Uso de aditivo nutricional comercial para juvenis de tambaqui (Colossoma macropomum) (CURVIER, 1818).

Abstract

In order for there to be good productivity in fish crops, the food must meet the nutritional requirements of the species and provide them with health in the face of the challenges of production systems. | In fact, in confinement systems, animals are often exposed to a number of stressors. The use of nutritional additives in aquaculture, such as probiotics, probiotics and symbiotics, has been common to improve host health by balancing the intestinal microbiota and, likewise, inhibiting the rampant use of antibiotics. It is in this context that the present study aimed to evaluate the use of a commercial nutritional additive based on probiotics and prebiotics in the performance of juveniles of tambaqui Colossoma macropomum and in the stress challenge to hypoxia. The first phase of the experiment consists of using the product to feed tambaqui at different levels of inclusion (0, 2, 4, 6 and 8g / kg of diet) for 45 days. Subsequently, a second phase was carried out, approved as a hypoxia test, in which the dissolved oxygen level of the tanks of all treatments were reduced to approximately 1mg / L for 48h, and then the system oxygenation was normalized, the recovery was verified. of fish in 24 and 48 hours. There was no fish mortality in any treatment in phases I and II of the experiment. The additive did not change between treatments in terms of performance, blood parameters and bowel morphometry at the end of the growth trial. The blood parameters glucose, hematocrit and triglycerides showed differences when comparing treatments with the initial samples, with glucose being higher in T4 and hematocrit and triglycerides being higher in all treatments at the end of the performance test. In the hypoxia challenge, the only blood parameters that showed interaction between the analysis time and additive concentration factors were hematocrit and glucose. The others had an effect mainly on the analysis time; with the exception of ALT, which had no effect for time. Plasma protein was the only variable that had an effect on the concentrations of the feed additive. Thus, it is concluded that the concentrations of the commercial nutritional additive tested in this study do not provide changes in performance and in blood and intestinal morphometric variables for tambaqui juveniles. In situations of hypoxia stress, the tested concentrations of the additive lead to changes in blood parameters, especially for glucose and hematocrit