Inclusão de levedura na ração de juvenil de matrinxã

Abstract

The matrinxã (Brycon amazonicus) has excellent production characteristics, however the high cost of the feed remains an obstacle for fish farming. One of the alternatives to make your production cheaper is the use of unconventional ingredients in the feed. Sugarcane yeast (Saccharomyces cerevisiae), residue from sugar and alcohol industries is a good option. The aim of this study was to determine the best level of inclusion of sugarcane yeast in matrinxã ration due to the influence on zootechnical performance, feed and production costs, hematological responses and resistance to the induced by the bacterial challenge. The study was conducted at the Fish Farming Sector of Embrapa Amazônia Ocidental, Manaus, Amazonas, Brazil. Six experimental isonitrogenated and isoenergetic diets with levels of 0, 10, 20, 30, 40 and 50% of yeast inclusion were elaborated. Fish with an initial average weight of 10.5 ± 0.4 g were used, allocated in a system of 70 L boxes in a system of water renewal and aeration by means of a radial compressor, with four repetitions per treatment and 15 fish per repetition, they were fed for a period of 60 days. Survival, feed intake, final weight, weight gain, apparent feed conversion and specific growth rate were evaluated. In the final biometry, three fish per repetition were anesthetized, where blood was collected by puncturing the caudal vessel and then were slaughtered to collect data on vicerosomatic relationships, hepatosomatic relationships and visceral fat indexes. The rest of the fish were submitted to a bacterial challenge with 1 mL of a solution containing the bacterium Aeromonas hydrophila per fish, at a concentration of 1.14x108 bacteria. mL-1 by intraperitoneal injection, where survival was observed for a period of 96 hours. All treatments, before the bacterial challenge, showed survival above 90% and the inclusion of up to 40% yeast in the diet did not show significant differences in the final weight, weight gain, apparent feed conversion and in the specific growth rate and with based on the polynomial regression, the level of 35.6% of yeast in the feed showed the lowest production cost. In addition, the inclusion of up to 30% yeast reduced mortality in the bacterial challenge with A. hydrophila. In blood analyzes, only the number of erythrocytes showed changes between treatments. No treatment showed changes in the vicerosomatic relationship, hepatosomatic relationship and visceral fat index.