Supplemented prebiotics in the feeding of Arapaima gigas juveniles raised in water-boxes with continuous mechanical aeration and water-boxes flow

Abstract

The study aimed to evaluate the effect on zootechnical performance and survival of pirarucu juveniles (Arapaima gigas) submitted to prebiotic supplementation in their diet. Were 120 juveniles of A. gigas acquired, acclimated in water-boxes with continuous aeration and water flow, and fed ad libitum four times a day, with a diet containing 55% crude protein. The 25.5 ± 3.5 g fish were distributed in 12 water-boxes of 500L (3 water-boxes/treatment and 10 fish/water-box). Juveniles were subjected to control (without prebiotics) and also subjected to three treatments A, B and C. The parasites found were observed under optical and scanning electron microscopy (SEM). Fish were distributed in completely randomized design water-boxes. The data obtained were evaluated by the Shapiro-Wilk and Bartlett’s tests (α=0.05). Then, they were submitted to ANOVA, and contrasted by the Tukey’s test (α=0.05). While the treatments were contrasted with each other by Dunn's test (α=0.05). The water quality parameters were kept adequate for A. gigas cultivation. In treatments, zootechnical performance and survival rate differed from each other, and were better than the control (p<0.05). Treatment A expressed the highest final weight 77.32 ± 10.23g (p<0.05), and the control had the lowest final weight 20.08 ± 6.64g. The average weight gain was different between treatments (p<0.05), which presented better results than the control (p<0.05). Treatments A and C expressed the highest mean weight gain 49.90 ± 8.95 and 54.17 ± 4.12 g (p<0.05), respectively. The final biomass was different between treatments, which showed better results than the control group (p<0.05). Survival rate was not different between treatments (p>0.05). However, the control presented the lowest rate of 13.33%, due to trichodinid infestation. Supplemented prebiotics were beneficial for weight gain, final biomass, apparent feed conversion and survival of pirarucu juveniles.