Exigência de proteína bruta na dieta de alevinos e juvenis do ornamental Amazônico acará severo (Heros severus) (Heckel, 1840)

Abstract

Aquaculture is the practice of create a controlled manner aquatic organisms and is divided into two segments: food and ornamental purposes. Among the contributing organisms to the diversity of Brazilian Amazon ornamental fish fauna, it is severum (Heros severus). When bred in captivity, accepts all kinds of feed industrialized, nevertheless, are still unknown the nutritional requirements for species, including the protein requirement. There were two experiments in order to evaluate the requirement of crude protein (CP) in the fingerlings diet and juvenile Heros severus. In both experiments was test five isocaloric diets (3,200 kcal DE / kg) with five levels of CP (28, 32, 36, 40 and 44% CP). In the experiments, 75 fingerlings and 100 juveniles were distributed in 15 and 20 aquariums with a volume of 30L and 50L, respectively, in a completely randomized design with five treatments and three and four replications, respectively, and the aquarium the experimental unit. During 105 days, the fingerlings and juveniles were fed at a rate of 10 and 3% of body weight three and twice daily, respectively. There wasn’t significant effect of CP levels in the diet on survival, hepatossomatic index, viscerossomatic and moisture body for fingerlings (P>0.05). There quadratic effect of weight gain, length, specific growth rate, feed intake and feed conversion with increasing dietary crude protein levels (P<0.05), estimating values 41.86; 40.42, 41.29; 39.60; 43.54% CP, respectively. There was quadratic effect of body protein, lipid and ash body, with increasing levels of crude protein diet, estimating values 40.64; 37.77 and 37.50% CP, respectively. There was not significant effect of dietary protein levels on the survival of juveniles (P>0.05). It was observed quadratic effect of weight gain, specific growth rate, feed conversion, protein efficiency rate and hepatossomatic rate of juveniles (P<0.05), estimating values of 37.03; 37.20; 35.13; 35.85; 38.78% CP, respectively. The feed intake showed a linear increase (P<0.05) with increased levels of dietary protein. There was a linear decrease (P<0.05) viscerossomatic rate with increasing levels of dietary protein. Blood glucose and hematocrit showed lower values (P<0.05) in fish fed diet with lower content protein. Based on performance, efficient use of nutrients and body condition indices fingerlings and juveniles of severum, estimated levels from 37.77 to 43.54% and from 34.74 to 38.78% CP, respectively.