The use of chitosan as an antioxidant in the feed of cultivated P. vannamei shrimp against oxidative stress induced by exposure to microplastics.

Microplastics (MP) are omnipresent in aquaculture and can induce several toxic effects, mainly oxidative stress. Therefore, alternatives to minimize these effects are welcome. In this study, chitosan (1 and 3 g/kg) was supplemented through the feed of farmed shrimp P. vannamei for 30 days. After this period, the shrimp were exposed to MP (0.5 mg/L) for 7 days. The results showed the presence of MP in hepatopancreas, gills and muscle. Hepatopancreas morphological alterations, as well as lipid peroxidation, a decrease in GSH level, and an increase in SOD activity indicated an oxidative stress that was reversed by chitosan. The muscle was also affected by MP, showing decreased CAT activity and increased SOD activity, though no lipid peroxidation was observed. In muscle, chitosan reversed the SOD increase to basal activity. The results obtained showed that chitosan was more effective against oxidative stress than in preventing accumulation and histological damage.