Abstract

PENA-NAVARRO, Nelson; VARGAS-CORDERO, Ruth  and  VARELA-MEJIAS, Alexander. Natural  products as stimulators of  immunological system  in  Litopenaeus  vannamei,  infected  with  Vibrio parahaemolyticus. Agron. Mesoam [online]. 2013, vol.24, n.1, pp.133-147. ISSN 2215-3608.

The   objective  was  to  determine  the immunological  response  of  Litopenaeus  vannamei  using mannan-oligosaccharides (T1), garlic (T2) and a compound from plant extracts (T3) after being  infected with Vibrio parahaemolyticus.  Two   bioassays  were  performed  with duration of six (1x106    CFU) and fourteen (3x106    CFU) days in the  Marine Sciences and Limnology Research Center, University of Costa Rica in 2011. Research used 120 shrimp for each experimental period, extracted from farms located in the Nicoya Peninsula. Weight gain  and feed conversion were evaluated after product’s dosage. After infection with V. Parahaemolyticus,  hemograms,  coagulation,  hemolymph’s bacteriology and accumulated mortality analysis were made. Immunological parameters showed no statistical difference (P>0,05) between treatments in any  period, however after six days, T1 showed 41,07 x10⁵  hemocytes/ml, coagulation of 34,40 s and 4,44x10³  CFU/ml. Throughout the fourteen day  period, T2 obtained the best values (55,76x10⁵   hemocytes/ml, coagulation of 34,20 s and 15,4x10³  CFU/ml). After 10 hours of inoculation, accumulated mortality presented fewer deaths in T1 and T3 (76,2%) at six days, whereas at 14 days was (93,2%) for T1. Weight gain and feed conversion presented statistical differences  (P<0,05)  only for the bioassay which lasted six  days, where T2 showed a 54,3 g biomass, an  increase in weight gain of 19,3% and feed conversion of 1,4.

Keywords : Shrimp immunology; immunostimulation; hemograms; bacterial infection; feed conversion.

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