THE LPS FROM THE GRAM-NEGATIVE BACTERIA Pantoea agglomerans STIMULATES GROWTH AND IMMUNE RESPONSE IN JUVENILE RAINBOW TROUT (Oncorhynchm mykiss)

摘要

The aim of this study was to evaluate the effects of different inclusion levels of the LPS derived from Pantoea agglomerans in rainbow trout fingerlings considering the general condition, growth and immune status of the animals.Juvenile rainbow trout (4.2 ±0.1 g) were fed three diets, a commercial (Diet A; Futura~(TM), Aller Aqua, Denmark) and the same diet in which incorporated the LPS derived from P. agglomerans (RUBINUM SA). The fish were fed with 10 and 20 mg LPS/kg biomass (Diets B and C). The composition of all diets was: 64% protein, 12% fat, 11% ash and 0.5% fiber by manufacturer. The LPS was dissolved in fish oil and sprayed into the diet the manufacturing process of the extruded feed (Aller Aqua). Each diet was tested in triplicate (400-L tank, 125 fish/tank) for 93 days. Temperature, dissolved oxygen and pH values were 13.2 ± 0.2 °C, 8.0 ± 0.3 mg/L and 7.5 ± 0.01 (mean ± SD), respectively. The tanks were connected to a recirculation system (IRTAmar~R) to maintain water quality. The fish were fed to apparent satiation by automatic feeders. At the end of the trial, all fish were measured (standard length and weight) and 45 fish (15 per replicate) examined for body proximate composition, histological organization of the intestinal mucosa and analysis of immunological blood parameters (hemolytic complement, lysozyme, bacteriolytic activity and respiratory burst). The various parameters were compared between groups analyzed by ANOVA.