Resíduo intermediário de destilarias de álcool de arroz em dietas para jundiá (Rhamdia quelen)

Abstract

The present study aimed at assessing the zootechnical parameters, metabolic responses and body nutrient deposition in silver catfish (Rhamdia quelen) regarding partial substitution of fish meal to intermediary residue from rice alcohol distilleries (IRAD). A total of 375 silver catfish juveniles were distributed in 15 boxes of 125 L each (25 fish/box) connected with a water recirculation system during 60 days. Three isoproteic and isoenergetic diets (IRAD0: without IRAD addition, IRAD25 - 25% substitution of PB of fish meal with PB from IRAD, and IRAD50 - 50% substitution of PB of fish meal with PB from IRAD) were formulated. The animals were fed three times a day until apparent satiety. At the end of the experiment (60 days), zootechnical parameters (full length, total weight, weight gain, specific growth rate, feed conversion ratio, final biomass and food intake) and somatic indexes digestivesomatic, hepatosomatic and intestinal quotient were evaluated. Glucose, total proteins, albumin, total cholesterol and triglycerides in the blood, and glucose, glycogen, proteins and free amino acids in the hepatic tissue were also evaluated. In addition, the body composition of nutrients (moisture, ash, fat and protein), protein deposition and body fat were evaluated. Animals fed the IRAD0 presented significantly higher (P <0.5) total consumption, followed by treatments IRAD25 and IRAD50, respectively. Likewise, significant differences (P <0.05) were found for the final weight (FW), final biomass (FB), weight gain (WG) and specific growth rate (SGR), where treatment animals IRAD0 presented the best values in animal performance when compared to those submitted to IRAD25 and IRAD50 treatments, which in turn presented a significant reduction with the increasing inclusion of IRAD. The highest feed conversion rate (FCR) was observed for the IRAD50 treatment, differing from the treatments IRAD0 and IRAD25. The highest levels of glucose, total proteins and plasmatic albumin were observed in fish fed with IRAD50. The levels of hepatic glycogen, glucose, free amino acids and hepatic protein were higher in fish fed with IRAD50 diet compared to the animals that received the IRAD0 and IRAD25 diets. The IRAD0 treatment presented the highest level of PD, differing from IRAD50 treatment. The other evaluated parameters did not differ between them. Even though IRAD presented a high protein concentration, for this study, it negatively affected fish performance. Thus, further studies on assessing the protein quality of IRAD are necessary in order to effectively apply it on fish nutrition.