Avaliação produtiva e bromatológica de forragens em sistema de aquaponia

Abstract

The objective of this experiment was to evaluate the production (stature, dry phytomass and fresh phytomass) and bromatological composition (dry matter, crude protein, mineral matter, acid detergent fiber, neutral detergent fiber) of white oats (Avena sativa L.) and ryegrass (Lolium multiflorum Lam.) In an aquaponic system at different fish densities, the chemical and physical quality of the water (dissolved oxygen, total ammonia, nitrite, alkalinity, electrical conductivity and hydrogeonic potential (pH).) The experiment was conducted in the Nucleus of aquaculture at the Federal University of Dom Pedrito, where two fish farming systems were used, with recirculation of closed water, thermoregulated, coupled to a biofilter, and an Ultra Violet (UV) filter, (Avena sativa) and Azevém (Lolium multiflorum) seeds in the density The irrigations were carried out according to the temperature and humidity conditions of the plants, with a duration of 2 minutes each. Nile tilapia juveniles (Oreochromis niloticus) were used, which received commercial extruded feed twice a day. The quality of water, room temperature and water were monitored daily. For the evaluation of the zootechnical performance, weight (g), total length (cm) was estimated. The height of the plants was measured using a millimeter ruler. For the determination of fresh phyto-mass was performed from samples collected in each experimental unit. The experimental design was completely randomized with 2 fish densities and 8 replicates and 2 types of fodder with 4 replicates each, distributed in 2x2 factorial scheme. The results analyzed for height and dry matter (SF) in (kg / m² and thá-1) did not present significant difference (P> 0.05) between the densities D1 and D2 for oats and ryegrass at 15 days of culture. The results for fresh phytomass (FF) showed a significant difference (P <0.05) between oats (10.45 ± 1.09 and 9.15 ± 0.57 kg / m²), with higher phytomass However, ryegrass presented no significant difference (P> 0.05), but produced a larger phytomass at density 2 with 12.38 ± 1.02 kg / m2 and 123.80 ± 10.27t / ha-1. The values observed after the bromatological analsys for dry matter (DM) and acid detergent fiber (FAD) showed no significant difference (P> 0.05) among the tested densities. However, mineral matter (MM), crude protein (CP) and neutral detergent fiber (NDF) showed a significant difference in relation to the analyzed densities and phytomass. Therefore, it can be affirmed that the aquaponic system contributed to the development of the tested forage, being an alternative of cultivation.