Effects of polyethylene and polyvinyl alcohol on growth and protease activity of Acanthopagrus schlegelii juveniles.

Many plastic products are used in aquaculture. Studying the toxicological effects of plastics differing in water solubility on marine organisms can provide valuable information. In this study, different amounts of polyvinyl alcohol (PVA) and polyethylene (PE) films were embedded in the feed and fed to Acanthopagrus schlegelii. After 1, 2, 4, and 8 weeks, the changes in percentage weight gain (PWG), feed efficiency (FE), pepsin activity (PA), and trypsin activity (TA) were observed. Either fed to PE or PVA, PWG, and FE of the experimental group were lower than those of the control group after eight weeks. Plastics level recovered from digestive tracts, feces, and water were higher in the PE groups than in the PVA groups. PA rose with increased feeding of plastics, but TA showed the opposite trend. TA activity decreased with increased feeding of plastics. Further analysis showed that TA was positively correlated with PWG.