The effect of biofloc and clear water at low and high salinity concentration on growth performance and antioxidant response of wild juveniles of Atlantic white shrimp Penaeus setiferus

The effect of biofloc (BFT) and clear water (CW) at low (ls) and high-water salinity (hs) in wild juveniles of Penaeus setiferus were evaluated. Four treatments were implemented: hsBFT, lsBFT, hsCW, and lsCW. After 45 days, final weight (FW), weight gain (WG), hepatosomatic index (HSI), and survival rate (SR) were evaluated. Antioxidant activity in muscle and hepatopancreas were measured: superoxide dismutase (SOD), catalase (CAT), glutathione-S transferase (GST), lipid peroxidation (LPO), protein oxidation (PO). The FW and SR was low for lsCW (P < 0.05), whereas the WG and HSI was high in hsBFT and lsBFT (P < 0.05). The integrative biomarker response index (IBR) showed differences between muscle (M) and hepatopancreas (HP). Results showed an increase of SOD and CAT measured from HP for lsBFT treatment. For M, CAT and GST were high only in BFT (regardless of the water salinity). LPO determined from M and HP recorded the high values at hs and ls, respectively. The PO determined in HP showed substantial damage in BFT (regardless of the salinity), whereas the same determination from M was only important for lsCW treatment. When the analyses of variance (ANOVA) were performed, SOD, LPO, and PO were significant in response to salinity (P < 0.05). In contrast, for CAT, the higher activity was due to the rearing system and salinity interaction (P < 0.05). Results suggest that BFT could diminish the stress by stimulating the antioxidant system to maintain the redox balance through a higher enzyme activity and decrease damage in the proteins and lipids of the cells.

The seasonal entrance of Penaeus setiferus and Penaeus duorarum postlarvae into Términos Lagoon, Campeche, México

This study establishes the season for the immigration (recruitment) of Penaeus setiferus and P. duorarum postlarvae into Términos Lagoon, México, as well as the hydrological conditions that occur during this event. The abundance of postlarvae of both species was used to infer the reproductive period for each species. The zooplankton collection was carried out monthly for three years. The nets used were 50 cm in diameter, 1.5 m in length and 505 μm mesh size, and temperature and salinity were measured with an YSI. The fluvial discharges were taken from Comisión Nacional del Agua (CONAGUA). The harmonic pattern variation (HPV) was analyzed for each variable (density of postlarvae, salinity, temperature and fluvial discharge). A cycle was analyzed and divided into two episodes (rise and descent) to estimate the HPV of each postlarval species. The entrance of both postlarval species starts from June to September, with higher density in August, which decreases from October to May, with the lowest density in March. The first episode was established from June to August and the second episode in September. During the first episode the hydrological conditions were: high salinity (34), a warm temperature (30ºC) and low accumulated fluvial discharge (2,828 m3 s-1), while, in the second, they were low salinity (28), a moderately warm temperature (29ºC) and high accumulated fluvial discharge (3,934 m3 s-1).