Densidade de estocagem e fontes energéticas vegetais no cultivo intensivo de jundiá e carpa húngara

Abstract

This work was carried out to evaluate the growth, metabolic parameters and carcass characteristics of jundiá and common carp in polyculture submitted to two stocking density and the inclusion of plant-energy sources in the diets of this species in monoculture. Two experiments were conducted using water re-use system. In the first experiment (29 days), fish (75% jundiá and 25% carp) were stocked in density 16 or 40 fish/tank (57 or 143 fish/m3) in four replicates. Jundiás and carps presented initial weight of 24.39±0.54 g and 27.73±0.22 g, respectively. Animals were fed twice daily with the same diet. The plasma cortisol level and the performance parameters: weight (W), coefficient of variation in weight, total length (TL) total biomass (TB), condition factor (CF), specific growth rate (SGR), feed conversion rate (FCR), daily weight gain (DWG) and relative weight gain (RWG) were evaluated. Both species had no significant differences in growth parameters. Carp juveniles rearing to density 57 fish/m3 had an increment of the plasmatic cortisol level. In the second experiment (60 days), the fish (jundiá = 5.59±0.06 g and carp = 5.82±0.14 g) were stocked (40 fish/tank) in monoculture, and three diets were evaluated with inclusion of husked oat or defatted rice bran stabilized (FADE) and control diet (wheat bran and corn), in three replicates. The diets were provided three times daily. Whole body composition, nutrient retention, metabolic parameters (triglycerides, total cholesterol, HDL cholesterol, total protein and albumin) and performance parameters (W, TL, TB, CF, SGR, FCR, DWG, RWG, daily consumption, protein efficiency rate), carcass yield and digestive indexes were determined. The jundiá and carp juveniles showed no significant difference in the performance parameters, carcass yield and digestive indexes. The jundiá juvenile fed with oats and FADE had the lowest levels of total cholesterol in serum. Concerning jundiás fed with FADE higher levels of triglycerides were observed. For jundiá, the lowest values of fat nutrient retention and in the composition of the whole fish were in the diet with oats. When carp juveniles were treated with FADE lower levels of total cholesterol were observed, however, a higher fat content in the composition of whole fish was seen when compared with carps of diet with oats. The lower retention of body fat in carp was observed in the treatment with oats. We can conclude that the highest stocking density evaluated of 143 fish/m3 does not affect the performance of jundiá and carp in polyculture and provides greater productivity per area. The inclusion of 20% of husked oats or defatted rice bran causes changes in the metabolism and carcass composition, but it does not affect the performance of the jundiá and carp thus they can be used as alternative ingredients in the formulation of diets for these species.