Níveis de farelo de milho em dietas para juvenis de Lophiosilurus alexandri

Abstract

Objective of this work was to evaluate the influence of dietary carbohydrate levels on the performance and metabolism of pacamã juveniles (Lophiosilurus alexandri). A total of 120 juveniles were used, with a mean initial weight of 20.85 ± 2.01 g, distributed in 20 aquaria of 40L in a recirculation system. The experimental design was completely randomized, with five treatments (5, 10, 15, 20 and 25% carbohydrate) and four replicates (aquaria). The duration of the experiment was 63 days. The parameters evaluated were performance, hepatosomatic index (HSI), viscerosomal index (IVS), intestinal morphometry, glucose, HDL, LDL, total cholesterol, triglycerides, amylase activity, glucose-6-phosphate dehydrogenase (G6PD) and malic enzyme. The carbohydrate concentrations in the diets affected the performance, decreasing the final weight and GPD of the animals that fed with more than 10% carbohydrate. CAA was significantly (P> 0.05) better in fish fed with 5% carbohydrate. The intestinal morphometry, the hepatosomatic and viscerosomatic index presented no significant difference (P> 0.05). Total cholesterol, HDL, LDL and triglycerides did not present statistical difference (P <0.05). Glucose presented a linear behavior, increasing with increasing carbohydrate levels. The activity of the amylase enzyme showed no significant difference between the treatments (P> 0.05). The activity of the malic enzyme presented a quadratic behavior, in which the fish fed with 5% of maize showed less activity. Treatments 10, 15, 20 and 25% provided similar activity in these subjects. The G6PD presented increasing linear behavior. The data from the present study suggest that levels above 10% of maize in pacamã juvenile diets resulted in poor performance, demonstrating that pacamã fails to modulate amylase activity in response to increased carbohydrate in the diet. Carbohydrate in the diet also favored the activation of lipogenesis.