Dietary Monosodium Glutamate Supplementation During The Feed Training Of Pacama (Lophiosilurus Alexandri): Growth Performance And Intestinal Histomorphometry

Feed training of carnivorous fish is a delicate and stressful process. Thus, feed additives that reduce stress and encourage fish consumption could improve training efficiency. Therefore, the aim of this study was to evaluate monosodium glutamate (MSG) dietary supplementation during pacama (Lophiosilurus alexandri) feed training through growth performance and intestinal histomorphometry. Fish were trained by the method of gradual diet transition, using five diets with increasing proportions of commercial diet and decreasing proportions of gelatin. A quadruplicate experimental design was performed with seven treatments, consisted in diets supplemented with different levels of MSG (0.0; 2.0; 8.0; 16.0; 29.0; 34.0 and 42.0 g/kg). Pacama (0.17 +/- 0.01 g) were distributed in 28 tanks (30 fish per tank) and trained for 41 days with the experimental diets. There were no effects (p > .05) of MSG on growth performance and feed training indices. However, fish trained with diets supplemented with 42.0 g/kg of MSG presented higher number of goblet cells in the anterior portion of intestine (p < .05). These results demonstrate that MSG did not act on growth performance and feed training efficiency of pacama, and high levels of MSG can cause dietary stress on fish intestinal mucosa.