Spatoglossum schroederi em juvenis de Litopenaeus vannamei

Abstract

Stress is the most powerful immunesuppressor agent on carciniculture, causing the decrease of shrimp’s natural defenses, leaving them weakened and susceptible to contaminations by pathogens. Thus, it is of fundamental importance to the success of the activity the development of strategies that aim to turn these animals more resistants. A possible solution that has been studied is the use of immunostimulant compounds such as the sulfated polysaccharides (SP) from marine algae. The present study evaluated the effect of the administration of SP extracted from the brown alga Spatoglossum schroederi, in survival and growth of Litopenaeus vannamei juveniles, under stress conditions by hypoxia. The SP were daily administered, for 33 days, through immersion, in concentrations 0.0 (control); 0.5; 1.0 e 2.0 mg L^-1, with four replicates each. The stress was induced through temporary suppression of the aeration, during five hours, in the 23°; 24° and 25° day. Average values were submitted to Analysis of Variance and Tukey Test (p<0.05). The survival of shrimps administered with the higher dosage was significantly higher than the others (p=0.0101), at the end of the experiment. No significant differences were observed between the treatments, in relation to growth, in the four biometries held. Despite the positive effect noted, further studies should be carry out, in order to optimize the time and method of administration and the ideal dose to be used. It should be also evaluated the immunostimulant efficiency of the compound through specific studies using animals haemolymph and muscle tissue.