Replacement of soybean meal by linseed meal in diets for piava (Leporinus obtusidens)

The aim of this study was evaluate the replacement of soybean meal by linseed meal on growth of piava juveniles. The experiment was carried on fish farming laboratory of UFSM/CESNORS, on March to April, 2011. They were used 360 fish, (initial weight = 9.0 +/- 2.5 g), which placed in a water re-use system composed by 15 tanks (250L), with mean temperature in the morning = 20.3 +/- 1.62 degrees C and in the afternoon = 21.4 +/- 1.42 degrees C, during 30 days. It were testes five diets with volumetric levels of soybean meal replace (0, 25, 50, 75 e 100%). The use of the linseed meal provided same performance to the fish. The weight, total length, standard length, relative weight gain, condition factor and specific growth rate of the piavas were not affected by treatments (P > 0.05). Similarly, the plasmatic glucose, body protein deposition and chymotrypsin enzyme no showed differences. The body lipid deposition was best expressed by the cubic polynomial regression model (P < 0.05). The inclusion of linseed meal increased the amount of the trypsin enzyme (P < 0.05). It concludes that the linseed meal can be used as protein source in diets for piava.