Uso de probiótico durante o transporte de juvenis de tambaqui (Colossoma macropomum) em sistema fechado

Abstract

The aim of this study was to evaluate the intestinal mucosal integrity and the effectiveness of addition of a probiotic as a potential stress reducer during the transport of tambaqui juveniles. In a completely randomized design with three treatments and seven replications, a control treatment (fish fed a commercial diet without probiotic) with was compared with two other treatments involving the use of a commercial probiotic incorporated into the diet or in the transport water. A total of 510 juvenile tambaqui (83.26 ± 28.14 g and 17.39 ± 1.90 cm) were distributed into three cement tanks. For 60 days, fish from the two tanks were fed a commercial diet, and the fish from the third tank received a commercial diet supplemented with a probiotic. After this period, the fish from each tank were divided into plastic bags and transported for four hours, receiving the following treatments: T1: commercial diet (control); T2: commercial diet and probiotic dissolved in the transport water (20 mg/L); T3: commercial diet supplemented with probiotic (1.0 g/kg diet). Before transport (baseline), and 24 and 96 hours after transport, fish from each treatment were euthanized and their intestine was removed for morphological and histological evaluation of the intestinal mucosa. In these same sampling times and immediately after transport, blood was collected to evaluate metabolic, hematologic, immunologic, and ionic parameters. The results were analyzed by ANOVA using the SAS software and data were expressed as means compared by Tukey’s test at 5% significance. In all treatments, the intestine length increased with increase in thefish size. Supplementation with probiotic (Bacillus spp.) had no effect on weight (g), relative weight (%), villus height and villus length of tambaqui challenged with transport. The stress response of the tambaqui fish was similar among the tested treatments, indicating that the probiotic used was not efficient in suppressing stress during transportation.