Effects of UV radiation on larval and postlarval stages of the argentine red shrimp, Pleoticus muelleri, using Artemia salina irradiate like food

MARCOVAL, M.A; FENUCCI, J.L.

Córdoba

Encuentro; Segunda Reunión de Fotobiólogos Moleculares; 2013

Grupo Argentino de Fotobiología

The aim of this study was to determine direct- and indirect (dietary) effects of ultraviolet radiation (UVR) on survival, development of larvae and postlarvae of the Argentine red shrimp, Pleoticus muelleri, and the bioaccumulation of UV-absorbing compounds through the diet. Mysis I larvae (MI) were incubated at a density of 200 L-1 in 4-L parabolic tanks under controlled temperature, pH and salinity conditions. The experimental design incorporated two radiation, and two dietary treatments (i.e. a 2×2 design). Larvae were exposed to two radiation treatments (n = 3), namely: a) M-PAB, in which uncovered experimental tanks received the total radiation spectrum (UVR 280-400 nm + PAR 400-700 nm); and b) M- PAR, in which containers were covered with Ultraphan film (opaque to UVR, Digefra, 50% transmission at 395 nm) to receive only PAR. UVR was generated from Q-Pannel UVA-340 lamps, and fluorescent bulbs provided PAR. Additionally, two experimental dietary treatments were considered: a) A-PAB, consisting of Artemia salina nauplii supplemented with Pavlova sp. [ microalgae commonly used in aquaculture (1) and known to produce UV-absorbing compounds (2)], and incubated under the PAB radiation regime; and b) A-PAR, consisting of nauplii, and Pavlova sp., incubated under the PAR regime. Experiments lasted until the Postlarval 5 (Pl5) stage. In order to determine larval physiological state and fitness, a stress or larval quality index (Qi) was calculated (3). All treatments reached the Pl5 stage, except M-PAB treatment fed A-PAR, whose survival was 0 % in the transition from the MIII to Pl1 stages. The M-PAB treatment fed A-PAB, together with the M-PAR treatment fed A-PAB, presented the higher survival rates (70 and 75 %, respectively), congruently with a 37 and 41 % increase in size. Moreover, in both combinations, larvae took 8 days to reach the Pl5 stage and presented Qi = 70 %. The induction of the synthesis of UV- absorbing compounds was detected spectrophotometrically in the microalgae, in A. salina, and in shrimp postlarvae subject to PAB treatments. We conclude that UV- absorbing compounds could bioaccumulate through the diet, possibly contributing to a photoprotective effect under UVR stress. Referencences 1- Brown M.R., Jeffrey S.W., Volkman J.K., Dunstan G. A., Aquaculture, 151,315, 1997. 2- Hannach G., Sigleo A.G., Mar.Ecol.Prog.Ser, 174, 204, 1998 3- Gaxiola G., Gallardo P., Simôes N., Cuzon G., Journal of the World Aquac. Soci. 41, 402, 2010