC50 51.954 μg/mL). In juvenile, swimming behaviour was changed. Moreover, microplastic consumption disturbs the antioxidant biomarkers such as superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione –S- Transferase (GST) and reduces the neurotransmitter enzyme acetylcholinesterase (AChE) activity. In addition, histology of juvenile Artemia showed damage in epithelial cells. This study indicates that exposure to polypropylene microplastics is more harmful to zooplanktonic organisms of the marine ecosystem.

Effect on survival and growth (weight and length) of Ambystoma Mexicanum (Shaw Y Nodder, 1798) of three probiotics obtained from their gastrointestinal tract

The effect of probiotic strains (Lactococcus lactis; Lactobacillus sp and Bacillus subtilis), isolated from the intestinal tract of Ambystoma mexicanum on survival and growth of this amphibian was evaluated. 120 larvae with a weight of 3.0 ± 0.26 g and length of 1.5 ± 0.62 cm, were fed with probiotic strains (107 CFU mL-1) bioencapsulated in Artemia franciscana metanauplii. Diets were handled in triplicates (10 organisms per beaker) during 60 days. Every 15 days were measured and weighed to obtain the intrinsic growth rate (IGR) and absolute growth rate (AGR). Analysis of variance and Condition Factor was performed. Organisms that obtained a higher weight and length were fed with B. subtilis (5.86 ±0.42 g; 4.56 ±0.27 cm). Diets with L. lactis and B. subtilis presented the best Condition Factor (KM). Variance analysis showed significate differences (P<0.001) between all treatments. Axolotls fed with probiotics presented survival <85%, while control was 60%.