Dietary Photoprotective Compounds Ameliorate UV Tolerance in Shrimp (Pleoticus muelleri) through Induction of Antioxidant Activity

Abstract

The aim of this study was to determine the effects of ultraviolet radiation (UVR) on bioaccumulation of UV-absorbing compounds acquired through the diet, in larvae and postlarvae of Pleoticus muelleri, and to assess tissue antioxidant activity, survival, and development. Mysis stage I were exposed to two artificial radiation treatments: M-PAR (photosynthetically active radiation, range=400-700nm) and M-PAR+UVR (280-700nm). The experimental larvae received a mixed dietary treatment of Artemia persimilis and the microalga Pavlova lutheri, reared under two radiation regimes: PAR (D-PAR) and PAR+UVR (D-PAR+UVR). Shrimp from all treatments reached 8 d postlarval stage (PL8), except those under M-PAR+UVR treatment fed the D-PAR-cultured algae, which had 0% survival. Larvae in M-PAR+UVR and M-PAR treatments fed with D-PAR+UVR diet presented the highest survival rates (70 and 75%, respectively), with 37 and 41% increase in PL size. UV-absorbing compounds were detected in microalgae and PL subject to PAR+UVR treatments. Antioxidant activity, quantified by measuring the free-radical 1,1-diphenyl-2-picrylhydrazyl in homogenates of PL8, decayed drastically under radiation treatment M-PAR+UVR fed with algae of the D-PAR+UVR treatment. It is concluded that the bioaccumulation of UV-absorbing compounds and the highest antioxidant activity in PL could improve the biochemical and photophysiological responses of shrimp under UVR stress.