Effect of sulfated polysaccharides from red marine algae on Litopenaeus vannamei post-larvae submitted to the saline stress test

Abstract

The experiment was carried out to evaluate the effect of the administration of sulfate polysaccharides (SP) extracted from marine red algae Champia feldmannii, Halymenia pseudoforesia and Gracilaria birdiae, in the survival of Litopenaeus vannamei shrimp postlarvae (PL’s), submitted to the saline stress test in order to assess their quality. The SP were administered, via immersion, during six days, in concentrations 0.0 mg.L-1 (Control); 1.0 mg.L-1and 2.0 mg.L-1 (C. feldmannii); 2.0 mg.L-1 and 4.0 mg.L-1 (H. pseudoforesia), 2.0 mg.L- 1 and 4.0 mg.L-1 (G. birdiae), and the stress test carried out after the administration period. Therefore, 100 individuals from each treatment, acclimated to salinity 30, were transferred to recipients containing freshwater, where they stayed for one hour, and then restored again to original condition for 30 more minutes. The procedure was repeated four times for each treatment, being recorded the number of survivors at the end of the trials. Survival average values were submitted to Analysis of Variance (ANOVA) and Tukey Test (α=0.05). Higher survival was observed for G. birdiae 2.0 mg.L-1 treatment (94.36%), which was significantly higher than the lowest values recorded on Control (76.75%), and C. feldmannii 1.0 mg.L-1 and 2.0 mg.L-1 (75.37% and 74.94%) treatment. The results show that G. birdiae (2.0 mg.L-1) SP ascribed a greater resistance to the L. vannamei PL’s, submitted to saline stress, suggesting a possible protector effect of this compound, which should be further investigated.